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WO2025078157A1 - Procédé, appareil et système d'accès au réseau - Google Patents

Procédé, appareil et système d'accès au réseau Download PDF

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Publication number
WO2025078157A1
WO2025078157A1 PCT/EP2024/077003 EP2024077003W WO2025078157A1 WO 2025078157 A1 WO2025078157 A1 WO 2025078157A1 EP 2024077003 W EP2024077003 W EP 2024077003W WO 2025078157 A1 WO2025078157 A1 WO 2025078157A1
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WIPO (PCT)
Prior art keywords
access device
demand
pilot signal
pilot signals
pilot
Prior art date
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PCT/EP2024/077003
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English (en)
Inventor
Oscar Garcia Morchon
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Koninklijke Philips NV
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Koninklijke Philips NV
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Publication of WO2025078157A1 publication Critical patent/WO2025078157A1/fr
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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0686—Hybrid systems, i.e. switching and simultaneous transmission
    • H04B7/0695—Hybrid systems, i.e. switching and simultaneous transmission using beam selection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/28—Cell structures using beam steering

Definitions

  • This invention relates to a method, apparatus, and system for enhanced communication when a wireless device such as a user equipment perform network access with a wireless access device such as a base station in a wireless system such as a cellular system, a WiFi network or the like.
  • a primary station serves a plurality of secondary stations located within a cell served by this primary station. Wireless communication from the primary station towards each secondary station is done on downlink channels. Conversely, wireless communication from each secondary towards the primary station is done on uplink channels.
  • the wireless communication can include data traffic (sometimes referred to User Data), and control information (also referred sometimes as signalling). This control information typically comprises information to assist the primary station and/or the secondary station to exchange data traffic (e.g. resource allocation/requests, physical transmission parameters, information on the state of the respective stations).
  • the primary station is referred to a base station, or a gNodeB (or gNB) in 5G (NR) or an eNodeB (or eNB) in 4G (LTE).
  • the eNB/gNB is part of the Radio Access Network RAN, which interfaces to functions in the Core Network (CN).
  • the secondary station corresponds to a mobile station, or a User Equipment (or a UE) in 4G/5G, which is a wireless client device or a specific role played by such device.
  • the term "node” is also used to denote either a UE or a gNB/eNB.
  • UEs may use discovery messages to establish new connections with other UEs.
  • This relay node is a wireless communication station that includes functionalities for relaying communication between a primary station, e.g. a gNB and a secondary station, e.g. a UE.
  • This relay function for example allows to extend the coverage of a cell to an out-of-coverage (OoC) secondary station.
  • This relay node may be a mobile station or could be a different type of device.
  • Proximity Services (ProSe) functions are defined inter alia in TS 23.303, and TS 24.334 to enable - amongst others -connectivity for the cellular User Equipment (UE) that is temporarily not in coverage of the cellular network base station (eNB) serving the cell.
  • This particular function is called ProSe UE-to-network relay, or Relay UE for short.
  • the Relay UE relays application and network traffic in two directions between the OoC UE and the eNB.
  • the local communication between the Relay UE and the OoC UE is called device-to-device (D2D) communication or Sidelink (also known as PC5) communication in TS 23.303 and TS 24.334.
  • D2D device-to-device
  • Sidelink also known as PC5
  • the OoC-UE is, e.g., IP-connected via the Relay UE and acts in a role of "Remote UE".
  • This situation means the Remote UE has an indirect network connection to selected functions of the Core Network as opposed to a direct network connection to all Core Network functions that is the normal case.
  • the relay node relays the communications between UE devices.
  • UEs may connect to the core network through a base station when in-coverage.
  • the relay devices may receive and store some information for some time before forwarding it towards the target device.
  • This information that may be stored and forwarded may be discovery messages received from a source UE whereby the relay UE may release them at some point of time later.
  • This information that may be stored and forwarded may be a SIB that may contain a timestamp.
  • cellular networks are evolving to enable more mobile access devices such as satellites, unmanned aerial vehicles, buses or trains that are capable of storing data for some time before forwarding it further.
  • An example relates to a satellite that receives and stores certain data when it is close to a terrestrial gateway and only releases it when the receiving party becomes in coverage.
  • Such mobile access devices may work in a transparent manner or in a re-generative manner. In a transparent mode, the mobile access device acts as a reflector/smart repeater that retransmits the communication sent by, e.g., a gateway, e.g., a Non-Terrestrial Network gateway, towards a UE.
  • a gateway e.g., a Non-Terrestrial Network gateway
  • the mobile access device works as a base station and is able to setup a connection with a UE.
  • the mobile access device may be able to cache same data obtained from the UE or NTN gateway, and transmit it when it is within communication range of the receiver.
  • SSB synchronization signal blocks
  • SIB System Information Block
  • the pilot signals contained in the SSBs include the Master Information Block that allows determining SIB1 that allows performing the initial random-access procedure.
  • the SSBs containing the MIB are transmitted in a regular, periodic fashion. The same applies to SI Bl.
  • pilot signals are expensive energy wise, and thus, from an energy point of view, it may be preferable to reduce the transmission frequency of pilot signals.
  • UEs need more time to perform the required actions, e.g., connect to the network, obtain positioning measurements, etc.
  • Another problem refers to the fact that the access device selection is based on the signal strength only, and other potential parameters are not considered.
  • Another problem refers to the fact that the random-access procedure requires the usage of additional communication resources/time.
  • An aim of the invention is to address above problems when a UE accesses the network.
  • the invention relates to a method and an apparatus for improving the efficiency of pilot signal transmission in cellular systems as well as the access of a UE to the network.
  • a method comprises determining a pilot signal transmission pattern based on one or more factors, such as channel quality, user equipment (UE) density, UE mobility, etc., and transmitting pilot signals according to the determined pattern.
  • An apparatus comprises a transmitter configured to transmit pilot signals according to a determined pattern, and a controller configured to determine the pilot signal transmission pattern based on one or more factors.
  • Another method comprises receiving a pilot signal, determining the preferred pilot signal, whereby the determination may be based on one or more of multiple parameters of the received pilot signals (signal strength, frequency shift, ...), an AI/ML model, a deterministic pilot signal selection procedure.
  • Another apparatus comprises a receiver configured to receive pilot signals, and a controller configured to determine the preferred pilot signal. The invention enables a more flexible, comprehensive and adaptive allocation and processing of pilot signals, which can reduce the energy consumption and latency of the system, and improve the user experience.
  • the invention realizes that is possible to determine which beams can be used by an access device to cover an area.
  • the cellular system may be able to determine where a UE is located. This is feasible in a wireless system with wireless sensing capabilities, e.g., 6G, because sensing capabilities can be used to better determine the location of a UE.
  • pilot signals are selected or transmitted for enabling the required service.
  • the method comprises selecting or transmitting pilot signals for enabling the required service and, prior to or simultaneously to transmitting pilot signals through the determined or obtained beams, sending a configuration message to an access device wherein the message includes at least one of:
  • the method comprises, prior to transmitting pilot signals, transmitting an indication to a user equipment (UE), said indication including at least one of:
  • the method comprises the apparatus
  • pilot signals through the determined or obtained beams wherein the pilot signals are selected or transmitted for enabling the required service comprises transmitting a second set of pilot signals with a second periodicity and/or frequency.
  • the pilot signals include at least one of:
  • the selecting of the beams and/or transmission time used to cover the location of the UE is based on at least one of:
  • AI/ML Artificial Intelligence/ Machine Learning
  • the method comprises adapting a transmission power of the pilot signals based on the determined or obtained presence or location of the UE.
  • the pilot signal may be one of SSBs or SIB1 and the service required by the UE may be one of a handover procedure or wireless communication through a secondary cell.
  • a location unit adapted to determine or obtain the presence or location of a UE
  • a controller configured to determining a service required by the UE, wherein the controller is adapted to select the beams and/or transmission time used to cover the location of the UE, and a transmitter adapted to transmit pilot signals through the determined or obtained beams wherein the pilot signals are selected or transmitted for enabling the service required by the UE.
  • variants of the first aspect may also apply to the second aspect of the invention.
  • the apparatus of the second aspect may typically be included in an access device.
  • a wireless device for accessing a network by a wireless device, said wireless device being adapted to perform beam and cell selection, the method comprising the wireless device:
  • the method comprises the wireless device sending a request to the first access device to receive the on-demand pilot signals upon reception of the first message, and receiving the on-demand pilot signals from the first access device.
  • the on-demand pilot signal indication includes configuration information of on-demand pilot signals distributed by a second access device; and the wireless device receives one or more on-demand pilot signals from the second access device.
  • the method comprises the wireless device selecting a preferred pilot signal from the received periodic pilot signal and on-demand pilot signal, wherein the selecting of the preferred pilot signal is based on a selection process including at least one of:
  • said selection process taking as input the received signal strength of the pilot signal, and at least one of:
  • a wireless device for accessing to a network by a wireless device, said wireless device being adapted to perform beam and cell selection, the method comprising the wireless device:
  • the method comprises selecting the preferred pilot signal and/or cell is based on selection process including at least one of:
  • the selecting of the preferred pilot signal and/or cell may comprise determining a pilot signal and/or cell fulfilling QoS requirements with an energy consumption under a threshold.
  • the method comprises the wireless device using the AI/ML model as default and applying the deterministic algorithm when the performance of AI/ML model drops beyond a threshold.
  • the method comprises the wireless device prioritizing the selection of on demand pilot signals or periodic pilot signals.
  • the method comprises the wireless device: informing a first access device associated to the selected pilot signals about its choice as well as selected parameters over a second access device, receiving configuration parameters for communicating with the first access device from the second access device, and sending a RRCSetupComplete message to the first access device.
  • the method comprises the wireless device receiving a configuration, wherein the configuration is received prior to the reception of on-demand pilot signals, wherein the configuration includes one or more of:
  • the method comprises the wireless device receiving pilot signals, wherein the pilot signals include at least one of:
  • the identifiers and/or number of SSBs may be encoded in the on-demand pilot signal as a field in the on-demand pilot signal.
  • the method comprises the wireless device receiving an on-demand pilot signal from a SCell.
  • the method comprises the wireless device receiving a configuration from a PCell.
  • the method comprises the wireless device: - receiving, from a first access device, periodic pilot-signals,
  • an apparatus adapted to perform beam and cell selection comprising: a receiver adapted to receive at least a periodic pilot signal from a first access device; and controller adapted to decode a first message from a first access device comprising an on-demand pilot signal indication.
  • an apparatus adapted to perform beam and cell selection comprising: a receiver adapted to receive one or more pilot signals including on demand and/or periodic pilot signals, a controller configured to select a preferred beam and/or cell based on the received signal strength of the received pilot signal and at least one of transmitted signal strength of the received pilot signal, time of arrival of the received pilot signal, time difference of arrival, a temporary UE identifier, frequency shift of the received pilot signal, distance to the access device, relative speed with the access device, and type of the received pilot signal.
  • the apparatus of the fifth and sixth aspects of the invention may be included in a User Equipment.
  • a seventh aspect of the invention it is proposed a computer program for improved network access, wherein the program comprises instructions causing a computer to perform the steps of any of third and/or fourth aspects of the invention.
  • Fig. 1 schematically represents the overall cellular system including UEs, RAN, and core network;
  • Fig. 2 provides a schematic representation of a UE and its components
  • Fig. 3 schematically represents different entities involved in a non-terrestrial network
  • Fig. 4 schematically represents a random-access procedure in a wireless network
  • Fig. 5 schematically represents a signalling procedure by an access device
  • Fig. 6 schematically represents the time/frequency distribution of pilot signals through different beams by an access device in a cellular network
  • Fig. 7 schematically represents the location-dependent received signal strength of pilot signals when distributed through different beams by an access device in a cellular network
  • Fig. 8 schematically represents an access device distributing pilot signals through different means
  • Fig. 9 schematically represents the time/frequency distribution of pilot signals through different beams by an access device in a cellular network according to embodiments in this invention
  • Fig. 10 schematically represents the time/frequency distribution of pilot signals through different beams by an access device in a cellular network according to embodiments in this invention
  • Fig. 11 schematically represents the time/frequency distribution of pilot signals through different beams by an access device in a cellular network according to embodiments in this invention
  • Fig. 12 schematically represents embodiments in this invention
  • Fig. 13 schematically represents a message flow according to embodiments in this invention
  • Fig. 14 schematically represents a message flow according to further embodiments in this invention.
  • Fig. 15 schematically represents the distribution of a first set of pilot signals by an access device, the response of a UE that triggers the distribution of a second set of on-demand pilot signals, that can be used by a UE to access the network, and
  • Fig. 16 and Fig. 17 schematically represent options for the time/frequency resource allocation of a first set of pilot signals by an access device, the response indication of a UE that triggers the distribution of a second set of on-demand pilot signals, and the further indication of a UE that triggers the on-demand distribution of a SIB1 through a selected beam;
  • Fig. 18 schematically represents the distribution of a first set of pilot signals at a first frequency by an access device, the response of a UE that triggers the distribution of a second set of on-demand pilot signals at a second frequency according to an embodiment of the invention.
  • Fig. 19 schematically represents an application of an embodiment.
  • Embodiments of the present invention are now described based on a cellular communication network environment, such as 5G.
  • the present invention may also be used in connection with other wireless technologies, and in particular to the connection setup of devices trying to access a wireless network.
  • a typical example is a cellular network, for example a 5G network, possibly including some relay nodes.
  • These relay nodes may be implemented by UEs, such as Sidelink compatible UEs which can operate as relay nodes, or by other types of repeaters.
  • gNB 5G terminology
  • BS base station
  • access device is intended to mean a wireless access device such as a cellular base station or a WiFi access point or a ultrawide band (UWB) personal area network (PAN) coordinator.
  • the gNB may consist of a centralized control plane unit (gNB-CU-CP), multiple centralized user plane units (gNB-CU-UPs) and/or multiple distributed units (gNB-DUs).
  • the gNB is part of a radio access network (RAN), which provides an interface to functions in the core network (CN).
  • CN core network
  • the RAN is part of a wireless communication network. It implements a radio access technology (RAT).
  • RAT radio access technology
  • the CN is the communication network's core part, which offers numerous services to customers who are interconnected via the RAN. More specifically, it directs communication streams over the communication network and possibly other networks.
  • base station BS
  • network may be used as synonyms in this disclosure. This means for example that when it is written that the "network” performs a certain operation it may be performed by a CN function of a wireless communication network, or by one or more base stations that are part of such a wireless communication network, and vice versa. It can also mean that part of the functionality is performed by a CN function of the wireless communication network and part of the functionality by the base station.
  • Section: On demand pilot signals This invention is illustrated in the context of synchronization signals blocks (SSBs) that are transmitted by 5G access devices in a periodic manner. Depending on the frequency band, a different number of SSBs may be transmitted, each of them through a different beam. Transmission of SSBs happens by means of a SSB burst wherein all SSBs are transmitted, time multiplexed and wherein a SSB burst may take up to 5 ms. For instance, for a frequency band between 3 and 6 GHz up to 8 SSBs may be transmitted through different beams. The transmission period of SSBs may vary between 20 and 160 ms wherein a smaller period means that a higher energy consumption is required but a better service (shorter connection time) is feasible.
  • SSBs synchronization signals blocks
  • Fig. 6 describes the periodic transmission of 8 SSBs over time wherein it is possible to observe three SSB bursts, each with 8 SSBs, at time 0 ms, 20 ms, 40 ms, 60 ms, and 80 ms.
  • Fig. 7 shows an illustration of a real-world measurement of the signal strength of pilot signals (in this case the SSB received with the highest signal strength as a function of the location of the measuring device). It is worth observing that such measurements are performed and known to the cellular system to optimize the placement/deployment of access devices. It is worth observing that an access device knows therefore which beams cover best a given area.
  • pilot signals in this case the SSB received with the highest signal strength as a function of the location of the measuring device.
  • a key idea of the invention consists in the on-demand distribution of pilot signals including but not limited to SSBs.
  • pilot signals including but not limited to SSBs.
  • an access device determines the presence of a UE at a specific location, e.g., in Fig. 8 the gNB determines that a UE is approaching and it is approaching towards an area covered by beams transmitting an SSB burst containing SSBs SSB5, SSB6 and SSB7
  • the gNB may then transmit on demand said pilot signals, namely SSB5, SSB6 and SSB7.
  • This on-demand transmission has two effects as shown in Fig. 9 and Fig. 10.
  • Fig. 9 As per Fig.
  • the UE will be able to monitor those on demand SSBs, the on demand SSB burst, and connect to the gNB faster because it does not need to wait for a regular SSB burst.
  • the pilot signals include MIB and acquisition of SIB1 where the RACH parameters can be found.
  • periodic regular pilot signals may be transmitted (at a lower frequency), and on- demand pilot signals (at a higher frequency) may be transmitted in between.
  • the on-demand pilot signals may contain a subset of the regular pilot signals.
  • an on demand SSB burst may contain a subset of the SSBs that are present in a periodic SSB burst.
  • the period of the regular periodic pilot signals (e.g., SSB bursts) can be increased, e.g., from 20 ms to 80 ms, reducing the energy consumption of the cell.
  • the number regular pilot signals is a factor 4 smaller, and thus, the energy consumption due to them is reduced a factor 4.
  • UEs that are moving can still connect in a very efficient manner because pilot signals can now be delivered on demand.
  • This embodiment of this invention may be applicable to different types of pilot signals, e.g., SSBs, SIB1, PRS, etc.
  • the SSB includes the MIB that indicates the time/frequency resources where the SIB1 is located, Le., the time/frequency resources the UE needs to scan to obtain SI Bl. If the SSB is sent on demand, then it can be linked to a SIB1 that may also be sent on demand.
  • This embodiment thus requires acquiring and maintaining a map of the beams that can be used in a given area to convey a given pilot signal.
  • the map may be obtained prior to/during network deployment, e.g., by means of in-field measurements, or based on simulations similar to Fig. 7.
  • Fig. 7 illustrates an area in a city environment and shows different beams, each beam covering a different area of the city environment.
  • the access device transmits a pilot signal over a number of beams close to the location of the UE.
  • the parameters k and m are configurable, and may be indicated to the UE so that the UE knows which on- demand pilot signals it needs to monitor. These parameters may be included, e.g., in the pilot signals (e.g., SSBs) so that the UE is aware of the pilot signals that are being broadcasted. The UE may take this information into account when processing the pilot signals, e.g., when performing beam selection.
  • the access device may adjust the angle of the on- demand pilot signals depending on the location of the UE. For instance, in reference to Fig. 9, UE is approaching between the normal position of SSB6 and SSB5. The access device may rotate / shift the three closest beams when broadcasting the three SSBs so that one of them points directly towards the expected location of the approaching UE as illustrated in Fig. 11. If the access device applies this embodiment of the invention, the measurements (e.g., signal strength measurement) performed by the UE will change between SSB bursts. Thus, an access device may also indicate the fact that the direction of the SSBs in different SSB burst is slightly different.
  • the direction of the SSB bursts may change in a periodic manner, and the UEs may be informed (e.g., indicated in the SSBs themselves) about this periodicity. The UE may then not only determine the best beam, but also the specific direction of the beam.
  • an SSB may include a field that may indicate the periodicity of the changing direction. For instance, if this field is two bits long, the values may be 0, 1, 2, and 3.
  • the value 0 means that the beams transmitting the SSBs remain static in different SSB bursts.
  • the value i means that the beams transmitting the SSBs change direction and repeat themselves every i+1 SSB burst.
  • SSB bursts whose SSBs are transmitted in the same direction will repeat every 80 ms.
  • the UE may indicate beam and direction when sending the initial Preamble RACH message.
  • the access device may change the rotation/shift the pilot signals in different burst to obtain a better estimation of the communication parameters to use with the UE, e.g., beam direction.
  • a UE may transmit a few periodic pilot signals (e.g., at a low frequency) and when detected by a UE, the UE may send an indication that may trigger the distribution of on demand (high frequency)/focused pilot signals. For instance, in the case in which a base station may transmit up to 64 SSBs for frequencies higher than 6 Ghz.
  • each of the SSB's may include an indication that the reception and acknowledgement of one of them by a UE may trigger the distribution of on-demand SSBs (at a frequency higher than 6 Ghz) for further selection by the UE.
  • the UE When the UE selects one of the 8 SSB's at a first frequency (e.g., between 3 and 6 GHz) and sends a PRACH preamble for one the SSB's, the UE triggers the on-demand distribution of SSBs at a different frequency, e.g., 3 SSBs out the 64 SSBs when the frequency is higher than 6GHz, for fine-grained selection.
  • a different frequency e.g., 3 SSBs out the 64 SSBs when the frequency is higher than 6GHz
  • the indication of the on-demand transmission of pilot signals, as well as the corresponding parameters, may be exchanged in a DCI message and/or a MAC CE as discussed in proposals to RANI 116b.
  • the periodic pilot signals SSB's and the on-demand pilot signals SSBs may also be in the same frequency band, and the periodic pilot signals may just be transmitted with a lower frequency/with a longer period.
  • Fig. 15 This is also illustrated by means of Fig. 15 where 100 represents a UE and 101 represents a base station or access device.
  • the distribution of low frequency pilot signals SSB's is represented by arrows 102 and 108 that are transmitted with period Tl.
  • the UE responds with an indication, e.g., a PRACH preamble in 103.
  • a PRACH preamble This indicates to the base station that the UE would like to request on-demand delivery of SSBs, e.g., high frequency SSBs delivered in 104, 105, and 106 transmitted with period T2.
  • the UE can select one of the SSBs and responds with a second PRACH preamble in 107 to perform RACH.
  • a UE 100 When a UE 100 receives a pilot signal as SSB's as in signal 102, the UE 100 may not react to a subsequent RAR message in a RACH but awaits for the delivery of later SSBs (signals 104, 105, 106). In some situations, a UE first acquires the
  • a UE may receive a first set/burst of SSB's, and send the indication to retrieve the second set/burst of on demand SSBs after the selected SSB' beam.
  • each SSB' may include a field (e.g., a bit) indicating the availability of on-demand SSBs so that the UE knows that it can acquire them by sending a signal in some time/frequency time resources, e.g., in the time resources after the SSB's.
  • a field e.g., a bit
  • SSB's For instance, if eight SSB's are transmitted, each of them that is slightly delayed a time T in time, i.e., received at times to, tO+T, tO+2T,...,tO+7T, and UE perceives/measures SSB' number i (i refers to the preferred SSB' index) as the best one (e.g., based on the measured signal strength/RSRP), the UE may send an indication in time tO+7T+(i+l)Tl, where T1 may be different than T (i.e., a time resource dependent on the preferred i SSB' index).
  • the indication may be just one bit (on/off) so that if the access device receives "anything" at time tO+7T+(i+l)Tl, it may determine that further on-demand pilot signals, e.g., SSBs, are required for i (i.e., around the area where SSB' with index i was transmitted/received).
  • a UE may just transmit the selected SSB' index i at some specific time/frequency resources.
  • This time slot at the same frequency range of the receive SSB may be seen as a RACH occasion.
  • This indication transmitted in such a RACH occasion may be, e.g., a pre-agreed preamble or other pre-agreed signal such as an uplink wake-up signal.
  • a UE receives the SSB's, and the UE determines that one of them, e.g., the fourth SSB', is the preferred one, it may then transmit an indication in the fourth time interval 1102 in the second part 1101 of the first 10 ms frame. In general, an indication in some predefined resources.
  • this indication will then trigger the distribution of the second set of on-demand SSBs 1104 in the first part 1103 of the subsequent second 10 ms frame.
  • this is an indication for the access device to deliver the on-demand SSBs, and thus, it does not need to be a complex signal to allow the UE to perform the RACH. It may be a simpler signal, e.g., just a preamble and a short flag indicating the preferred on-demand SSBs.
  • the second set of on-demand SSBs 1104 is "amplified" for clarity purposes in 1105. The UE may then choose one of the SSBs in this second set of on-demand SSBs as the preferred one.
  • This may be again indicated by means of an indication transmitted by the UE in time resources 1106 in the second part 1108 of the subsequent second 10 ms frame.
  • the time resources may be chosen based on the preferred SSB, e.g., as illustrated in 1107 (that amplifies 1106) and shows that the indication is transmitted at a time that corresponds to the preferred 7 th SSB (since in this example, the 7 th SSB is the preferred one by the UE).
  • the transmission of this further indication by the UE may then trigger the on-demand distribution of SIB1 through that beam.
  • this indication may also be transmitted sometimes in other time/frequency resources, and it may also indicate not only the most preferred SSB', but also the second, third,... most preferred SSB's as well as potentially other helper information such as, e.g., the received signal strength of different SSB's, in general pilot signals.
  • this reported information by the UE may be used by the network (e.g., source cell or primary cell or secondary cells) to coordinate and determine the cell that is most suitable to be served by a UE and may transmit on-demand SSBs. For instance, if a UE reports information related to periodic SSBs of three potential cells, the cells may coordinate among themselves to determine which of the cells is the most suitable one to transmit the on-demand SSBs'.
  • the network e.g., source cell or primary cell or secondary cells
  • This coordination may consist in the exchange of the received indications via an interface, e.g., Xn interface, so that the cells (or the central unit steering the distributed units of the cells) determine which of the cells should transmit an on-demand SSB burst, and which SSBs should be included in such on-demand SSBs.
  • an interface e.g., Xn interface
  • the transmission by the UE of the indication is performed in the same frequency resources used by the access device to distribute the SSBs, instead, the UE may use a different set of frequency resources, e.g., that may be included / indicated in the SSB, either implicitly or explicitly, or described in a technical specification, e.g., for UEs capable of supporting the on-demand reception of pilot signals.
  • This set of frequency resources would be different than the frequencies used for normal SSBs (synchronization raster).
  • the frequency resources maybe an offset with regard to the frequency resources used to receive pilot signals, and the offset maybe encoded in the SSB's or in the technical specification. This is illustrated in Fig. 17 where it can be observed that the information distributed by the access device is in frequency fO while the indications provided by the UE are in frequency fl (offset is fl-fO).
  • the on-demand SSBs may also be transmitted in a different frequency range than periodic SSB's, e.g., off-raster as indicated in submissions to RANI 116bis.
  • the frequency band may be indicated to the UE by a cell via a configuration message.
  • the frequency band used to transmit the on-demand SSBs may be encoded in periodic SSB's, e.g., as a frequency offset, similar to the embodiment illustrated by means of Fig. 17 wherein the indication transmitted by the UE is in frequency fl.
  • the first set of SSBs' may be in a first frequency, e.g., in a first frequency band (e.g., FR1) and the second set of SSBs may be in a second frequency, e.g., a second frequency band, e.g., FR2.
  • the second set of SSBs 1104 as in Fig. 17 may be transmitted in a different frequency or frequency band than the first set of SSB' 1100. This allows an access device to transmit periodic pilot signals in a first frequency band only, and only distribute pilot signals in other frequency bands on demand. This is illustrated by means of Fig.
  • pilot signals e.g., SSBs
  • a first frequency fl, e.g., in a first frequency band
  • low frequency e.g., every 80 ms
  • Those low frequency pilot signals are represented by 1300 and 1305 respectively and pilot signals 1300 are "amplified" by means of 1301.
  • 1301 represents the distribution of a first set of SSBs', in this example, consisting of four SSBs' denoted as 13011, 13012, 13013, and 13014.
  • Signal 1302 represents response of a UE indicating a preferred pilot signal in the first set of pilot signals 1300.
  • the reception of signal 1302 triggers the distribution of on-demand pilot signals 1303 at a second frequency and with a higher frequency (in this example, every 20 ms).
  • This second set of on-demand pilot signals may consist of a few on-demand pilot signals, in this example, four SSB bursts.
  • One of those sets of pilot signals is "amplified" by means of 1304 showing that it comprises, in this example, six SSBs denoted as 13041, 13042, 13043, 13044, 13045, and 13046.
  • An application of this specific example is illustrated by means of Fig. 19 wherein a UE 1400 is located.
  • An access device distributes a first set of pilot signals at a low frequency, each set of pilot signals including four signals covering a different area.
  • each of these pilot signals is denoted by 14011, 14012, 14013, and 14014. Since UE 1400 is within area 14013, the UE 1400 may indicate this preference for a pilot signal in this area. As a response the access device may distribute a second set of on-demand pilot signals in that area. This second set of on-demand pilot signals may cover subareas 14041, 14042, 14043, 14044, 14045 and 14046.
  • a method for energy efficient transmission of pilot signals comprising: receiving, by a wireless device, a first set of pilot signals at a first frequency and/or a first periodicity; transmitting, by the wireless device, a first message indicating a request to receive a second set of pilot signals at a second frequency and/or a second periodicity, receiving, by the wireless device, a second set of pilot signals at a second frequency and/or a second periodicity.
  • a UE may be in idle or inactive state. When idle, the UE may have a network identifier, and thus, it may directly request on-demand SI Bl, e.g., by means of Message 3 /A in the random-access procedure.
  • the provided on-demand SIB1 may be also unicasted to the UE, e.g., by scheduling the SIB1 transmission by means of a DCI message.
  • the on-demand SIB1 may not be always unicasted, but sometimes it may be broadcasted since multiple UEs may request it simultaneously, and thus, it may be more efficient to broadcast it. This may still be indicated by means of a DCI message.
  • a UE may also be in inactive mode, and in that case, the UE may lack a network identifier, and thus, it may need to request an on-demand SIB1 by sending an indication, in a different manner, e.g., by sending a preamble in message 1/A of the random-access procedure.
  • the indication sent by the UE after reception of the first set/burst of SSB's or second set/burst of SSBs may be used to trigger the distribution of SIB1.
  • legacy systems e.g., 5G Release 18
  • whether the indication sent by the UE triggers the distribution of on-demand SSBs or SIB may be encoded in the indication itself, e.g., it may be a different code (e.g., transmitting 1010 instead of 0101).
  • the UE may transmit a message, e.g., a pilot signal, e.g., a wake up signal, an on demand or a periodic pilot signal (e.g., a sounding reference signal or SRS), e.g., over a wide beam, which can be received by one or multiple access devices.
  • a pilot signal e.g., a wake up signal
  • an on demand or a periodic pilot signal e.g., a sounding reference signal or SRS
  • the access device that receives the strongest signal from the UE may send an indication to the other access devices in the vicinity, informing them of the presence of the UE and its approximate location.
  • the access devices may then transmit on- demand pilot signals (e.g., SSBs) over narrow beams that are directed towards the UE.
  • SSBs on- demand pilot signals
  • the UE may monitor these on-demand pilot signals and select the best one based on the received signal quality.
  • the UE may then send a feedback message to the access device that transmitted the selected pilot signal, indicating its preference and requesting a data transmission.
  • the access device may then establish a communication link with the UE over the selected beam and start transmitting data.
  • a key aspect in this embodiment refers to the fact that the UE needs to send its message in some specific resources.
  • the UE may learn the resources to "wake up" access devices from a single access device that broadcasts that information regularly. This allows the wireless device/UE to learn the timing of the access devices in the area, and the resources to be used to send the message. The UE may then send the message in those resources.
  • This embodiment allows saving energy because access devices may remain silent and only transmit on demand SSBs when requested by a wireless device such as a UE.
  • the signal transmitted by the UE may include an indication about the on-demand SSBs that are required:
  • Number of pilot signals e.g., number of SSBs
  • Number of repetitions e.g., two, three, four,... SSBs bursts
  • Periodicity of the on-demand SSBs Periodicity of the on-demand SSBs.
  • This indication may be coded as part of the pilot signal, e.g., it may indicate the number of SSBs in an SSB burst, the number of SSB bursts that are left to be transmitted, and how frequently the SSBs / SSB bursts are distributed. This may be, e.g., some fields in the SSB and or PBCH.
  • a first set of periodic SSB's may be useful in some cases, e.g., when a target cell or a secondary cell always needs to make sure that UEs can potentially connect to it.
  • These pilot signals may allow UEs to get synchronized in absence of other input or coordination by the network.
  • the network may coordinate (e.g., in handover or when a primary cell coordinates dual connectivity or carrier aggregation), these periodic pilot signals (SSB's) may be absent.
  • a first access device may indicate to the UE that it is required to connect to a second access device (e.g., target access device or secondary access device, etc) for a given service (e.g., handover, dual connectivity, etc).
  • the first access device may then indicate to the UE that it has to monitor for on- demand pilot signals (e.g., SSBs) from those cells, and it may request those cells to distribute on demand pilot signals.
  • on- demand pilot signals e.g., SSBs
  • the UE may receive/measure the on-demand pilot signals of two or more second access devices, select one of them, and access the chosen second access device (e.g., via RACH). Then the chosen second access device may inform the first access device about the choice.
  • the UE may receive/measure the on-demand pilot signals of two or more second access devices, select one of them according to a policy / configuration, and indicate the selection to the first access device.
  • the first access device may then inform the chosen second access device and obtain/negotiate communication parameters for the UE that may be provided to the UE.
  • a method that can be implemented in a device adapted to: receiving, by the device, a first set of pilot signals with a first periodicity from a first access device, e.g., the SCell or PCell, transmitting, by the device, an indication to obtain a second set of on-demand pilot signals from a second access device, receive, by the device, a second set of on-demand pilot signals with a second periodicity from the second access device, and access, by the device, the second access device,
  • a first access device e.g., the SCell or PCell
  • first and second device may be the same device (e.g., SCell) or different devices (e.g., PCell and SCell, respectively) and where the second set of on-demand pilot signals may be SSBs or SIBl.
  • the on-demand pilot signals follow the normal transmission timing/slots, but are only transmitted on-demand, Le., when needed, e.g., when a UE is detected or the presence of a UE is indicated.
  • the on-demand pilot signal includes a timing value (e.g., the offset with respect to a regular pilot signal). This timing value allows a UE to determine the schedule of the regular pilot signals and the position of the on-demand pilot signal with respect to the regular pilot signal.
  • the embodiments in this invention may be applicable to a wide range of scenarios such as handover procedures wherein a UE moves from a source access device to a target access device, e.g., as described in Clause 9 in TS 38.300 V17.6.0. It may also be applicable to multiconnectivity use cases where a multiple Rx/Tx capable UE may be configured to utilize resources provided by two or more different access devices, e.g., as described in TS 37.740 V17.6.0, where an access device may be a primary access device or primary serving cell/node and another access device may be a secondary access device or secondary serving cell/node.
  • a (target) access device may obtain the location of the UE from a (source) access device or primary service cell that is requesting the handover of the UE from the (source) access device to the (target) access device or that is requesting/negotiating that the (target) access device becomes a secondary serving cell, etc.
  • the (source) access device may indicate the one or more of presence/location of the UE, speed, acceleration, etc to the (target) access device that triggers the distribution of on-demand pilot signals.
  • the (source/target) access device may know the presence/location/speed/acceleration of the UE by using a sensing-based approach because: the source (and/or target) access device has wireless sensing capabilities allowing the accurate positioning of the UE; and/or the source (and/or target) access device has determined the accurate UE location (e.g., by means of a positioning procedure (e.g., using positioning signals)) or inaccurate UE location (e.g., by determining the beam used to communicate with the UE (determining the direction of the UE) and using the timing advance to determine the distance to the UE); and/or the source (and/or target) access device uses an AI/ML model that allows estimating the location based on received measurements, pilot signals, etc from the UE; and/or the source (and/or target) receives an indication or signal from the UE; and/or the target access device receives an indication from the source access device about the presence/location of the UE.
  • a positioning procedure e.g., using positioning signals
  • the access device uses wireless sensing, e.g., enabled by a radar-based approach wherein the access device uses a pilot signal such as a chirp or an OFDM-based pilot signal to determine the presence of active or passive objects.
  • a pilot signal such as a chirp or an OFDM-based pilot signal
  • the access device may trigger the decision to transmit an on-demand pilot signal whereby the location is inferred by means of the wireless sensing capabilities of the access device.
  • an access device is configured with an Artificial Intelligence (Al)/Machine Learning (ML) model that allows the access device to predict the location/presence and/or other position related parameters such as speed, acceleration, rotation, etc based on previous measurements.
  • Al Artificial Intelligence
  • ML Machine Learning
  • a UE may send a signal, e.g., a reference signal that may be detected by the access device and may trigger the transmission of pilot signals such as SSBs.
  • This signal may be indicative of the request for a pilot signal.
  • a UE may transmit this signal when it is trying to or wishes to access the network.
  • Communication resources e.g., a frequency band (e.g., certain frequency resources) may be reserved for the transmission of this signal, e.g., a frequency band that is reserved for this purpose.
  • Access devices may monitor these communication resources.
  • the signal may be a common signal, e.g., including a well-known preamble and an identifier indicative of the request for on-demand pilot signals.
  • Multiple access devices may receive the UE signal, and may coordinate with each other to determine which of the access devices is best located to provide access to the device. This may be determined based on, e.g., the time of arrival and measured signal strength of the received UE signal at those multiple access devices since the time of arrival/measured signal strength allow the multiple access device to determine the rough location of the UE, and from there, determine which of the multiple access devices may have the best connection.
  • UE specific fields such as e.g. a random identifier RID randomly generated by the UE with the purpose to identify itself in this initial communication or an ID indicative of its capabilities.
  • Multiple access devices may receive the UE signal, and may coordinate with each other to determine which of the access devices is best located to provide access to the device. This may be determined based on, e.g., the time of arrival and measured signal strength of the received UE signal at those multiple access devices since the time of arrival/measured signal strength allow the multiple access device to determine the rough location of the UE, and from there, determine which of the
  • the multiple access device may interact with each other via a communication interface (e.g., Xn interface) or via the core network, exchanging, e.g., the direction from which the signal was received and/or received power or time of arrival.
  • the access device(s) may also be able to determine the (rough) location of the UE based on said signal so that an on-demand pilot signal may be better directed towards the location of the UE. Once they have determined the most suitable access device, one or more selected access devices transmit the on-demand pilot signal towards the UE. This may be done using one or a few SSBs covering the rough location of the UE.
  • the on-demand pilot signal may be generic or may include some fields included in the UE transmitted signal such as RID so that the UE can discern the pilot signals to be used to select the right beam/access device, e.g., a UE should only use pilot signals including its previously transmitted RID.
  • a (target) access device may sense the presence of UEs, e.g., by means of wireless sensing or other techniques such as the monitoring of pilot signals/measurements reported by the UE, e.g., measurements of pilot signals transmitted by the access device or pilot signals transmitted by the UE such as Sounding Reference Signal or an up-link wake up signal.
  • the (target) access device may determine the instant of time to send the on- demand pilot signals and communicate this information to the UE, e.g., through a source access device. This allows the UE to know when to expect exactly the on-demand pilot signals from the target access device. The target access device may also consider the actual distance to the UE (and the corresponding propagation time) when informing the UE about the timing of the on-demand pilot signals. Similarly, the (source) access device may determine when / where the (target) access device should transmit the on-demand pilot signals, and indicate this timing to the UE and indicate this timing/location to the (target) access device.
  • the (source) access device/primary serving cell may indicate the (target) access device / (secondary) service cell when / where to distribution pilot signals.
  • the SIB1 is also transmitted on demand similar to the SSB allowing for further access to the access device. For instance, when an access device sends a wake-up signal to a UE, e.g., as in a paging message, the access device may also start transmitting a pilot signal such as SIB1 to allow the UE to retrieve the access device information encoded in SI Bl.
  • a pilot signal such as SIB1
  • the on-demand pilot signal e.g., on demand SSB
  • the on-demand pilot signal includes an identifier (e.g., a bit or flag) indicating whether it is an on-demand pilot signal so that the UE can differentiate it from periodic / non-on-demand pilot signals.
  • an identifier e.g., a bit or flag
  • This identifier may be transmitted as part of the on-demand pilot signal, e.g, in the SSB or PBCH.
  • the on-demand pilot signal e.g., on demand SSB
  • the on-demand pilot signal includes an identifier to identify the on-demand pilot signal, e.g., to indicate the UE or UE type it is addressing so that the UE can determine whether the received on-demand pilot signals are addressed to it, or not.
  • the UE may have received such identifier previously from the (target/source) access device distributing the on- demand pilot signals, e.g., through the source access device. This allows for faster access.
  • the source access device may have a preference for target access devices delivering regular (pilot) signals or on-demand signals.
  • indications for a UE included in the on-demand pilot signals may be included as part of the on-demand pilot signal, e.g., on-demand SSBs, as a flag and/or field in the SSB / PBCH.
  • the energy consumption of the UE and of the network does not only depend on the transmission of pilot signals, e.g., SSBs, either periodic or on-demand, but also on the transmission power.
  • the energy consumption also depends on the choice of the UE of the preferred cell. If a cell transmits a pilot signal, e.g., SSBs, with a very high transmission power, a UE may prefer to select that cell; however, this will incur higher energy consumption for the cell and the UE because of the higher transmission power. Instead, the UE may have selected another cell that is closer by and could enable the communication with lower energy requirements.
  • the access device may adjust the transmission power of pilot signals, e.g., SSB bursts, depending on the location of the UE.
  • pilot signals e.g., SSB bursts
  • the access device may adjust the transmission power of the on-demand pilot signals depending on the location of the UE. If the UE is further way, the pilot signals can be transmitted with a higher transmission power while if the UE is closer, the transmission power can be reduced.
  • the access device may not have knowledge of the UE location directly, and it may just get an indication, e.g., from another access device about how close/far a UE is, and this may allow the access device to adjust its power transmission. In some cases, the access device may announce/indicate its capability to adjust its power transmission so that other devices may make use of this feature.
  • the signal strength of the transmitted (on-demand) pilot signals may also be adjusted, e.g., based on the rough location of the UE and/or location of the selected access devices, in order to save energy and reduce interferences.
  • This may be done by means of an algorithm such as deterministic algorithm or propagation model or neural network system that utilizes machine learning algorithms to predict the optimal transmission strength based on various factors such as target location, signal propagation features, environment, and user equipment conditions.
  • the algorithm may determine the transmission power of the pilot signals. This ensures that the pilot signals are transmitted efficiently, reducing energy consumption and improving network performance.
  • the selected transmission power of the pilot signal may be included in the pilot signal, e.g., in the SSBs. For instance, if there are four potential transmission power values, e.g., (very low, low, high, very high) two bits are used to indicate the selected transmission power.
  • a UE receiving one or more pilot signals may consider not only the measured signal strength of the received pilot signals, but also transmission power that is indicated in the received pilot signal.
  • the UE may select the one selected with a low transmission power because it may be indicative of an access device that is better located to provide access.
  • This embodiment can then be used in the cell selection process wherein the UE does not only consider the signal strength / quality of the SSBs, e.g., RSRP, but the impact on the energy consumption.
  • a UE may be informed by an access device, e.g., source access device, about the transmission power of the pilot signals used by another access device, e.g., a target access device.
  • the access device may inform the UE via, e.g., an RRC message. Additionally/alternatively, this may also be a configuration provided to the UE by a NF in the core network and applicable to a given tracking area. Additionally/alternatively, this may be a configuration provided by the OAM.
  • This embodiment of the invention is advantageous so that the pilot signals do not need to be modified (e.g., compared to R15 in 4G) and remain backwards compatible, and still, the network/RAN can reduce energy consumption when transmitting pilot signals, and a UE can make the right access device/beam selection when the UE considers not only the received signal strength but also the transmission signal strength.
  • the energy consumption is also reduced because the subsequent communication between UE and selected cell can be done using a lower transmission power.
  • a UE may receive information about the transmission signal strength of pilot signals used by a target access device, e.g., a secondary serving cell, from a source access device, e.g., a primary serving cell.
  • the information may be included in the SIB1 of the source access device, or SIB1 of the target access device, or in a separate message sent by the source access device.
  • the source access device may have received this information from the target access device, e.g., via Xn interface or other means. This allows the UE to consider the transmission signal strength of the pilot signals along with the received signal strength when selecting a target access device or beam.
  • This embodiment of the invention is advantageous because it does not require modifying the pilot signals themselves, and it can leverage the existing communication channels between the source and target access devices and the UE.
  • a UE may report the measured signal strength of the pilot signal (SSBs), e.g., in the PRACH message or in an UCI, or in an RRC message, so that the access device adjusts its transmission signal strength and prevents the waste of energy. For example, the UE may indicate whether the received signal strength is above or below a certain threshold, or within a certain range, or provide a precise value. The access device may then increase or decrease its transmission power based on the feedback from the UE, or maintain it at the same level.
  • This embodiment of the invention is advantageous because it allows the access device to dynamically adapt its transmission power to the channel conditions and the UE's location, and to save energy when the pilot signals are not needed or can be transmitted with lower power.
  • the UE may also benefit from reduced interference and improved signal quality.
  • a UE may make use of the time of arrival of a pilot signal, e.g., an on-demand SSB, to select a preferred access device or beam. For instance, the UE may measure the time difference between the reception of an SSB from a first access device and the reception of a SSB from a second access device. The UE may then compare this time difference with a threshold or a range of values to determine whether the target access device or beam is closer or farther than the source access device or beam. The UE may then select the target access device or beam if it is closer or within a desired range, or reject it if it is farther or outside a desired range.
  • a pilot signal e.g., an on-demand SSB
  • the UE may be configured with a procedure to process pilot signals including on-demand and/or regular.
  • the procedure may be configured to have a preference for either on-demand or regular (pilot) signals, e.g., it may prefer on-demand signals because of the likely improved performance. However, it may also allow for regular signals in some circumstances, e.g., when on-demand signals or not available or when the performance (e.g., received signal strength) is low.
  • the UE does not only use the (transmitted/received) signal strength of the pilot signal (e.g., on demand or regular pilot signal such as SSBs) to select a pilot signal/cell but also other parameters extracted from it such as the frequency shift to determine the pilot signal to use, e.g., the pilot signal to use as received from one or more access devices.
  • the pilot signal e.g., on demand or regular pilot signal such as SSBs
  • Fig. 12 illustrates a situation in which a UE moves towards a second access device (gNB_2) but is actually closer to a first access device (gNB_l). If only the signal strength is used by the UE, the UE is likely to select beam SSB_1_2 associated to the first access device.
  • UE can determine that the UE is getting closer to the second access device and moving away from the first access device so that the UE may rather select a beam/SSB/pilot signal from the second access device, e.g., SSB_2_5. The reason of this selection is that UE will be close to the second access device in a short period of time, and then the energy consumption for the network / UE will be lower.
  • Other parameters that may be used as part of the pilot signal / cell selection are parameters related to the (estimated) distance or (relative) speed of the access device.
  • the distance to a satellite may be estimated from the location of a UE and the ephemeris data of the satellite that may be known to the UE, e.g., it may have received this information from a primary service cell.
  • the (relative) speed may be obtained knowing the speed of the UE and the speed of the access device, e.g., a satellite, a fixed terrestrial access device, or an access device mounted on a vehicle such as a bus.
  • a UE may determine the need to perform a data transmission DT that is expected to take some time T.
  • the UE when performing beam / pilot signal / access device search and selection, may determine a pilot signal / access device that will be able to provide a connection for the transmission of data DT during time T.
  • This is illustrated by means of Fig. 12, wherein the selection of access device gNBl may have not allowed for the whole transmission of data D requiring a handover from access device gNBl to gNB2; while by selecting access device gNB2 directly, UE can ensure that the whole data transfer can be performed without requiring handovers, and thus, reducing energy consumption.
  • the network may determine the need to perform a data transmission DT to a UE that is expected to take some time T.
  • the network may then send a paging message to the UE.
  • the UE may get an indication (paging cause) of the amount of data to be received, and/or the type of data, and/or the time interval in the paging message that may be used by the UE to determine which beam / pilot signal / access device is most suitable to select.
  • the network may, based on information gathered from the device / UE (e.g., location, movement pattern, ...) determine the access device that is most suitable to provide the data transfer, and the network may indicate that access device to the UE.
  • the network may trigger the selected access device to distribute on demand pilot signals for the UE to connect. For instance, and referring to Fig. 12, the paging message may be delivered to UE via gNB_l. The network may then determine that UE is moving towards gNB_2 (e.g., based on the parameters received in the UE response message and/or by means of wireless sensing) and thus, it is most suitable if UE connects to gNB_2. The network may then indicate to UE that it should connect to gNB_2. gNB_2 may then transmit an on-demand SSB with a highest transmission power to reach UE and allow UE to connect to gNB_2. Note that this may be done knowing that UE is rapidly approaching gNB_2 and then the transmission power will be reduced / lower allowing for efficient network / UE operation.
  • the UE when access devices deliver pilot signals, the UE does not only use the signal strength of the pilot signal (e.g., on demand and/or regular pilot signal such as SSBs) but also other parameters extracted from it the time of reception / time difference between reception.
  • the logic in here is that if the access devices are synchronized to the extent to transmit simultaneously the pilot signals or the transmission time is included in the pilot signals and the time of different access devices is very well synchronized, then a UE can determine the distance to the access devices, or at least, determine which access devices are closer/further away.
  • the apparatus e.g., User Equipment (UE)
  • UE User Equipment
  • QoS Quality of Service
  • This embodiment integrates several key features to ensure efficient and optimized selection of pilot signals and cells, thereby reducing overall network energy consumption while maintaining service quality.
  • this embodiments may integrate several features (1) to (8) described in other embodiments as follows: (1) The apparatus incorporates a multi-faceted decision-making algorithm which evaluates various parameters derived from the pilot signals, such as signal strength, frequency shift, and time of reception. By analyzing these parameters, the apparatus can discern the most suitable pilot signal and access device, ensuring that the energy consumption remains below the predefined threshold.
  • the apparatus measures the received signal strength of pilot signals transmitted by multiple access devices (e.g., base stations or satellites). It not only considers the signal strength but also assesses the signal quality, such as Signal-to-Noise Ratio (SNR) or Reference Signal Received Power (RSRP).
  • SNR Signal-to-Noise Ratio
  • RSRP Reference Signal Received Power
  • the apparatus prioritizes signals that meet the QoS requirements with the least power consumption. For instance, if the UE receives pilot signals from two access devices with RSRP1 and RSRP2 as the measured RSRP for access device 1 and access device 2, respectively; and both RSRP1 and RSRP2 are higher than a threshold; then UE may prefer / choose that pilot signal / access device that indicates / transmits with the lowest transmission power TxPw.
  • the apparatus measures the time of arrival of pilot signals. By calculating the time difference between the reception of signals from various access devices, the apparatus can infer which access device is closer. Selecting a closer access device typically results in lower power consumption due to reduced path loss and interference. Additionally, (4) the apparatus evaluates the frequency shift of received pilot signals. By analyzing the Doppler shift, which indicates the relative speed between the UE and the access devices, the apparatus can predict the movement trend and select a pilot signal from an access device with a favourable trajectory, e.g., that the UE is moving towards. This predictive selection ensures sustained QoS while minimizing power consumption and reducing the changes of handover or cell reselection.
  • the apparatus employs an AI/ML model that takes into account historical and real-time measurements of signal strength, frequency shift, time of reception, and other relevant parameters.
  • the AI/ML model is trained to recommend the optimal pilot signal and access device to minimize energy consumption while fulfilling QoS requirements.
  • the model is periodically updated based on network feedback and the UE's operational context.
  • the access devices dynamically adjust their transmission power based on feedback from the UE.
  • the UE reports the measured signal strength and other relevant metrics to the network, which in turn, adapts the transmission power of the pilot signals. This dynamic adjustment helps in maintaining the desired QoS with minimal power expenditure.
  • the UE is capable of receiving context-specific AI/ML models from the network.
  • the apparatus includes a fallback mechanism to ensure robustness. If the AI/ML-based selection process fails to yield satisfactory results due to unforeseen circumstances, e.g., the selected pilot signal/access device fail to fulfil QoS requirements, the UE reverts to a baseline algorithm. This baseline algorithm typically selects the pilot signal with the highest received signal strength that meets the minimum QoS criteria, ensuring continuous operation.
  • This embodiment of the invention ensures that the apparatus effectively selects the preferred pilot signal and/or cell by evaluating multiple parameters, employing advanced AI/ML techniques, and dynamically adapting to network conditions.
  • the result is an optimized balance between maintaining QoS standards and minimizing energy consumption, thereby enhancing the overall efficiency of the communication system.
  • the UE may use an AI/ML model to determine the pilot signal to choose from the received/measured pilot signals sent by one or more access devices.
  • the AI/ML model may be optimized to take as input measurements from one or more access devices, where the measurements may include one or more of the measured signal strength, the transmitted signal strength, frequency shift, the time of reception or arrival, difference time of reception or arrival, estimated distance, estimated speed,... and the measurements may be a time series of measurements.
  • the UE may use the AI/ML model to obtain a recommendation on the pilot signal / cell to choose, that may give an indication on, e.g., the best SSB and/or cell, e.g., with the goal of reducing the energy consumption.
  • the AI/ML model that the UE uses to select the pilot signal may not be a generic one, but rather one that is specific for a given area and/or the type of service that the UE seeks. For example, if the UE is in a rural area where there are fewer access devices and more interference from other sources, the AI/ML model may take into account different factors than if the UE is in an urban area with dense access device deployment and high traffic demand.
  • the AI/ML model may prioritize access devices that offer lower delay and higher reliability, while if the UE is seeking a high-throughput service, such as downloading or streaming, the AI/ML model may prioritize access devices that offer higher bandwidth and better coverage.
  • the UE may receive the AI/ML model from the network or download it from a cloud server, depending on its location and service request.
  • the UE may also update the AI/ML model periodically or dynamically, based on the feedback from the network or its own measurements.
  • a UE may select a given access device and/or beam of an access device by measuring the signal strength / RSRP of a pilot signal, e.g., SSB.
  • a pilot signal e.g., SSB.
  • pilot signals may be transmitted with a lower transmission power, reducing energy consumption and interferences having as only goal to get the UE synchronized with the target cell.
  • the UE may get an indication of the cell / beam to select via a message (e.g., RRC message, MAC CE, etc).
  • a UE may be informed by a (source) access device about the identity / pilot signal of a (target/secondary) access device that it is supposed/required to select, e.g., in a given context (a given location, a given time window, etc).
  • the (source) access device may also inform a (target) access device about the UE and the need to distribute on-demand access signals whereby the (source) access device when informing about the UE, also provides the (target) access device with information that allows the (target) access device to transmit the pilot signal with a lower/the suitable transmission power, e.g., the rough location of the UE, or the transmission power itself, etc, e.g., as illustrated in other embodiments.
  • a lower/the suitable transmission power e.g., the rough location of the UE, or the transmission power itself, etc, e.g., as illustrated in other embodiments.
  • a UE may inform the network about its capabilities, e.g., which type of parameters it is capable to measure or consider when performing access device /cell (re-)selection, and the network may provide the UE with an AI/ML model tailored to those capabilities. For instance, a UE that is not capable of measuring the frequency shift of the received pilot signals does not require an AI/ML model that takes it into account. This allows reducing the communication, storage, and computational resources of the system/UE.
  • the AI/ML model may be based on a neural network such as convolutional neural network (CNN), a recurrent neural network (RNN), a long short-term memory (LSTM) neural network, etc.
  • CNN convolutional neural network
  • RNN recurrent neural network
  • LSTM long short-term memory
  • the AI/ML model may be provided by an access device, e.g., source access device prior to performing a handover operation or by a primary service cell prior to accessing a secondary serving cell. Additionally/alternatively, it may be provided by a NF entity such as the AMF when entering a given area, e.g., a tracking area.
  • an access device e.g., source access device prior to performing a handover operation or by a primary service cell prior to accessing a secondary serving cell.
  • a NF entity such as the AMF when entering a given area, e.g., a tracking area.
  • a UE may rely on a baseline algorithm/procedure, e.g., a deterministic algorithm or a probabilistic algorithm, to select a pilot signal/cell (e.g., select the pilot signal with the highest signal strength received in the last time window) and/or an AI/ML model-based algorithm/procedure to select a pilot signal/cell.
  • the baseline algorithm/procedure may be, e.g., as in a cell selection procedure based on the measured RSRP (Reference Signal Received Power) of the Synchronization Signal Blocks (SSBs).
  • the UE selects the cell with the highest RSRP value that also meets the minimum required RSRP value for cell selection.
  • the UE may be configured to use the AI/ML model-based algorithm/procedure as default using the recommendation provided by an AI/ML model configured to the situation at hand, e.g., selecting an access device distributing on demand pilot signals or whose pilot signals given a high recommendation.
  • the UE implements a fall-back algorithm to switch back to the baseline algorithm to select a pilot signal when the AI/ML model-based algorithm/procedure/method fails to return a good enough result. This situation may be due to the misconfiguration of the UE, the choice of the wrong AI/ML model in the current UE environment, the change of the UE environment, etc.
  • the UE When the UE determines that the AI/ML model-based algorithm/procedure/method has failed or is failing to return a good enough result in a given context (e.g., for time longer than a time threshold, a number of attempts, in a given area,...), the UE can fall-back to a baseline procedure.
  • the on-demand delivery of pilot signals may be coordinated by the network or it may be triggered by the UE (e.g., with a given signal/indication) when it is an "indication-capable UE". This is a problem because it is needed to determine which method is used when/in which situation.
  • a UE may indicate to the network its capabilities and/or the network may configure/allow an "indication capable UE" to transmit an indication in a given situation or not.
  • the UE may include an indication of its capabilities in a registration message or a measurement report message sent to an access device.
  • the indication may be a bit flag, a code word, or any other suitable format.
  • the access device may configure the UE with a parameter that indicates whether the UE is allowed to trigger on-demand SSBs or not.
  • the parameter may be transmitted in a radio resource control (RRC) message, such as an RRC reconfiguration message, or a non-access stratum (NAS) message, such as a configuration update command message.
  • RRC radio resource control
  • NAS non-access stratum
  • the UE may store the parameter in its memory and use it to decide whether to transmit an indication to request on-demand SSBs or not.
  • the parameter may be updated by the network at any time, e.g., based on the load of the network, the availability of resources, the mobility pattern of the UE, etc. In this way, the network can control how the delivery of on-demand SSBs is achieved.
  • an access device receiving a set of capabilities from the device, indicative that the device is an "indication-capable device"
  • the access device determines whether the indication-capable device works as an "indication-capable device” determining the distribution of on-demand SSBs or the network determines the distribution of on-demand SSBs, and the access device configures the indication-capable device to act as an indication- capable device or to receive on-demand SSBs as determined by the network.
  • a method for a first device comprising, the first device signalling to an access device in its capabilities that the first device is an "indication-capable device", the first device receiving a set of configuration, configuring the first device to act as an indication-capable device and/or to receive on-demand SSBs.
  • a cell may provide a UE with the parameters of an on-demand pilot signal that it has determined and an indication-capable UE may also request on-demand pilot signal according to its own preferences.
  • a UE may signal that it is an indication-capable device, and an access device may, in that case, provide the UE with parameters that allow the UE to signal its request to receive on-demand pilot signals (e.g., SSBs).
  • Such parameters may be one or more specific preambles (PRACH) that needs to be transmitted to a cell, e.g., primary cell, to receive on-demand pilot signals from a cell, e.g., secondary cell.
  • PRACH specific preambles
  • the on-demand pilot signals that are transmitted may depend on the indication that is transmitted by the UE. For instance, which on-demand pilot signals are requested may be indicated by the usage of a specific preamble. Other parameters related to which on-demand pilot signals are (going to be) distributed, however, may have been preconfigured by an access device in the UE. For instance, an access device may provide a UE with a configuration indicating the timing of the on-demand pilot signals once the UE has sent its indication/request to receive on-demand pilot signals. For instance, it may indicate that a number of on-demand SSB bursts will be transmitted with a given periodicity and specific transmission parameters (e.g., specific transmission power).
  • the configuration may comprise, e.g, k entries as follows:
  • Above configuration may also include other parameters, e.g., the indixes of the on- demand pilot signals, e.g., the indexes of the SSBs that will be transmitted.
  • the indication to receive on-demand pilot signals may be an indication to multiple access devices. This allows a UE to send a single message, and receive on-demand pilot signals from multiple access device to select the most suitable cell. Such an indication may have been received in a previous configuration from a cell (e.g., primary cell), or may be based on a flag included in the on-demand pilot signal request message. Upon reception of such a request, cells addressed by the indication may provide on-demand pilot signals. Cells may also interact with each other to determine which cell may be the most suitable one, so that only the cell that is considered / determined to be the most suitable one delivers the on-demand pilot signals allowing the UE to select the cell and/or synchronize.
  • a cell e.g., primary cell
  • cells addressed by the indication may provide on-demand pilot signals. Cells may also interact with each other to determine which cell may be the most suitable one, so that only the cell that is considered / determined to be the most suitable one delivers the on-demand pilot signals allowing the UE to select the
  • the (target or source) access device may compute the timing advance of the UE (since it knows the location of the UE that is joining and the location of the access device). It is to be noted that in 5G, the TA value field in the second RACH message is 12 bits long while the TA value field in the MAC CE element is only 6 bits long because it is only used to update/correct the TA value. Since the (target) access device knows the rough location of the UE, and thus, rough timing advance, the (target) access device may communicate this information to the UE so that the UE can start using this information. For the same reason, the TA value field in the RACH procedure can be shorter than 12 bits when a UE is using on-demand pilot signals.
  • the TA value field in the RACH procedure may be just 6 bits long.
  • a source access device may request a target access device to activate certain cells/SSBs, e.g., similar to TDoc R3-235073 whereby: if the NR Cells and SSBs List IE is included by the source access device in the CELL ACTIVATION REQUEST message, the target access device shall, if supported, only activate the SSB beams indicated by the SSBs to be Activated List IE if included. If the SSBs to be Activated List IE associated with the cell indicated by the NG CGI IE is not included, the target access device shall, if supported, activate all the inactive SSB beams in the cell.
  • SSBs e.g., similar to TDoc R3-235073 whereby: if the NR Cells and SSBs List IE is included by the source access device in the CELL ACTIVATION REQUEST message, the target access device shall, if supported, only activate the SSB beams indicated by the SSBs to be Activ
  • the target access device includes the NR SSBs Activated List IE in the CELL ACTIVATION RESPONSE message.
  • the source access device shall consider the SSB beams indicated by the NR SSBs Activated List IE as activated.
  • a (source) access device may request a (target) access device to activate or deactivate certain beams or transmit certain (on-demand) pilot signals with a given timing or at a given location or under a given condition complementing the information exchanged in the CELL_ACTIVATION REQUEST and RESPONSE messages. This may be needed, e.g., when a UE is moving from the (source) access device to the (target) access device or when the (target) access device is going to provide further resources. For instance,
  • the (location) it may request to activate/deactivate beams/SSBs/transmission of pilot signals at a given location or area or volume.
  • the (source) access device may not always know, e.g., the SSB identifiers, used by a (target) access device, e.g., because the (target) access device may be mobile, and this SSB/beam information may be unknown. This may be the case when dealing mobile access devices such as UAV or satellites, in particular, because their orientation can change, and their location can change,
  • timing it may request to activate/deactivate beams/SSBs/transmission of on-demand or regular pilot signals for a given period of time, e.g., for a time window of, e.g., 80 ms, or 160 ms, or 320 ms.
  • the (target) access device may switch off/on again those beams/SSBs, in general, stop/start transmitting the pilot signals. This is advantageous because it limits the need to send a second message, and makes sure that the previous operation/performance is restored,
  • the (source) access device may transmit a condition so that the (target) access device may transmit/stop transmitting the (on demand or regular pilot signals until the condition happens, e.g., a UE connects as enabled by the transmitted on demand pilot signals). For instance, if a UE connects to a (target) access device as enabled by an on-demand beam/SSB whose activation was requested by a (source) access device, the (target) access device may disable said beam/SSB.
  • This information may be exchanged over an interface, e.g., the Xn or Fl interface. It is to be noted that it is advantageous when the (source) access device indicates to the (target) access device about the specific location/timing/condition since it allows for a more stand alone operation of the (target) access device compared with a baseline solution in which the (source) access device only indicates to the (target) access device the beams/SSBs to activate/deactivate.
  • the source and target access device may need to previously exchange or be configured with the SSB/beam configuration that is used, e.g., which SSBs/beams are used to cover which area/volume.
  • the (target) access device may inform a (source) access device about the pilot signals that are currently active, the time they will remain active, and/or the reason thereof. For instance, if a (target) access device has detected a UE (e.g., by means of wireless sensing) at a given location, it may take the decision of activate on-demand pilot signals in that area, and it may then inform a close by source access device about this activation. This information may be exchanged over an interface, e.g., the Xn interface.
  • the on-demand pilot signal (e.g, MIB itself or SIB1) may include the estimated TA for the UE. This allows informing the UE about its (rough) TA even before the UE performs the random-access procedure. This is feasible because the access device may sense/retrieve the position of the UE, and the gNB may obtain said TA estimate. This is feasible because the on-demand pilot signals may be focused to specific areas wherein all Ues may share a similar TA.
  • the UE may be able to use a random access method such as slotted aloha for improved access.
  • a random access method such as slotted aloha for improved access. The reason is that the UEs may be able to estimate when to send the PRACH so that it is received within a slot of the Slotted Aloha multiple access procedure.
  • the (target) access device may be a satellite or connect to the UE via a transparent satellite.
  • the timing advance can be a quite big value.
  • the continuous transmission of pilot signals may lead to a high energy consumption.
  • This use case/scenario can benefit of the different embodiments in this invention because it allows the (target) access device to provide pilot signals on demand specific to a given area, informing the UEs about the timing of the pilot signals, and avoiding the usage of large TA value fields.
  • the (source) access device may be a terrestrial access device that communicates with the non-terrestrial access device indicating the location of the UE.
  • the non-terrestrial access device or the access device communicating through a non-terrestrial device, to determine the timing of the pilot signals focusing on the area where the UE is located.
  • the UE is informed (e.g., via the source access device) about the timing advance value to use with the (target) access device when connecting to it.
  • the (target) access device may transmit the (on demand) pilot signals at any time, with any periodicity or timing constrains.
  • the target access device may inform the UE (e.g., via the source access device) that it only needs to acquire the on-demand SSB pilot signals (e.g., for exact beam alignment) and skip the RACH messages requesting the UE to send directly as initial message the RRC Setup Complete message.
  • the UE e.g., via the source access device
  • the target access device may inform the UE (e.g., via the source access device) that it only needs to acquire the on-demand SSB pilot signals (e.g., for exact beam alignment) and skip the RACH messages requesting the UE to send directly as initial message the RRC Setup Complete message.
  • the target access device may allocate/inform the UE (via the source access device parameters that are usually received in SIB1, message 2 and 4 of the RACH, e.g., srb-ToAddModList, masterCellGroup ⁇ cellGroupId, rlc- BearerToAddModList, mac-CellGroupConfig, physicalCellGroupConfig ⁇ ). Furthermore, the UE informs via the source access device about parameters that are usually exchanged in message 1 and 3 of RACH, e.g., establishment cause.
  • the target access device may also perform resource allocation based on the location / mobility pattern of the UE, and inform about the resource allocation (timing, frequency,...) to transmit the initial RRC Setup Complete message (initial in this invention embodiment).
  • the target access device or source access device may also inform the UE about the timing advance value (which can be computed because/if source/target access devices) know the location of the UE. The UE uses this timing advance to accurately send the initial RRC Setup Complete.
  • the on-demand pilot signals need to be/are distributed to the UE, and the UE needs to inform target access device about its choice (i.e., the selection of a given target access device).
  • This informative step is done through the source access device, instead of by means of a random-access procedure.
  • the UE receives the on-demand pilot signals, it informs the source UE about its reception/measurement, and the source UE may inform the target UE of it. This is advantageous since it limits additional control signaling between UE and (target) access device
  • the UE may need to include the signal strength, as well as other parameters such as frequency shift, estimated distance, etc. of the on-demand pilot signals in the first message transmitted to the gNB, e.g., RRC Setup Complete, so that the gNB can perform beam alignment.
  • the embodiment (variants) presented in this invention may be applicable enable a Secondary Cell (SCell) to reduce the energy consumption by limiting the number of SSBs that need to be distributed.
  • SCell Secondary Cell
  • the scenario is a "PCell/SCell" scenario whereby a UE may be connected to a primary Cell (PCell) that serves as the main point of communication between the user device and the base station. It provides a stable and reliable connection, it allows exchange of control information, high bandwidth and low latency. Then a SCell can be established to enhance network performance and provide additional bandwidth when needed.
  • the SCells can be dynamic and added/removed based on network conditions; it can provide additional bandwidth or specialized services.
  • the PCell may know the location of the UE, or when a given UE requires the broadcasting of pilot signals such as SSBs from the SCell so that the PCell may require a SCell to broadcast pilot signals/SSBs on demand in the area where the UE is located to facilitate the connection to the SCell without requiring a high energy consumption.
  • Secondary cells are used, e.g., when using carrier aggregation wherein different cells provide data through different carriers that may be intra band contiguous, intra band non-contiguous or inter band contiguous.
  • the PCell and the SCell may coordinate themselves by exchanging data (e.g., condition triggering the on-demand broadcast of pilot signals such as SSBs) through the Xn data interface.
  • the main node (MN, 802) i.e., PCell
  • the secondary node (SN, 804) i.e., SCell about the location of the UE and/or UE as a condition triggering the broadcasting of the pilot signals, e.g., on-demand pilot signals.
  • the SN should tell MN about the type of pilot signals used, e.g., on demand pilot signals, as well as any other parameters that the SN may estimate or use (e.g., estimated TA, or timing of the on-demand pilot signals, or number of on-demand pilot signals, as in other embodiments, etc).
  • the MN informs the UE about such configurations, i.e., it informs the UE 801 by means of an RRC message, in this case, RRCConnectionreconfiguration message.
  • the MN may not inform the SN about the location of the UE, but may configure the UE to send an indication that when received by the SN triggers the distribution of on demand pilot signals.
  • the message flow is similar to Fig. 13, except that the UE sends a message to the SN via the local wireless interface indicating that it wants to receive the reference signals from the access device.
  • the UE can then synchronize with the access device using the on-demand pilot signals.
  • This embodiment may reduce the signaling overhead between the MN and the SN, as well as allow the UE to have more control over the synchronization process.
  • Fig. 14 describes a further scenario relevant for another aspect of the invention.
  • the scenario of Fig. 14 considers two UEs 901 and 902 connected through a local wireless connection (e.g., PC5 interface) and access device 903.
  • UE 901 may be a Remote UE and UE 902 may be a UE to Network relay.
  • UE 901 may be out of coverage or may not be searching for access devices actively to save energy.
  • UE 902 may receive in message 904 reference signals such as SSBs or SIB1 or another SIB from access device 903.
  • UE 902 may announce or distribute the information of the access device in message 905 to UE 901.
  • UE 901 may send a message to UE 902 a request in message 906 requesting the "on-demand distribution" of the reference/pilot signals of the access device. Such a request may then be shared with access device 903 in message 907. Access device 903 may then share information with UE 902 about the timing/frequency of the reference/pilot signals in message 908, that is further shared with UE 901 in message 909 via the local wireless interface. Finally, the (on-demand) reference/pilot signals are distributed in message 910 according to the timing/frequency resources allocated and distributed in messages 908 and 909 so that UE 901 can directly (via the Uu interface) access said reference/pilot signals.
  • This message flow supports an embodiment of the invention that may be combined with other embodiments or used independently in which UE 902 performs the selection of the access device 903 on behalf of device 901 whereby UE 902 may announce, e.g., in message 905, the selected access device 903 as well as the measurements (e.g, signal strength of the received SSBs from access device 903) performed when making this selection.
  • This information may be used by device 901 to determine whether to further connect to access device (e.g, 903) through 902 or directly.
  • This information may also be used by device 901 to acquire synchronization signals/system information of access device 903 in a better way (e.g., faster or more efficiently) because the timing of the signals in message 910 has been made know previously in messages 908 and 909.
  • This can also allow the access device to regulate the signal strength of its reference/pilot signals (e.g., SSBs) so that UE 901 may receive them directly.
  • An exemplary use case of this technology is the connection to an access devices of two UEs, where one of the UEs is considered the main one (e.g., a smart phone) and another UE is considered the secondary one (e.g., a smart watch).
  • the smart watch usually connects through the main UE, and it uses the main UE to obtain reference signals on demand.
  • This embodiment may be applicable to different procedures in, e.g., TS 38.331.
  • Clause 5.8.6.3 (Sidelink communication transmission reference cell selection) may be enhanced so that UE 901 can better receive synchronization signals from the selected reference cell.
  • UE 901 or 902 may inform about the selection (e.g., in message 907) so that the reference/pilot signal can be distributed (on demand) in step 910 (and reach UE 901 and achieve the corresponding synchronization).
  • This procedure may be similar to Clause 5.8.9.8.3 but focused on the distribution of reference signals such as synchronization signals.
  • the ideas in this invention may be applied to enable improved connectivity through mobile access devices such as a vehicle-mounted base station, a vehiclemounted reflective intelligent surface, a vehicle-mounted smart repeater, etc where the vehicle may be a terrestrial vehicle such as a bus, car, or train or aerial vehicle such as a drone or an Unmanned Aerial Vehicle (UAV) or a plane or a satellite.
  • the vehicle may change its location and it may be desirable to deliver SSBs / beams to a UE or another mobile access device through said vehicle on demand.
  • the on-demand pilot signals are transmitted based on the speed or location of the mobile access device.
  • the embodiments in this invention may be applied to enable improved connectivity to a second UE through a first UE whereby the first UE acts as a smart repeater rebroadcasting the pilot signals received from an access device.
  • the first UE may be able to sense the location of the second UE so that the first UE only retransmits/rebroadcasts certain pilot signals.
  • a smart repeater may request the SSBs from a base station on demand, e.g, when the smart repeater serves as a range extender, depending on its own needs and the channel conditions or number of UEs detected in close environment. For example, if the smart repeater detects that there are no UEs in its vicinity, it may not need to rebroadcast the SSBs and may save power and bandwidth by not requesting them. On the other hand, if the smart repeater senses that there are UEs nearby that need to connect to the network, it may request the SSBs more frequently and retransmit them to the UEs. This way, the on-demand pilot signals can enable more efficient and flexible connectivity through the mobile access device.
  • the UE part of a smart repeater may determine the presence of UEs, e.g., by receiving signals from them, e.g., sidelink signals, or PRACH, etc.
  • the smart repeater may indicate to the base station that pilot signals should be transmitted on demand, e.g., by using the smart repeater UE to transmit a command to the base station.
  • Wi-Fi is a wireless technology that allows devices to connect to the Internet or to each other without using cables. Wi-Fi is based on radio waves that are transmitted and received by a device called a wireless access point (AP).
  • the AP acts as a hub that connects Wi-Fi enabled devices, such as laptops, smartphones, tablets, smart TVs, etc., to a wired network, such as a local area network (LAN) or the Internet.
  • LAN local area network
  • Wi-Fi is a trademark of the Wi-Fi Alliance, an industry association that certifies products that comply with the IEEE 802.11 standards for wireless local area networks (WLANs). These standards define the physical and data link layers of the communication protocol, such as the frequency bands, modulation schemes, encryption methods, authentication mechanisms, and data rates used by Wi-Fi devices.
  • Wi-Fi The most common Wi-Fi standards are 802.11a, 802.11b, 802.11g, 802. lln, 802.11ac, and 802.11ax, which operate in different frequency bands (2.4 GHz, 5 GHz, or both) and offer different levels of performance and compatibility.
  • a device needs to have a wireless network interface card (NIC) that can send and receive radio signals.
  • the NIC scans the available wireless channels and detects the presence of nearby APs.
  • the device selects an AP to connect to, based on factors such as signal strength, security settings, and network name (SSID).
  • the device and the AP exchange information, such as the MAC address, IP address, encryption key, and password, to establish a connection. This process is called association.
  • the device can communicate with the AP and other devices on the same network, or access the Internet through the AP.
  • IEEE 802. lln Wi-Fi 4
  • IEEE 802.11ac Wi-Fi 5
  • IEEE 802.11 ax WIFI-6
  • IEEE 802.11 ah introduced target wake time (TWT) to support low power loT applications by allowing STAs to go into sleep when not in a wake period after negotiation with AP.
  • IEEE 802.11be Wi-Fi 7 aims at improving throughput and latency operating in unlicensed bands between 1GHz and 7.125 GHz. Wi-Fi 7.
  • Wi-FI 7 also enables multiple resource units to be assigned to a single device. Furthermore, it includes an enhanced preamble with a universal SIG filed indicating the PHY version. It also extends the negotiated ack buffer size to 1024 bits.lt also enables multilink operation (MLO) enabling multiple links between a station and an access point, for instance an AP can have two radios 2.4 and 5 GHz and use both of them for simultaneous transmission and/or reception with a multi-link capable device (MLD) capable station.
  • MLO multilink operation
  • Wi-Fi 7 also includes a restricted TWT providing predictable latency by assigning STAs to different rTWT types and making sure that other STAs do not transmit if they do not belong to a given rTWT type.
  • Wi-Fi 7 also include multi-AP coordination performing, e.g., coordinated transmission, beamforming, or joint transmission.
  • devices 100, 101 and 102 can be Wi-FI access points and device 106 can be a wireless station.
  • Station 106 and access point 101 are MLD and communicate with two links 126.
  • Device 102 is a cellular capable residential gateway.
  • a cellular system is a wireless communication system that consists of three main components: user equipment (UE), radio access network (RAN), and core network (CN). These components work together to provide voice and data services to mobile users over a large geographic area.
  • UE user equipment
  • RAN radio access network
  • CN core network
  • UICC universal integrated circuit card
  • SUPI subscription permanent identifier
  • a transceiver which converts the digital signals from the processor into analog signals for transmission and reception over the air interface.
  • the transceiver also performs modulation, demodulation, coding, decoding, and other signal processing functions.
  • a processor which controls the operation of the UE and executes the applications and services that the user requests.
  • the processor also communicates with the RAN and the CN using various protocols.
  • a display which shows the user the information and feedback from the UE, such as the signal strength, the battery level, the call status, the messages, the contacts, the menu, etc.
  • a microphone and a speaker which enable the user to make and receive voice calls, as well as use other audio features, such as voice mail, voice recognition, etc.
  • a keyboard and/or a touch screen which allow the user to enter and select commands, text, numbers, etc.
  • a camera and/or a video recorder which enable the user to capture and send images and videos, as well as use other multimedia features, such as video calling, video streaming, etc.
  • - A memory which stores the data and programs that the user needs, such as the phone book, the messages, the photos, the videos, the applications, etc as well as a computer program to perform the operations of the RAN and CN protocols.
  • a battery which provides the power supply for the UE.
  • Fig. 2 provides a schematic representation of a UE and its components, e.g., UICC (201), processor (202), transceiver (203), memory (204), input devices (205) such as camera, microphone, etc and output devices (206) such as display, speaker, etc.
  • UICC UICC
  • processor 202
  • transceiver 203
  • memory 204
  • input devices 205)
  • output devices 206)
  • display speaker, etc.
  • a UE access the cellular network via the radio access network, as described below.
  • Certain UEs may communicate with each other by using device-to-device communication, also known as sidelink communication using the PC5 interface that may rely on physical sidelink (PS) broadcast channel, PS shared channel, PS control, etc.
  • PS physical sidelink
  • a UE may receive a configuration by means of different procedures:
  • Downlink control information is a type of control information that is sent from the BS to the UE on the physical downlink control channel (PDCCH).
  • DCI contains various parameters that instruct the UE how/when to decode and transmit data on the physical downlink shared channel (PDSCH) and the physical uplink shared channel (PUSCH), such as the resource allocation, the modulation and coding scheme.
  • the UE needs to monitor the PDCCH in each subframe to detect and decode the DCI that is addressed to it.
  • Uplink control information is a type of control information that is sent from the UE to the BS on the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH).
  • UCI contains various feedback signals that inform the BS about the status and quality of the downlink transmission, such as the HARQ. acknowledgments (ACKs), the channel state information (CSI), and the scheduling requests (SRs).
  • ACKs acknowledgments
  • CSI channel state information
  • SRs scheduling requests
  • the UE needs to encode and transmit the UCI according to the configuration and timing indicated by the BS.
  • SCI Sidelink control information
  • PSCCH physical sidelink control channel
  • D2D device-to-device
  • the main functions of SCI include resource allocation, synchronization, channel quality reporting, .
  • MAC CE Medium access control control element
  • BSR buffer status report
  • TAC timing advance command
  • DRX discontinuous reception
  • the UE needs to process the MAC CE according to the MAC protocol and the configuration provided by the BS.
  • Radio resource control (RRC) command is a type of control information that is exchanged between the BS and the UE on the RRC layer.
  • RRC Command contains various messages that modify/configure RRC parameters and/or initiate, modify, or release the RRC connection or the radio bearers between the UE and the BS, such as the RRC connection setup, the RRC connection reconfiguration, the RRC connection release, the security mode command, the mobility from E-UTRA command, the handover from E-UTRA preparation request, etc.
  • the UE needs to respond to the RRC Command according to the RRC protocol and the configuration provided by the BS.
  • Non-access stratum (NAS) messages are used for signalling between UE and core network (CN) on the non-access stratum (NAS) layer.
  • NAS messages enable functionality such as registration, session establishment, security, and mobility management.
  • the UE needs to respond to the NAS Command according to the NAS protocol and the configuration provided by the CN.
  • UE parameter update is a procedure between the UE and the home network that enables the home network to update configuration parameters in mobile phones and/or USIM using tthe UDM control plane procedure (TS 23.502).
  • the UE can receive Parameters Update Data from the UDM after the UE has registered in the 5G network.
  • SoR Steering of Roaming
  • SoR Steering of Roaming
  • UE user equipment
  • 3GPP TS.23.501 Release 15
  • 3GPP TS 24.501 Release 15
  • the 5G CP-SOR is activated during or after registration to update the UE's "Operator Controlled PLMN Selector with Access Technology" list via secure NAS messages, as directed by the home PLMN based on specific operator policies, such as preferred networks or UE location.
  • UE configuration update is used to update configuration parameters as per TS 23.502 that may include Access and Mobility Management related parameters decided and provided by the AMF, UE Policy provided by the PCF.
  • AMF wants to change the UE configuration for access and mobility management related parameters the AMF initiates the procedure defined in clause 4.2.4.2.
  • the PCF wants to change or provide new UE Policies in the UE, the PCF initiates the procedure defined in clause 4.2.4.3. If the UE Configuration Update procedure requires the UE to initiate a Registration procedure, the AMF indicates this to the UE explicitly.
  • the procedure in clause 4.2.4.2 may be triggered also when the AAA Server that performed Network Slice-Specific Authentication and Authorization for an S-NSSAI revokes the authorization.
  • Radio access network is the part of the cellular system that connects the UEs to the CN via the air interface.
  • the RAN consists of base stations (BSs).
  • a base station (BS) is a fixed or mobile transceiver that covers a certain geographic area, called a cell.
  • a BS is also called a gNB (next generation node B).
  • a BS can serve multiple UEs simultaneously within its cell, by using different frequencies, time slots, codes, or beams.
  • a BS also performs functions such as power control, handover control, channel allocation, interference management, etc.
  • a base station can be divided into two units: a central unit (CU) and a distributed unit (DU).
  • CU central unit
  • DU distributed unit
  • the CU performs the higher layer functions, such as RLC, PDCP, RRC, etc.
  • the DU performs the lower layer functions, such as PHY and MAC.
  • the CU and the DU can be co-located or separated, depending on the network architecture and deployment.
  • a base station may be denoted, based on context, as a cell, or gNB.
  • the cell may also refer to the coverage area of a base station.
  • a BS may have different coverage areas such as a macro cell (e.g. several kilometres wide), a pico cell (e.g., for a given location such as a stadium) or a femto cell for a small location (e.g., a home or part of it).
  • a base station may communicate with the core network. Since there can be base stations for different cellular systems, different interfaces are required. For instance, a base station, eNB, in a 4G Long Term Evolution (LTE) system (also known as Evolved Universal Mobile Telecommunications Systems (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the 4G CN known as EPC through the corresponding interface. For instance, a base station, gNB, in a 5G system (i.e., 5G New Radio or Next Generation RAN) may communicate with the 5GC through a different interface. 4G and 5G base stations may communicate with each other directly or through their corresponding core networks.
  • LTE Long Term Evolution
  • UMTS Evolved Universal Mobile Telecommunications Systems
  • 5G 5G New Radio or Next Generation RAN
  • the main protocols used between the UEs and the RAN are:
  • the physical layer which defines the characteristics of the air interface, such as the frequency bands, the modulation schemes, the coding rates, the frame structure, the synchronization, etc.
  • the medium access control (MAC) layer which regulates the access of the UEs to the shared radio channel, by using techniques such as orthogonal frequency division multiple access (OFDMA), time division duplex (TDD), frequency division duplex (FDD), etc.
  • OFDMA orthogonal frequency division multiple access
  • TDD time division duplex
  • FDD frequency division duplex
  • the radio link control (RLC) layer which provides reliable data transmission over the radio channel, by using techniques such as segmentation, reassembly, error detection, error correction, retransmission, etc.
  • the packet data convergence protocol (PDCP) layer which compresses and decompresses the headers of the data packets, encrypts and decrypts the data, and performs data integrity protection.
  • the radio resource control (RRC) layer which establishes, maintains, and releases the radio bearers between the UEs and the RAN, as well as exchanges the signaling messages for functions such as connection setup, handover, measurement reporting, security activation, etc.
  • RRC radio resource control
  • a transmission / reception communication unit or transceiver may be used by BS and UE to transmit / receive data.
  • Control data may be required for a physical broadcast channel, physical downlink control channel, etc.
  • Data may be for the physical downlink shared channel.
  • Data may be encoded by the UE and/or BS to obtain data symbols and/or control symbols that may be exchanged over the wireless interface.
  • the conversion from digital data into analog symbols may be done by the transmission / reception communication unit
  • a medium access control control-element is a MAC layer communication element that is used to control the communication between wireless devices.
  • a MAC-CE may be exchanged in a shared channel, e.g., the physical downlink / uplink / sidelink shared channel.
  • Reference signals may include primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel demodulation reference signal (DMRS), a channel state information reference signal (CSI-RS), a sounding reference signal (SRS), and a positioning reference signal (PRS).
  • PSS primary synchronization signal
  • SSS secondary synchronization signal
  • DMRS physical broadcast channel demodulation reference signal
  • CSI-RS channel state information reference signal
  • SRS sounding reference signal
  • PRS positioning reference signal
  • the PSS is essential for enabling User Equipment (UE) to detect and synchronize with a base station. It is transmitted in the downlink by the base station and helps UEs determine the cell identity and frame timing.
  • the PSS is crucial for initial cell search, as it allows the UE to identify the cell and acquire time and frequency synchronization with the network.
  • DMRS is used for channel estimation, which is necessary for coherent demodulation of data channels. It is transmitted in both uplink and downlink and allows the receiver to estimate the channel's characteristics and compensate for its effects on the transmitted signal.
  • DMRS provides support for MIMO: In Multiple Input Multiple Output (MIMO) systems, DMRS helps in distinguishing between signals from different antennas.
  • CSI-RS is specifically designed for providing channel state information, which is used for advanced receiver techniques and optimization of transmission parameters. It is primarily used in downlink and aids in precise channel quality measurements, aiding in adaptive modulation and coding. CSI-RS also assists in determining the optimal beamforming vectors for directional transmission, enhancing signal strength and coverage.
  • SRS is transmitted in the uplink by UEs and is used by the base station to obtain uplink channel quality information. It helps in uplink scheduling and link adaptation and efficient uplink resource allocation. It also enables the base station to adapt transmission parameters like modulation and coding schemes based on uplink channel quality.
  • PRS is designed for positioning and location-based services. It is transmitted in the downlink and aids in determining the UE's location with high accuracy.
  • Core network is the part of the cellular system that connects the RAN to other networks, such as the Internet, or other cellular systems.
  • the CN consists of two main (control/user) domains.
  • the control domain is responsible for providing signalling and control functions for the UEs, such as authentication, authorization, mobility management, session management, etc.
  • the control plane consists of several network functions (NFs), such as the access and mobility management function (AMF), the session management function (SMF), the unified data management (UDM), the policy control function (PCF), the network exposure function (NEF), and the authentication server function (AUSF).
  • the access and mobility management function is a NF that handles the registration, deregistration, connection management, and mobility management for the UEs.
  • the session management function is a NF that handles the establishment, modification, and release of the sessions for the UEs.
  • the SMF also communicates with the user plane devices to perform functions such as IP address allocation, tunneling, QoS, etc.
  • the unified data management (UDM) is a NF that stores and manages the user data, such as the SUPI, the service profile, the subscription status, etc.
  • the policy control function (PCF) is a NF that provides the policy rules and charging information for the UEs, such as the access type, the service level, the data rate, the quota, etc.
  • the network exposure function is a NF that exposes the network capabilities and services to external applications and devices, such as the IMS, the Internet of Things (loT), etc.
  • the authentication server function is a NF that performs the primary authentication with the by using credentials and the SUPI.
  • the user domain is responsible for providing data and multimedia services to the UEs, by using packets and IP addresses.
  • the user plane consists of two main functions: the user plane function (UPF) and the data network (DN).
  • the user plane function (UPF) is a device that forwards the data packets between the UEs and the DNs, as well as performs functions such as tunneling, firewall, QoS, charging, etc.
  • the data network (DN) is a network that provides access to the services and applications that the UEs request, such as the Internet, the IMS, etc.
  • a residential gateway is a device that connects a home network to an external network, such as the Internet or a cellular system.
  • An RG typically provides functions such as routing, switching, firewall, NAT, DHCP, DNS, VPN, etc.
  • An RG can also support various types of interfaces, such as Ethernet, Wi-Fi, Bluetooth, USB, etc.
  • a cellular-capable RG is an RG that has a cellular interface, such as a UICC slot, a cellular modem, or an antenna, that enables it to access the cellular system as a backup or an alternative to the wired or wireless broadband connection.
  • a cellular-capable RG can provide benefits such as: (1) Enhanced reliability, by switching to the cellular connection in case of a failure or a degradation of the broadband connection; (2) Increased bandwidth, by aggregating the cellular connection and the broadband connection to achieve higher data rates or QoS.
  • a multi-SIM subscription is a subscription that allows a user to have multiple SIMs (or eSIMs) that are linked to the same account and service profile.
  • a user can use the multi-SIM subscription to access the cellular system from different devices, such as a smartphone, a tablet, a laptop, or a wearable device, without having to switch the SIM card or the device.
  • devices 100, 102, and 128 can play the role of UEs.
  • Device 102 is part of a cellular-capable RG providing connectivity to a home network 129 e.g., by means of a local area network and/or wireless local area network.
  • Device 102 is served by base station 104.
  • the RAN 127 comprises base station 103 and serves UE 128.
  • UE 128 may also be a UE to Network relay given access to remote UE 136 that is out of coverage of base station 103.
  • UEs 134 and 136 also communicate with each other via a UE-to-UE relay 135.
  • the range of base station 103 is extended via smart repeater 137 and reflective intelligent surface (RIS) 138.
  • Smart repeater 137 and RIS 138 give access to UE 142.
  • the RAN 143 includes base station 104 and serves as wireless access infrastructure for the home network.
  • Base station 104 also serves a mobile access device and/or UE as a UAV 139.
  • UAV 139 may provide connectivity to remote UE 136.
  • a satellite gateway 141 is shown that connects to satellite 140 and may provide connectivity services to remote UE 136 or UE 100.
  • the 5G core network 133 may include one or more an AMF 121, SMF 123, UPF 122, AUSF 124, UDM 125, PCF 131, NEF 132 and allows the connection to a data network 130.
  • a second core network 142 e.g., a legacy core network as a 4G core network, is also shown that may interface with the 5G core network 133, interface with base stations denoted eNB in 4G, and provide a connection to the data network 130.
  • the legacy 4G core network is denoted EPC and may include one or more mobility management entities (MME), a serving gateway, a multimedia broadcast multicast service gateway, a broadcast multicast service center, a packet data network gateway, etc.
  • MME mobility management entities
  • the mobility management entity may handle the signalling between UE and the 4G CN and may interact with the home subscriber server (HSS) in charge of the storage and management of subscriber data and secrets.
  • HSS home subscriber server
  • the MME may provide connection management, similar to the AMF in 5G.
  • the serving gateway may be used to exchange user internet protocol messages whereby the serving gateway may interact with the packet data network gateway that is connected to IP services. Multiple protocols in 4G and 5G have similar features.
  • a UE may have a subscription with a home PLMN, and during the registration procedure, the (AMF of the) serving PLMN may forward the registration request to the (AUSF of the) home PLMN that may perform an initial authentication procedure between home PLMN and UE. If the authentication procedure is successful, keys are derived and the home PLMN may share derived credentials with the serving PLMN, including K_SEAF, that may be used to derive K_AMF, from which NAS keys and AS keys are derived.
  • K_SEAF Kermanent Access Management Function
  • the long-term subscriber's identifier known as Subscriber Permanent Identifier may not be exchanged in the clear, but instead, either a Subscription Concealed Identifier (SUCI) or a pseudonym known as GUTI are exchanged with the AMF of the serving PLMN.
  • the AMF of the PLMN may then forward the SUCI to the home PLMN so that the home PLMN decrypts/verifies it.
  • Fig. 1 depicts satellite 140 providing access to one or more UEs. Satellite access can be performed by means of non-terrestrial devices at different altitudes such as Low Earth Orbit (LEO), Medium Earth Orbit (MEO) or Geosynchronous Equatorial Orbit (GEO) satellites. Other types of nonterrestrial devices may include high-altitude platform station (HAPS) or unmanned aerial vehicle (UAVs) that may comprise a base station.
  • Fig. 3 illustrates different elements including a GEO satellite 302, a MEO satellite 303, a LEO satellites 304 and 304', a UAV 305, all of them potential non-terrestrial mobile access devices giving coverage to wireless device (e.g., a UE) 301.
  • wireless device e.g., a UE
  • GEO satellite 302 remains static over a given earth position while MEO and LEO satellites move.
  • MEO satellites 303 have a slower moving vector 306 in relation to the earth compared with LEO satellites 304 / 304' that have a faster moving vector 307 / 307'.
  • a non-terrestrial gateway 308 is included that provides connectivity to the mobile access device via a feeder link 310.
  • a mobile access device provides service to the wireless device via a service link 311. Two mobile access devices in the same orbit may communicate with each other via an intra-orbit-satellite link 312 while two mobile access devices in different orbits may communicate with each other via an inter-orbit-satellite link 313.
  • Fig. 3 finally also includes a terrestrial access device 309 that may also provide connectivity to wireless device 301.
  • the terrestrial access device 309, the wireless device 301, and non-terrestrial gateway are on the earth surface 314.
  • Non-terrestrial devices such as satellites distribute system information in specific SIBs, in particular, SIB31 in 4G and SIB19 in 5G.
  • S19 information element as defined in TS 38.331 18.2.0.
  • a UE in a cellular system performs an initial random-access procedure to connect an access device.
  • the 5G random access procedure is illustrated by means of Fig. 4 wherein 401 represents a user equipment and 402 represents an access device.
  • the access device distributes signals 402.
  • Signals 402 can be distributed periodically or on demand.
  • Signals 402 may comprise the Master Information Block (MIB) transmitted together with / in the physical broadcast channel (PBCH) and the synchronization signals.
  • MIB comprises:
  • MIB :: SEQUENCE ⁇ systemFrameNumber BIT STRING (SIZE (6)), subCarrierSpacingCommon ENUMERATED ⁇ scsl5or60, scs30orl20 ⁇ , ssb-SubcarrierOffset INTEGER (0..15), dmrs-TypeA-Position ENUMERATED ⁇ pos2, pos3 ⁇ , pdcch-ConfigSIBl INTEGER (0..255), cellBarred ENUMERATED ⁇ barred, notBarred ⁇ , intraFreqReselection ENUMERATED ⁇ allowed, notAllowed ⁇ , spare BIT STRING (SIZE (1))
  • MIB and PBCH are transmitted as part of a Synchronization Signal Block, and the access device may transmit multiple SSBs through different beams, allowing the user equipment to determine the preferred beam, and once the preferred beam is obtained, retrieve the MIB, and use the information in the MIB to attempt to retrieve System Information Block 1 (SIB1) that may also be distributed periodically.
  • SIB1 System Information Block 1
  • the UE can the use the information in SIB1 to perform the random-access procedure selecting a preamble to indicate its intention to access the cell by means of message 404, e.g., preamble transmission. This message may use a random-access radio network temporary identifier (RA-RNTI).
  • RA-RNTI random-access radio network temporary identifier
  • This message may include a time advance field to adapt the transmission timing, a value matching the preamble used by wireless device 401, and a grant (communication resources) for the wireless device.
  • the access device also assigns a temporary cell radio network temporary identifier (TC-RNTI).
  • TC-RNTI temporary cell radio network temporary identifier
  • the access device may send a PDCCH DCI message assigning resources (a communication grant). This message may be addressed using the RA-RNTI.
  • wireless device uses the initial grant received in the previous message and the RA-RNTI to transmit a subsequent message 406, e.g, an RRCSetupRequest or PHY layer.
  • This message may include a Contention Resolution Identifier (CRI). This message may be sent in the PUSCH.
  • CRI Contention Resolution Identifier
  • access device replies with message 407, e.g., RRCSetup, that includes / repeats the received CRI confirming that the access device has identified the access device.
  • This message includes a Cell RNTI (C-RNTI).
  • wireless device replies with message 408, e.g., an RRCSetupComplete that includes the RegistrationRequest message, and UE capabilities.
  • MIB and PBCH are transmitted as part of a Synchronization Signal Block, and the access device may transmit multiple SSBs through different beams. Multiple SSBs transmitted through multiple beams form an SSB burst. The multiple SSBs in an SSB burst are transmitted sequentially in the first part of a frame. SSB bursts are transmitted periodically, typically every 20 ms, or more.
  • Fig. 5 schematically illustrates an access device 500 transmitting four beams, each of them transmitting an SSB, namely 501, 502, 503, and 504.
  • a wireless device 505 can measure the signal strength, i.e., RSRP (Reference Signal Received Power), of the beams. This is illustrated by means of the graph in Fig.
  • RSRP Reference Signal Received Power
  • 501', 502', 503', and 504' represent the RSRP of beams 501, 502, 503, and 504, respectively, as measured by wireless device 505.
  • Wireless device 505 can use this information to determine which one of the beams is the preferred beam for further communication, e.g., to perform the random access procedure.
  • Fig. 7 further schematically illustrates SSB bursts transmitted periodically.
  • each SSB burst comprises four SSBs transmitted in the first part / half of every second frame.
  • frames are denoted as f, f+1, f+2, f+3,...A frame has a typical duration of 10 ms.
  • a wireless system may be used to transport data belonging to different types of applications such as Machine Type Communication (MTC), Critical Machine Type Communication (CMTC), Enhanced Mobile Broadband (EMB), or Fixed Wireless Access (FWA).
  • MTC e.g., smart meters, tracking,
  • CMTC e.g., industrial applications
  • EMB VR/AR, 4K UDH,
  • FWA FWA
  • 5G the Quality of Service has to accommodate different applications such as EMB, MTC, ultrareliable low latency communications.
  • QoS is influenced by the entities involved in the communication, UE, RAN, UPF, and DN. Data exchanges between UE and DN are mapped to QoS flows, and each QoS flow is mapped to a 5G QoS Identifier (5QI) in TS 23.501 (Table 5.7.4-1) that describes resource types, priority, packet delay budget, packet error rate, maximum data burst volume. Network is configured to configure RAN and core network interfaces to achieve the requirements of a 5QI. QoS is applied to a data stream from the wireless physical layer to the core network. Between RAN and UPF, QoS is applied in terms of a QoS flow. QoS in the RAN is managed by means of Data Radio Bearers (DRB).
  • DRB Data Radio Bearers
  • a QoS flow on core network side is created by means of a PDU session establishment accept.
  • the mapping between a QoS flow and a DRM is done by means of SDAP configuration in an RRC message (RRCSetup or RRCReconfiguration)
  • the indication or identifier that connects the whole QoS pipe is called QoS flow identifier.
  • Downlink traffic requires mapping IP messages and the QoS pipe, and this is done by the UPF.
  • the UPF checks (by means of a packet QoS assignment / detection rule) the packet information (source/destination/protocol/type of service/...) and directs the IP packet to a QoS flow.
  • the packet QoS assignment / detection rule is provided by SMF interacting with PCF.
  • the UE performs a similar task by applying QoS rules provided in NAS messages (e.g., PDU session establishment) by the SMF or are pre-configured/derived by the UE.
  • Discontinuous reception (DRX) in cellular networks such as 5G is in two types, Idle mode DRX and Connected mode DRX.
  • Idle mode DRX the UE wakes up to monitor for paging messages. If no paging message is detected, it sleeps further.
  • Connected DRX mode the UE enters in sleep mode periodically and during the sleep period the UE is not required to monitor the Physical Download Control Channel.
  • the access device configures the UE device with C-DRX parameters.
  • Connected DRX approach reduces energy consumption of the device because it does not require monitoring the PDCCH periodically and it also reduces the transmissions of CSI or SRS signals, that also has a positive effect in the network / access devices load.
  • a long DRX cycle consists of an on period and an off period.
  • the on duration is in terms of milliseconds.
  • the long DRC cycle may be configured or the long DRX cycle and short DRX cycles may be configured.
  • the access device can configure the time (drx-onDurationTimer) during which the UE is awake and goes back to sleep if there is no PDCCH received.
  • the access device can also configure a given drx-LongCycleStartOffiset to start to awake period at a subframe boundary and/or drx-SlotOffset relative to the subframe boundary.
  • the UE may remain awake some more time determined by the drx-lnactivityTimer. Furthermore, the access device can configure long DRX cycle together with additional DRX cycle which is shorter than long DRX cycle. Configurable parameters include the drx-ShortCycle (duration of the short cycle) and drx-ShortCycleTImer that determines how many short cycles before the device should apply.
  • the transmitted and received analogue chirp signals are mixed to generate an intermediate frequency (IF) signal which corresponds to the difference in frequencies of the two signals (outbound and inbound) and whose output phase corresponds to the difference in the phases of the two signals.
  • IF intermediate frequency
  • Each surface of a scene or environment will therefore produce a constant frequency IF signal whose frequency relates to the distance to the surface (i.e., a first distance from the transmitter of the chirp signal to the surface plus a second distance from the surface to the receiver of the chirp signal).
  • the two IF signals can be frequency resolved. A longer time window of the IF signal results in greater resolution.
  • the resolution of the radar is related to the chirp bandwidth.
  • the IF signal may then be band pass filtered (to remove signals below some minimal range and frequencies above the maximum frequency for a subsequent analogue-to-digital converter (ADC)) and digitized prior to further processing.
  • ADC analogue-to-digital converter
  • the upper frequency sensing range of the bandpass filter and ADC sets the maximum range that can be detected (i.e., IF frequencies increase with range).
  • the phase of the IF signal is important, since the phase (i.e., the difference in phases of the transmitted and received chirp signals) is a sensitive measure of small changes in the distance of a surface.
  • phase difference measures between two consecutive chirp signals can be used to determine the velocity of the surface.
  • a fast Fourier transform (FFT) processing can be performed across multiple chirp signals to enable separation of objects with the same range but moving at different velocities.
  • a Fourier transform converts a signal from a space or time domain into the frequency domain. In the frequency domain the signal is represented by a weighted sum of sine and cosine waves.
  • a discrete digital signal with N samples can be represented exactly by a sum of N waves.
  • FFT provides a faster way of computing a discrete Fourier transform by using the symmetry and repetition of waves to combine samples and reuse partial results. This method can save a huge amount of processing time, especially with real-world signals that can have many thousands or even millions of samples.
  • angle estimation can be performed by using the phase difference between the received chirp signal at two separated receivers.
  • the above-described wireless sensing techniques are implemented in a mobile communication system (e.g. 5G or 6G or other cellular or WiFi communication systems), while the functional coexistence of radar and communication operating in the same frequency bands is configured to avoid interference bandwidths.
  • a mobile communication system e.g. 5G or 6G or other cellular or WiFi communication systems
  • radio sensing can be integrated into large-scale mobile networks to create perceptive mobile networks.
  • the sensing signal may consist of a number of pulses sent, e.g., at specific frequencies and timing (sensing signal parameter information) by a sensing transmitter.
  • the sensing receiver may include a number of bandpass filters that allow identifying the sensing signal parameter information, e.g, timing and frequency of the received pulses.
  • the transmitter determines a given pseudo-random sequence of frequency/timing pulses and beams it, e.g., by means of beamforming, in a specific direction, and if the transmitter communicates to the receiver the timing/frequency, in general, the sensing signal parameter information, of the transmitted sensing signal, the receiver can use its bandpass filters to identify the reception of the same transmitted pulses, i.e., sensing signal, based on the received sensing signal parameter information.
  • the wireless sensing signal may be part of the synchronization signal block.
  • the wireless sensing signal may be a reference signal included in the primary synchronization signal or in the secondary synchronization signal. It may consist of a number of reference signals and/or it may be a wide band signal.
  • This wireless sensing signal can allow the access devices to determine the presence of a wireless device.
  • the wireless device may also use this wireless sensing signal to determine the access device that is more suitable to (re-)select.
  • this invention can be applied to various types of UEs or terminal devices, such as mobile phone, vital signs monitoring/telemetry devices, smartwatches, detectors, vehicles (for vehicle-to-vehicle (V2V) communication or more general vehicle-to-everything (V2X) communication), V2X devices, Internet of Things (loT) hubs, loT devices, including low-power medical sensors for health monitoring, medical (emergency) diagnosis and treatment devices, for hospital use or first-responder use, virtual reality (VR) headsets, etc.
  • V2V vehicle-to-vehicle
  • V2X vehicle-to-everything
  • LoT Internet of Things
  • loT devices including low-power medical sensors for health monitoring, medical (emergency) diagnosis and treatment devices, for hospital use or first-responder use, virtual reality (VR) headsets, etc.
  • the described operations like those indicated in the above embodiments may be implemented as program code means of a computer program and/or as dedicated hardware of the related network device or function, respectively.
  • the computer program may be stored and/or distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne des appareils, des procédés, et un système d'accès au réseau, les appareils et les procédés : a. déterminent ou obtiennent la présence ou l'emplacement d'un UE, b. déterminent un service requis par l'UE, c. sélectionnent les faisceaux et/ou le temps de transmission utilisés pour couvrir l'emplacement de l'UE, d. transmettent des signaux pilotes par l'intermédiaire des faisceaux déterminés ou obtenus, les signaux pilotes étant sélectionnés ou transmis pour permettre le service requis.
PCT/EP2024/077003 2023-10-09 2024-09-26 Procédé, appareil et système d'accès au réseau Pending WO2025078157A1 (fr)

Applications Claiming Priority (10)

Application Number Priority Date Filing Date Title
EP23202330.9 2023-10-09
EP23202330 2023-10-09
EP23214394 2023-12-05
EP23214394.1 2023-12-05
EP24152700 2024-01-18
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CN114900845B (zh) * 2022-05-31 2023-07-21 吉林大学 一种nr下基于覆盖环境和信道质量的波束管理方法
WO2023151463A1 (fr) * 2022-02-09 2023-08-17 Mediatek Inc. Procédé et appareil d'utilisation d'un signal de référence ou d'un bloc d'informations de système à la demande pour une économie d'énergie de réseau

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WO2023151463A1 (fr) * 2022-02-09 2023-08-17 Mediatek Inc. Procédé et appareil d'utilisation d'un signal de référence ou d'un bloc d'informations de système à la demande pour une économie d'énergie de réseau
CN114900845B (zh) * 2022-05-31 2023-07-21 吉林大学 一种nr下基于覆盖环境和信道质量的波束管理方法

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