HK1234245B - System detection in a high frequency band radio access technology architecture - Google Patents

Description

System testing in high-band radio access technology architectures

Related applications

This application claims the benefit of U.S. Provisional Patent Application No. 62/035,807, filed August 11, 2014, the contents of which are incorporated by reference as if set forth herein.

Background Art

As data-intensive services (e.g., music and movie streaming, three-dimensional content streaming, virtual reality experiences, etc.) become more and more part of society, the demand for high-bandwidth, low-latency data transmission increases. Wireless networks (e.g., cellular telecommunication networks) can utilize a variety of different radio access technologies ("RATs"), each of which can have different advantages and disadvantages. For example, fifth-generation ("5G") RATs can be viewed as high-frequency band ("HFB") RATs (e.g., can correspond to a higher frequency band than fourth-generation ("4G") RATs). 5G RATs can provide a higher level of performance (e.g., lower latency and/or higher throughput) than 4G RATs, but may have a smaller coverage area than 4G RATs.

One possible solution to the aforementioned shortcomings of the HFB RAT is to deploy multiple HFB RAT "small cells" to provide enhanced HFB RAT coverage. To utilize the HFB RAT, a user equipment ("UE"), such as a cellular phone, typically needs to detect one or more small cells. Small cell detection can be an inefficient process in terms of UE power consumption, radio resource utilization, and/or latency.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. For ease of description, similar reference numerals may represent similar structural elements. The embodiments of the present invention are shown in the accompanying drawings by way of example and not limitation.

1A , 1B , and 2 - 4 conceptually illustrate an overview of one or more implementations described herein;

FIG5 is an illustration of an example environment in which the systems and/or methods described herein may be implemented;

FIG6 illustrates an example process for detecting one or more small cells according to one or more implementations described herein;

FIG7 illustrates an example polling channel format that may be used by a UE when polling for a small cell according to some implementations described herein;

FIG8 illustrates efficient use of time-frequency resources by a cluster of small cells and/or transmission points according to some implementations described herein;

FIG9 illustrates frequency division multiplexing ("FDM") that may be used to efficiently utilize time-frequency resources when providing synchronization signals to UEs according to some implementations described herein; and

10 is a diagram of example components of a device.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings. The same reference numerals in different figures may identify the same or similar elements. It should be understood that other embodiments may be used and structural and logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be considered limiting, and the scope of the embodiments according to the present invention is defined by the appended claims and their equivalents.

In one implementation, a UE apparatus may include: a radio component for connecting to a wireless telecommunications network; a memory device for storing a processor-executable instruction set; and a processing circuit for executing the processor-executable instruction set, wherein executing the processor-executable instruction set causes the UE to: receive auxiliary information, the auxiliary information including at least one of the following: a carrier frequency and one or more cell identifiers associated with the wireless telecommunications network, a polling channel configuration, or a polling response channel configuration; generate a polling signal based on the auxiliary information; output the generated polling signal via the radio component; receive a synchronization signal in response to the polling signal, the synchronization signal being received via the radio component from one or more cells in the wireless telecommunications network; and use the information included in the synchronization signal to detect (and ultimately connect to) a specific cell among the one or more cells in the wireless telecommunications network.

The assistance information may include a carrier frequency associated with the wireless telecommunications network, and outputting the polling signal may include outputting the polling signal based on the carrier frequency. The assistance information includes the polling channel configuration, and outputting the polling signal may include outputting the polling signal according to the polling channel configuration. The polling response channel configuration may include an indication of at least one of the following: a time-frequency resource allocation, or a set of synchronization signal sequences. In some implementations, the UE may determine one or more parameters associated with the polling signal based on the radio access technology via which the assistance information is received. The one or more parameters determined based on the radio access technology via which the assistance information is received may include at least one of the following: a guard time period associated with the polling signal, or a cyclic prefix period associated with the polling signal.

In some implementations, assuming that the radio component is a first radio component associated with a first radio access technology, and the UE further includes a second radio component associated with a second radio access technology different from the first radio access technology, the assistance information may be received via the first radio component. In some implementations, the assistance information may be received via the second radio component.

In some implementations, outputting the polling signal may include outputting the polling signal in an omnidirectional, pseudo-omnidirectional, or directional pattern. The wireless telecommunications network may include: one or more base stations operating in a frequency band associated with a long-term evolution standard; and one or more small cells operating in a frequency band higher than the frequency band associated with the long-term evolution standard, and the one or more base stations may be synchronized with the one or more small cells. In some implementations, the assistance information may include spatial information, and outputting the polling signal may include beamforming the polling signal based on the spatial information.

In some implementations, the timing of transmitting the polling signal may be based on the timing of another wireless communication system. The timing of transmitting the polling signal may be determined by applying a timing advance based on the timing of the other wireless communication system, and the timing advance may be determined based on a value provided by the other wireless communication system.

A set of transmit beamforming weights associated with the received synchronization signal may be based on a set of receive beamforming weights associated with the polling signal. The polling channel configuration may include at least one of: a selected polling channel format, a time-frequency resource allocation, a parameter for transmit power control, or a preamble sequence. The parameter for transmit power control includes at least one of: an initial transmit power, a power ramping amount, a parameter related to setting a configured maximum output power, or a number of transmissions required before transmitting using the configured maximum output power. The UE may use multiple different antenna modes to sequentially send multiple polling sequences, where a first polling sequence is separated from a second polling sequence by a guard time.

In another implementation, a cell device in a wireless telecommunications network may include: a radio component for communicating with a UE; a memory device for storing a processor-executable instruction set; and a processing circuit for executing the processor-executable instruction set, wherein executing the processor-executable instruction set causes the cell device to: output auxiliary information to the UE, the auxiliary information may include at least one of the following: a carrier frequency associated with the wireless telecommunications network, a polling channel configuration, or a polling response channel configuration; receive a polling signal generated by the UE based on the auxiliary information from the UE; generate a synchronization signal for the UE, the generation including: determining one or more beamforming weights based on the received polling signal; and outputting the generated synchronization signal to the UE via a polling response channel in response to the polling signal, the polling response channel corresponding to the polling response channel configuration.

The cell device may operate on a frequency band higher than the frequency band in which the LTE base station network operates. The cell device may be synchronized with one or more LTE base stations. The auxiliary information may include a carrier frequency associated with the wireless telecommunications network, and the polling signal may be received on a carrier frequency associated with the wireless telecommunications network. The cell device may determine one or more transmission points (from which the synchronization signal is output via the polling response channel), the determination being based on at least one of the following: the signal strength of the received polling signal, the signal power (at which the received polling signal is sent by the UE), the receive timing offset of the received polling signal, or the load condition of the wireless telecommunications network. The auxiliary information may also include a cell identifier of the cell device. The beamforming weight may be determined based on at least one of the following: a beamforming weight associated with the received polling signal, or a set of beamforming weights. The polling channel configuration may include at least one of the following: a polling channel format, a time-frequency resource allocation, a parameter for transmission power control, or a preamble sequence. Parameters used for transmit power control may include at least one of: an initial transmit power, a power ramp-up amount, a parameter related to setting a configured maximum output power, or a required number of transmissions before transmitting using the configured maximum output power.

In another implementation, a method may include: receiving, by a wireless telecommunications network, a polling signal from a UE; and outputting, from a plurality of transmission points in the wireless telecommunications network, a plurality of synchronization signals to a plurality of UEs, wherein a first synchronization signal for a first UE from a first transmission point is associated with a first set of beamforming weights, wherein a second synchronization signal for the first UE from a second transmission point is associated with a second set of beamforming weights different from the first set of beamforming weights, wherein the first synchronization signal and the second synchronization signal for the first UE are transmitted on the same time-frequency resource, wherein outputting the plurality of synchronization signals includes: multiplexing the plurality of synchronization signals associated with different analog beamforming weights in the frequency domain. The synchronization signal for the first UE associated with the first set of analog beamforming weights may be output from a specific transmission point in a first frequency subdomain, and the synchronization signal for the second UE associated with the second set of analog beamforming weights may be output from another transmission point in a second frequency subdomain, the first subdomain and the second subdomain being different.

The transmission point may operate at a frequency band higher than a frequency band that the long term evolution base station operates in. The first synchronization signal and the second synchronization signal may be simultaneously output by the first transmission point and the second transmission point, respectively.

In another implementation, a UE may include: a device for receiving auxiliary information, the auxiliary information may include at least one of the following: a carrier frequency or a polling channel configuration associated with the wireless telecommunications network; a device for generating a polling signal based on the auxiliary information; a device for outputting the generated polling signal; a device for receiving a synchronization signal in response to the polling signal, the response being received from one or more cells in the wireless telecommunications network; and a device for using information included in the synchronization signal to detect a specific cell among the one or more cells in the wireless telecommunications network.

The assistance information may include a carrier frequency associated with the wireless telecommunications network, and outputting the polling signal may include outputting the polling signal based on the carrier frequency. The assistance information may include the polling channel configuration, and outputting the polling signal may include outputting the polling signal according to the polling channel configuration. The polling channel configuration may include an indication of at least one of the following: a cyclic prefix period, or a guard time period. The UE may also include means for determining one or more parameters associated with the polling signal based on the radio access technology via which the assistance information is received.

The parameter determined based on the radio access technology via which the assistance information is received may include at least one of the following: a guard time period associated with the polling signal, or a cyclic prefix period associated with the polling signal. The UE may also include: a first radio device for connecting to the wireless telecommunications network using a first radio access technology; and a second radio device for connecting to the wireless telecommunications network using a second radio access technology different from the first radio access technology, and the assistance information may be received via the first radio device. In some implementations, the assistance information may be received via the second radio device. The assistance information may include spatial information, and outputting the polling signal may include beamforming the polling signal based on the spatial information. The transmit timing of the polling signal may be based on the timing of another wireless communication system. The transmit timing of the polling signal may be determined by applying a timing advance based on the timing of the other wireless communication system, the timing advance being determined based on a value provided by the other wireless communication system.

A set of transmit beamforming weights associated with the received synchronization signal is based on a set of receive beamforming weights associated with the polling signal. The polling channel configuration may include at least one of the following: a selected polling channel format, a time-frequency resource allocation, a parameter for transmit power control, and/or a preamble sequence. The parameter for transmit power control includes at least one of the following: an initial transmit power, a power ramp amount, a parameter related to setting a configured maximum output power, and/or a number of transmissions required before transmitting using the configured maximum output power. The UE may also include means for sequentially transmitting multiple polling sequences using multiple different antenna modes, wherein a first polling sequence is separated from a second polling sequence by a guard time.

In another implementation, a non-transitory computer-readable medium stores a set of processor-executable instructions that, when executed by one or more processors of one or more devices, cause the one or more processors to: receive a polling signal from a user equipment (UE); and output multiple synchronization signals to multiple UEs from multiple transmission points in a wireless telecommunications network, wherein a first synchronization signal for a first UE from a first transmission point is associated with a first set of beamforming weights, wherein a second synchronization signal for the first UE from a second transmission point is associated with a second set of beamforming weights different from the first set of beamforming weights, wherein the first synchronization signal and the second synchronization signal for the first UE are transmitted on the same time-frequency resource, and wherein outputting the multiple synchronization signals includes: multiplexing the multiple synchronization signals associated with different simulated beamforming weights in the frequency domain, wherein the synchronization signal for the first UE associated with the first set of simulated beamforming weights is output from a specific transmission point on a first frequency subdomain, and the synchronization signal for the second UE associated with the second set of simulated beamforming weights is output from another transmission point on a second frequency subdomain, the first subdomain and the second subdomain being different.

Figures 1A-4 illustrate an overview of an example implementation of small cell detection performed by a UE. For example, as shown in Figure 1A, the UE may be in a roughly adjacent location to a set of wireless small cells and a base station. In some implementations, the base station may be, for example, an evolved Node B ("eNB") of a Long Term Evolution ("LTE") wireless telecommunications network, and the small cell may be a microcell, a femtocell, and/or other type of device via which the UE may connect to the wireless telecommunications network. The base station may thus be considered a "macrocell" relative to the small cell. The small cell may correspond to a different RAT than the base station. For example, the small cell may correspond to an HFBRAT (e.g., a RAT operating at a higher frequency band than the base station operates), and the base station may correspond to a low frequency band ("LFB") RAT (e.g., a RAT operating at a lower frequency band than the small cell operates). Therefore, the terms "HFB" and "LFB" as used herein may be used in a relative manner to indicate a higher or lower frequency band, respectively.

As shown in Figure 1A, the UE may receive assistance information from the base station (e.g., via a connection established with the base station). The assistance information may include information that assists the UE in detecting one or more small cells. For example, as will be discussed further below, the assistance information may include a cell identifier and carrier frequency of the small cell, polling channel configuration parameters (e.g., polling channel format, time-frequency resources, periodicity, parameters for transmission power control, etc.), a preamble sequence, and/or time-frequency resources for a polling response channel. The base station may send assistance information in the following circumstances: upon initial attachment to the base station, when the base station detects that the UE is near one or more small cells, when the base station receives a request for assistance information from the UE, and/or based on one or more other events.

Additionally or alternatively, as shown in Figure 1B, the UE may receive assistance information from a small cell. This may occur, for example, when the UE is currently attached to a small cell from which the assistance information is received.

As shown in FIG2 , the UE may output a polling signal to detect small cells within the range of the UE. The polling signal may be generated based on the auxiliary information (provided in FIG1A and/or 1B ). For example, as further described below, the polling signal may include a preamble sequence specified in the auxiliary information, may be transmitted in a frequency band specified in the auxiliary information, etc. Additionally or alternatively, and as described below, when outputting the polling signal, the UE may use specific time-frequency resources specified in the auxiliary information. In some implementations, the transmission timing of the polling signal output by the UE may be based on the auxiliary information.

In some implementations, the UE may output the polling signal in an omnidirectional manner. In some implementations, the UE may output the polling signal in other manners, such as a pseudo-omnidirectional manner and/or a limited directional manner. For example, in some implementations, the assistance information may specify the direction in which the UE should output the polling signal and/or may specify the location of one or more microcells (based on the location of the one or more microcells, the UE may determine the directionality of the polling signal).

Referring to FIG3 , assume that two of the three shown small cells receive a polling signal from a UE. As shown, these two small cells can provide synchronization signals to the UE. The synchronization signal from a particular small cell can be beamformed in a direction toward the UE. The small cell can determine the direction in which to beamform the synchronization signal based on the polling signal received from the UE. As shown in FIG4 , the UE can use the received synchronization signal to detect a particular small cell (e.g., to obtain timing and frequency synchronization, UE receive/transmit beam direction, cell identifier, etc.).

FIG5 illustrates an example environment 500 in which the systems and/or methods described herein may be implemented. As shown in FIG5 , the environment 500 may include a UE 505, a base station 510, a small cell 515, a small cell gateway 520, a serving gateway (“SGW”) 530, a packet data network (“PDN”) gateway (“PGW”) 535, a mobility management entity device (“MME”) 540, a policy and charging rules function (“PCRF”) 545, and a PDN 560.

The environment 500 may include an evolved packet system ("EPS") including an evolved packet core ("EPC") network operating based on the 3rd Generation Partnership Project ("3GPP") wireless communication standard and/or an LTE network. The LTE network may be part of or include a radio access network ("RAN") including one or more base stations 510, some or all of which may be in the form of eNBs, and the UE 505 may communicate with the EPC network via the eNBs. As shown, the RAN may also include one or more small cells 515, which may operate with a different RAT than the base stations 510. For example, the small cells 515 may operate with an HFB RAT, while the base stations 510 may operate with an LFB RAT. The EPC network may include one or more SGWs 530, PGWs 535, and/or MMEs 540, and may enable the UE 505 to communicate with a PDN 560 and/or an Internet Protocol ("IP") Multimedia Subsystem ("IMS") core network (not shown). The IMS core network may include a home subscriber server ("HSS"), an authentication, authorization, and accounting ("AAA") server, a call session control function ("CSCF"), and/or one or more other devices. The IMS core network may manage authentication, session initiation, account information, user profiles, etc. associated with the UE 505.

UE 505 may include a computing and communication device, such as a wireless mobile communication device capable of communicating with base station 510, small cell 515, and/or PDN 560. For example, UE 505 may include a wireless telephone; a personal communication system ("PCS") terminal (e.g., a device that combines a cellular wireless telephone with data processing and data communication functions); a personal digital assistant ("PDA") (e.g., which may include a wireless telephone, a pager, Internet/intranet access, etc.); a smartphone; a laptop computer; a tablet computer; a camera; a personal gaming system, or other types of mobile computing and communication devices. UE 505 may send traffic to and/or receive traffic from PDN 560 via base station 510, small cell 515, small cell gateway 520, SGW 530, and/or PGW 535.

The base station 510 may include one or more network devices that receive, process, and/or transmit traffic (e.g., calls, audio, video, text, and/or other data) to and/or from the UE 505. In one example, the base station 510 may be an eNB device and may be part of an LTE network. The base station 510 may receive traffic from and/or transmit traffic to the UE 505 via the SGW 530, the PGW 535, and/or the PDN 560. The base station 510 may receive traffic from and/or transmit traffic to the UE 505 via, for example, an air interface (e.g., a cellular air interface).

As described above, base station 510 may operate in an LFB RAT (e.g., a RAT corresponding to a lower frequency band than the HFB RAT associated with small cell 515). For example, base station 510 may operate in one or more frequency bands corresponding to an LTE RAT, a 3GPP third generation ("3G") RAT, a 3GPP second generation ("2G") RAT, a Code Division Multiple Access 2000 ("CDMA2000") 1X RAT, etc. Thus, base station 510 may be considered a "macro cell," while small cell 515 may be considered a "micro cell."

The small cell 515 may also include one or more network devices that receive, process, and/or transmit traffic (e.g., calls, audio, video, text, and/or other data) sent to and/or received from the UE 505. In one example, the small cell 515 may include a portable device that may be deployed (e.g., physically placed and/or installed) by an end user (e.g., an individual or business separate from the entity that owns and/or operates the base station 510). Additionally or alternatively, the small cell 515 may be deployed by the owner and/or operator of the base station 510. For example, in some implementations, a particular small cell 515 may be co-located with the base station 510. The small cell 515 may be directly communicatively coupled to the MME 540 and/or may be indirectly coupled to the SGW 530 and/or the MME 540 (e.g., via the small cell gateway 520). In some implementations, the small cell 515 (and/or the small cell gateway 520 ) may be communicatively coupled to the SGW 530 and/or the MME 540 via the PDN 560 .

The small cell 515 may generally provide enhanced connectivity to the RAN compared to that provided by the base station 510 (e.g., may provide higher data rates, wider bandwidth, and/or lower latency than the base station 510). The enhanced connectivity may be a result of the higher frequency band in which the small cell 515 operates. For example, in some implementations, at 6 gigahertz ("GHz") or higher frequency bands. In 3GPP terminology, a small cell may sometimes be referred to as a Home Node B ("HNB") or Home eNB ("HeNB").

The small cell gateway 520 may include one or more network devices via which one or more small cells 515 may be communicatively coupled to the MME 540 and/or the SGW 530. For example, the small cell gateway 520 may include one set of interfaces for communicating with the SGW 530 and/or the MME 540, and another set of interfaces (e.g., another type of interface) for communicating with one or more small cells 515. The small cell gateway 520 may aggregate control information (e.g., identifiers of the small cells 515 to which the UE 505 is connected, identifiers of the UE 505 connected to the small cells 515, handover/hand-in/hand-out instructions, etc.) from the multiple small cells 515 and may report the information to the MME 540. Additionally or alternatively, the small cell gateway 520 may aggregate user plane data (e.g., substantial traffic such as call traffic, audio/video streaming traffic, web traffic, etc.) to and/or from the multiple small cells 515. In some implementations, the small cell 515 can communicate with the MME 540 without the intervention of the small cell gateway 520 .

The SGW 530 may include one or more network devices that collect, process, search, store, and/or provide information in the manner described herein. For example, the SGW 530 may aggregate traffic received from one or more base stations 510, small cells 515, and/or small cell gateways 520, and may send the aggregated traffic to the PDN 560 via the PGW 535.

The PGW 535 may include one or more network devices that collect, process, search, store, and/or provide information in the manner described herein. The PGW 535 may aggregate traffic received from one or more SGWs 530, etc., and may send the aggregated traffic to the PDN 560. The PGW 535 may also (or alternatively) receive traffic from the PDN 560 and may send the traffic to the UE 505 via the base station 510, the small cell 515, the small cell gateway 520, and/or the SGW 530.

MME 540 may include one or more computing and communication devices that perform operations to: register UE 505 with the EPS, establish a bearer channel associated with a session for UE 505, handover UE 505 from the EPS to another network, handover UE 505 from another network to the EPS, and/or perform other operations. MME 540 may perform policing of traffic sent to and/or received from UE 505.

PCRF 545 may include one or more devices that aggregate information to and from the EPC network and/or other sources. PCRF 545 may receive information about policies and/or subscriptions from one or more sources (e.g., a subscriber database) and/or from one or more users (e.g., an administrator associated with PCRF 545).

The PDN 560 may include one or more wired and/or wireless networks. For example, the PDN 560 may include an Internet Protocol ("IP")-based PDN, a wide area network ("WAN") (e.g., the Internet), a telecommunications provider's core network, a private enterprise network, and/or one or more other networks. The UE 505 may connect to data servers, application servers, other UEs 505, and/or other servers or applications coupled to the PDN 560 via the PGW 535. The PDN 560 may be connected to one or more other networks, such as a public switched telephone network ("PSTN"), a public land mobile network ("PLMN"), and/or another network. Although "direct" connections between certain devices are shown in FIG5 , some devices may communicate with each other via the PDN 560 (and/or another network).

6 shows an example process 600 for attaching to a particular small cell 515 by a UE 505. In some implementations, the process 600 may be performed by the UE 505.

As shown, process 600 may include receiving (at 605) small cell assistance information. For example, as mentioned above with respect to Figures 1A and 1B, UE 505 may receive small cell assistance information from base station 510 (e.g., eNB). If UE 505 has been attached to a specific small cell 515, UE 505 may receive assistance information from base station 510 and/or the specific small cell 515. The assistance information may include information based on which UE 505 can detect one or more small cells 515.

For example, the assistance information may include a cell identifier and/or a carrier frequency associated with one or more small cells 515. As described below, the carrier frequency information may be used by the UE 505 when outputting a polling sequence. In some implementations, the assistance information may indicate time-frequency resources allocated to the UE 505, via which the UE 505 may receive one or more polling response channels, including synchronization signals. For example, as described in more detail below, the small cell 515 may efficiently allocate time-frequency resources to maximize the number of UEs 505 that can receive synchronization signals and that may be connected to the small cell 515. The time-frequency resources may include, for example, a time slot number, an OFDM symbol number, a starting physical resource block ("PRB") number, and the like.

As another example, the assistance information may include a UE polling channel format (e.g., as described below), periodicity, and/or parameters for transmission power. Transmission power parameters may include, for example, an initial transmission power, a power ramp-up amount, a maximum output power, an amount of transmissions before transmitting at maximum power, and the like. In some implementations, the assistance information may include a preamble sequence that the UE 505 may use when outputting a polling sequence (which may provide contention-free transmission).

The process 600 may also include determining (at 610) polling parameters based on the source of the assistance information and/or based on other factors associated with the assistance information. For example, the UE 505 may determine the polling parameters based on whether the assistance information is received via the HFB RAT (e.g., from the small cell 515) or via the LFB RAT (e.g., from the base station 510). Specifically, for example, a cyclic prefix ("CP") period ("T _CP ") of the polling signal may differ based on whether the assistance information is received via the HFB RAT or the LFB RAT. In some implementations, when the assistance information is received via the LFB RAT, the T _CP may be a longer period than when the assistance information is received via the HFB RAT. Different T _CPs may help resolve various possible timing errors associated with different RATs.

The following relates to an example timing relationship between an LFB RAT (e.g., an LTE RAT) and an HFB RAT. It is assumed that the initial transmit timing of the UE polling channel is determined by applying the LTE uplink ("UL") timing advance value to the LTE downlink ("DL") receive timing. In LTE, the fixed timing offset T _offset between the UL/DL frame timings may be set to 0 for frequency division duplex ("FDD") and to 624·Ts (=20.312 μs) for time division duplex ("TDD"). The estimated LTE DL receive frame timing at the LTE eNB relative to the transmit frame timing may be given by Equation 1:

t _DL = _TP + ε _{UE, 1} (Formula 1)

where _Tp is the propagation delay between the LTE eNB and the UE, and εUE _,1 is the DL timing estimation error at the UE.

The physical random access channel ("PRACH") transmit timing relative to the LTE eNB's transmit timing can be given by Equation 2:

t _{PRACH, tx} =t _DL -T _offset +ε _{UE, 2} (Formula 2)

Where εUE _,2 is the initial UE transmit timing error and, according to some 3GPP standards (e.g., see 3GPP Technical Specification (“TS”) 36.133 Version 12.6.0, “Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Requirements for support of radio resource management (Release 12)”), this value should be less than ±12·Ts (=0.39 μs).

The estimated PRACH receive timing relative to the LTE eNB's transmit timing is given by Equation 3:

t _{PRACH, rx} =t _{PRACH, tx} +T _P +ε _eNB =2·T _P +ε _{UE, 1} +ε _{UE, 2} +ε _eNB -T _offset (Formula 3)

where ε _eNB is the timing estimation error at the LTE eNB.

Therefore, the uplink timing advance sent to the LTE eNB can be given by Equation 4:

T _TA =t _{PRACH, rx} +T _offset =2·T _P +ε _{UE, 1} +ε _{UE, 2} +ε _eNB (Formula 4)

When the UE applies the above TA value to the reference timing _tDL - _Toffset , the physical uplink shared channel ("PUSCH") reception timing at the LTE eNB relative to the LTE eNB's transmission timing may be given by Equation 5:

t _PUSCH =t _DL −T _offset −T _TA +ε _UE,3 +T _p =−T _offset +ε _UE,3 −ε _UE,2 −ε _eNB (Formula 5) where ε _UE,3 is the PUSCH transmission timing error at the UE.

The following information relates to timing in the HFB RAT: Similar to the LTE TDD cell phase synchronization requirements (e.g., according to 3GPP TS 36.133), the relative frame start timing error of the small cell eNB relative to the LTE subframe start timing _t at the LTE eNB can be assumed to be less than or equal to ±3 μs.

The initial UE transmit timing in the HFB relative to the transmit timing at the small cell may be given by Equation 6:

_{tUE-polling,tx} = _tDL - _TTA /2- _T'offset - _t0 =(εUE _,1 - _εUE,2 - _εeNB )/2- _T'offset - _t0 (Formula 6) where _T'offset is a fixed timing offset between UL/DL frames in the high frequency band.

The estimated UE polling signal reception timing relative to the small cell's transmission timing can be given by Formula 7:

t _{UE-polling, rx} = (ε _{UE, 1} -ε _{UE, 2} -ε _eNB )/2-T′ _offset -t _o +T′ _p +ε′ _UE +ε′ _eNB (Formula 7)

where _T′p is the propagation delay from the UE to the small cell eNB, _ε′UE is the initial UE transmit timing error in the HFB, and _ε′eNB is the timing estimation error at the small cell eNB.

There is an upper limit on the uplink timing advance required to send to the small cell eNB, as shown in Formula 8:

The DL and UL timing estimation errors in LTE are assumed to have an upper limit of 1 μs, and the UL transmit timing error and UL timing estimation error in the HFB RAT are assumed to have an upper limit of 10 ns. The range of timing offsets observed at the small cell can be given by Equation 9:

For example, if t _o =3 μs and the small cell radius is 200 m, the timing offset of the received polling signal may be given such that 1.785<te _,eNB≤4.882 (μs).

The PUSCH reception timing at the small cell relative to the transmission timing at the small cell eNB can be given by Formula 10:

t′ _PUSCH =t _{UE-polling, tx} -T′ _TA +T′ _p =-(ε′ _UE +ε′ _eNB )-T′ _offset (Formula 10)

According to some implementations, Table 1 below provides example parameters for HFB small cells.

Table 1

According to some implementations, Table 2 below provides example polling channel parameters for HFB small cells.

Table 2

In some embodiments, when using LFB (e.g., LTE) timing information, the cyclic prefix period T _CP may be equal to the sum of the maximum round-trip delay, the maximum delay spread, and the total maximum allowed timing error in the LTE and high frequency bands (e.g., 4.215 μs). For a 200m cell radius, T _CP may be equal to 1.333 μs + 0.150 μs + 4.215 μs = 5.698 μs.

For a given timing offset between the LTE eNB and the HFB small cell (within ±3 μs), the relative receive timing offset between polling signals from different UEs can be within ±3.097 μs (see Equation 9). Therefore, a CP length of 5.698 μs ensures orthogonality between the polling channels of different UEs at the small cell receiver.

A guard time period T _GT,1 between polling signals from different sectors can be used, which provides a time budget for antenna sector switching (e.g., 100 ns). The guard time period T _GT,2 at the end of the concatenated polling signal can be equal to the sum of the maximum round-trip delay and the total maximum allowed timing error in the LTE and high frequency bands (e.g., 4.215 μs). In summary, for a 200 m cell radius, T _CP = 17506·T _s = 5.699 μs, T _GT,1 = 308·T _s = 100.3 ns, and T _CT,2 = 17045·T _s = 5.549 μs.

In the case where the UE is already connected to an HFB small cell, the possible timing error in the HFB RAT can be considered negligible compared to the maximum round-trip delay. In these cases, the cyclic prefix period T _CP can be equal to the sum of the maximum round-trip delay and the maximum delay spread (e.g., 150ns), and the guard time period T _GT,2 at the end of the serial polling signal can be equal to the maximum round-trip delay. In summary, for a 200m cell radius, T _CP = 4557·T _s = 1.483μs, T _GT,1 = 308·T _s = 100.3ns, and T _GT,2 = 4096·T _s = 1.333μs.

The process 600 may also include performing (at 615) omnidirectional or limited directional small cell polling using the polling parameters. For example, the UE 505 may output one or more polling signals to locate one or more small cells 515. The polling signal may be based on the above factors (e.g., by including information indicated in the assistance information), may be formed in the direction (or directions) indicated in the assistance information, may be formed in a direction (or directions) based on the location of the small cell 515, may be in a format indicated in the assistance information, may be in a format determined based on the source of the assistance information, and so on. Examples of polling signals of different formats are described in more detail below.

In some implementations, the UE 505 may output the polling signal(s) in an omnidirectional manner (e.g., a signal of equal or approximately equal strength in 360 degrees on a two-dimensional plane and/or in three-dimensional space), a pseudo-omnidirectional manner (e.g., an arc less than 360 degrees, such as an arc of 120 degrees), or a directional manner. In some implementations, the directionality of the polling signal output by the UE 505 may be determined based on information included in the assistance information.

When transmitting the polling signal, the UE 505 may use a timing advance value to synchronize the timing of the UE 505 with the timing of the small cell 515. In some implementations, the assistance information may include a timing advance value, which may be a propagation delay between the base station 510 and the UE 505 (or may be derived in whole or in part from the propagation delay). In some implementations, the propagation delay may be measured or estimated. For example, in some implementations, the timing offset (T ₁ ) at which the polling signal is received at the small cell 515 relative to the transmission timing of the base station 510 may be based on the propagation delay (T ₂ ) between the base station 510 and the UE 505 and the propagation delay (T ₃ ) between the small cell 515 and the UE 505. In some implementations, the transmission timing of the polling signal at the UE 505 may be the same as the reception timing of the polling signal from the base station 510 by the UE 505, and accordingly, T ₁ may be equal to the sum of T ₂ and T ₃ . To improve polling signal detection performance at small cell 515, base station 510 may provide an estimated _T2 value to small cell 515. One or more of these timing offsets may be calculated by base station 510 and/or some other device or entity and provided to small cell 515.

As another example, the timing advance used by the UE 505 can be based on one or more other values. For example, in some implementations, the timing advance can be based on the round-trip delay between the base station 510 and the UE 505 (e.g., can be equal to the round-trip delay, can be equal to half of the round-trip delay, etc.). In the case where the UE 505 is already connected to a particular small cell 515, the UE 505 can apply a timing advance based on the propagation delay (one-way or round-trip) between the UE 505 and the small cell 515.

In contrast to LTE PRACH transmissions, the UE polling signal may be sent to multiple candidate serving cells before any DL signal in the HFB RAT is received, so when the UE 505 sends the polling signal, the DL path loss estimate for a particular small cell may not be available. Therefore, the initial transmit power and power ramp-up amount may be configured by the network via the LTE interface as part of dedicated higher layer assistance information. The network may determine the initial transmit power and power ramp-up amount for the UE 505 based on knowledge of the network deployment (e.g., co-located or non-co-located deployment of LTE and HFB RAT), the UE transmit power state (whether power limited), and the approximate UE location that may be obtained via the LTE interface, and/or multi-user scheduling information about the polling resources. If the UE 505 does not receive a polling response from any candidate small cell after transmitting a configured number of polling signals, the UE 505 may transmit using the configured maximum transmit power.

Based on the received polling signal, the small cell 515 can determine transmit beamforming weights (and/or beamforming patterns) to optimize the transmission of synchronization signals to the UE 505. In some implementations, the small cell 515 can use receiver beamforming weights calculated during the reception of the polling signal from the UE 505. That is, in such a scenario, the synchronization signal can be optimally beamformed for each UE 505.

As another example, when transmitting a synchronization signal, the small cell 515 may select a predefined beam pattern (e.g., by coordinating with one or more other small cells 515 in the small cell cluster). In this case, the same synchronization signal can be shared by multiple UEs 505, thereby reducing the overhead associated with providing synchronization signals. Although two examples of determining transmit beamforming weights (or patterns) are described herein, in practice, these two examples may be used together, and/or another technique may be used in conjunction with one or both of these examples, depending on various operating conditions (e.g., the number of UEs 505 connected to the base station 510, the number of UEs 505 connected to one or more small cells 515, and/or whether the UE 505 is connected to a small cell 515).

The process 600 may further include receiving (at 620) a synchronization signal from one or more small cells. The synchronization signal may include one or more synchronization sequences that the UE 505 may use to acquire timing, frequency, and/or cell identifier information associated with the particular small cell 515 that sent the synchronization signal.

The process 600 may also include selecting and attaching (at 625) to a particular small cell (from which the synchronization signal is received). For example, the UE 505 may select the particular small cell 515 based on one or more factors (e.g., the signal strength of the synchronization signal from the small cell 515, the distance from the small cell 515, and/or one or more other factors). The UE 505 may perform a process of attaching to the particular small cell 515 and may subsequently communicate with the small cell 515 (e.g., sending and/or receiving data, voice traffic, etc.).

FIG7 illustrates an example polling channel format (e.g., as described above with respect to block 615). For example, as shown, the polling format may include a CP, a preamble sequence, and a guard time ("GT"). The duration of the CP may be denoted as T _CP , the duration of the preamble sequence may be denoted as T _SEQ , and the duration of the GT may be denoted as T _GT . As shown, multiple preamble sequences associated with different antenna modes (whether the same preamble sequence or different preamble sequences) may be concatenated, and a particular preamble sequence may be separated from subsequent CPs by a GT. One GT ("GT ₁ ") may be used between concatenated preamble sequences, and another GT ("GT ₂ ") may be used at the end of the concatenated preamble sequence. The duration of GT 1 ("T _{GT 1} ") may be different from the duration of GT 2 ("T _{GT 2} "). For example, in some implementations, T _{GT 1} may provide a time budget for changing antenna modes, and T _{GT 1} may be significantly shorter than T _{GT 2} . In some implementations, TGT1 and/or TGT2 may be different based on the auxiliary information source (e.g., HFB RAT or LFB RAT). In some implementations, _TGT2 may be determined for each UE and/or each cell and may be derived from the maximum round-trip delay between the UE 505 and the specific small cell 515, the delay spread of the UE 505, and/or the maximum timing estimation error value. The timing estimation error value may be based on, for example, the timing error aggregated during operation in the LFB RAT, the timing error aggregated during operation in the HFB RAT, and/or the relative timing offset between the LFB RAT and the HFB RAT.

In general, the format of the UE polling channel may be determined based on one or more of the following factors: low latency and low UE power consumption in system detection, high probability of detection at low signal-to-noise ratios ("SNR") without requiring spatial synchronization of UE transmit antennas, one-way propagation delay estimation in uplink coordinated multipoint ("CoMP") joint reception scenarios, support for high-speed UEs, and/or intra-cell or inter-cell interference between different preambles received in the same polling radio resource. In some implementations, the polling format may be determined based on one or more factors in addition to or instead of the factors listed above.

FIG8 shows an example of a cluster of small cells 515 that transmit synchronization signals to a UE 505. Each cluster may correspond to small cells 515 that are approximately co-located (e.g., within a particular geographic area) and that may be interconnected with an extremely low-latency backhaul (sometimes referred to as an "ideal backhaul," e.g., with a one-way delay of less than 2.5 microseconds). Due to the geographically separated deployment of different small cell clusters, each small cell cluster may transmit UE-specific synchronization signals with a distinct optimal beam direction. That is, for example, the direction of the beam from small cell cluster 1 may be distinguishable from the direction of the beam from small cell cluster 2. Thus, when transmitting synchronization signals, the small cells 515 of one cluster may use the same time-frequency resources as the small cells 515 of another cluster, because the UE 505 may distinguish between different small cells 515 (or small cell clusters) based on the spatial domain in which the synchronization signals are transmitted.

Additionally or alternatively, in some implementations, a unique sequence may be mapped to each small cell cluster of a specific UE-specific synchronization signal. Thus, the UE 505 may distinguish different small cells 515 (or small cell clusters) in the code domain based on the unique sequence. In some implementations, the unique sequence associated with a specific small cell 515 and/or small cell cluster may be included in the assistance information provided to the UE 505.

FIG9 illustrates an example of FDM, which can be a time-frequency resource-efficient technique for outputting synchronization signals to UE 505. As shown in FIG9, several UEs 505 (shown as "UE1" through "UE4") can receive synchronization signals from multiple transmission points ("TPs," shown as "TP1" through "TP4"). Each TP can be a TP for a specific small cell 515 (e.g., where the small cell 515 includes multiple TPs), or can correspond to a single small cell 515. In some implementations, all of the TPs shown in FIG9 can be from a small cell cluster in FIG8, such that all TPs are located within a specific geographic area and connected to each other with a very low-latency backhaul. CoMP transmission schemes such as joint transmission schemes, coordinated beamforming schemes, and the like can be used to transmit synchronization signals. For example, the synchronization signal for UE1 can be transmitted from TP1 and TP3 in a coordinated beamforming manner.

As shown in the figure, time-frequency resources can be utilized in a UE-specific manner. For example, UE1 can receive synchronization signals on the first subband of a frequency band ("subband 1"), UE2 can receive synchronization signals on the second subband ("subband 2"), and so on. It is expected that the spatial and multi-user diversity order within a small cell cluster is smaller than the spatial and multi-user diversity order between different small cell clusters. Therefore, orthogonal time-frequency resource allocation between different UEs may be beneficial for reliable detection of synchronization signals.

In analog-digital hybrid beamforming, analog beamforming weights can be applied to the entire frequency band. Therefore, if multiple synchronization signals are transmitted from a set of antennas at a specific TP, the FDM of multiple UE-specific synchronization signals within one OFDM symbol is limited. In this case, only synchronization signals with the same analog beamforming weights can be frequency multiplexed on the same OFDM symbol.

In order to allow flexible FDM of multiple UE-specific synchronization signals, multiple TPs within a small cell cluster can be coordinated so that multiple UE-specific synchronization signals scheduled on the same OFDM symbol but associated with different optimal analog beamforming weights are sent from different TPs or different antenna groups of the same TP. For example, TP1 is used to transmit to UE1 and TP2 is used to transmit to UE2, and the synchronization signals of UE1 and UE2 associated with different analog beamforming weights are frequency multiplexed in one OFDM symbol. The FDM of UE2 and UE4 is accomplished using two groups of antennas via TP2, one for UE2 and the other for UE4. In some implementations, the UE 505 can be signaled in advance (e.g., in assistance information) which subband is associated with a specific UE 505. In this way, synchronization signals can be sent to multiple UEs 505 with different transmit analog beamforming weights within one OFDM symbol via multiple TPs.

FIG10 is a diagram of example components of a device 1000. Some of the devices shown in FIG1 and/or 2 may include one or more devices 1000. Device 1000 may include a bus 1010, a processor 1020, a memory 1030, an input component 1040, an output component 1050, and a communication interface 1060. In another implementation, device 1000 may include more, fewer, or differently arranged components.

The bus 1010 may include one or more communication paths that allow communication between components of the device 1000. The processor 1020 may include processing circuitry such as a processor, a microprocessor, or processing logic that can interpret or execute instructions. The memory 1030 may include any type of dynamic storage device that can store information and instructions for execution by the processor 1020 and/or any type of non-volatile storage device that can store information for use by the processor 1020.

Input components 1040 may include mechanisms that allow an operator to input information to device 1000, such as a keyboard, keypad, buttons, switches, etc. Output components 1050 may include mechanisms that output information to the operator, such as a display, a speaker, one or more light emitting diodes ("LEDs"), etc.

The communication interface 1060 may include any transceiver-like mechanism that enables the device 1000 to communicate with other devices and/or systems. For example, the communication interface 1060 may include an Ethernet interface, an optical interface, a coaxial interface, etc. The communication interface 1060 may include a wireless communication device, such as an infrared (IR) receiver, a radio device, a WiFi radio device, a cellular radio device, etc. The wireless communication device may be coupled to an external device, such as a remote control, a wireless keyboard, a mobile phone, etc. In some embodiments, the device 1000 may include more than one communication interface 1060. For example, the device 1000 may include an optical interface and an Ethernet interface.

Device 1000 can perform some of the operations described above. Device 1000 can perform these operations in response to processor 1020 executing software instructions stored in a computer-readable medium (e.g., memory 1030). Computer-readable media can be defined as non-transitory memory devices. The memory device may include space within a single physical memory device or space distributed across multiple physical memory devices. Software instructions can be read into memory 1030 from another computer-readable medium or from another device. The software instructions stored in memory 1030 can cause processor 1020 to perform the processing described herein. Alternatively, hard-wired circuits can be used instead of or in combination with software instructions to implement the processing described herein. Therefore, the implementation described herein is not limited to any particular combination of hardware circuits and software.

In the foregoing description, various embodiments have been described with reference to the accompanying drawings. However, it will be apparent that various modifications and changes may be made thereto, and that additional embodiments may be realized, without departing from the broader scope of the invention as set forth in the appended claims. The description and drawings are therefore to be regarded in an illustrative rather than a restrictive sense.

For example, although a sequence of blocks is described with respect to Figure 6, the order of the blocks may be modified in other implementations. In addition, blocks that are not dependent on each other may be executed in parallel.

It is apparent that, in the implementations shown in the figures, the example aspects described above can be implemented in many different software, firmware, and hardware forms. The actual software code or specific control hardware used to implement these aspects should not be construed as limiting. Therefore, the operation and behavior of these aspects are described without reference to specific software code - it should be understood that software and control hardware can be designed to implement these aspects based on the description herein.

Furthermore, some portions of the present invention may be implemented as “logic” that performs one or more functions. This logic may include hardware (e.g., an application specific integrated circuit (“ASIC”) or a field programmable gate array (“FPGA”)) or a combination of hardware and software.

Even if the claims recite and/or the specification disclose specific combinations of features, these combinations are not intended to limit the invention. In fact, many of these features can be combined in ways not explicitly recited in the claims and/or disclosed in the specification.

The elements, actions or instructions used in this application should not be interpreted as being critical or indispensable unless explicitly stated as such. As used herein, the use instance of the term "and" does not necessarily exclude the interpretation of the phrase "and/or" being included in the example. Similarly, as used herein, the use instance of the term "or" does not necessarily exclude the interpretation of the phrase "and/or" being included in the example. Also, as used herein, the article "one" is intended to include one or more items and can be used interchangeably with the phrase "one or more". If only one item is intended to be represented, the term "one", "single", "only" or similar language is used. In addition, the phrase "based on" is intended to represent "based at least in part on", unless explicitly stated otherwise.

Claims (48)

1. A user equipment "UE", comprising: Radio components for connecting to wireless telecommunications networks; Memory devices for storing processor-executable instruction sets; and Processing circuitry for executing the processor-executable instruction set, wherein executing the processor-executable instruction set causes the UE to: Receive auxiliary information, the auxiliary information including at least one of the following: The carrier frequency and one or more cell identifiers associated with the wireless telecommunications network, or Polling channel configuration; A polling signal is generated based on the auxiliary information; The generated polling signal is output via the radio component; In response to the polling signal, a synchronization signal is received, the synchronization signal being received via the radio component from one or more cells in the wireless telecommunications network; and The received synchronization signal is used to detect a specific cell among the one or more cells in the wireless telecommunications network. 2. The UE of claim 1, wherein the auxiliary information includes a carrier frequency associated with the wireless telecommunications network. The output of the polling signal includes outputting the polling signal based on the carrier frequency. 3. The UE according to claim 1, wherein the auxiliary information includes the polling channel configuration. The output of the polling signal includes outputting the polling signal according to the polling channel configuration. 4. The UE according to claim 1, wherein the auxiliary information further includes an indication of time-frequency resource allocation for the synchronization signal. 5. The UE according to claim 1, wherein executing the processor-executable instruction set causes the UE to: Based on the radio access technology through which the auxiliary information is received, one or more parameters associated with the polling signal are determined. 6. The UE of claim 5, wherein the one or more parameters determined based on the radio access technology via which the auxiliary information is received include at least one of the following: During the protection period associated with the polling signal, or The cyclic prefix period associated with the polling signal. 7. The UE of claim 1, wherein the radio component is a first radio component associated with a first radio access technology. The UE further includes a second radio component associated with a second radio access technology different from the first radio access technology. The auxiliary information is received via the first radio component. 8. The UE of claim 1, wherein the radio component is a first radio component associated with a first radio access technology. The UE further includes a second radio component associated with a second radio access technology different from the first radio access technology. The auxiliary information is received via the second radio component. 9. The UE according to claim 1, wherein outputting the polling signal includes: outputting the polling signal in an omnidirectional, pseudo-omnidirectional, or directional mode. 10. The UE according to claim 1, wherein the wireless telecommunications network comprises: One or more base stations operate in frequency bands associated with the Long Term Evolution (LTE) standard, and One or more small cells operate on a frequency band higher than the frequency band associated with the Long Term Evolution (LTE) standard. The one or more base stations mentioned herein are synchronized with the one or more small cells. 11. The UE of claim 1, wherein the auxiliary information includes spatial information, and outputting the polling signal includes beamforming the polling signal based on the spatial information. 12. The UE according to claim 1, wherein the timing of transmitting the polling signal is based on the timing of another wireless communication system. 13. The UE of claim 12, wherein the transmission timing of the polling signal is determined by applying a timing advance based on the timing of the other wireless communication system, the timing advance being determined based on a value provided by the other wireless communication system. 14. The UE of claim 1, wherein a set of transmit beamforming weights associated with the received synchronization signal is based on a set of receive beamforming weights associated with the polling signal. 15. The UE of claim 1, wherein the polling channel configuration includes at least one of the following: Selected polling channel format, Time-frequency resource allocation Parameters used for transmission power control, or Preamble sequence. 16. The UE of claim 15, wherein the parameters for transmission power control include at least one of the following: Initial transmission power, Power ramp-up, Parameters related to setting the configured maximum output power, or The number of polling signal transmissions required before transmitting using the configured maximum output power. 17. The UE of claim 1, wherein executing the processor-executable instructions further causes the UE to: Multiple polling sequences are transmitted sequentially using multiple different antenna patterns, with the first polling sequence being separated from the second polling sequence by a guard time. 18. A cell device in a wireless telecommunications network, the cell device comprising: Radio components for communicating with user equipment (“UE”); Memory devices for storing processor-executable instruction sets; and Processing circuitry for executing the processor-executable instruction set, wherein executing the processor-executable instruction set causes the cell device to: The auxiliary information is output to the UE, and the auxiliary information includes at least one of the following: The carrier frequency associated with the wireless telecommunications network, Polling channel configuration, or Polling response channel configuration; Receive a polling signal generated by the UE based on the auxiliary information from the UE; Generating a synchronization signal for the UE, the generation including: One or more beamforming weights are determined based on the received polling signals; and In response to the polling signal, a generated synchronization signal is output to the UE via a polling response channel, the polling response channel corresponding to the polling response channel configuration. 19. The cell device of claim 18, wherein the cell device operates on a frequency band higher than the frequency band in which the Long Term Evolution (“LTE”) base station network operates. 20. The cell device of claim 19, wherein the cell device is synchronized with one or more LTE base stations. 21. The cell equipment of claim 18, wherein the auxiliary information includes a carrier frequency associated with the wireless telecommunications network. The polling signal is received on a carrier frequency associated with the wireless telecommunications network. 22. The cell device of claim 18, wherein executing the processor-executable instructions further causes the cell device to: One or more transmission points that output the synchronization signal via the polling response channel are determined, the determination being based on at least one of the following: The signal strength of the received polling signal, The signal power of the received polling signal transmitted by the UE. The timing offset of the received polling signal, or The load status of the wireless telecommunications network. 23. The cell device of claim 18, wherein the auxiliary information further includes the cell identifier of the cell device. 24. The cell device of claim 18, wherein the one or more beamforming weights are determined based on at least one of the following: Beamforming weights associated with the received polling signal, or A set of beamforming weights. 25. A computer-readable medium storing a computer program, the computer program being executable by a processor to implement the steps of a method performed by a user equipment (UE), the UE including radio components for connecting to a wireless telecommunications network, the steps comprising: Receive auxiliary information, the auxiliary information including at least one of the following: The carrier frequency and one or more cell identifiers associated with the wireless telecommunications network, or Polling channel configuration; A polling signal is generated based on the auxiliary information; The generated polling signal is output via the radio component; In response to the polling signal, a synchronization signal is received, the synchronization signal being received via the radio component from one or more cells in the wireless telecommunications network; and The received synchronization signal is used to detect a specific cell among the one or more cells in the wireless telecommunications network. 26. The computer-readable medium of claim 25, wherein the auxiliary information includes a carrier frequency associated with the wireless telecommunications network. The output of the polling signal includes outputting the polling signal based on the carrier frequency. 27. The computer-readable medium of claim 25, wherein the auxiliary information includes the polling channel configuration. The output of the polling signal includes outputting the polling signal according to the polling channel configuration. 28. The computer-readable medium of claim 25, wherein the auxiliary information further includes an indication of time-frequency resource allocation for the synchronization signal. 29. The computer-readable medium of claim 25, wherein the method further comprises: Based on the radio access technology through which the auxiliary information is received, one or more parameters associated with the polling signal are determined. 30. The computer-readable medium of claim 29, wherein the one or more parameters determined based on the radio access technology via which the auxiliary information is received include at least one of the following: During the protection period associated with the polling signal, or The cyclic prefix period associated with the polling signal. 31. The computer-readable medium of claim 25, wherein the radio component is a first radio component associated with a first radio access technology. The UE further includes a second radio component associated with a second radio access technology different from the first radio access technology. The auxiliary information is received via the first radio component. 32. The computer-readable medium of claim 25, wherein the radio component is a first radio component associated with a first radio access technology. The UE further includes a second radio component associated with a second radio access technology different from the first radio access technology. The auxiliary information is received via the second radio component. 33. The computer-readable medium of claim 25, wherein outputting the polling signal comprises: outputting the polling signal in an omnidirectional, pseudo-omnidirectional, or directional mode. 34. The computer-readable medium of claim 25, wherein the wireless telecommunications network comprises: One or more base stations operate in frequency bands associated with the Long Term Evolution (LTE) standard, and One or more small cells operate on a frequency band higher than the frequency band associated with the Long Term Evolution (LTE) standard. The one or more base stations mentioned herein are synchronized with the one or more small cells. 35. The computer-readable medium of claim 25, wherein the auxiliary information includes spatial information, and outputting the polling signal includes beamforming the polling signal based on the spatial information. 36. The computer-readable medium of claim 25, wherein the timing of transmitting the polling signal is based on the timing of another wireless communication system. 37. The computer-readable medium of claim 36, wherein the transmission timing of the polling signal is determined by applying a timing advance based on the timing of the other wireless communication system, the timing advance being determined based on a value provided by the other wireless communication system. 38. The computer-readable medium of claim 25, wherein a set of transmit beamforming weights associated with the received synchronization signal is based on a set of receive beamforming weights associated with the polling signal. 39. The computer-readable medium of claim 25, wherein the polling channel configuration comprises at least one of the following: Selected polling channel format, Time-frequency resource allocation Parameters used for transmission power control, or Preamble sequence. 40. The computer-readable medium of claim 39, wherein the parameters for transmission power control include at least one of the following: Initial transmission power, Power ramp-up, Parameters related to setting the configured maximum output power, or The number of polling signal transmissions required before transmitting using the configured maximum output power. 41. The computer-readable medium of claim 25, wherein the method further comprises: Multiple polling sequences are transmitted sequentially using multiple different antenna patterns, with the first polling sequence being separated from the second polling sequence by a guard time. 42. A computer-readable medium storing a computer program that can be executed by a processor to implement the steps of a method performed by a cell device in a wireless telecommunications network, the cell device including radio components for communicating with a user equipment (UE), the steps comprising: The auxiliary information is output to the UE, and the auxiliary information includes at least one of the following: The carrier frequency associated with the wireless telecommunications network, Polling channel configuration, or Polling response channel configuration; Receive a polling signal generated by the UE based on the auxiliary information from the UE; Generating a synchronization signal for the UE, the generation including: One or more beamforming weights are determined based on the received polling signals; and In response to the polling signal, a generated synchronization signal is output to the UE via a polling response channel, the polling response channel corresponding to the polling response channel configuration. 43. The computer-readable medium of claim 42, wherein the cell device operates in a frequency band higher than the frequency band in which the Long Term Evolution (“LTE”) base station network operates. 44. The computer-readable medium of claim 43, wherein the cell device is synchronized with one or more LTE base stations. 45. The computer-readable medium of claim 42, wherein the auxiliary information includes a carrier frequency associated with the wireless telecommunications network. The polling signal is received on a carrier frequency associated with the wireless telecommunications network. 46. The computer-readable medium of claim 42, wherein the method further comprises: One or more transmission points that output the synchronization signal via the polling response channel are determined, the determination being based on at least one of the following: The signal strength of the received polling signal, The signal power of the received polling signal transmitted by the UE. The timing offset of the received polling signal, or The load status of the wireless telecommunications network. 47. The computer-readable medium of claim 42, wherein the auxiliary information further includes the cell identifier of the cell device. 48. The computer-readable medium of claim 42, wherein the one or more beamforming weights are determined based on at least one of the following: Beamforming weights associated with the received polling signal, or A set of beamforming weights.