HK1175630A - Ferforming measurements in wireless communications using multiple carriers - Google Patents

Description

Performing measurements with multiple carriers in wireless communications

Cross Reference to Related Applications

The present application claims the benefit of the following applications: U.S. provisional application No.61/289,887 entitled "METHOD AND APPARATUS FOR measuring purposes USING MULTIPLE CARRIERS" filed on 23.12.2009, U.S. provisional application No.61/329,629 entitled "METHOD AND APPARATUS FOR measuring purposes USING MULTIPLE CARRIERS" filed on 30.4.2010, AND U.S. provisional application No.61/329,629 entitled "METHOD AND APPARATUS FOR measuring purposes USING MULTIPLE CARRIERS", filed on 1.10.2010, AND U.S. provisional application No.61/388,876 entitled "METHOD AND APPARATUS FOR measuring purposes IN WIRELESS USING MULTIPLE uses USING MULTIPLE CARRIERS", filed on 1.10.2010, the entire contents of each of which are hereby incorporated by reference IN their entirety FOR all purposes.

Background

A wireless transmit/receive unit (WTRU) may perform intra-frequency/inter-frequency and inter-radio access technology (inter-RAT) measurements for mobility purposes. Intra-frequency measurements may be performed by the WTRU on the same carrier frequency as its current serving cell. The WTRU may make such measurements without measurement gaps. Inter-frequency neighbor or cell measurements may be performed by the WTRU on a different carrier frequency than the current serving cell. The WTRU may not be able to perform such measurements without measurement gaps. The measurement gap may be a period during which the WTRU is unable to perform or receive any transmissions on the frequency of the serving cell. The inter-RAT measurements may be performed by the WTRU on a carrier frequency used by another RAT, which may not be the carrier frequency used by the WTRU at the current serving cell.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the specification. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not intended as a limitation on any or all of the disadvantages identified in any part of this disclosure.

Methods, systems, and apparatus for reducing signaling overhead generated by measurement configurations utilizing multiple carriers in wireless communications may be used. The method may be based on the transmission of one or more measurement reports triggered by various events.

Embodiments contemplate that a wireless transmit/receive unit (WTRU) may include a processor. The processor may be configured, at least in part, to determine a Radio Resource Control (RRC) connection state and reconfigure a measurement configuration. The reconfiguration of the measurement configuration may include removing at least one parameter from the measurement configuration. The RRC connection state may be determined as at least one of an RRC connection reestablishment or an RRC connection reconfiguration. Embodiments contemplate that the processor may be further configured to remove the parameter from the measurement configuration during at least one of an RRC connection reestablishment or an RRC connection reconfiguration. And the processor may be further configured to remove at least one parameter from the measurement configuration based on at least one condition.

Embodiments contemplate that a wireless transmit/receive unit (WTRU) may include a processor. The processor may be configured, at least in part, to configure a measurement report based on at least one condition, and the measurement report may include measurements on one or more frequencies on which the WTRU may be configured to operate. The processor may be further configured to transmit the measurement report. The measurement report may include measurements on one or more frequencies on which the WTRU may be configured to operate other than the first frequency. The first frequency may be associated with at least one condition. Embodiments contemplate that the at least one condition may include a signal quality of a carrier associated with a first frequency becoming below a first threshold and a signal quality of a carrier associated with one or more frequencies on which the WTRU may be configured to operate other than the first frequency being above a second threshold.

Embodiments contemplate that a wireless transmit/receive unit (WTRU) may include a processor. The processor may be configured, at least in part, to determine at least one condition that may be associated with one or more carriers. The WTRU may be configured to operate on at least one of the one or more carriers. And, the processor may be configured to transmit a measurement report according to the at least one condition. Embodiments contemplate that the at least one condition may include a quality measure associated with at least one of the one or more carriers becoming below a threshold. The quality measurement may be at least one of a signal strength or a signal quality, and the WTRU may be configured to operate on at least one of the one or more carriers on one or more frequencies.

Drawings

The invention may be understood in more detail from the following description, given by way of example, with reference to the accompanying drawings, in which:

FIG. 1A is a system diagram of an example communication system in which one or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit (WTRU) that may be used in the communication system shown in FIG. 1A;

fig. 1C is a system diagram of an example radio access network and an example core network that may be used in the communication system shown in fig. 1A;

FIG. 2 is a graph showing signal quality;

FIG. 3 is a block diagram of an exemplary on-demand (on-demand) measurement report;

FIG. 4 is a block diagram of an exemplary measurement embodiment;

FIG. 5 is a block diagram of an exemplary measurement embodiment;

FIG. 5A is a block diagram of an exemplary measurement embodiment; and

fig. 6 is a block diagram of an exemplary measurement embodiment.

Detailed Description

Fig. 1A is a system diagram of an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to a plurality of wireless users. The communication system 100 may enable multiple wireless users to access the content by sharing system resources, including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), and the like.

As shown in fig. 1A, the communication system 100 may include wireless transmit/receive units (WTRUs) 102a,102b,102c,102 d; a Radio Access Network (RAN) 104; a core network 106; a Public Switched Telephone Network (PSTN) 108; the internet 110; and other networks 112, it is to be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a,102b,102c,102d may be any type of device configured to operate and/or communicate in a wireless environment. For example, the WTRUs 102a,102b,102c,102d may be configured to transmit and/or receive wireless signals and may include User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a Personal Digital Assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, consumer electronics, and the like.

Communication system 100 may also include base station 114a and base station 114 b. Each of the base stations 114a and 114b may be any type of device configured to wirelessly interact with at least one of the WTRUs 102a,102b,102c,102d to facilitate access to one or more communication networks, such as the core network 106, the internet 110, and/or the network 112. The base stations 114a, 114B may be, for example, Base Transceiver Stations (BTSs), node B, e node bs, home enodeb, site controllers, Access Points (APs), wireless routers, and so forth. Although the base stations 114a, 114b are each described as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

The base station 114a may be part of the RAN 104, and the RAN 104 may also include other base stations and/or network elements (not shown), such as Base Station Controllers (BSCs), Radio Network Controllers (RNCs), relay nodes, and so forth. Base station 114a and/or base station 114b may be configured to transmit and/or receive wireless signals within a particular geographic area, which may be referred to as a cell (not shown). The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each cell sector. In another embodiment, the base station 114a may use multiple-input multiple-output (MIMO) technology, whereby the base station 114a may use multiple transceivers for each sector of a cell.

The base stations 114a, 114b may communicate with one or more of the WTRUs 102a,102b,102c,102d over the air interface 116. The air interface 116 may be any suitable wireless communication link (e.g., Radio Frequency (RF), microwave, Infrared (IR), Ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable Radio Access Technology (RAT).

More specifically, as described above, communication system 100 may be a multiple access system and may use one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 and the WTRUs 102a,102b,102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) terrestrial radio access (UTRA), which may utilize wideband cdma (wcdma) to establish the air interface 116. WCDMA may include communication protocols such as High Speed Packet Access (HSPA) and/or evolved HSPA (HSPA +). HSPA may include High Speed Downlink Packet Access (HSDPA) and/or High Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114a and the WTRUs 102a,102b,102c may implement a radio technology such as evolved UMTS terrestrial radio access (E-UTRA) that may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-advanced (LTE-a).

In another embodiment, the base station 114a and the WTRUs 102a,102b,102c may implement a radio technology such as IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA20001X, CDMA2000EV-DO, temporary Standard 2000 (IS-2000), temporary Standard 95 (IS-95), temporary Standard 856 (IS-856), Global System for Mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE (GERAN), and the like.

The base station 114B in fig. 1A may be, for example, a wireless router, a home nodeb, a home enodeb, or an access point, and may use any suitable RAT to facilitate wireless connectivity in a local area (e.g., a place of business, a residence, a vehicle, a campus, etc.). In one embodiment, the base station 114b and the WTRUs 102c,102d may implement a radio technology such as IEEE 802.11 to establish a Wireless Local Area Network (WLAN). In another embodiment, the base station 114b and the WTRUs 102c,102d may implement a radio technology such as IEEE 802.15 to establish a Wireless Personal Area Network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c,102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE-a, etc.) to establish the pico cell or the femto cell. As shown in fig. 1A, the base station 114b may have a direct connection to the internet 110. Thus, the base station 114b need not have access to the internet 110 via the core network 106.

The RAN 104 may communicate with a core network 106, which core network 106 may be any type of network configured to provide voice, data, application, and/or voice over network protocol (VoIP) services to one or more of the WTRUs 102a,102b,102c,102 d. For example, the core network 106 may provide call control, billing services, mobile location-based services, prepaid calling, internet connectivity, video distribution, etc., and/or perform high-level security functions (e.g., user authentication). Although not shown in fig. 1A, it is to be appreciated that the RAN 104 and/or the core network 106 may communicate directly or indirectly with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to connecting to the RAN 104, which may use E-UTRA radio technology, the core network 106 may also communicate with other RANs (not shown) that use GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102a,102b,102c,102d to access the PSTN108, the internet 110, and/or other networks 112. The PSTN108 may include a circuit-switched telephone network that provides Plain Old Telephone Service (POTS). The internet 110 may include a system of globally interconnected computer network devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP) in the TCP/IP internet protocol suite. The network 112 may include wired or wireless communication networks owned and/or operated by other service providers. For example, the network 112 may include another core network connected with one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102a,102b,102c,102d in the communication system 100 may include multi-mode capabilities, i.e., the WTRUs 102a,102b,102c,102d may include multiple transceivers that communicate with different wireless networks over different wireless links. For example, the WTRU102c as shown in figure 1A may be configured to communicate with a base station 114a, which may use a cellular-based radio technology, and with a base station 114b, which may use an IEEE 802 radio technology.

Figure 1B is a system diagram of an example WTRU 102. As shown in fig. 1B, the WTRU102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a Global Positioning System (GPS) chipset 136, and other peripherals 138. It is to be appreciated that the WTRU102 may include any subcombination of the above elements while remaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of Integrated Circuit (IC), a state machine, or the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functions that enable the WTRU102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120, and the transceiver 120 may be coupled to a transmit/receive element 122. Although fig. 1B depicts processor 118 and transceiver 120 as a single component, it is to be understood that processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

Transmit/receive element 122 may be configured to transmit signals to and receive signals from a base station (e.g., base station 114 a) over air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In another embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and receive both RF and optical signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

Furthermore, although transmit/receive element 122 is depicted in fig. 1B as a single element, WTRU102 may include any number of transmit/receive elements 122. More specifically, the WTRU102 may use MIMO technology. Thus, in one embodiment, to transmit and receive wireless signals over the air interface 116, the WTRU102 may include two or more transmit/receive elements 122 (e.g., multiple antennas).

Transceiver 120 may be configured to modulate signals to be transmitted by transmit/receive element 122 and to demodulate signals received by transmit/receive element 122. As described above, the WTRU102 may have multi-mode capabilities. As such, the transceiver 120 may include multiple transceivers such that the WTRU102 may communicate via multiple RATs (e.g., UTRA and IEEE 802.11).

The processor 118 of the WTRU102 may be coupled to and may receive user input data from a speaker/microphone 124, a keyboard 126, and/or a display/touch pad 128, such as a Liquid Crystal Display (LCD) display unit or an Organic Light Emitting Diode (OLED) display unit. The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. Further, the processor 118 may access information from, and store data in, any suitable type of memory, such as the non-removable memory 106 and/or the removable memory 132. The non-removable memory 106 may include Random Access Memory (RAM), Read Only Memory (ROM), a hard disk, or any other type of storage memory device. The removable memory 132 may include a Subscriber Identity Module (SIM) card, a memory stick, a Secure Digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory physically located off the WTRU102, such as on a server or home computer (not shown).

The processor 118 may receive power from the power source 134 and may be configured to distribute and/or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to a GPS chipset 136. The GPS chipset 136 may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU102 may receive location information from base stations (e.g., base stations 114a, 114 b) over the air interface 116 and/or determine the location of the WTRU102 based on the timing (timing) of signals received from two or more neighboring base stations. It is to be appreciated that the WTRU102 may acquire location information by any suitable location determination method while remaining consistent with an embodiment.

The processor 118 may also be coupled with other peripherals 138, which peripherals 138 may include one or more software and/or hardware modules that provide additional features, functionality, and/or wired or wireless connectivity. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos or video), Universal Serial Bus (USB) ports, vibration devices, television receiversTransmitter, hand-free earphone and BluetoothA module, a Frequency Modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, etc.

Fig. 1C is a system diagram of RAN 104 and core network 106 according to one embodiment. As described above, the RAN 104 may use E-UTRA radio technology to communicate with the WTRUs 102a,102b, and 102c over the air interface 116. The RAN 104 may also communicate with a core network 106.

The RAN 104 may include enodebs 140a, 140B, 140c, but it is understood that the RAN 104 may include any number of enodebs while remaining consistent with an embodiment. each of the enode bs 140a, 140B, 140c may include one or more transceivers for communicating with the WTRUs 102a,102B,102c over the air interface 116. In one embodiment, the enode bs 140a, 140B, 140c may implement MIMO technology. Thus, for example, the enodeb 140a may use multiple antennas to transmit wireless signals to the WTRU102a and to receive wireless signals from the WTRU102 a.

each of the enodebs 140a, 140B, 140c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink and/or downlink, and the like. As shown in FIG. 1C, eNode Bs 140a, 140B, 140C may communicate with each other over an X2 interface.

The core network 106 shown in fig. 1C may include a mobility management gateway (MME) 142, a serving gateway 144, and a Packet Data Network (PDN) gateway 146. While each of the above elements are described as part of the core network 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the core network operator.

MME 142 may be connected with each of enodebs 142a, 142B, 142c in RAN 104 via an S1 interface and may act as a control node. For example, the MME 142 may be responsible for authenticating users of the WTRUs 102a,102b,102c, bearer activation/deactivation, selecting a particular serving gateway during initial attachment of the WTRUs 102a,102b,102c, and the like. MME 142 may also provide control plane functionality for exchanges between RAN 104 and other RANs (not shown) that use other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may connect with each of the enodebs 140a, 140B, 140c in the RAN 104 via an S1 interface. The serving gateway 144 may generally route and forward user data packets to/from the WTRUs 102a,102b,102 c. The serving gateway 144 may also perform other functions such as anchoring the user plane during inter-enodeb handovers, triggering paging when downlink data is available for the WTRUs 102a,102B,102c, managing and storing the context of the WTRUs 102a,102B,102c, and the like.

The serving gateway 144 may also be connected to a PDN gateway 146, which PDN gateway 146 may provide the WTRUs 102a,102b,102c with access to a packet-switched network (e.g., the internet 110), thereby facilitating communication between the WTRUs 102a,102b,102c and IP-enabled devices.

The core network 106 may facilitate communication with other networks. For example, the core network 106 may provide the WTRUs 102a,102b,102c with access to a circuit-switched network (e.g., the PSTN 108), thereby facilitating communication between the WTRUs 102a,102b,102c and conventional landline communication devices. For example, the core network 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that interfaces between the core network 106 and the PSTN 108. In addition, the core network 106 may provide the WTRUs 102a,102b,102c with access to the network 112, which network 112 may include other wired or wireless networks owned and/or operated by other service providers.

The network may provide the WTRU with the measurement configuration through dedicated Radio Resource Control (RRC) signaling. For example, in an LTE system, the measurement configuration may include measurement targets corresponding to intra/inter single frequency measurements; a report configuration corresponding to a list of report specifications and associated report formats; a measurement identifier corresponding to an identifier list linking one measurement target with one report configuration; a quantity configuration corresponding to the quantity of measurements (which may be a threshold, for example) and/or associated filtering for request events and reporting of one measurement type or possibly more than one measurement type; and a measurement gap or gap configuration or arrangement.

In an evolved Universal Mobile Telecommunications System (UMTS) terrestrial radio access network (E-UTRAN), for example, a single measurement target may be configured on a per carrier frequency basis. Conceptually, targets may be stored in tables (tables), for example, and different operations may be defined to add, remove, and modify tables.

For example, at least one measurement identity may be associated with a single pair (pair) (e.g., configured with at least one measurement target for one report). In this example, the event reporting configuration may include a combination of one event, one hysteresis parameter, and the trigger time of the trigger-type event. The WTRU may be configured with multiple instances of the same event. This may provide flexibility to reuse the same reporting configuration, e.g. having the same trigger for different measurement targets, e.g. for different frequencies, linked using different measurement identities. This implies that different measurement identities may be used to link the same measurement target (e.g. frequency) with different reporting configurations (e.g. multiple triggers).

Problems arise when attempting to apply existing measurement schemes to WTRUs that use carrier aggregation. One problem may be that the network may configure more than one measurement target (one per frequency) for the purpose of deconfiguration management of component carriers, each measurement target comprising one reporting configuration and one measurement identity.

Using similar or identical reporting configurations with different measurement targets (e.g., for different frequencies) may result in near (near) synchronous multiple transmissions of measurement reports. Methods are envisaged that minimize the overhead in signalling due to measurement configuration when operating with multiple carriers, for example where such methods would result in fewer measurement reports.

For WTRUs operating with a single carrier or multiple carriers, embodiments contemplate that the signal quality and/or level received from a carrier may be degraded, or perhaps rapidly degraded. This may result from different reasons, such as when the WTRU may be about to leave the coverage area of this carrier, or be gradually close to an interfering (interfering) home cell or femto cell on the same frequency. Loss of connection to the network can occur if the carrier in question has a special role in the connection to the network, for example, if it corresponds to a special cell or primary (primary) serving cell in existing methods. To prevent this, the network reconfigures the WTRU so that the signal quality from the carrier corresponding to the primary serving cell is appropriate. Such reconfiguration requires that the network obtain information about the quality of other carriers early enough after the WTRU may measure the loss of carrier quality and/or the WTRU may notice the loss of carrier quality corresponding to the primary serving cell.

Upon detecting that the signal quality and/or signal strength of the primary serving cell is about to fall below a threshold, the WTRU may report measurements pertaining to cells on the same frequency as this cell. In this way, the network may not immediately get information of other cells at other frequencies unless it is possible that another event is independently triggered at the same time or that periodic reports for one of the other frequencies are transmitted at about the same time. Even if reconfiguration may be employed to avoid this situation, the delay may cause the WTRU to lose connection with the network.

The configuration of multiple Component Carrier (CC) cells included in the handover command may cause a similar problem to occur. The network may not have the latest measurement results for other carriers on the target base station unless the measurement results may trigger a measurement event report.

Embodiments contemplate that the network may determine when to configure the addition/removal of serving cells to/from a multi-carrier operable WTRU on demand. At least one factor in such a determination may be measurements made from these carriers, particularly where the coverage area differs between different available carrier frequencies. In such a case, it is possible that the measurement results are available at the appropriate time.

For example, if at least one of the configured carriers falls below one or more thresholds, there is no measurement event reporting a quality degradation of one of the configured carriers. One view of this problem can be seen in fig. 2. As illustrated in the example of fig. 2, the WTRU may not require a high data rate, so when the signal quality of the adjacent Component Carrier (CC) becomes higher (or rises higher) than a threshold, the WTRU may continue with single carrier operation. Also, when the WTRU later requires a higher data rate, the network may not know whether the signal quality of the neighboring Component Carrier (CC) is still good enough to be reconfigured, at least because there is no measurement event reporting that the neighboring Component Carrier (CC) becomes below (or falls below) the threshold.

The conventional procedure of handling measurement identity in inter-frequency handover or re-establishment procedures cannot be directly applied in case the WTRU is multi-carrier operated in source or target configuration. For example, one problem may be that exchanging measurement objects (MeasObjects) for each measurement identity (MeasId) corresponding to one or more events may result in meaningless configuration on certain carriers. This may occur, for example, when the frequency corresponding to the Primary Component Carrier (PCC) in the source configuration may not be the configured CC in the target configuration, while the frequency corresponding to the PCC in the target configuration may be the configured CC (i.e., the Secondary Component Carrier (SCC)) in the source configuration. In such a case, the exchange of measurement targets may cause a meaningless event such as a non-existing serving cell in frequency "serving cell becomes higher than threshold". Such meaningless events, for example, may result in unnecessary measurements at certain frequencies.

Similar problems arise in reconfiguration where the frequency may be part of the source configuration, such as an SCC, but not part of the target configuration. In such a case, the meaningless event would end up in the target configuration, assuming the MeasObject of interest does not involve any exchange.

Embodiments contemplate that the WTRU may be configured with "S-measurement" parameters. The "S-measurement" parameter may be, for example, a quality threshold of the serving cell, which may control whether the WTRU may or may not make intra-frequency, inter-frequency, and inter-RAT neighbor cell measurements. For example, a multi-carrier capable WTRU may refrain from measuring on non-configured frequencies as long as the signal strength of the primary serving cell is above some configured S-measurement. This prevents the network from finally configuring additional CCs for this WTRU.

The measurement configuration may include multiple measurement targets, such as for more than one carrier or frequency. One or more methods may be used to minimize the likelihood that the WTRU generates and transmits multiple measurement reports in a short period of time. By way of example, and not by way of limitation, this may be accomplished through a grouping measurement based on a measurement identification. This may be achieved by applying logical control of the trigger conditions for initiating transmission of the measurement report.

Alternatively, minimizing the likelihood that the WTRU generates and transmits multiple measurement reports in a short period of time may also be accomplished by initiating transmission of one or more different types of reports. For example, at least one of these types may be a report of measurements of only triggered events. Another type may be a report of all measurement packet measurements. Another type may be multiple reports, possibly at the same time, each containing measurements attached to a separate measurement target. This latter type may be distinct from adjacent synchronous transmissions of multiple reports and may have advantages under certain conditions as it may result in a report being transmitted within one Transmission Time Interval (TTI). This typically results in less overhead than transmitting the report in a different TTI.

A measurement identity (measID) may be defined as one or more measurement objects (measObject) (e.g., frequency) associated with a reporting configuration. The reporting configuration may include a standard list and a reporting format.

Embodiments contemplate that multi-carrier operation may be implemented as follows: the measurement identity may additionally be configured with a new parameter (measGroupID) representing the measurement packet, which is itself associated with a type (measGroupType) indicating the trigger function applied to the measurement packet.

The associated trigger function may be one of several types. At least one type of trigger function may be mentioned as a default trigger function. When any one of the configured events belonging to the measurement target of the measurement packet meets the reporting criteria, the WTRU may initiate one or more procedures for transmitting a measurement report for the measurement packet immediately or with a predetermined delay.

At least one type of trigger function may be mentioned as a window-based trigger function. When any configured event belonging to a measurement target of a measurement packet satisfies the reporting criteria, and if there is no pending measurement report for the measurement packet, the WTRU may consider the measurement report pending and may wait for a certain period of time (i.e., a window time). Once the time period ends and there is at least one pending measurement report, the WTRU initiates a procedure to transmit a measurement report for the measurement packet. The size of the window can be a fixed value or can be configured through a network. The configuration may be performed using layer three (L3) signaling, such as Radio Resource Control (RRC).

Embodiments contemplate that at least one type of trigger function may be referred to as a window-based cumulative trigger function. When any configured event belonging to a measurement target of a measurement packet satisfies the reporting criteria, and if there is no pending measurement report for the measurement packet, the WTRU may consider that the measurement report may be pending and may wait for a certain period of time (e.g., a window time). Once the time period ends and if the event criteria for each measurement target of the measurement packet are met, the WTRU initiates a procedure to transmit a measurement report for the measurement packet. For example, the size of the window may be a fixed value or may be configured through the network. By way of example, and not by way of limitation, the configuration may be performed using L3 signaling, such as RRC.

It is also contemplated in embodiments that at least one type of trigger function may be mentioned as a disabled trigger function. When any configured event belonging to the measurement target of a measurement packet satisfies the reporting criteria, the WTRU ignores the event if less than a certain amount of time (the amount of time that elapses from the transmission of the report of the measurement packet as determined by the prohibit timer). For example, the amount of time may be a fixed value or may be configurable over the network. By way of example, and not by way of limitation, the configuration may be performed using L3 signaling, such as RRC.

Embodiments contemplate that at least one type of trigger function may be referred to as a time-to-trigger cascade (cascade) trigger function. The time Tx is defined as the delay before the WTRU initiates the measurement report transmission, i.e., the trigger time, for example. When any configured event belonging to the measurement target of the measurement packet satisfies the reporting criteria, the WTRU starts a first timer corresponding to a value T1, for example. Before the expiration of T1, the WTRU may complete an estimate of other measurement targets in the measurement packet, which may be configured with a second timer T2, where, for example, T2 may be less than T1. Upon expiration of time T1, the WTRU reports the number of measurements that meet the event criteria in the same measurement report transmission.

Each of the values of Tx may be a fixed value or may be configured by the network, for example, using L3 signaling (e.g., RRC). Thus, T1 and T2 may be multiples (multiples) of the measurement opportunity. This can reduce the variation (fluctuation) of the different measurements into the trigger timer.

Embodiments contemplate that a parameter may be included to indicate whether to report only measurements of triggered events. For example, if the parameter value is true, the WTRU may include the number of some or all measurement targets of the measurement packet in the transmission of the measurement report. If the parameter value is not true, the WTRU may only report the number of measurement targets that meet the event criteria. For example, the parameter may be an all-in-group report enabled (alloreportsin groupealed) parameter.

Embodiments contemplate that one or more problems may arise when the signal quality from a carrier is rapidly degraded, or when a handoff to a target cell using multiple carriers is desired. In such an example, the carrier may correspond to a primary serving cell or "Pcell".

In the disclosed examples, the term "metric" may correspond to a quality measurement, for example, without loss of generality, either a received signal quality (e.g., Reference Signal Received Quality (RSRQ) of an LTE system) or a received signal strength (e.g., Reference Signal Received Power (RSRP) of an LTE system). The selection of the measurement metric may be configured on a per frequency basis. For example, RSRP may be used for a first frequency and RSRQ may be used for a second frequency, or vice versa.

The term "primary serving cell" may be used to designate a specific or unique carrier that a WTRU is configured with when the WTRU operates with multiple carriers. For example, the term may correspond to a carrier corresponding to a "special cell" or a "primary serving cell" or a "Pcell". The term "serving cell" may be "primary serving cell" or "Pcell" or "secondary serving cell" or "Scell," for example, and may be used to designate any carrier on which a WTRU is configured on any frequency. The term "best cell" refers to the measured cell with the highest metric on a given frequency, regardless of whether its corresponding carrier is part of the WTRU configuration. Alternatively, the best cell may also refer to the measured cell with the highest metric on a given frequency, which may not be part of the WTRU configuration. This term may be applied to the following exemplary measurement events to support CC management.

For example, embodiments contemplate that when an event or one of a set of events is triggered, the WTRU may send a measurement report or other measurement target that includes measurements from multiple frequencies. The event or set of events may indicate a reconfiguration that needs to be performed. Alternatively, the WTRU may send multiple measurement reports, perhaps each containing measurements or other measurement targets from a single frequency when an event or one of a set of events is triggered. The event or set of events may indicate a reconfiguration that needs to be performed. With this approach, the network can obtain measurements of cells or carriers on other candidate frequencies as reconfigurations immediately or possibly after a predetermined delay.

Embodiments contemplate that the event triggering the measurement report from multiple frequencies may be one or a subset of several types, for example. One example may be an event indicating signal quality degradation on the primary serving cell, such as an a2 event in which the primary serving cell metric may fall below a threshold or an A3 event in which the neighbor cell metric may have a better offset (offset) (e.g., higher) than the primary serving cell metric.

Another example of a triggering event may be an extension of the event in which the primary serving cell may be replaced by a serving cell on a particular frequency. For example, in the extended a2 event, the serving cell metric on a particular frequency may fall below a threshold. As another example, in the extended a3 event, the neighbor cell metrics may have a better offset on a particular frequency than the serving cell metrics. For example, the phrase "having a better offset" may be understood to mean higher or larger. Also by way of example, meaning that "A has a better offset than B" may be understood as the measurement of A being one "offset" value greater than the measurement of B.

Another example of a trigger event may be an event indicating a degradation in signal quality on the first serving cell when the signal quality of the second serving cell remains above a threshold. For example, the primary serving cell metric may fall below a first threshold, and the serving cell metric on a particular frequency may remain above a second threshold. In another example, the serving cell metric on a particular frequency may fall below a first threshold and the serving cell metric on another particular frequency may remain above a second threshold. In yet another example, the neighbor cell metrics may become more offset than the primary serving cell, and the serving cell metrics on a particular frequency may remain above the second threshold. Alternatively, the neighbor cell metrics may become more offset than the serving cell on a particular frequency, and the serving cell metrics on another particular frequency may remain above the second threshold.

Another example of a triggering event may be similar to one or more of the previous examples, but instead of using a primary serving cell or other standard frequency based event, any of a pre-configured set of frequencies may be used instead of using a specific frequency (or a specific standard frequency). The preconfigured set of frequencies may be provided by higher layers or may correspond to a set of frequencies at which the WTRU may be configured to operate.

Upon triggering one of the above events, the measurement report or set of measurement reports transmitted by the WTRU may contain the following measurements of the measurement targets, either individually or in combination: a measurement target of a frequency corresponding to the primary serving cell; all or a subset of measurement targets corresponding to measurement configurations for frequencies on which the WTRU may operate (e.g., Scell-configured frequencies); all or a subset of measurement targets of a measurement configuration corresponding to frequencies on which the WTRU may operate if the serving cell metric is above a threshold; all or a subset of the measurement targets for which the strongest cell metric is above a threshold; on a condition that ignoring the event has been triggered, including all or a subset of measurement targets in a measurement configuration of the WTRU; or all or a subset of the measurement targets used to estimate the event that triggered the report. The measurement target may relate to a type of measurement target (e.g., measObjectEUTRA, measObjectUTRA, measObjectGERAN, or measObjectCDMA 2000).

In the case where only one subset of measurement targets is reported, the number of measurement targets may be determined using one or more of the following: k measurement targets are reached in total; n measurement targets corresponding to the carrier waves configured with the Scell are reached; or to M measurement targets corresponding to carriers not configured with Scell. Thus, measurement results up to C cells may be reported. N, M, C and K may be predefined or signaled by higher layers.

Embodiments contemplate that for the case where the selected number of targets is less than the number of targets available for measurement, the subset of targets may be selected using one or more or a combination of the following: rule 1-select the target with the highest (or best) metric (RSRP/RSRQ) for its highest ranking (rank) cell; and/or rule 2-select a target whose metric of the highest ranking cell is above a threshold. Rule 1 is used if the measurement target selected by rule 2 exceeds the maximum number of allowed measurement targets.

The WTRU may send a measurement report to effect removal of a certain carrier in the configuration or to inform the network that the addition of a certain carrier to the WTRU configuration is no longer considered. The WTRU may send a measurement report when one or several events occur, for example, when the signal strength or quality on a carrier becomes too low for proper operation. Other examples may include when the serving carrier metric on the measurement target falls below an absolute threshold, or when the best cell metric on the measurement target falls below an absolute threshold.

Such a situation may be detected using the following example events: removing a carrier from the WTRU configuration or no longer being considered for addition to the WTRU configuration because its relative quality becomes too low compared to another carrier. Examples include, but are not limited to, serving cell metrics becoming more poorly offset (e.g., lower) than primary serving cell on measurement targets; the best cell metric becomes worse off the primary serving cell on the measurement target; serving cell metrics become more poorly offset on the first measurement target than on the second measurement target; or the best cell metric becomes worse off on the first measurement target than the metric of the serving cell on the second measurement target. For example, the network may configure the use of these events as part of the WTRU's measurement configuration.

Embodiments contemplate that on-demand measurements may be introduced to address the problem of supporting handover to multiple carriers and/or managing configurations and releasing additional carriers in a target cell. The network may request measurements of the cells it is interested in a message, e.g. an on-demand measurement request, or by setting a field in an extension message. The message may be transmitted on a Radio Resource Control (RRC) layer, a Medium Access Control (MAC) layer, or a Physical (PHY) layer as shown in fig. 3. Upon receiving the message, the WTRU sends a measurement report for the indicated carrier frequency or measurement target.

The following terms may be used in the following examples: "source configuration" refers to the RRC configuration of the WTRU prior to the reconfiguration or re-establishment procedure. "target configuration" refers to the RRC configuration of the WTRU after a reconfiguration or re-establishment procedure (if the procedure is successful). "Pcell" refers to a serving cell on a Primary Component Carrier (PCC). "Scell" refers to a serving cell on a Secondary Component Carrier (SCC). A "Scell-referenced (referred) event" may refer to a measurement event such as, but not limited to, a1 or a2 whose serving cell reference is Scell. Embodiments contemplate that a1 may represent a serving cell may become better than a threshold, while a2 may represent a serving cell may become worse than a threshold. The terms and definitions disclosed herein are for illustrative purposes, and other terms disclosed may also be applied as appropriate.

The following examples may be used to prepare the WTRU to reconfigure its measurement configuration for any type of reconfiguration. The WTRU may remove the measId from its measurement configuration before performing the measurement configuration procedure, during an RRC reconfiguration procedure or an RRC reestablishment procedure when at least a subset of the following conditions are met. Conditions for removing the measId may include, but are not limited to, when: a) the measId is linked with the measObject corresponding to the SCC in the source configuration; b) the measId is linked with a measObject corresponding to the SCC in the source configuration but not the SCC in the destination configuration; c) the measId is linked with a measObject corresponding to the SCC in the source configuration, but not the SCC or PCC in the target configuration; d) the measId is linked to the measObject corresponding to the SCC in the source configuration, and the Scell in the target configuration is not the same as the Scell in the source configuration; e) measId is linked with the reporting configuration corresponding to the Scell-reference event; f) measId is linked to the reporting configuration corresponding to the Scell-reference event, and if (a) is true; g) the measId is linked with the reporting configuration corresponding to the Scell-reference event, and if (b) is true; h) the measId is linked with the reporting configuration corresponding to the Scell-reference event, and if (c) is true; i) the measId is linked with the reporting configuration corresponding to the Scell-reference event, and if (d) is true; j) the measId is linked with the measObject corresponding to the non-configured CC in the source configuration; k) the measId is linked with the measObject corresponding to the non-configured CC in the target configuration; and/or l) the measId is linked to a measObject corresponding to a non-configured CC in the source configuration, rather than the SCC or PCC in the target configuration.

Embodiments contemplate that when one of the above conditions is met, the measurement identity (measId) will be (or will only be in some embodiments) removed if at least a subset of the following additional conditions are met: m) according to one or more embodiments described in the following paragraphs, the measId is modified to be linked to a different measObject, or n) the PCC frequency in the source configuration is different from the PCC frequency in the target configuration, e.g. inter-frequency handover.

The following example may be used to prepare a WTRU to reconfigure its measurement configuration for a reconfiguration involving a change in PCC frequency in multi-carrier operation. For example, because the measId may already be linked to the first measObject, the WTRU may modify this measId, thereby allowing the WTRU to link to the second measObject instead during the RRC reconfiguration procedure and/or the RRC reestablishment procedure prior to performing the measurement configuration procedure. The modification may be made when the second measObject is already part of the WTRU measurement configuration and when at least a subset of the following conditions are met: o) the first measObject corresponds to the PCC in the source configuration and the second measObject corresponds to the PCC in the target configuration, and the measId may be linked with a reporting configuration that does not correspond to a Scell-refer event; p) the first measObject corresponds to the PCC in the target configuration and the SCC in the source configuration, and the second measObject corresponds to the PCC in the source configuration and/or the SCC in the target configuration; or the first measObject corresponds to the PCC in the target configuration and/or the non-configured CC in the source configuration and the second measObject corresponds to the PCC in the source configuration and/or the non-configured CC in the target configuration.

Embodiments contemplate that conditional use of s-measurements for non-configured frequencies may be used to perform measurements. For example, the WTRU may make measurements on non-configured frequencies where at least one measId is linked to a corresponding measObject, regardless of the configuration of s-measurements, if at least one of the following conditions is met. The conditions may include, but are not limited to: when the WTRU receives an indication from its measurement configuration to measure on an unconfigured frequency; when a multi-carrier capable WTRU is capable of adding at least one CC in its configuration; and/or when the WTRU is capable of measuring on an unconfigured frequency without using measurement gaps.

Fig. 4 shows an exemplary embodiment. As shown in fig. 4, at 402, a wireless transmit/receive unit (WTRU) may have one or more processors configured, at least in part, to determine a Radio Resource Control (RRC) connected state. At 404, the WTRU may reconfigure the measurement configuration. The reconfiguration of the measurement configuration may include removing at least one parameter from the measurement configuration. At 406, the RRC connection state may be determined to be at least one of an RRC connection reestablishment or an RRC connection reconfiguration, for example. At 408, the WTRU may remove at least one parameter from the measurement configuration, for example, during at least one of an RRC connection reestablishment or an RRC connection reconfiguration. Alternatively, at 410, the WTRU may be further configured to remove at least one parameter from the measurement configuration based on at least one condition. Embodiments contemplate that the at least one parameter may correspond to an identification parameter, such as a measId parameter. Also, for example, the first instance may include a measId parameter associated with at least one of an a1 measurement event or an a2 measurement event. At 412, the WTRU may be further configured to remove the at least one parameter from the measurement configuration based on both the first condition and the second condition. For example, embodiments contemplate that the second condition may include a measId parameter associated with a measObject parameter corresponding to a non-configured Component Carrier (CC).

As shown in fig. 5 and 5A, embodiments contemplate that a wireless transmit/receive unit (WTRU) may include one or more processors. At 502, at least one processor of the WTRU (or WTRU only) may be configured, at least in part, to configure measurement reporting. The measurement report may be configured according to at least one condition. The measurement report may include measurements on one or more frequencies on which the WTRU may be configured to operate. At 504, the WTRU may be configured to transmit the measurement report. At 506, the measurement report may include measurements on one or more frequencies on which the WTRU may be configured to operate other than the first frequency. The first frequency may be associated with at least one condition. At 508, the at least one condition may include a signal quality of the first cell on the first frequency becoming below a first threshold. The at least one condition may also include a signal quality of a second cell on the one or more frequencies on which the WTRU may be configured to operate other than the first frequency being above a second threshold.

Alternatively, at 510, the at least one condition may include a first quality measurement associated with a first cell serving the WTRU at a first frequency becoming below a first threshold and a second quality measurement being above a second threshold. The second quality measurement may be associated with a second cell on the one or more frequencies on which the WTRU may be configured to operate different from the first frequency.

Alternatively, at 512, the at least one condition may include a first quality measurement associated with a first cell on a first frequency becoming below a first threshold and a second quality measurement being above a second threshold. The second quality measurement may be associated with a second cell on the one or more frequencies on which the WTRU may be configured to operate different from the first frequency.

In another alternative embodiment, at 514, the at least one condition may include a first quality measurement associated with a first cell serving the WTRU at a first frequency becoming lower than a second quality measurement associated with a second cell adjacent to the first cell. The at least one condition may also include the third quality measurement being above a threshold. The third quality measurement may be associated with a third cell on the one or more frequencies on which the WTRU may be configured to operate other than the first frequency.

Still alternatively, at 516, the at least one condition may include a first quality measurement associated with a first cell on a first frequency becoming lower than a second quality measurement associated with a second cell adjacent to the first cell. The at least one condition may also include the third quality measurement being above a threshold. The third quality measurement may be associated with a third cell on the one or more frequencies on which the WTRU may be configured to operate other than the first frequency.

Referring now to fig. 6, embodiments contemplate that a wireless transmit/receive unit (WTRU) may include one or more processors. At 602, at least one processor of a WTRU (or WTRU only) may be configured, at least in part, to determine at least one condition associated with one or more cells (or serving cells). The WTRU may be configured to operate on at least one of the one or more cells. At 604, the WTRU may be configured to transmit a measurement report based on the at least one condition. At 606, the at least one condition may be configured to include a quality measure associated with at least one of the at least one or more cells becoming below a threshold. Embodiments contemplate that the threshold may be an absolute threshold. Also, for example, the quality measure may be at least one of a signal strength or a signal quality. At 608, the WTRU may be configured to operate on at least one of the one or more cells on one or more frequencies. For example, embodiments contemplate that the one or more cells may include at least one of a primary serving cell or a secondary serving cell.

Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature can be used alone or in any combination with other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer readable media include electronic signals (transmitted over wired or wireless connections) and computer readable storage media. Examples of computer readable media include, but are not limited to, Read Only Memory (ROM), Random Access Memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims (20)

1. A wireless transmit/receive unit (WTRU), comprising:

a processor configured, at least in part, to:

determining a Radio Resource Control (RRC) connected state; and

the measurement configuration is reconfigured.

2. The WTRU of claim 1, wherein the reconfiguration of the measurement configuration includes removing at least one parameter from the measurement configuration.

3. The WTRU of claim 2, wherein the RRC connection state is determined to be at least one of an RRC connection reestablishment or an RRC connection reconfiguration.

4. The WTRU of claim 3, wherein the processor is further configured to remove the at least one parameter from the measurement configuration during at least one of the RRC connection reestablishment or the RRC connection reconfiguration.

5. The WTRU of claim 4, wherein the processor is further configured to remove the at least one parameter from the measurement configuration based on at least one condition.

6. The WTRU of claim 5, wherein the at least one parameter corresponds to a measurement identity parameter.

7. The WTRU of claim 6, wherein a first condition includes the measurement identity parameter being associated with at least one of an A1 measurement event or an A2 measurement event.

8. The WTRU of claim 7, wherein the processor is further configured to remove the at least one parameter from the measurement configuration according to both the first condition and a second condition, the second condition including the measurement identity parameter being associated with a measurement target parameter corresponding to a non-configured Component Carrier (CC).

9. A wireless transmit/receive unit (WTRU), comprising:

a processor configured, at least in part, to:

configuring a measurement report including measurements on one or more frequencies on which the WTRU is configurable to operate according to at least one condition; and

transmitting the measurement report.

10. The WTRU of claim 9, wherein the measurement report includes measurements on one or more frequencies different from a first frequency on which the WTRU may be configured to operate, the first frequency being associated with the at least one condition.

11. The WTRU of claim 10, wherein the at least one condition includes a signal quality of a first cell on the first frequency becoming below a first threshold and a signal quality of a second cell on the one or more frequencies on which the WTRU is configurable to operate other than the first frequency being above a second threshold.

12. The WTRU of claim 10, wherein the at least one condition includes a first quality measurement associated with a first cell serving the WTRU at the first frequency becoming below a first threshold and a second quality measurement being above a second threshold, the second quality measurement associated with a second cell on the one or more frequencies on which the WTRU is configurable to operate different from the first frequency.

13. The WTRU of claim 10, wherein the at least one condition includes a first quality measurement associated with a first cell on the first frequency becoming below a first threshold and a second quality measurement being above a second threshold, the second quality measurement associated with a second cell on the one or more frequencies on which the WTRU is configurable to operate other than the first frequency.

14. The WTRU of claim 10, wherein the at least one condition includes a first quality measurement associated with a first cell serving the WTRU at the first frequency becoming lower than a second quality measurement associated with a second cell adjacent to the first cell, and a third quality measurement associated with a third cell on the one or more frequencies on which the WTRU is configurable to operate other than the first frequency being higher than a threshold.

15. The WTRU of claim 10, wherein the at least one condition includes a first quality measurement associated with a first cell on the first frequency becoming lower than a second quality measurement associated with a second cell adjacent to the first cell, and a third quality measurement associated with a third cell on the one or more frequencies on which the WTRU is configurable to operate other than the first frequency being higher than a threshold.

16. A wireless transmit/receive unit (WTRU), comprising:

a processor configured, at least in part, to:

determining at least one condition associated with one or more cells on which the WTRU may be configured to operate; and

transmitting a measurement report according to the at least one condition.

17. The WTRU of claim 16, wherein the at least one condition includes a quality measurement associated with at least one of the one or more cells becoming below a threshold.

18. The WTRU of claim 17, wherein the quality measure is at least one of signal strength or signal quality.

19. The WTRU of claim 17, wherein the WTRU is configurable to operate on the at least one of the one or more cells on one or more frequencies.

20. The WTRU of claim 19, wherein the one or more cells include at least one of a primary serving cell or a secondary serving cell.