JP6076987B2 - SRS optimization for multipoint coordinated transmission and reception - Google Patents

Description

  [0001] Certain aspects of the present disclosure relate generally to wireless communications, and more particularly for power control and user multiplexing for multipoint coordinated (CoMP) transmission and reception in heterogeneous networks (HetNet). Regarding the technique.

  [0002] Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and so on. These wireless networks can be multiple access networks that can support multiple users by sharing available network resources. Examples of such multiple access networks include code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, and single carrier FDMA ( SC-FDMA) network.

  [0003] A wireless communication network may include a number of base stations (BSs) that can support communication for a number of user equipments (UEs). A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

  [0004] A base station may transmit data and control information on the downlink and / or receive data and control information on the uplink from the UE. On the downlink, in the transmission from the base station, interference may be recognized due to the transmission from the adjacent base station. On the uplink, transmissions from the UE may cause interference with transmissions from other UEs communicating with neighboring base stations. Interference can degrade performance on both the downlink and uplink.

  [0005] Certain aspects of the present disclosure provide a method for wireless communication by a user equipment (UE). The method generally transmits a first sounding reference signal (SRS) currently served to a UE and intended for a first one or more base stations associated with a first cell identifier. And transmitting a second SRS intended for the second one or more base stations associated with the second cell identifier, and using a separate power control scheme for the first and second Adjusting the transmission power of the SRS.

  [0006] Certain aspects of the present disclosure provide a method for wireless communication by a base station (BS). The method generally serves to transmit a first sounding reference signal (SRS) that is currently serving a UE and is intended for a first one or more base stations associated with a first cell identifier. Configuring a user equipment (UE); configuring the UE to transmit a second SRS directed to a second one or more base stations associated with a second cell identifier; Sending one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS using separate power control schemes.

  [0007] Certain aspects of the present disclosure provide an apparatus for wireless communication by a user equipment (UE). The apparatus generally transmits a first sounding reference signal (SRS) that is currently serving the UE and is intended for the first one or more base stations associated with the first cell identifier, Transmitting a second SRS intended for the second one or more base stations associated with the two cell identifiers and adjusting the transmission power of the first and second SRS using separate power control schemes At least one processor configured to, and a memory coupled to the at least one processor.

  [0008] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first base station. The apparatus is generally serving the UE and is configured to transmit a first sounding reference signal (SRS) intended for the first one or more base stations associated with the first cell identifier. Configure the user equipment (UE), configure the UE to transmit a second SRS directed to a second one or more base stations associated with a second cell identifier, and separate power control At least one processor configured to send one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS using the scheme; And a memory coupled to one processor.

  [0009] Certain aspects of the present disclosure provide a computer program product comprising a computer-readable medium having instructions stored thereon. The instructions generally transmit a first sounding reference signal (SRS) that is currently serving the UE and is intended for the first one or more base stations associated with the first cell identifier. Transmitting a second SRS intended for the second one or more base stations associated with the second cell identifier and using a separate power control scheme for the first and second SRS It can be performed by one or more processors for adjusting the transmit power.

  [0010] Certain aspects of the present disclosure provide a computer program product comprising a computer-readable medium having instructions stored thereon. The instructions are generally to serve the UE and send a first sounding reference signal (SRS) intended for the first one or more base stations associated with the first cell identifier. Configuring a user equipment (UE); configuring the UE to transmit a second SRS directed to a second one or more base stations associated with a second cell identifier; One or more for sending one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS using separate power control schemes Can be executed by other processors.

[0011] FIG. 1 is a block diagram conceptually illustrating an example of a wireless communication network, in accordance with certain aspects of the present disclosure. [0012] FIG. 1 is a block diagram conceptually illustrating an example frame structure in a wireless communication network, in accordance with certain aspects of the present disclosure. [0013] FIG. 4 illustrates an example format for uplink in Long Term Evolution (LTE) according to certain aspects of the present disclosure. [0014] FIG. 4 is a block diagram conceptually illustrating an example of a Node B communicating with a user equipment device (UE) in a wireless communication network, in accordance with certain aspects of the present disclosure. [0015] FIG. 4 illustrates an example heterogeneous network (HetNet) in accordance with certain aspects of the present disclosure. [0016] FIG. 4 illustrates an example resource partition in a heterogeneous network according to some aspects of the present disclosure. [0017] FIG. 4 illustrates an exemplary collaborative partitioning of subframes in a heterogeneous network, in accordance with certain aspects of the present disclosure. [0018] FIG. 4 shows a range-extended cellular region in a heterogeneous network. [0019] FIG. 4 illustrates a network having a macro eNB and a remote radio head (RRH), according to some aspects of the present disclosure. [0020] FIG. 4 illustrates an exemplary sounding reference signal (SRS) extension, according to aspects of the disclosure. [0021] FIG. 6 illustrates another example sounding reference signal (SRS) extension according to aspects of the disclosure. [0022] FIG. 10 illustrates example operations 1100 performed at a user equipment (UE) in accordance with certain aspects of the present disclosure. [0023] FIG. 7 is a drawing illustrating exemplary operations 1200 performed at a base station (eg, and eNB) in accordance with certain aspects of the present disclosure.

  [0024] Aspects of the present disclosure provide techniques that can enhance a sounding reference signal (SRS) procedure for use in a multi-point coordination (CoMP) system. As described in more detail below, UEs involved in CoMP operation may be configured to send two different sets of SRS signals. For example, a first set of SRS may be targeted only for the serving cell, while a second set of SRS may be targeted for joint reception of multiple cells.

  [0025] The techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000. UTRA includes Wideband CDMA (WCDMA®) and other variants of CDMA. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). The OFDMA network includes evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20. Wireless technology such as Flash-OFDM (registered trademark) can be implemented. UTRA and E-UTRA are part of the Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, certain aspects of the techniques are described below for LTE, and LTE terminology is used in much of the description below.

Example wireless network
[0026] FIG. 1 shows a wireless communication network 100, which may be an LTE network. The wireless network 100 may include a number of evolved Node B (eNB) 110 and other network entities. An eNB may be a station that communicates with user equipment devices (UEs) and may also be referred to as a base station, Node B, access point, and so on. Each eNB 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” may refer to an eNB's coverage area and / or an eNB subsystem serving this coverage area, depending on the context in which the term is used.

  [0027] An eNB may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or other types of cell. The macro cell covers a relatively large geographic area (eg, a few kilometers in radius) and allows unrestricted access by UEs with service subscription. A pico cell covers a relatively small geographic area and allows unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (eg, home) and a UE that has an association with the femto cell (eg, a UE in a Closed Subscriber Group (CSG), a user at home) Limited access by a UE for example). An eNB for a macro cell may be referred to as a macro eNB (ie, a macro cell base station). An eNB for a pico cell may be referred to as a pico eNB (ie, a pico base station). An eNB for a femto cell is referred to as a femto eNB (ie, a femto base station) or a home eNB. In the example shown in FIG. 1, eNBs 110a, 110b, and 110c may be macro eNBs for macro cells 102a, 102b, and 102c, respectively. eNB 110x may be a pico eNB for pico cell 102x. eNBs 110y and 110z may be femto eNBs for femto cells 102y and 102z, respectively. An eNB may support one or multiple (eg, three) cells.

  [0028] The wireless network 100 may also include relay stations. A relay station receives a transmission of data and / or other information from an upstream station (eg, eNB or UE) and transmits a transmission of that data and / or other information to a downstream station (eg, UE or eNB) Station. A relay station may also be a UE that relays transmissions to other UEs. In the example shown in FIG. 1, relay station 110r may communicate with eNB 110a and UE 120r to facilitate communication between eNB 110a and UE 120r. A relay station may be called a relay eNB, a relay, or the like.

  [0029] The wireless network 100 may be a heterogeneous network (HetNet) that includes various types of eNBs, eg, macro eNBs, pico eNBs, femto eNBs, relays, and so on. These different types of eNBs may have different impacts on different transmit power levels, different coverage areas, and interference in the wireless network 100. For example, a macro eNB may have a high transmission power level (eg, 20 watts), while a pico eNB, a femto eNB, and a relay may have a lower transmission power level (eg, 1 watt).

  [0030] The wireless network 100 may support synchronous or asynchronous operation. For synchronous operation, the eNB may have similar frame timing and transmissions from different eNBs may be approximately time aligned. For asynchronous operation, eNBs may have different frame timings and transmissions from different eNBs may not be time aligned. The techniques described herein may be used for both synchronous and asynchronous operations.

  [0031] Network controller 130 may couple to a set of eNBs and coordinate and control these eNBs. Network controller 130 may communicate with eNB 110 via a backhaul. The eNBs 110 may also communicate with each other directly or indirectly via, for example, a wireless backhaul or wireline backhaul.

  [0032] UE 120 may be distributed throughout wireless network 100, and each UE may be fixed or mobile. A UE may also be referred to as a terminal, a mobile station, a subscriber unit, a station, and so on. A UE may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, and the like. A UE may be able to communicate with macro eNBs, pico eNBs, femto eNBs, relays, and the like. In FIG. 1, a solid line with double arrows indicates a desired transmission between a UE and a serving eNB, which is an eNB designated to serve the UE, on the downlink and / or uplink. A broken line with a double arrow indicates interference transmission between the UE and the eNB. For some aspects, the UE may include an LTE Release 10 UE.

  [0033] LTE utilizes orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. Use. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, K may be equal to 128, 256, 512, 1024, or 2048, respectively, for a system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz). The system bandwidth can also be divided into subbands. For example, the subband may cover 1.08 MHz, one, two, four, eight, or sixteen for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively. There may be subbands.

  [0034] FIG. 2 shows a frame structure used in LTE. The downlink transmission timeline can be divided into radio frame units. Each radio frame may have a predetermined duration (eg, 10 milliseconds (ms)) and can be partitioned into 10 subframes with indices from 0 to 9. Each subframe may include two slots. Thus, each radio frame may include 20 slots with indices from 0 to 19. Each slot has L symbol periods, eg, L = 7 symbol periods for a regular cyclic prefix (as shown in FIG. 2), or L = 6 symbols for an extended cyclic prefix. A period can be included. An index of 0-2L-1 may be assigned to 2L symbol periods in each subframe. The available time frequency resources can be divided into resource blocks. Each resource block may cover N subcarriers (eg, 12 subcarriers) in one slot.

  [0035] In LTE, an eNB may send a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) for each cell in the eNB. The primary synchronization signal and the secondary synchronization signal may be sent in symbol periods 6 and 5, respectively, in subframes 0 and 5 of each radio frame with a normal cyclic prefix, respectively, as shown in FIG. . The synchronization signal may be used by the UE for cell detection and acquisition. The eNB may send a physical broadcast channel (PBCH) in symbol periods 0 to 3 in slot 1 of subframe 0. PBCH may carry certain system information.

  [0036] The eNB may send a Physical Control Format Indicator Channel (PCFICH) during the first symbol period of each subframe, as shown in FIG. PCFICH may carry the number of symbol periods (M) used for the control channel, where M may be equal to 1, 2, or 3, and may vary from subframe to subframe. M may also be equal to 4 for a small system bandwidth, eg, with less than 10 resource blocks. The eNB may send a physical HARQ indicator channel (PHICH) and a physical downlink control channel (PDCCH) during the first M symbol periods of each subframe (see FIG. 2). Not shown). The PHICH may carry information to support a hybrid automatic repeat request (HARQ). The PDCCH may carry information on resource allocation for the UE and control information for the downlink channel. The eNB may send a physical downlink shared channel (PDSCH) during the remaining symbol periods of each subframe. The PDSCH may carry data for UEs scheduled for data transmission on the downlink. Various signals and channels in LTE are described in the published 3GPP TS 36.211 entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation”.

  [0037] The eNB may send PSS, SSS, and PBCH at the center 1.08 MHz of the system bandwidth used by the eNB. The eNB may send PCFICH and PHICH across the entire system bandwidth during each symbol period during which these channels are sent. The eNB may send PDCCH to a group of UEs in some part of the system bandwidth. An eNB may send a PDSCH to a specific UE in a specific part of the system bandwidth. The eNB may send PSS, SSS, PBCH, PCFICH and PHICH to all UEs in a broadcast manner, may send PDCCH to a specific UE in a unicast manner, and may send PDSCH to a specific UE in a unicast manner.

  [0038] Several resource elements may be available in each symbol period. Each resource element may cover one subcarrier in one symbol period and may be used to send one modulation symbol that may be real or complex valued. Resource elements that are not used for the reference signal in each symbol period may be placed in a resource element group (REG). Each REG may include four resource elements in one symbol period. The PCFICH may occupy four REGs that may be approximately equally spaced across the frequency in symbol period 0. The PHICH may occupy three REGs that may be spread across the frequency in one or more configurable symbol periods. For example, the three REGs for PHICH can all belong to symbol period 0 or can be spread into symbol periods 0, 1, and 2. The PDCCH may occupy 9, 18, 32, or 64 REGs that may be selected from the available REGs during the first M symbol periods. Only some combinations of REGs may be enabled for PDCCH.

  [0039] The UE may know the specific REG used for PHICH and PCFICH. The UE may search for various combinations of REGs for PDCCH. The number of combinations to search is generally less than the number of combinations enabled for PDCCH. The eNB may send the PDCCH to the UE in any of the combinations that the UE will search.

  [0040] FIG. 2A shows an exemplary format 200A for the uplink in LTE. The available resource blocks for the uplink can be divided into a data section and a control section. The control section may be formed at two edges of the system bandwidth and may have a configurable size. Resource blocks in the control section may be allocated to the UE for transmitting control information. The data section may include all resource blocks that are not included in the control section. The design of FIG. 2A results in a data section that includes consecutive subcarriers that may allow all consecutive subcarriers in the data section to be assigned to a single UE.

  [0041] In order to send control information to the eNB, UEs may be allocated to resource blocks in the control section. The UE may also be assigned resource blocks in the data section to transmit data to the eNB. The UE may send control information over physical uplink control channels (PUCCH) 210a, 210b in allocated resource blocks in the control section. The UE may transmit data only or both data and control information in physical uplink shared channels (PUSCH) 220a, 220b on assigned resource blocks in the data section. Uplink transmission may be across both slots of the subframe and may hop across the frequency as shown in FIG. 2A.

  [0042] A UE may be within the coverage of multiple eNBs. One of these eNBs may be selected to serve the UE. The serving eNB may be selected based on various criteria such as received power, path loss, signal to noise ratio (SNR).

  [0043] The UE may operate in a dominant interference scenario where the UE may see significant interference from one or more interfering eNBs. The dominant interference scenario may occur due to limited association. For example, in FIG. 1, UE 120y may be proximate to femto eNB 110y and may have a high received power for eNB 110y. However, UE 120y may not be able to access femto eNB 110y due to limited association, and then macro eNB 110c with lower received power (as shown in FIG. 1) or also lower received power. It may be connected to a femto eNB 110z (not shown in FIG. 1). In that case, UE 120y may see high interference from femto eNB 110y on the downlink and may cause high interference to eNB 110y on the uplink.

  [0044] A dominant interference scenario may also occur due to range extension, which is a scenario where a UE connects to an eNB with a lower path loss and a lower SNR among all eNBs detected by the UE. It is. For example, in FIG. 1, UE 120x may detect macro eNB 110b and pico eNB 110x, and may have lower received power for eNB 110x than eNB 110b. Nevertheless, if the path loss of eNB 110x is lower than the path loss of macro eNB 110b, it may be desirable for UE 120x to connect to pico eNB 110x. This may reduce interference to the wireless network for a given data rate of UE 120x.

  [0045] In an aspect, communication in a dominant interference scenario may be supported by operating different eNBs on different frequency bands. A frequency band is a frequency range that can be used for communication, and can be given by (i) a center frequency and bandwidth, or (ii) a lower frequency and a higher frequency. A frequency band is sometimes called a band, a frequency channel, or the like. The frequency bands for different eNBs may be selected such that a UE can communicate with a weaker eNB in a dominant interference scenario while allowing a strong eNB to communicate with its UE. An eNB may be classified as a “weak” eNB or “strong” eNB (based on the eNB's transmit power level) based on the received power of the signal from the eNB received at the UE.

  [0046] FIG. 3 is a block diagram of a design of a base station or eNB 110, which may be one of the base stations / eNBs of FIG. 1, and UE 120, which may be one of the UEs of FIG. For the restricted association scenario, eNB 110 may be macro eNB 110c of FIG. 1 and UE 120 may be UE 120y. The eNB 110 may also be some other type of base station. eNB 110 may be equipped with T antennas 334a through 334t, and UE 120 may be equipped with R antennas 352a through 352r, where T ≧ 1 and R ≧ 1.

  [0047] At eNB 110, transmit processor 320 may receive data from data source 312 and receive control information from controller / processor 340. The control information may be for PBCH, PCFICH, PHICH, PDCCH, etc. The data may be for PDSCH and the like. Transmit processor 320 may process (eg, encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. Transmit processor 320 may also generate reference symbols for PSS, SSS, and cell specific reference signals, for example. A transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (eg, precoding) on the data symbols, control symbols, and / or reference symbols, where applicable, The output symbol stream may be provided to T modulators (MODs) 332a through 332t. Each modulator 332 may process a respective output symbol stream (eg, for OFDM) to obtain an output sample stream. Each modulator 332 may further process (eg, convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 332a through 332t may be transmitted via T antennas 334a through 334t, respectively.

  [0048] At UE 120, antennas 352a-352r may receive downlink signals from eNB 110 and may provide received signals to demodulators (DEMODs) 354a-354r, respectively. Each demodulator 354 may adjust (eg, filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 354 may further process input samples (eg, OFDM) to obtain received symbols. MIMO detector 356 may obtain received symbols from all R demodulators 354a-354r, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. Receive processor 358 processes (eg, demodulates, deinterleaves, and decodes) the detected symbols, provides decoded data of UE 120 to data sink 360, and provides decoded control information to controller / processor 380. obtain.

  [0049] On the uplink, at UE 120, transmit processor 364 may receive and process data (eg, for PUSCH) from data source 362 and from controller / processor 380 (eg, for PUCCH). ) Control information can be received and processed. Transmit processor 364 may also generate reference symbols for the reference signal. Symbols from transmit processor 364 may be precoded by TX MIMO processor 366, where applicable, and further processed by modulators 354a-354r (eg, for SC-FDM, etc.) and transmitted to eNB 110. At eNB 110, the uplink signal from UE 120 is received by antenna 334, processed by demodulator 332, detected by MIMO detector 336 when applicable, and further processed by receive processor 338 to provide UE 120 The decrypted data and control information sent by can be obtained. The receiving processor 338 may provide the decoded data to the data sink 339 and the decoded control information to the controller / processor 340.

  [0050] Controllers / processors 340 and 380 may direct the operation at eNB 110 and the operation at UE 120, respectively. Controller / processor 340, receiving processor 338, and / or other processors and modules at eNB 110 may perform or direct operations and / or processes for the techniques described herein. Memories 342 and 382 may store data and program codes for eNB 110 and UE 120, respectively. A scheduler 344 may schedule UEs for data transmission on the downlink and / or uplink.

Example resource category
[0051] According to some aspects of the present disclosure, when a network supports enhanced inter-cell interference coordination (eICIC), a base station may allow an interfering cell to share some of its resources. To reduce or eliminate interference by giving up, resources can be negotiated with each other to coordinate. With this interference coordination, the UE may be able to access the serving cell even when there is severe interference due to using resources provided by the interfering cell.

  [0052] For example, a femto cell in limited access mode (ie, only member femto UEs can access this cell) in the coverage area of an open macro cell effectively introduces resources and eliminates interference By doing so, it may be possible to create a “coverage hole” for the macro cell (within the coverage area of the femto cell). By negotiating that the femto cell provides resources, the macro UEs under the femto cell coverage area may still be able to access the UE's serving macro cell using these provided resources.

  [0053] In a radio access system using OFDM, such as Evolved Universal Terrestrial Radio Access Network (E-UTRAN), the resulting resources may be time-based, frequency-based, or a combination of both. When the coordinated resource partition is time based, the interfering cell may simply not use some of the subframes in the time domain. When the coordinated resource partition is frequency based, the interfering cell may result in subcarriers in the frequency domain. With a combination of both frequency and time, the interfering cell can provide frequency and time resources.

  [0054] In FIG. 4, an eICIC may support a macro UE 120y that supports eICIC (eg, FIG. 4) even when the macro UE 120y is experiencing severe interference from the femtocell y, as indicated by the solid radio link 402. 6 illustrates an example scenario that may allow a Rel-10 macro UE) as shown in FIG. Legacy macro UE 120u (eg, Rel-8 macro UE as shown in FIG. 4) cannot access macrocell 110c under severe interference from femtocell 110y, as indicated by dashed radio link 404. There is. Femto UE 120v (eg, a Rel-8 femto UE as shown in FIG. 4) may access femtocell 110y without any interference issues from macrocell 110c.

  [0055] According to some aspects, the network may support eICIC and there may be various sets of partition information. The first of these sets may be referred to as semi-static resource partitioning information (SRPI). The second of these sets may be referred to as adaptive resource partitioning information (ARPI). Literally, SRPI generally does not change frequently and SRPI may be sent to the UE, so the UE can use the resource partition information for its own operation.

[0056] As an example, resource partitioning may be implemented with a periodicity of 8ms (8 subframes) or a periodicity of 40ms (40 subframes). According to some aspects, it may be assumed that frequency division duplex (FDD) may also be applied so that frequency resources may also be partitioned. For communication via the downlink (eg, from cell node B to UE), the partition pattern is a known subframe (eg, system frame number (SFN) that is a multiple of an integer N such as 4). ) In the first subframe of each radio frame having a value). Such mapping can be applied to determine resource partition information (RPI) for a particular subframe. As an example, the subframes subject to cooperative resource partitioning for the downlink (eg, caused by an interfering cell) may be identified by the following index.

[0058] For the uplink, the SRPI mapping may be shifted by, for example, 4 ms. Thus, examples for the uplink may include:

  [0060] SRPI may use the following three values for each entry:

  [0061] U (use): This value indicates that the subframe is being cleaned up from the dominant interference to be used by this cell (ie, the primary interfering cell does not use this subframe) Indicates.

  [0062] N (not used): This value indicates that the subframe is not used.

  [0063] X (Unknown): This value indicates that the subframe is not statically partitioned. Details of the resource usage negotiation between base stations are not known to the UE.

  [0064] Another possible set of parameters for SRPI may be:

  [0065] U (use): This value indicates that the subframe has been cleaned up from the dominant interference to be used by this cell (ie, the main interfering cell does not use this subframe). Indicates.

  [0066] N (not used): This value indicates that the subframe is not used.

  [0067] X (Unknown): This value indicates that the subframe is not statically segmented (details of resource usage negotiation between base stations are not known to the UE).

  [0068] C (Common): This value may indicate that all cells may use this subframe without resource partitioning. This subframe may be subject to interference, so the base station may choose to use this subframe only for UEs that are not experiencing severe interference.

  [0069] The serving cell's SRPI may be broadcast over the air. In E-UTRAN, the SRPI of the serving cell may be sent in a master information block (MIB) or one of the system information blocks (SIB). Predefined SRPI may be defined based on the characteristics of cells, eg, macro cells, pico cells (for open access), and femto cells (for limited access). In such cases, over-the-air broadcasts can be made more efficient as a result of SRPI encoding in system overhead messages.

  [0070] The base station may also broadcast the neighbor cell's SRPI in one of the SIBs. In this case, the SRPI may be sent using its corresponding range of physical cell identifiers (PCI).

  [0071] ARPI may represent additional resource partition information with detailed information about the "X" subframe in SRPI. As described above, detailed information about the “X” subframe is generally known only to the base station, and the UE does not know it.

  [0072] FIGS. 5 and 6 show examples of SRPI assignment in a scenario using macro cells and femto cells. A U, N, X or C subframe is a subframe corresponding to a U, N, X or C SRPI assignment.

  [0073] FIG. 7 is a diagram 700 illustrating a range-extended cellular region in a heterogeneous network. A lower power class eNB, such as RRH 710b, is extended from cellular region 702 through enhanced inter-cell interference coordination between RRH 710b and macro eNB 710a and through interference cancellation performed by UE 720. Cell region 703 may be provided. In extended inter-cell interference coordination, the RRH 710b receives information on the interference state of the UE 720 from the macro eNB 710a. With this information, RRH 710b may service UE 720 in range-extended cellular region 703 and accept UE 720 handoff from macro eNB 710a when UE 720 enters range-extended cellular region 703. it can.

  [0074] FIG. 8 is a diagram illustrating a network 800 that includes a macro node and a number of remote radio heads (RRHs) in accordance with certain aspects of the present disclosure. Macronode 802 is connected to RRHs 804, 806, 808 and 810 using optical fibers. In some aspects, the network 800 may be a homogeneous network or a heterogeneous network, and the RRHs 804-810 may be low power or high power RRHs. In one aspect, the macro node 802 handles all scheduling in the cell for itself and RRH. The RRH may be configured with the same cell identifier (ID) as the macro node 802 or with a different cell ID. If the RRH is configured with the same cell ID, the macro node 802 and the RRH can operate as essentially one cell controlled by the macro node 802. On the other hand, if the RRH and the macro node 802 are configured with different cell IDs, the macro node 802 and the RRH will still be all controlled and scheduled by the macro node 802, but appear to be different cells for the UE. Looks like. It should be further appreciated that the processing for macro node 802 and RRH 804, 806, 808, 810 need not necessarily reside in the macro node. The process may be performed centrally in any other network device or entity connected to the macro and RRH.

  [0075] As used herein, the term transmission point / reception point ("TxP") generally refers to at least one central entity that may have the same or different cell IDs. Refers to geographically separated transmitting / receiving nodes controlled by (e.g., eNodeB).

  [0076] In some aspects, when each of the RRHs shares the same cell ID as the macro node 802, control information is transmitted from the macro node 802 or from both the macro node 802 and all RRHs using CRS. Can be done. A CRS is typically transmitted from each of the transmission points using the same resource elements, so the signals collide. When each transmission point has the same cell ID, the CRS transmitted from each transmission point may not be identified. In some aspects, when the RRH has different cell IDs, CRS transmitted from each of the TxPs using the same resource element may or may not collide. Even if the RRH has different cell IDs and the CRS collides, the advanced UE can identify the CRS transmitted from each of the TxPs using interference cancellation techniques and advanced receiver processing.

  [0077] In some aspects, when all transmission points are configured with the same cell ID and the CRS is transmitted from all transmission points, appropriate antenna virtualization may be used for transmitting macro nodes and / or RRHs. This is necessary when there are an unequal number of physical antennas in. That is, CRS should be transmitted using an equal number of CRS antenna ports. For example, if node 802 and RRH 804, 806, 808 each have four physical antennas and RRH 810 has two physical antennas, the first antenna of RRH 810 uses two CRS ports. The second antenna of RRH 810 may be configured to transmit using two different CRS ports. Alternatively, for the same deployment, macro 802 and RRH 804, 806, 808 can transmit only two CRS antenna ports from a selected two of the four transmit antennas per transmission point. Based on these examples, it should be appreciated that the number of antenna ports may be increased or decreased with respect to the number of physical antennas.

  [0078] As explained above, when all transmission points are configured with the same cell ID, the macro node 802 and the RRHs 804-810 can all transmit CRS. However, if only the macro node 802 transmits a CRS, an outage occurs near the RRH due to automatic gain control (AGC) problems. In such a scenario, CRS-based transmissions from macro 802 may be received with low received power, while other transmissions originating from nearby RRHs are received with much higher power. there is a possibility. This power imbalance can lead to the aforementioned AGC problem.

  [0079] In summary, in general, the difference between the same and different cell ID setups is related to control and legacy issues, as well as other potential operations that depend on CRS. CRS configuration scenarios with different cell IDs but colliding may have similarities with the same cell ID setup, and of course have CRS colliding. Scenarios with different cell IDs and colliding CRSs are generally easier to identify system characteristics / components (eg, scrambled sequences, etc.) that depend on cell IDs compared to the case of the same cell ID. Has the advantage of gaining.

  [0080] The example configurations are applicable to macro / RRH setups with the same or different cell IDs. For different cell IDs, the CRS may be configured to collide, which may lead to similar scenarios for the same cell ID, but system characteristics that depend on the cell ID (eg, scramble Sequence etc.) has the advantage that it can be more easily identified by the UE.

  [0081] In some aspects, an exemplary macro / RRH entity may provide control / data transmission separation within the transmission point of this macro / RRH setup. When the cell ID is the same for each transmission point, PDCCH can be transmitted with CRS from either macro node 802 or from both macro node 802 and RRH 804-810, while PDSCH is a subset of transmission points. To the channel state information reference signal (CSI-RS) and the demodulation reference signal (DM-RS). When the cell ID is different for several transmission points, the PDCCH may be transmitted with CRS in each cell ID group. CRS transmitted from each cell ID group may or may not collide. The UE may not identify CRS transmitted from multiple transmission points with the same cell ID, but may detect CRS transmitted from multiple transmission points with different cell IDs (eg, interference cancellation or similar techniques). Can be identified).

  [0082] In some aspects, if all transmission points are configured with the same cell ID, the control / data transmission separation allows the UE to transmit control based on CRS transmissions from all transmission points. An unrecognized UE may be associated with at least one transmission point for data transmission. This allows cell splitting for data transmission across different transmission points while keeping the control channel common. The term “association” above means configuring an antenna port for a particular UE for data transmission. This is different from the association performed in the handover situation. Control may be transmitted based on CRS as described above. By separating control and data, it may be possible to reconfigure the antenna ports used for UE data transmission more quickly compared to the need to go through a handover process. In some aspects, transmission point-to-point feedback may be enabled by configuring the UE antenna port to correspond to physical antennas at different transmission points.

  [0083] In some aspects, the UE specific reference signal enables this operation (eg, in LTE-A, Rel-10 and higher situations). CSI-RS and DM-RS are reference signals used in the LTE-A situation. Interference estimation may be performed based on CSI-RS muting or facilitated by CSI-RS muting. For the same cell ID setup, when the control channel is common to all transmission points, there may be a control capacity problem because the PDCCH capacity may be limited. The control capacity can be expanded by using the FDM control channel. Its extension, such as relay PDCCH (R-PDCCH), or enhanced PDCCH (ePDCCH) may be used to supplement, augment, or replace the PDCCH control channel.

SRS problem in CoMP scenario
[0084] In a CoMP design, one difficult part is identifying and grouping the transmission points involved in CoMP operation (for UL and / or DL CoMP sets) with minimal overhead. The SRS channel is mainly used for UL channel sounding. In CoMP, SRS is often used to identify the cell closest to the UE. Current LTE SRS channels in releases 8-10 are designed with little consideration for CoMP operation. As a result, existing CoMP designs can lead to either dimensional limitations or design complexity for various CoMP scenarios.

  [0085] Aspects of the present disclosure provide techniques that can extend a sounding reference signal (SRS) procedure for use in a multi-point coordination (CoMP) system. As described in more detail below, UEs involved in CoMP operation may be configured to send two different sets of SRS signals. For example, a first set of SRS may be targeted only for the serving cell, while a second set of SRS may be targeted for joint reception of multiple cells.

  [0086] A sounding reference signal (SRS) is transmitted by the UE on the uplink, allowing the receiving node to estimate the quality of the channel at different frequencies. In a CoMP system, SRS may allow a receiving node to determine the nearest transmission point, eg, dynamically switching transmission points serving a UE on the uplink or downlink. The techniques presented herein include periodic SRS (eg, SRS transmissions scheduled to be transmitted periodically) and non-periodic SRS (eg, a single SRS transmission triggered by a downlink transmission). ) Can be applied to both.

  [0087] SRS is used by the base station to estimate the quality of the uplink channel for a wide bandwidth outside the span assigned to a particular UE. Since the demodulation reference signal (DRS) is always associated with the physical uplink shared channel (PUSCH) and the physical uplink control channel (PUCCH) and is limited to the bandwidth allocated to the UE, this measurement is It cannot be obtained using the demodulation reference signal. Unlike the DRS associated with the physical uplink control channel and the shared channel, the SRS is not necessarily transmitted with any physical channel. If the SRS is transmitted with a physical channel, the SRS may extend over a wider frequency band. The information given by the estimate is used to schedule uplink transmissions on high quality resource blocks.

  [0088] The SRS is typically transmitted from the UE along with a cell ID (eg, serving cell PCI) that is detectable by a given transmission point. However, as described herein, the UE may transmit two sets of SRS using different cell IDs.

  [0089] A pico eNB may have its own physical cell identification (PCI) or cell ID that has an X2 connection with the macro eNB. A pico eNB has its own scheduler operation and may link with multiple macro eNBs. The RRH may or may not have the same PCI as the macro eNB and has a fiber connection with the macro eNB that provides a better backhaul. For RRH, the scheduler operation can be performed only on the macro eNB side. Femto eNBs may have limited relevance and have not been fully considered in CoMP schemes.

  [0090] The SRS techniques presented herein may be applied to several different downlink (DL) CoMP scenarios. For example, in the first scenario (scenario 1), there may be a homogeneous deployment with in-site CoMP. In the second scenario (scenario 2), there may be a homogeneous deployment with high power RRHs connected by fiber.

  [0091] In a third scenario (scenario 3), the macro eNB and RRH and / or pico eNB have different PCI. In this scenario, the common reference signal (CRS), primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH) are all transmitted from the macro eNB and pico eNB. In this scenario, cell division gain can be easily achieved by scheduling different users to different RRHs, but DL CoMP transmission based on CSI-RS or CRS requires extended feedback from the UE.

  [0092] In the fourth scenario (scenario 4), the macro eNB and the RRH have the same PCI. In some cases, only the macro eNB may send CRS, PSS, SSS, and PBCH, and in other cases, both the macro eNB and RRH may send CRS, PSS, SSS, and PBCH. For RRHs with the same cell ID, the macro eNB and RRH effectively form a “super cell” using centralized scheduling. Single frequency network (SFN) gain can be achieved, but not cell division gain. The SRS channel may be used to identify the closest RRH, and based on this, the SRS channel may perform cell division by transmitting to the UE only from those closed by the RRH.

  [0093] In scenario 3, with each RRH having a different PCI, the SRS channel from each RRH will have a different configuration, sequence, etc. For both DL CoMP and uplink (UL) CoMP, each RRH needs to try SRS sent from other RRHs. Alternatively, in scenario 4, using RRHs with the same PCI, all RRHs will attempt to decode SRS transmissions for the same UE. Depending on the received signal strength, a set of DL CoMP and UL CoMP may be formed. However, the difficulty of design is the dimension of the SRS channel, that is, more UEs may impose restrictions on the SRS channel.

  [0094] As described above, aspects of this disclosure provide techniques that may extend a sounding reference signal (SRS) procedure for use within a multi-point coordination (CoMP) system. In accordance with the techniques presented herein, UEs involved in CoMP operation may be configured to send two different sets of SRS signals. For example, a first set of SRS may be targeted only for the serving cell, while a second set of SRS may be targeted for combined reception of multiple cells.

  [0095] For example, one possible extension to scenario 3 is that one eNB (such as a macro eNB, RRH, pico eNB, or femto eNB) allocates an SRS transmission with a PCI that is different from its own. is there. This PCI may be a virtual PCI or group PCI that is signaled or exchanged between all participating nodes via fiber connections or X2 connections. All nodes that can receive this SRS may participate in DL CoMP or UL CoMP with the UE. For non-CoMP operation, all of the nodes may receive SRS belonging to its own PCI. In addition, for DL or UL CoMP operation, each node may receive SRS belonging to virtual PCI or group PCI.

  [0096] FIG. 9 shows an example of transmitting an SRS with a group PCI. In this example, the UE is served by RRH2 for non-CoMP operation. Therefore, the UE sends a first SRS with RRH2 PCI. However, the UE also sends SRS mapped to another PCI (designated group PCI) for possible CoMP operations from RRH1, RRH2, RRH3 and macro eNB.

  [0097] FIG. 10 shows another example of transmitting an SRS with group PCI. This example shows a boundary situation where the UE is served by one eNB (eNB0) but at the boundary between eNB0 and another macro eNB (eNB1). In this example, RRH2 has the same PCI as eNB0 and RRH3 has the same PCI as eNB1 (eg, as in scenario 4). In this situation, the UE may send the neighboring node's PCI (PCI1) in addition to its own PCI (PCI0). Macro eNB0 may schedule the UE to send SRS according to PCI0 as well as PCI1. The macro eNB, eNB1 and eNB0 may jointly transmit or receive to the UE.

Multiplexing different SRS using separate power control
[0098] When the UE is configured for at least two SRS configurations, different SRSs may be multiplexed according to different techniques. For example, the UE may be configured to utilize time division multiplexing (TDM) to switch between two SRS configurations. This TDM approach can be a suitable solution because it has little or no effect on the peak to average ratio. Alternatively, the UE may be configured to transmit two SRS configurations via frequency division multiplexing (FDM) with different cyclic shifts or different combs, but this approach is If the configuration is transmitted within the same subframe, it may increase the peak to average ratio.

  [0099] For a TDM SRS transmission opportunity, one SRS may target only the serving cell. Other SRS may be targeted for combined reception of multiple cells (transmission points). According to some aspects, two different power control schemes may be used for different SRS configurations.

  [00100] For example, the first power control scheme may be referred to as power control scheme A (PC_A), which may include multiple reception points (eg, four transmission points as shown in FIG. 9) or different reception points. Can be used for targeted SRS. The second power control scheme may be referred to as power control scheme B (PC_B) and may be used for SRS targeting reception points in a single cell.

  [00101] PC_A results in SRS targeting multiple cells being transmitted at a higher power offset relative to SRS targeting only the serving transmission point. PC_A may also enable outer loop power control, and potentially transmit power control (TPC) commands that are separate from PUSCH and PUCCH may be used (the transmit power for SRS is the transmit power command for PUSCH and PUCCH Does not need to be tied directly to).

  [00102] A PC_B power control scheme targeting one or more serving reception points (eg, RRH2 in the example shown in FIG. 9) may utilize a different power offset than the PC_A power control scheme. In this case, the SRS may be transmitted with a different power offset, the outer power control loop may be disabled, and / or PC_B may use a different outer loop than PC_A, using the same TPC as the PUSCH with a fixed power offset Can be done.

  [00103] The signaling impact of the extension described above is that the eNB needs to signal multiple SRS configurations to the UE. The participating nodes need to exchange information for a common SRS configuration targeted for DL CoMP or UL CoMP. There may also be additional signaling to support multiple power control levels for different SRS configurations, or alternatively, delta offsets in different SRS configurations.

  [00104] The impact on UE transmission is that the UE will have multiple SRS transmissions with different configurations (time, frequency, shift and comb) and possibly different power offsets. The impact on eNB reception is that the eNB may receive SRS having multiple configurations from the same UE, and the eNB may execute multiple power control loops for different SRS.

  [00105] In alternative embodiments, more than two SRS configurations may be used by the UE and / or eNB and RRH.

  [00106] FIG. 11 illustrates example operations 1100 performed by a user equipment (UE) in accordance with aspects of the present disclosure. Operation 1100 begins at 1102, where the UE transmits a first sounding reference signal (SRS) that is currently serving the UE and is intended for one or more base stations associated with the first cell identifier. To do. At 1104, the UE transmits a second SRS intended for combined reception by one or more base stations associated with the second cell identifier. At 1106, the UE adjusts the transmit power of the first and second SRS using separate power control schemes.

  [00107] FIG. 12 illustrates example operations 1200 performed by a base station (BS) in accordance with aspects of the present disclosure. Operation 1200 begins at 1202, where a BS is currently serving a UE and transmits a first sounding reference signal (SRS) intended for one or more base stations associated with a first cell identifier. The user equipment (UE) is configured as follows. At 1204, the BS configures the UE to transmit a second SRS directed to another or multiple base stations associated with the second cell identifier. At 1206, the BS sends one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS using separate power control schemes.

  [00108] Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any of them Can be represented by a combination.

  [00109] Further, it should be appreciated that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein can be implemented as electronic hardware, computer software, or a combination of both. The contractor will be understood. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in a variety of ways for each particular application, but such implementation decisions should not be construed as departing from the scope of the present disclosure.

  [00110] Various exemplary logic blocks, modules, and circuits described in connection with the disclosure herein are general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gates. Implementation or implementation using an array (FPGA) or other programmable logic device, individual gate or transistor logic, individual hardware components, or any combination thereof designed to perform the functions described herein it can. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may be implemented as a combination of computing devices, eg, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors associated with a DSP core, or any other such configuration. You can also.

  [00111] The method or algorithm steps described in connection with the disclosure herein may be implemented directly in hardware, implemented in software modules executed by a processor, or a combination of the two. The software module may be RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, register, hard disk, removable disk, CD-ROM, or any other form of storage known in the art. Can reside in the media. An exemplary storage medium is coupled to the processor such that the processor can read information from, and / or write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium can reside in the ASIC. The ASIC can reside in the user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal. In general, if there are operations shown in the figures, those operations may have corresponding counterpart means-plus-function components with similar numbers.

  [00112] In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and computer communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media may be RAM, ROM, EEPROM, CD-ROM, or other optical disk storage, magnetic disk storage or other magnetic storage device, or any desired form in the form of instructions or data structures. Any other medium that can be used to carry or store the program code means and that can be accessed by a general purpose or special purpose computer or a general purpose or special purpose processor can be provided. In addition, any connection is properly referred to as a computer-readable medium. For example, software sends from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, wireless, and microwave Where included, coaxial technology, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media. As used herein, a disk and a disc are a compact disc (CD), a laser disc (disc), an optical disc (disc), a digital versatile disc (disc). ) (DVD), floppy disk (registered trademark) and Blu-ray (registered trademark) disk, which normally reproduces data magnetically and ) Optically reproduces data with a laser. Combinations of the above should also be included within the scope of computer-readable media.

[00113] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to this disclosure will be readily apparent to those skilled in the art and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Accordingly, the present disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[C1]
A method for wireless communication by a user equipment (UE) comprising:
Transmitting a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier;
Transmitting a second SRS intended for the second one or more base stations associated with the second cell identifier;
Adjusting the transmit power of the first and second SRSs using separate power control schemes.
[C2]
The method of C1, wherein the UE is configured to periodically transmit at least one of the first and second SRS.
[C3]
The method of C1, wherein the UE is configured to transmit at least one of the first and second SRS aperiodically.
[C4]
Adjusting the transmit power of the first and second SRSs using separate power control schemes;
Adjusting the first SRS using a first power control scheme;
Adjusting the second SRS using a second power control scheme, wherein the first power control scheme is such that the first SRS is transmitted with a different transmission power than the first SRS. The method of C1, which results in a result.
[C5]
The method of C4, wherein the first power control scheme utilizes an outer power control loop having a transmit power control (TPC) command from a base station.
[C6]
The method of C5, wherein the second power control scheme does not utilize an outer power control loop.
[C7]
The method of C5, wherein the TPC command of the first power control scheme is different from a TPC command applied to another physical uplink channel.
[C8]
The method of C1, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.
[C9]
The method of C1, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell.
[C10]
A method for wireless communication by a first base station, comprising:
User equipment (UE) to transmit a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier. ) And
Configuring the UE to transmit a second SRS intended for a second one or more base stations associated with a second cell identifier;
Sending one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS using separate power control schemes.
[C11]
The method of C10, wherein the UE is configured to periodically transmit at least one of the first and second SRS.
[C12]
The method of C10, wherein the UE is configured to transmit at least one of the first and second SRS aperiodically.
[C13]
The method of C10, wherein the one or more TPC commands comprise a TPC command utilized within an outer power control loop of the first power control scheme.
[C14]
The method of C13, wherein the one or more TPC commands further comprises a separate TPC command utilized within an outer power control loop of the second power control scheme.
[C15]
The method of C13, further comprising transmitting a TPC command applied by the UE to adjust a transmission power of one or more other physical uplink channels.
[C16]
The method of C10, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.
[C17]
The method of C10, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell.
[C18]
An apparatus for wireless communication by a user equipment (UE),
Means for transmitting a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier;
Means for transmitting a second SRS intended for a second one or more base stations associated with a second cell identifier;
And means for adjusting the transmission power of the first and second SRS using separate power control schemes.
[C19]
The apparatus of C18, wherein the UE is configured to periodically transmit at least one of the first and second SRS.
[C20]
The apparatus of C18, wherein the UE is configured to transmit at least one of the first and second SRS aperiodically.
[C21]
Adjusting the transmit power of the first and second SRSs using separate power control schemes;
Adjusting the first SRS using a first power control scheme;
Adjusting the second SRS using a second power control scheme, wherein the first power control scheme is such that the first SRS is transmitted with a different transmission power than the first SRS. The device of C18, which results in a result.
[C22]
The apparatus of C21, wherein the first power control scheme utilizes an outer power control loop having a transmit power control (TPC) command from a base station.
[C23]
The apparatus of C22, wherein the second power control scheme does not utilize an outer power control loop.
[C24]
The apparatus according to C22, wherein the TPC command of the first power control scheme is different from a TPC command applied to another physical uplink channel.
[C25]
The apparatus of C18, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.
[C26]
The apparatus of C18, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell.
[C27]
An apparatus for wireless communication by a first base station,
User equipment (UE) to transmit a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier. Means for configuring)
Means for configuring the UE to transmit a second SRS intended for a second one or more base stations associated with a second cell identifier;
And means for sending one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS using separate power control schemes.
[C28]
The apparatus of C27, wherein the UE is configured to periodically transmit at least one of the first and second SRS.
[C29]
The apparatus of C27, wherein the UE is configured to transmit at least one of the first and second SRS aperiodically.
[C30]
The apparatus of C27, wherein the one or more TPC commands comprise a TPC command utilized within an outer power control loop of the first power control scheme.
[C31]
The apparatus of C30, wherein the one or more TPC commands further comprises a separate TPC command utilized within an outer power control loop of the second power control scheme.
[C32]
The apparatus of C30, further comprising means for transmitting a TPC command applied by the UE to adjust transmission power of one or more other physical uplink channels.
[C33]
The apparatus of C27, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.
[C34]
The apparatus of C27, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell.
[C35]
An apparatus for wireless communication by a user equipment (UE),
Transmitting a first sounding reference signal (SRS) currently served to the UE and intended for a first one or more base stations associated with a first cell identifier; Configured to transmit a second SRS directed to a second one or more base stations associated with the and to adjust the transmission power of the first and second SRS using separate power control schemes At least one processor,
And a memory coupled to the at least one processor.
[C36]
An apparatus for wireless communication by a first base station,
User equipment (UE) to transmit a first sounding reference signal (SRS) currently serving the UE and intended for the first one or more base stations associated with the first cell identifier And configuring the UE to transmit a second SRS directed to a second one or more base stations associated with a second cell identifier, using a separate power control scheme At least one processor configured to send one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS;
And a memory coupled to the at least one processor.
[C37]
A computer program product comprising a computer readable medium having instructions stored thereon, wherein the instructions are
Transmitting a first sounding reference signal (SRS) currently serving the UE and intended for the first one or more base stations associated with the first cell identifier;
Transmitting a second SRS intended for the second one or more base stations associated with the second cell identifier;
A computer program product executable by one or more processors for adjusting the transmit power of the first and second SRS using separate power control schemes.
[C38]
A computer program product comprising a computer readable medium having instructions stored thereon, wherein the instructions are
User equipment (UE) to transmit a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier. ) And
Configuring the UE to transmit a second SRS intended for a second one or more base stations associated with a second cell identifier;
Sending one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first and second SRS using separate power control schemes, or A computer program product that can be executed by multiple processors.

Claims (38)

A method for wireless communication by a user equipment (UE) comprising:
Transmitting a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier;
Transmitting a second SRS intended for the second one or more base stations associated with the second cell identifier;
Adjusting the transmission power of the first SRS and the second SRS using different power control schemes, and the different power control schemes use different outer power control loops;
A method comprising:   The method of claim 1, wherein the UE is configured to periodically transmit at least one of the first SRS and the second SRS.   The method of claim 1, wherein the UE is configured to transmit at least one of the first SRS and the second SRS aperiodically. Adjusting the transmit power of the first SRS and the second SRS using separate power control schemes;
Adjusting the first SRS using a first power control scheme;
Adjusting the second SRS using a second power control scheme, wherein the first power control scheme is such that the first SRS is transmitted with a different transmission power than the second SRS. The method of claim 1, which results in a result.   5. The method of claim 4, wherein the second power control scheme utilizes an outer power control loop having a transmit power control (TPC) command from a base station.   The method of claim 5, wherein the first power control scheme does not utilize an outer power control loop.   6. The method of claim 5, wherein the TPC command for the second power control scheme is different from TPC commands applied to other physical uplink channels.   The method of claim 1, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.   The method of claim 1, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell. A method for wireless communication by a first base station, comprising:
User equipment (UE) to transmit a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier. ) And
Configuring the UE to transmit a second SRS intended for a second one or more base stations associated with a second cell identifier;
For adjusting said transmission power of said first SRS and the second SRS using different power control scheme, and sending one or more transmission power control (TPC) command for the UE, the different The power control method uses a different outer power control loop,
A method comprising:   The method of claim 10, wherein the UE is configured to periodically transmit at least one of the first SRS and the second SRS.   The method of claim 10, wherein the UE is configured to transmit at least one of the first SRS and the second SRS aperiodically. The first SRS is adjusted using a first power control scheme, and the second SRS is adjusted using a second power control scheme;
The method of claim 10, wherein the one or more TPC commands comprise a TPC command utilized within an outer power control loop of the second power control scheme.   The method of claim 13, wherein the one or more TPC commands further comprise a separate TPC command utilized within an outer power control loop of the first power control scheme.   The method of claim 13, further comprising transmitting a TPC command applied by the UE to adjust a transmission power of one or more other physical uplink channels.   11. The method of claim 10, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.   The method of claim 10, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell. An apparatus for wireless communication by a user equipment (UE),
Means for transmitting a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier;
Means for transmitting a second SRS intended for a second one or more base stations associated with a second cell identifier;
Means for adjusting the transmission power of the first SRS and the second SRS using different power control schemes, and the different power control schemes use different outer power control loops;
An apparatus comprising:   The apparatus of claim 18, wherein the UE is configured to periodically transmit at least one of the first SRS and the second SRS.   The apparatus of claim 18, wherein the UE is configured to transmit at least one of the first SRS and the second SRS aperiodically. Adjusting the transmit power of the first and second SRSs using separate power control schemes;
Adjusting the first SRS using a first power control scheme;
Adjusting the second SRS using a second power control scheme, wherein the first power control scheme is such that the first SRS is transmitted with a different transmission power than the second SRS. The apparatus of claim 18 that results.   23. The apparatus of claim 21, wherein the second power control scheme utilizes an outer power control loop having a transmit power control (TPC) command from a base station.   23. The apparatus of claim 22, wherein the first power control scheme does not utilize an outer power control loop.   23. The apparatus of claim 22, wherein the TPC command for the second power control scheme is different from TPC commands applied to other physical uplink channels.   The apparatus of claim 18, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.   The apparatus of claim 18, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell. An apparatus for wireless communication by a first base station,
User equipment (UE) to transmit a first sounding reference signal (SRS) currently serving the UE and intended for a first one or more base stations associated with a first cell identifier. Means for configuring)
Means for configuring the UE to transmit a second SRS intended for a second one or more base stations associated with a second cell identifier;
Means for sending one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first SRS and the second SRS using different power control schemes ; Different power control schemes use different outer power control loops,
An apparatus comprising:   28. The apparatus of claim 27, wherein the UE is configured to periodically transmit at least one of the first SRS and the second SRS.   28. The apparatus of claim 27, wherein the UE is configured to transmit at least one of the first SRS and the second SRS aperiodically. The first SRS is adjusted using a first power control scheme, and the second SRS is adjusted using a second power control scheme;
28. The apparatus of claim 27, wherein the one or more TPC commands comprise a TPC command utilized within an outer power control loop of the second power control scheme.   32. The apparatus of claim 30, wherein the one or more TPC commands further comprise a separate TPC command utilized within an outer power control loop of the first power control scheme.   32. The apparatus of claim 30, further comprising means for transmitting a TPC command applied by the UE to adjust transmission power of one or more other physical uplink channels.   28. The apparatus of claim 27, wherein the second cell identifier comprises a virtual cell identifier associated with a plurality of base stations involved in multipoint coordination (CoMP) operation with the UE.   28. The apparatus of claim 27, wherein the second cell identifier comprises a cell identifier associated with a neighboring cell. An apparatus for wireless communication by a user equipment (UE),
Transmitting a first sounding reference signal (SRS) currently served to the UE and intended for a first one or more base stations associated with a first cell identifier; Transmitting a second SRS directed to a second one or more base stations associated with the and adjusting transmission power of the first SRS and the second SRS using different power control schemes The at least one processor configured as described above and the different power control schemes use different outer power control loops;
And a memory coupled to the at least one processor. An apparatus for wireless communication by a first base station,
User equipment (UE) to transmit a first sounding reference signal (SRS) currently serving the UE and intended for the first one or more base stations associated with the first cell identifier And configuring the UE to transmit a second SRS directed to a second one or more base stations associated with a second cell identifier, and using a different power control scheme at least one processor wherein sending one or more transmission power control (TPC) commands to UE, configured to to adjust the transmit power of the first SRS and the second SRS, the Different power control schemes use different outer power control loops,
And a memory coupled to the at least one processor. Transmitting a first sounding reference signal (SRS) currently serving the UE and intended for the first one or more base stations associated with the first cell identifier;
Transmitting a second SRS intended for the second one or more base stations associated with the second cell identifier;
For the adjusting the transmit power of the first SRS and the second SRS using different power control schemes, e Bei which is the instructions executable by one or more processors,
The computer program wherein the different power control schemes use different outer power control loops . Said first sounding reference signal (SRS) currently serving a user equipment (UE ) and transmitting to a first one or more base stations associated with a first cell identifier Configuring the UE ;
Configuring the UE to transmit a second SRS intended for a second one or more base stations associated with a second cell identifier;
Sending one or more transmit power control (TPC) commands to the UE to adjust the transmit power of the first SRS and the second SRS using different power control schemes; Bei give a is instructions executable by one or more processors,
The computer program wherein the different power control schemes use different outer power control loops .

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