HK1228118B - Signaling for downlink coordinated multipoint in a wireless communication system - Google Patents

Description

Signaling for downlink coordinated multipoint in wireless communication systems

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 61/646,223, filed May 11, 2012, entitled “ADVANCED WIRELESS COMMUNICATION SYSTEMS AND TECHNIQUES,” the entire disclosure of which is incorporated herein by reference.

Technical Field

Embodiments of the present invention generally relate to the field of communications, and more particularly to signaling for downlink coordinated multi-point communication in a wireless communication system.

Background Art

Coordinated Multi-Point (CoMP) systems were developed to improve various operating parameters in wireless networks. There are three types of CoMP systems: Joint Transmission (JT); Dynamic Point Selection (DPS); and Coordinated Scheduling with Coordinated Beamforming (CS/CB). In JTCoMP, both a serving point (e.g., an enhanced node base station (eNB)) and a coordinating point (e.g., another eNB) can transmit the same data to a user equipment (UE). In DPS CoMP, transmission points are dynamically selected from different candidates, such as macro and pico eNBs. In CS/CB CoMP, the coordinating node can suppress interference from interfering channels. However, the eNB may not have sufficient control and signaling mechanisms for effective management of CoMP communications with the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be readily understood from the following detailed description taken in conjunction with the accompanying drawings. To facilitate this description, like reference numerals refer to like structural elements. The embodiments are illustrated in the figures of the accompanying drawings by way of example and not limitation.

FIG1 schematically illustrates a wireless communication network including a user equipment (UE) and a plurality of evolved Node Bs (eNBs) according to various embodiments.

2 is a table mapping values of a channel state information (CSI) request field to trigger aperiodic CSI feedback according to various embodiments.

FIG3 is a table mapping values of another CSI request field according to various embodiments.

FIG4 illustrates a bitmap that may be used to indicate one or more CSI processes included in a group of CSI processes for triggering aperiodic CSI feedback according to various embodiments.

5 is a flow chart illustrating a method that may be performed by a UE for triggering aperiodic CSI feedback according to various embodiments.

6 is a table mapping values of cell-specific reference signal (CRS) configuration parameters to corresponding values for a number of CRS antenna ports and CRS frequency shifts according to various embodiments.

FIG7 schematically depicts an example system in accordance with various embodiments.

DETAILED DESCRIPTION

Illustrative embodiments of the present disclosure include, but are not limited to, methods, systems, computer-readable media, and apparatus for signaling in a wireless communication network to support downlink coordinated multi-point communications.

The various aspects of the illustrative embodiments will be described using the terms typically employed by those skilled in the art to convey the essence of their work to others skilled in the art. However, alternative embodiments may be practiced using only some of the described aspects, as will be apparent to those skilled in the art. For illustrative purposes, specific numbers, materials, and configurations are set forth to provide a comprehensive understanding of the illustrative embodiments. However, alternative embodiments may be practiced without the specific details, as will be apparent to those skilled in the art. In other instances, well-known features are omitted or simplified so as not to obscure the illustrative embodiments.

Furthermore, various operations will be described as multiple discrete operations in a manner that is most helpful for understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations are necessarily order-dependent. In particular, these operations do not need to be performed in the order presented.

The phrase "in some embodiments" is used repeatedly. This phrase generally does not refer to the same embodiment; however, it may refer to the same embodiment. The terms "including," "having," and "comprising" are synonymous unless the context indicates otherwise. The phrase "A and/or B" means (A), (B), or (A and B). The phrase "A/B" means (A), (B), or (A and B), similar to the phrase "A and/or B." The phrase "at least one of A, B, and C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). The phrase "(A)B" means (B) or (A and B), i.e., A is optional.

Although specific embodiments have been illustrated and described herein, those skilled in the art will appreciate that many alternative and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the embodiments of the present disclosure. This application is intended to cover any adaptation or variation of the embodiments discussed herein. Therefore, it is expressly intended that the embodiments of the present disclosure be limited only by the claims and their equivalents.

As used herein, the term "module" may refer to, be a part of, or include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group) that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.

FIG1 schematically illustrates a wireless communication network 100 according to various embodiments. The wireless communication network 100 (hereinafter, “network 100 ”) may be an access network of a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) network, such as the Evolved Universal Terrestrial Radio Access Network (EUTRAN). The network 100 may include a base station, such as an enhanced node base station (eNB) 104, configured to wirelessly communicate with a user equipment (UE) 108.

At least initially, eNB 104 may have an established wireless connection with UE 108 and may operate as a serving node within a CoMP measurement set. One or more additional eNBs of network 100 (e.g., eNBs 112 and 116) may also be included in the CoMP measurement set. eNBs 112 and 116 may be configured to facilitate wireless communications with UE 108 by coordinating with eNB 104. The one or more additional eNBs may be collectively referred to as "coordinating nodes." An eNB may transition between coordinating and serving node roles.

The serving node and the coordinating node may communicate with each other via wireless connections and/or wired connections (eg, high-speed fiber optic backhaul connections).

These eNBs may each have substantially the same transmission power capability as one another, or alternatively, some of these eNBs may have relatively low transmission power capabilities. For example, in one embodiment, eNB 104 may be a relatively high-power base station, such as a macro eNB, while eNBs 112 and 116 may be relatively low-power base stations, such as pico eNBs and/or femto eNBs.

The eNB 104 can be configured to communicate with the UE 108 over one or more component carriers. Each component carrier can be associated with a frequency band used for communication on that component carrier. In some embodiments, individual component carriers can be considered separate cells. In some embodiments, the eNB 104 can communicate with the UE 108 over multiple component carriers (with different frequencies) using carrier aggregation. The UE 108 can receive control information on a primary serving cell and other information on a secondary serving cell. The primary and secondary serving cells can be associated with respective component carriers. Carrier aggregation can be used in addition to or instead of CoMP communication.

UE 108 may include a communication module 120 and a feedback module 124 coupled to each other. UE 108 may further include a CoMP module 128 coupled to communication module 120 and/or feedback module 124. Communication module 120 may further be coupled to one or more of a plurality of antennas 132 of UE 108 for wireless communication over network 100.

UE 108 may include any suitable number of antennas. In various embodiments, UE 108 may include at least as many antennas as the number of simultaneous spatial layers or streams received by UE 108 from the eNB, although the scope of the present disclosure may not be limited in this respect. The number of simultaneous spatial layers or streams may also be referred to as a transmission rank, or simply rank.

One or more of the antennas 132 may alternately function as transmit or receive antennas. Alternatively or additionally, one or more of the antennas 132 may be dedicated receive antennas or dedicated transmit antennas.

The eNB 104 may include a communication module 136, a CoMP management module 140, and an aperiodic feedback module 144, coupled to one another, at least as shown. The communication module 136 may further be coupled to one or more of the plurality of antennas 152 of the eNB 104. The communication module 136 may communicate (e.g., transmit and/or receive) with one or more UEs (e.g., UE 108). In various embodiments, the eNB 104 may include at least as many antennas as the number of simultaneous transmission streams transmitted to the UEs 108, although the scope of the present disclosure may not be limited in this respect. One or more of the antennas 152 may alternately function as transmit or receive antennas. Alternatively, or in addition, one or more of the antennas 152 may be dedicated receive antennas or dedicated transmit antennas.

In various embodiments, a UE 108 may be configured with one or more CSI processes for individual cells (e.g., component carriers). A CSI process may include associated CSI reference signal (CSI-RS) resources and/or associated CSI interference measurement (CSI-IM) resources. In some embodiments, the CSI-RS resources may be non-zero power (NZP) CSI-RS resources. The UE 108 may further receive a cell index and/or CSI process identifier (ID) associated with each configured CSI process (e.g., within a given cell). The one or more CSI processes may be configured for the UE 108 (e.g., by the eNB 104) using higher layer signaling (e.g., via radio resource control (RRC) signaling). The CSI processes may be used by the UE 108 to generate CSI feedback to the eNB 104 to facilitate downlink CoMP communications with the UE 108.

In various embodiments, feedback module 124 of UE 108 may receive a downlink control information (DCI) message from eNB 104 via communication module 120. The DCI message may be received, for example, on a physical downlink control channel (PDCCH). In some embodiments, the PDCCH may be an enhanced PDCCH (EPDCCH) or another type of PDCCH. The DCI message may include a CSI request field to indicate one or more CSI processes for which UE 108 is to provide CSI feedback to eNB 104. Thus, the DCI message may facilitate aperiodic reporting of CSI feedback by UE 108. In some embodiments, the CSI request field may be two bits, indicating one of four possible values. Other embodiments of the CSI request field may include other numbers of bits.

Feedback module 124 may generate CSI feedback for the indicated CSI process. The CSI feedback may include, for example, a channel quality indicator (CQI), a precoding matrix indicator (PMI), one or more selected subbands, and/or a rank indicator (RI) for the CSI process. Feedback module 124 may then transmit a CSI report including the generated CSI feedback to eNB 104 via communication module 120. The CSI report may be transmitted, for example, on a physical uplink shared channel (PUSCH).

FIG2 illustrates a table 200 that maps the values of a two-bit CSI request field according to some embodiments. As shown in table 200, the CSI request field may have a value of "01" to indicate that the feedback module 124 is to provide CSI reports for the first set of CSI processes configured for the serving cell of the UE 108. The serving cell may be a primary serving cell on which the UE 108 receives DCI including the CSI request field. In some embodiments, the UE 108 may identify the serving cell for which the UE 108 is to provide CSI feedback based on the component carrier on which the UE 108 receives the DCI.

In some embodiments, the value "01" may indicate that the UE 108 is to provide CSI feedback for all CSI processes associated with the serving cell (e.g., a first set of CSI processes may include all CSI processes associated with the serving cell). In other embodiments, the first set of CSI processes may include a subset (e.g., fewer than all) of the CSI processes associated with the serving cell. For example, the first set of CSI processes may be configured for the UE 108 via higher layers (e.g., via RRC signaling).

In various embodiments, the CSI request field may have a value of "10" to indicate that the feedback module 124 is to provide CSI reports for the second group of CSI processes. Alternatively, the CSI request field may have a value of "11" to indicate that the feedback module 124 is to provide CSI reports for the third group of CSI processes. The second and/or third groups of CSI processes may be configured by higher layers (e.g., RRC signaling), such as by the eNB 104, to indicate the CSI processes included in the second and/or third groups.

The CSI reports for the first, second, and/or third groups may be used by the eNB 104 to manage downlink CoMP communications with the UE 108. In some embodiments, in addition to CoMP communications, the CSI reports for the first, second, and/or third groups may also be used by the eNB 104 to manage carrier aggregation communications with the UE 108. The CSI request field may be similar to the CSI request field used to trigger CSI reporting to support carrier aggregation communications. However, the CSI request field used for carrier aggregation may only trigger CSI reporting for one CSI process for a particular cell or group of cells and may not allow triggering CSI reporting for more than one CSI process associated with a given cell and/or associated with different cells. Furthermore, the second and/or third groups of CSI processes may include CSI processes on different cells having the same frequency (e.g., cells having the same frequency transmitted by different eNBs).

In some embodiments, the CSI request field as described herein may be used when the UE 108 is configured with transmission mode 10 (as defined in LTE Advanced Release 11). Transmission mode 10 may support CoMP communication with the UE. In transmission mode 10, the UE 108 may provide CSI feedback for one or more CSI processes as described herein. The UE 108 may use DCI format 2D to receive scheduling information. In some embodiments, DCI format 1A may be used as a fallback mode. The UE 108 may also receive PDSCH mapping parameters for cells other than the serving cell. Additionally or alternatively, the UE 108 may use a UE-specific reference signal for demodulation of the PDSCH.

The second and/or third groups of CSI processes may include any number of one or more CSI processes. In some embodiments, the second and/or third groups may include multiple CSI processes. In some embodiments, the second and third groups may include one or more common CSI processes (e.g., one or more CSI processes included in both the second and third groups). In other embodiments, the second and third groups may each include only one CSI process. The second and/or third groups of CSI processes may include one or more CSI processes associated with a cell other than the serving cell. Additionally or alternatively, the second and/or third groups may include multiple CSI processes associated with different cells.

In various embodiments, the CSI request field may include a value of "00" to indicate that the DCI message does not trigger an aperiodic CSI report. The value "00" may be used, for example, when transmitting a DCI message to the UE 108 for another purpose other than triggering an aperiodic CSI report.

Although specific values for the two-bit CSI request field are shown in table 200, it will be apparent that these values may be mapped in any suitable manner to corresponding actions that may be different from those shown in table 200. For example, in another embodiment, a value of "00" may trigger CSI reporting for the first set of CSI processes.

As described herein, the CSI request field may be used by the eNB 104 to trigger CSI reporting for a first set of CSI processes. The eNB 104 may dynamically change the set of CSI processes for which the eNB 104 requests CSI feedback from the UE 104. The aperiodic feedback module 144 of the eNB 104 may receive the CSI report and the CoMP management module 140 may use the CSI feedback information included in the CSI report to manage downlink CoMP communications with the UE.

In other embodiments, the CSI request field may include only one bit. This bit may have a first value (e.g., "1") to trigger CSI reporting for all CSI processes of the serving cell. If the DCI message does not trigger CSI reporting, this bit may have a second value (e.g., "0"). The one-bit CSI request field may be used, for example, when the UE 108 uses a transmission mode with a common search space for PDCCH decoding (e.g., different from the UE-specific search space).

FIG3 illustrates a table 300 that maps the values of a two-bit CSI request field according to another embodiment. As shown in FIG3 , the two-bit CSI request field may include a value of "01" to indicate that the UE 108 is to provide CSI reports for a first set of CSI processes, or a value of "10" to indicate that the UE 108 is to provide CSI reports for a second set of CSI processes. The CSI request field may further include a value of "11" to indicate that the UE 108 is to provide CSI reports for both the first and second sets of processes. The CSI request field may include a value of "00" to indicate that the DCI message does not trigger an aperiodic CSI report.

2 and 3, it will be apparent that other suitable configurations of the CSI request field may be used to trigger aperiodic CSI reporting for different groups of CSI processes. For example, in another embodiment, the CSI request field may be similar to that shown in table 300, but with a value of "00" indicating that the UE 108 is to provide CSI reporting for a group of CSI processes configured for the serving cell.

In various embodiments, the CSI process groups (e.g., the first, second, and/or third groups described above) that may be triggered by the CSI request field for CSI reporting may be configured by the eNB 104 using corresponding bitmaps. These bitmaps may be transmitted by the eNB 104 to the UE 108 (e.g., via RRC signaling) to indicate which CSI processes are included in a given CSI process group. For example, FIG4 illustrates a bitmap 400 according to various embodiments. The bitmap 400 includes a plurality of bits (e.g., bits _b0 , _b1 , ..., bNK _-1 ), and individual bits may correspond to individual CSI processes to indicate whether the CSI process is included in the CSI process group defined by the bitmap 400. The bits in the bitmap 400 may be ordered according to bit index (e.g., in ascending order of cell index), and bits corresponding to CSI processes associated with the same cell index may be ordered by their corresponding CSI IDs. For example, bitmap 400 includes bits corresponding to K+1 component carriers (e.g., with cell indexes 0 to K). Each component carrier may include a maximum of N configured CSI processes. Groups of bits corresponding to CSI processes with the same cell index are arranged in ascending order of cell index in bitmap 400 (e.g., where bits ( _b0 - bN _-1 ) corresponding to the CSI process with cell index 0 are arranged before bits (bN - b2N-1) corresponding to the CSI process with _cell index ₁ in bitmap 400). Within groups of bits corresponding to CSI processes with the same cell index, the bits are sorted in ascending order of CSI process ID. For example, bit _b0 corresponds to the CSI process with cell index 0 and CSI process ID 0, bit _b1 corresponds to the CSI process with cell index 0 and CSI process ID 1, and so on.

As discussed above, the eNB 104 may transmit multiple bitmaps similar to bitmap 400 to define different CSI process groups for aperiodic CSI reporting. Aperiodic CSI reporting for individual groups may then be triggered by a DCI message including a CSI request field as described herein. In some embodiments, the bitmap used to define the CSI process groups for aperiodic CSI reporting may be transmitted as part of the CSI process configuration procedure (e.g., when the UE 108 becomes RRC-connected with the eNB 104). For example, the CoMP management module 140 of the eNB 104 may transmit the bitmap simultaneously with the CSI process configuration information (e.g., CSI-RS resources and/or CSI-IM resources) for the individual CSI processes. Additionally or alternatively, the bitmap may be transmitted separately from the CSI process configuration information to define and/or modify the CSI process groups for aperiodic CSI reporting.

In some embodiments, the CoMP management module 140 of the eNB 104 may further transmit a codebookSubsetRestriction parameter associated with an individual CSI process. The codebookSubsetRestriction parameter may be transmitted as part of the configuration of the CSI process. The codebookSubsetRestriction parameter may indicate a subset of PMIs within the codebook to be used by the UE 104 for CSI reporting for the corresponding CSI process. Alternatively or additionally, the codebookSubsetRestriction parameter may be configured for a subset of each NZP CSI-RS resource and/or subframe.

In some embodiments, the eNB 104 may configure one or more CSI dependencies between multiple configured CSI processes. For example, the eNB 104 may instruct the UE 108 to report CSI feedback for multiple CSI processes on the same rank and/or over the same preferred subband.

As discussed above, the feedback module 124 of the UE 108 can generate CSI feedback for one or more CSI processes triggered by the CSI request field. The CSI feedback can be generated based on the CSI-RS resources and/or CSI-IM resources configured for the CSI process. The CSI feedback can include, for example, the CQI, PMI, one or more selected subbands, and/or RI for the CSI process. The UE 108 can transmit the CSI feedback to the eNB 104 in a CSI report.

In some embodiments, CSI feedback for multiple CSI processes can be concatenated within the same CSI report. For example, CSI feedback for multiple CSI processes can be concatenated based on the CSI process index and/or the cell index of the CSI process. In one embodiment, CSI feedback for a group of CSI processes associated with the same component carrier (e.g., with the same cell index) can be sorted in the CSI report in ascending order of cell index. CSI feedback can be arranged within each group in ascending order of the CSI process index for each CSI process with the same cell index.

In some cases, one or more components of the CSI feedback for the first CSI process may be the same as one or more components of the CSI feedback for the second CSI process. For example, the RI reported for the first and second CSI processes may be the same. In some embodiments, the shared component (e.g., the RI in this example) may be omitted from the CSI report for either the first or second CSI process. This may reduce the bandwidth required for CSI reporting.

In some embodiments, turbo coding and/or cyclic redundancy check (CRC) coding may be used to encode the CSI report. For example, turbo coding and/or CRC coding may be used to encode the CQI and PMI reports. This may facilitate having a large payload length for the CSI report.

FIG5 is a flow chart illustrating a method 500 for triggering aperiodic CSI feedback according to various embodiments. Method 500 may be performed by a UE (e.g., UE 108). In some embodiments, the UE may include and/or have access to one or more computer-readable media having instructions stored thereon that, when executed, cause the UE to perform method 500. Additionally or alternatively, in some embodiments, the UE may include circuitry for performing method 500.

At 504, a UE may receive a first bitmap (e.g., bitmap 400) from an eNB (e.g., eNB 104) via a wireless communication network (e.g., network 100). The first bitmap may indicate one or more CSI processes included in a first group of CSI processes. For example, the first bitmap may include a plurality of bits, and each bit may correspond to an individual CSI process to indicate whether the CSI process is included in the first group of CSI processes. Each bit may have a first value (e.g., "1") to indicate that the corresponding CSI process is included in the first group, or a second value (e.g., "0") to indicate that the corresponding CSI process is not included in the first group. In some embodiments, the plurality of bits in the bitmap may be ordered according to the cell index of the CSI process (e.g., in ascending order of the cell index), and the bits corresponding to CSI processes with the same cell index may be ordered according to the CSI process ID of the CSI process (e.g., in ascending order of the CSI process ID).

At 508, the UE may receive a second bitmap from the eNB. The second bitmap may indicate one or more CSI processes included in the second group of CSI processes. The second bitmap may have a similar bit arrangement as described above for the first bitmap, but with different bits set to a first value (e.g., "1"). In some embodiments, the first and second groups may include one or more common CSI processes.

At 512, the UE may receive a DCI message from the eNB. The DCI message may include a CSI request field for requesting CSI feedback to support downlink CoMP transmissions to the UE. In some embodiments, the CSI request field may include two bits for forming one of four values. The CSI request field may have a first value indicating that the UE is to provide CSI feedback for a first set of CSI processes (e.g., configured at 504), or a second value indicating that the UE is to provide CSI feedback for a second set of CSI processes (e.g., configured at 508).

At 516, the UE may generate CSI feedback for the CSI process indicated by the CSI request field.

The UE may transmit the generated CSI feedback to the eNB at 520. The CSI feedback may be included in one or more CSI reports.

In some embodiments, the CSI request field may have a third value indicating that the UE is to provide CSI feedback for a set of CSI processes configured for the UE's serving cell. The serving cell may be identified by a carrier component on which the eNB transmits DCI including the CSI request field to the UE. The CSI process group configured for the serving cell may include all CSI processes configured for the serving cell or a subset of all CSI processes configured for the serving cell.

In some embodiments, the CSI request field may have a fourth value for indicating that the DCI message does not trigger a CSI report.

In other embodiments, the third or fourth value of the CSI request field may be used to indicate that the UE is to provide CSI feedback for both the first and second sets of CSI processes (eg, as configured at 504 and 508, respectively).

In various embodiments, a UE 108 may receive information related to a physical downlink shared channel (PDSCH) resource element mapping configuration for use by the UE 108 in receiving the PDSCH. In some embodiments, the CoMP module 128 of the UE 108 may receive an RRC message from an eNB that includes PDSCH resource element mapping parameters for multiple PDSCH mapping configurations. The PDSCH resource element mapping parameters may include, for example, the number of cell-specific reference signal (CRS) antenna ports, the CRS antenna port shift, the PDSCH start symbol, and the MPSFN subframe configuration for each PDSCH mapping configuration. In some embodiments, the PDSCH resource element mapping parameters may further include a non-zero-power CSI-RS identifier and/or a CSI process identifier associated with the PDSCH mapping configuration. The PDSCH mapping configuration may be further associated (explicitly or implicitly) with a PDSCH mapping configuration ID.

Any suitable number of PDSCH mapping configurations may be configured for the UE 108. For example, in one embodiment, four PDSCH mapping configurations may be configured for the UE 108. In some embodiments, the PDSCH mapping configurations may be universal (e.g., not associated with a specific cell). In other embodiments, the PDSCH mapping configurations may be associated with corresponding individual cells.

In some embodiments, the number of CRS antenna ports and the CRS antenna port shift may be jointly encoded within the CRS configuration parameters. For example, FIG6 illustrates table 600, which shows how values of a CRS configuration parameter are mapped to corresponding values of the number of CRS antenna ports and the CRS antenna port shift. As shown in table 600, the first value of the CRS configuration parameter (e.g., a value of 0) may indicate that the PDSCH mapping configuration has 4 antenna ports and a CRS frequency shift of 2 subframes. In some embodiments, the PDSCH mapping configuration may have a number of antenna ports of 1, 2, or 4. A PDSCH mapping configuration with 1 antenna port may have one of six CRS frequency shifts (e.g., 0, 1, 2, 3, 4, or 5 subframes), while a PDSCH mapping configuration with 2 or 4 antenna ports may have one of three CRS frequency shifts (e.g., 0, 1, or 2 subframes). Therefore, jointly encoding the number of CRS antenna ports and the CRS antenna port shift may require one less bit than encoding them separately.

In various embodiments, UE 108 may receive a DCI message from eNB 104 indicating one of multiple PDSCH mapping configurations (e.g., a first PDSCH mapping configuration) for UE 108 to use for receiving a PDSCH. For example, the DCI message may include a PDSCH mapping configuration ID corresponding to one of the PDSCH mapping configurations configured using RRC signaling as described above. In some embodiments, the PDSCH mapping configuration ID may be jointly encoded with a component carrier indicator indicating a first component carrier among multiple configured component carriers on which the PDSCH is to be transmitted to UE 108. For example, the DCI message may include a carrier aggregation cell identification field (CIF) indicating the PDSCH mapping configuration and component carrier for the UE to use for receiving the PDSCH. In some embodiments, the CIF may be three bits. The three-bit CIF may have eight different values to indicate one of two component carriers and one of four PDSCH mapping configurations. In other embodiments, the PDSCH mapping configuration ID may be included in a field separate from the CIF.

The UE 108 may use the PDSCH resource element mapping parameters to receive the PDSCH via CoMP communication. For example, the PDSCH resource element mapping parameters may facilitate avoiding CRS collisions with the PDSCH. For joint transmission (JT) CoMP, when resource element muting is used to mitigate CRS collisions with the PDSCH, the UE 108 may use the mapping parameters to determine the instantaneous rate matching mode. For dynamic point selection (DPS), the mapping parameters may be used to avoid the need for resource element muting. Additionally, for DPS in transmission modes 1, 2, 3, and 4, as proposed in LTE-Advanced Release 11, the UE 108 may use the PDSCH resource element mapping parameters to determine the specific CRS that should be used for PDSCH demodulation.

In embodiments where the PDSCH mapping configuration is associated with a corresponding individual cell (component carrier), the transmitting cell may be indicated to the UE 108 to indicate the PDSCH mapping configuration for the UE to use to receive the PDSCH. In some embodiments, the carrier aggregation CIF may be used to indicate the transmitting cell for downlink CoMP (e.g., using a CIF value not used for carrier aggregation). Other bit sizes and/or settings may be used to indicate the PDSCH mapping configuration for the UE 108 to use, as will be apparent.

The eNBs 104/112/116 and/or UEs 108 described herein can be implemented in a system using any suitable hardware and/or software to configure as desired. FIG7 illustrates, for one embodiment, an example system 700 that includes one or more processors 704, system control logic 708 coupled to at least one of the processors 704, system memory 712 coupled to the system control logic 708, non-volatile memory (NVM)/storage 716 coupled to the system control logic 708, a network interface 720 coupled to the system control logic 708, and/or an input/output (I/O) device 732 coupled to the system control logic 708.

The processor 704 may include one or more single-core or multi-core processors. The processor 704 may include any combination of general-purpose processors and special-purpose processors (eg, graphics processors, application processors, baseband processors, etc.).

System control logic 708 for one embodiment may include any suitable interface controller for providing any suitable interface to at least one of processors 704 and/or to any suitable device or component in communication with system control logic 708 .

System control logic 708 for one embodiment may include one or more memory controllers for providing an interface to system memory 712. System memory 712 may be used to load and store data and/or instructions to, for example, system 700. System memory 712 for one embodiment may include any suitable volatile memory, such as a suitable dynamic random access memory (DRAM).

NVM/storage 716 may include one or more tangible, non-transitory computer-readable media for, for example, storing data and/or instructions. NVM/storage 716 may include any suitable non-volatile memory, such as flash memory, and/or any suitable non-volatile storage device, such as one or more hard disk drives (HDDs), one or more compact disk (CD) drives, and/or one or more digital versatile disk (DVD) drives, for example.

NVM/storage 716 may include storage resources that are physically part of the device on which system 700 is installed, or that are accessible to the device but not necessarily part of the device. For example, NVM/storage 716 may be accessed over a network via network interface 720 and/or accessed through input/output (I/O) devices 732.

The network interface 720 may include a transceiver 722 for providing a radio interface for the system 700 to communicate over one or more networks and/or with any other suitable devices. The transceiver 722 may implement the communication module 120 of the UE 108 or the communication module 136 of the eNB 104. In various embodiments, the transceiver 722 may be integrated with other components of the system 700. For example, the transceiver 722 may include the processor of the processor 704, the memory of the system memory 712, and the NVM/storage of the NVM/storage 716. The network interface 720 may include any suitable hardware and/or firmware. The network interface 720 may include multiple antennas to provide a multiple-input, multiple-output radio interface. For one embodiment, the network interface 720 may include, for example, a wired network adapter (e.g., an Ethernet network adapter), a wireless network adapter, a telephone modem, and/or a wireless modem.

In one embodiment, at least one of the processors 704 may be packaged together with the logic of one or more controllers of the system control logic 708. In one embodiment, at least one of the processors 704 may be packaged together with the logic of one or more controllers of the system control logic 708 to form a system-in-package (SiP). In one embodiment, at least one of the processors 704 may be integrated on the same chip as the logic of one or more controllers of the system control logic 708. In one embodiment, at least one of the processors 704 may be integrated on the same chip as the logic of one or more controllers of the system control logic 708 to form a system-on-chip (SoC). In one embodiment, at least one of the processors 704 may be packaged together with memory of the NVM/storage 716 to form a package-on-package (PoP). For example, the memory may be coupled to an application processor and may be configured together with the application processor as a PoP.

In various embodiments, I/O device 732 may include a user interface designed to enable a user to interact with system 700, a peripheral component interface designed to enable peripheral components to interact with system 700, and/or a sensor designed to determine environmental conditions and/or location information related to system 700.

In various embodiments, the user interface may include, but is not limited to, a display (e.g., an LCD display, a touch screen display, etc.), a speaker, a microphone, one or more capturing devices (e.g., a camera and/or a video camera), a flash (e.g., an LED flash), and a keyboard.

In various embodiments, the peripheral component interface may include, but is not limited to, a non-volatile memory port, a Universal Serial Bus (USB) port, an audio jack, and a power supply interface.

In various embodiments, sensors may include, but are not limited to, gyroscope sensors, accelerometers, proximity sensors, ambient light sensors, and positioning units. The positioning unit may also be part of or interact with network interface 720 to communicate with components of a positioning network, such as global positioning system (GPS) satellites.

In various embodiments, the system 700 may be a mobile computing device such as, but not limited to, a laptop computing device, a tablet computing device, a netbook, a smartphone, etc. In various embodiments, the system 700 may have more or fewer components and/or a different architecture.

Although certain embodiments have been illustrated and described herein for purposes of illustration, numerous alternative and/or equivalent embodiments or implementations calculated to achieve the same purpose may be substituted for the embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptation or variation of the embodiments discussed herein. Therefore, it is expressly stated that the embodiments described herein are limited only by the claims and their equivalents.

Claims (35)

1. An apparatus used by a user equipment (UE), the apparatus comprising: Communication circuitry for communicating with evolved Node B (eNB) via a wireless communication network; and A feedback circuit, coupled to the communication circuit, is used for: Configuration information for multiple Channel State Information (CSI) processes is obtained from the eNB, wherein the configuration information includes a corresponding CodebookSubsetRestriction parameter associated with the respective individual CSI process of the multiple CSI processes to indicate a subset of precoded matrix indicators within the codebook to be used by the UE for CSI reporting; The UE receives a message from the eNB including a CSI request field, wherein the CSI request field indicates a subset of the CSI process, and for the subset of the CSI process, the UE generates CSI feedback: Based on the corresponding CodebookSubsetRestriction parameter, generate CSI feedback for the CSI process indicated by the CSI request field; and The CSI feedback is transmitted to the eNB. 2. The apparatus of claim 1, wherein the CSI request field has: The first value is used to indicate that the feedback circuit provides CSI feedback for the first group of CSI processes; or The second value is used to instruct the feedback circuit to provide a CSI report for the second set of CSI processes. 3. The apparatus of claim 2, wherein the message is a first message, and wherein the feedback circuitry is further configured to obtain a second message including a CSI request field having a third value, the third value being used to indicate that the second message does not trigger CSI feedback. 4. The apparatus of claim 2, wherein the first group comprises a subset of fewer than all CSI processes associated with the serving cell, configured by the configuration information. 5. The apparatus of claim 4, wherein the plurality of CSI processes include CSI processes associated with corresponding cells among the plurality of cells of the serving cell, and wherein the feedback circuitry is further configured to identify the first group of CSI processes associated with the serving cell based on receiving the message on the serving cell. 6. The apparatus of claim 1, wherein the individual CSI process is associated with CSI Reference Signal (CSI-RS) resources and CSI Interference Measurement (CSI-IM) resources. 7. The apparatus of claim 1, wherein the configuration information of the plurality of CSI processes is obtained via Radio Resource Control (RRC) signaling, and wherein the message is a Downlink Control Information (DCI) message. 8. The apparatus of claim 1, wherein the generated CSI feedback includes a channel quality indicator (CQI), a precoding matrix indicator (PMI), and one or more selected subband or rank indicators (RI). 9. The apparatus of claim 1, wherein the CSI feedback is transmitted to the eNB in a CSI report, the CSI report comprising CSI feedback of a plurality of CSI processes cascaded in ascending order by CSI process index. 10. An apparatus used by an evolved Node B (eNB) of a wireless communication network, the apparatus comprising: Coordinated Multipoint (CoMP) circuitry for managing downlink CoMP communication with user equipment (UE) via the wireless communication network; An aperiodic feedback circuit, coupled to the CoMP circuit, is used for: The configuration information for multiple Channel State Information (CSI) processes is transmitted to the UE, wherein the configuration information includes a corresponding CodebookSubsetRestriction parameter associated with the respective individual CSI process of the multiple CSI processes to indicate a subset of precoded matrix indicators within a codebook to be used by the UE for CSI reporting; The UE transmits a message including a CSI request field, wherein the CSI request field indicates a subset of the CSI process, and for the subset of the CSI process, the UE generates CSI feedback based on the corresponding CodebookSubsetRestriction parameter; and The UE receives CSI feedback for the one or more CSI processes indicated by the CSI request field. 11. The apparatus of claim 10, wherein the CSI request field has: The first value is used to instruct the UE to provide CSI feedback for the first group of CSI processes; or The second value is used to instruct the UE to provide a CSI report for the second set of CSI processes. 12. The apparatus of claim 11, wherein the message is a first message, and wherein the aperiodic feedback circuit is further configured to transmit a second message including a CSI request field having a third value to the UE, the third value being configured to indicate that the second message does not trigger CSI feedback. 13. The apparatus of claim 11, wherein the first group comprises a subset of fewer than all CSI processes associated with the serving cell, configured by the configuration information. 14. The apparatus of claim 10, wherein the plurality of CSI processes include CSI processes associated with respective cells of the plurality of cells. 15. The apparatus of claim 10, wherein the configuration information of the plurality of CSI processes is transmitted via Radio Resource Control (RRC) signaling, and wherein the message is a Downlink Control Information (DCI) message. 16. The apparatus of claim 10, wherein the generated CSI feedback includes a channel quality indicator (CQI), a precoding matrix indicator (PMI), and one or more selected subband or rank indicators (RI). 17. The apparatus of claim 10, wherein an individual CSI process is associated with CSI Reference Signal (CSI-RS) resources and CSI Interference Measurement (CSI-IM) resources. 18. An apparatus for use by a user equipment (UE) to facilitate feedback of channel state information, the apparatus comprising: Communication circuits, used for: Receive configuration information from an evolved Node B (eNB) for multiple groups of one or more CSI processes, the configuration information including a corresponding CodebookSubsetRestriction parameter associated with the respective individual CSI process to indicate a subset of precoded matrix indicators within the codebook to be used by the UE for CSI reporting; and The UE receives a message in downlink control information (DCI) format from the eNB to support Coordinated Multipoint (CoMP) communication. The message includes a value in a Channel State Information (CSI) request field to indicate one of one or more groups of CSI processes, for which the UE is to provide aperiodic CSI feedback. A feedback circuit, coupled to the communication circuit, is configured to generate the aperiodic CSI feedback for the indicated group of one or more CSI processes based on the corresponding CodebookSubsetRestriction parameter. The individual CSI process is associated with CSI Reference Signal (CSI-RS) resources and CSI Interference Measurement (CSI-IM) resources. The indicated group of one or more CSI processes is associated with a serving cell and is a subset of the total number of CSI processes of the serving cell. 19. The apparatus of claim 18, wherein the value is a two-bit value identifying the one or more CSI processes, wherein the one or more CSI processes are associated with the serving cell on which the message is received. 20. The apparatus of claim 18, wherein the value is a two-bit value identifying a group of one or more CSI processes, wherein the one or more CSI processes are associated with a serving cell different from the serving cell on which the message is received. 21. The apparatus of claim 18, wherein the communication circuitry is further configured to receive another message employing the DCI format, the other message having a CSI request field having a two-digit value indicating that no non-periodic CSI report has been triggered. 22. The apparatus of any one of claims 18-21, wherein the configuration information comprises a bitmap received from the eNB, wherein: The bitmap includes multiple groups of bits; The individual groups of these multiple groups correspond to individual configurations of the serving cells, including the serving cells; and The individual bits of the group correspond to the individual CSI process of the serving cell configured for the group. 23. The apparatus of any one of claims 18-21, wherein the aperiodic CSI feedback includes a channel quality indicator (CQI), a precoding matrix indicator (PMI), a precoding type indicator, or a rank indicator (RI). 24. The apparatus of any one of claims 18-21, wherein the user equipment is a mobile device having a touchscreen user interface. 25. A method employed by an evolved Node B (eNB) to facilitate feedback of channel state information, the method comprising: Provide the UE with configuration information for multiple groups of one or more CSI processes, the configuration information including a corresponding CodebookSubsetRestriction parameter associated with the respective individual CSI process to indicate a subset of precoded matrix indicators within the codebook to be used by the UE for CSI reporting; Generate a message with a downlink control information (DCI) format that supports coordinated multipoint (CoMP) communication, the message including a value in a channel state information (CSI) request field to indicate one of the groups of one or more CSI processes, for which the UE is to provide aperiodic CSI feedback; The message is transmitted to the user equipment (UE) via a wireless communication network; and Receive the aperiodic CSI feedback for the indicated group of one or more CSI processes; The individual CSI process is associated with CSI Reference Signal (CSI-RS) resources and CSI Interference Measurement (CSI-IM) resources; and The indicated group of one or more CSI processes is associated with a serving cell and is a subset of the total number of CSI processes of the serving cell. 26. The method of claim 25, wherein the value is a two-bit value identifying the one or more CSI processes, wherein the one or more CSI processes are associated with the serving cell on which the message is received. 27. The method of claim 25, wherein the value is a two-bit value identifying the one or more CSI processes, wherein the one or more CSI processes are associated with a serving cell different from the serving cell on which the message is received. 28. The method of claim 25, further comprising: Transmit another message in the DCI format to the UE, wherein the other message has a CSI request field with a two-digit value indicating that no non-periodic CSI report has been triggered. 29. The method of claim 25, wherein providing the configuration information includes: Generate a bitmap comprising bits from multiple groups, wherein individual groups of the multiple groups correspond to individual configurations of the serving cell, and individual bits of the groups correspond to individual CSI processes of the serving cell configuration corresponding to the group; and The bitmap is transmitted to the UE. 30. A machine-readable medium having instructions stored thereon, which, when executed, cause the machine to perform the method as claimed in any one of claims 25-29. 31. An apparatus used by an evolved Node B (eNB) to facilitate feedback of channel state information, the apparatus comprising: A component for providing configuration information to a UE for multiple groups of one or more CSI processes, the configuration information including a corresponding CodebookSubsetRestriction parameter associated with the respective individual CSI process to indicate a subset of precoded matrix indicators within a codebook to be used by the UE for CSI reporting; A component for generating a message in a downlink control information (DCI) format that supports coordinated multipoint (CoMP) communication, the message including a value in a channel state information (CSI) request field to indicate one of the groups of one or more CSI processes, for which the UE is to provide aperiodic CSI feedback; Components for transmitting the message to a user equipment (UE) via a wireless communication network; and A component for receiving the aperiodic CSI feedback for an indicated group of one or more CSI processes; The individual CSI process is associated with CSI Reference Signal (CSI-RS) resources and CSI Interference Measurement (CSI-IM) resources; and The indicated group of one or more CSI processes is associated with a serving cell and is a subset of the total number of CSI processes of the serving cell. 32. The apparatus of claim 31, wherein the value is a two-bit value identifying the one or more CSI processes, wherein the one or more CSI processes are associated with the serving cell on which the message is received. 33. The apparatus of claim 31, wherein the value is a two-bit value identifying the one or more CSI processes, wherein the one or more CSI processes are associated with a serving cell different from the serving cell on which the message is received. 34. The apparatus of claim 31, further comprising: A component for transmitting another message in the DCI format to the UE, wherein the other message has a CSI request field having a two-digit value indicating that no non-periodic CSI report has been triggered. 35. The apparatus of claim 31, wherein the component for providing the configuration information comprises: A component for generating a bitmap comprising bits of multiple groups, wherein individual groups of the multiple groups correspond to serving cells including individual configurations of the serving cell, and individual bits of the groups correspond to individual CSI processes of the serving cell configuration corresponding to the group; and A component used to transmit the bitmap to the UE.