# US 9,521,666 B2 · Method and apparatus for triggering aperiodic feedback in coordinated multipoint transmission

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- Number: US 9,521,666 B2
- Document ID: US9521666B2
- Status: Granted
- Kind: B2
- Application number: 14/573,479
- Filed: 2014-12-17
- Published: 2015-04-30
- Granted: 2016-12-13
- Earliest claimed: 2012-06-18
- Assignees: Fujitsu Limited
- Applicants: Fujitsu Limited
- Inventors: Yi Zhang; Yi Wang; Jian Zhang; Hua Zhou; Jianming Wu
- Web page: https://patentgrep.com/patent/US9521666B2

## CPC

- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
- H04B 7/0647: {Variable feedback rate}
- H04L 1/0026: {Transmission of channel quality indication}
- H04L 1/0027: {Scheduling of signalling, e.g. occurrence thereof}
- H04L 5/0035: {Resource allocation in a cooperative multipoint environment}
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals}
- H04L 5/0057: {Physical resource allocation for CQI}
- H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Embodiments of the present invention provide a method and apparatus for triggering aperiodic feedback in coordinated multipoint transmission. The method includes: transmitting, by an eNB to UE, dynamic control information (DCI) and preconfigured feedback sets corresponding to the DCI, so that the UE aperiodically feeds back corresponding channel state information (CSI) according to the DCI and the feedback sets corresponding to the DCI; wherein the preconfigured feedback sets corresponding to the DCI are classified according to a triggered transmitting point or a CSI-RS of non-zero power, or are classified according to configured CSI, or are classified according to an interference type. With the method and apparatus of the embodiments of the present invention, a relatively good tradeoff between flexibility of aperiodic CSI feedback and signaling load in a CoMP transmission process or a joint transmission process of CoMP and CA may be achieved.

## Claims

### Claim 1

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit to the UE, a 1-bit or 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling, so that the UE aperiodically feeds back corresponding channel state information according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the feedback sets corresponding to the downlink control information preconfigured via RRC signaling are classified according to configured channel state information; and
wherein the number of the feedback sets corresponding to the 1-bit downlink control information is 1, and the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 2 (depends on 1)

The eNB according to claim 1, wherein the downlink control information reuses 1 bit information or 2 bit information in a channel state information requesting domain in a format0 or format4;
when the downlink control information is 1 bit information, the feedback sets is one feedback set corresponding to downlink control information information 1; and
when the downlink control information is 2 bit information, the feedback sets are three feedback sets corresponding respectively to downlink control information 01, 10 and 11, or the feedback sets are two feedback sets corresponding respectively to downlink control information 10 and 11.

### Claim 3 (depends on 1)

The eNB according to claim 1, wherein each of the feedback sets is configured to indicate a channel state information set needing to be triggered, wherein the feedback sets are indicated via a bitmap of M bits of RRC signaling, where, M is a size of a channel state information set configured by the eNB for aperiodic feedback.

### Claim 4 (depends on 1)

The eNB according to claim 1, wherein the feedback sets are classified according to an interference type, each of the feedback sets is configured to indicate a channel state information set to which a possible interference type corresponds, wherein the feedback sets are indicated via 2(N-1) bits of RRC signaling, where, N is a size of a measurement set of coordinated multipoint transmission.

### Claim 5

A User Equipment (UE), comprising:
a receiver configured to receive 1-bit or 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling transmitted by an eNB; and
a transmitter configured to feed back aperiodically corresponding channel state information according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the feedback sets corresponding to the downlink control information preconfigured via RRC signaling are classified according to configured channel state information; and
wherein the number of the feedback sets corresponding to the 1-bit downlink control information is 1, and the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 6

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit to the UE, 1-bit or 2-bit first downlink control information and feedback sets corresponding to the first downlink control information preconfigured via Radio Resource Control (RRC) signaling, so that the UE aperiodically feeds back channel state information of corresponding Carrier Aggregation (CA) according to the first downlink control information and the feedback sets corresponding to the first downlink control information; and to transmit to the UE, 1-bit or 2-bit second downlink control information and feedback sets corresponding to the second downlink control information preconfigured via RRC signaling, so that the UE aperiodically feeds back channel state information of corresponding Coordinated Multipoint Transmission (CoMP) according to the second downlink control information and the feedback sets corresponding to the second downlink control information;
wherein the feedback sets corresponding to the second downlink control information preconfigured via RRC signaling are classified according to configured channel state information; and
wherein the number of the feedback sets corresponding to the 1-bit first downlink control information is 1, the number of the feedback sets corresponding to the 1-bit second downlink control information is 1, the number of the feedback sets corresponding to the 2-bit first downlink control information is 3 or 2, and the number of the feedback sets corresponding to the 2-bit second downlink control information is 3 or 2.

### Claim 7

A User Equipment (UE), comprising:
a receiver configured to receive 1-bit or 2-bit first downlink control information and feedback sets corresponding to the first downlink control information preconfigured via Radio Resource Control (RRC) signaling transmitted by an eNB;
a transmitter configured to feed back aperiodically channel state information of corresponding Carrier Aggregation (CA) according to the first downlink control information and the feedback sets corresponding to the first downlink control information;
wherein the receiver is further configured to receive 1-bit or 2-bit second downlink control information and preconfigured feedback sets corresponding to the second downlink control information transmitted by the eNB; and
wherein the transmitter is further configured to feed back aperiodically channel state information of corresponding Coordinated Multipoint Transmission (CoMP) according to the second downlink control information and the feedback sets corresponding to the second downlink control information;
wherein the preconfigured feedback sets corresponding to the second downlink control information are classified according to configured channel state information; and
wherein the number of the feedback sets corresponding to the 1-bit first downlink control information is 1, the number of the feedback sets corresponding to the 1-bit second downlink control information is 1, the number of the feedback sets corresponding to the 2-bit first downlink control information is 3 or 2, and the number of the feedback sets corresponding to the 2-bit second downlink control information is 3 or 2.

### Claim 8

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit to the UE, 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling, so that the UE aperiodically feeds back channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit corresponding to each piece of configured channel state information;
and wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 9

A User Equipment (UE), comprising:
a receiver configured to receive 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling transmitted by an eNB; and
a transmitter configured to feed back aperiodically channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit corresponding to each piece of configured channel state information;
and wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 10

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit to the UE, 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling, so that the UE aperiodically feeds back channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit for indicating configured carriers, and a channel state information indication bit for indicating configured channel state information corresponding to each configured carrier; and
wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 11

A User Equipment (UE), comprising:
a receiver configured to receive 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling transmitted by an eNB; and
a transmitter configured to feed back aperiodically channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit for indicating configured carriers, and a channel state information indication bit for indicating configured channel state information corresponding to each configured carrier; and
wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 12

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit to the UE, 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling, so that the UE aperiodically feeds back channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit for indicating triggered aperiodically fed back carriers, and a carrier indication bit for indicating a carrier corresponding to each piece of configured channel state information; and
wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 13

A User Equipment (UE), comprising:
a receiver configured to receive 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling transmitted by an eNB; and
a transmitter configured to feed back aperiodically channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit for indicating triggered aperiodically fed back carriers, and a carrier indication bit for indicating configured channel state information; and
wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 14

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit to the UE, 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling, so that the UE aperiodically feeds back channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit for indicating triggered carriers, and a channel state information indication bit for indicating fed back contents corresponding to all triggered carriers; and
wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 15

A User Equipment (UE), comprising:
a receiver configured to receive 2-bit downlink control information and feedback sets corresponding to the downlink control information preconfigured via Radio Resource Control (RRC) signaling transmitted by an eNB; and
a transmitter configured to feed back aperiodically channel state information of corresponding Carrier Aggregation (CA) and Coordinated Multipoint Transmission (CoMP) according to the downlink control information and the feedback sets corresponding to the downlink control information;
wherein the preconfigured feedback sets corresponding to the downlink control information are classified according to configured channel state information;
wherein the preconfigured feedback sets corresponding to the downlink control information are indicated via RRC signaling, the RRC signaling comprising a carrier indication bit for indicating triggered carriers, and a channel state information indication bit for indicating fed back contents corresponding to all triggered carriers; and
wherein the number of the feedback sets corresponding to the 2-bit downlink control information is 3 or 2.

### Claim 16

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit 1-bit downlink control information to the UE, so that the UE aperiodically feeds back corresponding channel state information according to the downlink control information and preconfigured feedback committed information corresponding to the downlink control information;
wherein the preconfigured feedback committed information corresponding to the downlink control information is feeding back first channel state information in an aperiodic feedback channel state information set.

### Claim 17

A User Equipment (UE), comprising:
a receiver configured to receive 1-bit downlink control information transmitted by an eNB; and
a transmitter configured to feed back aperiodically corresponding channel state information according to the downlink control information and preconfigured feedback committed information corresponding to the downlink control information;
wherein the preconfigured feedback committed information corresponding to the downlink control information is feeding back first channel state information in an aperiodic feedback channel state information set.

### Claim 18

An eNB, configured to trigger a User Equipment (UE) to aperiodically feed back channel state information, the eNB comprising:
a transmitter configured to transmit to the UE, 1-bit downlink control information and an anchor channel state information resource preconfigured via Radio Resource Control (RRC) signaling, so that the UE aperiodically feeds back corresponding channel state information according to the downlink control information and the anchor channel state information;
wherein the preconfigured anchor channel state information resource is at least one channel state information resource in an aperiodic feedback channel state information set; and
wherein the preconfigured anchor channel state information resource is indicated via RRC signaling, the RRC signaling comprising log2(N) bits, N bits, log2(M) bits, or M bits, for indicating the anchor channel state information resource; where N is the size of a Coordinated Multipoint Transmission (CoMP) measurement set, and M is the size of a channel state information set configured by the eNB for aperiodic feedback; wherein when the RRC signaling indicates the anchor channel state information resource via N bits or M bits, the indication is performed in a manner of a bitmap.

### Claim 19

A User Equipment (UE), comprising:
a receiver configured to receive 1-bit downlink control information and an anchor channel state Information resource preconfigured via high-layer signaling transmitted by an eNB; and
a transmitter configured to feed back aperiodically corresponding channel state information according to the downlink control information and the anchor channel state information resource;
wherein the preconfigured anchor channel state information resource is at least one channel state information resource in an aperiodic feedback channel state information set;
and wherein the preconfigured anchor channel state information resource is indicated via Radio Resource Control (RRC) signaling, the RRC signaling comprising log2(N) bits, N bits, log2(M) bits, or M bits, for indicating the anchor channel state information resource; where N is the size of a Coordinated Multipoint Transmission (CoMP) measurement set, and M is the size of a channel state information set configured by the eNB for aperiodic feedback; wherein when the RRC signaling indicates the anchor channel state information resource via N bits or M bits, the indication is performed in a manner of a bitmap.