Configuration of coordinated multipoint transmission hypotheses for channel state information reporting

Patent metadata

Field	Value
Publication number	US-9337970-B2
Application number	US-201313877799-A
Country	US
Kind code	B2
Filing date	Mar 13, 2013
Priority date	Mar 19, 2012
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A system and method for providing an eNodeB with the flexibility to configure a Channel State Information (CSI) report to match a specific Coordinated Multipoint (CoMP) transmission hypothesis, which is a candidate for a downlink transmission to a User Equipment (UE) is disclosed. A UE receives, from the eNodeB, a configuration message that specifies a CSI report. The CSI report is specified by a particular interference hypothesis and a particular desired signal hypothesis corresponding to data transmission over at least one effective channel characterized by a specific reference signal. The UE estimates interference according to the interference hypothesis, and/or estimates at least one effective channel by performing measurements on the specific reference signal, and determines a CSI report based on the interference estimation and on the estimated effective channel. The UE also transmits the CSI report to the eNodeB.

First claim

The invention claimed is:

1. A method performed at a User Equipment, UE, comprising:
receiving at least one radio resource control (RRC) configuration message from an eNodeB, wherein the at least one configuration message specifies a plurality of Channel State Information (CSI) reports each matching a different coordinated multipoint (CoMP) transmission hypothesis which is a candidate for downlink transmission to the UE, wherein each CoMP transmission hypothesis corresponds to a transmission scheme selected from a group consisting of a dynamic point blanking scheme, a dynamic point selection scheme, a coordinated beamforming scheme, and a joint transmission scheme, and wherein each of the CSI reports specifies an interference hypothesis and a desired signal hypothesis corresponding to a hypothetical data transmission over an effective channel that is characterized by a reference signal, the interference hypothesis and the desired signal hypothesis being specified, at least in part, by a Channel State Information-Interference Measurement, CSI-IM, configuration, and a Channel State Information-Reference Signal, CSI-RS configuration, respectively; and
for each of the specified CSI reports:
estimating interference according to the specified interference hypothesis, and estimating properties of the effective channel;
determining a CSI report based on the interference estimation and the estimated properties of the effective channel; and
transmitting the CSI report to the eNodeB.

2. The method of claim 1 wherein the at least one configuration message specifies a plurality of CSI processes with which the CSI reports are associated.

3. The method of claim 1 further comprising:
for each of the specified CSI reports:
determining a bitmap for the specified CSI report from the at least one configuration message, wherein each bit in the bitmap is associated with one of a plurality of reference signals, and wherein each reference signal is associated with a different effective channel;
determining, based on a value of a given bit, whether, at least parts of the hypothetical data transmission is assumed transmitted over the effective channel identified by the reference signal associated with the given bit; and
determining, for each component of the hypothetical data transmission, whether the component is assumed to have been transmitted coherently, incoherently, or on a single effective channel based on a predetermined contract or on information in the at least one configuration message.

4. The method of claim 3 further comprising:
for each of the specified CSI reports:
determining a second bitmap based on signals sent by the eNodeB, each bit in the second bitmap having a value and being associated with a corresponding one of a second plurality of reference signals, and wherein each reference signal corresponds to an effective channel; and
determining, based on the value of the bits in the second bitmap, whether to modify the interference measurement by artificially adding an interference measurement from a hypothetical transmission over the effective channel identified by the reference signal associated with the bit.

5. The method of claim 4 wherein one or both of the plurality of reference signals and a second plurality of reference signals comprise channel state information reference signals, CSI-RS, configured in a Coordinated Multi-Point, CoMP, Measurement Set.

6. The method of claim 1 further comprising configuring at least one of the specified CSI reports to reuse a rank indicator computed according to another one of the specified CSI reports.

7. The method of claim 1 further comprising configuring at least one of the specified CSI reports to reuse a per point precoder matrix indicator computed according to the plurality of CSI reports, and wherein each of the plurality of CSI reports:
corresponds to a desired signal transmitted from one of a plurality of transmission points in a joint transmission hypothesis;
is restricted to a same rank as the joint transmission hypothesis; and
corresponds to a unique signal transmission point within the plurality of transmission points associated with the joint transmission hypothesis.

8. A User Equipment, UE, comprising:
a communications interface configured to receive at least one radio resource control (RRC) configuration message from an eNodeB, wherein the at least one configuration message specifies a plurality of Channel State Information, CSI, report reports each matching a different coordinated multipoint (CoMP) transmission hypothesis which is a candidate for downlink transmission to the UE, wherein each CoMP transmission hypothesis corresponds to a transmission scheme selected from a group consisting of a dynamic point blanking scheme, a dynamic point selection scheme, a coordinated beamforming scheme, and a joint transmission scheme, and wherein each of the CSI reports specifies an interference hypothesis and a desired signal hypothesis corresponding to a hypothetical data transmission over an effective channel that is characterized by a reference signal, the interference hypothesis and the desired signal hypothesis being specified, at least in part, by a Channel State Information-Interference Measurement, CSI-IM, configuration, and a Channel State Information-Reference Signal, CSI-RS, configuration, respectively; and
a controller configured to, for each of the specified CSI reports:
estimate interference according to the specified interference hypothesis and estimate the properties of the effective channel,
determine the CSI report based on the interference estimation and the estimated properties of the effective channel; and
send the CSI report to the eNodeB.

9. The UE of claim 8 wherein the at least one configuration message specifies CSI processes with which the plurality of CSI reports are associated.

10. The UE of claim 8 wherein the controller is further configured to, for each of the specified CSI reports:
determine a bitmap for the specified CSI report from the at least one configuration message, wherein each bit in the bitmap is associated with one of a plurality of reference signals, and wherein each reference signal is associated with a different effective channel;
determine, based on a value of a given bit, whether, at least parts of the hypothetical data transmission is assumed transmitted over the effective channel identified by the reference signal associated with the given bit; and
determine, for each component of the hypothetical data transmission, whether the component is assumed to have been transmitted coherently, incoherently, or on a single effective channel based on a predetermined contract or on information in the at least one configuration message.

11. The UE of claim 8 wherein the controller is further configured to, for each of the specified CSI reports:
determine a second bitmap based on signals sent by the eNodeB, each bit in the second bitmap having a value and being associated with a corresponding one of a second plurality of reference signals, and wherein each reference signal corresponds to an effective channel; and
determine, based on the value of the bits in the second bitmap, whether to modify the interference measurement by artificially adding an interference measurement from a hypothetical transmission over the effective channel identified by the reference signal associated with the bit.

12. The UE of claim 11 wherein one or both of the plurality of reference signals and a second plurality of reference signals comprise channel state information reference signals, CSI-RS, configured in a coordinated multi-point, CoMP, Measurement Set.

13. The UE of

Assignees

• Hammarwall David
• Bergman Svante
• Jöngren George
• Ericsson Telefon Ab L M

Inventors

• Hammarwall David
• Bergman Svante
• Jöngren George

Classifications

• H04L5/0091

  Signalling for the administration of the divided path, e.g. signalling of configuration information · CPC title

• H04W24/10 Primary

  Scheduling measurement reports {; Arrangements for measurement reports} · CPC title

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04L5/0035

  Resource allocation in a cooperative multipoint environment · CPC title

• H04B17/345

  Interference values ({signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]} H04B17/336) · CPC title