Radio communications device and system, radio communications method and machine readable medium
An electronic device, and a method and computer readable medium, for use of subsets of coordinated multi-point (CoMP) transmission cells. The device includes processing circuitry configured to select a plurality of transmission cells as the subset of the CoMP set of transmission cells used to support wireless communications with a user equipment (UE). The processing circuitry selects the plurality of transmission cells based on a message from the UE that includes aggregate channel quality information (CQI) for at least two communication channels between the UE and corresponding transmission cells of the plurality of transmission cells.
1. An electronic device comprising:
processing circuitry including a processor and a memory coupled to the processor, the processing circuitry configured to:
select a plurality of transmission cells as a subset of a coordinated multi-point (CoMP) set of transmission cells used to support wireless communications with a user equipment (UE), wherein
the processing circuitry selects the plurality of transmission cells based on a message from the UE that includes aggregate channel quality information (CQI) for at least two communication channels between the UE and corresponding transmission cells of the plurality of transmission cells, the aggregate CQI being determined as a function of at least (1) a precoding matrix between the UE and a transmission cell, (2) a channel matrix between the UE and the transmission cell, (3) a system noise, and (4) interference from other transmission cells,
rank transmission cells in a cooperating set in descending order of channel quality and select a first n transmission cells to be included in the subset, and
determine channel quality according to
CQI
i
=
CQI
(
∑
j
=
1
P
h
j
H
w
j
I
+
N
)
wherein CQI i represents a channel quality indicator in a cooperating scenario i, i represents a cooperating scenario index among a plurality of cooperating scenarios, j represents an index of a transmission cell for a respective cooperating scenario, P represents a number of transmission cells in the cooperating scenario, w j represents a precoding matrix for communication between the UE and the transmission cell j, h j represents a channel matrix between the UE and the transmission cell j, I represents interference from other transmission cells than the cooperating set, N represents system noise, CQI(•) represents a channel quality indicator corresponding to a signal to interference plus noise ratio (SINR), ∥•∥ represents calculation of a norm, and • H represents a conjugated transposition.
2. The electronic device of claim 1 , wherein
the message is a feedback message that includes a precoded message indicator (PMI) and the aggregate CQI.
3. The electronic device of claim 2 , wherein
the feedback message includes PMI fields and CQI fields for respective base stations associated with the plurality of transmission cells.
4. The electronic device of claim 3 , wherein
the feedback message includes the PMI fields interleaved with the CQI fields.
5. The electronic device of claim 1 , wherein
the aggregate CQI includes respective signal to noise ratios for the plurality of transmission cells.
6. The electronic device of claim 5 , wherein
noise in the respective signal to noise ratio includes channel noise and/or interference.
7. The electronic device of claim 1 , wherein
the processing circuitry is configured to
rank transmission cells into a cooperating set in descending order of power to the UE in a per-cell mode, and
determine the subset of CoMP set of transmission cells from N cooperating scenarios, where a first n transmission cells cooperate to provide joint transmission to the UE, where n is a positive integer and N is a number of transmission cells in a cooperating set.
8. The electronic device of claim 7 , wherein
the processing circuitry includes in the subset of CoMP set of transmission cells only transmission cells having an increment in CQI at or above a predetermined channel quality difference threshold as compared with that for a first transmission cell, and a decrement in CQI below the predetermined channel quality difference as compared with that for the first transmission cell.
9. The electronic device of claim 8 , wherein
the predetermined channel quality difference threshold is determined based on a performance characteristic of the UE and/or a network spectrum utilization ratio.
10. The electronic device of claim 1 , wherein
the processing circuitry is configured to rank transmission cells based on a channel quality indicator for respective CQI components of the aggregate CQI.
11. The electronic device of claim 1 , wherein
the processing circuitry selects the first n transmission cells to be included in the subset by comparing respective channel qualities to a predetermined threshold.
12. A method comprising:
selecting with processing circuitry a plurality of transmission cells as a subset of a coordinated multi-point (CoMP) set of transmission cells used to support wireless communications with a user equipment (UE), wherein
the selecting includes selecting the plurality of transmission cells based on a message from the UE that includes aggregate channel quality information (CQI) for at least two communication channels between the UE and corresponding transmission cells of the plurality of transmission cells, the aggregate CQI being determined as a function of at least (1) a precoding matrix between the UE and a transmission cell, (2) a channel matrix between the UE and the transmission cell, (3) a system noise, and (4) interference from other transmission cells;
ranking transmission cells, by the processing circuitry, in a cooperating set in descending order of channel quality and select a first n transmission cells to be included in the subset; and
determining, by the processing circuitry, channel quality according to
CQI
i
=
CQI
(
∑
j
=
1
P
h
j
H
w
j
I
+
N
)
wherein CQI i represents a channel quality indicator in a cooperating scenario i, i represents a cooperating scenario index among a plurality of cooperating scenarios, j represents an index of a transmission cell for a respective cooperating scenario, P represents a number of transmission cells in the cooperating scenario, w j represents a precoding matrix for communication between the UE and the transmission cell j, h j represents a channel matrix between the UE and the transmission cell j, I represents interference from other transmission cells than the cooperating set, N represents system noise, CQI(•) represents a channel quality indicator corresponding to a signal to interference plus noise ratio (SINR), ∥•∥ represents calculation of a norm, and • H represents a conjugated transposition.
13. The method of claim 12 , wherein
the message is a feedback message that includes a precoded message indicator (PMI) and the aggregate CQI.
14. The method of claim 13 , wherein
the feedback message includes PMI fields and CQI fields for respective base stations associated with the plurality of transmission cells.
15. The method of claim 14 , wherein
the feedback message includes the PMI fields interleaved with the CQI fields.
16. The method of claim 12 , wherein
the aggregate CQI includes respective signal to noise ratios for the plurality of transmission cells.
17. The method of claim 16 , wherein
noise in the respective signal to noise ratio includes channel noise and/or interference.
18. A non-transitory computer readable storage device having computer readable instructions stored therein that when executed by processing circuitry perform a method, the method comprising:
selecting with the processing circuitry a plurality of transmission cells as a subset of a coordinated multi-point (CoMP) set of transmission cells used to support wireless communications with a user equipment (UE), wherein
the selecting includes selecting the plurality of transmission cells based on a message from the UE that includes aggregate channel quality information (CQI) for at least two communication channels between the UE and corresponding transmission cells of the plurality of transmission cells, the aggregate CQI being determined as a function of at least (1) a precoding matrix between the UE and a transmission cell, (2) a channel matrix between the UE and the transmission cell, (3) a system noise, and (4) interference from other transmission cells;
ranking transmission cells, by the processing circuitry, in a cooperating set in descending order of channel quality and select a first n transmission cells to be included in the subset; and
determining, by the processing circuitry, channel quality according to
CQI
i
=
CQI
(
∑
j
=
1
P
h
j
H
w
j
I
+
N
)
wherein CQI i represents a channel quality indicator in a cooperating scenario i, i represents a cooperating scenario index among a plurality of cooperating scenarios, j represents an index of a transmission cell for a respective cooperating scenario, P represents a number of transmission cells in the cooperating scenario, w j represents a precoding matrix for communication between the UE and the transmission cell j, h j represents a channel matrix between the UE and the transmission cell j, I represents interference from other transmission cells than the cooperating set, N represents system noise, CQI(•) represents a channel quality indicator corresponding to a signal to interference plus noise ratio (SINR), ∥•∥ represents calculation of a norm, and • H represents a conjugated transposition.