Method and system for CQI/PMI feedback for precoded MIMO systems utilizing differential codebooks
Aspects of a method and system for CQI/PMI feedback for precoded MIMO systems utilizing differential codebooks may include generating one or more feedback messages for one or more Channel Quality Indicator (CQI) reporting units based on at least channel state information associated with the one or more CQI reporting units. One or more differential feedback messages may be generated for one or more Pre-coding Matrix Index (PMI) reporting units based on at least channel state information associated with the one or more PMI reporting units, wherein the one or more PMI reporting units span a useable bandwidth. A bandwidth and a feedback period may be assigned to each of the one or more CQI reporting units and the one or more PMI reporting units to define the one or more CQI reporting units and the one or more PMI reporting units.
1. A method for processing communication signals, the method comprising:
generating, using a circuit, one or more feedback messages for transmission over one or more Channel Quality Indicator (CQI) reporting units based on at least channel state information associated with said one or more CQI reporting units;
generating one or more differential feedback messages for transmission over one or more Pre-coding Matrix Index (PMI) reporting units based on at least channel state information associated with said one or more PMI reporting units, wherein said one or more PMI reporting units span a useable bandwidth; and
adjusting a size, in time or frequency, of said one or more CQI reporting units or said one or more PMI reporting units based on a delay spread, doppler spread, or angular spread.
2. The method according to claim 1 , comprising defining said one or more CQI reporting units and said one or more PMI reporting units by assigning a bandwidth and a feedback period to each of said one or more CQI reporting units and said one or more PMI reporting units.
3. The method according to claim 2 , comprising assigning said bandwidth and/or said feedback period to each of said one or more CQI reporting units based on said channel state information associated with said one or more CQI reporting units.
4. The method according to claim 2 , comprising assigning said bandwidth and/or said feedback period as a function of a feedback rate.
5. The method according to claim 1 , wherein said adjusting further comprises:
adjusting said size of said one or more CQI reporting units or said one or more PMI reporting units dynamically and/or adaptively.
6. The method according to claim 1 , comprising generating said channel state information associated with said one or more CQI reporting units by averaging channel measurements.
7. The method according to claim 1 , comprising generating said channel state information associated with said one or more CQI reporting units by an arbitrary function of at least channel measurements.
8. The method according to claim 1 , wherein said one or more feedback messages for transmission over said one or more CQI reporting units comprise modulation and coding levels.
9. The method according to claim 1 , wherein said one or more feedback messages for transmission over said one or more CQI reporting units comprise Signal-to-Noise-and-Interference Ratios (SINR).
10. The method according to claim 1 , wherein said one or more differential feedback messages for transmission over said one or more PMI reporting units comprise a differential pre-coding matrix.
11. The method according to claim 1 , wherein said one or more differential feedback messages for transmission over said one or more PMI reporting units comprise an index q associated with a differential pre-coding matrix V q (n), which allows constructing a pre-coding matrix V(n) according to the following difference relation:
V ( n )= V ( n− 1)+ V q ( n )
where V(n) is a pre-coding matrix associated with instance n, V(n−1) is a pre-coding matrix associated with instance n−1, and V q (n) is a differential pre-coding matrix associated with instance.
12. A system for processing communication signals, the system comprising:
one or more circuits, which enable:
generation of one or more feedback messages for transmission over one or more Channel Quality Indicator (CQI) reporting units based on at least channel state information associated with said one or more CQI reporting units;
generation of one or more differential feedback messages for transmission over one or more Pre-coding Matrix Index (PMI) reporting units based on at least channel state information associated with said one or more PMI reporting units, wherein said one or more PMI reporting units span a useable bandwidth; and
adjustment of a size, in time or frequency, of said one or more CQI reporting units or said one or more PMI reporting units based on a delay spread, doppler spread, or angular spread.
13. The system according to claim 12 , wherein said one or more circuits define said one or more CQI reporting units and said one or more PMI reporting units by assigning a bandwidth and a feedback period to each of said one or more CQI reporting units and said one or more PMI reporting units.
14. The system according to claim 13 , wherein said one or more circuits assign said bandwidth and/or said feedback period to each of said one or more CQI reporting units based on said channel state information associated with said one or more CQI reporting units.
15. The system according to claim 13 , wherein said one or more circuits assign said bandwidth and/or said feedback period as a function of a feedback rate.
16. The system according to claim 12 , wherein said one or more circuits adjust said size of said one or more CQI reporting units or said one or more PMI reporting units dynamically and/or adaptively.
17. The system according to claim 12 , wherein said one or more circuits generate said channel state information associated with said one or more CQI reporting units by averaging channel measurements.
18. The system according to claim 12 , wherein said one or more circuits generate said channel state information associated with said one or more CQI reporting units by an arbitrary function of at least channel measurements.
19. The system according to claim 12 , wherein said one or more feedback messages for transmission over said one or more CQI reporting units comprise modulation and coding levels.
20. The system according to claim 12 , wherein said one or more feedback messages for transmission over said one or more CQI reporting units comprise Signal-to-Noise-and-Interference Ratios (SINR).
21. The system according to claim 12 , wherein said one or more differential feedback messages for transmission over said one or more PMI reporting units comprise a differential pre-coding matrix.
22. The system according to claim 1 , wherein said one or more differential feedback messages for transmission over said one or more PMI reporting units comprise an index q associated with a differential pre-coding matrix V q (n), which allows constructing a pre-coding matrix V(n) according to the following difference relation:
V ( n )= V ( n− 1)+ V q ( n )
where V(n) is a pre-coding matrix associated with instance n, V(n−1) is a pre-coding matrix associated with instance n−1, and V q (n) is a differential pre-coding matrix associated with instance.
23. A method comprising:
generating, using a circuit, one or more feedback messages for transmission over one or more Channel Quality Indicator (CQI) reporting units based on at least channel state information associated with said one or more CQI reporting units;
generating one or more differential feedback messages for transmission over one or more Pre-coding Matrix Index (PMI) reporting units based on at least channel state information associated with said one or more PMI reporting units, wherein said one or more PMI reporting units span a useable bandwidth; and
dynamically adjusting a bandwidth of said one or more CQI reporting units or said one or more PMI reporting units based on a delay spread related to a distribution of multipath components.