System and method for multi-access MIMO channels with feedback capacity constraint
First Claim
Patent Images
1. A MIMO system comprising:
- at least one mobile unit configured to transmit a signal based on a selected power matrix and a selected beam-forming matrix; and
a base station configured to receive the signal from the at least one mobile unit, the base station comprising;
a CSIR estimator configured to receive the signal and estimate a channel matrix for the at least one mobile device; and
a CSIT generator configured to broadcast an index to the at least one mobile unit, the index corresponding to a region of a channel matrix space enclosing the estimated channel matrix of the at least one mobile unit;
wherein the selected power matrix and the selected beam-forming matrix are selected based on the index broadcast by the CSIT generator.
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Abstract
Systems and methods of MIMO wireless communication system with partial feedback are disclosed. In one embodiment, a base station estimates the channel matrices of the K mobile units and transmits an index value corresponding to each of the estimated channel matrix. Each mobile unit selects a power control matrix and beam-forming matrix based on the received index value and transmits its data stream to the base station using the selected power control and beam-forming matrix. A method for generating the sets of power control matrices, beam-forming matrices, and partitions of the channel matrix space is disclosed.
161 Citations
19 Claims
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1. A MIMO system comprising:
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at least one mobile unit configured to transmit a signal based on a selected power matrix and a selected beam-forming matrix; and
a base station configured to receive the signal from the at least one mobile unit, the base station comprising;
a CSIR estimator configured to receive the signal and estimate a channel matrix for the at least one mobile device; and
a CSIT generator configured to broadcast an index to the at least one mobile unit, the index corresponding to a region of a channel matrix space enclosing the estimated channel matrix of the at least one mobile unit;
wherein the selected power matrix and the selected beam-forming matrix are selected based on the index broadcast by the CSIT generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of optimizing the capacity of a MIMO system, the MIMO system characterized by K mobile units, each mobile unit characterized by Q levels, the K mobile units transmitting to a base station having nT antennas configured to receive a signal transmitted by the K mobile units, the method comprising:
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i. generating at least one positive, semidefinite channel matrices of size nT×
nT;
j. initializing at least one power control matrix and at least one beam-forming matrix;
k. partitioning a K×
nT×
nT channel matrix space into a set of partition regions;
l. generating at least one power control matrix and at least one beam-forming matrix based on the at least one channel matrix, the at least one power control matrix, the at least one beam-forming matrix, and the set of partition regions;
m. repeating steps c and d a preselected number, Ng, of times;
n. estimating a capacity of the at least one generated power control matrix, the at least one generated beam-forming matrix, and the set of partition regions;
o. repeating steps a through f a preselected number, Ns, of times; and
p. selecting the at least one generated power control matrix, the at least one generated beam-forming matrix, and the set of partition regions corresponding to the largest capacity. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A MIMO wireless base station comprising:
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at least one antenna configured to receive a signal from at least one mobile unit;
a receiver configured to receive the signal from the at least one antenna;
a CSIR estimator configured to estimate a channel matrix for the at least one mobile unit based in part on the signal from the at least one antenna; and
a CSIT generator configured to broadcast to the at least one mobile unit a partition index corresponding to a partition containing the channel matrix of the at least one mobile unit.
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18. A MIMO wireless mobile unit comprising:
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at least one antenna configured to transmit a signal to a base station;
a transmitter configured to transmit a signal containing an encoded data stream over the at least one antenna;
an index decoder configured to receive a partial feedback signal and extract an index associated with the mobile unit from the partial feedback signal; and
a power and beam-forming control configured to retrieve a power control matrix and beam-forming matrix from a set of pre-stored power control and beam-forming matrices based on the extracted index;
wherein the transmitter generates the transmitted signal by modifying the encoded data stream with the retrieved power control matrix and beam-forming matrix.
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19. A method for optimizing the capacity of a MIMO wireless system with partial feedback, the system characterized by K mobile units having Q levels, each mobile unit characterized by a channel matrix, the channel matrix embedded in a K×
- nR×
nT dimension channel matrix space, the method comprising;
(a) partitioning the matrix space into QK regions, {Rq};
(b) determining an optimal set of QK power control matrices, {ρ
q}, and an optimal set of QK bream-forming matrices, {Bq} based on {Rq};
(c) estimating a capacity of the MIMO system based on {Rq}, {ρ
q}, and {Bq};
repeating steps (a) through (c) a predetermined number of times; and
selecting a set of {Rq}, {ρ
q}, and {Bq} having the largest estimated capacity.
- nR×
Specification