Throughput maximization using quantized rate control in multiple antenna communication
View Patent ↗A feedback link between a receiver and a transmitter in a multiple antenna communication system is used to control the transmission rate and thereby improve system throughput performance.
1. A method for rate control in a multiple antenna communication system, the method comprising:
estimating channel conditions between a receiver and a transmitter; and
selecting one out of a plurality of optimized transmission rates for transmission using a feedback link back to the transmitter, with said selecting being performed based on the estimated channel conditions; and the plurality of transmission rates being optimized so as to maximize throughput of the system for a given average power;
wherein an optimal transmission rate is selected using the following maximization of throughput:
max
R
,
R
(
γ
)
·
R
(
γ
)
(
1
-
Prob
(
log
det
(
I
+
P
M
γ
)
<
R
(
γ
)
)
)
,
where γ is the channel state, R is the set of transmission rates, R(γ) is a mapping from the set of effective channel qualities to the set of transmission rates, I is the mutual information of the channel, P is the total available average power, and M is the number of transmit antennae.
2. The method of claim 1 wherein the channel conditions are represented in the rate allocation by an equivalent one-dimensional channel condition.
3. The method of claim 1 wherein a pre-evaluation of the multiple-antenna communication system was performed based on the frame error probability of the system.
4. The method of claim 1 , wherein an adaptive gradient search technique is utilized to efficiently find optimal rate allocation.
5. The method of claim 1 , wherein the channel conditions are estimated using preamble-based channel estimation.
6. The method of claim 1 , wherein the feedback link provides log 2 (3) or fewer bits of feedback per block.
7. A receiver implementing rate control in a multiple antenna communication system, the receiver comprising:
a channel estimator for estimating channel conditions between the receiver and a transmitter; and
a feedback link selector which selects one out of a plurality of optimized transmission rates for transmission using a feedback link back to the transmitter, with said selection being based on the estimated channel conditions; and the plurality transmission rates being optimized so as maximize throughput of the system for a given power range;
wherein an optimal transmission rate is selected using the following maximization of throughput:
max
R
,
R
(
γ
)
·
R
(
γ
)
(
1
-
Prob
(
log
det
(
I
+
P
M
γ
)
<
R
(
γ
)
)
)
,
where γ is the channel state, R is the set of transmission rates, R(γ) is a mapping from the set of effective channel qualities to the set of transmission rates, I is the mutual information of the channel, P is the total available average power, and M is the number of transmit antennae.