Near-optimal low-complexity decoding of space-time codes for fixed wireless applications
AssigneeAT&T Wireless Services, Inc.
InventorsTitus Lo, Vahid Tarokh
Life of this patent
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Abstract
An improved multi-antenna receiver is realized for detecting signals transmitted by a multi-antenna transmitter by summing signals received at the plurality of receiver antennas after multiplying each by a respective constant. The summed signal is applied to a maximum likelihood detector. The respective constants, λj, where j is an index designating a particular receiver antenna, are determined by evaluating the largest eigenvector of the matrix A, where Λ is a vector containing the values λj, and A is a matrix containing elements αij, which is the transfer function between the ith transmitter antenna to the jth receiver antenna. The αij terms are determined in the receiver in conventional ways.
Claims11
A data signal for use in a wireless receiver, wherein the wireless receiver forms part of a wireless system having a wireless transmitter, the data signal comprising:
- a sum signal corresponding to an addition of received signals,
- wherein each received signal is received by one of multiple receiver antennas associated with the wireless receiver,
- wherein each received signal is pre-multiplied by a selected value associated with a selected one of the multiple receiver antennas,
- wherein the received signals are transmitted by multiple transmitter antennas associated with the wireless transmitter, and
- wherein each selected pre-multiplying value is developed from one transfer function value associated with one of the multiple transmitter antennas and one of the multiple receiver antennas.
A method for processing wireless data, the method comprising:
- receiving at an m number of receiving antennas a wireless signal, wherein the wireless signal represents multiple codewords;
- and
- processing the wireless signal by way of maximum likelihood detection to determine the codewords, under a less than optimal computational process, wherein a number of computations is reduced by approximately a factor of m, at an increase in less than a factor of m in frame error probability from the optimal computational process, and wherein the optimal computational process computes all codewords for the maximum likelihood detection.
A method for wireless communication, comprising:
- transmitting encoded symbols from multiple transmitting antennas;
- each one of multiple receiving antennas receiving transmitted encoded symbols from all of the multiple transmitting antennas, wherein a particular transfer function is associated with each transmitting antenna-receiving antenna pair;
- generating multiple transfer functions using the received encoded symbols, wherein each transfer function is associated with a transmitting-receiving antenna pair associated with the received encoded symbols;
- generating multiple multiplier signals, each associated with a transfer function;
- generating multiple combined transfer function values generated from combining the transfer functions such that a number of decoding computations is reduced;
- multiplying the received encoded signals with a respective multiplier signal;
- adding the multiplied signals;
- and
- decoding the received encoded symbols, including computing a subset of a set of all possible values of the received encoded symbols, using the added signals and the combined transfer function values.
Dependencies are inferred from the claim text.