Space-time codes with controllable ML decoding complexity for any number of transmit antennas

TL;DR

This paper introduces a flexible class of linear space-time block codes for any number of transmit antennas, allowing adjustable ML decoding complexity while maintaining high data rates and diversity, with performance close to ideal orthogonal codes.

Contribution

It presents a novel construction of space-time codes with controllable ML decoding complexity for any number of antennas, balancing performance and computational effort.

Findings

Decoding complexity can be varied from joint decoding of multiple symbols to single-symbol decoding.

Achieves high diversity levels close to optimal for various decoding complexities.

Performance near that of ideal orthogonal codes for certain decoding configurations.

Abstract

We construct a class of linear space-time block codes for any number of transmit antennas that have controllable ML decoding complexity with a maximum rate of 1 symbol per channel use. The decoding complexity for $M$ transmit antennas can be varied from ML decoding of $2^{\lceil \log_2M \rceil -1}$ symbols together to single symbol ML decoding. For ML decoding of $2^{\lceil \log_2M \rceil - n}$ ($n=1,2,...$) symbols together, a diversity of $\min(M,2^{\lceil \log_2M \rceil-n+1})$ can be achieved. Numerical results show that the performance of the constructed code when $2^{\lceil \log_2M \rceil-1}$ symbols are decoded together is quite close to the performance of ideal rate-1 orthogonal codes (that are non-existent for more than 2 transmit antennas).