Rotated and Scaled Alamouti Coding

TL;DR

This paper introduces a rotated and scaled version of Alamouti coding for 2x2 MIMO systems, achieving near-Golden code performance with lower decoding complexity, offering a practical alternative for reliable wireless communication.

Contribution

It proposes a novel rotated and scaled Alamouti code that improves performance and reduces decoding complexity compared to traditional repetition-based schemes.

Findings

Performance close to Golden code with slight degradation

Decoding complexity is significantly lower than Golden code

Effective for practical 2x2 MIMO systems

Abstract

Repetition-based retransmission is used in Alamouti-modulation [1998] for $2\times 2$ MIMO systems. We propose to use instead of ordinary repetition so-called "scaled repetition" together with rotation. It is shown that the rotated and scaled Alamouti code has a hard-decision performance which is only slightly worse than that of the Golden code [2005], the best known $2\times 2$ space-time code. Decoding the Golden code requires an exhaustive search over all codewords, while our rotated and scaled Alamouti code can be decoded with an acceptable complexity however.