Asymptotic analysis of V-BLAST MIMO for coherent optical wireless communications in Gamma-Gamma turbulence

TL;DR

This paper analyzes the asymptotic bit error rate of V-BLAST MIMO systems in turbulent optical wireless channels, revealing that diversity gain equals the number of receivers and enabling higher data rates through spatial multiplexing.

Contribution

It introduces a new method to evaluate asymptotic BER in Gamma-Gamma turbulence and uncovers the counterintuitive result that diversity gain equals the number of receivers.

Findings

Diversity gain of V-BLAST MIMO equals the number of receivers.

Symbol rate per transmission can match the number of transmitters with some diversity loss.

Higher data rates are achievable in turbulent channels by exploiting spatial multiplexing.

Abstract

This paper investigates the asymptotic BER performance of coherent optical wireless communication systems in Gamma-Gamma turbulence when applying the V-BLAST MIMO scheme. A new method is proposed to quantify the performance of the system and mathematical solutions for asymptotic BER performance are derived. Counterintuitive results are shown since the diversity gain of the V-BLAST MIMO system is equal to the number of the receivers. As a consequence, it is shown that when applying the V-BLAST MIMO scheme, the symbol rate per transmission can be equal to the number of transmitters with some cost to diversity gain. This means that we can simultaneously exploit the spatial multiplexing and diversity properties of the MIMO system to achieve a higher data rate than existing schemes in a channel that displays severe turbulence and moderate attenuation.