Performance analysis of maximal-ratio combining with transmit antenna selection for generalized selection criterion

Abstract

We investigate the performance of transmit antenna selection in multi-input multi-output systems where only a single transmit antenna is selected for the transmission and multiple receive antennas are employed for maximal-ratio combining. Antenna selection is performed by a generalized selection criterion based on the ordinal number of the strength of the received signal-to-noise ratio (SNR). Starting with the statistics such as the cumulative distribution function, the probability density function, and the moment-generating function, we derive an exact closed-from expression for the performance such as the average output SNR and the average bit-error rate. By considering Nakagami fading models, we show the dependence of the performance on the fading severity. received signal-to-noise ratio (SNR) in selecting one antenna out of multiple transmit antennas is proportional to the ordinal number of the selected antenna, have been presented in terms of the bit-error rate (BER) for binary phase-sift keying (BPSK) over Rayleigh fading channels in an approximated form. As noted in (2), the exact calculation of the performance is important for the system designer to apply transmit antenna selection. However, no-closed form expressions for the perfor- mance of transmit antenna selection with a generalized selec- tion criterion over Nakagami fading channels (even Rayleigh fading channels) have been presented due to the mathematical difficulties in finding the statistics. In this paper, we present the exact closed-form expression for the performance of transmit antenna selection with a generalized selection criterion by obtaining statistics such as the cumulative distribution func- tion (CDF), the probability density function (PDF), and the moment-generating function (MGF). The channels are gen- eralized as Nakagami-m fading models with the assumption of statistically independent and identical conditions among multiple fading paths. We then verify our results by showing that our generic formulae can be further simplified for the special cases of Rayleigh fading, conventional MRC, and selection combining (SC), which are well-known results.