Performance of Remote Radio Unit Selection in Millimeter-Wave Distributed Antenna Systems Over Fluctuating Two-Ray Fading

Millimeter wave (mmWave) is a promising future wireless communication technology. To overcome the high path loss in mmWave band, distributed antenna systems (DASs) with each base station (BS) connecting to multiple remote radio units (RRUs) is a candidate solution. To better characterize the small-scale fading of mmWave channels, the fluctuating two-ray (FTR) was recently proposed. In this letter, we study the performance of RRU selection in mmWave DASs over the FTR fading. First, simplified closed-form expressions are, respectively, provided for the probability density function (PDF) and cumulative distribution function (CDF) of signal-to-noise ratio (SNR). Then, we derive the exact closed-form expressions and their high-SNR approximations for the outage probability and ergodic rate, respectively. The effect of RRU number and FTR-fading parameters on the performance are further revealed from these high-SNR approximations. Simulations validate our analytical results.