On the outage probability of a multiuser TAS/MRC system with outdated feedback

Abstract

This paper investigates the outage probability of the multiuser transmit antenna selection/maximal-ratio combining (TAS/MRC) system over Rayleigh fading channels with outdated feedback. The exact outage probability is first derived. Then the asymptotic outage probability is analyzed to gain more insights into the effect of feedback delay. The analytical results show that: 1) increasing the number of users has the same effect on the outage probability as increasing the number of transmit antennas at the base station; 2) with outdated feedback, the asymptotic diversity order of the multiuser TAS/MRC system reduces to the number of receive antennas at the users. Theoretical analysis is verified by simulation results.