QoS-Constraints and Pilot-Contamination in the Uplink of Non-cooperative Cellular Massive-MIMO

Abstract

This paper investigates the statistical-queueing con-straints and pilot contamination phenomenon in random or ir-regular cellular massive multiple-input-multiple-output (MIMO) system where base stations are Poisson distributed. Specifically, analytical expressions for the asymptotic signal-to-interference-ratio (SIR) coverage, rate-coverage and effective capacity under quality of service (QoS) statistical-exponent constraint are pro-vided for uplink transmission when each base station deploys a large number of antennas. We show that the QoS constrained capacity is in proportional to the path-loss exponent and inversely proportional to the pilot reusing probability which in turn is a function of cell load. Our simulation results prove that, pilot reuse impairments can be alleviated by employing a cellular frequency-reuse scheme. For example, with unity frequency reuse factor, we see that, 40% of the total users have SIR above −10.5dB , whereas, with frequency reuse factor of Ω = 7, the same fraction of users has SIR above 20.5dB. However, this can reduce the effective bandwidth of overall system, e.g., for 15% level, the rate drop is almost 10Mbps due to using reuse factor of Ω = 7.