Single-RF MIMO-OFDM system with beam switching antenna

Abstract

In this paper, we investigate the replica interference problem of a multiple input multiple output (MIMO) receiver with a beam switching antenna (BSA) within the orthogonal frequency division multiplexing (OFDM) framework. Our frequency-domain analysis has revealed the following important findings: (i) without co-existing system, replica interference in the system can be completely avoided as long as the beam pattern switching rate of the BSA receiver is an integer multiple of the product of the OFDM sampling rate and the number of receiving beam patterns and (ii) with co-existing systems, replica interference cannot always be avoided because co-existing systems may induce replicas in the operating frequency bands of the system. We present a replica interference criterion that depends on the co-existing status and users' beam switching capabilities. Based on our findings, we propose various replica interference avoidance (RINA) strategies for different co-existing and cooperating network scenarios. In addition, the overall network operation principles of the proposed RINA strategy are presented. Simulation results verify that the proposed MIMO-OFDM system with a BSA successfully provides both MIMO and OFDM benefits, thereby resolving replica interference issues.