Design and Performance Analysis of Beam-Space MIMO System for Multi-carrier Transmission

Abstract

Beam-space multiple-input and multiple-output (BS-MIMO) system is proved to be able to support MIMO transmission using a single active antenna, which is different from the conventional MIMO system. The conventional MIMO system has to use multiple RF chains to transmit multiple streams. Due to this benefit characteristic, there is no correlation and coupling problem. Also, the hardware complexity of the system is drastically reduced in comparison with the conventional MIMO system. Eventually, it is possible to miniaturize the antenna size. However, there are very few researches on the orthogonal frequency division multiplexing (OFDM) transmission based on this BS-MIMO system. Therefore, we propose the OFDM transmission based on BS-MIMO system and analyze performance of the proposed system. The proposed system has little bit degradation of BER performance in comparison with single carrier based BS-MIMO system. When a power of transmitted OFDM signal is low, the detection error about the direction of the beam pattern at the receiver occurs. In this paper, we improve BER performance of BS-MIMO system by setting thresholds on the transmission power of OFDM signal. As a result, the proposed system with clipping scheme still generates about 2 dB BER performance degradation. However, we can confirm the practical implementation feasibility of OFDM transmission system based on the BS-MIMO system.