Performance Comparison of Overloaded MIMO System with and without Antenna Selection

This paper investigates the performance of an overloaded multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with and without antenna selection. In the overloaded MIMO-OFDM system, even if only a small amount of feedback is available, performance can be improved by selecting the transmit antennas. Thus, this paper compares the performance of an overloaded MIMO system with and without antenna selection under different code rates. It is shown that the performance of the MIMO-OFDM system for six signal streams with QPSK modulation is about 2.0 dB better than that for three signal streams with 16QAMmodulation while it is about 5.0 dB better than that of the MIMO-OFDM system for two signal streams with 64QAMmodulation at a bit error rate (BER) of 10−3. However, it is also shown that the performance of the overloaded MIMO system is worse if the code rate of the repetition code increases. key words: overloaded MIMO, antenna selection, maximum likelihood detection