Channel capacity analysis for fbmc/oqam based massive mimo systems

Abstract

One characteristics of filter bank multicarrier offset quadrature amplitude modulation (FBMC/OQAM) is that the demodulated transmitted symbols are accompanied by interference terms caused by the neighboring transmitted data in time-frequency domain. The presence of this interference is an issue for some Massive MIMO systms and until today their combination with FBMC/OQAM remains an open problem. In this thesis, a study on channel capacity of the massive multi-input multi-output (MIMO)system in the context of FBMC/OQAM and the effects of channel distortions has been carried-out. One advantage of FBMC to massive MIMO channels is self-equalization property. Due to this property, the effects of channel distortions will decrease by increasing the number of BS antennas, but,do not vanish as the base station (BS) array size increases in frequency selective channels. As a result, channel capacity cannot grow effectively by increasing the number of BS antennas. This is caused by the correlation between the multi-antenna combining tap values and the channel impulse responses between the mobile terminals and the BS antennas. To resolve this problem, a channel equalizer is introduced. This enabling us to achieve arbitrarily large SINR values by increasing the number of BS antennas and to improve channel capacity of the system. This improvement is demonstrated through matlab software with selected numerical values of the basic parameters. As simulation result shows that, signal to interference plus noise ratio (SINR)value increased by 17dB per user for Minimum Mean-Square Error (MMSE)and zero forcing(ZF), and 2dB per user for maximum ratio combiners (MRC). Similarly, the achievable rate increases by 6 bits per second per hertz for ZF and MMSE, and 1 bits per second per hertz for MRC. Also, the throughput increased by 54 megabits per second for ZF and MMSE and and 8 megabits per second for MRC. Moreover, with the channel equalizer, it is not necessary to have a flat channel response over the band of each sub-carrier in order to use single-tap equalizer.