Adaptive OFDM system for multi-user communications over the indoor wireless optical channel

In this paper, an adaptive Orthogonal Frequency Division Multiplexing (OFDM) system is proposed for multi-user communications over indoor wireless optical channels. The designed system uses multi-user least-squares (LS) detection techniques applied to SDMA-OFDM schemes, in conjunction with angle diversity reception. The system, which does Dot present an excessive complexity, supports high bit rates for multiple users, beyond one hundred megabits per second. It also mitigates the channel fluctuations induced when either the space distribution or the number, of emitters and receivers varies. The performance of the new proposed scheme is compared with an adaptive single-user system described in previous works. The obtained results show a significant improvement with respect to previous adaptive single-user one, since the new scheme allows adaptively managing the system throughput on a multi-user environment.