On the performance of multi-stage multi-user detection assisted fast-FH/MFSK

A multi-stage multi-user detection (MUD) scheme designed for a fast frequency-hopping/multilevel frequency-shift-keying (fast-FH/MFSK) system is proposed, which exploits the explicit knowledge of the hopping addresses assigned to users. The received signal level is attenuated by a constant scaling factor, when it is deem to be overwhelmed by multi-user interference. For the sake of preventing erroneous detection events, when communicating over frequency-selective fading channels, the scheme advocated invokes a variable detection threshold parameter. In the investigated scenario the achievable bit error rate (BER) of the proposed scheme was reduced by as much as an order of magnitude in comparison to that of a single-user detection (SUD) scheme when transmitting over an AWGN channel. For transmission over a channel exhibiting uncorrelated frequency-domain fading, a variable - rather than fixed threshold was used for the sake of achieving a reduced BER.