Iterative Demodulation and Decoding of Uplink Multiuser M-ary FSK Using OFDMA Mapping

In this paper, we study iterative demodulation and decoding (IDD) for a multiuser system where users employ M-ary frequency shift keying to transmit their signals to a base station (BS). Since joint multiuser detection requires a prohibitively high computational complexity, we propose a suboptimal low-complexity detection method that can take into account extrinsic bit information, which is well-suited to IDD. Under a certain condition, its complexity grows linearly with the number of users.