Improved Iterative Detection of Multiuser Signals with Fast Frequency-Hopping Modulation

An improved iterative receiver is developed for multiuser communications using fast frequency-hopping modulation. Each user employs a channel encoder to protect its information and facilitate interference cancellation at the receiver. At the destination, in order to reliably extract signals from all users, the detection algorithm employs double iteration process: an outer iteration between the interference canceler and soft-input soft-output (SISO) decoder, and an inner iteration between the soft demapper and the SISO decoder. The proposed detection algorithm works with direct as well as relay-aided transmissions. Two relay scenarios are investigated, which are amplify-and-forward and partial-decode-and-forward relaying. Under the same spectral efficiency, simulation results demonstrate the excellent performance of the proposed receiver when compared to the performance of single iterative receiver and other previously-proposed interference cancellation schemes.