Turbo DFD with implementation in coded synchronous code-division multiple-access systems
Gang Li · Journal of Chongqing University of Posts and Telecommunications · 2004
Turbo principle is a broadlyused technique in CDMA systems because of its effectiveness in handling redundant information gleamed from other coded bits. In this paper this principle is implemented in synchronous CDMA channels with multiuser detection technique. First an MMSEbased decisionfeedback parallel interference canceller is proposed, and then after approximating its probability distribution as Gaussian, soft output is calculated and relevant information is put into a succeeding channel decoder. Channel decoder calculates each symbol's LLR as well as corresponding channel bit estimation, using the BCJR algorithm. Output is then fed back into the MUD detector. The whole process is iterated and simulation results see a closer singleuser performance with this method.