Performance Analysis of a Generic System Model for IDMA using Serial and Parallel Interference Cancellation

In this paper the system model of a fully synchronised interleave division multiple access (IDMA) scheme without channel coding is transformed into a new but equivalent matrix model. This model allows for alternative insights into the principles of IDMA and we show that the arising matrices are highly structured and very sparse. Based on this model, the optimal detector for IDMA is derived and compared to the standard iterative receiver. We study the performance of serial and parallel interference cancellation schemes using BER analysis and EXIT charts, and show that serial interference cancellation achieve the best performance. In a last step we demonstrate that any bit interleaved DS-CDMA can be viewed as a special case of IDMA and hence an IDMA detector is applicable to multiuser DS-CDMA systems while achieving comparable performance. Index Terms IDMA, CDMA, soft interference cancellation, optimal detector, SIC, PIC.