Employing the Distribution of Interference to Improve Graph-Based Receiver
Abdullah A. Saed
Progress in Signals and Telecommunication Engineering, Vol. 2, No. 1, 2013.
DOI: 
Link: http://www.dline.info/pste/fulltext/v1n1/3.pdf
Abstract:
In this paper, we investigate the influence of utilizing the distribution of multi-antenna interference (MAI) on the graph-based soft iterative receiver (GSIR) instead of applying the Gaussian approximation. It is shown Gaussian approximation is not only inaccurate at high signal-to-noise (SNR) ratio but also at low SNR with the availability of a priori information (during iterations). Consequently, it severely limits performance. It is demonstrated that implementing the distribution of interference at the data detection is able to double the bandwidth efficiency and improve the power efficiency dramatically. Even if the computational power is limited and a specific bandwidth efficiency is aimed, employing the distribution of interference can still achieve few dB gain with saving around 75 percentage of the available computational power compared to Gaussian approximation. Besides, a hybrid receiver that combines between employing the distribution of interference and applying the Gaussian approximation on interference is proposed. This combination is adjustable in the way that offers a real flexibility between performance and complexity. The performance characteristics of these kind of receivers are investigated via an Exit chart analysis. Additionally, Monte-Carlo simulation results showed that at BER = 10 âˆ’ 3 the hybrid receiver needs only 1.9 dB to reach the performance of employing the distribution of interference with saving about 99.2 percentage of its computational power. The proposed method is applicable with any kind of GSIR with arbitrary modulation and channel coding schemes.