# Interference Cancellation at the Relay for Multi-User Wireless Cooperative Networks - Computer Science > Information Theory

Abstract: We study multi-user transmission and detection schemes for a multi-accessrelay network MARN with linear constraints at all nodes. In a $J, J a, R a,M$ MARN, $J$ sources, each equipped with $J a$ antennas, communicate to one$M$-antenna destination through one $R a$-antenna relay. A new protocol calledIC-Relay-TDMA is proposed which takes two phases. During the first phase,symbols of different sources are transmitted concurrently to the relay. At therelay, interference cancellation IC techniques, previously proposed forsystems with direct transmission, are applied to decouple the information ofdifferent sources without decoding. During the second phase, symbols ofdifferent sources are forwarded to the destination in a time divisionmulti-access TDMA fashion. At the destination, the maximum-likelihood MLdecoding is performed source-by-source. The protocol of IC-Relay-TDMA requiresthe number of relay antennas no less than the number of sources, i.e., $R a\geJ$. Through outage analysis, the achievable diversity gain of the proposedscheme is shown to be $\min\{J aR a-J+1,R aM\}$. When {\small$M\leJ a\left1-\frac{J-1}{R a} ight$}, the proposed scheme achieves the maximuminterference-free int-free diversity gain $R aM$. Since concurrenttransmission is allowed during the first phase, compared to full TDMAtransmission, the proposed scheme achieves the same diversity, but with ahigher symbol rate.

Author: Liangbin Li, Yindi Jing, Hamid Jafarkhani

Source: https://arxiv.org/