Throughput enhancement for multi-hop decode-and-forward protocol using interference cancellation with hardware imperfection

Abstract

In this paper, we propose three interference cancellation based multi-hop decode-and-forward (DF) relaying protocols to enhance end-to-end system throughput under constraint of half-duplex and hardware imperfection. In the first proposed protocol, the successive interference cancellation technique is used at each hop to send N signals from a source to a destination. Hence, the first proposed protocol can increase N times of the data rate, as compared with the corresponding conventional multi-hop DF relaying protocol in which only one source data is hop-by-hop relayed to the destination via M intermediate hops. In the second one, the source and relays can at the same time transmit their signals, and the interference cancellation can be performed to remove co-channel interference components. Therefore, the data rate of the second proposed protocol can increase M/2 times, as compared with the corresponding conventional protocol. The third proposed protocol is an efficient combination of the first and second proposed ones, and hence its data rate is higher N times than the second proposed one. Moreover, the imperfect co-channel interference cancellation is also considered in the second and third protocols. For performance evaluation, we derive exact closed-form expressions of the end-to-end throughput for three proposed protocols over Nakagami-m fading channel. We also perform simulations to verify the analytical formulas, and propose an simple transmit power allocation strategy to mitigate impact of the co-channel interference and imperfect co-channel interference cancellation.