High-Throughput Multi-Source Cooperation via Complex-Field Network Coding

Abstract

Physical-layer network coding over wireless networks can provide considerable throughput gains with respect to traditional cooperative relaying strategies at no loss of diversity gain. In this paper, a novel cooperation protocol is developed based on complex-field wireless network coding. Sources transmit efficiently information symbols linearly combined with symbols from other sources. Different from existing wireless network coding protocols, transmissions are not restricted to binary symbols, and do not have to be received simultaneously. In a network with sources, the developed protocol can achieve throughput up to approximately 1/ symbols per source per channel use, as well as diversity of order . To deal with decoding errors at sources, selective-and adaptive-forwarding protocols are also developed at no loss of diversity gain. Analytical results corroborated by simulated tests show considerable performance gains with respect to distributed space-time coding, and bit-level network coding protocols.

Convolutional Network-Coded Cooperation in Multi-Source Networks With a Multi-Antenna Relay

“…In [29], the CFNC has been also utilized in a network including N S sources, N R relays, and one common destination, which reaches to the full diversity order of N R + 1 along with the network throughput of 1/2 symbol per source per channel use (spspcu) (or equivalently N S /2 spcu), while the network throughput of the traditional (AF and DF) and the finite field linear network coding schemes in such a network are respectively equal to 1/(N R +1) spcu and N S /(N S + N R ) spcu. The main reason for the higher throughput of the CFNC schemes in [28] and [29] is the utilization of the complex fields instead of the finite fields, in which the symbols of different nodes, similar to the PLNC, are simultaneously transmitted and their linear combinations in the complex field are received in the other nodes; as a result, this scheme possesses highly complicated synchronization concerns of the PLNC. Furthermore, in [30], a cooperative transmission scheme based on the linear network codes designed over GF (q) has been introduced for improving the Diversity-Multiplexing Trade-off (DMT) in a network consisting of N source-destination pairs, and M intermediate relays, which reaches the full diversity order of M + 1 as well as the network throughput of N/(N + M) spcu.…”

“…Although these schemes have boosted the diversity order, but they are still suffering from low network throughput. To address this problem, [28] has introduced Complex Field Network Coding (CFNC) scheme in a network including N sources, which reaches to the diversity order of N, as well as the network throughput of approximately 1 spcu. In [29], the CFNC has been also utilized in a network including N S sources, N R relays, and one common destination, which reaches to the full diversity order of N R + 1 along with the network throughput of 1/2 symbol per source per channel use (spspcu) (or equivalently N S /2 spcu), while the network throughput of the traditional (AF and DF) and the finite field linear network coding schemes in such a network are respectively equal to 1/(N R +1) spcu and N S /(N S + N R ) spcu.…”