Spectrally-Efficient Successive Wireless Relaying Based on Network Coding

We propose a novel successive relaying scheme based on network coding (SRS), which achieves the same spectral efficiency in half-duplex multi-hop relaying channels as point-to- point transmission does. Except for the source and destination nodes, every hop in the multi-hop relaying link, two relay nodes are arranged, a transmitting relay node and a receiving relay node, and continuously switch their states in "transmitting" and "receiving" during the successive slots. Each slot, all the transmitting relay nodes simultaneously and synchronously broadcast their respective last-received packets and at the receiving relays the sum of the simultaneously received electromagnetic waves is mapped on the network coding bits of the corresponding transmitting data. Focusing on the 3-hop relay network, we analyzed the spectral efficiency of three relaying schemes. The numerical results show that SRS can improve the spectral efficiency of the 3-hop relaying network by a factor of 200% and 100% relative to the conventional hop-by-hop relaying scheme and simple physical-layer network-coding relaying scheme, respectively, in the high signal-to-noise ratio (SNR) range.