Generalized Sum-Product Algorithm for Joint Channel Decoding and Physical-Layer Network Coding in Two-Way Relay Systems

Abstract

Abstract-In this paper a physical-layer network coded twoway relay system applying Low-Density Parity-Check (LDPC) codes for error correction is considered, where two sources A and B desire to exchange information with each other by the help of a relay R. The critical process in such a system is the calculation of the network-coded transmit word at the relay on basis of the superimposed channel-coded words of the two sources. For this joint channel-decoding and network-encoding task a generalized Sum-Product Algorithm (SPA) is developed. This novel iterative decoding approach outperforms other recently proposed schemes as demonstrated by simulation results.

Joint channel decoding and physical-layer network coding in two-way QPSK relay systems by a generalized Sum-Product Algorithm

“…However, as the gains h A and h B are usually different for fading channels, the knowledge due to the four different receive signal levels should be used in the decoding process by means of a Generalized-SPA over F 4 as presented in [10] and denoted as G-SPA 4 . In this paper, we extend this scheme with respect to the transmission of QPSK signals resulting in a G-SPA over F 16 called G-SPA 16 in the sequel.…”

“…As this approach looses information, decoding based on the Arithmetic-Sum (AS-JCNC) of the source codewords was proposed for Repeat Accumulate (RA) codes in [7] and for LDPC codes in [8], [9] requiring an adapted channel decoder at the relay. As these schemes were restricted to AWGN channels with BPSK transmission, a generalization with respect to fading channels was presented in [10]. In this contribution, we extend the proposed scheme to QPSK transmission, leading to sixteen different undisturbed receive values.…”

Optimised Joint Channel Network Coding for Sensor Network with Correlated Sources

“…Then, the observations of the neighboring nodes are highly correlated. Authors studied in [1,2] the WSN with spatially correlated data which may be compressed by channel codes, and always jointly decoded at the relay [3,4]. Some other research works to considered the correlation in WSN [5][6][7].…”

Phase-level synchronization for physical-layer network coding

“…Existing works on PNC often assume the presence of phase synchronization [6]- [8]. Recently, there is also much focus on asynchronous PNC schemes [9], [10].…”