Joint Physical Layer Coding and Network Coding for Bidirectional Relaying Academic Article uri icon


  • We consider a communication system where two transmitters wish to exchange information through a central relay. The transmitter and relay nodes exchange data over synchronized, average power constrained additive white Gaussian noise channels with a real input with signal-to-noise ratio (SNR) of ssr. An upper bound on the capacity is 1/2 log (1+ ssr) bits per transmitter per use of the multiple access phase and broadcast phase of the bidirectional relay channel. We show that, using lattice codes and lattice decoding, we can obtain a rate of 1/2 log (1/2 + ssr) bits per transmitter, which is essentially optimal at high SNR. The main idea is to decode the sum of the codewords modulo a lattice at the relay followed by a broadcast phase which performs SlepianWolf coding. We also show that if the two transmitters use identical lattices with minimum angle decoding, we can achieve the same rate of 1/2 log(1/2 + snr). The proposed scheme can be thought of as a joint physical-layer network-layer code which outperforms other recently proposed analog network coding schemes. 2006 IEEE.

published proceedings


author list (cited authors)

  • Wilson, M. P., Narayanan, K., Pfister, H. D., & Sprintson, A.

citation count

  • 326

complete list of authors

  • Wilson, Makesh Pravin||Narayanan, Krishna||Pfister, Henry D||Sprintson, Alex

publication date

  • November 2010