title: Statistical mechanics of broadcast channels using low-density parity-check codes.
abstract: We investigate the use of Gallager's low-density parity-check (LDPC) codes in a degraded broadcast channel, one of the fundamental models in network information theory. Combining linear codes is a standard technique in practical network communication schemes and is known to provide better performance than simple time sharing methods when algebraic codes are used. The statistical physics based analysis shows that the practical performance of the suggested method, achieved by employing the belief propagation algorithm, is superior to that of LDPC based time sharing codes while the best performance, when received transmissions are optimally decoded, is bounded by the time sharing limit.
authors.affiliation: Department of Computational Intelligence and Systems Science, Tokyo Institute of Technology, Yokohama 226-8502, Japan. knakamur@fe.dis.titech.ac.jp
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Nakamura
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kabashima
authors.forename: Robert
authors.initials: R
authors.lastname: Morelos-Zaragoza
authors.forename: David
authors.initials: D
authors.lastname: Saad