Bilayer Low-Density Parity-Check Codes for Decode-and-Forward in Relay Channels

This paper describes an efficient implementation of binning for decode-and-forward (DF) in relay channels using lowdensity parity-check (LDPC) codes. Bilayer LDPC codes are devised to approach the theoretically promised rate of the DF relaying strategy by incorporating relay-generated parity bits in specially designed bilayer graphical code structures. While conventional LDPC codes are sensitively tuned to operate efficiently at a certain channel parameter, the proposed bilayer LDPC codes are capable of working at two different channel parameters and two different rates: that at the relay and at the destination. To analyze the performance of bilayer LDPC codes, bilayer density evolution is devised as an extension of the standard density evolution algorithm. Based on bilayer density evolution, a design methodology is developed for the bilayer codes in which the degree distribution is iteratively improved using linear programming. Further, in order to approach to the theoretical DF rate ...

• Type: Journal
• Year: 2006
• Where: CORR
• Authors: Peyman Razaghi, Wei Yu
• Keywords: Bilayer, Bilayer Density Evolution, Bilayer Ldpc Code, CORR 2006, Education