Adaptive error protection low-density parity-check codes for joint source-channel coding schemes
Bane V. Vasic, Aleksandra M. Cvetkovic, S. Sankaranarayanan, Michael W. Marcellin · 2003
Abstruct: We propose a class of unequal error protection (UEP) low-density parity check (LDPC) codes based on cyclic difference families. The proposed code structures enable efficient adaptation of bit protection levels and are suitable for joint sourcechannel coding. I. INTRODUCTtON We consider a joint source-channel coding scheme in which a source signal is compressed by a variable length code, and then protected by an UEP channel code so that the bit error protection level depends on the content of the compressed data. Since the bit “importance distribution” varies from source codeword to source codeword, an adaptability of the channel code UEP profile is required. In this paper we propose to facilitate the UEP and adaptive error protection by using low-density parity check (LDPC) codes. We introduce a class of UEP codes with orthogonal parity checks. Such codes have been studied by Kilgus et al. [3], Mandelbaum [2] Chen, Fan and Jin [4] and Shiozaki [5], among others. Our scheme is based on irregular LDPC codes obtained from orbits of cyclic difference families (CDF).