2016/03/10 by Anjana A. Mahesh, Mahesh, Anjana A., B. Sundar Rajan +1
Computer Science · Engineering · #Advanced Wireless Communication Technologies #Cooperative Communication and Network Coding #FOS: Computer and information sciences #Information Theory (cs.IT) #Wireless Communication Security Techniques
paper · pdf · doi:10.48550/arxiv.1603.03152
openalex publication_date 2016/03/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Noisy index coding problems over AWGN channel are considered. For a given index coding problem and a chosen scalar linear index code of length N, we propose to transmit the N index coded bits as a single signal from a 2N- PSK constellation. By transmitting the index coded bits in this way, there is an N/2 - fold reduction in the bandwidth consumed. Also, receivers with side information satisfying certain conditions get coding gain relative to a receiver with no side information. This coding gain is due to proper utilization of their side information and hence is called "PSK side information coding gain (PSK-SICG)". A necessary and sufficient condition for a receiver to get PSK-SICG is presented. An algorithm to map the index coded bits to PSK signal set such that the PSK-SICG obtained is maximized for the receiver with maximum side information is given. We go on to show that instead of transmitting the N index coded bits as a signal from 2N- PSK, we can as well transmit them as a signal from 2N- QAM and all the results including the necessary and sufficient condition to get coding gain holds. We prove that sending the index coded bits as a QAM signal is better than sending them as a PSK signal when the receivers see an effective signal set of eight points or more.