In this paper we investigate a multi-source LDPC scheme for a Gaussian relaysystem, where M sources communicate with the destination under the help of asingle relay (M-1-1 system). Since various distributed LDPC schemes in thecooperative single-source system, e.g. bilayer LDPC and bilayer multi-edge typeLDPC (BMET-LDPC), have been designed to approach the Shannon limit, theseschemes can be applied to the $M-1-1$ system by the relay serving each sourcein a round-robin fashion. However, such a direct application is not optimal dueto the lack of potential joint processing gain. In this paper, we propose anetwork coded multi-edge type LDPC (NCMET-LDPC) scheme for the multi-sourcescenario. Through an EXIT analysis, we conclude that the NCMET-LDPC schemeachieves higher extrinsic mutual information, relative to a separateapplication of BMET-LDPC to each source. Our new NCMET-LDPC scheme thusachieves a higher threshold relative to existing schemes.
展开▼
