Optimality of Separate Network-Channel Coding
The encoding and decoding of network code at network layer and channel code at the physical layer can be performed either jointly or separately. The largest achievable rate region is obtained when both are done jointly. The authors' interest in this paper lies in investigating the optimality of Separate encoding and Joint decoding of Network-Channel (NC) Code (SJNC) assuming an orthogonal access scheme. Their key result is that SJNC is optimal as it achieves the capacity region of Joint encoding and Joint decoding of NC (JJNC). However, SJNC is suboptimal if time sharing of codes is not allowed, or if separate decoding is used.