Error Exponents for Asymmetric Two-User Discrete Memoryless Source-Channel Systems

Abstract

Abstract-Consider transmitting two discrete memoryless correlated sources, consisting of a common and a private source, over a discrete memoryless multi-terminal channel with two transmitters and two receivers. At the transmitter side, the common source is observed by both encoders but the private source can only be accessed by one encoder. At the receiver side, both decoders need to reconstruct the common source, but only one decoder needs to reconstruct the private source. We hence refer to this system by the asymmetric 2-user source-channel system. In this work, we derive a universally achievable joint source-channel coding (JSCC) error exponent pair for the 2-user system by using a technique which generalizes Csiszár's method [3] for the pointto-point (single-user) discrete memoryless source-channel system. We next investigate the largest convergence rate of asymptotic exponential decay of the system (overall) probability of erroneous transmission, i.e., the system JSCC error exponent. We obtain lower and upper bounds for the exponent. As a consequence, we establish the JSCC theorem with single letter characterization.

Cognitive Interference Channels with Confidential Messages

“…We note that the cognitive interference channel (without secrecy constraints) was studied in [12,Theorem 5], where an achievable rate region (inner bound on the capacity region) is given. An achievable error exponent for this channel was studied in [13]. In this paper, we provide an outer bound on the capacity region that matches the inner bound given in [12,Theorem 5] and hence establish the capacity region for this channel.…”

“…We note that another achievable region for the cognitive interference channel (without secrecy constraints) was reported in [13], which is included within the larger achievable region in [12,Theorem 5].…”