On the Capacity of SymmetricM -user Gaussian Interference Channels with Feedback

• Main Authors: Truong, Lan V, Yamamoto, Hirosuke
• Format: Journal Article
• Language: English
• Published: 27.07.2018
• Subjects: Computer Science - Information Theory; Mathematics - Information Theory
• DOI: 10.48550/arxiv.1807.10881

A general time-varying feedback coding scheme is proposed for$M$ -user fully connected symmetric Gaussian interference channels. Based on the analysis of the general coding scheme, we prove a theorem which gives a criterion for designing good time-varying feedback codes for Gaussian interference channels. The proposed scheme improves the Suh-Tse and Kramer inner bounds of the channel capacity for the cases of weak and not very strong interference when$M=2$ . This capacity improvement is more significant when the signal-to-noise ratio (SNR) is not very high. In addition, our coding scheme can be proved mathematically and numerically to outperform the Kramer code for$M\geq 2$when Signal to Noise Ratio (SNR) is equal to Interference to Noise Ratio (INR). Besides, the generalized degrees-of-freedom (GDoF) of our proposed coding scheme can be proved to be optimal in the all network situations (very weak, weak, strong, very strong) for any$M$ . The numerical results show that our coding scheme can attain better performance than the Suh-Tse coding scheme for$M=2$or the Mohajer-Tandon-Poor lattice coding scheme for$M>2$ . Furthermore, the simplicity of the encoding/decoding algorithms is another strong point of our proposed coding scheme compared with the Suh-Tse coding scheme when$M=2$and the Mohajer-Tandon-Poor lattice coding scheme when$M>2$ . More importantly, our results show that an optimal coding scheme for the symmetric Gaussian interference channels with feedback can be achieved by only using marginal posterior distributions under a better cooperation strategy between transmitters.