A hybrid TIM-NOMA scheme for the Broadcast Channel

TL;DR

This paper proposes a hybrid TIM-NOMA scheme for K-user broadcast channels that combines interference management techniques to significantly enhance sum rates, especially at high SNR, outperforming traditional methods like TDM.

Contribution

It introduces a novel hybrid scheme combining TIM and NOMA principles, with a two-stage decoding process for improved interference management and capacity gains.

Findings

Hybrid scheme doubles sum rate compared to TDM at high SNR.

Effective management of inter-group and intra-group interference.

Significant capacity improvement demonstrated through simulations.

Abstract

Future mobile communication networks will require enhanced network efficiency and reduced system overhead. Research on Blind Interference Alignment and Topological Interference Management (TIM) has shown that optimal Degrees of Freedom can be achieved, in the absence of Channel State Information at the transmitters. Moreover, the recently emerged Non-Orthogonal Multiple Access (NOMA) scheme suggests a different multiple access approach, compared to the orthogonal methods employed in 4G, resulting in high capacity gains. Our contribution is a hybrid TIM-NOMA scheme in K-user cells, where users are divided into T groups. By superimposing users in the power domain, we introduce a two-stage decoding process, managing inter-group interference based on the TIM principles, and intra-group interference based on Successful Interference Cancellation, as proposed by NOMA. We show that the hybrid scheme can improve the sum rate by at least 100% compared to Time Division Multiple Access, for high SNR values.