Non-orthogonal Multiple Access Assisted Multi-Region Geocast

TL;DR

This paper introduces a location-based NOMA-assisted multi-region geocast framework that enhances spectral and energy efficiency by leveraging user geographical info for simultaneous multi-group message delivery.

Contribution

It proposes a novel spectrum sharing framework combining NOMA and multi-group multicast based on geographical data, with a new downlink beamforming design and decoding strategy.

Findings

NOMA significantly improves spectral efficiency over SDMA and OMA.

Energy efficiency gains are demonstrated with the proposed framework.

Limitations of NOMA in certain scenarios are identified.

Abstract

This work proposes a novel location-based multi-group multicast framework which is termed as non-orthogonal multiple access (NOMA) assisted multi-region geocast. This novel spectrum sharing framework exploits the NOMA technology to realize the simultaneous delivery of different messages to different user groups characterized by different geographical locations. The essence of the proposed framework is that the geographical information of user groups unites NOMA and multi-group multicast to enhance the spectral efficiency (SE) and the energy efficiency (EE) of wireless transmissions. Specifically, we investigate the downlink beamforming design of the proposed framework in multiple-input single-output (MISO) settings. The decoding strategy for NOMA is designed and guaranteed by users' geographical information and required quality of service (QoS). The majorization and minimization (MM) algorithm is exploited to solve the non-convex and intractable problems therein. Comprehensive numerical experiments are further provided to show that NOMA holds tremendous promise but also limitations in terms of SE and EE, compared with spatial division multiple access (SDMA) and orthogonal multiple access (OMA).