Research Article
A Novel Combining Method for NOMA and OMA in Cell-Free Massive MIMO System
@INPROCEEDINGS{10.1007/978-3-030-93398-2_70, author={Qiuyi Sui and Shaochuan Wu and Haoran Zhang}, title={A Novel Combining Method for NOMA and OMA in Cell-Free Massive MIMO System}, proceedings={Wireless and Satellite Systems. 12th EAI International Conference, WiSATS 2021, Virtual Event, China, July 31 -- August 2, 2021, Proceedings}, proceedings_a={WISATS}, year={2022}, month={1}, keywords={Cell free massive MIMO NOMA OMA Successive interference cancellation}, doi={10.1007/978-3-030-93398-2_70} }- Qiuyi Sui
Shaochuan Wu
Haoran Zhang
Year: 2022
A Novel Combining Method for NOMA and OMA in Cell-Free Massive MIMO System
WISATS
Springer
DOI: 10.1007/978-3-030-93398-2_70
Abstract
Cell-Free massive MIMO (cf-mMIMO) is an incarnation of distributed massive MIMO, which provides high spectral efficieny (SE). However, when the number of users increases, the SE of cf-mMIMO will decrease. In order to increase the SE when the number of users is large, many researchers investigated cf-mMIMO with non-orthogonal multiple access (NOMA). In the existing research, cf-mMIMO with NOMA requires the number of users in each cluster to be equal, which is inflexible. This paper investigates the multiple access technology for cf-mMIMO. A more flexible scheme which uses the orthogonal multiple access (OMA) and NOMA at the same time is proposed in this paper. This scheme does not require the number of users in each cluster to be equal and it combines the advantages of both NOMA and OMA. An achievable SE of this scheme is derived. It is proved that under certain number of users and the length of the channel’s coherence time conditions, using OMA and NOMA at the same time in the cf-mMIMO is able to obtain higher SE than using OMA or NOMA alone.
