I am using maximum ratio combing and selection combing techniques for C-NOMA. I want to compare the results for both techniques and also suggest me any other alternative combing techniques which give better results for C-NOMA.
Maximum ratio combining is generally better than selection combining, since it directly maximizes the signal-to-noise ratio, while selection combining does not.
I'm not sure if NOMA could change anything in this respect, but I doubt that.
Non-orthogonal multiple access (NOMA), an emerging technology to improve system capacity and spectrum efficiency, has attracted significant attention. In this study, the authors propose a NOMA-based downlink cooperative cellular system, where the base station communicates with two paired mobile users simultaneously through the help of a half-duplex amplify-and-forward relay. The outage performance of the system is investigated and closed-form expressions for their respective exact and asymptotic outage scheme are derived. Furthermore, they study the ergodic sum rate of the two paired users and the upper bound of the ergodic sum rate is obtained. By comparing the NOMA with conventional multiple access (MA) via numerical simulations, they have shown that NOMA can obtain the same diversity order with conventional MA, and achieve nearly the same sum rate with conventional MA. Furthermore, NOMA can offer better spectral efficiency and user fairness since more users are served at the same time, frequency, and spreading code.
Maximum ratio combining is generally better than selection combining, since it directly maximizes the signal-to-noise ratio, while selection combining does not.
I'm not sure if NOMA could change anything in this respect, but I doubt that.
You can use successive interference cancellation SIC to separate the Noma signals. This technique is also used for Noma signal detection.
For details of the method please follow the link: Article Non-orthogonal Multiple Access (NOMA) with Successive Interf...
Best wishes
Please read the book by
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Hello! MRC could increase the interference. If your aim is to obtain diversity, you could employ other techniques like signal space diversity. SCMA that is a NOMA technique uses it.
Dear Thaherbasha Shaik ,
Particularly, for the single transmission scheme, a successive interference cancellation (SIC) is utilized to decode the received signal, sent by the relay, at the destination. On the other hand, for the enhanced superposition coded signal transmission scheme, a maximum ratio combining (MRC) is utilized at the destination to improve the ergodic sum-rate (SR)..
I would recommend to look at (cooperative) rate-splitting instead. This works much better than (cooperative) NOMA. See for instance Article Cooperative Rate-Splitting for MISO Broadcast Channel with U...
As Emil Björnson stated, MRC has generally better performance than SC. This is also valid for NOMA. Thus, MRC is considered in NOMA( Article Cooperative Non-Orthogonal Multiple Access in 5G Systems
)Moreover, if we look into C-NOMA case further. The link between users is interference free due to the SIC at the near user while the link between the source and the far user has interference due to the superimposed symbols. Thus, SC always selects the link between users. However, in this case, the performance of C-NOMA will be limited by the SIC operation at the near user and if the perfect SIC cannot be succeeded, an error propogation from near user to far user occurs. This exists even if in MRC ( Article On the Error Performance of Cooperative-NOMA with Statistical CSIT
). Hence, the incremental (selective) relaying is considered in C-NOMA to achieve the full diversity order (Article Threshold-based Selective Cooperative-NOMA
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