'Institute of Electrical and Electronics Engineers (IEEE)'
Doi
Abstract
This paper deals with the problem of non-orthogonal multiple access (NOMA) in multibeam satellite systems, where the signals are jointly precoded. It is considered that the number of frames that are simultaneously transmitted is higher than the number of feeds, reducing the precoding interference mitigation capabilities as the system becomes overloaded. In order to solve this problem, we assume that the satellite user terminals are able to perform multi-user detection to mitigate the interference. In the current NOMA approach, it
is assumed a successive interference cancellation (SIC) receiver.
To increase the spectral efficiency, this paper investigates NOMA
with simultaneous non-unique detection (SND). Compared to the
case where user terminals perform single user detection (SUD),
conventional scheduling heuristic rules do not longer apply in this
scenario. Therefore, different scheduling algorithms are proposed
considering both SIC and SND strategies. As the numerical evaluations show, SND yields larger average data rates than the SIC receiver. Concerning the scheduling, the best strategy is to pair users with highly correlated channels and the lowest channel gain difference. It is also shown that the sum-rate can be increased in overloaded satellite systems with respect to satellite scenarios, where the number of transmitted frames and feeds is the same.Peer ReviewedPostprint (author's final draft
