Resource Spread Multiple Access - A Novel transmission scheme for 5G Uplink

Among the three 5G scenarios identified by ITU-R, massive MTC poses very challenging uplink design target which requires the simultaneous support of enhanced coverage, long battery life and massive connection density. During the 5G Release 14 study phase in 3GPP, the working group studied the Non-Orthogonal Multiple Access (NOMA) scheme which can improve link budget and increase user density with the cost of complex user detection scheme. Among all the candidates, Resource Spread Multiple Access (RSMA) scheme shows promising performance gain without introducing too much complexity on the receiver design. In this paper, we briefly review the RSMA scheme. For the link level performance analysis, we firstly analyze and compare the link budget among RSMA, TDMA, and FDMA to find where the gain for RSMA comes from. Meanwhile, we provide preliminary results to justify the gains compared with OMA scheme. On system design, we review the whole procedure and propose to use user centric mobility and grant free to improve the system efficiency along with NOMA.