Resource allocation in device-to-device communication underlaid cellular network using SCMA: An opportunistic approach

Device-to-Device (D2D) communication underlaid cellular network has been proven to enable a significant performance improvement in future fifth generation (5G) wireless networks. Recently, sparse code multiple access (SCMA) has been proposed as an efficient multiple access method to support massive connectivity and diverse applications. In this paper, we incorporate SCMA into D2D communication underlaid cellular network, targeting at enhancing overall network performance. In order to fully exploit the potential of SCMA, we consider that SCMA codebooks can be reused by cellular uplinks and D2D links. However, if not properly handled, the resulting mutual interference may greatly degrade the performance of the hybrid system. To tackle the problem, we have proposed an Opportunistic SCMA Codebook Allocation (OSCA) strategy, aiming to maximize the sum rate of the hybrid system. Specifically, the idea of opportunistic scheduling has been applied in OSCA to implement codebook allocation for cellular user and D2D user. We show via simulation results that the proposed strategy could yield performance enhancement over the conventional strategies in terms of system spectral efficiency.