NOMA-Based D2D Communications: Towards 5G

Abstract

In this paper, a novel non-orthogonal multiple access (NOMA)-based device-to-device (D2D) communications framework is proposed. A major novelty of the proposed framework is that it introduces the new concept of "D2D group" which utilizes NOMA transmission, enabling one D2D transmitter to communicate with multiple D2D receivers simultaneously. Based on the considered framework, a resource allocation optimization problem is formulated, where multiple D2D groups are allowed to reuse the same subchannel. The objective of this work is to maximize the system sum rate by satisfying the signalto-interference-plus-noise (SINR) constraints of both D2D and traditional cellular users. Note that the formulated problem is non-deterministic polynomial-time (NP) hard in nature, thus a novel resource allocation algorithm based on the many-to-one twosided matching theory is proposed for obtaining a suboptimal solution. It is proved that the proposed algorithm converges to a stable state within limited number of iterations. Numerical results illustrate that: i) the proposed algorithm is an effective approach for obtaining near-optimal performance with acceptable complexity; and ii) the proposed NOMA-based D2D framework is capable of achieving promising gains over traditional orthogonal multiple access (OMA)-based D2D framework.

Resource Allocation for D2D Communications Underlaying a NOMA-Based Cellular Network

“…This scenario is different from that in [8], where NOMA is implemented in D2D transmissions. Furthermore, since power control is not considered for either CUs or NOMA-based D2D groups in [8], the approach in [8] cannot be directly applied to solve our problem. Our target is to maximize the sum rate of D2D pairs while guaranteeing the minimum rate requirements of CUs.…”

“…In this way, the NOMA-based cellular network can greatly increase system throughput and allow massive connectivities. Recently, several approaches have been proposed to combine the D2D communications with NOMA technology [8], [9]. The D2D users were grouped through the NOMA way in [8] to achieve better D2D rate performance, and the channel allocation problem for the NOMA-based D2D groups is modeled as a Many-to-One matching.…”

“…Recently, several approaches have been proposed to combine the D2D communications with NOMA technology [8], [9]. The D2D users were grouped through the NOMA way in [8] to achieve better D2D rate performance, and the channel allocation problem for the NOMA-based D2D groups is modeled as a Many-to-One matching. Furthermore, the D2D assisted NOMA scheme was proposed in [9] to enhance system throughput performance.…”

Resource Allocation Algorithm for NOMA-Enhanced D2D Communications with Energy Harvesting

“…e total rate of D2D users is maximized under the minimum rate requirement of cellular users. Authors in [5] analyze the rate of D2D users when NOMA technology is used to transmit information, and propose a channel allocation algorithm to maximize the total rate of the system. A NOMA-enhanced D2D communication system is considered in [6], and the subchannel and power allocation is optimized to maximize the system sum rate.…”

Multicarrier Relay Selection for Full-Duplex Relay-Assisted OFDM D2D Systems

“…Meanwhile, D2D communications can be classified in two categories, depending on whether frequency resources are shared between D2D communications and traditional cellular communications, which are termed underlay and overlay D2D communications, respectively [2]. It has been proved that underlay D2D communications would be able to provide a high spectrum efficiency and suit the spectrum sharing nature in next generation networks [5]- [7]. However, the underlay D2D transmission will break up the orthogonality between D2D communications and traditional cellular communications, and the corresponding interference shall be coordinated accordingly.…”