Joint Relay Selection and Resource Allocation for Relay-Assisted D2D Underlay Communications

Relay-assisted D2D (Device-to-device) communication as a supplement to direct D2D communications for enhancing LTE-A system capacity has been proposed. In this paper, a joint mode selection, relay selection and resource allocation optimization in relay-assisted D2D communications is addressed. We aim at maximizing the overall system throughput while guaranteeing the power limitations and signal-to-noise-and-interference ratios (SINR) requirements of all cellular and active D2D links. After decomposing the original design problem into two sub-problems: 1) Optimal Power Allocation (OPA); 2) Joint Mode selection, Relay selection and Channel allocation (JMRC), we then propose the corresponding algorithms to solve them sequentially. Simulation results show that our proposed scheme significantly outperforms the existing schemes

Joint Power and Channel Allocation for Relay-Assisted Device- to- Device Communications

Relay-assisted D2D (Device-to-Device) communication was proposed as a supplement to direct D2D communications for enhancing traffic offloading capacity in Long Term Evolution-Advanced (LTE-A) systems. In this paper, we formulate the joint power and channel allocation relay-assisted D2D communications problem aiming at maximizing the system sum rate of all cellular and D2D links while guaranteeing the minimum required SINR (Signal to Interference and Noise Ratio) of both links. As it is a MINLP (Mixed Integer Non-linear Programming), which can not be solved in polynomial time, we propose two heuristic algorithm (named Proposed HA1 and Proposed HA2) with different complexity levels to solve our design problems. Monte-Carlo simulation results show that the performances of our proposed algorithms with acceptable complexity have a good performance comparing with the optimal performance

Resource Allocation for Network-Integrated Device-to-Device Communications Using Smart Relays

With increasing number of autonomous heterogeneous devices in future mobile networks, an efficient resource allocation scheme is required to maximize network throughput and achieve higher spectral efficiency. In this paper, performance of network-integrated device-to-device (D2D) communication is investigated where D2D traffic is carried through relay nodes. An optimization problem is formulated for allocating radio resources to maximize end-to-end rate as well as conversing QoS requirements for cellular and D2D user equipment under total power constraint. Numerical results show that there is a distance threshold beyond which relay-assisted D2D communication significantly improves network performance when compared to direct communication between D2D peers

Real-time Optimal Resource Allocation for Embedded UAV Communication Systems

We consider device-to-device (D2D) wireless information and power transfer systems using an unmanned aerial vehicle (UAV) as a relay-assisted node. As the energy capacity and flight time of UAVs is limited, a significant issue in deploying UAV is to manage energy consumption in real-time application, which is proportional to the UAV transmit power. To tackle this important issue, we develop a real-time resource allocation algorithm for maximizing the energy efficiency by jointly optimizing the energy-harvesting time and power control for the considered (D2D) communication embedded with UAV. We demonstrate the effectiveness of the proposed algorithms as running time for solving them can be conducted in milliseconds.Comment: 11 pages, 5 figures, 1 table. This paper is accepted for publication on IEEE Wireless Communications Letter

Delay-Optimal Relay Selection in Device-to-Device Communications for Smart Grid

The smart grid communication network adopts a hierarchical structure which consists of three kinds of networks which are Home Area Networks (HANs), Neighborhood Area Networks (NANs), and Wide Area Networks (WANs). The smart grid NANs comprise of the communication infrastructure used to manage the electricity distribution to the end users. Cellular technology with LTE-based standards is a widely-used and forward-looking technology hence becomes a promising technology that can meet the requirements of different applications in NANs. However, the LTE has a limitation to cope with the data traffic characteristics of smart grid applications, thus require for enhancements. Device-to-Device (D2D) communications enable direct data transmissions between devices by exploiting the cellular resources, which could guarantee the improvement of LTE performances. Delay is one of the important communication requirements for the real-time smart grid applications. In this paper, the application of D2D communications for the smart grid NANs is investigated to improve the average end-to-end delay of the system. A relay selection algorithm that considers both the queue state and the channel state of nodes is proposed. The optimization problem is formulated as a constrained Markov decision process (CMDP) and a linear programming method is used to find the optimal policy for the CMDP problem. Simulation results are presented to prove the effectiveness of the proposed scheme