A Load Balancing Scheme by D2D-Based Relay Communications in Heterogeneous Networks Signals

Heterogeneous networks have been regarded as an integral part of fifth generation communication networks in order to respond to the unprecedented growth of required data rates. In such networks, the existence of a variety of cells with base stations of varying capacities and transmit powers has enabled the repeated use of available bandwidth. Moreover, the excess load on the central base station can be directed to the sub-cell base stations. In the current work, a novel approach is proposed for such a load balancing problem in which some nodes previously connected to the main base station can be served by sub-cells through the use of some D2D relays. This will increase the overall network capacity, improve the quality of service (QoS) of cell edge users, and increase covered users. In this design, the maximization of the capacity of D2D links is formulated as an optimization problem which is not convex in general. To tackle this, the main problem is divided into two sub-problems of optimal resource allocation and user-relay pairing problems with much lower complexity. Simulation results demonstrate the superiority of the proposed method over existing works addressed in the literature.