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In this paper, we present a framework for resource allocations for multicast device-to-device (D2D) communications underlaying a cellular network. The objective is to maximize the sum throughput of active cellular users (CUs) and feasible D2D groups in a cell, while meeting a certain signal-to-interferenceplus-noise ratio (SINR) constraint for both the CUs and D2D groups. We formulate the problem of power and channel allocation as a mixed integer nonlinear programming (MINLP) problem where one D2D group can reuse the channels of multiple CUs and the channel of each CU can be reused by multiple D2D groups. Distinct from existing approaches in the literature, our formulation and solution methods provide an effective and flexible means to utilize radio resources in cellular networks and share them with multicast groups without causing harmful interference to each other. A variant of the generalized bender decomposition (GBD) is applied to optimally solve the MINLP problem. A greedy algorithm and a low-complexity heuristic solution are then devised. The performance of all schemes is evaluated through extensive simulations. Numerical results demonstrate that the proposed greedy algorithm can achieve closeto-optimal performance, and the heuristic algorithm provides good performance, though inferior than that of the greedy, with much lower complexity. I. INTRODUCTIONDevice-to-Device (D2D) communication is a technology component for Long Term Evolution-Advanced (LTE-A) of the Third Generation Partnership Project (3GPP) [1]. In D2D communication, 2 cellular users (CUs) in close proximity can exchange information over a direct link rather than transmitting and receiving signals through a cellular base station (BS). D2D users communicate directly while remaining controlled under the BS. Compared to routing through a BS, CUs at close proximity can save energy and resources when communicating directly with each other. Moreover, D2D users may experience high data rate and low transmission delay due to the short-range direct communication [2]. Reducing the network load by offloading cellular traffic from the BS and other network components to a direct path between users is another benefit of D2D communication reduce the network load and increase its effective capacity. Other benefits and usage cases are discussed in [3].The majority of the literature in D2D communications uses the cellular spectrum for both D2D and cellular communications,also known as in-band D2D [4]. Generally, in-band D2D falls in two categories, underlay and overlay [5]. Underlay in-band D2D can improve the spectrum efficiency of cellular networks by reusing cellular resources. Its main drawback lies in the interference caused by D2D users to cellular communications. Thus, efficient interference management and resource allocation are required to guarantee a target performance level of the cellular communication [6], [7]. In order to avoid this interference issue, it has also been proposed to dedicate part of the cellular resources to D2D communications in o...

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Vehicular Ad-hoc Networks (VANETs) will be an integral part of future Intelligent Transportation Systems (ITS). In highway settings where electrical power connections may not be available, road-side infrastructure will often be powered by renewable energy sources, such as solar power. For this reason, energy efficient designs are desirable.This thesis considers the problem of energy efficient downlink scheduling for roadside infrastructure. In the first part of the thesis, the constant bit rate (CBR) air interface case is investigated. Packet-based and timeslot-based scheduling models for the theoretical minimum energy bound are considered. Timeslot-based scheduling is then formulated as a Mixed Integer Linear Program (MILP). Following this, three energy efficient online scheduling algorithms with varying complexity are introduced. Results from a variety of experiments show that the proposed scheduling algorithms perform well when compared to the energy lower bounds.In the second part of the thesis, the variable bit rate (VBR) air interface option is consid-