Survey of Resource Allocation Techniques in Cooperative Communication Usha Padma* H.V.Kumaraswamy* and S.Ravi Shankar** *Department of Telecommunication Engineering, R.V.College of Engineering, Bengaluru kamakshimb@rvce.edu.in, kumaraswamyhv@rvce.edu.in **Electronics and Communication engineering, R.V.College of Engineering, Bengaluru ravishankars@rvce.edu.in Abstract: One of the solutions for edge users and low power devices in wireless networks is Cooperative communication(CC) and is expected to be an emerging technology for efficient use of resources in future. The basic unit in CC is a three terminal network where the relay cooperate with the source by sharing its resources, to make successful communication between source and destination. There is a need to allocate resources efficiently in CC to overcome the challenges and demands of next generation wireless networks. A survey of different methods of allocating resources in CC is discussed. We provide an overview of objectives, protocols, network configuration , decision types and literature of resource allocation in CC. Keywords: Resource allocation, Cooperative communication, Decision types, Network configuration, Objectives. Introduction There are high increase of mobile users in today’s world where there is a very high demand on the data transmission rate and channel bandwidth. The wireless communication has to overcome challenges such as fading, Doppler shift etc. The promising multiple input multiple output (MIMO) technology has served this purpose, but there is extra use of hardware i.e., antenna and usage of power. To overcome these impairments that are found in wireless, “cooperative communication” or diversity techniques have been proposed. Co-operative communication uses the co-operative techniques where devices co- operate to transmit the signals over the air which exploits distributed form of spatial diversity that mitigates the negative effects of signal fading, interference etc. Direct communication or point to point communication is the one in which communication exists between sources(S) and destination(D) may be base station or mobile. For co-operative communication, user co-operation is made possible whenever there is at least one additional node. Co-operative communication is regarded as virtual MIMO system, which can efficiently mitigate the fading multipath channel. It creates an independent path between source and destination i.e., it acts as an auxiliary channel to the existing point to point communication. CC protocols can be categorized into fixed relaying(FR) and adaptive relaying(AR) schemes. In FR schemes the available channel resource is divided among source and relay. In case of adaptive, comprising selective and incremental relaying are allowed. Allocation of Resources in Cooperative Communication This section briefs about the types of resources that can be allocated in CC. Types of the resources include : Power, Relay, User scheduling, Routing, Quality of service, Delay, Time slot, Bandwidth and Subcarrier. Power In any wireless communication system, maximum power is consumed by the RF devices (Communication unit). Hence there is requirement to allocate power efficiently to source and relay. Maximum researches have contributed towards allocation of this element in CC.In [2],[5],[7], [9], [12],[13],[14],[22] , and [25], authors investigated different optimal power allocation(PA) methods. Adaptive PA method was investigated by [3] under power constraint, according to fading state information and [6] subject to the constraint of available energy. An incremental power assignment algorithm, based on the knowledge of the average channel power attenuation and combining method at the receiving node was proposed in [8].Game theoretic approach is applied on source and relays, to allocate power in [10]and [16]. In [10], source nodes buy power from relay nodes. Here relays attract source nodes by setting proper prices. In [16], two source nodes cooperate each other by relaying each other’s data. Authors designed power auction scheme to allocate power to the relay nodes and the same was extended in [20], where a node was made to act as both seller as well as buyer and the price of the auctioneer was announced independently. Contract theory and auction mechanisms were combined so as to provide maximum possible