1	  	  	  Performance Analysis of Power Allocation andRelay Location in a Cooperative RelayNetwork	  	  	  	  Muhammad H. D. Khan*, Mohammed S. Elmusrati**Communication and System Engineering Group, University of Vaasa, Wolffintie 34, 65200, Vaasa, Finland	  	  hazandanish@yahoo.com , moel@uwasa.fi,
Abstract—Transmission using cooperative relays is a new paradigm in wireless communication. The cooperating relays facilitate theprocess of communication by performing the operations like data transmission and data processing in a distributed manner. In this wirelesssystem every node is an active element and can act as a relay node. So when a group of these cooperating nodes are involved in acommunication stream, a virtual multiple input multiple output (MIMO) system is formed which provides the networks with additional
benefits of spectral efficiency and error reduction. Since this system is based on the traditional wireless sensor network (WSN) in which eachnode has a limited power and computational resource. Therefore, energy efficiency achieved by employing cooperating relays is not
sufficient enough. Some extra measures need to be taken to decrease the power consumption of the network. This paper is an effort in thisdirection, as a power efficient allocation algorithm has been proposed which allocates transmission power optimally to the source node andthe involved relay nodes. In the first part of the paper mathematical expressions have been derived for various phases in a cooperative relaytransmission. The performance efficiency of the system has been presented using average bit error rate (ABER) as a performance criteria.
In the second part, a power allocation algorithm has been derived and employed in a multi-hop cooperative relay network having 4-nodes,
with amplify and forward (AF) protocol as its relaying technique. The efficiency of the power allocation algorithm (OPA) has been further
investigated with respect to relay location in a network. Simulation results validate the performance efficiency of OPA in different
transmission scenarios.
Keyword—Power Allocation, Cooperative Relay Network, Multi-hop Transmission, Relaying Technique, Multiple Input Multiple Outputand Diversity Combining.	  	  	  	  	  	  	  	  	  	  	  	  	  Muhammad H. D. Khan (S’13) was born in Rawalpindi, Pakistan, in 1986. He received the B.E. degree in electrical engineering fromthe COMSATS Institute of Information Technology, Islamabad, Pakistan, in 2010, and the M.Sc. degree in technology from University ofVaasa, Vaasa, Finland, in 2013.
In 2010, he joined the Department of Avionics Engineering, Air University, Pakistan, as a Research Assistant, and in 2011 became a
Research Associate. His current research interests include wireless communication systems, sensor networks and resource allocationmanagement.

Mohammed Elmusrati (S’00-M’04-SM’12) received the B.Sc. (with honors) and M.Sc. (with high honors) degrees in telecommunicationengineering from the Electrical and Electronic Engineering Department, Benghazi University, Libya, in 1991 and 1995, respectively, andthe Licentiate of Science in technology (with distinction) and the Doctor of Science in Technology degrees in control engineering fromAalto University - Finland, in 2002 and 2004, respectively. Currently, Elmusrati is full professor and head of communications andsystems engineering group at University of Vaasa - Finland. Moreover, Elmusrati has Adjunct Professor position at Automation andSystems Technology Department at Aalto University. Elmusrati is a member of the Automation Society of Finland. Elmusrati haspublished more than 70 peer reviewed papers and reports. Moreover, he is coauthor for a textbook “SystemsEngineering in WirelessCommunications” Wiley 2009. His main research interests include Radio resource management in wireless communication, wirelessnetworked control, game theory, and smart grids.