Channel Relay

Topics: Rayleigh fading, Fading, Wireless Pages: 56 (12598 words) Published: June 20, 2013
VOL. 3, NO. 7 July, 2012

Journal of Emerging Trends in Computing and Information Sciences ©2009-2012 CIS Journal. All rights reserved. http://www.cisjournal.org

ISSN 2079-8407

Performance Analysis of Cooperative Communication Protocols
1

Rahat Ali Khan, 2 Muhammad Abdul Aleem, 1 Asad Ali Shaikh
Institute of Information and Communication Technology, University of Sindh Jamshoro Sindh Pakistan Post code: 76080 2 College of Engineering, PAFKIET Karachi Corresponding Author: 1 rahataliikhan@yahoo.com 1

ABSTRACT
With the rapid growth of multimedia services, future generations of cellular communications require higher data rates and a more reliable transmission link while keeping satisfactory quality of service. In this respect, multiple input multiple-output (MIMO) antenna systems have been considered as an efficient approach to address these demands by offering significant multiplexing and diversity gains over single antenna systems without increasing requirements on radio resources such as bandwidth and power. Although MIMO systems can unfold their huge benefit in cellular base stations, they may face limitations when it comes to their deployment in mobile handsets. To overcome this drawback, in cellular networks, relays (fixed or mobile terminals) can cooperate to improve the overall system performance. For example, once the transmission from a base station with multiple antennas is received by multiple nodes (fixed relays and/or mobiles); they can exchange information to enhance the quality of intended signals while suppressing interference. On the other hand, when a mobile user wants to communicate with the base station, but the link in between is too weak, and then the other nearby mobile users cooperates and shares their antennas to assist the direct communication. With this approach, the benefits of MIMO systems can be attained in a distributed fashion. Furthermore, cooperative communications can efficiently combat the severity of fading and shadowing effects through the assistance of relays. It has been shown that using relays the capacity and coverage of cellular networks can be extended without increasing the mobile transmit power or demanding for an extra bandwidth. This paper is based on cooperative communications in wireless networks. We focus on Bit error rate (BER) performance analysis of cooperative communications with either an amplify-and-forward (AF) or decode-and-forward (DF) cooperation protocol using Matlab. We consider the single and multi relay scenario in these simulations. Keywords: MIMO, BER, Protocols

1. INTRODUCTION
The success of IP technologies jointly with high data rate solutions at physical layer led to a rapid growth of telecommunications networks. However, radio resources are limited (and expensive) and one cannot infinitely increase the network capacity. The availability of vacant bandwidth is not expected to increase significantly. To date, the only way to get around this is by controlling the transmission power and increasing the spatial reuse of frequencies by cell spitting/sectoring. These were the driving principles behind the design of cellular networks of the past (Analog Mobile Phone system (AMPS), Global system for Mobile Communication (GSM) and also 3rdGeneration (3G)). However, these methods incur huge installation and maintenance costs in 3G Universal Mobile Telecommunication system (UMTS) / Code Division Multiple Access (CDMA) 2000 and 4G Long Term Evolution (LTE) / worldwide interoperability for Microwave Access (WiMAX) networks where micro cells have a diameter of a few hundred meters. Further high license fee is an issue; there is thus a threat that high-quality wireless services may soon become an unaffordable luxury [1]. An extreme alternative are ad hoc networks, where packets are forwarded in a multi-hop fashion. In such networks, users cooperate to relay and process each other’s information. Ad hoc networks are characterized by their low cost, rapid...

References: VOL. 3, NO. 7 July, 2012
Journal of Emerging Trends in Computing and Information Sciences
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