Performance Analysis of Cooperative Communication Protocols

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 increasin