Optimal Power Allocation for Multi-relay Cooperative Transmission Scheme with STBC
Date Issued
2008
Date
2008
Author(s)
Yu, Yu-Jui
Abstract
Cooperative communications offer an effective way to mitigate fading under multi-user environment. By coordinating numerous single-antenna mobiles to share their antennas efficiently and establish a virtual Multiple-Input-Multiple-Output (MIMO) array, not only can this new class of techniques extract transmit diversity, it can also enhance the transmission quality. However, in a resource-constrained wireless network, the performance varies greatly depending on the effectiveness of power allocation strategy.eanwhile, it has been proven that MIMO capacity enhancement techniques such as Space-Time Block Codes (STBC) can be incorporated into cooperative relaying system to achieve full-rate and full-diversity data transmission. Needless to say, efficient power allocation among mobile users is necessary in order to reap the benefits of cooperative communications.n this thesis, we first discuss the fundamental principles of cooperative communications. Next, we explore the possibilities of incorporating a MIMO capacity enhancement technique known as Space-Time Block Codes (STBC) into cooperative relaying system. Then, the power allocation (PA) strategy for both amplify-and-forward relay protocol and decode-and-forward relay protocol are analyzed under two cases: with and without channel knowledge at the transmitter. After that, we document the power allocation scheme between two relay stations under power constraint for a non-regenerative relaying system based on STBC [10]. Although numerical results demonstrate that this PA scheme outperforms uniform PA scheme with or without diversity path signal, it is subjected to several constraints. Finally, we propose a novel power allocation scheme that enables the two relays to communicate with each other. Thus, user cooperative transmission can be exploited to extract user cooperative diversity. Finally, simulation and analysis results are presented to demonstrate the advantages of our proposed PA scheme.
Subjects
cooperative communications
optimal power allocation (PA)
space-time block codes (STBC)
non-regenerative relaying system
Type
thesis
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