Theoretical Limitation of Adaptive Modulation in Multinode Decode-and-Forward Cooperative Communication Systems
碩士 === 國立中興大學 === 電機工程學系所 === 99 === Adaptive modulation has been shown to increase the system efficiency of multinode decode-and-forward cooperative communication systems. However, its theoretical limitation in such a system still remains unknown. In this work, we investigate this issue by consi...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2011
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| Online Access: | http://ndltd.ncl.edu.tw/handle/15142473692093341921 |
| Summary: | 碩士 === 國立中興大學 === 電機工程學系所 === 99 === Adaptive modulation has been shown to increase the system efficiency of multinode
decode-and-forward cooperative communication systems. However, its theoretical
limitation in such a system still remains unknown. In this work, we investigate
this issue by considering two ideal protocols, Protocol I and Protocol II. One aims at
achieving the maximum rate and the other focuses on having the best efficiency. The
theoretical results such as the distribution of modulation levels, the average achievable
rate and the efficiency of these two protocols are derived and validated through
extensive computer simulations. Furthermore, we propose a protocol to achieve the
theoretical limitation of adaptive modulation in a multinode decode-and-forward cooperative
communication system as possible. The proposed mechanism is to select
a modulation scheme and the helping relay nodes to fulfill the requirement of outage
probability while maximizing the rate and efficiency as possible. The proposed
mechanism is compared against the popular SNR-based mechanism. It is shown
that the proposed mechanism is able to provide better average rate while having
comparable efficiency to the SNR-based mechanism.
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