Authors: Gaofei Huang Liping Luo Guangchi Zhang Ping Yang Dong Tang Jiayin Qin
Publish Date: 2012/10/29
Volume: 71, Issue: 3, Pages: 1597-1618
Abstract
In this paper we investigate the qualityofservice QoS driven subcarrier pairing and power allocation for twohop decodeandforward DF OFDM relay systems By integrating the concept of effective capacity our goal is to maximize the system throughput subject to a given delayQoS constraint Based on whether the destination can receive the signal transmitted by the source we consider two scenarios ie OFDM DF relay systems without diversity and OFDM DF relay systems with diversity respectively For OFDM DF relay systems without diversity we demonstrate that the jointly optimal subcarrier pairing and power allocation can be implemented with two separate steps For OFDM DF relay systems with diversity we propose an iterative algorithm to achieve jointly optimal subcarrier pairing and power allocation Furthermore we find that the analytical results show different conclusions for the two types of OFDM relay systems For OFDM relay systems without diversity the optimal power allocation depend on not only the channel quality of subcarriers but also the delay QoS constraints while the optimal subcarrier pairing just depends on the channel quality of subcarriers For OFDM relay systems with diversity both the optimal subcarrier pairing and power allocation depend on the channel quality of subcarriers and the delay QoS constraints Simulation results show that our proposed scheme offers a superior performance over the existing schemes
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