Quality-of-service driven power and rate adaptation for multichannel communications over wireless links
Quality-of-service driven power and rate adaptation for multichannel communications over wireless links
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DOI：
10.1109/twc.2007.06031
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发表时间：
2007-12
影响因子：
10.4
通讯作者：
Jia Tang;Xi Zhang
中科院分区：
文献类型：
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作者：
Jia Tang;Xi Zhang
我们为无线链路上的多通道通信系统提出了一种服务质量（QoS）驱动的功率和速率自适应方案。特别是，我们使用多通道通信对分集或多路复用系统的概念架构进行建模，这在移动无线网络的物理层演进中发挥着基础作用。通过将信息论与有效容量的概念相结合，我们提出的方案旨在在给定的延迟 QoS 约束下最大化多通道系统吞吐量。在凸优化的框架下，我们开发了最优自适应算法。我们的分析表明，当 QoS 约束变得宽松时，最优功率控制策略收敛于众所周知的注水方案，其中可以实现香农（或遍历）容量。另一方面，当QoS约束变得严格时，最优策略收敛到以恒定速率（即零中断容量）运行的方案，该方案仅使用有限数量的子信道，接近香农容量。这一观察结果表明，随着 QoS 约束变得更加严格，最佳有效容量函数从遍历容量降低到零中断容量。此外，与单通道通信不同的是，单通道通信必须牺牲吞吐量来提供QoS，而多通道通信可以同时实现高吞吐量和严格的QoS。
We propose a quality-of-service (QoS) driven power and rate adaptation scheme for multichannel communications systems over wireless links. In particular, we use multichannel communications to model the conceptual architectures for either diversity or multiplexing systems, which play a fundamental role in physical-layer evolutions of mobile wireless networks. By integrating information theory with the concept of effective capacity, our proposed scheme aims at maximizing the multichannel-systems throughput subject to a given delay-QoS constraint. Under the framework of convex optimization, we develop the optimal adaptation algorithms. Our analyses show that when the QoS constraint becomes loose, the optimal power-control policy converges to the well-known water-filling scheme, where the Shannon (or ergodic) capacity can be achieved. On the other hand, when the QoS constraint gets stringent, the optimal policy converges to the scheme operating at a constant-rate (i.e., the zero-outage capacity), which, by using only a limited number of subchannels, approaches the Shannon capacity. This observation implies that the optimal effective capacity function decreases from the ergodic capacity to the zero-outage capacity as the QoS constraint becomes more stringent. Furthermore, unlike the single-channel communications, which have to trade off the throughput for QoS provisioning, the multichannel communications can achieve both high throughput and stringent QoS at the same.