Communication over fading channels with delay constraints
Communication over fading channels with delay constraints
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DOI：
10.1109/18.995554
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发表时间：
2002-05
期刊：
影响因子：
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通讯作者：
R. Berry;R. Gallager
中科院分区：
文献类型：
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作者：
R. Berry;R. Gallager
我们考虑用户在具有完美信道状态信息的衰落信道上进行通信。假设数据从某个更高层的应用程序到达，并存储在缓冲区中，直到被传输。我们研究了基于信道状态信息和缓存占用来调整用户的传输速率和功率，目标是同时调节业务所引起的长期平均传输功率和平均缓存延迟。讨论了这种情况的两种模型；一种对应于固定长度/可变速率码字，另一种对应于可变长度码字。分析了可靠通信所需的平均时延和平均发射功率之间的权衡。给出了求解所有帕累托最优功率/延迟运行点的动态规划公式。然后，我们量化了这种权衡在渐近大时滞条件下的行为。在这种情况下，我们刻画了简单的缓冲区控制策略，这些策略表现出最优的特征。文中还讨论了时延受限容量和衰落信道期望容量之间的关系。
We consider a user communicating over a fading channel with perfect channel state information. Data are assumed to arrive from some higher layer application and are stored in a buffer until transmitted. We study adapting the user's transmission rate and power based on the channel state information as well as the buffer occupancy; the objectives are to regulate both the long-term average transmission power and the average buffer delay incurred by the traffic. Two models for this situation are discussed; one corresponding to fixed-length/variable-rate codewords and one corresponding to variable-length codewords. The tradeoff between the average delay and the average transmission power required for reliable communication is analyzed. A dynamic programming formulation is given to find all Pareto optimal power/delay operating points. We then quantify the behavior of this tradeoff in the regime of asymptotically large delay. In this regime, we characterize simple buffer control policies which exhibit optimal characteristics. Connections to the delay-limited capacity and the expected capacity of fading channels are also discussed.