Power Allocation for OFDM-Based Cognitive Radio Systems under Primary User Activity
Power Allocation for OFDM-Based Cognitive Radio Systems under Primary User Activity
复制标题
主要用户活动下基于 OFDM 的认知无线电系统的功率分配
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
Chin
中科院分区：
文献类型：
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作者：
Chiuan;Chin
针对正交频分复用认知无线电系统，提出了一种基于主用户活动的有效功率分配算法。由于PU活动，功率分配优化问题变为最大化总和预期容量（即，总容量减去预期容量损失），而不是在传统功率分配优化问题中最大化总容量。为了有效地解决这个问题，我们首先将期望容量损失转化为峰值功率约束，然后将问题转化为在峰值功率约束下最大化总容量。通过这个问题的重新表述，可以通过迭代地执行注水（WF）算法来达到最优功率分布。代替使用WF算法，我们还提出了一种简单的方法来更新水位。仿真结果表明，所提出的方法实现了一个总和的预期容量接近的最优解，而不管改变的概率，PU将重新占用的子载波。
This paper presents an efficient power allocation algorithm based on primary user (PU) activity for orthogonal frequency division multiplexing cognitive radio systems. Because of PU activity, the power allocation optimization problem becomes maximizing the sum expected capacity (i.e., the sum capacity minus the expected capacity loss), rather than maximizing the sum capacity in the traditional power allocation optimization problem. To solve this problem efficiently, we first transform the expected capacity loss into the peak power constraint and then reformulate the problem as maximizing the sum capacity under the peak power constraint. With this problem reformulation, the optimal power distribution can be reached by iteratively performing the water-filling (WF) algorithm. Instead of using the WF algorithm, we also propose a simple method to update the water level. Simulation results show that the proposed approach achieves a sum expected capacity close to that of the optimal solution, regardless of the change in the probability that the PU will reoccupy the subcarriers.