自适应主导时域采样选择的低复杂度PTS策略

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"本文提出了一种低复杂度的PTS(部分传输序列)方案,该方案针对OFDM(正交频分复用)系统中的峰值到平均功率比(PAPR)问题进行了优化。通过在时间域中自适应选择主导样本,提高了PTS计算效率,同时保持了接近最优的PAPR降低性能,降低了计算复杂性。关键词包括:自适应样本旋转、主导时间域样本、PTS、PAPR、OFDM系统" 在无线通信领域,OFDM系统因其高效的频谱利用率和抗多径衰落能力而广泛采用。然而,OFDM信号的一个显著缺点是其较高的PAPR,这可能导致功率放大器工作在非线性区,引入失真并降低系统的能源效率。为了解决这个问题,PTS方法被提出,它通过分割信号序列并采用不同的相位旋转来降低PAPR。 传统的PTS方法通常涉及到大量的计算,因为它需要对所有可能的子块组合进行评估,以找到导致最低PAPR的组合。这在处理高数据速率和大系统尺寸时会带来相当大的计算负担。因此,寻求一种低复杂度的PTS策略至关重要。 本文提出的低复杂度PTS方案通过自适应地在每个时间域样本上选择主导样本来进行样本旋转,从而减少了计算量。这种自适应选择方法能够在不显著牺牲PAPR降低性能的前提下,显著减少所需的计算资源。相比于传统的PTS算法,该方法更加高效,尤其是在处理大规模OFDM系统时。 具体来说,论文中可能会详细阐述以下几点: 1. PTS方案的基础理论和传统实现方式,以及其在PAPR降低方面的挑战。 2. 自适应样本选择的算法设计,包括如何确定主导样本和如何进行时间域子块的旋转。 3. 模拟和实验结果,对比传统PTS方法,展示新方法在PAPR降低性能和计算复杂度之间的权衡。 4. 对不同系统参数(如子载波数量、符号长度)的影响分析,以证明方法的普适性和灵活性。 5. 讨论可能的优化方向和未来研究的潜在领域,例如进一步降低复杂度或探索其他与PTS结合的PAPR降低技术。 这篇论文为解决OFDM系统的PAPR问题提供了一个创新且实用的解决方案,通过自适应时间域主导样本选择的PTS策略,实现了高效且低复杂度的PAPR管理,对实际无线通信系统的设计具有重要的参考价值。

Algorithm 1: The online LyDROO algorithm for solving (P1). input : Parameters V , {γi, ci}Ni=1, K, training interval δT , Mt update interval δM ; output: Control actions 􏰕xt,yt􏰖Kt=1; 1 Initialize the DNN with random parameters θ1 and empty replay memory, M1 ← 2N; 2 Empty initial data queue Qi(1) = 0 and energy queue Yi(1) = 0, for i = 1,··· ,N; 3 fort=1,2,...,Kdo 4 Observe the input ξt = 􏰕ht, Qi(t), Yi(t)􏰖Ni=1 and update Mt using (8) if mod (t, δM ) = 0; 5 Generate a relaxed offloading action xˆt = Πθt 􏰅ξt􏰆 with the DNN; 6 Quantize xˆt into Mt binary actions 􏰕xti|i = 1, · · · , Mt􏰖 using the NOP method; 7 Compute G􏰅xti,ξt􏰆 by optimizing resource allocation yit in (P2) for each xti; 8 Select the best solution xt = arg max G 􏰅xti , ξt 􏰆 and execute the joint action 􏰅xt , yt 􏰆; { x ti } 9 Update the replay memory by adding (ξt,xt); 10 if mod (t, δT ) = 0 then 11 Uniformly sample a batch of data set {(ξτ , xτ ) | τ ∈ St } from the memory; 12 Train the DNN with {(ξτ , xτ ) | τ ∈ St} and update θt using the Adam algorithm; 13 end 14 t ← t + 1; 15 Update {Qi(t),Yi(t)}N based on 􏰅xt−1,yt−1􏰆 and data arrival observation 􏰙At−1􏰚N using (5) and (7). i=1 i i=1 16 end With the above actor-critic-update loop, the DNN consistently learns from the best and most recent state-action pairs, leading to a better policy πθt that gradually approximates the optimal mapping to solve (P3). We summarize the pseudo-code of LyDROO in Algorithm 1, where the major computational complexity is in line 7 that computes G􏰅xti,ξt􏰆 by solving the optimal resource allocation problems. This in fact indicates that the proposed LyDROO algorithm can be extended to solve (P1) when considering a general non-decreasing concave utility U (rit) in the objective, because the per-frame resource allocation problem to compute G􏰅xti,ξt􏰆 is a convex problem that can be efficiently solved, where the detailed analysis is omitted. In the next subsection, we propose a low-complexity algorithm to obtain G 􏰅xti, ξt􏰆. B. Low-complexity Algorithm for Optimal Resource Allocation Given the value of xt in (P2), we denote the index set of users with xti = 1 as Mt1, and the complementary user set as Mt0. For simplicity of exposition, we drop the superscript t and express the optimal resource allocation problem that computes G 􏰅xt, ξt􏰆 as following (P4) : maximize 􏰀j∈M0 􏰕ajfj/φ − Yj(t)κfj3􏰖 + 􏰀i∈M1 {airi,O − Yi(t)ei,O} (28a) τ,f,eO,rO 17 ,,actor模型和critic模型在哪

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