Radio Resource Allocation for OFDM-Based Dynamic Spectrum Sharing: Duality Gap and Time Averaging
Radio Resource Allocation for OFDM-Based Dynamic Spectrum Sharing: Duality Gap and Time Averaging
复制标题
DOI：
10.1109/jsac.2014.2361080
复制
发表时间：
2015-05
影响因子：
16.4
通讯作者：
M. Khoshkholgh;N. Mokari;K. Navaie;H. Yanikomeroglu;Victor C. M. Leung;K. Shin
中科院分区：
文献类型：
--
作者：
M. Khoshkholgh;N. Mokari;K. Navaie;H. Yanikomeroglu;Victor C. M. Leung;K. Shin
本文考虑基于正交频分多址 (OFDM) 的频谱共享网络下行链路中的无线资源分配 (RRA)。 RRA的目标是在主服务干扰阈值和次服务发射功率约束的情况下最大化平均可实现的吞吐量。 RRA 通常基于时间窗口 T 来实现，在时间窗口 T 上对系统参数进行平均并根据资源限制进行检查。我们分别使用短期（T=1 个时隙）和长期（T≫1 个时隙）平均作为瞬时约束和平均约束的近似值。还针对具有长期干扰阈值和短期干扰阈值约束的系统研究了 RRA。 RRA优化是一种采用对偶原理求得近似解的非凸优化问题。对偶间隙表示由此获得的解的近似程度。我们证明了与每个资源分配相对应的对偶间隙至少以 T 的指数率渐近衰减。我们进一步证明 OFDMA 是渐近的最佳子载波分配。我们还提出了一种可实际实现的在线功率和子载波分配以及动态信道状态信息测量。我们进行了广泛的仿真研究，以验证理论上预测的对偶间隙行为，并研究不同系统参数对二次服务性能的影响。所开发的算法还经过验证，在实际设置中具有鲁棒性，并且快速收敛到理论界限，因此实际上是可实现的。
This paper considers radio resource allocation (RRA) in the downlink of an orthogonal frequency division multiple access (OFDM)-based spectrum-sharing network. The objective of RRA is to maximize the average achievable throughput subject to the primary service interference threshold and the secondary service transmit power constraint. RRA is usually implemented based on a time window T over which system parameters are averaged and checked against resource constraints. We use short-term ( T=1 time slot) and long-term ( T ≫ 1 slots) averaging as approximations to instantaneous and average constraints, respectively. RRA is also investigated for this system with long-term interference threshold and short-term interference threshold constraints. RRA optimization is a nonconvex optimization problem in which the duality principle is adopted to obtain approximate solutions. The duality gap indicates the degree of approximation in the thus-obtained solution. We prove that the duality gap corresponding to each resource allocation asymptotically decays at least with an exponential rate of T. We further show that OFDMA is, asymptotically, the optimal subcarrier assignment. We also propose a practically implementable online power and subcarrier allocation with on-the-fly channel state information measurement. An extensive simulation study has been conducted to verify the theoretically predicted duality gap behavior and to investigate the impact of different system parameters on the secondary service performance. The developed algorithms are also validated to be robust in practical settings and converge fast to theoretical bounds, and thus practically implementable.