[论文解读] Cooperative Energy Trading in CoMP Systems Powered by Smart Grids

Jie Xu, Rui Zhang|arXiv (Cornell University)|Mar 23, 2014

Advanced MIMO Systems Optimization参考文献 18被引用 6

一句话总结

本文提出了一种在智能电网供电的蜂窝网络中，针对协作能源交易与协调多点（CoMP）传输的联合优化框架，利用凸优化和上行-下行对偶性，以最小化总能耗成本。通过使基站能够与电网进行能源交易，同时在QoS约束下联合管理发射预编码，该方法在示例场景中实现了高达86%的成本降低。

ABSTRACT

This paper studies the energy management in the coordinated multi-point (CoMP) systems powered by smart grids, where each base station (BS) with local renewable energy generation is allowed to implement the two-way energy trading with the grid. Due to the uneven renewable energy supply and communication energy demand over distributed BSs as well as the difference in the prices for their buying/selling energy from/to the gird, it is beneficial for the cooperative BSs to jointly manage their energy trading with the grid and energy consumption in CoMP based communication for reducing the total energy cost. Specifically, we consider the downlink transmission in one CoMP cluster by jointly optimizing the BSs' purchased/sold energy units from/to the grid and their cooperative transmit precoding, so as to minimize the total energy cost subject to the given quality of service (QoS) constraints for the users. First, we obtain the optimal solution to this problem by developing an algorithm based on techniques from convex optimization and the uplink-downlink duality. Next, we propose a sub-optimal solution of lower complexity than the optimal solution, where zero-forcing (ZF) based precoding is implemented at the BSs. Finally, through extensive simulations, we show the performance gain achieved by our proposed joint energy trading and communication cooperation schemes in terms of energy cost reduction, as compared to conventional schemes that separately design communication cooperation and energy trading.

研究动机与目标

• 为应对密集蜂窝网络中不断上升的运营成本，通过整合可再生能源和与智能电网的双向能源交易来解决该问题。
• 克服传统CoMP设计忽略动态电价和可再生能源供应波动性的局限性。
• 联合优化CoMP系统中的能源交易与预编码，以在满足QoS要求的前提下最小化总能耗成本。
• 为实际部署开发最优与次优解，采用低复杂度的ZF预编码方案作为可扩展的替代方案。

提出的方法

• 建立一个联合优化问题，通过能源交易与CoMP预编码在QoS和功率约束下最小化总能耗成本。
• 应用上行-下行对偶性，将非凸的下行链路问题转化为适合凸优化的对偶上行链路问题。
• 使用拉格朗日松弛与次梯度方法，结合椭球法迭代求解对偶问题。
• 通过Karush-Kuhn-Tucker（KKT）条件与对偶分解推导出最优能源交易与预编码方案。
• 提出一种次优的基于ZF的预编码方案，以降低计算复杂度，同时保持良好性能。
• 通过仿真验证方法，将联合优化与传统的CoMP与能源交易分别设计的方案进行对比。

实验结果

研究问题

• RQ1 如何在智能电网供电的蜂窝网络中联合优化能源交易与CoMP传输，以最小化总能耗成本？
• RQ2 与传统的CoMP设计或孤立的能源交易设计相比，联合优化的性能增益如何？
• RQ3 在考虑可变电网电价的情况下，双向能源交易的引入如何影响系统成本与能效？
• RQ4 在现实约束下，能源与预编码管理在最优性与复杂度之间存在何种权衡？
• RQ5 基站之间可再生能源供应的差异性如何影响协作能源交易的有效性？

主要发现

• 在示例场景中，所提出的联合优化方案将总能耗成本降低了86%，从0.356单位降至0.05单位，相较于传统CoMP设计。
• 最优解通过协调能源交易与预编码实现成本最小化，且根据KKT条件精确推导出能源购买/出售水平。
• 次优的基于ZF的方案显著降低了计算复杂度，同时保持了优异的性能，适用于实时部署。
• 当协作同时涵盖能源交易与通信协调时，能耗成本节约显著高于将两者分开处理的情况。
• 即使在基站间可再生能源发电不均且电网电价波动的情况下，系统仍能实现显著的成本降低。