论文标题
通过压缩继电器的多访问和广播频道之间的上行链路 - 下链链接二元性
Uplink-Downlink Duality Between Multiple-Access and Broadcast Channels with Compressing Relays
论文作者
论文摘要
Uplink-downlink二元性是指以下事实：在总和约束下，高斯多个访问频道的容量区域和具有Hermitian thrasts频道矩阵的高斯广播频道是相同的。本文将此结果推广到合作的蜂窝网络，在该网络中，在中央处理器（CP）的协调下为用户服务时，将远程访问点部署为继电器。在此模型中，用户和继电器是通过嘈杂的无线链接连接的，而继电器和CP是通过无噪声连接的，而无频率有限的fronthaul链接。基于Lagrangian技术，本文在继电器使用基于压缩的策略的假设下，建立了这种多访问接力渠道与广播接力渠道之间的双重关系。具体而言，我们表明，在相同的总发射功率约束和单个方面的速率约束下，使用独立压缩或Wyner-ZIV或WYNER-ZIV和多变量压缩策略时，高斯多访问和广播中继渠道的可实现速率区域是相同的。 The key observations are that if the beamforming vectors at the relays are fixed, the sum-power minimization problems under the achievable rate and fronthaul constraints in both the uplink and the downlink can be transformed into either a linear programming or a semidefinite programming problem depending on the compression technique, and that the uplink and downlink problems are Lagrangian duals of each other.此外，对应于下行链路率约束的双变量成为上行链路幂。对应于下行链路Fronthaul约束的双变量成为上行链路量化噪声。这种二元性关系使有效的算法可以优化基于上行链路的下行链路传输和中继策略。
Uplink-downlink duality refers to the fact that under a sum-power constraint, the capacity regions of a Gaussian multiple-access channel and a Gaussian broadcast channel with Hermitian transposed channel matrices are identical. This paper generalizes this result to a cooperative cellular network, in which remote access-points are deployed as relays in serving the users under the coordination of a central processor (CP). In this model, the users and the relays are connected over noisy wireless links, while the relays and the CP are connected over noiseless but rate-limited fronthaul links. Based on a Lagrangian technique, this paper establishes a duality relationship between such a multiple-access relay channel and broadcast relay channel, under the assumption that the relays use compression-based strategies. Specifically, we show that under the same total transmit power constraint and individual fronthaul rate constraints, the achievable rate regions of the Gaussian multiple-access and broadcast relay channels are identical, when either independent compression or Wyner-Ziv and multivariate compression strategies are used. The key observations are that if the beamforming vectors at the relays are fixed, the sum-power minimization problems under the achievable rate and fronthaul constraints in both the uplink and the downlink can be transformed into either a linear programming or a semidefinite programming problem depending on the compression technique, and that the uplink and downlink problems are Lagrangian duals of each other. Moreover, the dual variables corresponding to the downlink rate constraints become the uplink powers; the dual variables corresponding to the downlink fronthaul constraints become the uplink quantization noises. This duality relationship enables an efficient algorithm for optimizing the downlink transmission and relaying strategies based on the uplink.
