Degrees of Freedom in Wireless Interference Networks With Cooperative Transmission and Backhaul Load Constraints
Degrees of Freedom in Wireless Interference Networks With Cooperative Transmission and Backhaul Load Constraints
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DOI：
10.1109/tit.2019.2914462
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发表时间：
2019-09-01
影响因子：
2.5
通讯作者：
Veeravalli, Venugopal V.
中科院分区：
文献类型：
--
作者：
Bande, Meghana;El Gamal, Aly;Veeravalli, Venugopal V.
研究了在回程负载约束下无线网络中协作传输的自由度（DoF）增益，回程负载约束限制了从集中式控制器到基站发送器的平均消息数。回程负载被定义为每个信道使用在所有发射机处可用的所有消息的总和，由用户数量归一化。对于Wyner的线性干扰网络，其中每个发射机连接到具有相同索引的接收机以及一个后继接收机，每个用户的自由度的特点，并提出了最佳方案。此外，它示出的最佳分配的消息发送器是不对称的，并满足本地合作的约束和最佳的编码方案只依赖于一次性的合作迫零发送波束成形。使用的见解从分析Wyner的线性干扰网络，结果被扩展到更实际的六边形扇区蜂窝网络，和编码方案的基础上合作迫零，以提供显着的自由度增益。它是建立，通过允许合作传输和灵活的消息分配，仅受平均回程负载的约束，可以提供的速率增益所承诺的信息理论上界与实际的一次计划，很少或没有额外的负载上的回程。最后，有用的上限上的每用户自由度的计划的基础上合作迫零的平均回程负载约束的较低的值，并制定了一个优化框架的一般匡威问题。
Degrees of freedom (DoFs) gains are studied in wireless networks with cooperative transmission under a backhaul load constraint that limits the average number of messages that can be delivered from a centralized controller to base station transmitters. The backhaul load is defined as the sum of all the messages available at all the transmitters per channel use, normalized by the number of users. For Wyner's linear interference network, where each transmitter is connected to the receiver having the same index as well as one succeeding receiver, the per user DoF is characterized and the optimal scheme is presented. Furthermore, it is shown that the optimal assignment of messages to transmitters is asymmetric and satisfies a local cooperation constraint and the optimal coding scheme relies only on one-shot cooperative zero-forcing transmit beamforming. Using insights from the analysis of Wyner's linear interference network, the results are extended to the more practical hexagonal sectored cellular network, and coding schemes based on cooperative zero-forcing are shown to deliver significant DoF gains. It is established that by allowing for cooperative transmission and a flexible message assignment that is constrained only by an average backhaul load, one can deliver the rate gains promised by information-theoretic upper bounds with practical one-shot schemes that incur little or no additional load on the backhaul. Finally, useful upper bounds on the per user DoF for schemes based on cooperative zero-forcing are presented for lower values of the average backhaul load constraint, and an optimization framework is formulated for the general converse problem.