The downlink of a two-layered heterogeneous network is studied with macro basestations (MBs), small-cell basestations (SBs) that act as half-duplex analog relays, and mobile terminals (MTs). The first layer is a wireless backhaul layer between MBs and SBs, and the second is the transmission layer between SBs and MTs. The layers use the same time/frequency resources for communication, limiting the maximum per user degrees of freedom (puDoF) to half, due to the half-duplex nature of the SBs. For linear network models, it is established that the optimal puDoF can be achieved by cooperation with an appropriate number of antennas that depends on the connectivity of the network. The proposed zero-forcing schemes achieve cooperation without overloading the backhaul, through each MB sending an appropriate linear combination of MTs’ message signals to the SBs in the backhaul layer. The achievable schemes exploit the half-duplexity of the SBs, and schedule the SBs and MTs to be active in different time-slots to manage interference. These results are then extended to a more realistic hexagonal cellular network and it is shown that the optimal puDoF of half can be approached using only zero-forcing schemes.

中文翻译：

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具有无线回程的异构蜂窝网络的设计这项工作的部分内容在 ICASSP arxivcopy、ICCCN icccn 和 COMSNETS comsnets 上进行了介绍。

使用宏基站 (MB)、充当半双工模拟中继的小小区基站 (SB) 和移动终端 (MT) 来研究两层异构网络的下行链路。第一层是MB和SB之间的无线回程层，第二层是SB和MT之间的传输层。由于 SB 的半双工性质，这些层使用相同的时间/频率资源进行通信，将每个用户的最大自由度 (puDoF) 限制为一半。对于线性网络模型，确定可以通过与取决于网络连接性的适当数量的天线合作来实现最佳 puDoF。所提出的迫零方案在不使回程过载的情况下实现合作，通过每个 MB 向回程层中的 SB 发送 MT 消息信号的适当线性组合。可实现的方案利用 SB 的半双工性，并调度 SB 和 MT 在不同的时隙中活动以管理干扰。然后将这些结果扩展到更现实的六边形蜂窝网络，结果表明仅使用迫零方案就可以接近一半的最佳 puDoF。