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Abstract：
Multi-layer networks which consist of high-frequency cells and low-frequency cells in the same coverage area, can ensure capacity and coverage simultaneously. However, the existing handover algorithms in multi-layer networks result in the waste of spectrum resources. In this paper, we propose a new handover algorithm to address this gap. To ensure coverage and capacity, the proposed algorithm utilizes inter-frequency handover based on coverage and user throughput, encourages inter-frequency handover but suppresses intra-frequency handover. We provide a theoretical basis for this algorithm, whose superior performance has been verified by our simulations. Compared with the traditional algorithms, the proposed algorithm balances the load ratio between high-frequency cells and low-frequency cells from 30/90 to 60/80; Meanwhile, the proposed algorithm increases user throughput by at least 54.3% for the handover users; Moreover, the proposed algorithm increases the average signal interference plus noise ratio by about 1.5 dB for the high-frequency cells and 5 dB for the low-frequency cells, which gives rise to the increase in system capacity for 10.5% and 11.57% for downlink and uplink, respectively; Besides, the proposed algorithm decreases call blocking ratio by 38% and end-to-end delay by 5.82%.
摘要：
由同一覆盖范围内的高频小区和低频小区组成的多层网络，可以同时确保容量和覆盖范围。然而,多层网络中现有的切换算法造成了频谱资源的浪费。在本文中,我们提出了一种新的切换算法来解决这一差距。为了确保覆盖范围和容量，该算法利用基于覆盖和用户吞吐量的频率间切换，鼓励频率间切换，但抑制频率内切换。我们为该算法提供了理论基础,其优越的性能已被我们的仿真验证。与传统算法相比,该算法将高频小区和低频小区的负载比从30/90平衡到60/80;同时,该算法为切换用户增加了至少54.3%的用户吞吐量;此外,所提出的算法将高频小区的平均信号干扰加噪声比提高了约1.5dB，低频小区的平均信号干扰加噪声比提高了约5dB，这导致下行链路和上行链路的系统容量增加了10.5%和11.57%，分别；此外，该算法将呼叫阻塞率降低了38%，端到端延迟降低了5.82%。
