Effective Capacity of Licensed-Assisted Access in Unlicensed Spectrum for 5G: From Theory to Application
Effective Capacity of Licensed-Assisted Access in Unlicensed Spectrum for 5G: From Theory to Application
复制标题
5G 非授权频谱授权辅助接入的有效容量：从理论到应用
DOI：
10.1109/jsac.2017.2710023
复制
发表时间：
2017-08-01
影响因子：
16.4
通讯作者：
Liu, Ren Ping
中科院分区：
文献类型：
--
作者：
Cui, Qimei;Gu, Yu;Liu, Ren Ping
许可辅助接入（LAA）是一种有前途的技术，用于将急剧增加的蜂窝业务卸载到未许可频带。由于LAA和传统系统（如Wi-Fi）在频带中共存的分布式和异构性，服务质量（QoS）和容量量化的提供带来了挑战。在本文中，我们开发了新的理论的有效容量来衡量LAA统计QoS要求。一个新的四状态半马尔可夫模型的开发，以捕捉传输冲突，随机退避，和有损无线信道的LAA在分布式异构网络环境中。推导了有效容量的封闭表达式，对LAA进行了综合分析。四状态模型被进一步抽象为一个有见地的两个状态的等效，揭示了在传输速率方面的有效容量的平方。通过仿真验证，该方法可以最大限度地提高LAA的有效容量和有效能效，与现有方法相比，分别提高了62.7%和171.4%。研究结果对LAA系统的整体设计和部署具有一定的实用价值。
License-assisted access (LAA) is a promising technology to offload dramatically increasing cellular traffic to unlicensed bands. Challenges arise from the provision of quality-of-service (QoS) and the quantification of capacity, due to the distributed and heterogeneous nature of LAA and legacy systems (such as Wi-Fi) coexisting in the bands. In this paper, we develop new theories of the effective capacity to measure LAA under statistical QoS requirements. A new four-state semi-Markovian model is developed to capture transmission collisions, random backoffs, and lossy wireless channels of LAA in distributed heterogeneous network environments. A closed-form expression for the effective capacity is derived to comprehensively analyze LAA. The four-state model is further abstracted to an insightful two-state equivalent which reveals the concavity of the effective capacity in terms of transmit rate. Validated by simulations, the concavity is exploited to maximize the effective capacity and effective energy efficiency of LAA, and provide significant improvements of 62.7% and 171.4%, respectively, over existing approaches. Our results are of practical value to holistic designs and deployments of LAA systems.