Data Offloading Scheme for 802.11ax WLAN and LTE Heterogeneous Dense Networks
ZHANG Min1，QIAN Chen-xi1，CHEN Qing-hua2
1（School of Computer Science and Technology，Zhejiang University of Technology，Hangzhou 310014，China）2（Department of Information Technology，Wenzhou Polytechnic，Wenzhou 325035，China）
摘要 随着移动设备和无线应用爆炸式增长，蜂窝网络流量迅速增加，许可频段蜂窝网络容量难以满足用户日益增长的数据速率需求.WLAN（Wireless Local Area Network，无线局域网）与LTE（Long Term Evolution，长期演进）蜂窝异构网络中的数据卸载技术能有效缓解蜂窝无线访问的频谱资源紧缺问题.然而，现有LTE-WLAN数据卸载方案并未考虑密集部署问题，也未考虑基于IEEE 802.11ax协议的下一代高效WLAN针对密集部署提出的提速新技术所带来优势.本文利用下一代WLAN的多用户传输特性来缓解蜂窝的资源竞争，通过将部分蜂窝用户卸载到IEEE 802.11ax WLAN网络来保障蜂窝网络的单用户吞吐率.提出的卸载方案建立WLAN和LTE异构密集网络的吞吐率形式化表达式，根据网络系统容量查找蜂窝网络中的最优卸载数，以解决有限的蜂窝网络资源与海量高速业务需求的矛盾.仿真结果表明：在密集部署的异构网络中，所提的方案在保证WLAN用户服务质量的同时，最大限度地提高了LTE网络单用户吞吐率，提升了LTE网络的用户体验.
Abstract：With the explosive growth of mobile devices and wireless applications，the cellular network traffic grows rapidly.It becomes more difficult to meet the increasing data rate requirements of users，since the cellular network capacity of the licensed spectrum is limited.The data offloading technology for the heterogeneous network composed of wireless local area network（WLAN）and long-term evolution（LTE）cellular effectively alleviates the shortage of spectrum resources in cellular network.However，the existing WLAN-LTE data offloading schemes neither consider the problem of dense deployment nor take the advantages of the new technologies proposed in next generation high efficiency WLANs.In this paper，we employ the multi-user transmission introduced in the IEEE 802.11ax based WLAN to alleviate resource competition in cellular network by offloading some cellular users to the next generation WLAN.The proposed offloading scheme firstly establishes the formulations of the throughput in WLAN and LTE dense heterogeneous networks，and then searches for the optimal offloading number in the cellular network subject to the throughput constrain in the WLAN.Simulation results show that the proposed scheme maximizes the single user throughput of the LTE network and improves the user experience of the LTE network while ensuring the quality of service for the WLAN users in dense scenarios.
2021, Vol. 42 
