Research On Channel Access And Scheduling Mechanism Of LAA

The rapid growth of mobile Internet leads to increased pressure on the 4G network operating in the licensed spectrum. In order to seek effective means of shunt, 3GPP started the LAA (Licensed Assisted Access using LTE) study item in 2014. LAA is a solution to improving network capacity with low cost and high performance. LAA works on the unlicensed spectrum where lies a variety of regulatory requirements, faced with the challenge to coexist with WiFi friendly. LAA expands the available bandwidth by using carrier aggregation between the licensed spectrum and the unlicensed spectrum. The licensed spectrum can be used to guarantee coverage and provide data service with high reliability and low latency. The unlicensed spectrum can be used to provide hotspot enhancement and data distribution. LAA will improve the network capacity effectively and provide better user experience.LAA works on the unlicensed spectrum where lies a variety of regulatory requirements, faced with the challenge to coexist with WiFi friendly. The main topic of this paper includes channel access mechanism, uplink scheduling scheme and other related contents.In this paper, we firstly introduce the key technologies of LTE-A system and WiFi system briefly and summarize the functional requirements of the LAA system. Then we discuss various channel access technologies including LBT(Listen Before Talk). We design an efficient mechanism to adjust the contention window by selecting various feedback information from user side, in which way we improve the LBT mechanism based on variable contention window. By making use of different carriers for uplink scheduling signaling, we design two kinds of scheduling mechanism for uplink scheduling including self-carrier scheduling and cross-carrier scheduling. After that, we build a system-level simulation platform and develop some key modules including the module for sharing channel occupancy information suitable for multi system scenarios. At last, we evaluate multiple channel access mechanisms and scheduling schemes,based on which several conclusions have been drawn.