Research On TD-LTE Radio Resource Management Based On Cognitive Radio

The development of broadband wireless access technology and demand of highdata rate prompted3GPP to propose LTE at the end of2004and promote itsdevelopment.TD-LTE as the standard for LTE TDD system is communicationtechnology standard proposed by China, which has the advantages of flexibleconfiguration system frequency, the effective use of scattered bands, and high spectralefficiency. With the TD-LTE network carried out and deployed, TD-LTE encounteredthe threshold of spectrum resource constraint. The demand of data rate brings theproblems of complicated same frequency interference and difficult resource allocationto TD-LTE. So more spectrum is an effective measure to solve these problems, but thefixed spectrum allocation policy leads to the limited spectrum which can be assignedto LTE.Cognitive Radio is a solution to the shortage of spectrum resources and spectrumutilization rate in wireless networks, achieving the goal of spectrum sharing amongmulti-users and improving spectrum resource utilization. By introducing CRtechnology into TD-LTE, it can make use of UHF band to expand the spectrum rangeand flexibility of TD-LTE for the requirements of high data rate and broadband. Dueto the dynamic nature of idle spectrum and protection of primary users, it needs toperform switch handover to avoid causing interference to primary uses when primaryusers appears, which put forward higher requirements in radio resource managementof TD-LTE.This paper focuses on quiet period configuration and resource scheduling inTD-LTE RRM based on cognitive radio. Firstly it introduces the development ofTD-LTE system and characteristics of cognitive radio technology, and deploymentscenario of TD-LTE system with cognitive radio. It researches on the problems ofquiet period and scheduling and presents corresponding solutions:1.proposed amechanism of quiet period, whose idea is to perform spectrum detection dynamicallyaccording to urgency of different kinds of spectrum and cell load in order to reducethe number of spectrum detection;2.propesed a scheduling algorithm based on switchuser’s QoS for the process of spectrum handoff, which makes use of the change ofcognitive users’ number to adjust the priority calculation to ensure the users’ QoS.3.built a system level simulation platform, the network initialization module inthe platform completes the initialization of system according to configurationparameters, physical layer module simulates the channel model in macro cell andcalculates SINR provided to L2S module;L2S module calculates an equivalent SINRaccording to the SINR of subcarriers to get BLER which used by upper modules;resources scheduling module finishes the allocation of resources; service modulemanages the data of users in the process of simulation and saves the results. By thesimulation of scheduling, the simulation results show that the proposed algorithmachieves better QoS performance.