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Research On Vertical Handover Algorithm In Indoor VLC/Wi-Fi Wireless Heterogeneous Network

Posted on:2022-10-17Degree:MasterType:Thesis
Country:ChinaCandidate:C X MaFull Text:PDF
GTID:2518306512971549Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
With the rapid increase in wireless terminal devices such as smartphones,tablets,and smart watches,the increasingly mature VR technology,the smart homes,and the exponential growth of network demand serv ices,the radio frequency transmission technology with scarce spectrum resources is facing huge challenges.80%of the wireless network traffic comes from indoors,and a heterogeneous network can be formed by diversified spectrum resources to provide high-quality services for user terminals.The indoor high-speed visible light communication technology has advantages of being less susceptible to electromagnetic interference,safe and confidential,not endangering human eye and light signals cannot penetrate walls.In indoor wireless networks,it can provide another high-speed and flexible access method that connected to Wi-Fi and cellular networks.According to the characteristics of VLC/Wi-Fi wireless heterogeneous networks,in order to meet business needs users must switch during different networks.Therefore,it is important to study the choice of user access points in V LC/Wi-Fi heterogeneous networks.The main work and research results are as follows:(1)Cumulative distribution function of rate.First,the statistical expressions of the rate are derived to analyze the performance,these statistical expressions are used to obtain the closed expression of outage probability in the hybrid VLC/Wi-Fi heterogeneous network,finally,the simulation results show that is used to analyze influence of parameters between the bandwidth and the distance of user and access point.The simulation results show that the wider the bandwidth and the closer the distance between user and access point,the lower the outage probab ility.(2)A vertical handover algorithm that meets user rate.In the VLC/Wi-Fi heterogeneous network,the types of user services increase,and difTerent service requirements have different requirements for network service parameters,so users can access the appropriate network according to own rate.First,the vertical handover standard is use rate.then between the user rate and the set threshold are compared,finally,trigger the vertical handover according to the comparison result of the two rates.The simulation results show that compared with the equivalent SINR and VLC priority algorithm,users of the rate requirements algorithm obtain a higher rate and lower outage probability during the movement.The transmission rate varies with LED power,FOV and noise intensity and the simulation results show that user in the rate of requirements algorithm obtains a high transmission rate.(3)Vertical handover algorithm based on cost function.In the VLC/Wi-Fi heterogeneous network,the rate decreases with increase of the user number,the number of times users switch network to meet own needs increases.Therefore,an algorithm to reduce the number of handover is improved.First,the user detects the available network,and the central unit needs to calculate the cost function of the network SINR and rate.Secondly,it compares the calculated comprehensive cost function value with the cost hysteresis as the vertical handover standard.Finally,the time hysteresis is set to reduce the number of user handovers.The simulation results show that compared with the equivalent SINR,the cost function algorithm can reduce the number of handovers and the ping-pong effect effectively,and increase the channel capacity to have better service experience.
Keywords/Search Tags:Visible Light Communication, Wireless Heterogeneous Network, Vertical Handover, Rate of Requirement, Cost Function, Time Lag
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