Research And Implementation Of Multi-screen Sharing System Based On WiFi Display

With the rapid growth of the number of mobile intelligent terminals,a variety of wireless video streaming applications flourish,and wireless screen mirroring is one of the important components.Wireless screen mirroring can project the content of small screen to big screen for share using WiFi connection.The device with original support for wireless screen mirroring is still not popular,so auxiliary multi-screen sharing system is needed to solve the problem.The WiFi environment has the characteristics of limited bandwidth and time-varying wireless channel.The mobility of the smart terminal will lead to the fluctuation of the actual transmission rate of the WiFi.The WiFi transmission of the streaming media will also be affected by the same and adjacent frequency interference.The above factors will affect the user experience of wireless screen mirroring.In this paper,the theory of WiFi Display protocol is analyzed first,and then a multi-screen sharing system is implemented by using RTL8188 CUS wireless network card and Allwinner A20 processor development environment.The test results show that the feasibility of the design scheme.To guarantee the QoS of wireless screen mirroring application,this paper proposes a frame dropping control algorithm and two frame dropping strategies based on packet virtual transmission time estimation in WFD Source MAC layer transmit queue.The proposed algorithm is implemented in improved myEvalSVC simulation framework.Several simulation experiments is designed.And the experimental results show that in various WiFi network congestion scenarios,the proposed algorithm outperforms traditional MAC queue algorithm droptail in IEEE 802.11 protocol and can effectively control and reduce the wireless screen mirroring end-to-end delay and improve the PSNR.