Research On Qo S Control Of Home Video Transmission Based On PLC

With the development of information technology,the environment of smart home which is safe,comfortable and efficient has become the trend of people's lifestyles,so the application of video surveillance technology in the smart home security system has gradually become popular.Due to the factor of the high cost,strong radiation,weak control and complex in installation in the traditional form,the development of video monitoring system of smart home is affected.So the rise of power line carrier communication technology makes up for the traditional communication technology problems.Power line technology uses the existing power line to transfer the video data without laying data lines,makes the best of resources and reduces the construction cost.At the same time as the power line carrier module with high integration technology which has the small occupied volume in the family,it is almost not affected by geographical environment and convenient to be installed.Therefore in the existing video monitoring system of smart home,it combines wireless communication technology and power line carrier communication technology to achieve the higher practical value and open up the wide application market.In this paper,the main research areas are power line carrier communication technology and wireless communication technology.At first the paper analyses the characteristics of the power line carrier data transmission system such as the ASK,FSK,PSK modulation technology and the popular modulation technology which are the spread spectrum communication technology and OFDM communication technology.It draws a conclusion that OFDM communication technology is more suitable in the high speed power line communication.Then the paper analyzes the characteristics of the power line channel and noise model,and combines with the OFDM baseband model to present a pulse suppression iterative algorithm based on convolutional codes.The algorithm uses the excellent error correction performance of convolutional codes and adaptive threshold to overcome the impact of impulse.The experimental part uses distribution model of Poisson to mix the impulse noise and additive white Gauss noise as the total the system simulation environment,and verify the algorithm can effectively reduce the error rate and improve the signal-to-noise ratio of the system.According to the serious packet loss phenomenon of using the UDP protocol to transfer video data in power line,the paper proposes an adaptive rate control method based on the terminal by RTP/RTCP protocol in the wireless network.By controlling the smoothing parameter of packets loss rate and the thresholds of packets loss rate and delay jitter to ensure the regulation principle as rising slowly and dropping fast.Finally,the feasibility of the algorithm is verified by the observation curve of packets loss rate and the video quality.