Soft Mobile Video Broadcast Scheme Based On Real Value

With the popularity of mobile Internet,mobile video traffic is growing dramatically.To improve the utilization of scare wireless bandwidth,video broadcast is proposed to provide video services to multiple users using a single data stream.Considering the processing and features of mobile video broadcast,we investigated soft video broadcast based on real value,and presented a few techniques for optimization.SoftCast performs power allocation over chunks to decrease the amount of meta data.But the magnitudes vary dramatically in some chunks and SoftCast expends very large power to transmit some coefficients with large value.In this paper,scalable video SoftCast using Magnitude Shift is introduced to constraint the value of DCT coefficients.It only costs little power and bandwidth to transmit the overhead generated by Magnitude Shift.However,SoftCast is not efficient when the channel bandwidth is greater than the video bandwidth by retransmission.This paper introduces Analog Channel Coding to utilize the wide bandwidth more efficiently.The transmitted data is divided into two parts:the most important part and the remainder.As the most important part can be estimated correctly at the decoder side,our scheme only transmits the remainder to correct the reconstructed signal.After linear transformation,the energy of the signal is concentrated to a few coefficients.However,the protection of these coefficients is not enough in SoftCast.This paper introduces a component protection to protect these important coefficients to improve the performance.To reduce the overhead generated by component protection,we use hybrid digital-analog modulation to transmit both the analog signal and digital signal.