Research On Cross-Layer Content-Aware Scheduling Algorithm In Wireless Video Communication System

In recent years,video communication service in wireless communication system has been popular among people because of its vivid and picturesque characteristic.Especially,LTE network can support bandwidth of 20MHz,which provides the development of video service more viable prospect.In time-varying and fading wireless channel,the video packets cannot be received by decoder before their deadline,so they are discarded by decoder,which not only wastes precious bandwidth,but also causes degradation of video quality.So it is important to adopt efficient resource allocation and packet scheduling scheme to make packets discarding have least influences on video reconstructed quality at the receiver and thus improve users'video quality.Firstly,video transmission distortion in wireless channel is discussed.The simulation results show that transmission distortion estimated by paper is approximated to the real distortion.Then a modified content-aware proportional fair scheduling scheme is presented based on the principal of cross-layer designation.This scheme considers transmission distortion and delay of video packet and channel quality when designing the priority of users,especially the delay parameters is different among different video frame type.Then,the users to be served is allocated with appropriate subchannel by making full use of multiuser diversity. Simulation results show that the average PSNR of reconstructed video at the receiver is improved about 1.0894 dB while comparing the proposed scheduling scheme to the conventional proportional fair algorithm.Therefore,the proposed scheduling algorithm can improve the video quality of user efficiently.Finally,existing limited feedback algorithm is improved and is then applied in video scheduling strategy in LTE system.The number of channels fed back to the base station is decided by the number of resource block.At the same time,the worst subchannel should also be fed back.Via simulation,we can see that compared to scheduling algorithm with full bandwidth feedback,scheduling algorithm with limited feedback losses less video quality and reduces feedback load greatly.