广播网络中基于补丁流的丢包恢复机制研究

现有的数字广播网络由于没有回传通道，发送端无法知悉传输过程中的丢包状况。接收端处在广播网络的不同位置，常常因处于小区边缘或受障碍物遮挡等原因造成信号减弱，从而导致丢包率提高。该文提出了一种基于pFEC (patching Forward Error Correction，补丁FEC)的丢包恢复机制，来解决单向广播网络的丢包问题。该方法利用蜂窝移动网络的双向信道来传输补丁流，提供自适应的FEC来降低丢包率。这种方式可以在广播业务中为不同位置的用户提供不同的丢包恢复能力。理论建模及仿真结果显示，在蜂窝移动网络丢包率不高的情况下，pFEC机制能够有效应对个别用户突发的丢包，从而提高广播业务整体的可靠性和服务质量。

Research on Mechanism of Packet Loss Recovery Using Patching FEC in Broadcasting Networks

As the broadcasting networks have no feed back channel, the sender has no idea about the packets loss during the packets are transmitted. Signals may reduce and the Probability of Packet Loss (PPL) increases, when the terminals are on the edge of the cell or blocked by some buildings. A patching Forward Error Correction (pFEC) mechanism is proposed to provide low PPL in broadcasting networks. The mobile networks are used as the return channel to get the information of PPL, and the redundancy packets are transmitted via mobile networks for reducing the PPL. This mechanism provides the different packet loss recovery ability for different people according to the reports from receivers. The simulation results show that if the mobile networks are in a low PPL condition, the pFEC mechanism will have a good performance in decreasing the PPL, and improves the reliability and quality of service.