Research And Implementation On Key Techniques Of Error-tolerant Receiving Of Wireless Streaming Media Data

Wireless streaming data is easy to introduce errors during transmission due to the high error rate of the wireless channel,resulting in packets with errors can not be checked and discarded.Typical error control method based on retransmission mechanism is not suitable for delay constrained higher real-time streaming media business.In order to improve the quality of streaming media services,in this paper,from the perspective of improving the utilization of network data,the error-tolerant receiving technology of streaming media data is studied.The research is surrounded around the error-tolerant recognition and error-tolerant reassembly of the streaming media data.The main achievements and innovation points are as follows:1.The format of streaming media data packet is analyzed in detail,and the critical control fields which are important for recognition and reassembly of streaming media data are determined.And an error-tolerant receiving protocol stack model and a critical control field repair model are constructed.These studies are the basis of the error-tolerant recognition and error-tolerant reassembly of the streaming media data.2.In view of the error-tolerant recognition of streaming media data,an error-tolerant recognition algorithm for RTP data based flow identification field recovery is proposed.Based on the statistical analysis of the correct RTP data,the prior information of the critical control field is obtained,and the error critical control field is repaired according to the maximum a posteriori(MAP);Based on above,the error-tolerant recognition algorithm for RTP data is designed.Simulation results show that,compared with existing methods,the proposed algorithm can improve the recall rate of RTP data significantly.3.In view of the error-tolerant reassembly of streaming media data,an error-tolerant reassembly algorithm for RTP data based on sequence number field recovery is proposed.Through analysis of the cross-layer constraint relationship between protocol fields,using the constraint among sequence number field with identification field and timestamp field to determine the possible locations of the wrong data packet.By analyzing the change rules of sequence number field,the possible range of the error sequence number is determined,and error sequence number is repaired according to the minimum distance criterion.Based on above,an error-tolerant reassembly algorithm for RTP data is designed.Simulation results show that the proposed algorithm can reduce the error rate of sequence number,and improve the ability of data reassembly.4.The core modules of wireless streaming media data error-tolerant receiving and processing software are designed and implemented.The modules not only can dispose streaming media data based on RTP protocol,but also has the repair function of UDP flow identification.The test results demonstrate that the software can effectively improve the utilization of streaming media data.