Abstrakt

Using Interleaving Techniques with FEC Mechanisms to Deal with Burst Errors

M.SangeethaPriya, C.Devipriya, Dr. N.Saravana selvam

Forward Error Correction (FEC) is one of the most common means of performing packet error recovery in data transmissions. FEC schemes typically tune the FEC rate in accordance with feedback information provided by the receiver. However, the feedback and FEC rate calculation processes inevitably have a finite duration, and thus the FEC rate implemented at the sender may not accurately reflect the current state of the network. An Enhanced Random Early Detection Forward Error Correction (ERED-FEC) mechanism to improve the quality of video transmissions over Wireless Local Area Networks (WLANs) is utilized. The FEC redundancy rate is calculated directly at the Access Point (AP). Moreover, the redundancy rate is tuned in accordance with both the wireless channel condition (as indicated by the number of packet retransmissions) and the network traffic load (as indicated by the AP queue length). The experimental results show that the proposed ERED-FEC mechanism achieves a significant improvement in the video quality compared to existing FEC schemes without introducing an excessive number of redundant packets into the network. The channel seen by applications is the physical channel as modified by the error correcting mechanisms used at the physical level. The residual error process is to be considered and the block error process beyond the marginal statistics has to be considered. A Markovian model for the block errors can be used and can be shown adequate.