Redundant codes in hybrid networks

Hybrid networks consisting of satellite links and mobile ad hoc networks present a series of challenges due to different packet-loss patterns, delay, and, usually, scarce available bandwidth. In this scenario, redundant encoding, in the form of Forward Erasure Correction (FZC) codes can provide an effective protection against losses in multicast videoconferencing and video streaming applications. The obtained experimental measurements show the performance of FZC codes based on Vandermonde matrix, for multicast video streaming applications. The performance evaluation has been based both on subjective perception of QoS and on objective parameters of QoS. The used subjective assessment has been the perceptual quality, called the Mean Opinion Score (MOS). The reference measure used for an objective video quality assessment has been the Peak Signal to Noise Ratio (PSNR), calculated on the difference signal between the original error-free sequence and the received decoded sequence. Other general objective parameters of QoS, such as packet delivery delay and packet loss, have been considered. Numerical results are presented.