Packet loss protection of embedded data with fast local search

Abstract

Unequal loss protection with systematic Reed-Solomon codes allows reliable transmission of embedded multimedia over packet erasure channels. The design of a fast algorithm with low memory requirements for the computation of an unequal loss protection solution is essential in real-time systems. Because the determination of an optimal solution is time-consuming, fast suboptimal solutions have been used. In this paper, we present a fast iterative improvement algorithm with negligible memory requirements. Experimental results for the JPEG2000, 2D, and 3D set partitioning in hierarchical trees (SPIHT) coders showed that our algorithm provided close to optimal peak signal-to-noise ratio (PSNR) performance, while its time complexity was significantly lower than that of all previously proposed algorithms

Joint product code optimization for scalable multimedia transmission over wireless channels

“…One may accelerate this approach by replacing the Lagrange-based algorithm with a faster algorithm. For example, our iterative improvement algorithm [10] computes a near-optimal RS protection, and its complexity is much lower than that of all previous algorithms. This algorithm works as follows.…”

“…When the convexity assumption of φ is severely violated, it may be advantageous to determine our local search solution by using a piecewise affine approximation of φ (see [10]). …”

“…We propose therefore to start with the rate-optimal RS protection that gives the largest expected rate and try to improve the associated product code by progressively increasing the number of protection symbols. This is done by alternately applying the local search algorithm of [10] and decreasing the RCPC code rate. We also exploit the fact that if S is our current RS protection, then one can exclude all RCPC code rates for which the lower bound of Proposition 1 (i) is greater than E[d](S).…”

“…Let r k n+1 be the highest code rate in Rn+1. Apply the iterative improvement algorithm of [10] to the child of S kn in F k n+1 . This gives a solution…”

“…The local search algorithm of [10] first computes a rateoptimal protection. This is straightforward because…”