This document summarizes a range of possible techniques for the repair of continuous media streams subject to packet loss. The techniques discussed include redundant transmission, retransmission, interleaving and forward error correction. The range of applicability of these techniques is noted, together with the protocol requirements and dependencies.

where p(t) is a (typically real valued) pulse shape, and the ck are QAM symbols drawn from a finite collection of complex numbers called a constellation based on input bits to be communicated over the channel. Some example QAM constellations include 4-QAM (a.k.a QPSK){±1± j}, 16-QAM {±a± jb} with a, b ∈ {1, 3}, 64-QAM {±a + jb} with a, b ∈ {1, 3, 5, 7}, and 256-QAM {±a ± jb} with a, b ∈ {1, 3, ...

Motivated from the theory of quantum error correcting codes, we investigate a combinatorial problem that involves a symmetric n-vertices colourable graph and a group of operations (colouring rules) on the graph: find the minimum sequence of operations that maps between two given graph colourings. We provide an explicit algorithm for computing the solution of our problem, which in turn is direct...

In a recent paper Calderbank, Rains, Shor and Sloane [1] described a method of constructing quantum-error-correcting codes from ordinary binary or quaternary codes that are selforthogonal with respect to a certain inner product. We use this relation to show that a class of binary formally self-dual codes defined by symmetric matrices give rise to quantum codes with error-correcting capacity pro...