Optimization of Unequal Error Protection Rateless Codes for Multimedia Multicasting
This work addresses multimedia multicasting efficiency for heterogeneous users, but it is incremental as it builds on existing rateless code methods.
The paper tackles the problem of optimizing rateless codes for unequal error protection in multimedia multicasting to heterogeneous users, showing that the proposed coder achieves favorable performance compared to other recent UEP rateless codes.
Rateless codes have been shown to be able to provide greater flexibility and efficiency than fixed-rate codes for multicast applications. In the following, we optimize rateless codes for unequal error protection (UEP) for multimedia multicasting to a set of heterogeneous users. The proposed designs have the objectives of providing either guaranteed or best-effort quality of service (QoS). A randomly interleaved rateless encoder is proposed whereby users only need to decode symbols up to their own QoS level. The proposed coder is optimized based on measured transmission properties of standardized raptor codes over wireless channels. It is shown that a guaranteed QoS problem formulation can be transformed into a convex optimization problem, yielding a globally optimal solution. Numerical results demonstrate that the proposed optimized random interleaved UEP rateless coder's performance compares favorably with that of other recently proposed UEP rateless codes.