Index Mapping for Bit-error Resilient Multiple Description Lattice Vector Quantizer

This work addresses the construction of bit-error resilient multiple description lattice vector quantizers (MDLVQ) by proposing the design of a structured mapping gamma of side lattice points to binary indexes. We assume that the first description is correct while the second description may carry bit errors. To design the mapping gamma the set of side lattice points is first partitioned into Voronoi regions of an appropriate coarse lattice. Next a good channel code C is selected, each Voronoi region is assigned a coset of this channel code and the side lattice points within each Voronoi region are mapped to binary sequences in the corresponding coset. We derive a lower bound on the error correction performance of the mapping gamma in terms of the performance of the code C and we show that, as the rate of the MDLVQ grows to infinity, the mapping gamma becomes as good as the code C. Simulation results show the significant superiority of the proposed mapping versus random mappings.