HVLC: Error correctable hybrid variable length code for image coding in wireless transmission

Abstract

Variable length code (VLC), also called Huffman code [1] is the most popular data compression technique used for solving transmission channel bandwidth bottleneck in image compression standards such as JPEG, MPEG, and H263. But, it is vulnerable to loss of synchronization if they are transmitted consecutively through a noisy wireless channel. It will result in large drops in video transmission quality. We propose a novel Hybrid VLC (HVLC) coding scheme to provide high tolerances to random and burst errors in worsening channel conditions. It exhibits high synchronization, error correction capability and low redundancy. For erroneous HVLC bitstream, it is able to self-synchronize within one codeword. The result shows that it achieves high signal-to-noise ratio (PSNR=30dB) compared to existing VLC schemes at bit error rate (BER) of 10(-3) environment. With efficient memory mapping, HVLC requires low memory spaces and achieves high throughput rate. It is very suitable for VLSI implementation in wireless application.