Performance of punctured channel codes with ARQ for multimedia transmission in Rayleigh fading channels

摘要

The transmission of different multimedia source data requires different levels of error protection. Punctured convolutional codes in conjunction with automatic repeat request (ARQ) schemes, such as the ones used in type II hybrid and type III ARQ schemes, can enable the transmission of varying redundancy to provide different levels of error protection for different data packet. However, the performance of these codes with ARQ in Rayleigh fading environments are not well understood. We designed two systems based on type II hybrid and type III ARQ schemes. We studied extensively their performances in different Rayleigh fading environments and with different system parameters. We showed that in fast fading environments, type II hybrid and type III ARQ schemes achieves better throughput than the simple ARQ scheme without coding. However, convolutional codes do not work well in slow fading environments. Thus, in a slow fading environment simple ARQ scheme without coding achieves better throughput compared to that of type II hybrid and type III ARQ schemes at relatively low SNR when the transmission packet size is small. However, when the transmission packet size is large, simple ARQ scheme performs poorly and it may be advantageous to use type II hybrid and type III ARQ scheme even in relatively slow fading environments. To take full advantage of punctured convolutional codes to provide for different levels of error protection in a slow fading environment, one may employ techniques such as transmit antenna diversity technique to simulate a fast fading environment.