The effects of zero padding on the CDPD wide-area IVHS data load

This paper analyzes the effects of zero padding in Cellular Digital Packet Data (CDPD) on the wide-area intelligent vehicle highway systems (IVHS) data loads for a typical metropolitan area. Zero padding occurs to prevent the occurrence of flag or abort sequences of bits within a frame. Although the padding seems a priori to be negligible (approximately 1.6% additional bits on average), its impact needs to be properly assessed due to the quantization in the radio channel (physical layer) into Reed-Solomon (RS)-blocks. As a frame of reference, we evaluate what is the actual increase in the CDPD data load that can be ascribed to zero padding for the modelled metropolitan area