Error correction coding for serial-tone HF transmission

Convolutional and Reed-Solomon (RS) codes are often considered when choosing a forward error correction (FEC) scheme for use in the HF environment. Each code has its advantages: soft decision decoding with convolutional codes, and superior burst error resistance in the case of RS codes. Although there are arguments in favour of each code, there appears to have been little work comparing the performance of convolutional and RS codes employed with serial-tone modems for HF channels. The advantages and disadvantages of each coding scheme are highlighted through a series of tests over simulated HF channels. The comparison includes RS codes using erasures decoding and nontraditional RS symbol formation. As well as comparing the performance of convolutional and RS codes, concatenated codes formed by using a convolutional inner code and RS outer code are also examined.