Forward error correction decoding for WiMAX and 3GPP LTE modems

Abstract

In this paper, we review the requirements for forward error correction (FEC) decoding for next generation wireless modems-mobile Worldwide Interoperability for Microwave Access (WiMAX) and third generation partnership project long term evolution (3GPP LTE). FEC decoder consists of mainly three components: control channel decoder, data channel decoder, and hybrid automatic repeat query (HARQ) combining. Control channel decoder is constrained by latency budget which impacts buffering as well as power management of modem signal processing chains. For WiMAX, both Viterbi and Turbo decoders are required to receive control channel while for LTE, only Viterbi decoder is required. For data-channel, a high-throughput Turbo decoder is required to support high data rate. HARQ combining is mainly dominated by memory size and bandwidth requirements given the maximum data rate, maximum number of HARQ processes and re-transmission formats. We analyze the requirements and discuss possible candidate architectures for three components.