Coding and Resource Scheduling in Packet Oriented Adaptive TDMA/OFDMA Systems

Abstract

adaptive transmission is investigated as a key technology for boosting the spectral efficiency of a new radio interface for 4G systems. Adaptive allocation and link adaptation of timefrequency chunks based on channel prediction in an OFDMbased system offers a significant potential to design a spectrally efficient system. The chunk size is typically defined based on the minimum coherence time and coherence bandwidth of the targeted channels. It is important to allow efficient channel coding and link retransmission schemes without restricting the resource scheduler, even for systems using small chunk sizes, to achieve multi-user diversity gains. In this paper we introduce some possible approaches to implement FEC coding and Hybrid ARQ and analyze their interplay with resource scheduling in packet oriented adaptive TDMA/OFDMA. Index Terms-4G mobile wireless systems, adaptive transmission and multiple access, Orthogonal Frequency Division Multiplexing (OFDM), forward error correction coding (FEC), link retransmissions, spectral efficiency. I.