A Comparison of Multi-Carrier OFDM and Single Carrier Iterative Equalisation for Future High Performance Wireless Local Area Networks

There has been a strong trend towards the specification of multi-carrier Coded Orthogonal Frequency Division Multiplexing (COFDM) in the physical layer of emerging high performance Wireless Local Area Networks (WLAN). This trend is based on an alleged combination of enhanced performance and lower terminal complexity. However, in recent years significant advances have been made in the field of single carrier equalisation, where iterative equalisation and decoding now offers excellent error rate performance in slow and fast fading channels. This paper investigates the possibility of employing a single carrier system using iterative equalisation at the receiver as a direct competitor to multi-carrier COFDM. The throughput, range and terminal complexities of a COFDM solution are compared with those of a single carrier iterative equalised approach for identical indoor channel conditions. The paper demonstrates that iterative equalisation outperforms COFDM in an indoor environment. However, from a cost/performance viewpoint, COFDM is still seen as the more attractive solution. Keywords-Iterative Equalisation, Orthogonal Frequency Division Multiplexing, Turbo Coding