[Paper] A Novel Multicarrier CDMA Scheme With Interference Free Performance in Very Large Delay Spread

Abstract

A wireless communication technology that allows multiple users to communicate in real time is strongly required to support various needs such as high performance remote control systems to simultaneously move many mobile units like robots and vehicles and wireless network systems to dynamically link mobile units. This paper proposes a new multicarrier code division multiple access (MC-CDMA) scheme without the multiple access interference (MAI) and inter carrier interference (ICI) over a very large delay spread channel, which can be characterized by a block coding technique using a set of sequences with a zero correlation zone (ZCZ code) and a minimum mean square error (MMSE) RAKE receiver utilizing the pilot sequence for channel estimation to remove MAI and ICI and to reduce the influence of the inter symbol interference (ISI), respectively. It does not need a frequency domain equalization technique which has been used in multicarrier communications. The length of delay spread is related to only block size and does not depend on the size of the zero correlation zone and the number of users. In various parameters including an effective ZCZ code, the improved bit error rate (BER) performance of the proposed scheme is demonstrated by computer simulation.