Efficient synchronization and power control processes for up-link multicarrier systems based on MC-CDMA technique

In this paper, a new synchronization and power control process for up‐link (UL) multicarrier systems based on MC‐CDMA technique is presented. The main challenge for multicarrier systems is the time synchronization of several users who transmit data on the same OFDM symbol by using OFDMA or MC‐CDMA techniques. The aim of the UL synchronization process is to apply a global and unique fast fourier transform (FFT) to determine the data information of all users at the base station (BS). In order to allow this unique operation, estimation and correction of all the propagation delays between each user and the BS are required. This paper presents the principles of this ranging method based on the MC‐CDMA technique and the new algorithm processed at the reception side. This new algorithm is based on the differential demodulation technique and is compared to classical correlation methods applied either in the frequency or in the temporal domain in terms of performance and complexity. Copyright © 2004 AEI