Channel estimation of uplink for MC-CDMA systems

Multi-carrier code division multiple access system (MC-CDMA) is a flexible and adaptable radio interface to provide dynamically changing bit rates and a variety of services on radio channels. An accurate channel estimate allows the use of multi-user detection and power loading to improve system performance. In this paper, we propose a novel channel estimation method of uplink for MC-CDNU systems. In MC-CDMA systems, code-multiplexed pilot symbols are transmitted consecutively in both time and frequency domains. In the proposed method, weighted pilot symbols in both domains are coherently added to improve signal to noise ratio of pilot symbols in channel estimation. We propose a method to select the weighting factor for pilot symbols according to the changes of propagation by measuring the maximum Doppler shift and the maximum delay time. Also the channel estimation algorithm is simplified. The method is evaluated in the end. The results show that the method is simple and effective.