A Combination of CS-CDMA and OFDM for Enhanced LTE on Downlink Channel

作者：Jiao Bingli^*; Ma Meng; Lee William C Y

来源：Journal of Communications and Networks, 2013, 15(1): 8-14.

DOI：10.1109/JCN.2013.000004

• Cellular system
• code division multiple access (CDMA)
• frequency reuse
• orthogonal frequency division multiplexing (OFDM)

For alleviating the low spectrum efficiency problem of orthogonal frequency division multiplexing (OFDM), due to the strong inter-cell-interference (ICI) at cell's edge, we introduce comb-spectrum code division multiple access (CS-CDMA) into broadband OFDM system at downlink channel for enabling the use of entire spectrum for seamless coverage. In addition, we develop a new method, called orthogonal cell code (OCC) scheme, to assist CS-CDMA for nullifying the ICI from contiguous cells. In system operation, each of the conventional cells is divided into an outer cell and an inner cell, and a mobile station (MS) should access to the CS-CDMA when it is in the outer cell and access to OFDM when it is in the inner cell. This study investigates the spectrum efficiency of using CS-CDMA and makes a comparison with that of long term evolution (LTE) in the following cases; (1) under an assumption of perfect channel state information and (2) based on channel estimates at a MS station. The results show the great advantage of utilizing the proposed system.

• 出版日期2013-2
• 单位北京大学