采用多模Turbo编解码器增加CDMA系统用户容量

Increasing the User Capacity of CDMA Systems by Using the Multi-mode Turbo En-decoder

随着移动用户数量的迅速增加,CDMA系统的容量面临巨大压力。以往Turbo编解码器在CDMA系统中仅用于信道编码,本文则提出采用多模Turbo编解码器增加CDMA系统用户容量。这一方案是基于码分多址与本文提出的Turbo编解码滤波技术。在一个CDMA小区中,基站用K个Turbo编解码器将用户分成K个不同的用户群,每一群的用户可使用小区的全部N个扩频码,采用匹配滤波器组检测同一群内的不同用户。因此,一个小区的用户数量可以增加为原来的K倍。仿真验证该方法是有效的。

With rapid increasing of the number of mobile users, the capacity of CDMA systems is becoming a pressure. The classical Turbo en-decoder is only used to channelen-decoding for CDMA systems. In this paper we used multi-mode Turbo en-decoder to increase the capacity of the CDMA system. The scheme is based on the code division multiple access scheme and the Turbo en-decoding filtering technique presented in this paper.In a CDMA cell, the base station adopts K Turbo en-decoders to divide the mobile users in the cell into K different groups. The N spreading codes of a cell can be assigned to different mobile stations in the K different Turbo en-decoding groups, so the number of users in a CDMA cell can be increased by K times. The bank of matched filters is used to detect user signals in the same Turbo group, so the number of users can be K times of the original . Simulations verify the approach to be effective.