Abstract: The motivation is to develop better CDMA codes for reducing the hardware complexity of the conventional CP-CDMA. This technology combines the frequency orthogonality of OFDM to CDMA code design for grouping the codes and allows a significant reduction for the calculations in channel equalization. The proposed method is referred to as OFDG code, which divides the codes of M chips in length into N groups, which are orthogonal one another in frequency domain. Each of the groups contains K codes which are mutually orthogonal in time domain. The design principle is introduced and a solution, called CS code, is obtained by the use of two operations to the conventional orthogonal code set; (1) an operation of cyclic repetition and (2) an operation of angle rotation. In comparison with the CP-CDMA, the points taken to channel equalization of CP-CS CDMA can be reduced by a factor of 1/N. The simulation results confirm the effectiveness of this approach.

Key words: CP-CDMA, equalizer, group code, comb spectrum code

摘要： 运用OFDM中的频率正交的概念将CDMA码进行分组，从而大大降低信道均衡的计算复杂度。所建议的正交频率分组（OFDG）码是将长度为M的码集分成N组，任意两组码在频域上相互正交。同一个组内的码在时域上相互正交。文章介绍了这种码的设计准则，并给出了一个具体的实例，称为梳状频谱（CS）码。CS码利用传统的正交码通过2步操作得到：（1）循环重复操作；（2）角度旋转操作。与传统的CP-CDMA相比，CP-CS-CDMA 用于信道均衡的点数减少了N倍。仿真结果验证了这一方法的有效性。

关键词: PRAM, RMESH, 模拟