Performance evaluation of a two dimensional spread spectrum system in Rician fading channel

In this paper, a novel digital modulation technique called column-orthogonal two dimensions spread spectrum technique (2DSS) is analyzed. With 2DSS, each data symbol is firstly spread by a spreading code, and then each chip is transmitted at multiple subcarriers with each subcarrier modulated by ´1´ and ´1´ based on other spreading code, which is changing with the order of chip in the data symbol. Analytical results are presented on the performance of this multicarrier multiple access schemes in the downlink of an indoor wireless Rician fading channel with an additive white Gaussian noise. A closed-form expression of the bit error rate performance of this communication system is derived. Numerical result of the performance of this 2DSS multicarrier system shows its advantage in low signal noise ratio. Meanwhile a comparison is made with the MC-CDMA system in the same fading channel.