In this paper, basing on the code division multiple access (CDMA) technology, we proposed a new modified implementation of transform domain communication system (TDCS), which is great potential to be applied in the cognitive radio (CR) contexts. Compared with the traditional TDCS, the complex RAKE receiver is avoided in our proposal. The performance of this CDMA-based TDCS is investigated and discussed through theoretical analyses and simulation in Additive White Gaussian Noise (AWGN) and multi-path fading channels. Computer simulation results show that the CDMA-based TDCS is much more superior than the traditional TDCS and can be a promising transmission scheme in CR contexts.