An Interference Avoidance Code Assignment Strategy for Downlink Multi-Rate MC-DS-CDMA with TF-Domain Spreading

Li-Chun Wang, Chih-Wen Chang, Howard Huang
2007 IEEE Transactions on Wireless Communications  
Frequency selective fading may affect the orthogonality of the spreading codes in the multi-carrier direct sequence code division multiple access (MC-DS-CDMA) systems. In this paper, we define a new performance metric called the multiple access interference (MAI) coefficient for the MC-DS-CDMA system to quantitatively predict the impact of inter-code interference with the time-and frequency-domain spreading in a frequency selective fading channel. With the help of MAI coefficient, a novel
more » ... ient, a novel interference avoidance code assignment strategy is proposed. By jointly considering the incurred MAI effect and the blocking probability in the code tree structure, the proposed interference avoidance code assignment method can effectively reduce the MAI for the multi-rate MC-DS-CDMA system, while maintaining very good call blocking rate performance. Index Terms-Code assignment, interference avoidance, MAI coefficient, MC-DS-CDMA.
doi:10.1109/twc.2007.05888 fatcat:5dkb4h75qjef7jybdnyubfna6i