The inhibition effect of bridge function smart code on multipath interference and multiple access interference in cognitive radio system

This paper proposes an UWB cognitive radio system using bridge function smart code sequence as the spread spectrum sequence. The bridge function smart code sequence's auto-correlation function contains the zero correlation zones which can reduce multipath fading interference (MPI).The smart code sequence which is generated in a special way with a nature that its cross-correlation function is identically zero. It can significantly reduce the multiple access interference (MAI) in the multi-user system. The result shows the UWB cognitive radio system using the bridge function smart code with a better performance on avoiding MPI and MAI than one using other spread spectrum sequences without zero correlation zones.