M-ary Code-Selected DS-BPAM UWB System with SRake Receiver over Multipath Channels

In this paper, we consider an M-ary code selected direct sequence bipolar pulse amplitude modulation (MCSDS-BPAM) ultra wideband system. The system performance and analysis over realistic IEEE UWB multipath fading channels are evaluated in the condition of perfect time synchronization and selective diversity combining Rake (SRake) receiver. In the transmitter, a particular DS code sequence can be selected by the log2(M/2) bits from the DS code set. The corresponding SRake receiver structure is designed according to the transmitter. This scheme can improve the system performance and increase the data rate by a factor log2(M/2) compared with the conventional DS-BPAM UWB system. With the increase of the modulation level M and the SRake fingers, the system performance can be improved for the same signal energy per bit.