Spectrum efficiency of a TDMA/W-CDMA frequency sharing system with notch filters and signal clippers

In this article, the co-existence of TDMA and W-CDMA spectrum sharing system (TDMA/W-CDMA overlaid system) with cellular architecture is discussed. In this system, both systems share the same frequency band to improve the spectrum efficiency. The overall rate and spectrum efficiency of the system are calculated for the forward link (down-link) in the presence of the AWGN channel. Taking into account the path loss and shadow fading loss in this system with cellular architecture, W-CDMA applying interference cancellation (IC) shows a substantial difference in spectrum efficiency, the overlaid system can provide a greater overall rate and higher spectrum efficiency than a single multiple access-based system such as the TDMA system or W-CDMA system.