Experimental CDMA data overlay of GSM network

摘要

A broadband 64 Kbit/s DS-CDMA overlay which operates on the same carrier frequency as a downlink GSM signal is proposed. Error free operation of both systems has been demonstrated over a 70 dB power range. A novel CDMA receiver architecture allowed programmable digital notch filters to be implemented directly at RF. It is shown that the overall network capacity is increased by a factor of 3.3 compared to the case of a single GSM carrier only, as detailed in a previous theoretical analysis. This represents the first experimental demonstration of a CDMA overlay of a GSM network.