Smart Antenna System for Interference Reduction in GSM Handset

With the introduction of internet data services in mobile terminals (ex. WAP) new high data rates are required. Currently new GSM terminals are provided with HSCSD (High-Speed Circuit-Switched Data) and GPRS (General Packet Radio Service) to address the need for increased data capabilities. HSCSD introduces multislot operation and GPRS packet services, whereby the user can remain connected to the network, but only take up radio capacity when needed. HSCSD and GPRS are based on the original GMSK (Gaussian Minimum-Shift Keying) modulation, so they only provide a moderate increase in bit rate per timeslot. To increase the data rates further the next generation GSM terminals will include EGPRS (Enhanced GPRS) as well, which uses the modulation scheme 8-PSK. With the introduction of EGPRS a data rate of up to 384 kbit/s is possible, but only at very high SNR and CIR levels. However by using an antenna system (i.e. more than one antenna port) in the handset it is possible to combine the signals from the antennas in such a way that both the SNR and CIR level is improved. The main objective of this work has been to analyse the potential improvements of the downlink signal-to-interference-plus-noise-ratio (SINR), which can be obtained by introducing a low complexity pre-detection antenna system in the mobile terminal [M.B. Knudsen, T. Baumgartner, G.F. Pedersen, May 2000 (a)], [M.B. Knudsen, J. Brøndum, G.F. Pedersen, November 2000 (e)]. Simulation results are described in CPK Annual Report (M. B. Knudsen, G. F. Pedersen, J. Brøndum)