| Computer simulations of mobile communication systems often use ideal or simple channel propagation models. This assumption is sufficient for relative comparison of algorithms or for testing overall functionality, but insufficient when the actual performance in a physical environment is required. In order to perform physical experiments, a low-cost modular wideband CDMA smart antenna measurement system operating in the 1.9 GHz band has been designed and constructed.; Previous approaches include the studying of DOA (direction-of-arrival) estimation, spatial signature or angle spread at the 1.8–2.0 GHz band using narrowband measurement systems. Other wideband testbeds employ a single transmitter to analyze antenna array receiver performance, beamforming and multipath delay profile.; Our complete system can operate within the frequency range of 1–2 GHz, with multiple portable transmitters and a multiple element antenna array receiver basestation. The transmitters are programmable, allowing varying PN chip-rates and PN code sequences, and the receiver can simultaneously acquire 16k samples per antenna element at 5 samples per PN chip.; Our experimental data allowed us to characterize an outdoor wideband CDMA channel including multipath peak amplitudes and delays, channel and spatial signature variation. In addition, using signal subspace processing, we compared mobile-to-basestation beamforming performance to that of a single antenna. Results from a 4-user scenario show that a user can get an average SINR gain of 0.176 to 3.335 dB from maximum SINR beamforming. |
