Pilot power allocation for CDMA systems with antenna arrays

This paper discusses the uplink of a third generation code division multiple access wireless system using antenna arrays at the base station. Each user sends a pilot signal with their modulated data, whose power can be varied as required by the base station. The uplink is then detected coherently using the pilot signal to estimate the channel coefficients for each mobile. Theoretical results on signal-to-noise ratio (SNR) degradation due to imperfect channel estimation are used to determine the optimum power allocation for the pilot signal in a Rayleigh fading environment. The results call be used for any SNR, for any channel Doppler frequency and for any receiver array size.