Maximum total ergodic spectral efficiency of randomly-spread coded-CDMA with linear multiuser receivers over multipath fading channels

In this paper, we analyze the total ergodic spectral efficiency and sum-rates error-exponents of randomly-spread CDMA systems with diversity-combining linear multiuser receivers over time-varying frequency-selective multipath Rayleigh/Ricean fading channels. The basis of our analysis mainly being the joint/average eigenvalue density of the random cross-correlation matrices, our focus is on equal-rate/equal-energy identical users with statistically i.i.d. channels. The upper-bound ergodic spectral efficiency and the corresponding sum-rates error-exponent expressions are derived in closed-form in terms of the key system parameters for linear multiuser receivers with single-user ML decoding. The analysis sheds light onto asymptotic behaviour of channel-coded wideband CDMA systems over multipath fading channels.