Iterative CDMA Receiver with EM Channel Estimation and Turbo Decoding

This paper presents an efficient iterative code-division multiple-access direct-sequence system that uses a turbo code and requires few pilot symbols for carrier estimation and tracking. The signal strength and the noise-power spectral density are separately estimated by applying the expectation maximization (EM) algorithm. The higher throughput of the proposed system relative to a conventional 3 ^rd Generation Partnership Project system is verified through simulations using a Jakes fading environment. The complexity of the proposed EM iterative parameter-estimation scheme is low because the required number of complex multiplications is equal to only four times the fading block size