— In this paper, an innovative frequency domain joint estimation algorithm of synchronization parameter and channel impulse response (CIR) in Direct Sequence Code Division Multiple Access (DS-CDMA) system is proposed. This algorithm is based on the expectation-maximization (EM) method. Because this algorithm can provide accurate estimation of channel conditions and synchronization parameter for DS-CDMA receivers, even with a simple equalization module, for example, a one-tap multiplier based frequency domain equalizer (FDE), a receiver architecture following this approach can still provide better performance than the costly multi-tap multiplier based equalizer, such as the time domain equalizer (TDE). Performance is well maintained under fast fading channel for mobile stations at high velocity. Moreover, a generic receiver architecture purely based on frequency domain equalization for a composite radio environment, that is CDMA and Orthogonal Frequency-Division Multiplexing (OFDM) sy...