The paper presents an adaptive receiver structure for reception of M-ary signals over a rapidly time varying mobile communication channel. The channel impulse response is expanded into a set of basis sequences and a time invariant (TI) expansion parameters. The proposed receiver continuously estimates the time invariant expansion parameters directly within the metric calculation of the log-likelihood function in a recursive manner. The performance of the receiver is evaluated in terms of the misdetection probability and is compared to other receivers. The effects of timing and phase offsets on the performance of receiver are examined by simulation. Finally, the proposed receiver can accommodate the rapidly time varying channel with adequate performance.