In one embodiment, the present invention includes a method for determining a level of a buffer that stores data samples. The level may be determined at a predetermined position of a data frame sequence. Based on the level of the buffer at this position, a vocoder and modem of a mobile station may be synchronized. One or both of the vocoder and modem may be adjusted to attain the synchronization. Thus a rate mismatch between the vocoder and modem may be resolved.