Efficient frame tracking in mobile receivers

DETAILED DESCRIPTION A method for frame tracking of a wireless communication channel is provided which allows signal processing at over-sampled transmission rates in a multipath environment.
The frame tracking method operates in conjunction with another algorithm to provide the final channel estimates.
These channel estimates are useful for a RAKE, an equalizer, or a multi-user detection (MUD) receiver for channel equalization.
Frame tracking of a mobile receiver is maintained to counteract motion of the receiver and local oscillator drift.
The frame tracking operates on the first significant signal path and updates its position at a relatively slow speed.
In response to this, channel estimation of the received multipath signal is enhanced by operating with a fixed short window size, which in turn allows frequent updates of channel estimates.
The frame tracking allows all moving paths to remain inside the channel estimation window.
As a result, fast changing profiles of the multipath propagation channel are estimated with improved accuracy.
Tracking each path is avoided by separating the frame tracking and channel estimation algorithms.
A method for frame synchronization of a receiver in a wireless communication system wherein data is transmitted in frame units in a multipath environment begins by extracting data samples for a predetermined window size.
A training sequence corresponding to a given cell parameter is generated.
The training sequence may be a pilot, as in FDD CDMA, or a midamble, as in TDD W-CDMA.
The data is correlated with the training sequence over different lags to locate the position of the first significant path, which defines the beginning of the frame.
The correlated data is accumulated N times for each lag position to produce at least one accumulation vector.
A most significant path value and position is determined that is the largest value among the accumulation vectors.
A frame synchronization correction value is calculated based on the difference between the first significant path position and a constant called frame offset