Abstract: The invention provides a receiver that is capable of deducing the timing of a received signal having a frame structure and corresponding methods. Each frame contains a synchronization word. The receiver correlates the known synchronization word against the received signal to determine the position of the synchronization word. The correlation results can be accumulated over several frames' worth of the signal in order to enhance the determination. The frame boundaries within the signal can be translated and the process of determining the synchronization word position can then be repeated. In this manner, several results for the synchronization word position can be obtained and the best selected. A thresholding process can be used to curtail the number of frames' worth of the received signal that needs to be processed and a mechanism is provided to prevent the thresholding process from biasing the determination of the synchronization word position.

Abstract: A method of classifying a ray is disclosed, the ray being received at a code division multiple access receiver. The method comprises: determining if a timing characteristic of the ray falls within a predetermined range of a timing characteristic of a ray classified to a given cell; in response to a positive determination, mixing a received signal with a scrambling code used by the given cell to provide a mixed signal; and examining the mixed signal to determine if the ray originates from the given cell.

Abstract: The circuit (10) performs a butterfly calculation for a Viterbi trellis by using two path metrics and a branch metric to generate two new path metrics. The new metrics are produced by adders (12) and (14) whose inputs are controlled by selectors (16-22). The outputs of the selectors (16-22) are controlled by selection control unit (24) which considers the difference between the given path metrics relative to the double of the branch metric, which represents a branch metric difference.

Abstract: A stream of recursive systematic convolutional codes Pn is generated by XORing each bit of an input bit stream In with a predetermined bit of the content of a cyclic shift element (22). The content of the shift element (22) is updated by adder (24) under the control of the input bit stream In.

Abstract: The processor (24) retrieves from a memory (22) values of a signal recovered from received wireless signal and demultiplexes and de-interleaves them simultaneously. The system can be operated in reverse to produce a multiplexed, interleaved data stream for wireless transmission.