Granted Patent B2

US 6,954,487 · App. 09/729,900 · Granted Oct 11, 2005

Abstract

Claims (14)

1. A method of recovering transmitted symbols in a receiver of a spread spectrum system, comprising the steps of: receiving a signal including multi-path components associated with transmitted symbols; and de-spreading successive separate portions of the received signal to provide a symbol estimate based on each multi-path component, wherein: each said successive separate portion contains at least one complete multi-path component of the transmitted symbols and at least one partial multi-path component of the transmitted symbols; the de-spreading step comprises determining, for each partial multi-path component, one partial symbol estimate associated with a one of the transmitted symbols; and the method further comprises summing, over two or more said successive separate portions, the partial symbol estimates corresponding to a same one of the transmitted symbols.

2. The method of claim 1 further comprising the step, after de-spreading each successive separate portion, of storing any partial estimates.

3. The method of claim 2 further comprising the step, on de-spreading each successive separate portion, of retrieving any stored partial estimates assoicated with a same transmitted symbol in the current portion.

4. The method of claim 3 wherein the any retrieved partial estimates are used in the summing step.

5. The method of claim 1 further including the step of sampling the received signal at successive time intervals thereby generating the successive separate portions of the received signal.

6. The method of claim 5 further comprising the step of estimating a timing error of the received signal, wherein the successive separate portions of the received signal are time adjusted to compensate for the timing error prior to de-spreading.

7. The method of claim 6 wherein the successive separate portions of the received signal are stored in a sample memory.

8. The method of claim 7 wherein the successive separate portions of the received signal have a length of more than one symbol period.

9. The method of claim 8 wherein the successive separate portions of the received signal have a length of two symbol periods.

10. In a receiver of a spread spectrum communication system, circuitry for recovering transmitted symbols, comprising: sample circuitry, connected to input a received signal including multi-path components of at least one symbol, for sampling successive separate portions of the received signal, each said successive separate portion containing at least one complete multi-path component of the transmitted symbols and at least one partial multi-path component of the transmitted symbols; de-spreading circuitry, connected to receive the successive separate portions of the received signal and for outputting a symbol estimate by determining, for each partial multi-path component, one partial symbol estimate associated with a one of the transmitted symbols and summing circuitry for summing, over two or more said successive separate portions, the partial symbol estimates corresponding to a same one of the transmitted symbols, thereby to produce a full estimate.

11. The circuitry of claim 10 further including a memory for storing the partial estimates, wherein at the end of de-spreading each successive separate portion of the received signal, any partial estimates are stored in said memory.

12. The circuitry of claim 11 further including a symbol memory, wherein each full estimate is stored in the symbol memory.

13. The circuitry of any claim 12 wherein the sample circuitry includes a sample memory, wherein the successive separate portions of the received signal are stored in the sample memory.

14. The circuitry of claim 13 , further including timing error detection and estimation circuitry for determining an error in the timing position of the received signal, wherein the timing position of the received signal is adjusted responsive to said error prior to de-spreading.

Assignments (9)