MULTI-USER DETECTION USING EQUALIZATION AND SUCCESSIVE INTERFERENCE CANCELLATION

• US 20090316759A1
• Filed: 08/25/2009
• Published: 12/24/2009
• Est. Priority Date: 03/03/2003
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Zeira, Ariela
• Granted Patent: US 8,249,191 B2
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04B 1/71072 Successive interference cancellation
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference

Abstract

A method and apparatus for multi-user detection using equalization and successive interference cancellation is provided. A signal is received in a shared spectrum. Samples of the received signal are produced as a received vector. The received vector is segmented into a plurality of vector segments. For each segment, symbols for a plurality of communications are successively determined by determining symbols for a communication and removing a contribution of that communication from the vector segment. The determined symbols are assembled into a data vector for each communication.

Claims

1. A method for use in wireless communication, the method comprising:

receiving a signal in a shared spectrum;

producing samples of the received signal as a received vector;

segmenting the received vector into a plurality of vector segments;

for each vector segment, successively determining symbols for a plurality of communications by determining symbols for a communication in the plurality of communications and removing a contribution of the communication from the vector segment; and

assembling the determined symbols into a data vector for each communication in the plurality of communications.

2. The method of claim 1, wherein the successively determining symbols for a plurality of communications includes ordering the communications by received power.

3. The method of claim 1, wherein the determining symbols for a communication includes equalizing the vector segment for the communication, despreading the equalized vector segment, and making a hard decision on the despread equalized vector segment.

4. The method of claim 3, wherein the equalizing the vector segment includes applying a fast Fourier transform to the vector segment.

5. The method of claim 3, wherein the despreading the equalized vector segment includes applying a code associated with the communication to produce a despread equalized vector segment including a plurality of soft symbols.

6. The method of claim 1, wherein the removing a contribution of the communication includes subtracting the determined symbols from the vector segment.

7. The method of claim 1, wherein the successively determining symbols for a plurality of communications includes determining symbols for a communication of interest.

8. A wireless transmit/receive unit (WTRU) comprising:

an antenna configured to receive a signal in a shared spectrum;

a sampling device configured to produce samples of the received signal as a received vector;

a segmentation device configured to segment the received vector into a plurality of vector segments;

a equalization and successive interference canceller configured to successively determine for each vector segment symbols for a plurality of communications by determining symbols for a communication in the plurality of communications and removing a contribution of the communication from the vector segment; and

a segment reassembly device configured to assemble the determined symbols into a data vector for each communication in the plurality of communications.

9. The WTRU of claim 8, wherein the equalization and successive interference canceller includes an equalizer configured to equalize the vector segment, a despreader configured to despread the equalized vector segment, and a hard decision device configured to make hard decisions on the despread equalized vector segment.

10. The WTRU of claim 9, wherein the equalizer is configured to equalize the vector segment using a fast Fourier transform.

11. The WTRU of claim 9, wherein the despreader is configured to produce a despread equalized vector segment including a plurality of soft symbols by apply a code associated with the communication to the equalized vector segment.

12. The WTRU of claim 8, wherein the equalization and successive interference canceller is configured to removing a contribution of the communication from the vector segment by subtracting the determine symbols from the vector segment.

13. The WTRU of claim 8, wherein the equalization and successive interference canceller is configured to determining symbols for a communication of interest.

14. A base station comprising:

an antenna configured to receive a signal in a shared spectrum;

a sampling device configured to produce samples of the received signal as a received vector;

a segmentation device configured to segment the received vector into a plurality of vector segments;

a equalization and successive interference canceller configured to successively determine for each vector segment symbols for a plurality of communications by determining symbols for a communication in the plurality of communications and removing a contribution of the communication from the vector segment; and

a segment reassembly device configured to assemble the determined symbols into a data vector for each communication in the plurality of communications.

15. The base station of claim 14, wherein the equalization and successive interference canceller includes an equalizer configured to equalize the vector segment, a despreader configured to despread the equalized vector segment, and a hard decision device configured to make hard decisions on the despread equalized vector segment.

16. The base station of claim 15, wherein the equalizer is configured to equalize the vector segment using a fast Fourier transform.

17. The base station of claim 15, wherein the despreader is configured to produce a despread equalized vector segment including a plurality of soft symbols by apply a code associated with the communication to the equalized vector segment.

18. The base station of claim 14, wherein the equalization and successive interference canceller is configured to removing a contribution of the communication from the vector segment by subtracting the determine symbols from the vector segment.

19. The base station of claim 14, wherein the equalization and successive interference canceller is configured to determining symbols for a communication of interest.