MULTI-USER DETECTOR AND METHOD FOR USE IN A COMMUNICATION SYSTEM

• US 20090054060A1
• Filed: 05/10/2005
• Published: 02/26/2009
• Est. Priority Date: 05/20/2004
• Status: Active Grant

• Current Assignee: NVIDIA Corporation
• Original Assignee: IPWireless Inc. (NVIDIA Corporation)
• Inventors: Jones, Alan Edward
• Granted Patent: US 8,228,877 B2
• Time in Patent Office: Days
• US Class Current: 455/434
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects

Abstract

A multi-user detector (200) and method (300) for use in a cellular CDMA system (100) based on: estimating (210) spare code resource available in a first cell of the system; selecting (220) at least a second cell neighbouring the first cell; selecting (230) from codes associated with the second cell at least one additional code; and performing (240) multi-user detection processing in the first cell with the at least one additional code. On the downlink, codes from other users in the same cell may be treated with the same level of priority as those of users from neighbour cells, codes allocated to the UE having the highest priority; on the uplink, codes of all users in the same cell may have the same priority which is higher than that of neighbour cell users. This provides the advantage(s) that multi-user detector capacity arising from operating under high interference conditions is employed to accommodate users from neighbour cells, with the result that both intracell and intercell interference may be mitigated.

Claims

1. A wireless communication unit comprising a multi-user detector for use in a Code Division Multiple Access (CDMA) cellular communication system, the multi-user detector comprising:

spare resource estimation logic for estimating spare code resource available in a first cell of the CDMA cellular communication system;

neighbour cell selection logic for selecting at least a second cell neighbouring the first cell;

code selection logic for selecting from codes associated with the second cell at least one additional code; and

multi-user detector processing logic for performing multi-user detection processing in the first cell with the at least one additional code.

2. The wireless communication unit claim 1 wherein the multi-user detector processing logic is capable of being arranged to treat codes associated with the first cell with a same priority as the at least one additional code associated with the second cell and to treat at least a first code associated with a first mobile station with a higher priority.

3. The wireless communication unit claim 1 wherein the multi-user detector processing logic is capable of being arranged to treat codes associated with the first cell with higher priority than the at least one additional code associated with the second cell.

4. The wireless communication unit claim 1, wherein the spare resource estimation logic comprises allocated code resource estimation logic for estimating allocated code resource in the first cell from predetermined parts of signals received in the first cell.

5. The wireless communication unit of claim 4 wherein the predetermined parts comprise midamble sequences.

6. The wireless communication unit of claim 1 wherein the neighbour cell selection logic comprises autonomous decision logic for autonomously deciding the at least a second cell neighbouring the first cell.

7. The wireless communication unit claim 6 wherein the autonomous decision logic is arranged to autonomously decide on the basis of at least one of A-B:

A physical layer measurements,

B information known a priori.

8. The wireless communication unit of claim 7 wherein the physical layer measurements comprise neighbour cell power measurements.

9. The wireless communication unit claim 1 wherein the neighbour cell selection logic comprises network-instructed selection logic for receiving from the network instruction for selecting the at least a second cell neighbouring the first cell.

10. The wireless communication unit of claim 1 wherein the code selection logic comprises logic for forming a first set of codes and a second set of codes and is capable of being arranged to select codes for the multi-user detector processing logic with a higher priority for codes of the first set of codes than for codes of the second set of codes.

11. The wireless communication unit of claim 10 wherein the code selection logic is capable of being arranged to select all codes from the first set for the multi-user detector processing logic.

12. The wireless communication unit of claim 10 wherein the code selection logic is capable of being arranged to determine a remaining code capacity for the multi-user detector processing logic following selection of codes from the first set of codes.

13. The wireless communication unit of claim 12 wherein the code selection logic capable of being is arranged to select a number of codes of the second set of codes corresponding to a remaining code capacity for the multi-user detector processing logic.

14. The wireless communication unit of claim 10 wherein the code selection logic is capable of being arranged to determine an ordered list of codes in the second set of codes based on respective power measurements, and for selecting codes from the list in response to the respective power measurements.

15. The wireless communication unit of claim 14 wherein a respective power measurement comprises a measurement of power of a midamble signal.

16. The wireless communication unit of claim 14 wherein a respective power measurement comprises a measurement of power of a pilot signal.

17. The wireless communication unit of claim 10 wherein all codes of the first set of codes have a first priority and all codes of the second set of codes have a second priority.

18. The wireless communication unit of claim 1 adapted to operate in Universal Mobile Telecommunication System Terrestrial Radio Access (UTRA) system.

19. The wireless communication unit of claim 1 adapted to operate in 3^rd Generation Partnership Project (3GPP) system.

20. The wireless communication unit of claim 1 adapted to operate in Time Division Duplex (TDD) system.

21. The wireless communication unit of claim 1 wherein the wireless communication unit is User equipment comprising the multi-user detector.

22. The wireless communication unit of claim 1 wherein the wireless communication unit is abase station comprising the multi-user detector.

23. An integrated circuit comprising a multi-user detector wherein the multi-user detector comprises:

spare resource estimation logic for estimating spare code resource available in a first cell of the system;

neighbour cell selection logic for selecting at least a second cell neighbouring the first cell;

code selection logic for selecting from codes associated with the second cell at least one additional code; and

multi-user detector processing logic for performing multi-user detection processing in the first cell with the at least one additional code.

24. A method of multi-user detection in a Code Division Multiple Access (CDMA) cellular communication system, the method comprising:

estimating spare code resource available in a first cell of the system;

selecting at least a second cell neighbouring the first cell;

selecting from codes associated with the second cell at least one additional code; and

performing multi-user detection processing in the first cell with the at least one additional code.

25. The method of claim 24 wherein performing multi-user detection processing comprises:

treating codes associated with the first cell with a same priority as the at least one additional code associated with the second cell, and

treating at least a first code associated with a first mobile station with a higher priority.

26. The method of claim 25 wherein performing multi-user detection comprises:

treating codes associated with the first cell with higher priority than the at least one additional code associated with the second cell.

27. The method of claim 24 wherein selecting at least a second cell neighbouring the first cell comprises:

receiving from a network instruction for selecting the at least a second cell neighbouring the first cell.

28. The method of claim 24 wherein selecting from codes associated with the second cell at least one additional code comprises:

forming a first set of codes having higher priority and a second set of codes having lower priority,

forming an ordered list of codes in the second set of codes based on respective power measurements, and

selecting from the ordered list at least one code having a power measurement above a predetermined threshold.