System and method for time slotted code division multiple access communication in a wireless communication environment

• US 20020122403A1
• Filed: 12/11/2001
• Published: 09/05/2002
• Est. Priority Date: 03/01/2001
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Earnshaw, Mark, Hashem, Bassam M., Fituri, Eman A.
• Granted Patent: US 7,061,898 B2
• Time in Patent Office: Days
• US Class Current: 370/342
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 8/22 Processing or transfer of terminal data, e.g. status or physical capabilities

Abstract

A method and apparatus for assigning a time slotted code division multiple access carrier for wireless reverse link communication between a device and a base station. One or more performance characteristics corresponding to the device are determined. A code division multiple access spreading code is assigned based on the determined performance characteristics. A time slot for communication with the base station is assigned based on the assigned spreading code. According to one aspect, the assigned spreading code corresponds to one of an SCDMA code and an ACDMA code such that a time slot corresponding to an SCDMA code provides a time slot in which all devices are preferably in time-aligned orthogonal communication with the base station. An increase in channel gain and an increase in channel capacity result as compared with a system where time slots support mixed ACDMA and SCDMA codes.

Claims

1. A method of assigning a time slot for wireless communication between a device and a base station, comprising:

determining one or more performance characteristics corresponding to the device;

assigning a spreading code based on the determined one or more performance characteristics; and

assigning a time slot for communication with the base station based on the assigned spreading code.

2. The method according to claim 1, wherein the assigned spreading code corresponds to one of a synchronous code division multiple access code and an asynchronous code division multiple access code.

3. The method according to claim 1, wherein the at least one performance characteristic corresponds to soft handoff operation.

4. The method according to claim 1, further comprising:

assigning a scrambling code, the scrambling code identifying the base station and identifying a spreading code set corresponding to the spreading code; and

assigning a total code, the total code being comprised of the assigned spreading code and the assigned scrambling code.

5. The method according to claim 4, wherein the base station has a plurality of scrambling codes corresponding thereto, the assigned scrambling code being selected from the plurality of scrambling codes.

6. The method according to claim 5, wherein the base station has a plurality of spreading code sets corresponding thereto, the assigned spreading code being selected from one of the plurality of spreading code sets.

7. The method according to claim 6, wherein a first combination of a first spreading code set with a scrambling code yields total codes which are orthogonal to a second combination of a second spreading code set with the scrambling code.

8. The method according to claim 1, further comprising reassigning at least one of the spreading code and the time slot assigned to the device based on a change in a performance characteristic of the device.

9. An apparatus for assigning a time slot for wireless communication between a device and a base station, the apparatus comprising:

a central processing unit, the central processing unit operating to;

determine one or more performance characteristics corresponding to the device;

assign a spreading code based on the determined one or more performance characteristics; and

assign a time slot for communication with the base station based on the assigned spreading code.

10. The apparatus according to claim 9, further comprising a communication interface, the communication interface in operative communication with the central processing unit and facilitating communication with the base station, wherein the central processing unit provides the assigned time slot to the base station for transmission to the device.

11. The apparatus according to claim 9, wherein the assigned spreading code corresponds to one of a synchronous code division multiple access code and an asynchronous code division multiple access code.

12. The apparatus according to claim 9, wherein the at least one performance characteristic corresponds to soft handoff operation.

13. The apparatus according to claim 9, wherein the central processing unit further operating to:

assign a scrambling code, the scrambling code identifying the base station and identifying a spreading code set corresponding to the spreading code; and

assign a total code, the total code being comprised of the assigned spreading code and the assigned scrambling code.

14. The apparatus according to claim 13, wherein the base station has a plurality of scrambling codes corresponding thereto, the central processing unit further operating to assign the scrambling code from the plurality of scrambling codes.

15. The apparatus according to claim 14, wherein the base station has a plurality of spreading code sets corresponding thereto, the central processing unit further operating to assign the spreading code from one of the plurality of spreading code sets.

16. The apparatus according to claim 15, wherein a first combination of a first spreading code set with a scrambling code yields total codes which are orthogonal to a second combination of a second spreading code set with the scrambling code.

17. The apparatus according to claim 9, further comprising reassigning at least one of the spreading code and the time slot assigned to the device based on a change in a performance characteristic of the device.

20. The method according to claim 19, wherein the code division multiple access spreading code is a synchronous code division multiple access spreading code.

18. A communication signal embodied in a wireless communication medium between a device and a base station, the wireless signal comprising a plurality of time slots, each of the plurality of time slots supporting communication from the device to the base station using one of synchronous code division multiple access codes and asynchronous code division multiple access codes.

19. A method of selecting spreading code sets associated with code division multiple access wireless communication between a device and a base station, the method comprising:

selecting a scrambling code being from a plurality of scrambling codes corresponding to the base station; and

selecting a code division multiple access spreading code set from a plurality of code division multiple access spreading code sets corresponding to the base station,

wherein a first combination of a first spreading code set with a scrambling code yields total codes which are orthogonal to a second combination of a second spreading code set with the scrambling code.