Use of orthogonal or near orthogonal codes in reverse link

• US 7,529,264 B2
• Filed: 06/14/2005
• Issued: 05/05/2009
• Est. Priority Date: 07/17/2001
• Status: Expired due to Fees

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr., Alapuranen, Pertti O.
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Chery; Dady
• Application Number:
  US11/152,858
• Publication Number:
  US 20050232140A1
• Time in Patent Office: 1,421 Days
• Field of Search: 370/441, 370/204, 370/208, 370/209, 370/335, 370/342, 370/203, 375/141, 375/145, 375/149
• US Class Current: 370/441
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04J 3/0635 Clock or time synchronisation in a network timer in protocols H04L69/28
• CPC Class Codes: H04L 7/043 Pseudo-noise [PN] codes variable during transmission synchronisation of spread spectrum receivers H04B1/69
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames

Abstract

A technique for allowing a first and second group of users to share access to a communication channel such as a wireless radio channel is disclosed. The first group of users can be a group of legacy users such as those that use digital CDMA cellular telephone equipment based on the IS-95 standard. The second group of users can be a group of web surfers that code their transmissions using one of multiple formats. The first group of users can share one modulation structure such as, on a reverse link, using unique phase offsets of a common pseudorandom noise (PN) code. The second group of users can share another modulation structure, but in a manner that is consistent and compatible with the users of the first group. Specifically, the users of the second group may all use the same PN code and code phase offset. Each channel used by the second group of users can be uniquely identified by a corresponding unique orthogonal code.

Claims

1. A method for code division multiple access communication

assigning to a first group of terminals a first pseudorandom noise code, each user of the first group of terminals being uniquely identifiable by a unique code phase offset, the first pseudorandom noise code being assigned to the first group of terminals by a first modulator;

assigning to a second group of terminals the first pseudorandom noise code, with each user of the second group of terminals also being assigned a common phase offset of the first pseudorandom noise code, the first pseudorandom noise code and common phase offset being assigned to the second group of terminals by a second modulator; and

assigning to each terminal of the second group of terminals a unique spreading code, the unique spreading code having a chipping rate less than a chipping rate of the first pseudorandom noise code, the spreading code being one of an orthogonal spreading code or a near-orthogonal spreading code, the spreading code being assigned by a third modulator.

2. The method according to claim 1, wherein the spreading code is a Walsh code.

3. The method according to claim 1, wherein the spreading code uniquely defines a separate logical channel.

4. The method according to claim 1 further comprising:

assigning to each terminal of the second group of terminals a feedback channel that enables each terminal to receive information, thereby enabling the terminal to advance or retard its timing for future communications.

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

receiving at the terminal, through the feedback channel, at least one of channel noise information or synchronization information.

6. The method according to claim 1, wherein the spreading code chipping rate of a terminal is proportional to a modulation symbol rate of the terminal.

7. The method according to claim 6, further comprising:

using adaptive modulation at the terminal, wherein the spreading code chipping rate matches the adaptive modulation symbol rate.

8. The method according to claim 7, wherein the terminal modulation rate is determined based on a C/I measurement received at the terminal in a feedback message.

9. The method according to claim 7, wherein the terminal forward error correction rate is determined based on a C/I measurement received at the terminal in a feedback message.

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

assigning one or more additional pseudorandom noise spreading codes to a terminal.

11. The method according to claim 10, wherein the spreading code has a chipping rate that is less than a chipping rate of one or more of the additional pseudorandom noise spreading codes.

12. The method according to claim 1, wherein the method is applied to at least one of a forward link or reverse link of a CDMA network.

13. An apparatus configured to support code division multiple access communications comprising:

a first modulator configured to assign to a first group of terminals a first pseudorandom noise code, each user, of the first group of terminals being uniquely identifiable by a unique code phase offset;

a second modulator configured to assign to a second group of terminals the first pseudorandom noise code, with each terminal of the second group of terminals using a common phase offset of the first pseudorandom noise code; and

a third modulator configured to assign to each terminal of the second group of terminals a unique spreading code, the unique spreading code having a chipping rate less than a chipping rate of the first pseudorandom noise code, the spreading code being one of an orthogonal spreading code or a near-orthogonal spreading code.