System and method for maintaining timing of synchronization messages over a reverse link of a CDMA wireless communication system

• US 7,773,566 B2
• Filed: 07/21/2004
• Issued: 08/10/2010
• Est. Priority Date: 06/01/1998
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Tantivy Communications Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr.
• Primary Examiner(s): Mattis; Jason E
• Application Number:
  US10/895,591
• Publication Number:
  US 20050013284A1
• Time in Patent Office: 2,211 Days
• Field of Search: 370/329, 370/335, 370/350
• US Class Current: 370/335
• CPC Class Codes: H04B 1/7085 using a code tracking loop, e.g. a delay-locked loop
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04W 74/00 Wireless channel access

Abstract

A method for operating a subscriber unit that communicates with a code division multiple access (CDMA) wireless network is provided. At the subscriber unit, synchronization information is encoded with a CDMA code. The CDMA encoded synchronization information is transmitted from the subscriber unit in discrete repeating intervals. The discrete repeating intervals are separated by other discrete repeating intervals during which the subscriber unit does not transmit synchronization information.

Claims

1. A method for use in a subscriber unit in a code division multiple access (CDMA) wireless network, the method comprising:

receiving a message defining a timeslot assignment for a code phase reverse channel of the subscriber unit, wherein the timeslot assignment defines timeslots to be used only during an idle mode;

encoding synchronization information with a CDMA code;

monitoring a buffer to determine whether additional code phase channels are required to support the reverse channel;

on a condition that the additional code phase channels are not required, the subscriber unit remains in the idle mode; and

transmitting, during the idle mode, the CDMA encoded synchronization information on an assigned code phase channel, wherein the transmission of the CDMA encoded synchronization information is based on the received timeslot assignment.

2. The method of claim 1 further comprising:

monitoring the buffer;

supplying user information to the buffer;

requesting permission to use a first CDMA code for supporting transmission of a portion of the user information;

requesting permission to use a second CDMA code for supporting transmission of the user information not in the portion; and

transmitting the user information using the first CDMA code and the second CDMA code.

3. The method of claim 1 wherein the message defining the timeslot assignment defines a repeating timeslot interval.

4. The method of claim 1 wherein the CDMA encoded synchronization information comprises a heartbeat message.

5. The method of claim 1 wherein the transmitting of the CDMA encoded synchronization information occurs when the subscriber unit is in an idle mode and does not occur when the subscriber unit is transmitting user information.