Method and apparatus for enabling subscriber stations to process a synchronization channel in a spread spectrum communications system

• US 7,505,437 B2
• Filed: 02/26/2002
• Issued: 03/17/2009
• Est. Priority Date: 02/26/2002
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tiedemann, Edward G. Jr., Wang, Jun, Sinnarajah, Ragulan
• Primary Examiner(s): Chan; Wing F
• Assistant Examiner(s): Tsegaye; Saba
• Application Number:
  US10/085,608
• Publication Number:
  US 20030161283A1
• Time in Patent Office: 2,576 Days
• Field of Search: 370/310, 370/320, 370/326, 370/331, 370/335, 370/341, 370/342, 370/465, 370/350, 455/442, 455/524, 455/525, 455/552
• US Class Current: 370/335
• CPC Class Codes: H04B 7/2634 for channel frequency control
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

During initiation procedure between subscriber stations and access network adhering to CDMA standards, (e.g., IS-95 and IS-2000) the subscriber station receives a Sync Channel Message. Due to a design/manufacturing error, certain subscriber stations adhering to the IS-95 fail to ignore a portion of the Sync Channel Message, intended for a proper operation of subscriber stations adhering to the IS-2000. This causes a failure of the IS-95 subscriber stations'"'"' operation. The disclosed invention describes embodiments allowing the faulty subscriber stations to operate on an access networks build in accordance with both IS-95 and IS-2000 standards.

Claims

1. A method for frequency and channel assignment for sectors in a spread spectrum communications system, the method comprising:

modulating a message on a first synchronization channel transmitted on at least one first frequency from at least one sector;

modifying the message to generate a single modified message and beginning with a Protocol Revision (P REV) field, including a CDMA Frequency Assignment (CDMA FREQ) field, and ending with an Extended CDMA Frequency Assignment (EXT CDMA FREQ) field;

wherein the CDMA Frequency Assignment (CDMA FREQ) field is immediately before and adjacent to the Extended CDMA Frequency Assignment (EXT CDMA FEQ) field; and

modulating the modified message on a second synchronization channel transmitted on at least one second frequency from the at least one sector.

2. The method as claimed in claim 1, wherein said modulating a message on a first synchronization channel transmitted on at least one first frequency from the at least one sector comprises:

modulating a Sync Channel Message on a first synchronization channel transmitted on at least one first frequency from the at least one sector.

3. The method as claimed in claim 1, wherein said modulating the modified message on a second synchronization channel transmitted on at least one second frequency from the at least one sector comprises:

modulating the modified Sync Channel Message on a second synchronization channel transmitted on at least one second frequency from the at least one sector.

4. The method as claimed in claim 1, wherein said modulating the modified message on a second synchronization channel transmitted on at least one second frequency from the at least one sector comprises:

deleting at least one field from the message.

5. A method for frequency and channel assignment for sectors in a spread spectrum communications system, the method comprising:

modulating a message on a first synchronization channel transmitted on at least one first frequency from at least one sector;

modulating the message to generate a single modified message, the single modified message consisting of;

a P REV (Protcol Revision) field,

a MIN P REV field,

a SID field,

a NID field,

a PILOT PN field,

a LC state field,

a SYS TIME field,

a LP SEC field,

a LTM OFF field,

a DAYLT field,

a PRAT field,

a CDMA FREQ (CDMA Frequency Assignment field, and

a EXT CDMA FREQ (Extended CDMA Frequency Assignment) field; and

modulating the single modified message on a second synchronization channel transmitted on at least one second frequency from the at least one sector.

6. The method as claimed in claim 5, wherein:

the CDMA FREQ field consists of eleven bits; and

the EXT CDMA FREQ field consists of eleven bits.

7. The method as claimed in claim 5, wherein said modulating the modified message on a second synchronization channel transmitted on at least one second frequency from the at least one sector comprises:

deleting at least one field, occurring after the EXT CDMA FREQ field, from the message.

8. A method for frequency and channel assignment for sectors in a spread spectrum communications system, the method comprising:

modulating a message on a first synchronization channel transmitted on at least one first frequency from at least one sector;

modulating the message to generate a single modified message, the single modified message consisting of;

a P REV (Protcol Revision) field,

a MIN P REV field,

a SID field,

a NID field,

a PILOT PN field,

a LC state field,

a SYS TIME field,

a LP SEC field,

a LTM OFF field,

a DAYLT field,

a PRAT field,

a CDMA FREQ (CDMA Frequency Assignment field, and a EXT CDMA FREQ (Extended CDMA Frequency Assignment) field, wherein the CDMA FREQ is adjacent to the EXT CDMA FREQ field; and

modulating the single modified message on a second synchronization channel transmitted on at least one second frequency from the at least one sector.

9. The method as claimed in claim 8, wherein:

the CDMA FREQ field consists of eleven bits; and

the EXT CDMA FREQ field consists of eleven bits.

10. The method as claimed in claim 8, wherein said modulating the modified message on a second synchronization channel transmitted on at least one second frequency from the at least one sector comprises:

deleting at least one field, occurring after the EXT CDMA FREQ field, from the message.