METHOD AND APPARATUS FOR ENABLING SUBSCRIBER STATIONS TO PROCESS A SYNCHRONIZATION CHANNEL IN A SPREAD SPECTRUM COMMUNICATIONS SYSTEM

• US 20090161634A1
• Filed: 01/30/2009
• Published: 06/25/2009
• Est. Priority Date: 02/26/2002
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sinnarajah, Ragulan, Wang, Jun, Tiedemann, Edward G. JR.
• Application Number:
  US12/363,620
• Publication Number:
  US 20090161634A1
• Time in Patent Office: Days
• 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. An apparatus for frequency and channel assignment for sectors in a spread spectrum communications system, the apparatus comprising:

a processor that modifies a synchronization message to generate a single modified message, the modified message comprises a Protocol Revision (P REV) field and a CDMA Frequency Assignment (CDMA FREQ) field, the synchronization message comprises the modified message and an Extended CDMA Frequency Assignment (EXT CDMA FREQ) field;

a first modulator that modulates the modified message on a first synchronization channel transmitted on at least one first frequency from at least one sector; and

a second modulator that modulates the synchronization message on a second synchronization channel transmitted on at least one second frequency from the at least one sector.

2. The apparatus of claim 1, wherein modulating the modified message on the 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.

3. An apparatus for frequency and channel assignment for sectors in a spread spectrum communications system, the apparatus comprising:

a first modulator that modulates a message on a first synchronization channel transmitted on at least one first frequency from at least one sector;

the message comprising;

a P REV (Protocol 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

a processor that modifies the message thereby forming a modified message; and

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

4. The apparatus of claim 3, wherein:

the CDMA FREQ field consists of eleven bits; and

the EXT CDMA FREQ field consists of eleven bits.

5. The apparatus of claim 3, wherein modulating the modified message on the 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 CDMA FREQ field, from the message.

6. An apparatus for frequency and channel assignment for sectors in a spread spectrum communications system, the apparatus comprising:

means for modifying a synchronization message to generate a single modified message, the modified message comprises a Protocol Revision (P REV) field and a CDMA Frequency Assignment (CDMA FREQ) field, the synchronization message comprises the modified message and an Extended CDMA Frequency Assignment (EXT CDMA FREQ) field;

means for modulating the modified message on a first synchronization channel transmitted on at least one first frequency from at least one sector; and

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

7. An apparatus for frequency and channel assignment for sectors in a spread spectrum communications system, the apparatus comprising:

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

the message comprising;

a P REV (Protocol 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

means for modifying the message thereby forming a modified message; and

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

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

determining a first portion of a synchronization message, the first portion of the synchronization message is usable by devices compatible with a first communication standard and the entire synchronization message is usable by devices compatible with a second communication standard;

modulating the first portion of the synchronization message on a first synchronization channel transmitted on at least one first frequency from at least one sector; and

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

9. The method of claim 8, further comprising:

receiving an indication from at least one device compatible with the second communication standard; and

transmitting an redirection message to each of the at least one device compatible with the second communication standard.

10. The method of claim 9, wherein the redirection message comprises information directing the at least one device to tune to a particular frequency.

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

means for determining a first portion of a synchronization message, the first portion of the synchronization message is usable by devices compatible with a first communication standard and the entire synchronization message is usable by devices compatible with a second communication standard;

means for modulating the first portion of the synchronization message on a first synchronization channel transmitted on at least one first frequency from at least one sector; and

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

12. A computer program product comprising:

a computer-readable medium comprising;

code for causing a computer to determine a first portion of a synchronization message, the first portion of the synchronization message is usable by devices compatible with a first communication standard and the entire synchronization message is usable by devices compatible with a second communication standard;

code for causing a computer to modulate the first portion of the synchronization message on a first synchronization channel transmitted on at least one first frequency from at least one sector; and

code for causing a computer to modulate the entire synchronization message on a second synchronization channel transmitted on at least one second frequency from the at least one sector.