PN generators for spread spectrum communications systems

• US 20040052302A1
• Filed: 09/10/2003
• Published: 03/18/2004
• Est. Priority Date: 01/31/2000
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Black, Peter J., Padovani, Roberto, Weaver, Lindsay A. Jr.
• Granted Patent: US 8,611,310 B2
• Time in Patent Office: Days
• US Class Current: 375/146
• CPC Class Codes: H03K 3/84 Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/10 Code generation

Abstract

Techniques to improve the acquisition process in a spread spectrum environment. The signals from different CDMA systems are spread with different sets of PN sequences, with the PN sequences in each set being uncorrelated to the PN sequences in the other sets. The mobile station can attempt to acquire the pilot signal by processing the received signal with a first set of PN sequences corresponding to a first hypothesis of the particular signal being acquired. If acquisition of the pilot signal fails, a second set of PN sequences corresponding to a second hypothesis is selected and used to process the received signal. The PN sequences in the second set are uncorrelated to the PN sequences in the first set.

Claims

1. An apparatus, comprising:

a first device to transmit at a first frequency;

a first PN generator to generate a first PN sequence at a first offset;

a first spreader to receive and spread a first pilot data with the first PN sequence;

a second device to transmit at a second frequency;

a second PN generator to generate a second PN sequence at a second offset; and

a second spreader to receive and spread a second pilot data with the second PN sequence, wherein the first device is positioned to transmit over at least a portion of the same geographic area as the second device.

2. The apparatus of claim 1, wherein the first frequency uses is a different CDMA format than the second frequency.

3. The apparatus of claim 2, wherein the first frequency is generated from a first CDMA format chosen from the group consisting of PCS, IS-95, IS-98, WCDMA, UTRA, IS-2000 and CDMA 2000, the second frequency is generated from a second CDMA format chosen from the group consisting of PCS, IS-95, IS-98, WCDMA, UTRA, IS-2000 and CDMA 2000 and wherein, the first CDMA format is different from the second CDMA format.

4. The apparatus of claim 1, wherein the first PN sequence is the reverse of the second PN sequence.

5. The apparatus of claim 1, wherein the first PN generator is capable of generating a sequence based on characteristic polynomials comprising:

P_I,1=x¹⁵+x¹³+x⁹+x⁸+x⁷+x⁵+1,andP_Q,1=x¹⁵+x¹²+x¹¹+x¹⁰+x⁶+x⁵+x⁴+x³+1.

6. The apparatus of claim 1, wherein the second PN generator is capable of generating a sequence based on characteristic polynomials comprising:

P_I,2=x¹⁵+x¹⁰+x⁸+x⁷+x⁶+x²+1,andP_Q,2=x¹⁵+x¹²+x¹¹+x¹⁰+x⁹+x⁵+x⁴+x³+1.

7. The apparatus of claim 1, further comprising a third device to transmit at a third frequency comprising a third PN generator to generate a third PN sequence at a third offset and a third spreader to receive and spread a third pilot data with the third PN sequence.

8. An apparatus, comprising:

a plurality of devices to transmit a plurality of signals each using a different CDMA format;

means for generating a plurality of pilot signals from uncorrelated PN sequences for the plurality of signals.

9. The apparatus of claim 8 wherein means for generating the plurality of pilot signals is based on the polynomials comprising:

P_I,1=x¹⁵+x¹³+x⁹+x⁸+x⁷+x⁵+1,andP_Q,1=x¹⁵+x¹²+x¹¹+x¹⁰+x⁶+x⁵+x⁴+x³+1.

10. The apparatus of claim 8 wherein means for generating the plurality of pilot signals is based on the polynomials comprising:

P_I,2=x¹⁵+x¹⁰+x⁸+x⁷+x⁶+x²+1,andP_Q,2=x¹⁵+x¹²+x¹¹+x¹⁰+x⁹+x⁵+x⁴+x³+1.

11. The apparatus of claim 8, wherein means for generating the plurality of pilot signals includes at least one pilot signal that is gated in time.