MULTIPLEXED CDMA AND GPS SEARCHING

• US 20100222076A1
• Filed: 05/07/2010
• Published: 09/02/2010
• Est. Priority Date: 01/07/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Zou, Qiuzhen, Poon, Wang Paul
• Granted Patent: US 8,582,623 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: H04B 1/70754 Setting of search window, i.e. range of code offsets to be searched H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/70758 Multimode search, i.e. using multiple search strategies
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 2201/70711 with modular structure

Abstract

Searcher hardware is multiplexed to perform simultaneous searches in either an IS-95 CDMA mode or a GPS mode. In the IS-95 mode, the search hardware is time-multiplexed into a number of searcher time slices, each of which can generate a PN sequence to despread a data sequence. In the GPS mode, the search hardware is configured as a number of distinct GPS channels, each of which can generate a Gold code sequence for tracking a GPS signal from a particular GPS satellite. This configuration allows the searcher to perform multiple GPS signal searches simultaneously. Signal searching in both IS-95 and GPS modes is performed at significantly higher speeds compared to conventional searcher hardware. Moreover, the search hardware can be dynamically configured to operate in either the IS-95 or the GPS mode, eliminating the need for dedicated circuitry for each mode of operation.

Claims

1. A method for multiplexing CDMA and GPS searching, the method comprising:

selecting a search mode from a plurality of search modes for a plurality of communication protocols, the plurality of search modes being associated with different search processing for the plurality of communication protocols;

dynamically configuring channel search hardware to execute a plurality of independent searches including at least a first and second search modes utilizing respective first and second communication protocols, the channel search hardware comprises first hardware components allocated to both the first and second search modes, and second hardware components allocated to the second search mode, the first hardware components distinct from the second hardware components, the first search mode being a GPS mode and the second search mode being a CDMA mode, and in the first search mode the first hardware components are allocated to simultaneously perform the plurality of independent searches in parallel while the second hardware components are disabled, and in the second search mode the first hardware components and the second hardware components perform the independent searches in a time-multiplexed manner;

simultaneously executing the plurality of independent searches using the configured channel search hardware; and

configuring a demodulator of a wireless communication device as a function of results from the independent searches.

2. The method of claim 1, wherein each independent search is associated with a distinct set of search parameters.

3. The method of claim 2, wherein the search parameters comprise at least one of a window size, a coherent accumulation length, a non-coherent accumulation length, and a PN offset.

4. The method of claim 1, wherein configuring the demodulator as a function of the results from the independent searches comprises:

despreading received data;

generating a coherent accumulation result as a function of the despread data; and

configuring the demodulator as a function of the coherent accumulation result if the selected search mode is the first search mode.

5. The method of claim 1, wherein configuring the demodulator as a function of the results from the independent searches if the second search mode is selected comprises:

despreading received data;

generating coherent accumulation results as a function of the despread data;

computing energy values as a function of the coherent accumulation results;

generating non-coherent accumulation results as a function of the energy values;

identifying a plurality of energy peaks as a function of the non-coherent accumulation results;

sorting the plurality of energy peaks; and

configuring the demodulator as a function of the sorted energy peaks.

6. A method for multiplexing CDMA and GPS searching, the method comprising:

dynamically configuring channel search hardware to perform a plurality of simultaneously executed independent searches in one of a plurality of search modes for a plurality of communication protocols, the plurality of search modes comprising a GPS mode and CDMA mode utilizing respective first and second protocols, the channel search hardware comprises first hardware components allocated to both the GPS search mode and the CDMA search mode, and second hardware components allocated to the CDMA search mode, the first hardware components distinct from the second hardware components, wherein in the GPS mode the first hardware components are allocated to simultaneously perform the independent searches in parallel where the second hardware components are disabled, and in the CDMA mode the first hardware components and second hardware components perform the searches in a time-multiplexed manner;

for each independent search, despreading received data;

generating coherent accumulation results as a function of the despread data;

in the GPS mode, configuring a demodulator as a function of the coherent accumulation results; and

in the CDMA mode,

computing energy values as a function of the coherent accumulation results,

generating non-coherent accumulation results as a function of the energy values,

identifying a plurality of energy peaks as a function of the non-coherent accumulation results,

sorting the plurality of energy peaks, and

configuring the demodulator as a function of the sorted energy peaks.

7. The method of claim 6, wherein the received data comprises I and Q quadrature components of at least one of gain-adjusted I/Q data, center band I/Q data, lower band I/Q data, and higher band I/Q data.

8. A computer readable medium including computer executable instructions stored thereon for:

selecting a search mode from a plurality of search modes for a plurality of communication protocols, the plurality of search modes being associated with different search processing for the plurality of communication protocols;

dynamically configuring channel search hardware to execute a plurality of independent searches including at least a first and second search modes utilizing respective first and second communication protocols, the channel search hardware comprises first hardware components allocated to both the first and second search modes, and second hardware components allocated to the second search mode, the first hardware components distinct from the second hardware components, the first search mode being a GPS mode and the second search mode being a CDMA mode, and in the first search mode the first hardware components are allocated to simultaneously perform the plurality of independent searches in parallel where the second hardware components are disabled, and in the second search mode the first hardware components and the second hardware components perform the independent searches in a time-multiplexed manner;

simultaneously executing the plurality of independent searches using the configured channel search hardware; and

configuring a demodulator of a wireless communication device as a function of results from the independent searches,

wherein the computer readable medium is one of the following;

RAM, ROM, EEPROM, flash memory, fixed or removable disc media, including optical or magnetic media.

9. The computer readable medium of claim 8, wherein each independent search is associated with a distinct set of search parameters.

10. The computer readable medium of claim 9, wherein the search parameters comprise at least one of a window size, a coherent accumulation length, a non-coherent accumulation length, and a PN offset.

11. The computer readable medium of claim 8, including further instructions for:

despreading received data;

generating a coherent accumulation result as a function of the despread data; and

configuring the demodulator as a function of the coherent accumulation result if the selected search mode is the first search mode.

12. The computer readable medium of claim 8, including further instructions for configuring the demodulator as a function of the results from the independent searches if the second search mode is selected including:

despreading received data;

generating coherent accumulation results as a function of the despread data;

computing energy values as a function of the coherent accumulation results;

generating non-coherent accumulation results as a function of the energy values;

identifying a plurality of energy peaks as a function of the non-coherent accumulation results;

sorting the plurality of energy peaks; and

configuring the demodulator as a function of the sorted energy peaks.

13. A computer readable medium including computer executable instructions stored thereon for:

dynamically configuring channel search hardware to perform a plurality of simultaneously executed independent searches in one of a plurality of search modes for a plurality of communication protocols, the plurality of search modes comprising a GPS mode and a CDMA mode utilizing respective first and second protocols, the channel search hardware comprises first hardware components allocated to both the GPS search mode and the CDMA search mode, and second hardware components allocated to the CDMA search mode, the first hardware components distinct from the second hardware components, wherein in the GPS mode the first hardware components are allocated to simultaneously perform the independent searches in parallel where the second hardware components are disabled and in the CDMA mode the first hardware components and second hardware components perform the searches in a time-multiplexed manner;

for each independent search, using a matched filter to despread received data;

generating coherent accumulation results as a function of the despread data;

in the GPS mode, configuring a demodulator as a function of the coherent accumulation results; and

in the CDMA mode,

computing energy values as a function of the coherent accumulation results,

generating non-coherent accumulation results as a function of the energy values,

identifying a plurality of energy peaks as a function of the non-coherent accumulation results,

sorting the plurality of energy peaks, and

configuring the demodulator as a function of the sorted energy peaks,

wherein the computer readable medium is one of the following;

RAM, ROM, EEPROM, flash memory, fixed or removable disc media, including optical or magnetic media.

14. An apparatus for multiplexing CDMA and GPS searching, the apparatus comprising:

a channel search module configured to perform a plurality of simultaneously executed independent searches in one of a plurality of search modes for a plurality of communication protocols, the plurality of search modes comprising a GPS mode and a CDMA mode utilizing respective first and second communication protocols, the channel search module comprises first hardware components allocated to both the GPS mode and the CDMA mode, and second hardware components allocated to the CDMA mode, the first hardware components distinct from the second hardware components;

a control module to dynamically configure the channel search module as a plurality of simultaneously operating GPS channels in the GPS mode using the first hardware components while the second hardware components are disabled, and to dynamically reconfigure the channel search module as a plurality of time-multiplexed searcher time slices in the CDMA mode using the first hardware components and the second hardware components; and

a modem to demodulate a signal based on results from the searches, wherein the channel search module comprises a coherent accumulator arrangement configured to generate a coherent accumulation result in the CDMA mode and to generate a set of coherent accumulation results in the GPS mode.

15. The apparatus of claim 14, wherein the channel search module comprises a matched filter to despread received data, the matched filter comprising an adder arrangement configured to output a first sum in the GPS mode and a second sum in the CDMA mode.

16. The apparatus of claim 14, wherein the channel search module comprises a PN generator to generate a PN sequence in the CDMA mode and a set of PN sequences in the GPS mode.

17. The apparatus of claim 14, wherein the channel search module configures the modem as a function of the set of coherent accumulation results in the GPS mode.

18. An apparatus for multiplexing CDMA and GPS searching, the apparatus comprising:

means for selecting a search mode from a plurality of search modes for a plurality of communication protocols, the plurality of search modes being associated with different search processing for the plurality of communication protocols;

means for dynamically configuring channel search hardware to execute a plurality of independent searches including at least a first and second search modes utilizing respective first and second communication protocols, the channel search hardware comprises first hardware components allocated to both the first and second search modes, and second hardware components allocated to the second search mode, the first hardware components distinct from the second hardware components, the first search mode being a GPS mode and the second search mode being a CDMA mode, and in the first search mode the first hardware components are allocated to simultaneously perform the plurality of independent searches in parallel while the second hardware components are disabled, and in the second search mode the first hardware components and the second hardware components perform the independent searches in a time-multiplexed manner;

means for simultaneously executing the plurality of independent searches using the configured channel search hardware; and

means for configuring a demodulator of a wireless communication device as a function of results from the independent searches.

19. The apparatus of claim 18, wherein each independent search is associated with a distinct set of search parameters.

20. The apparatus of claim 19, wherein the search parameters comprise at least one of a window size, a coherent accumulation length, a non-coherent accumulation length, and a PN offset.

21. The apparatus of claim 18, wherein the means for configuring the demodulator as a function of the results from the independent searches comprises:

means for despreading received data;

means for generating a coherent accumulation result as a function of the despread data; and

means for configuring the demodulator as a function of the coherent accumulation result if the selected search mode is the first search mode.

22. The apparatus of claim 18, further comprising:

means for despreading received data;

means for generating coherent accumulation results as a function of the despread data;

means for computing energy values as a function of the coherent accumulation results;

means for generating non-coherent accumulation results as a function of the energy values;

means for identifying a plurality of energy peaks as a function of the non-coherent accumulation results; and

means for sorting the plurality of energy peaks;

wherein the demodulator is configured as a function of the sorted energy peaks if the selected search mode is the second search mode.

23. An apparatus for multiplexing CDMA and GPS searching, the apparatus comprising:

means for dynamically configuring channel search hardware to perform a plurality of simultaneously executed independent searches in one of a plurality of search modes for a plurality of communication protocols, the plurality of search modes comprising a GPS mode and a CDMA mode utilizing respective first and second protocols, the channel search hardware comprises first hardware components allocated to both the GPS search mode and the CDMA search mode, and second hardware components allocated to the CDMA search mode, the first hardware components distinct from the second hardware components, wherein in the GPS mode the first hardware components are allocated to simultaneously perform the independent searches in parallel where the second hardware components are disabled, and in the CDMA mode the first hardware components and second hardware components perform the searches in a time-multiplexed manner;

means for despreading received data for each independent search;

means for generating coherent accumulation results as a function of the despread data;

means for configuring a demodulator as a function of the coherent accumulation results in the GPS mode; and

means for, in the CDMA mode,

computing energy values as a function of the coherent accumulation results,

generating non-coherent accumulation results as a function of the energy values,

identifying a plurality of energy peaks as a function of the non-coherent accumulation results,

sorting the plurality of energy peaks, and

configuring the demodulator as a function of the sorted energy peaks.

24. The apparatus of claim 23, wherein the received data comprises I and Q quadrature components of at least one of gain-adjusted I/Q data, center band I/Q data, lower band I/Q data, and higher band I/Q data.