Reference Oscillator Arbitration and Scheduling for Multiple Wireless Subsystems

• US 20130115905A1
• Filed: 05/04/2012
• Published: 05/09/2013
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Nikolaos Haralabidis
• Inventors: HARALABIDIS, Nikolaos
• Granted Patent: US 9,197,278 B2
• Time in Patent Office: Days
• US Class Current: 455/259
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 2215/065 by changing the frequency of clock or reference frequency

Abstract

Systems and methods are described for controlling a reference oscillator shared by multiple subsystems of a communications system and arbitrating usage of the reference oscillator among these subsystems. By changing the properties of the reference oscillator (e.g., by tuning the reference oscillator) according to the needs of particular subsystem(s), the communications system can configure the reference oscillator to meet the specification requirements of these particular subsystem(s) and can later reconfigure the reference oscillator to meet the needs of other subsystems. Further, the controller can configure the subsystems based on parameters that impact multiple subsystems (e.g., by implementing geographic awareness, spectrum occupation awareness, and availability of Assisted GPS (AGPS) functionality) to achieve further optimization of the communications system.

Claims

1. A communications system comprising:

a plurality of subsystems;

a reference oscillator coupled to the subsystems, wherein the reference oscillator is configured to provide a reference signal to the subsystems; and

a controller coupled to the reference oscillator and the subsystems, wherein the controller is configured to;

receive, from a first subsystem in the plurality of subsystems, a request to change a characteristic of the reference oscillator;

determine, based on a priority of the request, whether to process the request;

initiate, in response to determining that the request should be processed, a reconfiguration of the reference oscillator to meet preferred requirements of the first subsystem.

2. The system of claim 1, wherein the controller is further configured to send a notification to the subsystems of an upcoming change to characteristics of the reference oscillator prior to initiating the reconfiguration of the reference oscillator.

3. The system of claim 2, wherein the subsystems are configured to adjust their internal circuitry to compensate for the upcoming change to the characteristics of the reference oscillator in response to receiving the notification.

4. The system of claim 2, wherein the subsystems are configured to temporarily deactivate in response to receiving the notification.

5. The system of claim 1, wherein the request contains information regarding the preferred characteristics of the reference oscillator.

6. The system of claim 1, wherein the first subsystem is a cellular subsystem, and wherein the communications system is implemented on a cellular handset.

7. The system of claim 1, wherein the subsystems comprise:

a Global Positioning System (GPS) subsystem;

a wireless local area network (WLAN) subsystem;

a Bluetooth subsystem; and

a near field communications (NFC) subsystem.

8. The system of claim 1, wherein the controller is further configured to:

detect a change in a geographic location of the communications system;

determine a new configuration for the reference oscillator based on a current geographic location of the communications system;

notify the subsystems of an upcoming change to the configuration of the reference oscillator; and

initiate the reconfiguration of the reference oscillator to the new configuration.

9. The system of claim 8, wherein the controller is further configured to:

perform a scan for available cellular networks after a wake-up of the communications system has been initiated;

receive information from the available cellular networks; and

detect the change in the geographic location of the communications system based on the information from the available cellular networks.

10. The system of claim 1, wherein the controller is further configured to:

determine whether a frequency used for communications of a second subsystem conflicts with frequency requirements for the first subsystem; and

reconfigure the second subsystem if the frequency used for communications of the second subsystem conflicts with frequency requirements for the first subsystem.

11. The system of claim 10, wherein the controller is further configured to reconfigure the second system by assigning a smaller frequency range to the second subsystem.

12. The system of claim 10, wherein the controller is further configured to reconfigure the second system by assigning second time slots to the second subsystem that do not coincide with first time slots assigned to the first subsystem.

13. The system of claim 10, wherein the controller is further configured to reconfigure the second system by assigning second time slots to the second subsystem, and wherein the second time slots coincide with discontinued reception/transmission (DRX/DTX) gaps encountered by the first subsystem.

14. The system of claim 1, wherein the controller is further configured to:

determine whether Assisted GPS (AGPS) support is available to the communications system; and

in response to determining that AGPS support is available;

initiate a switch to AGPS for location detection functionality of the communications system, and

reconfigure the subsystems based on the switch to AGPS.

15. A method comprising:

receiving, from a first subsystem of a plurality of subsystems of a communications system, a request to change a characteristic of a reference oscillator;

determining, based on a priority of the request, whether to process the request; and

in response to determining that the request should be processed;

sending a notification to the subsystems of an upcoming change to characteristics of the reference oscillator, and

initiating a reconfiguration of the reference oscillator to meet preferred requirements of the first subsystem.

16. The method of claim 15, further comprising:

detecting a change in a geographic location of the communications system;

determining a new configuration for the reference oscillator based on a current geographic location of the communications system;

notifying the subsystems of an upcoming change to the configuration of the reference oscillator; and

initiating the reconfiguration of the reference oscillator to the new configuration.

17. The method of claim 15, further comprising:

determining whether a frequency used for communications of a second subsystem conflicts with frequency requirements for the first subsystem; and

assigning a smaller frequency range to the second subsystem if the frequency used for communications of the second subsystem conflicts with frequency requirements for the first subsystem.

18. The method of claim 15, further comprising:

determining whether a frequency used for communications of a second subsystem conflicts with frequency requirements for the first subsystem; and

assigning second time slots to the second subsystem that do not coincide with first time slots assigned to the first subsystem if the frequency used for communications of the second subsystem conflicts with frequency requirements for the first subsystem.

19. The method of claim 15, further comprising:

determining whether Assisted GPS (AGPS) support is available to the communications system; and

in response to determining that AGPS support is available;

initiating a switch to AGPS for location detection functionality of the communications system, and

reconfiguring the subsystems based on the switch to AGPS.

20. A communications device comprising:

a plurality of wireless subsystems;

a reference oscillator coupled to the wireless subsystems, wherein the reference oscillator is configured to provide a reference signal to the wireless subsystems; and

a controller coupled to the reference oscillator and the subsystems, wherein the controller is configured to;

receive, from the subsystems, a plurality of requests to change a frequency of the reference oscillator;

prioritize the requests;

select, based on a priority of the request, a first request;

determine, based on the frequency of the reference oscillator, whether to process the request;

in response to determining that the first request should be processed;

send a notification to the subsystems of an upcoming change to the characteristics of the reference oscillator, and

initiate a first reconfiguration of the reference oscillator to meet preferred requirements of the first subsystem; and

initiate a second reconfiguration of the reference oscillator to adjust the frequency of the reference oscillator to a nominal value in response to determining that all requests in the plurality of requests have been processed.