METHOD AND SYSTEM FOR TRANSMIT FREQUENCY HOPPING

• US 20080013600A1
• Filed: 07/14/2006
• Published: 01/17/2008
• Est. Priority Date: 07/14/2006
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Fudally, Scott A.
• Granted Patent: US 7,606,291 B2
• Time in Patent Office: Days
• US Class Current: 375/136
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services

Abstract

A mobile device (110) and combined method (400/500) for frequency hopping is provided. The frequency hopping can combine a receive scanning (400) with a scanning (500) for a transmit frequency for providing automated channel selection. The transmit scanning can include determining whether a push to talk (PTT) is pressed (501), and selecting a transmit frequency from a set of frequency channels (130) based on a measured activity (150) on the set of frequencies. If the PTT (240) is within the hang-time (504), a frequency that is currently active during the hangtime can be selected, else, a frequency having a lowest activity count (506) can be selected for transmitting a communication in response to the PTT.

Claims

1. A method for receive frequency hopping on a mobile device, comprising:

combining a receive scanning over a set of frequency channels with a scanning for a transmit frequency on the set of frequency channels for providing automated channel selection.

2. The method of claim 1, further comprising:

on a push-to-talk (PTT),

selecting a transmit frequency from the set of frequency channels based on a previously measured activity level for bypassing an interference on the set of frequency channels.

3. The method of claim 1, further comprising:

on the receive scanning,

scanning the set of frequency channels;

determining whether a frequency is an active frequency; and

assigning an activity level to the active frequency.

4. The method of claim 3, further comprising:

on the scanning for a transmit frequency,

selecting an active frequency having a lowest activity level measured during the receive scanning,

5. The method of claim 3, wherein an active frequency is a frequency channel that is in use, and an activity level identifies a useage of the active frequency.

6. The method of claim 3, wherein the set of frequency channels further comprises:

on the receive scanning,

determining whether the active frequency corresponds to a private line of the mobile device; and

if so, un-muting the mobile device on the active frequency for receiving incoming communication.

7. The method of claim 6, further comprising:

if not,

resetting an activity counter for the active frequency, and

repeating the scanning of the set of frequency channels.

8. The method of claim 6, further comprising:

on the receive scanning;

waiting for a predetermined amount of time after the un-muting; and

,

determining whether a PTT has been initiated within the predetermined amount of time.

9. The method of claim 8, further comprising:

if the PTT has been initiated within the predetermined amount of time,

holding the active frequency used during the receive scanning; and

,

on the scanning for a transmit frequency;

using the active frequency as a transmit frequency for transmitting a communication in response to the PTT.

10. The method of claim 5, further comprising:

if the PTT has not been initiated within the predetermined amount of time,

determining whether the active frequency remains active during the predetermined amount of time, and

if so,

determining whether the active frequency corresponds to a private line of the mobile device;

else,

repeating the scanning of the set of frequency channels.

11. A method for transmit frequency hopping, comprising:

determining whether a push to talk (PTT) is pressed; and

selecting a transmit frequency from a set of frequencies based on a measured activity on the set of frequencies.

12. The method of claim 11, further comprising

determining whether the PTT is pressed within a hang-time, and

if the PTT is within the hang-time,

selecting the frequency that is currently active during the hangtime,

else

selecting the frequency having a lowest activity count,

for transmitting a communication in response to the PTT.

13. The method of claim 12, further comprising:

determining whether the transmit frequency is an active frequency, and if so,

repeating the scanning of the set of frequency channels;

selecting the transmit frequency that has a next highest activity count, else,

transmitting the communication on the transmit frequency until the PTT is released.

14. The method of claim 12, further comprising:

upon a completion of the transmitting,

repeating the scanning of the set of frequency channels; and

updating activity levels for active frequencies.

15. A mobile device for transmit frequency hopping, comprising:

a receiver for performing a receive scanning on a set of frequency channels;

a transmitter coupled to the receiver for transmitting a communication on a frequency identified by the receiver; and

a processor coupled to the transmitter and receiver for combining the receive scanning with the transmitting for providing automated channel selection,

wherein on detecting a push-to-talk (PTT), the processor selects a transmit frequency from the set of frequency channels based on a measured activity on the set of channels.

16. The mobile device of claim 15, wherein the receiver:

scans the set of frequency channels;

determines whether a frequency is an active frequency; and

determines whether the active frequency corresponds to a private line.

17. The mobile device of claim 15, further comprising:

a counter for assigning an activity level to active frequencies;

a timer for determining whether a push to talk (PTT) is initiated within a hang-time; and

a comparator for selecting a transmit frequency based on an activity level measured during the receive scanning.

18. The mobile device of claim 17, wherein a plurality of mobile devices are in direct radio frequency communication without infrastructure support.

19. The mobile device of claim 15, wherein the mobile device is a cell phone, a personal digital assistant, a mobile communication device, a portable media player, an emergency communication device, a remote beacon device, or a communication radio.