Method and system for transmit frequency hopping

• US 7,606,291 B2
• Filed: 07/14/2006
• Issued: 10/20/2009
• 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.
• Primary Examiner(s): Odom; Curtis B
• Application Number:
  US11/457,565
• Publication Number:
  US 20080013600A1
• Time in Patent Office: 1,194 Days
• Field of Search: 375/132
• US Class Current: 375/132
• 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, wherein;

on the receive scanning,

scanning the set of frequency channels;

determining whether a frequency is an active frequency; and

and wherein;

if a push-to-talk (PTT) is not initiated within a 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.

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 scanning for a transmit frequency,

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

4. The method of claim 1, wherein an active frequency is a frequency channel that is in use, and an activity level identifies a useage of the active frequency.

5. The method of claim 1, 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.

6. The method of claim 5, further comprising:

if not,

resetting an activity counter for the active frequency, and

repeating the scanning of the set of frequency channels.

7. The method of claim 5, 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.

8. The method of claim 7, 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.

9. 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;

determining whether the PTT is Dressed 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;

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;

upon a completion of the transmitting,

repeating the scanning of the set of frequency channels; and

updating activity levels for active frequencies.

10. 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;

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,

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;

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

wherein the mobile device utilizes the transmit frequency hopping amongst a plurality of mobile devices which are in direct radio frequency communication without infrastructure support.

11. The mobile device of claim 10, 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.

12. The mobile device of claim 10, 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.