Method and apparatus for selecting a communication channel in a communication network

A method of prolonging battery life in a mobile communication device, comprising:

• acquiring at least one signal comprising at least one list of communication channels;
• selecting a communication channel for use from the at least one list, wherein selecting comprises optimizing the at least one list by eliminating channels having a received signal strength less than a first threshold and organizing the remaining channels according to the received signal strength and comparatively evaluating a last used channel and a last attempted channel and a best channel;
• background scanning channels, wherein channels having a received signal strength equal to or greater than a received signal strength of the selected channel plus at least one threshold signal strength are background scanned for a number of cycles, the number of cycles determined by a magnitude of the at least one threshold;
• and
• selectively controlling changes by the mobile communication terminal among the communication channels using the optimized list.

A computer readable medium containing executable instructions which, when executed in a processing system, causes the system to select a communication channel from a group of channels, the selection comprising:

• accessing a first list comprising a plurality of communication channels;
• scanning and measuring a first received signal strength of each channel in the first list;
• forming a second list comprising the channels of the first list having the first received signal strength equal to or greater than a first threshold signal strength;
• scanning and measuring a second received signal strength of each channel in the second list;
• ordering the second list in response to the second received signal strength;
• selecting a channel for communication by comparatively evaluating a last used channel and a last attempted channel and a best channel according to the second received signal strength, wherein the last attempted channel is a channel selected for communication over which communication is not established, wherein the best channel has the highest received signal strength in the second list;
• and
• performing a background scan during at least one evaluation period, the background scan comprising scanning and measuring the channels of a currently used channel list, monitoring for one sweep cycle communication channels of the currently used channel list having a received signal strength equal to or greater than a received signal strength of the selected channel plus a fourth threshold signal strength, and monitoring for two sweep cycles communication channels of the currently used channel list having a received signal strength equal to or greater than the received signal strength of the selected channel plus a better base threshold signal strength.

A portable device that selects a communication channel from a group of channels, the device comprising at least one processor coupled to a memory, a display, and at least one radio modem, the at least one processor capable of selecting a communication channel from a group of channels by:

• receiving a first list comprising a plurality of communication channels;
• scanning and measuring a first received signal strength of each channel in the first list;
• forming a second list comprising the channels of the first list having the first received signal strength equal to or greater than a first threshold signal strength;
• scanning and measuring a second received signal strength of each channel in the second list;
• ordering the second list in response to the second received signal strength;
• selecting a channel for communication by comparatively evaluating a last used channel and a last attempted channel and a best channel according to the second received signal strength, wherein the last attempted channel is a channel selected for communication over which communication is not established, wherein the best channel has the highest received signal strength in the second list;
• and
• performing a background scan during at least one evaluation period by scanning and measuring the channels of a currently used channel list, monitoring for one sweep cycle communication channels of the currently used channel list having a received signal strength equal to or greater than a received signal strength of the selected channel plus a fourth threshold signal strength, and monitoring for two sweep cycles communication channels of the currently used channel list having a received signal strength equal to or greater than the received signal strength of the selected channel plus a better base threshold signal strength.

The portable device of claimed, wherein the at least one processor is capable of selecting by:

• determining that the last used channel is absent from the second list;
• selecting the last attempted channel for communication when it is determined that the last attempted channel is in a first position of the second list;
• moving a second new channel into the first position of the second list when the second new channel has a received signal strength that exceeds the received signal strength of the last attempted channel by a third threshold signal strength;
• and
• selecting the second new channel for communication.

An apparatus for communicating among a network of base stations, the apparatus comprising at least one processor coupled to a memory, a display, and at least one radio modem, the apparatus further comprising:

• means for receiving a first list comprising a plurality of communication channels;
• means for scanning and measuring a first received signal strength of each channel in the first list;
• means for forming a second list comprising the channels of the first list having the first received signal strength equal to or greater than a first threshold signal strength;
• means for scanning and measuring a second received signal strength of each channel in the second list;
• means for ordering the second list in response to the second received signal strength;
• means for selecting a channel for communication by comparatively evaluating a last used channel and a last attempted channel and a best channel according to the second received signal strength, wherein the last attempted channel is a channel selected for communication over which communication is not established, wherein the best channel has the highest received signal strength in the second list;
• and
• means for performing a background scan during at least one evaluation period by scanning and measuring the channels of a currently used channel list, monitoring for one sweep cycle communication channels of the currently used channel list having a received signal strength equal to or greater than a received signal strength of the selected channel plus a third threshold signal strength, and monitoring for two sweep cycles communication channels of the currently used channel list having a received signal strength equal to or greater than the received signal strength of the selected channel plus a better base threshold signal strength.

An electromagnetic medium containing executable instructions which, when executed in a processing system, causes the system to select a communication channel from a group of channels, the selection comprising:

• accessing a first list comprising a plurality of communication channels;
• scanning and measuring a first received signal strength of each channel in the first list;
• forming a second list comprising the channels of the first list having the first received signal strength equal to or greater than a first threshold signal strength;
• scanning and measuring a second received signal strength of each channel in the second list;
• ordering the second list in response to the second received signal strength;
• selecting a channel for communication by comparatively evaluating a last used channel and a last attempted channel and a best channel according to the second received signal strength, wherein the last attempted channel is a channel selected for communication over which communication is not established, wherein the best channel has the highest received signal strength in the second list;
• and
• performing a background scan during at least one evaluation period, the background scan comprising scanning and measuring the channels of a currently used channel list, monitoring for one sweep cycle communication channels of the currently used channel list having a received signal strength equal to or greater than a received signal strength of the selected channel plus a second threshold signal strength, and monitoring for two sweep cycles communication channels of the currently used channel list having a received signal strength equal to or greater than the received signal strength of the selected channel plus a better base threshold signal strength.

A system comprising a plurality of base stations using a group of channels, the base stations communicating with at least one portable device that selects a communication channel from the group of channels, the portable device comprising at least one processor coupled to a memory, a display, and at least one radio modem, the at least one processor capable of selecting a communication channel from the group of channels by:

• receiving a first list comprising a plurality of communication channels;
• scanning and measuring a first received signal strength of each channel in the first list;
• forming a second list comprising the channels of the first list having the first received signal strength equal to or greater than a first threshold signal strength;
• scanning and measuring a second received signal strength of each channel in the second list;
• ordering the second list in response to the second received signal strength;
• selecting a channel for communication by comparatively evaluating a last used channel and a last attempted channel and a best channel according to the second received signal strength, wherein the last attempted channel is a channel selected for communication over which communication is not established, wherein the best channel has the highest received signal strength in the second list;
• and
• performing a background scan during at least one evaluation period by scanning and measuring the channels of a currently used channel list, monitoring for one sweep cycle communication channels of the currently used channel list having a received signal strength equal to or greater than a received signal strength of the selected channel plus a fourth threshold signal strength, and monitoring for two sweep cycles communication channels of the currently used channel list having a received signal strength equal to or greater than the received signal strength of the selected channel plus a better base threshold signal strength.

A method for reducing power consumption in a roaming portable communication device, comprising:

• generating a list of received signal strengths for at least one possible channel;
• identifying channels with a received signal strength above a threshold level;
• resampling received signal strengths of the identified channels;
• selecting a communication channel from the identified channels by comparing the received signal strength of a last used channel, an available last attempted channel, and a best channel having the highest resampled received signal strength of the identified channels;
• and
• performing a background scan during at least one evaluation period, the background scan comprising scanning and measuring channels of a currently used channel list, monitoring for one sweep cycle communication channels of the currently used channel list having a received signal strength equal to or greater than a received signal strength of the selected channel plus a first threshold signal strength, and monitoring for two sweep cycles communication channels of the currently used channel list having a received signal strength equal to or greater than the received signal strength of the selected channel plus a better base threshold signal strength.