Multiple channel communications system

A multi-channel communications system comprising:

• a plurality of mobile units having communications channels and forms of identification;
• a plurality of tower sites having communications channels for communications with the mobile units;
• a plurality of dispatch agencies with forms of identification;
• a multi-channel controller connected to said tower sites and said dispatch agencies said multi-channel controller further comprising:
• a multi-agency router for routing messages between the mobile units and the dispatch agencies through the communications channels when the mobile units and the dispatch agencies have the same form of identification;
• and
• a load service for performing communications channel load monitoring, balancing, and failure monitoring.

A multi-channel communications system comprising:

• at least one mobile unit having a first communications channel and at least one form of identification;
• a first tower site in a geographic area having the first communications channel for communications with the mobile unit;
• at least one dispatch agency having at least one form of identification for use by the dispatch agency to identify the mobile unit for which the agency is responsible;
• and
• a multi-channel controller connected to the first tower site in a geographic area and to the dispatch agency for directing outgoing messages from the dispatch agency to the mobile unit and for routing incoming messages from the mobile unit to the dispatch agency according to the form of identification, for determining the first communications channel loading, for handing off the mobile unit from the first communications channel to a second communications channel at the tower site when loading on the first communications channel becomes excessive, for granting mobile unit requests to connect to another tower site in another geographic area when the geographic area covered by the first tower site is inadequate, and for routing outgoing and incoming messages to the second communications channel when communications fail on the first communications channel.

A method of controlling a multi-channel communications system comprising the steps of:

• analyzing messages from mobile units and dispatch agencies;
• resolving an identifier on the messages;
• routing the messages to the mobile units from a responsible dispatch agency and from the mobile units to the responsible agency according to the resolved identifier;
• adding the mobile units to communications channels as the mobile units begin communicating through a communications channel and removing mobile units by either one of time out of a multi-channel controller message timer or by direction of the responsible dispatch agency;
• and
• balancing loading on the communications channel said balancing performed by handing off the mobile unit to another communications channel as channel geographic coverage, loading conditions, and performance conditions change.

A method of routing a data message in a multi-channel communications system from a mobile unit to a dispatch agency comprising the steps of:

• determining if the mobile unit is listed in a routing table;
• routing the message to the dispatch agency destination if the mobile unit is listed in the routing table by performing the steps of:
• verifying if the data message is on a current communications channel listed in the routing table;
• determining if a communications channel change flag is set in the routing table;
• looking up a dispatch agency destination the message is to be sent to in the routing table if the channel change flag is not set;
• routing the message to the dispatch agency destination;
• otherwise notifying a load service that a channel change is sensed if the channel change flag is set;
• looking up a dispatch agency destination the message is to be sent to in the routing table;
• and
• routing the message to the dispatch agency destination;
• otherwise routing the message to the dispatch agency destination if the mobile unit is not listed in the routing table by performing the steps of:
• adding the mobile unit address to the routing table by address resolution and determining the dispatch agency the mobile unit belongs to;
• adding the mobile unit address to a multi-channel communications database and generating a log report;
• looking up a dispatch agency destination the message is to be sent to in the routing table;
• and
• routing the message to the dispatch agency destination.

A method of routing a message in a multi-channel communications system from a dispatch agency to a mobile unit comprising the steps of:

• determining if the message is for a poll rate increase;
• routing the message to the mobile unit if the message is not for a poll rate increase by performing the steps of:
• determining if a channel change flag is set in a routing table;
• providing a proper format for the message for a current channel if the channel change flag is not set;
• incrementing a packet counter for use in evaluating communications channel usage;
• routing the message to the mobile unit;
• otherwise providing a proper format for the message for a the current channel and a new channel if the channel change flag is set;
• routing the data packet to the current channel and a new channel;
• incrementing the packet counter for the new channel for evaluating communications channel usage;
• and
• routing the message to the mobile unit;
• otherwise routing the message to the mobile unit if the message is for a poll rate increase by performing the steps of:
• routing the message to a load service;
• generating a log report;
• generating a poll rate increase message;
• sending the poll rate increase message to a radio network controller for processing;
• and
• routing the poll rate increase message to the mobile unit.

A method of passive balancing mobile unit loading on communications channels of a multi-channel communications system employing time division multiple access where the mobile units operate at a predetermined polling rate comprising the steps of:

• determining the communications channels in use at a tower site;
• monitoring the loading on the communications channels;
• calculating loading metrics for the communications channels from the number of mobile units and the mobile unit polling rates;
• sending the loading metrics to the mobile units;
• adding mobile units to a first communications channel as the mobile units come into the multi-channel communication system;
• continuing the monitoring of the communications channels;
• determining if a second communications channel at the tower site has a lower load metric than the first communications channel when said first communications channel reaches an overload condition;
• commanding mobile units added to the first communications channel after the overload conditions has been reached to change channels to the second communications if the second communications channel is available;
• and
• allowing the mobile units added to the first communications channel after the overload condition has been reached to stay on the first communications channel if the second communications channel is not available.

A method of active balancing mobile unit loading on communications channels of a multi-channel communications system employing time division multiple access where the mobile units operate at a predetermined polling rate comprising the steps of:

• determining the communications channels in use at a tower site;
• monitoring the loading on the communications channels;
• calculating loading metrics for the communications channels from the number of mobile units and the mobile unit polling rates;
• sending the loading metrics to the mobile units;
• determining when the mobile unit polling rates are changed;
• determining if a second communications channel at the tower site has a lower load metric than the first communications channel when said first communications channel reaches an overload condition;
• commanding mobile units added to the first communications channel after the overload conditions has been reached to change channels to the second communications if the second communications channel is available;
• and
• allowing the mobile units added to the first communications channel after the overload condition has been reached to stay on the first communications channel if the second communications channel is not available.

A method of mobile unit communications channel monitoring and changing in a multi-channel communications system comprising the steps of:

• determining if there is a reason for a communications channel change from a current communications channel;
• monitoring the current communications channel for messages if there is no reason for the communications channel change;
• otherwise holding off sending queued messages until the communications channel change is complete if there is a reason for a channel change;
• determining the reason for communications channel change;
• switching to a commanded channel if the reason for change is a command from a multi-channel controller by performing the steps of:
• determining if the commanded channel is acquired;
• determining if a special acknowledgement signal has been received form the multi-channel controller in a predetermined time if the commanded channel has been acquired;
• saving the commanded channel as a last used channel if the special acknowledgment signal has been received;
• and
• monitoring the commanded channel for messages;
• otherwise switching to a commanded channel if the reason for change is that all channels on a first tower site are overloaded by performing the steps of:
• determining if there is a second tower site based on distance to said tower site;
• requesting a least loaded channel at the second tower site;
• sending a channel request message to a multi-channel controller;
• starting a message timer in the multi-channel controller;
• waiting for a response to the channel request message;
• receiving a denied message from the multi-channel controller before the message timer has timed out;
• returning to monitoring the current communications channel.
• otherwise receiving no response to the channel request message from the multi-channel controller when the message timer has timed out;
• incrementing a count in a retry counter in the multi-channel communications controller;
• resending the channel request message if the count in the retry counter is less than a predetermined number;
• returning to monitoring the current communications channel if the count in the retry counter is more than a predetermined number.
• otherwise receiving a grant message containing a new commanded channel from the multi-channel controller before the message timer has timed out;
• switching to the new commanded channel;
• determining if the commanded channel is acquired;
• determining if a special acknowledgment signal has been received form the multi-channel controller in a predetermined time if the commanded channel has been acquired;
• saving the commanded channel as a last used channel if the special acknowledgment signal has been received;
• and
• monitoring the commanded channel for messages.
• otherwise switching to a commanded channel if the reason for change is that all channels on a first tower site distance are out of range by performing the steps of:
• requesting a second tower site based on distance information;
• requesting a least loaded channel at the second tower site;
• sending a channel request message to a multi-channel controller;
• starting a message timer in the multi-channel controller;
• waiting for a grant message containing a new commanded channel;
• switching to the new commanded channel;
• determining if the commanded channel is acquired;
• determining if a special acknowledgment signal has been received form the multi-channel controller in a predetermined time if the commanded channel has been acquired;
• saving the commanded channel as a last used channel if the special acknowledgment signal has been received;
• and
• monitoring the commanded channel for multi-channel controller messages.

A method of mobile unit communications channel monitoring in a multi-channel communications system comprising the steps of:

• monitoring the commanded channel for multi-channel controller messages;
• updating a table with communications channel status and loading when a multi-channel controller message is received;
• checking the table for valid position and static data;
• calculating a distance to a tower site if the position and static data is valid;
• flagging the distance calculated as valid;
• determining from the distance calculated if the tower site is in range;
• marking the communications channels at the tower site as GO in a search table if the tower site is in range and NOGO in the search table if the tower site is out of range;
• reordering the search table in a proper search order;
• and
• determining if there is a reason for a communications channel change from a current communication channel.

A multi-channel communications system comprising:

• a plurality of communications channels;
• a plurality of mobile units for communicating over said communications channels said mobile units having forms of identification;
• a plurality of dispatch agencies for communicating over said communications channels said dispatch agencies having a forms of identification;
• and
• said mobile units communicating with said dispatch agencies over the communications channels according to the forms of identification.