Two-way radio communication system with max-minimum call assignment method

Claim 3

The method according to claim 1, wherein step (a) includes measuring the inbound link quality.

Claim 4

The method according to claim 1, wherein step (a) includes measuring the inbound and outbound link quality.

Claim 5

The method according to claim 1, wherein step (a) includes a multi-sectored antenna for noting which channels are presently in use and determining a set of eligible channels by noting which channels are presently idle.

Claim 6

The method according to claim 1, wherein step (a) includes measuring the carrier to interference ratio thereon.

Claim 7

The method according to claim 5, wherein said step of measuring the carrier to interference ratio includes utilizing low speed data.

Claim 8

The method according to claim 1, wherein step (a) includes measuring a tone using a method such as the SINAD method.

Claim 9

The method according to claim 1, wherein step (b) includes sequentially comparing the lowest quality factor for present subscribers on one channel to the lowest quality factor for present subscribers on another channel and storing the particular channel for which the lowest quality factor is maximum among these present subscribers.

Claim 10

The method according to claim 1, wherein step (b) includes comparing the quality factors of present subscribers to a preestablished threshold set according to the modulation parameters.

Claim 11

The method according to claim 9, wherein said preestablished threshold is approximately 25 dB.

Claim 12

The method according to claim 1, wherein step (c) includes first assignments.

Claim 13

The method according to claim 4, wherein step (c) includes first assignments and handoff assignments.

Claim 14

The method according to claim 1, wherein said satisfactory quality factor is at least 30 dB.

Claim 15

The method according to claim 1, wherein step (c) includes considering another request in queue if said previous request could not be assigned.

Claim 16

The method according to claim 14, wherein calls are queued according to Erlang-C discipline.

Claim 17

Control apparatus for a trunking communication system having a single centrally located control station for providing service via a limited number of channels to a plurality of subscribers, the apparatus comprising: subscriber stations having: (a) means for requesting a channel assignment from the central control station; (b) means responsive to an assigned channel signal to operate on said channel with variable power output and measure inbound and outbound link quality; (c) means for generating an end of information interchange signal at the conclusion thereof; and the central control station having: (a) means for determining a present channel, including means for identifying subscribers and means for establishing a minimum quality factor on each channel so as to establish at least one eligible channel for a requesting subscriber; (b) means for supervising channel activity comprising: means for comparing the present minimum quality factor for each channel with respect to other channels so as to establish eligible channels; means for assigning a requesting subscriber to any of said eligible channels which is above a given threshold value; means for controlling the power output of said subscribers; and (c) means for detecting an end of transmission or end of message signal from any subscriber and truncating the channel assignment in response thereto.

Claim 18

Control apparatus for a trunking communication system having a single centrally located control station for providing service via a limited number of channels to a plurality of subscribers, the apparatus comprising: subscriber stations having: (a) means for requesting a channel assignment from the central control station; (b) means responsive to an assigned channel signal to operate on said channel with variable power output and measure inbound and outbound link quality; (c) means for generating an end of information interchange signal at the conclusion thereof; and the central control station having: (a) means for determining a present channel, including means for identifying subscribers and means for establishing a minimum quality factor on each channel so as to establish at least one eligible channel for a requesting subscriber; (b) means for supervising channel activity comprising: means for comparing the present minimum quality factor for each channel with respect to other channels so as to establish eligible channels; means for assigning a requesting subscriber to any of said eligible channels which is above a given threshold value; means for controlling the power output of said subscribers; and (c) means for detecting an end of transmission or end of message signal from any subscriber and truncating the channel assignment in response thereto.

Claim 19

The control apparatus according to claim 16, wherein means for requesting a channel assignment includes transmitting a data word such as an unique subscriber identification signal in conjunction with the channel assignment request via a control channel.

Claim 20

The control apparatus according to claim 16, wherein means responsive to an assigned channel signal includes a transceiver changing operation from a given present channel to a newly assigned channel.

Claim 21

The control apparatus according to claim 16, wherein means for determining a present channel includes a memory device coupled to a receive signal strength indicator for noting which channels are presently in use and determining eligible channels by noting which channels are presently idle.

Claim 22

The control apparatus according to claim 16, wherein central control station channel supervising means comprises means such as a microprocessor, to predeterminedly prioritize subscribers' requests into a handoff queue having relatively high priority and a first assignment queue having relatively low priority, and means for considering channel requests in the relative order of priority.

Claim 23

The control apparatus according to claim 16, wherein the central control station includes a channel supervising means comprising means for determining a present channel by use of a multi-sectored antenna and an omni antenna, and means for determining when to switch to an omni coverage antenna for serving a given subscriber upon determining that said given subscriber is too close.

Claim 24

The apparatus according to claim 16, wherein said central control station includes means for indicating received signal strength within said means for determining a present channel.

Claim 25

The apparatus according to claim 16, wherein said means for comparing the present minimum quality factor includes a first comparator with a fixed threshold limit for ensuring that the requestor will not interfere with existing calls and a second comparator for ensuring that a channel is assigned which will provide the maximum amount of protection against adjacent channel interference above a predefined level.

Claim 26

In a communications trunking system having a single central controller and a plurality of identifiable subscriber radios, the central controller routing interchanged traffic between subscriber radios over a limited number of identify information channels, and control occuring on a control channel, each identifiable subscriber radio comprising: controllably tuned transceiver means for communication via a control channel or an assigned information channel to the central controller; control means within said subscriber radio for requesting a channel assignment, for providing a measure of part of an outbound link quality as communications link quality between the central controller and said radio, and responsive to an assigned channel signal from the central controller to operate on a given channel; and transceiver power output controlling means, coupled to said transceiver, for receiving a power output control signal from the central controller for changing power output on the asigned channel and response thereto.

Claim 27

In a communications trunking system having a single central controller and a plurality of identifiable subscriber radios, the central controller routing interchanged traffic between subscriber radios over a limited number of identify information channels, and control occuring on a control channel, each identifiable subscriber radio comprising: controllably tuned transceiver means for communication via a control channel or an assigned information channel to the central controller; control means within said subscriber radio for requesting a channel assignment, for providing a measure of part of an outbound link quality as communications link quality between the central controller and said radio, and responsive to an assigned channel signal from the central controller to operate on a given channel; and transceiver power output controlling means, coupled to said transceiver, for receiving a power output control signal from the central controller for changing power output on the asigned channel and response thereto.

Claim 28

The subscriber radio according to claim 24, wherein said transceiver means comprises a transmitter and receiver operative in a simplex mode.

Claim 29

The subscriber radio according to claim 24, wherein said transceiver means comprises a transmitter and receiver operative in a duplex mode.

Claim 30

The subscriber radio according to claim 24, wherein said control means within said subscriber radio comprises a logic unit having a microprocessor.

Claim 31

The subscriber radio according to claim 24, wherein said control means includes identification means, coupled to the transceiver means, for generating and sending a predetermined identification signal in conjunction with a request signal.

Claim 32

The subscriber radio according to claim 21, wherein control means includes end of transmission signaling means for notifying the central controller that said interchange traffic has concluded.

Claim 33

The subscriber radio according to claim 24, wherein said interchange traffic includes message trunked traffic and transmission trunked traffic thereon.

Claim 34

The subscriber radio according to claim 24, wherein said control means monitors inbound communications link quality on said control channel as well as on an assigned information channel.

Claim 35

The subscriber radio according to claim 30, wherein said link quality is monitored by means of a data signal, such as a low speed data stream on said assigned information channel.

Claim 36

The subscriber radio according to claim 24, wherein said transceiver power output controlling means is operative only on an assigned information channel.

Claim 37

The subscriber ratio according to claim 24, wherein said control means includes mode switch means controllable by the subscriber as well as by said central controller.

Claim 38

The subscriber radio according to claim 34, wherein said mode switch means includes an electronic switch for choosing between a transmission trunked and a message trunked mode of communicating said interchange traffic.

Claim 41

The method of claim 36, wherein said step (c) of comparing according to a first predetermined criteria includes comparing the received signal strength of said weakest subscribers to one another in order to find a strongest one of said weakest subscribers and a present channel associated therewith.

Claim 42

The method of claim 36, wherein said step (d) of selecting according to a second predetermined crietria includes selecting a channel on which an identified weakest subscriber exceeds a given threshold level.

Claim 43

The method of claim 37, wherein said step (f) includes the steps of: (f1) assigning a best one of said identified channels to the requestor when a plurality of identified channels have been identified that at least meet a predetermined criteria; otherwise (f2) delaying assigning a channel to the requestor at this time.