Patent US3898390A successfully refreshed from Google Patents.
US3898390A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple zone communications system and method
Assignee: Lockheed Martin Corp
•
Filing: 1973-05-15
•
Granted: 1975-08-05
•
Expires: 1993-05-15
Abstract
Abstract A method and system for more efficiently utilizing presently available and prospectively available two-way communication channels for communication between mobile telephones and either fixed telephones or mobile telephones. A large mobile telephone service area is divided into a plurality of smaller zones, and channels are assigned to the zones in a manner which permits the reuse of channels in zones on a non-interfering basis. A control signal is broadcast over a designated one of the channels assigned to each zone by equipment at a fixed station in each zone under the control of a central control unit. Each mobile telephone monitors one of the designated control channels in accordance with the signal reception characteristics thereof. When a call is placed over the designated control channel, a service or talking channel is assigned to serve the call and the mobile unit is remotely tuned to the assigned talking channel. Provision is made for using the designated control channel as a talking channel if necessary, for assigning additional channels to a fixed station on the basis of user density, and for maintaining communications between two parties as a mobile unit moves from one zone to another. A novel mobile telephone unit operable in accordance with the techniques of the present invention and providing simplified call placement and control is also disclosed.
Inventors
- 👤 Joel D Wells
- 👤 George F Mcclure
- 👤 Lionel D Freeman
- 👤 John R Endicott
- 👤 Marion L Cunningham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:06
CPC Classifications
H; H04; H04W; H04W72/00; H04W72/50; H04W72/54; H04W72/542; H04M; H04M1/00; H04M1/72; H04M1/724; H04W36/00; H04W36/08; H04W48/00; H04W48/20; H04W76/00; H04W76/10
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
201 words
A method for establishing telephone communications between a fixed station and a mobile unit within a service area comprising the steps of: a. establishing a plurality of overlapping zones which together define a service area, each of said zones including a fixed station serving that zone; b. assigning a plurality of commuNication channels to each of the fixed stations serving the zones, the plurality of channels assigned to fixed stations serving adjacent zones being noninterfering and at least some of the plurality of channels being assigned to more than one fixed station; c. initially monitoring, at the mobile unit, a predetermined one of the plurality of channels assigned to a first fixed station serving a first zone from which the mobile unit receives a signal having a received level above a predetermined value; d. determining that the monitored one of the plurality of channels has been assigned for two-way communications; and e. monitoring in response to the determination a predetermined one of the plurality of channels assigned to a second fixed station serving a zone other than the first zone served by the fixed station so that a call can be established between the second fixed station and the mobile unit.
Claim 2
Independent Claim
201 words
A method for establishing telephone communications between a fixed station and a mobile unit within a service area comprising the steps of: a. establishing a plurality of overlapping zones which together define a service area, each of said zones including a fixed station serving that zone; b. assigning a plurality of commuNication channels to each of the fixed stations serving the zones, the plurality of channels assigned to fixed stations serving adjacent zones being noninterfering and at least some of the plurality of channels being assigned to more than one fixed station; c. initially monitoring, at the mobile unit, a predetermined one of the plurality of channels assigned to a first fixed station serving a first zone from which the mobile unit receives a signal having a received level above a predetermined value; d. determining that the monitored one of the plurality of channels has been assigned for two-way communications; and e. monitoring in response to the determination a predetermined one of the plurality of channels assigned to a second fixed station serving a zone other than the first zone served by the fixed station so that a call can be established between the second fixed station and the mobile unit.
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein the service area is defined by a repeating pattern of seven overlapping zones, the same plurality of communication channels being assigned to the fixed stations serving corresponding zones in repeating pattern.
Claim 4
Dependent Claim
36 words
The method of claim 1 wherein the service area is defined by a repeating pattern of nineteen zones, the same plurality of communication channels being assigned to the fixed stations serving corresponding zones in repeating pattern.
Claim 5
Dependent Claim
42 words
The method of claim 3 wherein the zones overlap by an amount sufficient to permit the monitoring at any location in one zone of at least one of the plurality of the communication channels assigned to each of two different fixed stations.
Claim 6
Dependent Claim
75 words
The method of claim 1 including the steps of: transmitting a call-up signal between a fixed station and the mobile unit over the monitored one of the plurality of communication channels; and, assigning, over the monitored one of the plurality of channels, an available one of the remaining plurality of channels assigned to the fixed station for two-way radio communication thereover between the fixed station and the mobile unit in response to the call-up signal.
Claim 7
Dependent Claim
70 words
The method of claim 5 including the steps of: determining that none of the remaining plurality of channels assigned to the fixed station is available; and, assigning over the monitored one of the plurality of channels, an available one of the plurality of channels assigned to a fixing station serving an adjacent zone for two-way radio communication thereover between the fixed station serving the adjacent zone and the mobile unit.
Claim 8
Dependent Claim
60 words
The method of claim 5 including the steps of: determining that none of the remaining plurality of channels assigned to the fixed station is available; assigning another communication channel to the fixed station; and, assigning, over the monitored one of the plurality of channels, said another communication channel for two-way communication thereover between the fixed station and the mobile unit.
Claim 9
Dependent Claim
41 words
The method of claim 5 including the steps of: assigning the monitored one of the plurality of communication channels for two-way radio communication between the fixed station and the mobile unit when none of the remaining plurality of channels is available.
Claim 10
Independent Claim
111 words
A method for assigning a plurality of dual frequency communication channels to users in a mobile ratio telephone system comprising the steps of: a. transmitting a call request between a fixed station and a mobile unit over a predetermined one of the plurality of channels; b. assigning over the predetermined one of the plurality of channels an available one of the remaining plurality of channels for two-way radio communications thereover between the fixed station and the mobile unit; and, c. assigning the predetermined one of the plurality of channels for two-way radio communication between the fixed station and the mobile unit when none of the remaining plurality of channels is available.
Claim 11
Independent Claim
111 words
A method for assigning a plurality of dual frequency communication channels to users in a mobile ratio telephone system comprising the steps of: a. transmitting a call request between a fixed station and a mobile unit over a predetermined one of the plurality of channels; b. assigning over the predetermined one of the plurality of channels an available one of the remaining plurality of channels for two-way radio communications thereover between the fixed station and the mobile unit; and, c. assigning the predetermined one of the plurality of channels for two-way radio communication between the fixed station and the mobile unit when none of the remaining plurality of channels is available.
Claim 12
Independent Claim
158 words
A method for maintaining telephone communicatIons between a fixed station and a mobile unit engaged in an established call over a radio communication channel in one of a plurality of overlapping zones as the mobile unit changes zones comprising the steps of: a. monitoring the received signal level of the established call between a first fixed station and the mobile unit; b. detecting a drop in the monitored received signal level below a predetermined threshold level; c. generating a zone change request signal in response to the detected drop in received signal level, d. monitoring the signal level of transmissions from the mobile unit received at each of a plurality of fixed stations around the first fixed station in response to the zone change request signal; and, e. reestablishing the call between one of the plurality of monitoring fixed stations and the mobile unit in response to the monitoring of signal levels at the plurality of fixed stations.
Claim 13
Independent Claim
158 words
A method for maintaining telephone communicatIons between a fixed station and a mobile unit engaged in an established call over a radio communication channel in one of a plurality of overlapping zones as the mobile unit changes zones comprising the steps of: a. monitoring the received signal level of the established call between a first fixed station and the mobile unit; b. detecting a drop in the monitored received signal level below a predetermined threshold level; c. generating a zone change request signal in response to the detected drop in received signal level, d. monitoring the signal level of transmissions from the mobile unit received at each of a plurality of fixed stations around the first fixed station in response to the zone change request signal; and, e. reestablishing the call between one of the plurality of monitoring fixed stations and the mobile unit in response to the monitoring of signal levels at the plurality of fixed stations.
Claim 14
Dependent Claim
38 words
The method of claim 10 wherein the received signal level of the established call between the first fixed station and the mobile unit is first monitored by monitoring, at the mobile unit, transmissions from the first fixed station.
Claim 15
Dependent Claim
38 words
The method of claim 11 wherein the drop in monitored received signal level is detected at the mobile unit by comparing the signal level of the transmissions received from the first fixed station with the predetermined threshold level.
Claim 16
Dependent Claim
48 words
The method of claim 12 wherein the zone change request signal is generated by the mobile unit in response to the signal level comparison and including the step of transmitting the zone change request signal to the fixed station over the radio communication channel serving the established call.
Claim 17
Dependent Claim
36 words
The method of claim 13 wherein the call is reestablished between the mobile unit and the one of the plurality of fixed stations over a communication channel differing from the communication channel serving the established call.
Claim 18
Dependent Claim
32 words
The method of claim 13 wherein the call is reestablished between the mobile unit and the one of the plurality of fixed stations over the same communication channel serving the established call.
Claim 19
Dependent Claim
118 words
The method of claim 10 including the steps of: transmitting the zone change request signal to a central control terminal operatively connected to the first fixed station and each of the plurality of fixed stations; transmitting a vote request signal to each of the plurality of fixed stations around the first fixed station in response to the transmitted zone change request signal; receiving from each of the plurality of fixed stations a signal representative of monitored received signal level in response to the transmitted vote request signal; comparing the signals representative of monitored received signal level; and, reestablishing the call between the mobile unit and the one of the plurality of fixed stations in response to the comparison.
Claim 20
Dependent Claim
38 words
The method of claim 16 wherein the received signal level of the established call between the first fixed station and the mobile unit is first monitored by monitoring, at the mobile unit, transmission from the first fixed station.
Claim 21
Dependent Claim
36 words
The method of claim 17 wherein the call is reestablished between the mobile unit and the one of the plurality of fixed stations over a communication channel differing from the communication channel serving the established call.
Claim 22
Dependent Claim
32 words
The method of claim 17 wherein the call is reestablished between the mobile unit and the one of the plurality of fixed stations over the same communication channel serving the established call.
Claim 23
Dependent Claim
53 words
The method of claim 10 wherein the call is reestablished by: comparing the relative amplitudes of the received signal levels monitored at the plurality of fixed stations; and, reestablsihing the call between the mobile unit and the one of the fixed stations having an available communication channel and receiving the highest signal level.
Claim 24
Dependent Claim
97 words
The method of claim 10 wherein the call is reestablishEd by: comparing the relative amplitudes of the received signal levels monitored at the plurality of fixed stations; selecting the one of the fixed stations receiving the highest signal level for reestablishing the call; determining that none of the plurality of communication channels assigned to the selected one of the fixed stations is available; assigning another communication channel to the selected one of the fixed stations; and, reestablishing the call between the mobile unit and the selected one of the fixed stations over the assigned another communication channel.
Claim 25
Dependent Claim
74 words
the method of claim 10 wherein the call is reestablished by: comparing the signal levels received at the plurality of fixed stations with a predetermined threshold level; selecting the first one of the fixed stations having an available communication channel and receiving a signal level above the predetermined threshold for reestablishing the call; and reestablishing the call between the mobile unit and the selected first one of the fixed stations over the available channel.
Claim 26
Independent Claim
297 words
A method for maintaining telephone communications between a fixed station and a mobile unit in a plural zone system as the mobile unit changes zones comprising the steps of: a. establishing a plurality of overlapping zones which together define a service area, each of said zones including a fixed station; b. assigning a plurality of communications channels to each of the zones, the plurality of channels assigned to adjacent zones being non-interfering; c. establishing a call between a fixed station in a first zone and a mobile unit within a radio propagation contour defined by signal reception level around the fixed station in the first zone; d. assigning the established call to an available one of the plurality of channels assigned to the first zone for two-way radio communication between the fixed station therein and the mobile unit; e. monitoring the signal reception level of the radio signal from the mobile unit at the fixed station in the first zone as the mobile unit moves relative to the fixed station; f. initiating a zone change request in response to a drop in the signal reception level below a predetermined threshold at the fixed station in the first zone without regard to the actual location of the mobile unit; g. monitoring the signal reception level of the radio signal from the mobile unit at a plurality of fixed stations in a plurality of zones adjacent the first zone in response to the change request; and, h. reassigning the established call to an available one of the plurality of channels assigned to a selected one of the plurality of fixed stations in one of the zones adjacent to the first zone in response to the monitored signal reception levels without regard to the actual location of the mobile unit.
Claim 27
Independent Claim
297 words
A method for maintaining telephone communications between a fixed station and a mobile unit in a plural zone system as the mobile unit changes zones comprising the steps of: a. establishing a plurality of overlapping zones which together define a service area, each of said zones including a fixed station; b. assigning a plurality of communications channels to each of the zones, the plurality of channels assigned to adjacent zones being non-interfering; c. establishing a call between a fixed station in a first zone and a mobile unit within a radio propagation contour defined by signal reception level around the fixed station in the first zone; d. assigning the established call to an available one of the plurality of channels assigned to the first zone for two-way radio communication between the fixed station therein and the mobile unit; e. monitoring the signal reception level of the radio signal from the mobile unit at the fixed station in the first zone as the mobile unit moves relative to the fixed station; f. initiating a zone change request in response to a drop in the signal reception level below a predetermined threshold at the fixed station in the first zone without regard to the actual location of the mobile unit; g. monitoring the signal reception level of the radio signal from the mobile unit at a plurality of fixed stations in a plurality of zones adjacent the first zone in response to the change request; and, h. reassigning the established call to an available one of the plurality of channels assigned to a selected one of the plurality of fixed stations in one of the zones adjacent to the first zone in response to the monitored signal reception levels without regard to the actual location of the mobile unit.
Claim 28
Dependent Claim
24 words
The method of claim 23 wherein the signal reception level is monitored at the fixed stations within all zones adjacent to the first zone.
Claim 29
Dependent Claim
37 words
The method of claim 24 wherein the selected one of the plurality of fixed stations is the one of the plurality of fixed stations having an available channel and having the highest relative monitored signal reception level.
Claim 30
Independent Claim
176 words
A system for establishing telephone communications between a fixed station and a mobile unit within a service area comprising: a fixed station serving each of a plurality of overlapping zones which together define a service area and each having a plurality of communication channels assigned thereto, the plurality of channels assigned to fixed stations serving adjacent zones being noninterfering and at least some of the plurality of channels being common to more than one of said fixed stations; means at the mobile unit for initially monitoring a predetermined one of the plurality of channels assigned to a first one of said fixed stations from which the signal received has a signal level above a predetermined value; means for determIning that the monitored one of said plurality of channels has been assigned for two-way communications; and means responsive to said determining means for monitoring a predetermined one of the plurality of channels assigned to a second one of said fixed stations so that a call can be established between said second fixed station and the mobile unit.
Claim 31
Independent Claim
176 words
A system for establishing telephone communications between a fixed station and a mobile unit within a service area comprising: a fixed station serving each of a plurality of overlapping zones which together define a service area and each having a plurality of communication channels assigned thereto, the plurality of channels assigned to fixed stations serving adjacent zones being noninterfering and at least some of the plurality of channels being common to more than one of said fixed stations; means at the mobile unit for initially monitoring a predetermined one of the plurality of channels assigned to a first one of said fixed stations from which the signal received has a signal level above a predetermined value; means for determIning that the monitored one of said plurality of channels has been assigned for two-way communications; and means responsive to said determining means for monitoring a predetermined one of the plurality of channels assigned to a second one of said fixed stations so that a call can be established between said second fixed station and the mobile unit.
Claim 32
Dependent Claim
51 words
The system of claim 26 wherein said fixed stations are a multiple of seven repeating overlapping zones; and, wherein the plurality of communication channels assigned to each of said fixed stations is common to the one of said fixed stations in corresponding zones in the repeating pattern of seven overlapping zones.
Claim 33
Dependent Claim
53 words
The system of claim 26 wherein the service area is defined by a repeating pattern of nineteen zones; and, wherein the plurality of communication channels assigned to one of said fixed stations is common to the one of said fixed stations located in the corresponding zone in the repeating pattern of nineteen zones.
Claim 34
Dependent Claim
45 words
The system of claim 28 wherein the overlap in each zone is sufficient to permit the monitoring at any location in each zone of at least one of the plurality of the communication channels assigned to each of two different ones of said fixed stations.
Claim 35
Dependent Claim
75 words
The system of claim 26 further comprising: means for transmitting a call-up signal between each of said fixed stations and a mobile unit over the monitored one of the plurality of communication channels; and, means for assigning, over the monitored one of the plurality of channels, an available one of the remaining plurality of channels assigned to the fixed station called for two-way radio communication thereover between the called fixed station and the mobile unit.
Claim 36
Dependent Claim
77 words
A system of claim 30 further comprising: means for determining that none of the remaining plurality of channels assigned to the called fixed station is available for the establishment of two-way radio communications; and, means for assigning, over the monitored one of the plurality of channels, an available one of the plurality of channels assigned to the adjacent one of said fixed stations for two-way radio communication thereover between said adjacent fixed station and the mobile unit.
Claim 37
Dependent Claim
73 words
The system of claim 30 including: means for determining that none of the remaining plurality of channels assigned to the called one of said fixed stations is available; means for assigning additional communication channels to each of said fixed stations; and means for assigning, over the monitored one of the plurality of channels, said another communication channel for two-way communication thereover between the called one of said fixed stations and the mobile unit.
Claim 38
Dependent Claim
44 words
The system of claim 30 including: means for assigning the monitored one of the plurality of communication channels for two-way radio communication between the called one of said fixed stations and the mobile unit when none of the remaining plurality of channels is available.
Claim 39
Independent Claim
109 words
A system for assigning a plurality of dual frequency communication channels to users in a mobile radiotelephone system comprising: a fixed station, a mobile unit, means for transmitting a call request between said fixed station and said mobile unit over a predetermined one of a plurality of dual frequency communication channels; means for assigning over said predetermined channel an available one of the remaining channels for two-way radio communication thereover between said fixed station and said mobile unit; and, means for assigning said predetermined channel for two-way radio communication between said fixed station and said mobile unit when none of the remaining channels is available for two-way radio communication.
Claim 40
Independent Claim
109 words
A system for assigning a plurality of dual frequency communication channels to users in a mobile radiotelephone system comprising: a fixed station, a mobile unit, means for transmitting a call request between said fixed station and said mobile unit over a predetermined one of a plurality of dual frequency communication channels; means for assigning over said predetermined channel an available one of the remaining channels for two-way radio communication thereover between said fixed station and said mobile unit; and, means for assigning said predetermined channel for two-way radio communication between said fixed station and said mobile unit when none of the remaining channels is available for two-way radio communication.
Claim 41
Independent Claim
146 words
A system for maintaining telephone communications between a fixed station and a mobile unit engaged in an established call over a radio communication channel in one of a plurality of overlapping zones as the mobile unIt changes zones comprising: a mobile unit; a first fixed station; a second fixed station; means for monitoring the received signal level of the established call between said first fixed station and said mobile unit and for detecting a drop in the monitored received signal level below a predetermined threshold level; means responsive to said monitoring means for generating a zone change request signal; means at said second fixed station for monitoring the signal level of transmissions received from said mobile unit responsively to said zone change request signal; and, means for reestablishing the call between said second fixed station and said mobile unit responsively to said signal level monitoring means.
Claim 42
Independent Claim
146 words
A system for maintaining telephone communications between a fixed station and a mobile unit engaged in an established call over a radio communication channel in one of a plurality of overlapping zones as the mobile unIt changes zones comprising: a mobile unit; a first fixed station; a second fixed station; means for monitoring the received signal level of the established call between said first fixed station and said mobile unit and for detecting a drop in the monitored received signal level below a predetermined threshold level; means responsive to said monitoring means for generating a zone change request signal; means at said second fixed station for monitoring the signal level of transmissions received from said mobile unit responsively to said zone change request signal; and, means for reestablishing the call between said second fixed station and said mobile unit responsively to said signal level monitoring means.
Claim 43
Dependent Claim
25 words
The system of claim 35 wherein said established call monitoring means includes means at said mobile unit for monitoring transmissions from said first fixed station.
Claim 44
Dependent Claim
32 words
The system of claim 36 wherein said established call monitoring means includes means for comparing the signal level of the transmissions received from said first fixed station with the predetermined threshold level.
Claim 45
Dependent Claim
51 words
The system of claim 37 wherein said zone change request signal generating means is responsive to said signal level comparing means and includes means for transmitting said zone change request signal to said second fixed station over the radio communication channel serving the established call and through said first fixed station.
Claim 46
Dependent Claim
32 words
The system of claim 38 wherein the channel over which the call is reestablished between said mobile unit and said second fixed station differs from the communication channel serving the established call.
Claim 47
Dependent Claim
35 words
The system of claim 38 wherein the channel over which the call is reestablished between said mobile unit and said second fixed station is the same communication channel as the channel serving the established call.
Claim 48
Independent Claim
304 words
A system for maintaining telephone communications between a fixed station and a mobile unit in a plural zone system as the mobile unit changes zones comprising: a plurality of fixed stations each located in one of a plurality of overlapping zones which together define a service area, each of said fixed stations including means for transmitting on a plurality of communications channels noninterfering with the plurality of channels of adjacent fixed stations; a mobile unit; means for establishing a call between one of said fixed stations in a first zone and said mobile unit within a radio propagation contour defined by signal reception level around said first zone fixed station; means for assigning said established call to an available one of the plurality of channels of said first zone fixed station for two-way radio communication between said first zone fixed station and said mobile unit; means for monitoring the signal reception level of the radio signal from said mobile unit at said first zone fixed station as said mobile unit moves relative to said first zone fixed station; means for initiating a zone change request in response to a drop in the signal reception level below a predetermined threshold at the fixed station in the first zone without regard to the actual location of the mobile unit; means for monitoring the signal reception level of the radio signal from the mobile unit at a plurality of fixed stations in a plurality of zones adjacent the first zone in response to the change request; and, means for reassigning the established call to an available one of the plurality of channels of a selected one of said plurality of fixed stations in adjacent zones in response to the monitored signal reception levels in said adjacent zones without regard to the actual location of the mobile unit.
Claim 49
Independent Claim
304 words
A system for maintaining telephone communications between a fixed station and a mobile unit in a plural zone system as the mobile unit changes zones comprising: a plurality of fixed stations each located in one of a plurality of overlapping zones which together define a service area, each of said fixed stations including means for transmitting on a plurality of communications channels noninterfering with the plurality of channels of adjacent fixed stations; a mobile unit; means for establishing a call between one of said fixed stations in a first zone and said mobile unit within a radio propagation contour defined by signal reception level around said first zone fixed station; means for assigning said established call to an available one of the plurality of channels of said first zone fixed station for two-way radio communication between said first zone fixed station and said mobile unit; means for monitoring the signal reception level of the radio signal from said mobile unit at said first zone fixed station as said mobile unit moves relative to said first zone fixed station; means for initiating a zone change request in response to a drop in the signal reception level below a predetermined threshold at the fixed station in the first zone without regard to the actual location of the mobile unit; means for monitoring the signal reception level of the radio signal from the mobile unit at a plurality of fixed stations in a plurality of zones adjacent the first zone in response to the change request; and, means for reassigning the established call to an available one of the plurality of channels of a selected one of said plurality of fixed stations in adjacent zones in response to the monitored signal reception levels in said adjacent zones without regard to the actual location of the mobile unit.
References Cited (Backward Citations)
US2694141A
Cited
US3590166A
Cited
US3539924A
Cited
US3588371A
Cited
US3663762A
Cited
US3764915A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |