Registration of radiotelephones in networked cellular radiotelephone systems

• US 4,775,999 A
• Filed: 12/07/1987
• Issued: 10/04/1988
• Est. Priority Date: 10/31/1986
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Williams, James M.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/131,297
• Time in Patent Office: 302 Days
• Field of Search: 379/57, 379/59, 379/60, 340/825.44, 455/33, 455/34, 455/54
• US Class Current: 455/435.1
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface

Abstract

Adjacent cellular systems (101-103) are interconnected to form a network providing telephone coverage to mobiles located throughout their combined coverage areas (111-113). Each networked cellular system (101-103) includes base sites (412, 414, 416) located in cells (402, 404, 406) and a control terminal (420) coupled by data and voice lines to the base sites, a telephone central office (422) and the other cellular systems. Each base site (412, 414, 416) includes a base site controller 950, a scanning receiver 910, signalling transceiver 912 and up to eight voice channel transceivers (901-908). As mobiles move about the networked coverage area (111-113), intrasystem handoffs are provided between cells of the same cellular system, and intersystem handoffs are provided between border cells of adjacent cellular systems. Mobiles are paged throughout the networked coverage area (111-113) in the paging area (121-136) in which the mobile last registered. Registration parameters are updated by the control terminal (420) and base sites (412, 414, 416) and sent to mobiles in the overhead message train. Mobiles automatically register in response to receipt of the overhead message train when moving between paging areas (121-136) according to the flow charts of FIGS. 5 and 6.

Claims

1. A method of registration for radiotelephones located in one of at least two radiotelephone systems, each radiotelephone system having a plurality of cells for providing radiotelephone service to a corresponding geographical area, each cell having paging/access and voice channels and a radio coverage area established by fixed site radios, and each radiotelephone transmitting a registration message in response to a registration enabling message transmitted on the paging/access channels by the fixed site radios, said method comprising the steps of:

assigning the same system identification number to each of the at least two radiotelephone systems;

establishing the same re-registration parameters for each of the at least two radiotelephone systems such that each radiotelephone registers at least once per day;

assigning groups of cells to different paging areas;

assigning an offset number to each paging area, different from that assigned to any adjacent paging area, where offset numbers are selected from a predetermined range of numbers;

generating a registration identification number for each paging area derived from the corresponding assigned offset number;

periodically transmitting on the paging/access channels by the fixed site radios in each cell a registration enabling message containing the corresponding registration identification number for the paging area in which the cell is located; and

transmitting a registration message from a radiotelephone when the received registration identification number differs from a previously received registration number by a predetermined amount.

2. The method according to claim 1, further including the steps of receiving registration messages from the radiotelephones, and transmitting a paging message to a radiotelephone on the paging/access channels by the fixed site radios in the paging area in which a registration messages was last received from the radiotelephone.

3. The method according to claim 1, further including the step of storing in each radiotelephone a value with a predetermined relationship to a previously received registration identification number and transmitting a registration message from the radiotelephone when the received registration identification number is greater than or equal to the stored value or is less than the stored value by a predetermined amount.

4. A method of paging radiotelephones located in one of at least two radiotelephone systems, each radiotelephone system having a plurality of cells for providing radiotelephone service to a corresponding geographical area, each cell having paging/access and voice channels and a radio coverage area established by fixed site radios, and each radiotelephone transmitting a registration message in response to a registration enabling message transmitted by the fixed site radios, said method comprising the steps of:

assigning the same system identification number to each of the at least two radiotelephone systems;

establishing the same re-registration parameters for each of the at least two radiotelephone systems such that each radiotelephone registers at least once per day;

assigning groups of cells to different paging areas;

transmitting a paging message to a radiotelephone on the paging/access channels by the fixed site radios in the paging area in which the radiotelephone last transmitted a registration message;

transmitting an acknowledgement message from a radiotelephone in response to a paging message; and

directing a radiotelephone to an adjacent paging area if the radiotelephone transmits an acknowledgement message in a paging area which did not transmit the paging message.

5. A method of registration for cellular radiotelephones located in one of at least two cellular radiotelephone systems, each cellular radiotelephone system having a plurality of cells for providing radiotelephone service to a corresponding geographical area, each cell having paging/access and voice channels and a radio coverage area established by fixed site radios, and each cellular radiotelephone transmitting a registration message in response to a registration enabling message transmitted on the paging/access channels by the fixed site radios, said method comprising the steps of:

assigning the same system identification number to each of the least two cellular radiotelephone systems;

establishing the same re-regsstration parameters for each of the least two cellular radiotelephone systems such that each cellular radiotelephone registers at least once per day;

assigning groups of cells to different paging areas;

assigning an offset number to each paging area, different from that assigned to any adjacent paging area, where offset numbers are selected from a predetermined range of numbers;

generating a registration identification number for each paging area derived from the corresponding assigned offset number;

periodically transmitting on the paging/access channels by the fixed site radios in each cell a registration enabling message containing the corresponding registration identification number for the paging area in which the cell is located; and

transmitting a registration message from a cellular radiotelephone when the received registration identification number differs from a previously received registration number by a predetermined amount.

6. The method according to claim 5, further including the steps of receiving registration messages from the cellular radiotelephones, and transmitting a paging message to a cellular radiotelephone on the paging/access channels by the fixed site radios in the paging area in which a registration message was last received from the cellular radiotelephone.

7. The method according to claim 5, further including the step of storing in each cellular radiotelephone a value with a predetermined relationship to a previously received registration identification number and transmitting a registration message from the cellular radiotelephone when the received registration identification number is greater than or equal to the stored value or is less than the stored value by a predetermined amount.