Telephone handset for operating in a plurality of wireless telephone system

• US 6,011,960 A
• Filed: 01/26/1996
• Issued: 01/04/2000
• Est. Priority Date: 11/25/1991
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Callahan, Kevin, Jacobs, Charles A., Yamada, Jun
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US08/592,000
• Time in Patent Office: 1,439 Days
• Field of Search: 379/58, 379/59, 455/33.1, 455/77, 455/552, 455/426, 455/435, 455/9, 455/551, 455/434, 455/553, 455/432, 370/329, 370/352, 370/337
• US Class Current: 455/77
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/0088 Scheduling hand-off measurements
• CPC Class Codes: H04W 36/1446 wherein at least one of the networks is unlicensed
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 8/22 Processing or transfer of terminal data, e.g. status or physical capabilities
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A personal communications system permits a wireless handset to access either a cellular mobile telephone system (CMTS) or a private wireless telephone system (WTS) which shares the CMTS frequency band by utilizing those CMTS channels which are idle in the area serviced by the WTS. The wireless handset automatically selects between the WTS and CMTS operating modes by maintaining a list of previously accessed WTS control channels and periodically scanning that list for a WTS available at the location of the handset. If a WTS control channel is not found in that list, then the handset periodically scans all possible WTS control channels for the purpose of registering on an available WTS. If no WTS is found, then the handset switches to CMTS mode. The scanning methodology permits the wireless handset to rapidly lock on to an available WTS which will provide service to the handset, so as to reduce the possibility of the wireless handset missing incoming paging signals.

Claims

1. A method for automatically selecting an operating mode for a dual-mode telephone handset adapted to operate in a cellular mobile telephone system (CTMS) and in at least one wireless telephone system (WTS), said at least one WTS having a WTS control unit and sharing the CMTS frequency band by utilizing for both WTS control channels and WTS voice channels those CMTS voice channels which are idle in the area serviced by said WTS, comprising the steps of:

(a) scanning with said telephone handset the CMTS voice channels on a list stored in said telephone handset, said list identifying WTS control channels previously accessed by said handset, to determine the presence of one or more WTS control channels in said areas;

(b) transmitting a registration request from said telephone handset to the control unit of said at least one WTS over said one or more WTS control channels,

(c) switching said handset to operate in said WTS mode on a WTS whose control unit has accepted said registration request;

(d) updating said list based upon a communication from said WTS control unit responsive to said registration request; and

(e) switching said handset to operate in said CMTS mode if said registration request is denied by the control unit of each of said at least one WTS.

2. The method of Claim 1 wherein said telephone handset further scans all CMTS channels which are also available to be used as WTS control channels, if a WTS control unit which will accept said registration request is not found after scanning the CMTS channels on said list.

3. The method of claim 1 wherein the step of transmitting said registration request to said WTS control unit via said WTS control channels on said list is performed in the order of decreasing received signal strength of said WTS control channels, whereby a registration request is first sent to the WTS control unit associated with the strongest WTS control channel.

4. The method of claim 1, further including the step of storing the channel numbers and system identifications (SIDs) of those WTS control units which deny registration requests to said telephone handset in said area.

5. The method of claim 4 wherein a registration request is not transmitted to any WTS control unit which has previously denied registration requests by said telephone handset in said area.

6. A telephone handset for operating in at least one wireless telephone system (WTS) which shares the frequency band of a cellular mobile operating telephone system (CMTS) by utilizing for both WTS control channels and WTS voice channels those CMTS voice channels which are idle in the area serviced by said WTS, comprising:

(a) means for maintaining a list of CMTS voice channels corresponding to WTS control channels most recently used by said handset to access said WTS;

(b) means for scanning said CMTS voice channels on said list to determine the presence of one or more WTS control channel in said area; and

(c) means for updating said list in response to communications over said one or more WTS control channels of said at least one WTS.

7. The telephone handset of claim 6, further including means for operating in said CMTS.

8. A telephone handset for operating in a plurality of wireless telephone systems (WTS) comprising:

(a) means for accessing an available WTS on idle voice channels of a cellular mobile telephone system (CMTS) which operate as WTS control channels,

(b) scanning means for scanning control channels of said accessed WTS, and

(c) channel table means for storing and dynamically updating a list of WTS control channels located by said scanning means, said handset utilizing said channel table means to maintain service in said accessed WTS in the presence of stronger control channel signals from others of said WTS'"'"'s whose service areas overlap at the location of said handset.

9. The telephone handset of claim 8 further including means for operating in a cellular mobile telephone system (CMTS).

10. A dual-mode telephone handset for operating in a cellular mobile telephone system (CMTS) and in at least one wireless telephone system (WTS), each WTS having a WTS control unit and sharing the CMTS frequency band by utilizing those CMTS voice channels which are idle in the area serviced by said at least one WTS as both WTS control and WTS voice channels, said telephone handset comprising:

(a) means for storing and maintaining a list of CMTS voice channels identifying WTS control channels most recently used by said handset to access said at least one WTS;

(b) means for scanning the CMTS channels in said list and determining therefrom the presence of one or more WTS control channels;

(c) means for scanning all of said idle CMTS voice channels and determining therefrom the presence of one or more WTS control channels in the event that no WTS control channels are identified by scanning the CMTS channels in said list;

(d) means for transmitting a registration request on said WTS control channels;

(e) means for receiving a registration acceptance or denial from said WTS control unit along said WTS control channels;

(f) control means for operating said handset in a WTS whose control unit has accepted said registration request, said control means operating said handset in said CMTS if said registration request is denied by each control unit of said at least one WTS; and

(f) means for updating said list based on a communication from said WTS control unit responsive to said registration request.

11. The telephone handset of claim 10 wherein said list identifies WTS control channels most recently accessed by said handset.

12. The telephone handset of claim 10 wherein said action comprises acceptance of said registration request.

13. The telephone handset of claim 10 wherein said action comprises denial of said registration request.

14. The telephone handset of claim 10 wherein said action comprises at least one of acceptance or denial of said registration request.