Cellular telephone for monitoring analog and digital control channels

• US 5,420,911 A
• Filed: 10/04/1993
• Issued: 05/30/1995
• Est. Priority Date: 08/29/1991
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Mueller, Walter G. A., Ghisler, Walter, Dahlin, Jan E. A. S.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Bost, Dwayne D.
• Application Number:
  US08/132,163
• Time in Patent Office: 603 Days
• Field of Search: 379/58-61, 379/63, 455/33.1, 455/34.1, 455/34.2, 455/38.3, 455/88, 455/89, 455/90, 455/127, 455/343, 370/94.1, 370/95.1
• US Class Current: 455/553.1
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention is directed to a cellular mobile radio telephone system in which mobile stations may select either analog or digital control channels. Analog and dual-mode mobile stations are equipped to become multi-mode mobile stations which monitor both analog and digital control channels depending on the selected mode. Downlink multi-mode mobile stations, while required to use analog control channels for call access, may nonetheless scan digital control and paging channels to receive downlink control and paging communications from the land-based system. Bi-directional multi-mode mobile stations have the same capabilities as downlink mobiles but also are equipped to transmit control information to the land station over the uplink digital control channel. If no digital control channel is available, the multi-mode mobile stations scan primary and secondary sets of analog control channels. In this way, analog and dual-mode mobile stations may benefit from the advantages of monitoring digital control channels and digital paging channels including multiple pages per channel and battery-saving capabilities.

Claims

1. A multi-mode mobile radio telephone station for communicating over analog or digital traffic channels and control communications over an analog or a digital control channel and for interacting with a plurality of base stations where at least some of said base stations conduct control communications with said mobile station over said analog control channel and at least some of said base stations conduct control communications with said mobile station over said digital control channel, said mobile station comprising:

(a) a mode selection switch for switching said mobile station between an analog mode and a digital mode, said switch being initially set to its digital mode for receiving digital control communications over said digital control channel from one of said base stations.;

(b) means for scanning a set of digital control channels, received from said digital control communications when said mobile station is switched to a digital mode;

(c) first overhead message receiving means for determining if one of said digital control channels is available;

(d) means for conducting control communications with one of said base stations over a digital control channel associated with this base station if said one of the digital control channels is available;

(e) means for scanning a first set of analog control channels if none of said digital control channels is available;

(f) second overhead message receiving means for determining if one of said analog control channels is available; and

(g) means for conducting control communications with one of said base stations over an analog control channel associated with this base station if said one of the analog control channels is available.

2. A multi-mode mobile radio telephone station for interacting with a plurality of base stations where at least some of said base stations conduct control communications with said mobile station over analog control channels and at least some of said base stations conduct control communications with said mobile station over digital control channels, said mobile station comprising:

a mode selection switch for switching said mobile station between an analog mode and a digital mode;

means for conducting control communications with one of said base stations over an analog control channel associated with this base station when said mobile station is switched to an analog mode;

means for conducting control communications with one of said base stations over a digital control channel associated with this base station when said mobile station is switched to a digital mode;

means for scanning a set of digital control channels,

overhead message receiving means for determining if one of said digital control channels is available;

means for scanning a first set of analog control channels if none of said digital control channels is available;

detecting means, connected to said first set of analog control channel scanning means, for detecting at least one indicating bit which indicates whether or not a first preferred transmission system has digital traffic channel capabilities;

means for scanning a set of primary analog paging channels in response to said indicating bit indicating that said first preferred transmission system has digital traffic channel capabilities; and

means for scanning a second set of analog control channels in response to said indicating bit indicating that said first preferred transmission system does not have digital traffic channel capabilities.

3. A system according to claim 2, said mobile station further comprising:

means for receiving overhead messages over said first or second set of analog control channels, and

means for scanning control channels associated with a non-preferred transmission system in the event that an overhead message is not received from either said first or said second set of analog control channels.

4. In a cellular communications system for communicating over analog and digital traffic channels and having at least one multi-mode mobile radio telephone station and a plurality of base stations wherein control communications may be conducted over analog control channels and digital control channels, a method comprising:

(a) switching said mobile station to a digital mode;

(b) initiating control communications with a base station over one of said digital control channels, by scanning a set of digital control channels to determine if one of said digital control channels is available;

(c) conducting control communications over a digital control channel associated with this base station if said one of the digital control channels of said base station is available;

(d) initiating control communications with said base station over one of said analog control channels by scanning a first set of analog control channels when none of said digital control channels is available, after switching said mobile station to an analog mode; and

(e) conducting control communications with one of said base stations over an analog control channel associated with this base station if said one of the analog control channels is available;

wherein an available analog or digital control channel is used to assign the analog and digital traffic channels.

5. A cellular radio telephone communications system, comprising:

a mobile switching center;

plural base stations connected to said mobile switching center, for receiving and transmitting speech information and control information; and

plural mobile radio telephone stations, including at least one multi-mode mobile station including;

means for receiving speech and data information from a first base station over a voice channel;

means for transmitting speech and data information to said first base station over said voice channel;

means for receiving and decoding control information in an analog format from said first base station over a first control channel; and

means for receiving and decoding control information in a digital format from said first base station over a second control channel;

wherein said first base station transmits said control information in a digital format over said second control channel through a series of time frames, and each mobile station only monitors said control information over said second control channel during one of said time frames associated with said mobile station,

wherein each mobile station is assigned a mobile identification number and a portion of said number defines its associated time frame.

6. A cellular radio telephone communications system, comprising:

a mobile switching center;

plural base stations connected to said mobile switching center, for receiving and transmitting speech information and control information; and

plural mobile radio telephone stations, including at least one multi-mode mobile station including;

means for receiving speech and data information from a first base station over a voice channel;

means for transmitting speech and data information to said first base station over said voice channel;

means for receiving and decoding control information in an analog format from said first base station over a first control channel; and

means for receiving and decoding control information in a digital format from said first base station over a control channel;

wherein said first base station transmits said control information in a digital format over said control channel through a series of time frames, and each mobile station only monitors said control information over said control channel during one of said time frames associated with said mobile station,

wherein during time frames other than said associated time frame, said mobile station deactivates to conserve power.

7. A cellular communications system for accommodating radio communication between multi-mode mobile stations on analog or digital traffic channels and using digital and analog control channels and a plurality of base stations, where at least some of said base stations conduct control communications over analog control channels and at least some of said base stations conduct control communications over digital control channels, each of said mobile stations comprising:

means for scanning a set of digital control channels to detect if any such digital control channel is being transmitted from an associated base station;

means for determining if a recognizable overhead message is received by said mobile station on said digital control channel;

means for scanning a set of digital paging channels if said overhead message is received; and

means for scanning a set of primary analog control channels if said recognizable overhead message is not received,

wherein said base stations may transmit control information over analog control channels or digital control channels, and wherein an available analog or digital control channel is used to assign the analog and digital traffic channels.

8. The system according to claim 7, wherein said multi-mode mobile stations switched to an analog mode monitor analog control channel communications from said base stations and said multi-mode mobile stations switched to a digital mode monitor digital control channel communications from said base stations.

9. The system according to claim 7, wherein downlink multi-mode mobile stations have means for receiving control information on said digital control channel.

10. The system according to claim 7, wherein bi-directional multi-mode mobile stations have means for receiving and transmitting control information on said digital control channel.

11. The system according to claim 7, wherein said digital control and paging channels are assigned time slots on the same frequency.

12. The system according to claim 7, each of said multi-mode mobile stations conducting control communications over said digital control channels further comprising:

means for periodically scanning paging information on said digital paging channels for a predetermined number of digits, said predetermined number being substantially less than a total number of digits in said paging information;

means for comparing said predetermined number of digits to corresponding digits of an identification code associated with each mobile station;

means for deactivating mobile station power if an output signal from said comparing means indicates that there was no match between the predetermined number of digits and the corresponding identification code digits; and

means for periodically reactivating mobile station power and scanning said set of digital control channels.

13. A cellular communications system for accommodating radio communication between multi-mode mobile stations using digital and analog control channels and a plurality of base stations, where at least some of said base stations conduct control communications over analog control channels and at least some of said base stations conduct control communications over digital control channels, each of said mobile stations comprising:

means for scanning a set of digital control channels to detect if any such digital control channel is being transmitted from an associated base station;

means for determining if a recognizable overhead message is received by said mobile station on said digital control channel;

means for scanning a set of digital paging channels if said overhead message is received; and

means for scanning a set of primary analog control channels if said recognizable overhead message is not received;

wherein said digital control and paging channels are assigned time slots on the same frequency, and wherein said frequency includes a plurality of frames, each frame including three time slots with a first time slot being reserved for said digital control channel and a second and third time slot being reserved for said digital paging channels organized in multiple frames.

14. The system according to claim 13, wherein said multiple frame includes sixty-four frames and said synchronization signal indicates the beginning of each multiple frame.

15. The system according to claim 13, wherein said second and third time slots contain paging information for a plurality of different mobile stations.

16. The system according to claim 13, wherein paging information is distributed over said second and third time slots in each frame of said multiple frame and excess paging information that can not be communicated in a particular multiple frame is queued at said base station.

17. A mobile station for use in a cellular radio telephone communication system having analog or digital traffic channels and analog and digital control channels, comprising:

means for transmitting and receiving speech and data information over said analog and digital traffic channels;

means for receiving and decoding control information transmitted over an analog control channel in an analog format; and

means for receiving and decoding control information that is transmitted over a digital control channel in a digital format;

a mode selection switch for switching a mobile station between an analog mode and a digital mode, said switch being initially set to its digital mode for receiving digital control communications over said digital control channel from a base station;

means for scanning a set of digital control channels, received from said digital control communications when said mobile station is switched to a digital mode;

first overhead message receiving means for determining if one of said digital control channels is available;

means for conducting control communications with one of said base stations over a digital control channel associated with this base station if said one of the digital control channels is available;

means for scanning a set of analog control channels if none of said digital control channels is available;

second overhead message receiving means for determining if one of said analog control channels is available; and

means for conducting control communications with one of said base stations over an analog control channel associated with this base station if said one of the analog control channels is available.

18. The mobile station of claim 17, further including means for selectively activating said receiving means during predetermined timeslots in a multiframe and deactivating said receiving means during other times to thereby reduce power consumption.

19. The mobile station of claim 18, wherein said mobile station has a binary identification number and said timeslots in a multiframe are determined by a predetermined number of bits in said identification number.

20. The mobile station of claim 17, wherein said speech information is transmitted and received over said analog traffic channels in an analog format.

21. The mobile station of claim 17, further comprising:

means for transmitting control information over said analog control channel.

22. The mobile station according to claim 21, further comprising:

means for transmitting control information over said digital control channel.

23. A cellular radio telephone communications system for communicating over analog or digital traffic channels, comprising:

a mobile switching center;

plural base stations connected to said mobile switching center, for receiving and transmitting speech information and control information; and

plural mobile radio telephone stations, including at least one multi-mode mobile station including;

means for receiving speech and data information from a first base station over the analog and digital traffic channels;

means for transmitting speech and data information to said first base station over the analog and digital traffic channels;

means for receiving and decoding control information in an analog format from said first base station over an analog control channel; and

means for receiving and decoding control information in a digital format from said first base station over a digital control channel;

a mode selection switch for switching the mobile station between an analog mode and a digital mode, said switch being initially set to its digital mode for receiving digital control communications over said digital control channel from one of the base stations;

means for scanning a set of digital control channels, received from said digital control communications when said mobile station is switched to a digital mode;

first overhead message receiving means for determining if one of said digital control channels is available;

means for conducting control communications with one of said base stations over a digital control channel associated with this base station if said one of the digital control channels is available;

means for scanning a set of analog control channels if none of said digital control channels is available;

second overhead message receiving means for determining if one of said analog control channels is available; and

means for conducting control communications with one of said base stations over an analog control channel associated with this base station if said one of the analog control channels is available.

24. The system according to claim 23, wherein each multi-mode mobile station further includes:

means for transmitting control information over said analog control channel.

25. The system according to claim 24, wherein at least some of said multi-mode mobile stations also include:

means for transmitting control information over said digital control channel.

26. The system according to claim 23, each multi-mode mobile station further comprising:

means for periodically scanning said digital control channel;

means for deactivating power to said mobile in the absence of paging information for said mobile station; and

means for reactivating said scanning means after a preset time period.