Method of directing a call to a mobile telephone in a dual mode cellular-satellite communications network

• US 6,418,319 B1
• Filed: 03/16/2000
• Issued: 07/09/2002
• Est. Priority Date: 01/11/1994
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson), Telefonaktiebolaget LM Ericsson
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Dent, Paul W.
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US09/526,673
• Time in Patent Office: 845 Days
• Field of Search: 455/456
• US Class Current: 455/456.3
• CPC Class Codes: H04B 7/18545 Arrangements for managing station mobility, i.e. for station registration or localisation
• CPC Class Codes: H04B 7/1855 using a telephonic control signal, e.g. propagation delay variation, Doppler frequency variation, power variation, beam identification
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 68/02 Arrangements for increasing efficiency of notification or paging channel
• CPC Class Codes: H04W 68/12 Inter-network notification
• CPC Class Codes: H04W 8/10 between location register and external networks
• 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 method for determining the position of a mobile radio telephone in a satellite communication system includes a mobile radio telephone scanning a plurality of paging channels and measuring the signal strength of the paging channels. The mobile radio telephone then selects the paging channel with the strongest signal strength and decodes the information broadcasted on the selected channel. The information contained in the paging channel can include frequencies or timeslots of paging channels in surrounding spot beams. The mobile station then measures the signal strength of paging channels in surrounding spot beams and quantizes the measurements to determine a coarse position of the mobile radio telephone.

Claims

1. A method of directing a call to a mobile telephone in a dual-mode cellular-satellite communications network, comprising the steps of:

transmitting an alert signal to said mobile telephone using base stations of said cellular network if the mobile telephone is currently registered as active in a cellular network, wherein said alert signal transmitted from said cellular network comprises a first attempt at first power levels and a second attempt at a higher power level;

receiving said alert signal at said mobile telephone;

transmitting a response to said cellular network as an acknowledgment;

upon non-receipt of said acknowledgment by the cellular network within a defined period of time, transmitting a last known location of the mobile telephone from said cellular network to a satellite earth station;

upon receipt of said last known location of the mobile telephone at said satellite earth station, using said last known location to determine a satellite antenna beam most likely to be received by said mobile telephone and transmitting an alert signal to said mobile telephone via a satellite using said antenna beam;

receiving the alert signal transmitted via the satellite at the mobile telephone; and

transmitting a response from the mobile telephone via the satellite acknowledging the alert signal.

2. A method of directing a call according to claim 1, further comprising the steps of:

receiving said acknowledgment transmitted via said satellite at the satellite earth station;

allocating a traffic channel for communicating with said mobile telephone and completing a two-way connection between said mobile telephone and a calling party.

3. A method of directing a call according to claim 2, further comprising the step of:

transmitting an indication from said satellite earth station to a cellular network that the mobile telephone is reachable via said satellite earth station.

4. A method of directing a call according to claim 1, wherein said alert signal transmitted from the cellular network comprises a first attempt at a first power level and a second attempt at a higher power level in a likely paging area and simultaneously at said first power level in a wider paging area.

5. A method of directing a call according to claim 1, wherein said alert signal transmitted from said cellular network comprises a first attempt transmitted in a last known paging area and a second attempt transmitted in a wider paging area.

6. A method of directing a call according to claim 1, wherein said alert signal transmitted using said satellite antenna beam comprises a first attempt at first power levels and a second attempt at a higher power level.

7. A method of directing a call to a mobile telephone in a dual-mode cellular-satellite communications network, comprising the steps of:

transmitting an alert signal to said mobile telephone using base stations of said cellular network if the mobile telephone is currently registered as active in a cellular network;

receiving said alert signal at said mobile telephone;

transmitting a response from said mobile telephone via said satellite acknowledging said alert signal;

upon non-receipt of said acknowledgment by the cellular network within a defined period of time, transmitting a last known location of the mobile telephone from said cellular network to a satellite earth station;

upon non-receipt at a satellite earth station of said acknowledgment from said mobile telephone, transmitting a further attempt using said satellite in an extended satellite paging area, wherein said extended satellite paging area comprises several beams;

upon receipt of said last known location of the mobile telephone at said satellite earth station, using said last known location to determine a satellite antenna beam most likely to be received by said mobile telephone and transmitting an alert signal to said mobile telephone via a satellite using said antenna beam;

receiving said acknowledgment transmitted via said satellite at the satellite earth station; and

allocating a traffic channel for communicating with said mobile telephone and completing a two-way connection between said mobile telephone and a calling party.

8. A method of directing a call according to claim 7, further comprising the step of:

transmitting an indication from said satellite earth station to a cellular network that the mobile telephone is reachable via said satellite earth station.

9. A method of directing a call according to claim 7, wherein said alert signal transmitted from the cellular network comprises a first attempt at a first power level and a second attempt at a higher power level in a likely paging area and simultaneously at said first power level in a wider paging area.

10. A method of directing a call according to claim 7, wherein said alert signal transmitted from said cellular network comprises a first attempt transmitted in a last known paging area and a second attempt transmitted in a wider paging area.

11. A method of directing a call according to claim 7, wherein said alert signal transmitted using said satellite antenna beam comprises a first attempt at first power levels and a second attempt at a higher power level.

12. A method of directing a call to a mobile telephone in a dual-mode cellular-satellite communications network, comprising the steps of:

transmitting an alert signal to said mobile telephone using base stations of said cellular network if the mobile telephone is currently registered as active in a cellular network;

receiving said alert signal at said mobile telephone;

transmitting a response from said mobile telephone via said satellite acknowledging said alert signal;

upon non-receipt of said acknowledgment by the cellular network within a defined period of time, transmitting a last known location of the mobile telephone from said cellular network to a satellite earth station;

upon non-receipt at a satellite earth station of said acknowledgment from said mobile telephone, transmitting a further attempt using said satellite in an extended satellite paging area, wherein said extended satellite paging area comprises a beam of wider bandwidth;

upon receipt of said last known location of the mobile telephone at said satellite earth station, using said last known location to determine a satellite antenna beam most likely to be received by said mobile telephone and transmitting an alert signal to said mobile telephone via a satellite using said antenna beam; and

transmitting said further attempt in said first satellite paging area at an increased power level.

13. A method of directing a call according to claim 12, further comprising the step of:

transmitting said further attempt in the first satellite paging area using increased error correcting coding.

14. A method of directing a call according to claim 12, further comprising the steps of:

receiving said acknowledgment transmitted via said satellite at the satellite earth station;

allocating a traffic channel for communicating with said mobile telephone and completing a two-way connection between said mobile telephone and a calling party.

15. A method of directing a call according to claim 14, further comprising the step of:

transmitting an indication from said satellite earth station to a cellular network that the mobile telephone is reachable via said satellite earth station.

16. A method of directing a call according to claim 13, wherein said alert signal transmitted from the cellular network comprises a first attempt at a first power level and a second attempt at a higher power level in a likely paging area and simultaneously at said first power level in a wider paging area.

17. A method of directing a call according to claim 13, wherein said alert signal transmitted from said cellular network comprises a first attempt transmitted in a last known paging area and a second attempt transmitted in a wider paging area.

18. A method of directing a call according to claim 13, wherein said alert signal transmitted using said satellite antenna beam comprises a first attempt at first power levels and a second attempt at a higher power level.