Radiotelephone communication systems and methods that map an access request into a predetermined random access channel slot to identify a nearest gateway to a radiotelephone

• US 6,014,562 A
• Filed: 05/19/1998
• Issued: 01/11/2000
• Est. Priority Date: 05/19/1998
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Weiss, Richard Edward
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Tran, Congvan
• Application Number:
  US09/081,129
• Time in Patent Office: 602 Days
• Field of Search: 455/427, 455/510, 455/450, 455/428, 455/403, 455/422, 455/426, 455/500, 370/335, 370/337, 370/346, 370/329, 370/348, 370/438
• US Class Current: 455/427
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185
• 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

An access request by a radiotelephone for one of a plurality of radiotelephone traffic channels is mapped into a predetermined one of a repeating series of Random Access CHannel (RACH) slots, based upon information concerning the access request by the radiotelephone. Accordingly, the RACH slot in which the access request is placed, conveys additional information about the access request. This additional information can be conveyed and decoded without the need to modify the RACH protocol or to extend the length of the RACH slots.

Claims

1. A radiotelephone communication system comprising:

a plurality of radiotelephones;

at least one base station comprising a plurality of gateways;

a plurality of radiotelephone traffic channels that are used by the radiotelephones for radiotelephone communication via the at least one base station;

a Random Access CHannel (RACH) including repeating frames of RACH slots that are used by the radiotelephones to request access to one of the radiotelephone traffic channels by placing an access request message in a RACH slot; and

means for mapping an access request by a radiotelephone into a predetermined one of the RACH slots based upon a nearest gateway to the radiotelephone such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

2. A radiotelephone communication system according to claim 1 wherein the radiotelephone communication system is a satellite radiotelephone communication system including at least one satellite.

3. A radiotelephone communication system according to claim 1 wherein the plurality of gateways is a first and a second gateway, and wherein the repeating frames of RACH slots are repeating frames of odd and even RACH slots, the means for mapping comprising:

means for mapping an access request by a radiotelephone into an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone, and for mapping the access request by the radiotelephone into an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

4. A radiotelephone communication system according to claim 1 further comprising:

means for generating a random number to indicate a selected frame of RACH slots to be sued by the radiotelephone to request access to one of the radiotelephone traffic channels;

the means for mapping comprising means for mapping an access request by the radiotelephone into a predetermined one of the RACH slots in the selected frame of RACH slots indicated by the random number, based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

5. A radiotelephone communication system comprising:

a plurality of radiotelephones;

at least one base station comprising a plurality of gateways;

a plurality of radiotelephone traffic channels that are used by the radiotelephones for radiotelephone communication via the at least one base station;

a Random Access CHannel (RACH) including repeating frames of RACH slots that are used by the radiotelephones to request access to one of the radiotelephone traffic channels by placing an access request message in a RACH slot; and

a circuit that maps an access request by a radiotelephone into a predetermined one of the RACH slots based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

6. A radiotelephone communication system according to claim 5 wherein the radiotelephone communication system is a satellite radiotelephone communication system including at least one satellite.

7. A radiotelephone communication system according to claim 5 wherein the plurality of gateways is a first and a second gateway, and wherein the repeating frames of RACH slots are repeating frames of odd and even RACH slots, the circuit comprising:

a circuit that maps an access request by a radiotelephone into an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone, and that maps the access request by the radiotelephone into an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

8. A radiotelephone communication system according to claim 5 further comprising:

a random number generator that indicates a selected frame of RACH slots to be used by the radiotelephone to request access to one of the radiotelephone traffic channels;

the circuit comprising a circuit that maps an access request by the radiotelephone into a predetermined one of the RACH slots in the selected frame of RACH slots indicated by the random number, based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

9. An access requesting method for a radiotelephone communication system comprising a plurality of radiotelephones, at least one base station comprising a plurality of gateways, a plurality of radiotelephone traffic channels that are used by the radiotelephones for radiotelephone communication via the at least one base station, and a Random Access CHannel (RACH) including repeating frames of RACH slots that are used by the radiotelephones to request access to one of the radiotelephone traffic channels by placing an access request message in a RACH slot, the access requesting method comprising the step of:

mapping an access request by a radiotelephone into a predetermined one of the RACH slots based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

10. A method according to claim 9 wherein the radiotelephone communication system is a satellite radiotelephone communication system including at least one satellite.

11. A method according to claim 9 wherein the plurality of gateways is a first and a second gateway, and wherein the repeating frames of RACH slots are repeating frames of odd and even RACH slots, the mapping step comprising the steps of:

mapping an access request by a radiotelephone into an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone; and

mapping the access request by the radiotelephone into an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

12. A method according to claim 9 wherein the mapping step is preceded by the step of:

generating a random number to indicate a selected frame of RACH slots to be used by the radiotelephone to request access to one of the radiotelephone traffic channels;

the mapping step comprising the step of mapping an access request by the radiotelephone into a predetermined one of the RACH slots in the selected frame of RACH slots indicated by the random number, based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

13. A radiotelephone comprising:

means for communicating with at least one base station of a radiotelephone communication system comprising a plurality of gateways, using one of a plurality of radiotelephone traffic channels; and

means for mapping an access request by the radiotelephone for one of the radiotelephone traffic channels into a predetermined Random Access CHannel (RACH) slot based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

14. A radiotelephone according to claim 13 wherein the radiotelephone communication system is a satellite radiotelephone communication system including at least one satellite.

15. A radiotelephone according to claim 13 wherein the plurality of gateways is a first and a second gateway, and wherein the RACH slots are odd and even RACH slots, the means for mapping comprising:

means for mapping an access request by a radiotelephone into an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone, and for mapping the access request by the radiotelephone into an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

16. A radiotelephone according to claim 13 wherein the RACH slots are arranged in repeating frames of RACH slots, the radiotelephone further comprising:

means for generating a random number to indicate a selected frame of RACH slots to be used by the radiotelephone to request access to one of the radiotelephone traffic channels;

the means for mapping comprising means for mapping an access request by the radiotelephone into a predetermined RACH slot in the selected frame of RACH slots indicated by the random number, based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

17. A radiotelephone comprising:

a transceiver that communicates with at least one base station of a radiotelephone communication system comprising a plurality of gateways, using one of a plurality of radiotelephone traffic channels; and

a circuit that maps an access request by the radiotelephone for one of the radiotelephone traffic channels into a predetermined Random Access CHannel (RACH) slot based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

18. A radiotelephone according to claim 17 wherein the radiotelephone communication system is a satellite radiotelephone communication system including at least one satellite.

19. A radiotelephone according to claim 17 wherein the plurality of gateways is a first and a second gateway, and wherein the RACH slots are odd and even RACH slots, the circuit comprising:

a circuit that maps an access request by a radiotelephone into an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone, and that maps the access request by the radiotelephone into an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

20. A radiotelephone according to claim 17 wherein the RACH slots are arranged in repeating frames of RACH slots, the radiotelephone further comprising:

a random number generator that indicates a selected frame of RACH slots to be used by the radiotelephone to request access to one of the radiotelephone traffic channels;

the circuit comprising a circuit that maps an access request by the radiotelephone into a predetermined RACH slot in the selected frame of RACH slots indicated by the random number, based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

21. A method of operating a radiotelephone comprising the step of:

mapping an access request by the radiotelephone for one of a plurality of radiotelephone traffic channels of a radiotelephone communication system comprising a plurality of gateways into a predetermined Random Access CHannel (RACH) slot based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

22. A method according to claim 21 wherein the radiotelephone communication system is a satellite radiotelephone communication system including at least one satellite.

23. A method according to claim 21, wherein the plurality of gateways is a first and a second gateway, and wherein the RACH slots are odd and even RACH slots, the mapping step comprising the steps of:

mapping an access request by a radiotelephone into an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone; and

mapping the access request by the radiotelephone into an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

24. A method according to claim 21 wherein the RACH slots are arranged in repeating frames of RACH slots and wherein the mapping step is preceded by the step of:

generating a random number to indicate a selected frame of RACH slots to be used by the radiotelephone to request access to one of the radiotelephone traffic channels;

the mapping step comprising the step of mapping an access request by the radiotelephone into a predetermined RACH slot in the selected frame of RACH slots indicated by the random number, based upon a nearest gateway to the radiotelephone, such that the RACH slot in which an access request is placed identifies the nearest gateway to the radiotelephone.

25. A radiotelephone communication system base station that communicates with a plurality of radiotelephones, the base station comprising:

a plurality of gateways;

means for receiving a plurality of radiotelephone traffic channels that are used by the radiotelphone for radiotelephone communication with the base station;

means for receiving a Random Access CHannel (RACH) including repeating frames of RACH slots that are used by the radiotelephones to request access to one of the radiotelephone traffic channels by placing an access request message in a RACH slot; and

means for decoding an identification of a nearest gateway to a radiotelephone based upon identification of the RACH slot in which the access request message is received, such that the RACH slot in which an access request is received identifies the nearest gateway to the radiotelephone.

26. A base station according to claim 25 wherein the base station is a satellite radiotelephone communication system base station.

27. A base station according to claim 25 wherein the plurality of gateways is a first and a second gateway, and wherein the repeating frames of RACH slots are repeating frames of odd and even RACH slots, the means for decoding comprising:

means for decoding an access request by a radiotelephone in an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone, and for decoding the access request by the radiotelephone is an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

28. A radiotelephone communication system base station that communicates with a plurality of radiotelephones, using a plurality of radiotelephone traffic channels and a Random Access CHannel (RACH) including repeating frames of RACH slots that are used by the radiotelephones to request access to one of the radiotelephone traffic channels by placing an access request message in a RACH slot, the base station comprising:

a plurality of gateways; and

a circuit that decodes an identification of a nearest gateway to a radiotelephone based upon identification of the RACH slot in which the access message is received, such that the RACH slot in which an access request is received identifies the nearest gateway to the radiotelephone.

29. A base station according to claim 28 wherein the base station is a satellite radiotelephone communication base station.

30. A base station according to claim 28 wherein the plurality of gateways is a first and a second gateway, and wherein the repeating frames of RACH slots are repeating frames of odd and even RACH slots, the circuit comprising:

a circuit that decodes an access request by a radiotelephone in an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone, and that decodes the access request by the radiotelephone in an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.

31. A method of operating a radiotelephone communication system base station comprising a plurality of gateways, that communicates with a plurality of radiotelephones using a plurality of radiotelephone traffic channels and a Random Access CHannel (RACH) including repeating frames of RACH slots that are used by the radiotelephone to request access to one of the radiotelephone traffic channels by placing an access request message in a RACH slot, the method comprising the step of:

decoding an identification of a nearest gateway to a radiotelephone based upon identification of the RACH slot in which the access request message is received, such that the RACH slot in which an access request is received identifies the nearest gateway to the radiotelephone.

32. A method according to claim 31 wherein the base station is a satellite radiotelephone communication system base station.

33. A method according to claim 31 wherein the plurality of gateways is a first and a second gateway, and wherein the repeating frames of RACH slots are repeating frames of odd and even RACH slots, the decoding step comprising the steps of:

decoding an access request by a radiotelephone in an odd RACH slot to indicate that the first gateway is nearest to the radiotelephone; and

decoding the access request by the radiotelephone in an even RACH slot to indicate that the second gateway is nearest to the radiotelephone.