Cellular telecommunications network having seamless interoperability between exchanges while providing voice, asynchronous data and facsimile services in multiple frequency hyperbands

• US 5,857,153 A
• Filed: 08/06/1996
• Issued: 01/05/1999
• Est. Priority Date: 10/13/1995
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Lupien, Francis
• Primary Examiner(s): Cumming, William
• Assistant Examiner(s): Bethea, Jr., Thomas
• Application Number:
  US08/692,743
• Time in Patent Office: 882 Days
• Field of Search: 455/422, 455/432, 455/466, 455/436, 455/426, 455/509, 455/560, 455/433
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network
• CPC Class Codes: H04W 68/12 Inter-network notification
• 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 system and method of providing seamless interoperability for a mobile station roaming between cellular telecommunication systems operating in multiple hyperbands such as the 1900-MHz PCS hyperband and the 800-MHz cellular telephone hyperband, utilizing United States cellular standards. An enhanced inter-exchange communications protocol based on IS-41 is utilized to communicate information required for seamless interoperability between mobile switching centers (MSCs). The enhanced inter-exchange communications protocol comprises a plurality of signaling messages and a plurality of modified message parameters within the signaling messages. The modified message parameters are modified to include information elements required for seamless interoperability between the multi-hyperband capable exchanges and are added as optional (overriding) parameters to the signaling messages.

Claims

1. A cellular telecommunications network providing seamless call delivery inter-change handoffs, inter-exchange cell reselections inter-hyperband handoffs, and inter-hyperband cell reselections for voice calls, asynchronous data calls, and facsimile calls for a mobile station roaming between multi-hyperband capable exchanges, said cellular telecommunications network comprising:

a plurality of mobile switching centers (MSCs) having means for operating in a plurality of frequency hyperbands;

a plurality of base stations connected to each of said plurality of MSCs, said base stations having transmission and reception equipment operating in the plurality of frequency hyperbands;

an inter-exchange communications protocol for communicating information required for seamless interoperability between said plurality of MSCs and said plurality of frequency hyperbands, said inter-exchange communications protocol comprising;

a plurality of signaling messages in an industry standard message format, and

a plurality of modified message parameters within sad signaling messages, said modified message parameters including unmodified information elements, modified information elements, and new information elements which provide seamless call delivery, inter-exchange handoffs, inter-exchange cell reselections, inter-hyperband handoffs, and inter-hyperband cell reselections for voice calls, asynchronous data calls, and facsimile calls between said multi-hyperband capable exchanges and said plurality of frequency hyperbands.

2. The cellular telecommunications network of claim 1 wherein said industry standard message format is the IS-41 message format.

3. The cellular telecommunications network of claim 2 wherein said transmission and reception equipment operates in an 800-MHz cellular telephone hyperband and a 1900-MHz personal communication system (PCS) hyperband.

4. The cellular telecommunications network of claim 2 wherein said modified message parameters include new optional parameters that override mandatory parameters in said signaling messages, said optional parameters including said information elements which provide seamless call delivery, handoffs, and reselections between said multi-hyperband capable exchanges and said plurality of frequency hyperbands.

5. The cellular telecommunications network of claim 4 wherein said modified message parameters include new optional parameters that replace existing optional parameters in said signaling messages, said new optional parameters including said information elements which provide seamless call delivery, handoffs, and reselections between said multi-hyperband capable exchanges and said plurality of frequency hyperbands.

6. The cellular telecommunications network of claim 5 wherein said unmodified IS-41 information elements include:

an information element that commands initial mobile station power level;

an information element that identifies particular cells; and

an information element that identifies digital traffic channel numbers.

7. The cellular telecommunications network of claim 6 wherein said modified IS-41 information elements include an information element that indicates a time slot and rate for an assigned traffic channel.

8. The cellular telecommunications network of claim 7 wherein said new information elements include:

an information element that provides frequency band information for specifying a hyperband for a channel;

an information element that identifies digital traffic channel bandwidth requirements;

an information element that identifies a voice mode for requested voice calls;

an information element that identifies requested services;

an information element that indicates which frequency bands and hyperbands are supported by a mobile station;

an information element that indicates a mobile station'"'"'s protocol version;

an information element that indicates which voice coders are supported by a mobile subscriber; and

an information element that indicates an intersystem link protocol for asynchronous data calls and facsimile calls between exchanges.

9. The cellular telecommunications network of claim 8 wherein said optional parameters include Hyperband Digital Channel Data (HDCD), Hyperband Call Mode (HCM), Terminal Characteristics (TCH), and Subscriber Characteristics (SCH).

10. The cellular telecommunications network of claim 9 wherein a first subset of said plurality of signaling messages supports call delivery for voice, asynchronous data, and facsimile services to said mobile station.

11. The cellular telecommunications network of claim 10 wherein said first subset of said plurality of signaling messages includes a Registration Notification Return Result message, a Qualification Directive Invoke message, a Qualification Request Return Result message, a Location Request Invoke message, a Location Request Return Result message, a Routing Request Invoke message, a Routing Request Return Result message, and an Intersystem Page Invoke message.

12. The cellular telecommunications network of claim 10 wherein a second subset of said plurality of signaling messages supports inter-hyperband and inter-exchange handoff for voice, asynchronous data, and facsimile services to said mobile station.

13. The cellular telecommunications network of claim 12 wherein said second subset of said plurality of signaling messages includes a Facilities Directive Invoke message, a Handoff Back Invoke message, a Handoff to Third Invoke message, a Facilities Directive Return Result message, a Handoff Back Return Result message, a Handoff to Third Return Result message, and a Handoff Measurement Request Invoke message.

14. A method of providing seamless call delivery inter-exchange handoffs, inter-exchange cell reselections inter-hyperband handoffs, and inter-hyperband cell reselections for voice calls, asynchronous data calls, and facsimile calls for a mobile station roaming between a plurality of multi-hyperband capable exchanges in a cellular telecommunications network, said method comprising the steps of:

connecting a plurality of multi-hyperband capable mobile switching centers (MSCs) to a plurality of base stations having transmission and reception equipment operating in a plurality of frequency hyperbands; and

communicating information between said plurality of MSCs with an inter-exchange communications protocol having a plurality of signaling messages comprising a plurality of message parameters, said communicating step further comprising the steps of;

formatting said plurality of signaling messages in an industry standard message format, and

modifying said plurality of signalling messages and said plurality of message parameters by adding modified information elements and new information elements which, together with unmodified information elements, provide seamless call delivery, inter-exchange handoffs, inter-exchange cell reselections, inter-hyperband handoffs, and inter-hyperband cell reselections for voice calls, asynchronous data calls, and fascimile calls between said multi-hyperband capable exchanges and said plurality of frequency hyberbands.

15. The method of claim 14 wherein said step of formatting said plurality of signaling messages in an industry standard message format includes formatting said messages in the IS-41 message format.

16. The method of claim 15 wherein said step of connecting to each MSC, a plurality of base stations includes connecting base stations having transmission and reception equipment that operates in an 800-MHz cellular telephone hyperband and a 1900-MHz personal communication system (PCS) hyperband.

17. The method of claim 15 wherein said step of modifying said plurality of signaling messages and said plurality of message parameters includes adding new optional parameters that override mandatory parameters in said signaling messages, said optional parameters including said information elements which provide seamless call delivery handoffs, and reselections between said multi-hyperband capable exchanges and said plurality of frequency hyperbands.

18. The method of claim 17 wherein said step of adding new optional parameters that override mandatory parameters in said signaling messages includes adding optional parameters with unmodified IS-41 information elements, modified IS-41 information elements, and new information elements.

19. The method of claim 18 wherein said step of modifying said plurality of signalling messages and said plurality of message parameters includes adding new optional parameters that replace existing optional parameters in said signaling messages, said new optional parameters including said information elements which provide seamless call delivery, handoffs, and reselections between said multi-hyperband capable exchanges and said plurality of frequency hyperbands.