EP0522773A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Mobile-telephone system call processing arrangement
Assignee: AT&T Inc
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Filing: 1992-06-30
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Granted: —
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Expires: 2012-06-30
Abstract
Abstract A CDMA cellular radio-telephone system comprises a packet-switched communications network (202, 207, 201) that interconnects cells (base stations; 202) with each other and with the public telephone network (100). A unique combination of a static addressing plan that uses a different LAPD DLCI for each unidirectional virtual call path, direct cell (202)-to-cell and cell-to-call-processing unit control information exchanges, and packet-switching techniques that permit call traffic and control communications to share call paths and permit different call paths to share physical resources, is applied to call processing. This enables soft handoffs to be handled in a manner transparent to the parties to the call and without significant involvement of system control elements (134 and 261) whose involvement would adversely impact the system's call-handling capacity. It also enables soft handoffs to occur without change of the call processing unit that is handling the call, so that a single call processing unit continues to handle the call from start to finish through even multiple soft handoffs.
Inventors
- 👤 Brian David Bollinger
- 👤 Talmage P. Bursh Jr
- 👤 Kelvin Ki-Yui Ho
- 👤 Alan Stuart Mulberg
- 👤 Lajeana Nicole Roberts
- 👤 Kenneth Frank Smolik
- 👤 Douglas Albert Spencer
- 👤 Kenneth Wayne Strom
- 👤 John Stewart Thompson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 22:54
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/16; H04W36/18; H04W8/00; H04W8/26
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
423 words
A method of handling a call of a mobile wireless-call user terminal that is moving from a vicinity of a first service node to a vicinity of a second service node in a wireless-access telecommunications system that includes the mobile wireless-call user terminal, a plurality of service nodes each for providing wireless-call services to wireless-call user terminals in its vicinity, and at least one interface node connected to the service nodes and having a plurality of call processing units each for interfacing a wireless call that extends between a user terminal and a service node to a telecommunications facility, the method comprising the steps of: communicating call traffic of the call between the mobile user terminal and the first service node, and between one of the call processing units and a telecommunications facility; communicating the call traffic of the call between the first service node and the one call processing unit across a packet-switched call path set up for the call on a communication channel between the first service node and the one call processing unit, using different fixed addresses for different endpoints of the call path to route the call traffic across the channel; in response to detecting that the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node, sending notification thereof from the first service node to the second service node; in response to receiving the notification at the second service node, setting up a packet-switched call path for the call on a communication channel between the second service node and the one call processing unit by communicating across the communication channel between the second service node and the one call processing unit; communicating duplicate call traffic of the call between the mobile user terminal and the first and the second service nodes; communicating the duplicate call traffic of the call between the first and the second service nodes and the one call processing unit across the packet-switched call paths set up for the call on the communication channels between the first and the second service nodes and the one call processing unit, using different fixed addresses for different endpoints of every call path to route the duplicate call traffic across the channels; and communicating a single copy of the duplicate call traffic of the call between the one call processing unit and the telecommunications facility by duplicating the call traffic outgoing to the service nodes and discarding a duplicate of the call traffic incoming from the service nodes.
Claim 2
Dependent Claim
43 words
The method of claim 1 wherein each step of communicating call traffic of the call between a service node and a call processing unit comprises the step of: frame-relaying packets containing the call traffic between the service node and the call processing unit.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein: each address of a call-path endpoint located at a service node identifies a wireless channel of the service node which corresponds to the call.
Claim 4
Dependent Claim
30 words
The method of claim 3 wherein: each address of a call-path endpoint located at the one call processing unit identifies a different logical port of the one call processing unit.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein: each different address of a call-path endpoint comprises a different DLCI of LAPD packets carrying the call traffic of the call.
Claim 6
Dependent Claim
34 words
The method of claim 1 in a wireless-access telecommunications system that further includes a controller for connecting call processing units to calls, wherein: the recited steps all occur without involvement therein of the controller.
Claim 7
Dependent Claim
39 words
The method of claim 1 in a wireless-access telecominunications system that further includes a system controller for coordinating operations of the service nodes and the interface node, wherein: the recited steps all occur without involvement therein of the controller.
Claim 8
Dependent Claim
51 words
The method of claim 1 in a wireless-access telecommunications system that further includes an interface node controller for connecting call processing units to calls and a supervisory controller for coordinating operations of the service nodes and the interface node, wherein: the recited steps all occur without involvement therein of the controllers.
Claim 9
Dependent Claim
198 words
The method of claim 8 wherein the recited steps are preceded by the further steps of: detecting an origination of the call; in response to the detection of the origination, notifying thereof the supervisory controller; in response to the notification, sending a first message from the supervisory controller to the first service node to establish a call path for the call between the first service node and the one call processing unit; in response to the notification, sending a second message from the supervisory controller to the interface node controller to establish a call connection for the call between the one call processing unit and the telecommunications facility; in response to receiving the second message at the interface node controller, establishing a call connection for the call between the one call processing unit and the telecommunications facility by action of the interface node controller, and in response to receiving the first message at the first service node, setting up the packet-switched call path for the call on the communication channel between the first service node and the one call processing unit by communicating across the communication channel between the first service node and the one call processing unit.
Claim 10
Independent Claim
221 words
The method of claims 1 further comprising the steps of: in response to detecting that the mobile user terminal is moving from a vicinity of both the first and the second service nodes to the vicinity of only an individual one of the first and the second service nodes, sending notification thereof from a detecting one of the first and the second service nodes to another one of the first and the second service nodes to indicate transfer of responsibility for the call to solely the individual one of the first and the second service nodes; in response to the detecting, ceasing to communicate call traffic of the call from the other than the individual one of the first and the second service nodes; in response to the detecting, communicating a notification thereof from the other than the individual one of the first and the second service nodes to the one call processing unit across the communication channel between the other than the individual one of the first and the second service nodes and the one call processing unit; and in response to receiving the notification at the one call processing unit, ceasing to communicate call traffic of the call from the one call processing unit to the other than the individual one of the first and the second service nodes.
Claim 11
Independent Claim
632 words
A method of handling a call of a mobile wireless-call user terminal that is moving from a vicinity of a first service node to a vicinity of a second service node in a wireless-access telecommunications system that includes the mobile wireless-call user terminal, a plurality of service nodes each for providing wireless-call services to wireless-call user terminals in its vicinity, and at least one interface node connected to the service nodes and having a plurality of call processing units each for interfacing a wireless call that extends between a user terminal and a service node to a telecommunications facility, the method comprising the steps of: in response to receiving incoming call traffic of the call from the mobile user terminal at the first service node, sending first packets containing the received incoming call traffic and each having a first address which identifies the call's corresponding one of the call processing units, from the first service node to the interface node; in response to receiving the first packets at the one call processing unit, sending the incoming call traffic contained in the first packets from the one call processing unit to a telecommunications facility; in response to receiving outgoing call traffic of the call from the telecommunications facility at the one call processing unit, sending second packets containing the received outgoing call traffic and each having a second address different from the first address and which identifies the first service node, from the one call processing unit to the first service node; in response to receiving the second packets at the first service node, sending the outgoing call traffic contained in the second packets from the first service node to the mobile user terminal; detecting that the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node; in response to the detecting, sending a message specifying a third address different from the first address and which also identifies the one call processing unit, from the first service node to the second service node; in response to receiving the message at the second service node, sending a third packet both (a) specifying a fourth address different from the second and the third addresses and which identifies the second service node and (b) having the third address, from the second service node to the interface node; in response to receiving incoming call traffic of the call from the mobile user terminal at the second service node subsequently to receiving the message, sending fourth packets containing the received incoming call traffic and each having the third address, from the second service node to the interface node; in response to receiving the third packet at the one call processing unit, storing the fourth address for use in the call by the one call processing unit; in response to receiving outgoing call traffic of the call from the telecommunications facility subsequently to receiving the third packet, sending the second packets from the one call processing unit to the first service node and sending fifth packets containing same received outgoing call traffic as the second packets and each having the fourth address, from the one call processing unit to the second service node; in response to receiving the fifth packets at the second service node, sending the outgoing call traffic contained in the fifth packets from the second service node to the mobile user terminal; and in response to receiving the first packets and the fourth packets both containing same received incoming call traffic at the one call processing unit subsequently to receiving the third packet, selecting the incoming call traffic contained by one of the received first and fourth packets that contain the same traffic, and sending only the selected incoming call traffic to the telecommunications facility.
Claim 12
Dependent Claim
584 words
In a wireless-access telecommunications system that includes at least one mobile wireless-call user terminal, a plurality of service nodes each for providing wireless-call services to wireless-call user terminals in its vicinity, and at least one interface node connected to the service nodes and having a plurality of call processing units each for interfacing a wireless call that extends between a user terminal and a service node to a telecommunications facility, the improvement comprising: first means for communicating call traffic of the call between a mobile user terminal that is in the vicinity of the first service node and the first service node; second means cooperative with the first means for communicating the call traffic of the call between the first service node and the call's associated one of the call processing units across a packet-switched call path set up for the call on a communication channel between the first service node and the one of the call processing units, by using different fixed addresses for different endpoints of the call path to route the call traffic across the channel; third means cooperative with the second means for communicating the call traffic of the call between the one call processing unit and a telecommunications facility; fourth means in the first service node responsive to detecting that the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node, for sending notification thereof to the second service node; fifth means in the second service node responsive to receiving the notification, for setting up a packet-switched call path for the call on a communication channel between the second service node and the one call processing unit by communicating across the communication channel with the one call processing unit; sixth means for communicating the call traffic of the call between the mobile user terminal moving into the vicinity of the second service node and the second service node, so that duplicate copies of the call traffic are communicated between the mobile user terminal when it is moving from the vicinity of the first service node to the vicinity of the second service node and the first and the second service nodes; seventh means cooperative with the sixth means for communicating the call traffic of the call between the second service node and the one call processing unit across the packet-switched call path set up for the call on the communication channel between the second service node and the one call processing unit, by using different fixed addresses for different endpoints of every call path to route the call traffic across the channel, so that duplicate copies of the call traffic are communicated between the one call processing unit and the first and the second service nodes when the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node; and eighth means in the one call processing unit cooperative with the second, the need, and the seventh means, for duplicating the call traffic communicated from the telecommunications facility and outgoing to the service nodes and discarding a duplicate of the call traffic incoming from the service nodes and communicated to the telecommunications facility, so that only a single copy of the call traffic is communicated between the one call processing unit and the telecommunications facility when the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node.
Claim 13
Dependent Claim
31 words
The improvement of claim 12 wherein the second and the seventh means each include: means for frame-relaying packets containing the call traffic between a service node and a call processing unit.
Claim 14
Dependent Claim
31 words
The improvement of claim 12 wherein: each address of a call path endpoint located at a service node identifies a wireless channel of the service node which corresponds to the call.
Claim 15
Dependent Claim
31 words
The improvement of claim 12 wherein: each address of a call path endpoint located at the one call processing unit identifies a different logical port of the one call processing unit.
Claim 16
Dependent Claim
28 words
The improvement of claim 12 wherein: each different address of a call path endpoint comprises a different DLCI of LAPD packets carrying the call traffic of the call.
Claim 17
Dependent Claim
59 words
The improvement of claim 12 in a wireless-access telecommunications system that further includes a controller for connecting call processing units to calls, wherein: the recited means all perform their functions without involvement therein of the controller while the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node.
Claim 18
Dependent Claim
64 words
The improvement of claim 12 in a wireless-access telecommunications system that further includes a system controller for coordinating operations of the service nodes and the interface node, wherein: the recited means all perform their functions without involvement therein of the controller while the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node.
Claim 19
Dependent Claim
76 words
The improvement of claim 12 in a wireless-access telecommunications system that further includes an interface node controller for connecting call processing units to calls and a supervisory controller for coordinating operations of the service nodes and the interface node, wherein: the recited means all perform their functions without involvement therein of the controllers while the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node.
Claim 20
Dependent Claim
189 words
The improvement of claim 12 further comprising: ninth means responsive to detection that the mobile user terminal is moving from a vicinity of both the first and the second service nodes to the vicinity of only the second service node, for sending notification thereof from a detecting one of the first and the second service nodes to another one of the first and the second service nodes to indicate transfer of responsibility for the call to solely the second service node; wherein the first means are responsive to the detection by ceasing to communicate call traffic of the call between the first service node and the mobile user terminal; the second means are responsive to the detection by ceasing to communicate call traffic of the call between the first service node and the one call processing unit and by communicating a notification thereof to the one call processing unit across the communication channel between the first service node and the one call processing unit; and the eighth means are responsive to receipt of the notification from the second means by ceasing to duplicate and to discard the call traffic.
Claim 21
Dependent Claim
189 words
The improvement of claim 12 further comprising: ninth means responsive to detection that the mobile user terminal is returning from a vicinity of both the first and the second service nodes to the vicinity of only the first service node, for sending notification thereof from a detecting one of the first and the second service nodes to another one of the first and the second service nodes to indicate transfer of responsibility for the call to solely the first service node; wherein the sixth means are responsive to the detection by ceasing to communicate call traffic of the call between the second service node and the mobile user terminal; the seventh means are responsive to the detection by ceasing to communicate call traffic of the call between the second service node and the one call processing unit and by communicating a notification thereof to the one call processing unit across the communication channel between the second service node and the one call processing unit; and the eighth means are responsive to receipt of the notification from the seventh means by ceasing to duplicate and to discard the call traffic.
Claim 22
Dependent Claim
596 words
In a wireless-access telecommunications system that includes at least one mobile wireless-call user terminal, a plurality of service nodes each for providing wireless-call services to wireless-call user terminals in its vicinity, and at last one interface node connected to the service nodes and having a plurality of call processing units each for interfacing a wireless call that extends between a user terminal and a service node to a telecommunications facility, the improvement comprising: first means in the first service node, responsive to receiving incoming call traffic of the call from a mobile user terminal that is in the vicinity of the first service node, for sending to the interface node first packets containing the received incoming call traffic and each having a first address which identifies the call's corresponding one of the call processing units; second means in the one call processing unit responsive to receiving the first packets, for sending the incoming call traffic contained in the first packets to a telecommunications facility; third means in the one call processing unit, responsive to receiving outgoing call traffic of the call from the telecommunications facility, for sending to the first service node second packets containing the received outgoing call traffic and each having a second address different from the first address and which identifies the first service node; fourth means in the first service node, responsive to receiving the second packets, for sending the outgoing call traffic contained in the second packets to the mobile user terminal; fifth means in the first service node, responsive to a detection that the mobile user terminal is moving from the vicinity of the first service node to the vicinity of the second service node, for sensing to the second service node a message specifying a third address different from the first address and which also identifies the one call processing unit; sixth means in the second service node, responsive to receiving the message, for sending to the interface node a third packet both (a) specifying a fourth address different from the second and the third addresses and which identifies the second service node and (b) having the third address; seventh means in the second service node, responsive to receiving incoming call traffic of the call from the mobile user terminal subsequently to the second service node receiving the message, for sending to the interface node fourth packets containing the received incoming call traffic and each having the third address; eighth means in the one call processing unit, responsive to receiving the third packet, for storing the fourth address for use in the call by the one call processing unit; the third means further responsive to receiving outgoing call traffic of the call from the telecommunications facility subsequently to the one call processing unit receiving the third packet, for sending the second packets to the first service node and also sending to the second service node fifth packets containing same received outgoing call traffic as the second packets and each having the fourth address; ninth means in the second service node, responsive to receiving the fifth packets, for sending the outgoing call traffic contained in the fifth packets to the mobile user terminal; and the second means further responsive to receiving both the first packets and the fourth packets both containing same received incoming call traffic subsequently to the one call processing unit receiving the third packet, for selecting the incoming call traffic contained by one of the received first and fourth packets that contain the same traffic and sending only the selected incoming call traffic to the telecommunications facility.
References Cited (Backward Citations)
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