Communications system

Claim 2

A communications system, comprising: a network formed by a plurality of geographically distributed interconnected nodes, each defining a service area; means interconnecting the nodes; a plurality of subscriber units; means for storing registration details of a subscriber unit at one of said nodes, defined as a home node; and means responsive to a subscriber unit registering with a node other than its home node for causing registration details relating to that subscriber unit to be stored at those of said interconnected nodes lying on a path between said home node and the node at said subscriber unit registered.

Claim 3

A system as claimed in claim 1, characterised in that in response to a subscriber unit registering with a node, any node or nodes carrying registration details of the subscriber unit but not lying on the path of interconnected nodes between the home node and said node with which said subscriber unit registered, deregisters the subscriber unit.

Claim 4

A system as claimed in claim 1 characterised in that when a subscriber unit wishes to set-up a call through a first node with another subscriber unit registered on a second node, said first node has means for initiating relaying of a call request node by node through the network and each intermediate node has means for checking if the registration record of the another subscriber unit is contained therein, and in response to determining that the registration record of the another subscriber unit is contained therein, said means for relaying of the intermediate node containing the registration record actuates means for initiating a call request along the path to the node at which the another subscriber unit is currently registered, and in receipt of an acknowledgment, connects the subscriber units together and notifies a home node of said another subscriber unit by way of intermediate nodes on the path.

Claim 5

A system as claimed in claim 1, characterised in that a node has means for processing a request from a first subscriber unit to monitor a call made by a second subscriber unit registered with another node, in that the node with the processing means has means for progressing said monitoring request node by node to a node on the path to said another node, in that each node of the path has means for recording the address of the node processing the monitoring request and for propagating said address to other nodes in the network.

Claim 6

A system as claimed in claim 1, characterised in that at least 2 subscriber units form a group having a group registration identity, in that at least one of said nodes comprises means, responsive to a subscriber unit belonging to a group registering with the at least one node, for checking if the group is already registered with the at least one of said nodes, and if the group is not registered, for registering the group registration with the the at least one of said nodes.

Claim 7

A system as claimed in claim 5, characterised in that said means for checking and registering is also responsive to a subscriber unit having a group registration identity being deregistered for checking if the at least one of said nodes has remaining registered therewith any other subscriber units having the same group registration identity as that of said subscriber unit being deregistered and if not, for deregistering the group.

Claim 8

A system as claimed in claim 5, characterised in that the at least one of said nodes has means for initiating a group call in response to a request received thereat.

Claim 9

A system as claimed in claim 7, characterised in that each said means for initiating a group call propagates the call to all the nodes forming a coverage tree of the group whereupon the call is set up on receipt.

Claim 10

A system as claimed in claim 7, characterised in that each said means for initiating a group call propagates a call request to all the nodes forming a coverage tree of the group and in that one of said nodes propagates a connect instruction to the other nodes forming the coverage tree.

Claim 11

The communication system as claimed in claim 1 wherein said registration details stored in those of said interconnected nodes lying on a path between said home node and the node at which said subscriber unit registered are sufficient to validate said subscriber unit for the initiation of a call without requiring any other information from the home node of said subscriber unit.

Claim 12

A communications system for use in serving a plurality of subscriber units, comprising: a network formed by a plurality of geographically distributed nodes, each defining a service area; means for storing registration details of a subscriber unit at one of said nodes, defined as a home node therefor; and means, responsive to said subscriber unit registering with a node other than said home node, for causing registration details relating to said subscriber unit to be stored at those of said interconnected nodes which lie on an interconnected path between said home node and the node at which said subscriber unit registered.

Claim 13

A communications system for use in serving a plurality of subscriber units, comprising: a network formed by a plurality of geographically distributed nodes, each defining a service area; means for storing registration details of a subscriber unit at one of said nodes, defined as a home node therefor; and means, responsive to said subscriber unit registering with a node other than said home node, for causing registration details relating to said subscriber unit to be stored at those of said interconnected nodes which lie on an interconnected path between said home node and the node at which said subscriber unit registered.

Claim 14

A particular node for use in a communications system for use in serving a subscriber unit, said communications system including a network formed by interconnecting a plurality of geographically distributed nodes, each of said nodes defining a service area, said particular node being one of said nodes, said subscriber unit being assigned to one of said nodes as a home node, said particular node comprising: means for communicating with at least two others of said nodes, including means (i) for receiving from a first of said at least two other nodes registration details relating to said subscriber unit, and (ii) for transmitting said received registration details to a second of said at least two other nodes; and means for storing registration details relating to that subscriber unit when (a) said subscriber unit registers with a node other than its home node, (b) said particular node lies on a path of interconnected nodes between said home node and said node at which said subscriber just registered, and (c) said particular node is not said home node nor said node at which said subscriber just registered.

Claim 15

A particular node for use in a communications system for use in serving a subscriber unit, said communications system including a network formed by interconnecting a plurality of geographically distributed nodes, each of said nodes defining a service area, said particular node being one of said nodes, said subscriber unit being assigned to one of said nodes as a home node, said particular node comprising: means for communicating with at least two others of said nodes, including means (i) for receiving from a first of said at least two other nodes registration details relating to said subscriber unit, and (ii) for transmitting said received registration details to a second of said at least two other nodes; and means for storing registration details relating to that subscriber unit when (a) said subscriber unit registers with a node other than its home node, (b) said particular node lies on a path of interconnected nodes between said home node and said node at which said subscriber just registered, and (c) said particular node is not said home node nor said node at which said subscriber just registered.

Claim 16

A particular node for use in a communications system for use in serving a subscriber unit, said communications system including a network formed by a plurality of geographically distributed interconnected nodes each of which defines a service area, said particular node being one of said nodes, said subscriber unit being assigned to one of said nodes as a home node, said particular node comprising: means for receiving registration details relating to said subscriber unit when said particular node lies on a path of interconnected nodes between said home node and a node at which said subscriber unit most recently registered when said particular node is not said home node nor said node at which said subscriber unit most recently registered; means for storing said received registration details substantially only while said particular node continuously remains part of a path of interconnected nodes between said home node and said node at which said subscriber unit most recently registered.

Claim 17

A particular node for use in a communications system for use in serving a subscriber unit, said communications system including a network formed by a plurality of geographically distributed interconnected nodes each of which defines a service area, said particular node being one of said nodes, said subscriber unit being assigned to one of said nodes as a home node, said particular node comprising: means for receiving registration details relating to said subscriber unit when said particular node lies on a path of interconnected nodes between said home node and a node at which said subscriber unit most recently registered when said particular node is not said home node nor said node at which said subscriber unit most recently registered; means for storing said received registration details substantially only while said particular node continuously remains part of a path of interconnected nodes between said home node and said node at which said subscriber unit most recently registered.

Claim 18

A particular node for use in a communications system for use in serving a subscriber unit, said communications system including a network formed by a plurality of geographically distributed interconnected nodes each of which defines a service area, said particular node being one of said nodes, each of said subscriber units being assigned to one of said nodes as a home node, said particular node comprising: a transceiver; and means, responsive to a subscriber unit registering with a node other than its home node, for storing registration details relating to that subscriber unit substantially only while (i) said particular node lies on a path of interconnected nodes between said home node and a node at which said subscriber unit most recently registered and (ii) said particular node is not said home node nor said node at which said subscriber unit most recently registered.

Claim 19

A particular node for use in a communications system for use in serving a subscriber unit, said communications system including a network formed by a plurality of geographically distributed interconnected nodes each of which defines a service area, said particular node being one of said nodes, each of said subscriber units being assigned to one of said nodes as a home node, said particular node comprising: a transceiver; and means, responsive to a subscriber unit registering with a node other than its home node, for storing registration details relating to that subscriber unit substantially only while (i) said particular node lies on a path of interconnected nodes between said home node and a node at which said subscriber unit most recently registered and (ii) said particular node is not said home node nor said node at which said subscriber unit most recently registered.

Claim 20

A communications system, comprising: a network formed by a plurality of geographically distributed nodes, each defining a service area; a plurality of subscriber units; means for storing registration details of a particular subscriber unit at one of said nodes, defined as a home node for said particular subscriber unit; and means, responsive to said particular subscriber unit registering with a particular node which is other than its home node, for causing registration details relating to said particular subscriber unit to be stored at those of said nodes lying on an interconnected path between said home node and the particular node at which said registration occurred.

Claim 21

A communications system, comprising: a network formed by a plurality of geographically distributed nodes, each defining a service area; a plurality of subscriber units; means for storing registration details of a particular subscriber unit at one of said nodes, defined as a home node for said particular subscriber unit; and means, responsive to said particular subscriber unit registering with a particular node which is other than its home node, for causing registration details relating to said particular subscriber unit to be stored at those of said nodes lying on an interconnected path between said home node and the particular node at which said registration occurred.

Claim 22

A system as claimed in claim 15, characterised in that in response to said particular subscriber unit registering with said particular node, any node or nodes carrying registration details of said particular subscriber unit but not lying on the path of interconnected nodes between the home node and said particular node, deregisters said particular subscriber unit.

Claim 23

A system as claimed in claim 15 wherein each node along a connected path between said particular subscriber unit and another subscriber unit of said plurality of subscriber units registered at one of said nodes comprises: means for receiving a request for a call between said particular subscriber unit and said other subscriber unit; means responsive to receipt of said call request for making a determination as to whether or not the node that received the call request carries the registration record of said other subscriber unit; and means for initiating a call request along the path to the node at which said other subscriber unit is currently registered, said initiating being in response to a determination that it has the registration record of said other subscriber unit.

Claim 24

A node for use in a communications system formed by a plurality of geographically distributed nodes, each defining a service area, said node comprising: means for interconnecting said node to at least one other node; means adapted for coupling said node to at least one subscriber unit; means for storing registration details of a particular subscriber unit for which said node is defined as a home node; and means, responsive to another of said subscriber units registering with any node of said communication system that is not a home node for said other subscriber unit, for initiating the storage of registration details relating to said another subscriber unit in at least one of said nodes lying on a path between said home node and the node at which said another subscriber unit registered.

Claim 25

A node for use in a communications system formed by a plurality of geographically distributed nodes, each defining a service area, said node comprising: means for interconnecting said node to at least one other node; means adapted for coupling said node to at least one subscriber unit; means for storing registration details of a particular subscriber unit for which said node is defined as a home node; and means, responsive to another of said subscriber units registering with any node of said communication system that is not a home node for said other subscriber unit, for initiating the storage of registration details relating to said another subscriber unit in at least one of said nodes lying on a path between said home node and the node at which said another subscriber unit registered.

Claim 26

The invention as defined in claim 18 wherein said path is a non-hierarchical path.

Claim 27

The invention as defined in claim 18 wherein said registration details are sufficient to validate a subscriber unit for the initiation of a call without requiring any other information from the home node of said subscriber unit.