Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
1997-02-21
2004-07-20
Yao, Kwang Bin (Department: 2667)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S384000
Reexamination Certificate
active
06765886
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to call set-up and service invocation in telecommunications networks, in particular to Intelligent Networks (IN)-based mobile telecommunications networks.
2. Description of Related Art
There is currently considerable activity in international standards bodies (CCITT, ISO, etc.) and elsewhere in developing Intelligent Network standards and implementations. Put simply, the basis of an intelligent network is to separate service provision from switching functionality in telecommunications networks. Typically, the processing required to implement network services is provided by processors which are physically and logically separate from the switching infrastructure and control it. This allows for rapid creation and introduction of new services without their design or implementation being excessively constrained by the characteristics of the network switches. In particular, a service may be provided throughout a network without the need to modify every individual network switch.
In present day IN standards (CCITT Capability Set
1
(CS
1
) and implementations the logical platform for launching all IN services is a “Basic Call State Model” (BCSM) modelled in the software of each IN switch in a network. The BCSM defines a finite number of states in the lifetime of a telecommunication call, e.g. off-hook, collect digits, etc. Within the BCSM a number of Detection Points (DPs) are identified, at which certain events can trigger a switch to suspend its call processing and refer to service control entities for further instructions and service-request processing. The service control entity can then control the switch to allow it to continue, terminate or modify its call processing according to the service requested.
Service control entities are able to modify the call processing by performing further processing. For example:
a) Performing checks upon the validity and account details of the calling user's identity;
b) Obtaining further information to aid call completion: this may include obtaining the routing number, comparing service requests for compatibility, and checking the called party's status, e.g. whether already engaged on another call, and whether diversion or a mailbox facility is available.
If a service control entity determines from these further processing steps that a call is to be made, it then returns control of the call to the switch and the call set-up continues with routing, alerting and answer. The elements of the call set-up procedure may have been modified by the service control entity, e.g. if a call diversion is in operation for the called number, or differentiated ringing tones are in use by the called party for different calling numbers. All service and call requests are initially handled by the switch, the operation of the service control entity being determined by the current status of the switch's BCSM.
Intelligent Networks have great potential for offering advanced network services in the future. It has been proposed to use these principles as the basis for future mobile telecommunication systems (as well as fixed systems) and while a number of enhancements needed to achieve this have already been identified, further changes will be required. A number of systems have been developed to make use of IN principles to provide more efficient call connections and other, non-call, services. In particular, reference is made to Patent Specifications WO93/16543 (Ericsson), and U.S. Pat. No. 4,910,766 (Ogino), and Giridharagopal: “Intelligent Networks; Demands on Provisioning and Performance”:
Proceedings of the
12
th InternationalTeletraffic Congress
, No 1, 1989 (Amsterdam), pages 447 to 454. The systems described in these documents all route service requests, by way of a local switch, to a “Service Control Centre” which then controls further trunk switching, or other services.
A generalised description of these current techniques of intelligent network call set-up is illustrated schematically in
FIGS. 1
a
and
1
b
. As shown in
FIG. 1
a
the logical interconnection of the schematically illustrated telecommunications network is as follows: a terminal
1
is connected to a switch
2
by a communications link
4
, and the switch
2
is connected to a service control unit
3
by means of a control link
6
, and to other terminals
8
, by means of a communications link
5
, either directly or through other switches. The logical communications links
4
,
5
are carried over physical links, which may be permanent (wired) links to fixed terminals or may be dynamically variable links having no permanent physical existence except when required to form a communications connection, for example the radio links in a mobile radio network, or the links in the fixed trunk network (in which the individual physical links are only allocated to individual end-to-end calls for the duration of those calls).
FIG. 1
b
shows a flow diagram for the operation of the system of
FIG. 1
a
. A call or other service request is directed by a user from the terminal
1
to the switch
2
(step
21
), over the communications link
4
. If a call request is made requiring further processing, the switch recognises this and switch processing is interrupted (step
22
). The switch
2
then directs such a request for further processing of the call to the service control unit
3
(step
23
), by way of the control link
6
. The service control unit
3
provides the checking and further computation required to create instructions for the switch
2
to complete the call request or to perform some other service request (step
24
). In the case of a call request, the service control unit
3
then returns the required instructions to the switch (step
25
) to enable the call to be routed and completed (step
27
), by allocating a further communications link
5
in order to complete the communications connection. In practice there will be several interconnected switches
2
, each serving a number of terminals
1
, and each having access to one or more service control units
3
providing different services. The remote terminal
8
is then alerted to the call and responds (step
28
).
On initiation of a request for a call or other transaction (e.g. a service request) a communications connection, capable of carrying both signalling and call traffic, is established using the communications link
4
between the terminal
1
and the switch
2
. Resources in the switch
2
are then dedicated to completion of the connection required. However, the resources may not be required if the service processing step
24
determines that the communications connection
5
to the remote terminal
8
is not to be completed. When the switch
2
requests processing from the service control unit
3
, the service control unit
3
may fail the call and cause the switch
2
to release the connection link
4
due to a service mismatch, customer specific service (such as outgoing calls barred) or called party terminal state (such as the busy condition). This will mean that, in addition to a signalling channel, a traffic channel will have been connected on the communications link
4
from the user terminal
1
to the switch
2
and in the switch
2
itself, and then not used. For a mobile telecommunications system, such as a cellular radio system, this is of significance because the communications link
4
is not permanently allocated to the terminal
1
as it would be in a fixed system. Instead, a radio channel is only allocated when a terminal
1
requires it. Whilst allocated to one call attempt, these resources cannot be used by other call attempts, which may then fail for lack of available capacity.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a switched mobile telecommunications network for providing communications connections between mobile network terminations and other network terminations, the network comprising:
one or more mobile network terminations;
service processing means for providin
Cullen John M.
Lobley Nigel
British Telecommunications plc
Yao Kwang Bin
LandOfFree
Call set-up and service invocation in telecommunications... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Call set-up and service invocation in telecommunications..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Call set-up and service invocation in telecommunications... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3254297