Note: Descriptions are shown in the official language in which they were submitted.
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Management procedure of a paging system for a
cellular radio paging system.
BACKGROUND OF THE INVENTION
1. Field of the invention
The scope of the invention pertains to cellular radio paging systems, of the GSM type
('Global System for Mobile Communication' in English) for example.
More precisely, the invention concerns a management procedure of a paging systemfor such systems as cellular radio paging systems.
There are numerous applications for the invention, for example, such as the making
available of a completely automatic verbal paging system for all subscribers to a GSM
system.
More generally, the invention may be applied in all instances where due to temporary
unavailability of the subscriber to whom a request for a connection is being made, a caller
wishes to leave a message for this subscriber, this message being delivered to the subscriber
in recorded form.
Here, the term unavailable has several meanings, depending on whether the
subscriber is:
- impossible to get through to: the transmitting/receiving station associated with this
subscriber being out of order (in the off position for example) or even out of the range of the
radio paging system (going through a tunnel for example);
- engaged: it being possible to get through to the subscriber's station (in the sense
defined previously) but he already being on the line;
- not answering: it being possible to get through to the subscriber's station, but the
subscriber not wishing to answer the call.
2. I)escription of the Prior Art
Within prior art, there are different types of management procedures of paging
systems for cellular paging systems.
However, these already known procedures are only completely automatic for a
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subscriber in this sense when the latter wishes to acquaint himself with messages intended
for him, he must take the initiative of calling the paging system then prove his identity by
supplying a password to this paging system. Therefore, there may be a large lapse of time
between the moment when the message is stored by the paging system and the moment when
the subscriber decides to acquaint himself with it. Furthermore, the use of an authentification
procedure using a password is restricting for the subscriber and increases the complexity of
the paging system.
Likewise, neither are these different types of already known management procedures
of paging systems for cellular radio paging systems completely automatic for a caller.
In effect, in the case of a verbal paging system for example, when the subscriber
called is temporarily unavailable, generally the caller must interrupt this connection to ask for
a new connection, sending the latter to the paging system. It is clear that the fact of having to
make a new request for connection, as well as the uncertainty as to the actual moment of the
subscriber acknowledging this message (who he is attempting to through to), often lead the
caller not to leave any message. In this way, existing paging systems often do not encourage
the leaving of messages.
Finally, already known paging systems are generally designed in such a way that
each subscriber is permanently linked to an electronic letter box. As far the paging system is
concerned, this implies the need for large storage message capacities, although their fill rate is
low.
The main aim of the invention is to overcome these various inconveniences of prior
art.
More precisely, one aim of the invention is to supply a management procedure for a
cellular radio paging system, the use of the paging system having to be completely automatic
and easy to use, for the caller as well as for the person being called (only the person being
called has to be a subscriber to a cellular radio paging system).
The aim of the invention is also to supply a procedure which will minimise storage
capacity requirements.
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SUMMARY OF THE INVENTION
These aims, as well as others which will become evident later on, are achieved
according to the invention using a management procedure of a paging system for a cellular
radio paging system in which a subscriber to whom a request for a connection is made is
S likely to be temporarily unavailable,
the said procedure including the following stages:
- detection that the subscriber is temporarily unavailable;
- the said request is sent on to the said paging system;
- the said paging system stores a message intended to be delivered in recorded
form to the temporarily unavailable subscriber;
- the said paging system will automatically recall the said subscriber accordingto a configurable recall strategy, in such a way as to deliver the said stored
message to the subscriber;
the said stage when the message is stored being accompanied by a transmission stage,
using a short message service, of a short message to the temporarily unavailable subscriber.
the said configurable recall strategy consisting of making an immediate attempt at
recalling the subscriber upon receipt of a deferred acknowledgement of the short message,
the said deferred acknowledgement indicating that it is possible to get through to the
subscriber.
In this way, once the subscriber (or person called) is temporarily unavailable the
person making the request (or the caller) sees his request for a connection automatically sent
on to the paging system. Thus, the caller is more easily encouraged to leave a message.
Moreover, due to the paging system automatically recalling the subscriber when anew message is recorded, the acknowledgement of the messages by the subscriber is
effected with minimum delay and without an authentification procedure using a password.
The recall strategy is based on the Short Message Service (SMS). This service
guarantees that it is possible to get through to the subscriber by sending a recorded message
only when the short message stored in the paging system is actually received by the
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subscriber.
To its advantage, the said recall strategy also consists of systematically recalling the
subscriber predetermined periods of time after the said instantaneous attempt, when it is
possible to get through to the subscriber although he is still unavailable,
the said predetermined periods of time being a function of at least one of the
following parameters:
- the time;
- the date;
- the type of unavailability of the subscriber, including 'engaged' or 'not
replying'.
In effect, the SMS guarantees only that it is possible to get through to the subscriber,
even though the subscriber may already be on the line or may even have decided not to reply.
Advantageously, the said recall strategy also consists of systematically recalling the
subscriber predetermined periods of time after the moment of detecting that the subscriber is
temporarily unavailable.
With regard to the paging system, therefore, the recall strategy also consists of
attempting to get through to the subscriber at parametered intervals of time, until
communication is made and the message(s) delivered.
Advantageously, the said predetermined periods of time are a function of at least one
of the parameters from the group including:
- the time;
- the date;
- the type of unavailability of the subscriber, including 'impossible to get
through to', or 'engaged' or 'nor replying'.
Thus, for example, the duration of the two attempts at recall is longer when it is
impossible to get through to the subscriber than when he is engaged.
It is preferable for the said storage stage of a message to consist of recording the said
message in a storage zone linked biuniquely to the subscriber,
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the said storage zone being created dynamically when, on one hand, no other storage
zone is associated with the said subscriber and on the other hand, the said message intended
for the said subscriber must be stored.
Thus, a storage zone corresponds to the subscribers' personal 'letter box' only if a
S message addressed to the latter must be stored.
Preferentially, the invention procedure also includes an stage for erasing the said
message stored in the said storage zone,
the said storage zone being suppressed dynamically when it contains no more
messages.
In this way, storage resources are optimised since on one hand, a storage zone is only
created if there is a message to be stored, and on the other hand, a storage sone is suppressed
when it contains no more messages.
To its advantage, the said storage zone may contain two types of messages, including
messages supposed to have been delivered to the subscriber and messages not supposed to
have been delivered to the subscsiber,
the said erase stage occurring at the end of a precise period of time depending on the
type of message.
In effect, messages which the subscriber has not yet acquaintd are generally
conserved longer than messages already delivered (or supposed to have been delivered).
In a preferential mode of production of the invention, the said recall strategy also
consists of detecting an auto call of the said paging system, the said auto call being a request
for a connection to the subscriber from the said paging system and sent to the said paging
system when the subscriber has been detected as being temporarily unavailable, a detected
auto call being cut off.
Advantageously, the detection of an auto-call consists on one hand, of comparing the
information contained in the 'identity of the caller line' field and 'address of person called'
field of the initial address message (MIF) accompanying the said recall of the subscriber by
the paging system and having a signalling function, and, on the other hand, of analysing the
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information contained in the 'indicator of call sent on' field of the said initial message
address.
Advantageously, the said storage zone has an address number calculated from
information characterising the said subscriber.
S In a preferential mode of production of the invention, the said characteristic
information concerning the said subscriber includes the telephone number of the said
subscriber, and the calculation of the said address number of the storage zone consists:
- of windowing the subscriber's said telephone number by p]acing a justified
window on the last figure of the said telephone number, then
- of sub-windowing the said window by placing minus a first and second sub-
window in the said window, the said address number being obtained by concatenating on
one hand either the number contained in the second sub-window or a reduced number
deducted from the number contained in the said second sub-window and on the other hand
either the number contained in the said first sub-window or a reduced number deducted from
the number contained in the said first sub-window.
Advantageously, the said subscriber's telephone number has nine figures and is
written ZABPQMCDU, the said window contains the number BPQMCDU, the said first
sub-window contains the number BPQ, the said second sub-window contains the number
MCDU, and the said address number is:
- either BPQMCDU, if the number BPQ contained in the first sub-window is
conserved;
- or xyz MCDU if the Number BPQ contained in the first sub-window is
replaced by the reduced number xyz;
- or even xyz abcd if it is necessary to modify the content of the two sub-
windows, due to the already allocated numbers BAZ.
Advantageously, the said characteristic information pertaining to the said subscriber is
the information contained in the 'identity of the first person called' field of the initial message
address (MIF) accompanying the said request for connection sent on to the paging system
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and having a signalling function.
In this way, the MIF signalling message is used to authenticate the subscriber. Most
notably the initial message address (MIF) contains information fields concerning the caller,
the first person requested (in the event of a call being sent on) and the person being
S requested.
In the event of a request for connection being sent on to the paging system: the caller
is the correspondent who is attempting to get through to the subscriber, and the 'person'
being requested is the paging system.
Thus, in the case of a GSM network where each subscriber is wholly identified bythe parameters of his SIM card (Subscriber Identity Module in English), the MIF is linked
biuniquely to the SIM card and may therefore be used as an authenticator for this SIM card
(and by the same subscriber).
Preferentially, during automatic recall of the said subscriber, the said subscriber's
telephone number is calculated by the said paging system based on the said address number
in the storage zone.
In a preferential mode of production of the invention, the invention procedure
includes a stage where the subscriber is called by the paging system, in order that the said
subscriber may acquaint himself with at least one possible message.
In this instance, the subscriber calls the paging system directly. This will allow him to
consult the messages for example.
Advantageously, during the said stage when the subscriber calls the paging system,
the said address number in the storage zone is located by the said paging system based on the
said characteristic information on the said subscriber, the said characteristic information on
the said subscriber being contained in the 'identity of the caller line' field of the initial
message address (MIF) accompanying the said paging system by the subscriber and having a
signalling function.
Thus, as in the case of the subscriber being recalled, management of the paging
system is completely automatic during the stage when the subscribe calls the paging system.
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In other words, use of the information contained in the MIF avoids use of the password or
any other authentification procedure by the subscriber.
In a preferential mode of production of the invention, the invention procedure
includes an enabling/disenabling stage of the said storage zone to which the said subscriber is
linked biuniquely, disenabling and enabling respectively consisting of inhibiting and
authorising respectively, the said automatic recall stage by the said subscriber.
Advantageously, the said cellular radio paging system is a GSM system (Global
System for Mobile Communications).
Advantageously, the said message belongs to the group including:
- verbal messages;
- faxes;
- consultation of data bases.
It is clear however, that the procedure according to the invention is not linked to a
particular type of message.
RIEF DESCRIPTION OF THE DRAWINGS
Other characteristics and advantages of the invention will be revealed on reading the
following description of a preferential mode of production of the invention given by way of
an example and not limiting, and of the drawings contained in the appendices, in which:
- figures 1 to 4 each present a diagram showing the functioning of a paging
system for a cellular radio paging system, this paging system being authorised by a
procedure according in accordance with the invention, figures 1 to 4 corresponding
respectively in the event of:
* a request for a connection sent to a subscriber by a correspondent being sent
on to the paging system;
* a request for a connection is sent to a subscriber by the paging system;
* a request for a connection is sent to the paging system by a subscriber;
* a connection request sent to a subscriber by the paging system being sent on to the paging system.
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- figure 5 shows a flow chart describing the functioning of the paging system
as a function of the different types of connection received;
- figure 6 shows a flow chart describing an initial message address of the type
used in a preferential mode of production of the invention;
- figures 8A, 8B and 8C each show an example of a calculation of an address
number for message storage, it being possible for each of these three examples to
implemented in management of a paging system in accordance with the invention.
MORE DETAILED DESCRIPIION
The invention concerns therefore, an management procedure of a paging system for a
cellular radio paging system. It involves offering each subscriber to this radio paging system
a completely automatic, sound and easy to use paging system.
The description which follows concerns a preferential mode of production of the
procedure in accordance with the invention as applied to a verbal paging system reserved for
subscribers to the GSM system (Global System for Mobile Communications).
It is clear that the invention is not limited only to this application. Generally,
messages processed by the paging system authorised by the invention procedure may be of
any type (verbal messages, faxes, consultation of data bases, etc...). Likewise, the procedure
in accordance with the invention of authorising a paging system may be implemented by all
types of cellular radio paging systems.
In the GSM system, each subscriber is associated with a mobile station allowing him
to make or receive calls whilst moving around a predetermined area. This space in which the
mobile stations operate is broken down into a network of adjacent cells. A distinct
transmission/reception base station is associated with each cell. The base stations are linked
to a communication centre (or MSC for 'Mobile Switching Centre' in English), which
ensures connection between a GSM subscriber and a distant subscriber (who is, for example,
a subscriber to the public telephone system (RTCP) or another GSM subscriber).
Figures 1 to 4 each show a diagram showing the functioning of a verbal paging
system for a GSM system, this paging system being authorised by a management procedure
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in accordance with the invention.
Figure 1 co}Tesponds to the case of a request for a connection with a subscriber 1 by
a correspondent, and sent on to paging system 2.
In this example, we suppose that the correspondent is an RTCP subscriber . The
S correspondent's call arrives (11) in an initial GMSC communication centre acting as an
interface between the RTCP and the GSM network. Then this call is routed (12) on the GSM
to a second VMSC communication centre capable of allowing (13) the request for the
correspondent's connection to reach the subscriber 1 (that is, the mobile station).
If we suppose that the subscriber 1 is temporarily unavailable at that time, unavailability is
detected and, due to a call return device (14), the request for a connection is again routed (15)
to another MSC communication centre which will allow (16) this request to be entered in the
paging system 2.
In addition, the paging system offers the correspondent the possibility of leaving a
message, this message being stored in order to be delivered to the temporarily unavailable
subscriber.
Figure 2 corresponds to the case of .he paging system 2 recalling the subscriber 1.
During this completely automatic recall, the request for a connection issued by paging system
2 is routed (21) to the MSC communication centre, then this request is routed (22) to the
VMSC communication centre, prior to arriving (23) at the subscriber 1.
Figure 3 shows the case of the subscriber 1 calling the paging system 2. During this
call, made at the subscriber's own initiative, the request for a connection made by the
subscriber is routed (31) to the VMSC communication centre, then this request is routed (32)
to the MSC communication centre, prior to arriving (33) at the paging system 2.
Thus, even if, during normal working, the paging system automatically recalls the
subscriber in order to deliver the stored message(s), the subscriber is offered the possibility
of recalling the paging system in order to acquaint and messages.
Figure 4 corresponds to the case of an auto call by the paging system 2. This is when
the paging system attempts to get through to the subscriber, or when the call is sent on to him
ù t . , ` ~ : 'A ~ ~ ~
21261 71
because he is unavailable.During an auto call, a request for a connection issued by the paging
system is routed (41) to the MSC communication centre, then this request is routed (42) to
the VMSC communication centre capable of allowing (43) the paging system's request for a
connection to reach thei subscriber. If we suppose that the subscriber 1 is temporarily
unavailable at this time, unavailability is detected by a call return device (44), the request for a
connection is again routed (45) to the MSC communication centre which allows (46) this
request to be entered in the paging system 2. Such an auto call is cut off by the paging system
as soon as it is detected.
During the stage when the message is stored in the paging system, the message isrecorded in a storage zone biuniquely linked to the subscriber. In the example of a verbal
message, each storage zone is a verbal 'letter box' temporarily allocated to a subscriber. The
verbal boxes are created dynamically: this is only when, on one hand, a message intended for
a subscriber must be stored and on the other hand, when this subscriber does not already
have a box the paging system creates a box intended for this subscriber.
Each verbal box has an address number calculated from characteristic informationpertaining to the subscriber to whom it is linked biuniquely.
Figures 8A, 8B and 8C each show an example of a calculation of a box number in thei
case of the subscriber's characteristic information being composed of the subscriber's
telephone number. In the following, we will take an example of a nine figure number written
ZABPQMCDU.
In the three examples (figures 8A, 8B and 8C), a justified window 81 is placed on the
last figure (U) of the telephone number and containing seven figures. This window therefore
contains the number BPQMCDU. Then, window 81 is sub-windowed by placing two sub-windows there 82, 83.
The first sub-window 82 contains the number BPQ and the second sub-window 83
contains the number MCDU.
In the example shown in figure 8A, the number of verbal box 84 is obtained by
concatenating the numbers contained in the two sub-windows 82, 83. The number of verbal
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box number 84 is therefore BPQMCDU.
In the example shown in figure 8B, the number of verbal box 85 is obtained by
concatenating the number contained in the second sub-window 83 and a reduced number 86
(xyz) deducted from the number contained in the first sub-window 82. The number of verbal
box 85 is therefore xyzMCDU.
In the example shown in figure 8C, the number of verbal box 88 is obtained by
concatenating on one hand a reduced number 86 (xyz) deducted from a number contained in
the first sub-window 82 and on the other hand, a reduced number 87 (abcd) deducted from
the number contained in the second sub-window 83. The number of verbal box 88 is therefore xyz abcd.
Inversely, when the paging system recalls the subscriber, the subscriber's telephone
number is calculated from the verbal box number. The paging system includes for example a
table linking the telephone numbers and verbal box numbers.
According to the invention, the messages stored in a box are erased at the end of
predetermined periods. A box being suppresses (which means that is available for another
subscriber) as soon as it contains no messages.
With regard to the erasing of messages, we make a distinction between two types of
message: messages supposed to have been delivered to the subscriber and messages not
supposed to have been delivered to the subscriber. Messages supposed to have been
delivered to the subscriber, which are messages which the subscriber has actually listened to
or messages that he has not completely listened to are, for example, erased after a period of
two hours. Messages not supposed to have been delivered to the subscriber which are
messages received since the last call the subscriber made to the paging system (or even since
the last call to the paging system by the subscriber if this call is more recent than the call cited
previously), are conserved longer, a week for example.
In the preferential mode of production of the invention described below, the initial
message address (MIF) is used, which is No 7 a CCITT signalling message accompanying
each communication made on the fixed numeric network or the GSM network. This MIF
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passes through the semaphore network when a communication is being initiated. The user
sub-system generally implemented is the SSUTR2, the specifications for this having been
drawn up by the CNET (National Telecommunications Study Centre). Thus, in the case of a
GSM system, each subscriber is identified by an electronic card (SIM - Subscriber Identity
Module) which enables the authentification of its call requests. These requests are carried by
the GSM network with the MIF as identifier.
As shown in simplified form on figure 7, an MIF 71 includes especially:
- an 'identity of the caller line' field 75 (A);
- an 'identity of the first person called' field 74 (B);
- an 'address of the person called' field 73 (C);
- an 'indicator of the call sent on' field 72 (D).
When the subscriber receives a call from a correspondent, even though he is
temporarily unavailable, the incoming call is sent on to the paging system. This return is
programmed in the network to a fixed return number which corresponds to the paging system
access number. The corresponding MIF number is therefore:
- the 'indicator of the call sent on' field indicates that a call has been sent on;
- the 'identity of the caller line' 75 most notably contains the correspondent's telephone number;
- the 'identity of the first person called' 74 most notably contains the mobile
subscriber's telephone number;
- the 'indicator of the call sent on' 72 most notably contains the telephone
number of the verbal paging system.
When the request is sent on to the paging system, the paging system uses the
information contained in the 'identity of the first person called' field (field B) of the M~F to
calculate a verbal box number (examples of such a calculation were explained previously in
relation to figures 8A and 8B).
When the subscriber calls the paging system, the MIF is:
- the 'identity of the caller line' 75 most notably contains the subscriber's
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telephone number;
- the 'identity of the person called' 73 most notably contains the paging
system's telephone number.
In the case of a call to the paging system by the subscriber, the paging system uses
S the information contained in the 'identity of the caller line' (field A) of the MIF to calculate
the subscriber's verbal box number.
In the case of an auto call to the paging system, the corresponding MIF is one of:
- the 'call sent on indicator' field indicates that the call has been sent on;
- the 'identity of the caller line' 75 field most notably contains the paging
system telephone number;
- the 'identity of the first person requested' 74 most notably contains the
subscriber's telephone number;
- the 'address of the person requested' 73 contains most notably the paging
system's telephone number.
The paging system detects an auto call:
- on one hand by comparing the information contained in the 'identity of the
caller line' and 'address of the person requested'; and
- on the other hand, by analysing the value of the 'indicator of the call sent on'.
Figure 5 shows an example of a flow chart describing the functioning of the paging
system as a function of the different types of call received.
With any type of connection, the paging system receives 51 an MIF. The analysis 52
of this MIF (and especially the information contained in fields A,B,C, and D) enables the
type of call to be determined, including:
- 'call sent on' 53: a call to a subscriber by a correspondent est sent onto thepaging system;
- 'direct interrogation by the mobile' 54: the subscriber calls the paging system;
- 'auto call' 55: the call to a subscriber from the paging system is sent onto the
paging system.
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In the case of a 'call sent on' 53, the paging system calculates 56 a verbal box number
BV based on field B (that is, the 'identity of the first person called' field) of the MIF, then
checks 57 that this box already exists (and creates one 58 if the opposite is the case), and
finally places 59 the message in the box.
In the case of 'direct interrogation by the mobile' 54, the paging system calculates
510 a verbal box number based on field A (that is, the 'identity of the caller line') of the MIF,
then checks 511 that this box number is valid, and communicates 513 its messages to the
subscriber if this is the case or even cuts off 512 the call if the opposite is the case.
Figure 6 shows an example of a flow chart demonstrating the mechanism used by the
paging system for recalling a subscriber. This mechanism enables a choice to be made 62
between two distinct recall strategies, once the paging system has calculated 61 the
subscriber's telephone number from his vocal box number.
An initial recall strategy is cased on the use of an SMS service (Short Message
Transmission Service). The SMS guarantees the transmission of a short message (of several
tens of octets for example), reception of this short message by the mobile (that is, the
subscriber) being proven by means of a message received message (or acknowledgement of
reception).
It should be noted that the SMS enables determination of whether or not it is possible
to get through to the subscriber, a subscriber who it is impossible to get through to if his
station is switched off or out of range of the system (outside of the zone covered or in a
tunnel for example). However, the subscriber may still be temporarily unavailable: either
because his line is already engaged, or because he does not want to answer.
In the case of a verbal message, a short message is systematically sent 63 to the
subscriber once a ve~bal message has been left. Once the acknowledgement of receipt has
been received 64, it is once again possible to get through to the subscriber, and the verbal
paging system may call him back 65.
If the subscriber is already on a call or does not want to reply, the call cannot be
successful. Consequently, the paging system 66 calls again several times (including an initial
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call upon receipt of the message received message, and then at intervals), until the subscriber
can acquaint his messages 67.
The intervals between call attempts are based on the time, the date and type of
unavailability of the subscriber (according to whether he is already on the line or does not
S want to reply).
A second recall strategy, which may eventually be used alongside the first, consists
of attempting to get through 68 to the subscriber at predetermined intervals from the moment
where it was detected that the subscriber is temporarily unavailable, and this until the
subscriber can acquaint 69 his messages.
The intervals of time are, for example, based on the time, the date and type of
unavailability of the subscriber. According to whether it is impossible to get through to the
subscriber, or already engaged, increasing intervals of time are taken respectively, for
example, of S rninutes, lO minutes, 30 minutes, 1 hour, 12 hours and so on, and constant
intcrvals of time (in minutes).
We could also foresee the possibility of the subscriber being able to disenable his
verbal box, if he no longer wanted to automatically receive messages intended for him. The
potential of re-enabling the his verbal box in the future also being provided.
It should be noted that for the correspondent, sending on of the call to the paging
system is automatic and, following a message given by paging system upon receipt, he only
has to leave his message. Likewise, the subscriber may consult his messages automatically;
when the paging system has got through to him (or the reverse), he only has to listen to the
messages played to him by the paging system.
This mechanism is governed by the absence of lhe DTMF code (Detection of Multi
Frequency Keys). However, it is clear that in a variation of the invention, we foresee the
possibility of using the DTMF for example, to supply a option enabling playback and
modification of a recorded message.
~' ' : ' : :
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