WO2006136375A1

WO2006136375A1 - Reconfigurable quality of service monitoring for messaging in mobile communications networks

Info

Publication number: WO2006136375A1
Application number: PCT/EP2006/005913
Authority: WO
Inventors: Thorsten Trapp; Christoph Begall; Peter Jung; Andreas Waadt; Guido Bruck
Original assignee: Tyntec Ltd.
Priority date: 2005-06-20
Filing date: 2006-06-20
Publication date: 2006-12-28
Also published as: GB2446913B; GB2446913A; GB0512477D0; GB0800853D0

Abstract

In mobile environments, packet transmission services suffer from packet losses due to e.g. inadequate received signal quality, which is caused by the time and frequency selectivity of the mobile radio channel and by imperfections of mobile terminals, but also due to time-outs and entailed packet deletions, forced by protocols in the signaling domain of the infrastructure of a mobile communications network. To reduce the impact of packet losses and, hence, to improve the quality of packet transmission services, such as e.g. the Short Message Service (SMS) deployed in GSM (Global System for Mobile Communications) and in GPRS (General Packet Radio Service) based mobile communications networks, a quantitative analysis of the Quality of Service (QoS) in the signaling domain is mandatory. For this reason, appropriate additional QoS parameters, which complement the presently existing set of QoS parameters defined by e.g. ETSI, are needed. In this communication, the authors propose such QoS parameters and apply them to the SMS in GSM networks. Furthermore, a system framework for QoS monitoring, alerting and reconfiguring an SMS Center is presented. The system framework operates near real-time and, therefore, facilitates the reduction of the turnaround time needed for necessary reconfigurations at the SMS Center to maintain a high QoS level. Also, selected monitoring results gathered during real world network operation are presented and discussed.

Description

Reconfigurable Quality of Service Monitoring for Messaging in Mobile Communications

Networks

Field of the invention

The invention relates to a method and apparatus for determining the quality of service of the transmission of signals in a mobile communications network.

Such signals can be used, for example, for the transmission of data packets such as short messages.

Background to the Invention

In Germany, central Europe and many other parts of the world, the GSM standard has established itself as the leading mobile telecommunications standard and is accessible practically everywhere.

Packet transmission services have continuously gained importance in mobile communications. Such services include e.g. the SMS (Short Message Service), first introduced in the GSM (Global System for Mobile Communications) standard, and TCP/IP services. More details of these services are described in the book by M. -B. Pautet: The GSM system for mobile communications, published by the authors, ISBN 2-9507190-0-7, 1992, and in M. Rahnema: Overview of the GSM system and protocol architecture. IEEE Communications Magazine, vol. 31 (April 1992) no. 4, pp. 92-100.

In mobile communications, one example of a packet transmission service which has had tremendous economic success is the SMS used in GSM and in GPRS (General Packet Radio Service) mobile communications networks. Principles of the SMS are described in G. Brasche, B. Walke : Concepts, services, and protocols of the new GSM phase 2+ general packet radio service. IEEE Communications Magazine, vol. 35 (August 1997) no. 8, pp. 94-104. The SMS only allows a maximum of 160 characters to be transmitted.

In addition to the voice/data channels in the mobile communications systems used to transmit data and voice, control channels are used to construct the connection. The protocol used in communications technology is the SS7 (signaling system 7) protocol. In the GSM system this is supplemented by the MAP (Mobile Application Part) protocol. SMS services are transmitted over the signaling channel. The SMS services comprise a plurality of data signal. The signaling channel is also used for other types of signals.

As is pointed out in J. -H. Park: Wireless internet access for mobile subscribers based on the GPRS/UMTS network. IEEE Communications Magazine, vol. 40 (April 2002) no. 4, pp. 38-49, a sustained high Quality of Service (QoS) level is mandatory and insisted upon by the senders of the messages. In order to enable the deployment of the packet transmission services like SMS in professional environments, it is necessary to define and maintain a pre-determfned level of reliability for the packet transmission services and also to define and maintain attributes relating to precedence of packet transmission services as well as for the delay of the packet transmission service.

As pointed out above an SMS is constructed from a plurality of signals. Currently a sustantined high QoS level cannot be guaranteed for SMS transmission as the underlying plurality of signals do not have a defined QoS level. SMS Centers therefore cannot currently provide the high service quality in all cases. Among other reasons, this is because of packet losses of the signal due to, e.g. inadequate received signal quality, which is caused by the time and frequency selectivity of the mobile radio channel and by imperfections of mobile terminals. The packet losses are also produced by time-outs, entailing forced packet deletions. These forced packet deletions are the consequences of protocols In the signaling domain of the infrastructure of a mobile communications network, including the Base Station System Application Part + (BSSAP+) and the Mobile Application Part (MAP) protocols (this is discussed in J. -H. Park.¹ Wireless internet access for mobile subscribers based on the GPRS/UMTS network. IEEE Communications Magazine, vol. 40 (April 2002) no. 4, pp. 38-49).

The time-outs occur for various reasons. For instance, when a mobile terminal (such as a handset or a data card) which should be contacted by means of the SMS, stays outside the coverage area or has been switched off for a certain period of time, the allocated Mobile Switching Center (MSC) will detect an absent subscriber. Another cause for failure in the delivery of the packets occurs when an origin terminal or element (i.e. the point of origin of the packet) and a destination terminal (such as the mobile station) are subscribed to different network operators and the different network operators do not have roaming agreements between them.

When the SMS is used for non-professional, i.e. private, communication from one subscriber to another subscriber, the lack of sustained high QoS levels may be acceptable. However, this is no longer the case for the deployment of SMS in professional scenarios. Professional SMS communication is carried out in the following manner. In a first step an interface is provided to an SMS centre, (a so-called API). In the next step a request to send an SMS is accepted by the SMS centre connecting to the communications network and is then sent to the destination mobile terminal. After sending, some SMS centers report successful transmission. In the event that the SMS can not be sent, due to the above described reasons, some SMS centers store the message and perform further sending attempts, until, for example, no time-outs occur and the message is sent. The delivery attempts are scheduled in pre-configured time intervals. Further delivery attempts might be triggered by information from other elements of the communication network.

The checks in this system are, however, not adequate to ensure reliable, fast and accurate delivery of the message. There no guarantee that a message is delivered within a particular time period. Not all SMS centers provide reports in the event that a message is lost or notifications of receipt. It would be furthermore useful to be able to prioritise the delivery of the messages. Finally it would be useful from a business point of view to be able to adopt different pricing structures based on the dependency of reliability and service levels.

In order to reduce the effect of packet losses and, hence, to improve the quality of the packet transmission service, a quantitative analysis of the QoS in the signaling domain can be carried out. To date, only a few QoS parameters have been defined by the standards bodies. These QoS parameters operate only at the level of the SMS protocol and not in the signaling domain. The existing QoS parameters monitor the transmission quality only and cover only mobile-originated and mobile-terminated SMS. The definitions of the QoS parameters are tailored for the end-to-end transmissions and include delivery time and completion rate as QoS parameters. The definitions are given in ETSI: Digital cellular telecommunications system (Phase 2); Mobile Application Part (MAP) specification (GSM 09.02 version 4.19.1) ETS 300 599 December 2000, and in EETSI: Speech processing transmission and quality aspects (STQ); QoS aspects for popular services In GSM and 3G networks; Part 2: Definition of quality of service parameters and their computation. ETSI TS 102 250-2 Vl.2.1 (2004-06), June 2004.

Both A. Andreadis, G. Benelli, G. Giambene, B. Marzucchi. A performance evaluation approach for GSM-based information services. IEEE Transactions on Vehicular Technology, vol. 52 (2003) no. 2, pp. 313-325, and T.C. Wong, J. W. Mark, K.-C. Chua: Joint connection level, packet level, and link layer resource allocation for variable bit rate multlclass services in cellular DS-CDMA networks with QoS constraints. IEEE Journal on Selected Areas in Communications, vol. 21 (2003) no. 10, pp. 1536-1545, discuss the QoS parameters in their respective publications. The authors statistically model the packet traffic and present results on the related efficiency parameters.

5 To date the forced packet deletions mentioned above have not been taken into consideration. Furthermore, the existing QoS parameters (see the ETSI publications discussed above) do not completely fulfill the needs arising from a professional SMS.

Summary of the Invention iθ

It is therefore an object of the invention to provide QoS parameters.

It is a further object of the invention to provide QoS parameters for ensuring the delivery of data packets. 15

It Is yet a further object of the Invention to provide QoS parameters to limit the unwanted deletion of data packets and to minimize the impact of such unwanted deletions of data packets.

0 It is yet a further object of the invention to provide QoS parameters suitable for the monitoring of data packets in a communications network.

It is yet a further object of the invention to provide QoS parameters suitable for the monitoring of data packets in communications networks connected via roaming. 5

These and other objects of the invention are solved by providing a method and apparatus for monitoring the quality of data packet transmissions at the data packet transmission centre using various parameters in the signaling domain.

0 Unlike existing methods, the monitoring of the quality of data packet transmissions occurs at the data packet transmission centre from where the data packets are sent (e.g. from a SMS centre). The quality of the data transmission is produced in the form of a QoS parameter. There is no need to know the exact time or other parameters related to the receipt of the message at a mobile station. 5

Use of the method and apparatus allow the reconfiguration of the data packet transmission centre (e.g. the SMS centre) to be carried out automatically if the value of the QoS parameter reaches a certain threshold value. The threshold value is set to a value appropriate to the needs of the customer wishing to send the data packets, the 0 network operator instructed to transmit the data packets or parameters to optimize the completion rate of all SMS to be sent. It should be noted that depending on the type of QoS parameter the value of the QoS parameter may either exceed or fall below that of the threshold value.

The method and apparatus have been used in the sending of short messages (SMS) as data packets in a GSM system. It is envisaged that this invention will be of benefit in other protocols or for other types of data packets in mobile communications networks and nothing in this description is intended to limit this.

Description of the Figures

Fig. 1 shows a basic overview of a public land mobile network.

Fig. 2 shows the SMS transmission procedure assuming successful SMS delivery from the

SMS Center. Fig. 3 shows the system for QoS monitoring.

Fig. 4 shows the average delivery time per day.

Fig. 5 shows the typical completion rate averaged over one month.

Fig. 6 shows the Success Ration SR SMS and Error Ration E#R SMS.

Fig. 7 shows the relative number of error entries per day for one business partner Fig. 8 shows the Success Ration SR and Error Ration ER for one business partner per day

Rg. 9 shows the Success Ration and Error Ration for another business partner.

Detailed Description of the Invention

Fig. 1 shows the basic configuration of a public land mobile network 10. Mobile switching centres (MSC) 20, a visited location register (VLR) 30, a home location register (HLR) 40 and a Gateway MSC 70 are connected over a network 50. The network 50 is a SS#7 network in one embodiment of the invention with ports 60a-60f - so called signalling ports (SP) - to which the mobile switching centres 20, the visited location register 30, the home location register 40 and the gateway MSC 70 are connected.

The gateway MSC 70 is connected to a fixed line network 80 such as a public switched telephone network (PSTN) or a private network. Connection between other operators' networks is provided through the fixed line network 80. The mobile switching centre 70 is connected to a base switching centre (BSC) 90 which is in turn connected to a base transceiver station (BTS) 100. One or more mobile stations 110 are in contact with the base transceiver station 100.

The home location register 40 and the visited location register 30 are databases which store details about the mobile stations 110 connected to the network 10 and other data. All transactions between the home location register 40 and the visited location register 30, such as searches or updates are handled using the so-called Mobile Application Part (MAP) over the network 50. Similarly when the mobile station 110 moves from one cell served by a first base transceiver station 100 to another cell served by a second one of the base transceiver station 100, the handover is handled over the network 50. The functions of the mobile application part also include, but are not limited to, transactions related to the updating and deletion of location information in the visited location register 30 and the updating of user profiles in the home location register 40.

Fig. 1 also shows an SMS messaging centre 55 connected to the network 50. The SMS messaging centre sends data packets - representing the short messages - to the network 50 which are received at the mobile stations 110.

Although this invention has been described with respect to the existing GSM network, it is envisaged that this invention will work on all types of wireless networks such as CDMA, TDMA, 3G and WIFI networks which support the transmission of data packets.

Fig. 2 shows a time diagram for the successful transmission of a packet, containing in this example a short message, from the SMS Center 55 to the mobile station 110. It is not intended that this invention be limited to data packets containing short messages. It can be used In all services in a mobile communications network in which a signaling protocol returns success or error messages. Several commands and processes are used as described in Fig. 2.

From the point of view of the SMS Center 55 only three commands out of the MAP of the SS7 protocol are used, namely:

1) MAP-SEND-ROUTING-INFO-FOR-SM (srism)

This command is used between the gateway MSC (GMSC) 70 and the HLR 40 to retrieve the routing information needed for routing the data packet (short message) to the MSC 20 servicing the area in which the subscriber is currently roaming. The request for routing information sent to the gateway MSC 70 contains the MSISDN (Mobile Subscriber ISDN) of the subscriber. The result of the request returned from the gateway MSC 70 contains the ISDN number (routing address) of the servicing MSC 20. The routing address is used to forward the data packet (short message) in a forward SM process.

2) MAP-FORWARD-SHORT-MESSAGE (fwsm)

This command is used to forward mobile originated or mobile terminated data packets (short messages) between the Gateway MSC 70, which has a connection to the SMS Center 55, and the servicing MSC 20 servicing the area in which the subscriber is roaming.

3) MAP-REPORT-SM-DELIVERY-STATUS (rsds)

This command is used between the gateway MSC 70 and the HLR 40. When the transmission of the data packet (short message) from the SMS Center 55 to the mobile station 110 is unsuccessful, e.g. because the subscriber was absent, the servicing MSC 20 returns a negative response to the SMS Centre 55 and the SMS Centre 55 sends a ReportSM-DeliveryStatus parameter to the HLR 40 to allow for a delayed delivery of the short message. MAP-REPORT-SM-DELIVERY-STATUS is used to set a Message Waiting Data flag into the HLR 40 or to inform the HLR 40 of successful short message transfer after polling.

Every one of the commands delivers a status report. The interpretation of these status reports at the SMS Center 55 facilitates the generation of various error codes, including the acknowledgement of the successful delivery of the data packet or short message. The mapping of error codes to their verbal description has not been standardized. Table 1 shows a conceivable mapping of error code numbers to verbal descriptions as they are used in one embodiment of the invention. Since the error code descriptions are not standardized, yet, other error codes descriptions are conceivable.

Table 1

Error code Description

~0 ^■ Successful SMS Without Errors

78 TC-INVOKE Timeout

91 Unknown MSISDN

94 Absent Subscriber Short Message

102 Short Message Delivery Failure:

SIM (Subscriber Identity Module)/Mobile Terminal

Memory Exceeded

Supplementary services, such as location queries, requesting the address of the Servicing MSC 20 , or presence queries, requesting the availability of a particular mobile station 110 from e.g. the Servicing MSC 20 or the HLR 40 of the Gateway MSC 70, are also based on the use of the MAP commands for the data packets (short messages). For instance, the MAP-SEND-ROUTING-INFO-FOR-SM command already provides information about the location of a mobile station 110. This information can be analyzed to provide the desired information. In the embodiment of the invention, different service providers use the SMS Center 55 to transmit the data packets, for example In the form of short messages, of their customers. They are termed "Business Partner" to distinguish them from their customers, which normally the senders and receivers of the SMS.

The characteristics of the SMS traffic specific for each of the business partners. For instance, several ones of the business partners only offer SMS traffic related to individual users, termed individual SMS traffic, whereas other business partners send bulk SMS to their individual customers, termed bulk SMS traffic. The bulk SMS traffic is more difficult to handle than the individual SMS traffic because the chance of congestion is greater due to the large number of short messages in the form of data packets which have to be handled by the SMS Center 55 almost simultaneously.

The fwsm command Is used to deliver a particular short message to a customer, i.e. the owner of a SIM inside a mobile station 110, via its Servicing MSC 20. In order to locate the mentioned customer, the ISDN number of the Servicing MSC 20 must be determined. This ISDN number is considered as the routing address which is obtained by evaluating the report associated with a srism command.

As discussed in the introduction, there are several existing QoS parameters for monitoring the delivery of a short message. These are

1) Service Accessibility SMS MO,

2) Access Delay SMS MO, 3) End-to-end Delivery Time SMS and

4) Completion Rate SMS Circuit Switched.

(See EETSI: Speech processing transmission and quality aspects (STQ); QoS aspects for popular services in GSM and 3G networks; Part 2: Definition of quality of service parameters and their computation. ETSI TS 102 250-2 Vl.2.1 (2004-06), June 2004

The first two of the above QoS parameters, i.e. Service Accessibility SMS MO and Access Delay SMS MO, are not applicable to QoS evaluation in an SMS Center because they are tailored to the mobile originated short messages (i.e. short messages generated from a mobile station 110).

These existing QoS parameters are supplement in accordance with this invention by three additional QoS parameters. The additional QoS parameters are termed:

• Success Ratio SMS (SR SMS), i.e. the ratio of the number of MAP commands associated with error code 0 (see table 1) and the total number of MAP commands,

• Error # Ratios SMS (E#R SMS), i.e. the ratio of the number of a specific error code number # of the SS7 protocol (see table 1) and the total number of MAP commands,

and

• Effort SMS (E SMS), i.e. the average number of protocol commands to transmit a short message.

Although the above QoS parameters relate to the transmission of short messages SMS, they can be generalized to the transmission of any type of signals over the network 50.

In this case the first two QoS parameters would be termed Success Ratio Signals (SR

Signals) and Error # Ratios Signals (E#R Signals).

The SMS Centers 55 communicate with the service providers' infrastructures by using the

SS7 (Signaling System 7) protocol and therefore the additional QoS parameters consider the signaling domain explicitly.

The additional QoS parameters have been applied to the measurement of short messages and signals in real GSM networks. To quantify the corresponding QoS levels, the signals and error acknowledgements, made available through the SS7 protocol, have been evaluated. These signals and error acknowledgements also cover SMS related services, which use signals from the MAP of the SS7 protocol.

The additional QoS commands are derived as follows.

Suppose that t_reCei_ve denotes the point of time at which the mobile station 110 receives the short message from another mobile station or other item of mobile equipment and that t_seπdSMs is the point of time that the customer sends the short message to the SMS Center 55 from the other mobile station, the End-to-End Delivery Time SMS is defined as:

teπd-end-Deiive»γ_τim-_SMs ⁼ t_receive " t_sendsMS Equation ( 1)

See ETSI: Speech processing transmission and quality aspects (STQ); QoS aspects for popular services in GSM and 3G networks; Part 2: Definition of quality of service parameters and their computation. ETSI TS 102 250-2 Vl.2.1 (2004-06), June 2004 Both points of time, t_sendS_Ms and t_reCeι_Ve_/ are unknown at the SMS Center. This equation is modified as follows. The parameter t_reCeive is replaced by t_fws_m (the point of time associated with a successful fwsm command for a particular short message). The parameter tsendSMs is replace with the parameter t_srism (the point of time of the first srism command associated with the same short message).

The QoS parameter Delivery Time SMS (DT SMS) is the defined as follows:

TDT_SMS ⁼ tfwsm " tsrism Equation (2)

A further QoS parameter Completion rate SMS Circuit Switched is defined as follows:

Nsuc denotes the number of successfully received short messages, with N_DUP being the number of duplicate received short messages, N_C0R denoting the number of corrupted short messages and N_aι being the total number of sent short messages. The QoS parameter Completion Rate SMS Circuit Switched is defined according to ETSI: Speech processing transmission and quality aspects (STQ); QoS aspects for popular services in GSM and 3G networks; Part 2: Definition of quality of service parameters and their computation. ETSI TS 102 250-2 Vl.2.1 (2004-06), June 2004

CR SMS cS- ^{Nsϋc ~~ N}™ ^{~ N∞Λ} .Equation (3)

ΝeitherN_DUp nor N_C0R can be obtained at the SMS Center 55. Furthermore, the

parameter -^suc is unknown since the end-to-end reporting is not available to the SMS

Center 55. The QoS parameter Completion Rate SMS Circuit Switched is modified as follows:

Equation (3) is modified such that Λ^r _ftvsm__suc is the number of successful fwsm commands

and with -Wftvsm._ALL is the total number of all fwsm commands, having mutually different message IDs. The QoS parameter Completion Rate SMS (CR SMS) is defined in the following way:

_ -W fvwπvSUC

77CR SMs -— . Equation (4)

^' fivsm.ALL Measurement results for the new QoS parameters DT SMS ^DT SMS ^and CR SMS

V*CR SMS are presented later.

To improve the QoS level and to simplify the measuring process of the QoS parameters, the error codes of table 1 resulting from the interpretation of status reports are analyzed. The number of the error codes can be measured and the ratio to the total number of error codes can be calculated. The QoS parameters are SR SMS and E#R SMS.

Suppose that -/^MAP-SUC ^|S the number of successful MAP commands and ^MAP-ALL '^S the number of all MAP commands, the SR SMS is defined as

_n — N MAP-SUC

VSR SMS _λr . Equation (5) ^iV MAP-ALL

^MAP-ERRORØ '^{s tne} number of MAP commands having error codes which are non-zero. The QoS parameter E#R SMS is defined as

. Equation (6)

The further QoS parameter is E SMS. Under ideal circumstances, only two MAP commands are needed for a successful delivery of a new short message: First a srism command is sent which is followed by an fwsm command. When an error code other than 0 occurs (see table 1), more MAP commands are required for the delivery of the short message. It should be noted that in the case of concatenated short message packets (i.e. a plurality of short message packets sent back-to-back), only one command per packet is minimally required for those packets succeeding the first packet.

^Let PSEQ be the probability of a particular sequence of MAP commands and -^sL denote the number of MAP commands in the particular sequence, the QoS parameter E SMS is defined as

■ ^{E ==} Σ ^N"_SBQ ^' #%E_O Equation (7)

Thus, E is the average number of MAP commands needed to transmit the short messages.

It is worth mentioning that the measurement of the new additional QoS parameters can be done under special conditions, e.g. for selected business partners and for pre-selected special time intervals. Measurement results for the new additional QoS parameters are presented later.

Fig. 3 shows an overview of a QoS monitoring system 300 for QoS monitoring, alerting and reconfiguring the SMS Center 305. The SMS Center 305 stores all the commands on an SS7 interface and their status reports in an SS7 log database 310. The SS7 log database 305 is the information source for the QoS monitoring system 300. The QoS monitoring system 300 is connected to the SMS Center 305 via a virtual private network 315. The QoS monitoring system 300 further contains Java programs and a graphical analysis tool 320 to visualize the behaviour of different QoS parameters. The QoS parameters vary and depend on, for example, the traffic characteristics, the business partners or the Servicing MSC.

Desired value ranges for the values of the various QoS parameters are set in a Parameter Supervision block 325. These are chosen, for example, to depend on the traffic, which is expected from the various business partners, or on the error behaviour of the Servicing MSC. The values of the QoS parameters are then measured and compared to the desired value ranges stored in the Parameter Supervision block 325. Should the value of one of the QoS parameters be out of range, an alerting message 330 is sent to the operators of the SMS Center 305.

Should an adaptation of the system framework at the SMS center 305 lead to an improvement of the QoS level, an automatic reconfiguration can be initiated from a reconfiguration block. This automatic reconfiguration could be, but is not limited to, a modification of the scheduling of the retry cycles In the short message transmission system.

The parameter ^DT SMS defined in Equation (2) depends on the rate of the successfully

delivered short messages. Fig. 4 shows the SMS Delivery Time ^DT SMS with different

Completion Rates ^CR SMS as a parameter. Most of the short messages are successfully delivered within a few seconds. Due to high traffic there are peaks for the completion rate

^DT SMS ^{of U}P ^{t0 80% on} some days. The completion rate ^DT SMS on the other hand depends on the time interval, which is allowed for the delivery of the short messages. Fig. 5 shows the completion rate for the time interval between 0 and 15 seconds. Higher values than 70% are hard to reach because of many destination mobile stations 110 that are not reachable, because they switched off their mobile, are outside of the coverage area or do not have valid contracts to service providers anymore.

Fig. 6 shows the Success Ratio %R SMS ^and several Error Ratios ^E_{#R S}MS ^for three business partners of the SMS Center. For business partner A the E94R SMS 77E<MR SMS _/ representing "Absent Subscriber" (see Table 1 - Error 94 is "Absent Subscriber", has nearly the same value as the Success Ratio ^SR SMS - ^Tne traffic caused by business partner A was directed to many mobile stations 110, which were not available at the time the short messages were sent. On the other hand, business partner C caused traffic, which had a large Success Ratio ^SR SMS ^{and a ver}Y '^ovv E94R SMS ?7E94R SMS • The values corresponding to business partner B are in between the values of the business partners A and C.

The relative number of several error entries per day for business partner A can be seen in

Fig. 7. Large values of entries with error code 0 (Table 1) and large values of entries with error code 94 are respectively concentrated on two days and three days. The corresponding Success Ratio ^_SR SMS ^{and tne Error Ra}tios E94R SMS ^94R SMS and E78R SMS η_mΛSMS can be seen in Fig. 8 as a function of time (day). The E94R SMS reaches large values of over 70% on three days. If these values of the QoS parameters ?7E#R SMS ^are detected, a reconfiguration of the transmission system at the SMS Center 305, e.g. a change in the scheduling of the retry cycles can reduce the number of MAP commands with the outcome of error code 94. Fig.9 on the other hand shows the Success Ratio ^SR SMS ^and two Error Ratios E#R SMS 77_£#_{R SM}s f°^r business partner C. The Success Ratio ?7SR SMS is larger than 80% nearly over the whole time interval. The Error Ratio E94R SMS 7E94R SMS ^Ratio is at about 10%, other Error Ratios are negligible. The values for business partner B are in between the values of the business partners A and C.

!0

TABLE 2 PROBABlLmES FOR SEQUENCES OF SIGNALS

Sequence

Probability s: srism, f:

r. rsds Length 0, 78, 91.94 etc: Error Codes

63,21% 2 sOfO

8.«% sO

7,30% s 78

1.92% s91

1,31% s 94

1,23% fO

0,83% 6 S0f94r0r0s0f0

0,77% 7 s 0 f 94 r 0 r 0 s 94 s 0 f 0

0.53% 4 Sθf87s0f0

0,51% 8 Sθf94r0r0s94s94s0f0

0,43% 4 sθf78sθfθ

0,41% 9 s 0 f94 r 0 r 0 s 94 s 94 s 94 s 0 f

0,35% 5 s94rθrθsθfθ

0,30% 10 s 94 r 0 r 0 s 94 s 94 s 94 S 94 s 94 r

0,25% 4 s94s94sθfθ

0,25% 2 sθf98

0,24% 6 s 78 s 78 s 78 s 78 s 78 s 78

0,23% 6 S94r0r0s94s0f0

Table 2 shows the most probable sequences of MAP commands averaged over one month 5 in 2004. The sequences in Table 2 represent 88% of all messages and 59% of all signals in that month. The calculation of the Effort E SMS defined in Equation (7) for the said month leads to a value of the Effort E of 3. If the Effort E increases, the reconfiguration can change the retry schedule at the SMS Center in order to reduce the number of MAP commands which are needed to transmit the short messages. This reduces efforts and 0 cost at the SMS Center.

The method and apparatus of the invention can be used to enable the following applications: i) the stock broker who wishes to receive market data accurately and reliably 5 within a given period of time; ii) news agencies who are sending sensitive data direct to financial analysts iii) a patient who needs to receive the address of the most appropriate hospital in the event that he or she falls; iv) suppliers of exclusive "fresh" products who need to monitor the temperature of a container and - if necessary - document it for the client. In the event of a failure, the cooling container needs to be replaced; v) the logistics company which needs to be able to ascertain the locations of freight cars, lorries, containers, etc.

The foregoing is considered illustrative of the principles of the invention and since numerous modifications will occur to those skilled in the art, it is not intended to limit the Invention to the exact construction and operation described. All suitable modifications and equivalents fall within the scope of the claims-

is

Claims

1. Method for the monitoring of the quality of signal transmission in a communications network having a signal transmission centre for the transmission of signals and at least one recipient, wherein at least one of the sender and/or the recipient are connected to a mobile communications network, the method comprising:

- a first step of monitoring a first parameter at the signal transmission centre;

- a second step of monitoring a second parameter at the signal transmission centre; and

- a third step of calculating a quality of service parameter from the first parameter and the second parameter.

2. The method of claim 1, wherein the first step comprises the step measuring the time at which the signal is transmitted from the signal transmission centre.

3. The method of claim 1 or 2, wherein the second step comprises the step of measuring the time at which the routing information or other result data for the signal is obtained.

4. The method of claim 1, wherein the first step comprises recording the total number of commands associated with transmitting the signal to the at least one recipient.

5. The method of claim 1 or 4, wherein the second step comprises recording the total number of commands required to successfully transmit the signals from the signal transmission centre.

6. The method of claim 1 or 4, wherein the second step comprises recording the total number of errors associated with the commands for transmitting the signal to the at least one recipient.

7. The method of any one of the above claims wherein the signal comprises a short message.

8. The method of any one of the above claims wherein the communications network is a GSM network or a UMTS network.

9. Apparatus for the monitoring of the quality of signal transmission in a communications network comprising: - a data signal transmission centre for receiving one or more signals and for transmitting the one or more signals to at least one network component:

- a first storage area for storing a first parameter;

- a second storage area for storing a second parameter; and - a processor for calculating a quality of service parameter from the first parameter and the second parameter.

10. The apparatus of claim 9, wherein the first parameter comprises the time of at which the one or more signals is transmitted from the signal transmission centre.

11. The apparatus of claim 9 or 10, wherein the second parameter comprises the time at which the routing information or other result data for the one or more signals is obtained.

12. The apparatus of claim 9, wherein the first parameter records the total number of commands associated with transmitting the one or more signals to the at least one recipient.

13. The apparatus of claim 9 or 12, wherein the second parameter comprises the total number of commands required to successfully transmit the one or more signals from the signal transmission centre.

14. The apparatus of claim 9 or 12, wherein the second parameter comprises the total number of errors associated with the commands for transmitting the one or more signals to the at least one recipient.

15. The apparatus of any one of claims 9 to 14, wherein the communications network is a GSM network or a UMTS network.

16. The apparatus of any one of claims 9 to 15, wherein the one or more signals form a short message.

17. The apparatus of any one of claims 9 to 16, wherein the at least one network component is a mobile station.

18. Method for the transmission of data packets from a data signal transmission centre comprising:

- a first step of monitoring the quality of the data packets using the method of at least one of claims 1 to 8 to produce at least one quality of service parameter; and - a step of reconfiguring the data signal transmission centre based on the quality of service parameter.

19. The method of claim 18 further comprising a message sender for transmitting a reconfiguration message in the event that the at least one quality of service parameter exceeds a threshold.

20. Apparatus for the transmission of data packets from a data signal transmission centre comprising: - a first monitoring unit for calculating at least one quality of service parameter; and

- a reconfiguring unit for reconfiguring the data signal transmission centre.

21. The apparatus of claim 20 further comprising a message sender for sending at least one reconfiguration message from the first monitoring unit to the reconfiguring unit.