GB2385490A

GB2385490A - Terminal and network monitoring and testing in mobile communications systems

Info

Publication number: GB2385490A
Application number: GB0203436A
Authority: GB
Inventors: David Martin Cooper
Original assignee: Hutchison Whampoa Three G IP Bahamas Ltd
Current assignee: Hutchison Whampoa Three G IP Bahamas Ltd
Priority date: 2002-02-13
Filing date: 2002-02-13
Publication date: 2003-08-20
Also published as: GB0203436D0

Abstract

A method of monitoring the performance of a mobile communications network and/or a terminal using the network in which signals are routed via the network between the terminal and a server, the method comprising analysing signals received by the server relating to the performance of the terminal or network whereby to monitor the operation of the network and/or terminal. System performance may be analysed using any number of the following parameters over time, possibly the duration of a data stream: received signal strength indicator, signal to noise ratio, ratio of energy per bit to noise, ratio of energy per chip to noise, block error rate, frame error rate for voice, measured data rate, location of terminal. System performance may be measured with respect to location. Sampling of the above parameters may be carried out and stored, possibly removably, in the terminal, and transmitted to the server upon a request from the server. Preferably, there is more than one sampling rate that is varied according to the mode of operation, either governed by the terminal or the server. The monitoring of performance may be carried out during a test sequence sent from the server upon request by the terminal, user, user contact centre, or upon abnormal operating conditions. An abrupt deterioration of a measured parameter may be interpreted as a fraud attempt.

Description

Terminal and network monitoring and testing in mobile communications systems The present invention relates to a radio transceiver or terminal for use in a mobile telecommunications system as well as a mobile telecommunications system utilising such a transceiver/terminal.

In its simplest form, a mobile telecommunications system includes radio terminals operated by users, a radio network, a core network and network servers whose purpose is to allocate routes to signals e. g. from one terminal to another. In the mobile communications systems currently in use in the United Kingdom, when terminals are switched on, they are able to transmit to the nearest base stations identification signals over a narrow frequency band simply to identify their whereabouts. When a call is established, a wider frequency band is allocated to the call to enable voice data to be exchanged between terminals, also known as terminals.

It is intended that the next mobile telecommunications network, known as the third generation or 3G network, will operate in an radically different manner in a number of respects. Such a network is already in operation in Japan. One significant difference is that in the 3G network, a terminal will have an always on packet based network connection sufficient to transmit broader band signals. As a result, the user will be able to communicate with any data networks such as data servers in the"home"network or on the Internet as well as users of other terminals. As a result, a wider range of data can be exchanged between the user and the network servers via this packet network connection with the possibility of a simultaneous voice call. The ability to transmit more complex services between user and servers heightens the potential for customer complaints and hence the need for increased reliability of the system as a whole and a remote diagnosis capability.

According to the present invention, information relating to the performance of a network and/or terminal is supplied to a network server for remote diagnosis.

In one aspect, the invention provides a method of monitoring the performance of a mobile communications network and/or a terminal using the network in which signals are routed via the network between the terminal and a server, the method comprising analysing signals received by the server relating to the performance of the terminal or the network whereby to monitor the operation of the network and/or terminal.

The signals relating to the performance of the terminal or the network will usually be provided by the terminal. A typical terminal will already have some of the necessary capability, such as the ability to measure received signal strength. However, this information is usually provided simply for the benefit of the user-e. g. to show a customer when calls are possible, and is not sent back to the server.

Thus, another aspect of the invention provides a terminal for use in this monitoring as described in claim 24.

Another aspect of the invention provides a server equipped to perform the remote monitoring of the network/terminal as desribed in claim 18.

Any number of the following parameters may be sampled: (a) received strength indicator (RSSI) (b) signal to interference ration (SIR) (c) energy per bit/noise (Eb/No) (d) energy per chip/noise (Eb/No) (e) block error rate for data (BLER) (f) frame error rate for voice (FER) (g) measured data rate (h) location of terminal All of these parameters are defined in 3G network standards.

In some applications of the invention, it is useful to monitor the variation of the parameters described above over time. Additionally or alternatively it is useful to monitor parameters (a) to (g) relative to location. This will give information relating to the network coverage.

The terminal forms part of an end-to-end solution which can be used to diagnose a wide range of issues with the more complex 3G services requested.

The memory means may be a removable device such as the USIM used in current mobile telephones or some other local storage means.

The terminal may be inactive from a sampling perspective for long periods of time. It could be activated remotely by server based applications or locally by terminal based applications. The rate of sampling data may be variable according to the mode of operation of the terminal and its capabilities, as will be explained in more detail below. The sample rate may be variable in response to a signal received over the network and/or the terminal may have means for initiating a change in the sample rate.

One example is when initiating certain types of activity a terminal application may change the sampling process parameters, such an example could be at the start of receiving a data stream. In this example the frequency of the sampling would be significantly increased. The terminal may be arranged to transmit to the server data stored in the memory means at predetermined intervals, when the memory is full, or at the end of an event (completion of a stream). Alternatively, such transmission may be initiated in response to a signal received over the network or when abnormal terminal conditions are detected.

Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which:

Fig. 1 is a block diagram showing the basic components of a typical radio terminal such as a mobile telephone; Fig. 2 illustrates a communications network; Fig. 3 is a schematic diagram showing the steps involved in carrying out a customer remote self test of a terminal ; Fig. 4 is a schematic diagram showing the steps involved in a contact centre test of a terminal ; and Fig. 5 is a schematic diagram showing how streaming fraud attempts might be detected in a scheme where the user pays for a streaming service and not based on packet counting; Fig. 6 is a schematic diagram of billing based on the measured customer experience; and Fig. 7 is a schematic diagram showing how network monitoring/measuring could be achieved.

Referring now to the drawings, Figure 1 is a very basic block diagram showing some of the components of a radio terminal. Radio frequency (RF) signals are received/transmitted via antenna 10 and converted to or from an intermediate frequency (IF) in frequency converter 12. Incoming signals are converted to digital in analogue to digital converter (A/D) 13 whilst outgoing signals are converted from digital to analogue in digital to analogue converter (D/A) 14. Digital signals are processed in digital front end 15 which has associated memory 16 the digital front end communicates with the visual display unit 20 and speaker/microphone 21.

The terminal may have the capability to measure any of the following parameters, typically within the digital front end: (a) received strength indicator (RSSI)-This shows the strength of the received signal and an indicator for this parameter is typically shown to the user interface to allow the customer to diagnose simple call problems (low network signal strength).

According to the present invention RSSI data may be conveyed to a network server.

(b) signal to interference ratio (SIR)-As many users in the network will be using the same frequency and a users signal is received using a code"key". All other traffic in the cell with the same frequency will be perceived as interference or noise.

(c) energy per bit/noise (Eb/No)-After the user's signal has been extracted from the incoming signal the resulting digital bit stream still contains some noise and this ratio shows that relationship. A higher Eb/No results in easier detection of the user data stream and a very low ratio will ultimately result in being unable to recover the original user data.

(d) energy per chip/noise (Eb/No)-WCDMA systems"encode"the data at a"chipping" rate that is higher than the data rate and it helps in the recovery of the signal. This is the energy within a chip compared to the noise. The higher this ratio the easier is the recovery of the user data.

(e) block error rate for data (BLER)-Data is arranged into blocks and this shows the error detected within those blocks (f) frame error rate for voice (FER)-Data is arranged into frames and this shows the error detected within those frames (g) location-this can be either via cell id, cell triangulation, assisted global positioning system etc (h) measured data rate-the data rate seen by the applications in the terminal The measurement of the parameters described above enables the terminal to operate in a number of different end to end solutions as described below.

Figure 2 illustrates a communications network by way of background. A terminal 50 is capable of measuring and feeding back to servers a range of parameters as described above. The terminal communicates with the UMTS radio access network via transmitters, one of which is indicated at 51. Voice data from the terminal might be routed via circuit switched network 52 to a PSTN server 53 whilst other data is routed via the packet switched network 54 to packet services servers indicated generally at 55

which, amongst other things, communicate with the terminal 50 for analysis and diagnosis of services.

Customer remote self test of terminal Figure 3 is a schematic diagram indicating how terminals might be tested according to the invention. Like parts in Figures 2 and 3 are given like numerals. Capital letters indicate process steps. Server network 55 may include more than one remote test server. The following description refers to one server indicated by reference 56 although more than one may be involved in practice. In fact, the various components of the server network 55 may be inter-connected via the radio network 51.

A terminal user experiencing problems is able to initiate a remote self test procedure from the terminal. Thus at step A the self test request signal is transmitted to the testing server 53.

The terminal is either already monitoring parameters at regular intervals or the server signals the terminal (Step B) to initiate monitoring. Following this initiation signal, the server then sends (Step C) either a predefined test sequence or generates a test sequence as required which may depend on the terminal type. A predefined test sequence may be used as it could reduce the processing load in the terminal. The terminal measures a number of parameters (as defined previously and depending on its capability) during the transmission of this test sequence phase and responds to the server (Step D). The server then analyses the data it received from the terminal. It responds to the terminal (Step E) with information such as analysis of test data, confirmation of success (i. e. no fault detected) or problems, and an instruction to contact a customer centre for service information or additional testing. This could be extended to automatically connect the customer to a contact centre who could deal with the customer problem.

It should be noted that the testing server is a novel part of the server network which will respond to terminal requests, initiate a test sequence, collect data from the terminal, analyse the data and produce output to the terminal.

Contact centre test of terminal Figure 4 is a schematic diagram illustrating how remote testing of a terminal might be initiated by a contact centre.

The communications system as a whole is the same as that shown in Figure 3 with an addition of a contact centre 60. In this proposed method, a customer experiencing problems interacts with a contact centre via either via a voice or data connection (Step A). The procedure outlined above is then followed except that it is the contact centre 60 which contacts the server 56 to initiate a test sequence (Step B). The server sends either a predefined test sequence or generates test sequence as required. (Step C). The terminal measures a number of parameters and responds to the server (Step D) the server reports the measured parameters and the analysis to the contact centre and the contact centre has the capability to further analyse the returned data and diagnose the problems. Examples of the problems that could be diagnosed are problems with the terminal, network coverage or interference. The contact centre can respond to the customer (Step E) with confirmation of success in solving the problem or report problems found and can take appropriate action or instruct the customer on what actions should be taken.

Detection of streaming failures or fraud attempts The 3G communications system will have the new capability to stream data to users. This involves the terminal receiving a continuous stream of data which is then processed in real time to produce an output for the user. Such data streams might comprise audio or video clips for example and the receipt will usually be paid for by customers. There are a number of ways in which charges could be levied for this

service but if the one used is based an a pay per view it is envisaged that customers might dispute payment for data streams if they are incomplete. A possible attempt at fraud on such a streaming service would be to disconnect the terminal battery just before the normal termination of a stream and then to allege that the stream was not completely received. According to the present invention, such a fraud attempt can be detected and dealt with. The procedure is illustrated schematically in Figure 5. In this figure the server network includes a streaming server 70 and fraud server 71. A customer will initiate a request for a streaming service (Step A), the server will respond (Step B) and may instruct the terminal to initiate or change its monitoring mode. The parameters will be come from the list defined earlier. Streaming information is then sent to the customer (Step C) with the terminal recording all parameters to local storage until the battery is disconnected. If the customer has disconnected the battery there will be an abnormal termination and the streaming server will have a record of this event. When the terminal is restarted the software in the terminal checks to see if it has significant stored information and either establishes a connection or waits until it is contacted by the server to download the stored information to a fraud server. For example, this might be in response to a customer asserting that an incomplete data stream has been received. The sending of this data is indicated by at Step D. If the stored data indicates that the received signal strength from the network was high (RSSI) and the signal to noise ratio of the data is also high (Eb/No) but there was an abnormal end to the stream deduced from the data from the streaming server, this is therefore an indication of possible fraud. Alternatively, if the RSSI is low and the Eb/No is also low and there is also an abnormal end to the service then it is likely that the customer departed from the area with good network coverage rather than deliberately ending the stream.

Charging based on received quality of service (OoS) Charges to customers are currently billed by time for circuit switched connections and by total number of packets sent for the packet connections. When packet data is

transmitted and is subject to errors during transmission the higher layers in the communications protocol stack, such as FTP, will retransmit the lost packets and the customer will also be charged for the resent packets. It is envisaged that charges rendered to customers might be tailored according to the quality of service received by those customers. To this end, a terminal might be configured to monitor a range of parameters over the charging period. It might be programmed to store data only when a set of predefined conditions have been broken so as to minimise the storage requirement, such as retransmission events etc. This is illustrated schematically in Fig.

6. The terminal would report these recorded parameters occasionally to a Service analysis server 81 (Step A) or when requested to download data. The server would process the data and in the case of problems the network operator could take appropriate action. Such action might include contact with the customer to test the handset, or the data could be passed to a billing server 82 (Step B) to modify a customer's bill in the light of poor customer experience.

Network measuring/monitoring via remote terminals Once equipped to measure the parameters described above, information from terminals will enable the whole of the network to be randomly monitored at little extra cost. For example, storage of parameters such as RSSI against terminal location will give an indication of the coverage of the network and highlight any"gaps"where signals cannot be received. Another example is where RSSI is high but Eb/No is low could indicate interference from adjacent cells both of these could enable improvements in future network design. Recording of the customer measured data rate along with the block error rate gives a good measure of the customer experience.

Figure 7 schematically illustrates network monitoring. The server network 55 includes network monitoring server. Some or all customers may have network monitoring software enabled within their terminals in which case they continue in their normal usage pattern. The server 90 periodically polls or the devices

periodically upload measured parameters. The data is then analysed according to a set of rules which will diagnose network problems and allow network optimisation.

Claims

1. A method of monitoring the performance of a mobile communications network and/or a terminal using the network in which signals are routed via the network between the terminal and a server, the method comprising analysing signals received by the server relating to the performance of the terminal or the network whereby to monitor the operation of the network and/or terminal.

2. A method as claimed in claim 1 including sampling any number of the following parameters: (a) received signal strength indicator, (b) signal to interference ratio, (c) ratio of energy per bit to noise, (d) ratio to energy per chip to noise, (e) block error rate, (f) frame error rate for voice, (g) measured data rate, (h) location of terminal.

3. A method as claimed in claim 2 including analysing the variation of any of the parameters over time.

4. A method as claimed in claim 3 carried out during the transmission of a data stream in which one or more of the parameters (a) to (g) is recorded as a function of time for the duration of the transmission of the stream whereby to monitor the quality of the stream.

5. The method of claim 4 in which an abrupt deterioration of a measured parameter is interpreted as a fraud attempt.

6. A method as claimed in claim 2 or 3 including analysing the variation of any of parameters (a) to (g) relative to location.

7. A method as claimed in claims 2 to 6 in which the sampling of parameters is carried out by means provided in the terminal.

8. A method as claimed in claim 7 in which the parameters are stored in the terminal.

9. A method as claimed in claim 7 or 8 in which the terminal is operable in two or more modes and the rate of sampling the data by the terminal is varied according to the operating mode of the terminal.

10. A method as claimed in claim 7,8 or 9 including varying the rate of sampling the data by the terminal in response to a signal sent from the server to the terminal.

11. A method as claimed in any preceding claim in which: a test sequence of data is transmitted from the server to the terminal, and the terminal responds to the server, whereby the server can analyse the performance of the terminal and/or the network.

12. A method as claimed in claim 11 in which the test sequence is generated by the server in response to a request signal from the terminal.

13. A method as claimed in claim 11 in which the test sequence is initiated by a user.

14. A method as claimed in claim 11 in which the test sequence is generated by the server in response to a signal from a user contact centre.

15. A method as claimed in claim 11 in which the test sequence is generated in response to abnormal operating conditions being detected by the terminal or the server.

16. A method as claimed in any preceding claim including causing the terminal to transmit performance data to the server at regular intervals.

17. A method as claimed in any preceding claim including causing the terminal to transmit performance data to the server in response to a signal from the server.

18. A radio network server which communicates with one or more terminals via the radio network, the server having means for receiving and analysing signals received from the terminal (s) relating to the performance of the network and/or the terminal (s) whereby to monitor the operation of the network and/or terminal.

19. A server as claimed in claim 18 having means for receiving and analysing any number of the following parameters: (a) received signal strength indicator, (b) signal to interference ratio, (c) ratio of energy per bit to noise, (d) ratio to energy per chip to noise, (e) block error rate, (f) frame error rate for voice, (g) measured data rate, (h) location of terminal.

20. A server as claimed in claim 19 having means for monitoring the variation of the parameters over time.

21. A server as claimed in claim 19 or 20 having means for monitoring the variation of any of parameters (a) to (g) relative to location.

22. A server as claimed in claim 18,19, 20 or 21 having means for sending a signal to a terminal to control the rate at which the terminal acquires performance data.

23. A server as claimed in any of claims 18 to 22 having means for controlling the sending of performance data by the terminal to the server.

24. A radio communication terminal for transmitting and/or receiving radio signals encoded with digital information over a radio network server and having a digital front end including signal processing means for encoding/decoding said information, said terminal further having means for sampling data relating to the performance of the terminal and/or the network, and means connected to the digital front end whereby sample data may be transmitted to the server.

25. A radio terminal as claimed in claim 24 in which the rate of sampling said data is variable according to the mode of operation of the terminal.

26. A radio terminal as claimed in claim 24 or 25 in which the sample rate is variable in response to a signal received over the network.

27. A radio terminal as claimed in claim 24,25 or 26 in which the terminal has means for initiating a change in the sample rate.

28. A radio terminal as claimed in any of claims 24 to 27 having means for sampling any number of the following parameters:

(a) received signal strength indicator, (b) signal to interference ratio, (c) ratio of energy per bit to noise, (d) ratio to energy per chip to noise, (e) block error rate, (f) frame error rate for voice, (g) measured data rate (h) location of terminal,

29. A terminal as claimed in claim 24 on which said means connected to the digital front end include memory means for storing sampled data.

30. A terminal as claimed in claims 28 and 29 in which the memory means stores information relating to the variation of the parameters over time.

31. A terminal as claimed in claims 28 and 29, or claim 30 in which the memory means stores information relating to the variation of any of parameters (a) to (g) relative to location.

32. A radio terminal as claimed in any of claims 24 to 31 arranged to transmit to the server data stored in said memory means at predetermined intervals.

33. A radio terminal as claimed in any of claims 24 to 32 arranged to transmit to a server data stored in said memory means in response to a signal received over the network.

34. A radio terminal as claimed in any of claims 24 to 33 in which said memory means is removable from the terminal