WO2001098791A1

WO2001098791A1 - Method for evaluating a communication link, terminal and system therefor

Info

Publication number: WO2001098791A1
Application number: PCT/FR2000/001759
Authority: WO
Inventors: José FONTAINE
Original assignee: Schlumberger Industries S.A.
Priority date: 2000-06-23
Filing date: 2000-06-23
Publication date: 2001-12-27
Also published as: EP1309873B1; AU2000259907A1; ATE371870T1; DE60036229D1; EP1309873A1; ES2292451T3; DE60036229T2

Abstract

The invention concerns a method for evaluating a communication link between a communication module (10) connected to a counter (12) and a remote reading terminal (14). The invention is characterised in that it consists in: setting up the communication link between the module (10) and the terminal (14) in specific operating conditions; in substantially similar operating conditions, acting in controlled manner on at least one of the communication parameters of the terminal (14) and detecting whether the communication link between the module (10) and the terminal (14) is set up.

Description

METHOD FOR EVALUATING A COMMUNICATION LINK. TERMINAL AND SYSTEM FOR IMPLEMENTING SUCH A TEL

PROCESS

The present invention relates to a method for evaluating a communication link between a transmitter or a first transmitter / receiver and a receiver or a second remote transmitter / receiver. It also relates to a terminal for implementing the method and to a system comprising such a terminal. It applies in particular to the field of remote meter reading, which can be water, gas, electricity or heat meters.

These meters must be read regularly to read the quantity measured, in particular for billing purposes. Usually, a technician takes over by going to the same place of installation of the meter. However, it is sometimes difficult to have access to the meter, for example when the latter is installed in a private home when the technician is away. In addition, visiting each individual with a counter slows down the relief operation.

This is why remote meter reading systems have been developed allowing an operator moving within a certain geographical area to read the meters located in this area remotely. According to another type of configuration, the meters communicate with a fixed receiver in the area considered.

The main types of communication used are radiofrequency or wired communications (cable network). Each counter in a zone is then fitted with a transmitter or a transmitter / receiver, often called a communication module, capable of communicating with a receiver or a transmitter / receiver, often called a terminal or concentrator, which can be fixed or mobile in the area under consideration. Either in response to an interrogation signal sent by the terminal, or substantially periodically, the communication module transmits the information to be transmitted concerning the counter to which it is connected. The terminal receives this information which is then processed, for example for statistical or billing purposes.

As a rule, the communication link is tested during installation. However, these tests can only be carried out by experienced technicians because they use sophisticated devices different from those subsequently used in remote reading operations.

In addition, if the link budget is sufficient during the tests, there is nothing to confirm that the latter will not deteriorate as a function of the aging of the electronic components, changes in climatic conditions or the environment of the meter, or other. For example, it is known that radio frequency transmitters have performances which vary as a function of temperature. A connection tested in summer and found sufficient may not be established in winter. Or, the operation of a communication module can be disrupted if the environment is changed: moving a household appliance near a counter located for example in a kitchen can blur the connection.

It is therefore desirable to be able to quantify the quality of the communication link for each communication module. In the case where the operating margin is sufficient, it can be predicted that the communication link will be sufficient despite the appearance of disturbances such as the aging of the electronic components, change in temperature or environment, or the like.

However, it is also desirable to carry out this measurement without having to go to each communication module and without implementing sophisticated and expensive measurement equipment. The present invention achieves these objectives. More specifically, it relates to a method for evaluating a communication link between a communication module connected to a meter and a remote reading terminal and consisting in:

^» Establish the link between module and terminal under given operational conditions,

• Under substantially the same operational conditions, act in a controlled manner on at least one of the communication parameters of the terminal and detect if the communication link between module and terminal is established.

The communication parameters of the remote reading terminal consist essentially of the reception sensitivity and the transmission power if the terminal includes a transmitter.

The operational conditions are those at the time of the establishment of the communication link. These conditions are not necessarily known at the time of the evaluation. For example, the real effect of the aging of the electronic components of the communication module is poorly determined. But what is important is that these conditions do not vary significantly during the assessment stages.

A decisive advantage of the method according to the invention consists in testing the connection from the terminal alone, without it being necessary to go to the communication module, to simulate it or to manipulate it. The test is carried out with the devices usually used to carry out remote reading communications and in an extremely simple and rapid manner.

In accordance with the method according to the invention, it can be estimated whether the communication link continues to be established under degraded communication conditions and what are the operating limits. From this information, it can be predicted whether the communication link can be established despite variations in operational conditions. In accordance with a particular operating mode of the method according to the invention, the link is degraded by controlled action on at least one of the communication parameters of the terminal until the link is broken. The action can be continuous or performed in increments. Knowing the values of the communication parameter or parameters when the link is established under the initial conditions and when it is broken makes it possible to deduce an operating margin expressed in dB. This operating margin somehow reflects the capacity of the link to undergo disturbances.

Depending on the operating margin measured, it can be ensured, for example, that the connection will be established satisfactorily despite the usual temperature variations, the other operational conditions remaining substantially constant.

Usually, it is estimated that variations in operational conditions, all disturbances combined, correspond to an attenuation of an operating parameter with a minimum value of approximately 6 dB. This is why according to another operating mode of the method, the value of at least one communication parameter is attenuated by a fixed number of decibels, for example 6 dB, corresponding to a disturbance in the communication link representative of the usual disturbances. that can undergo said bond over time.

According to a variant, the controlled action consists in attenuating the transmission power of the remote reading terminal.

According to another variant, the controlled action consists in attenuating the sensitivity on reception of the remote reading terminal.

According to another variant, the controlled action consists in simultaneously attenuating the transmission power of the remote reading terminal and its sensitivity on reception. Depending on the variant chosen, the link is tested during the transmission phase by the terminal alone, reception by the terminal or both. The present invention also relates to a remote reading terminal for implementing the method. This terminal notably includes an antenna connected to reception or transmission / reception means. It further comprises an attenuator capable of attenuating in a controlled manner the reception sensitivity of the terminal, or the transmission power or both.

Again, note the extreme simplicity of the device which allows the use of the remote reading equipment itself for testing purposes. It also has the advantage of being able to be used by the remote reading operator without the need to call in a specialized technician or sophisticated and expensive equipment.

Advantageously, the attenuator is programmable. In this case, the operator can choose the desired operating mode: either apply a given attenuation, the value of which can possibly be set by the operator, or progressively attenuate at least one of the communication parameters within a given attenuation range up to '' that eventually the connection is broken.

The present invention finally relates to a remote reading system for implementing the method and further comprising at least one communication module connected to a meter, and at least one remote reading terminal according to the invention.

The description which follows, given by way of nonlimiting illustration, refers to the appended drawings in which:

"Figure 1 shows schematically a remote meter reading system over the air;" Figure 2 schematically shows a remote meter reading terminal according to the invention.

As can be seen in FIG. 1, a meter reading system comprises communication modules 10, each of these modules being connected to a counter 12. The communication module can also be integrated into the counter. The communication module receives the counting information from the counter as well as certain other information such as, the identification of a geographical area, a number assigned to the counter, an indication of fraud, etc.

This information is intended to be transmitted to a remote metering terminal 14. In the example described and shown, the communication is carried out by a radiofrequency link but this link could be carried out via a wired network, this in an equivalent manner from the point of view of the invention.

In remote reading systems, the link between module 10 and terminal 14 can be of the one-way, one-and-a-half and two-way type. In the first case, each module 10 periodically transmits the information to be transmitted; the module 10 only comprises transmission means while the terminal comprises only reception means. In the second case, each module

10 transmits the information only after having received an awakening signal sent by the terminal 14; the module 10 then comprises reception means in addition to the transmission means and the terminal 14 comprises transmission and reception means. In the latter case, the module 10 and the terminal 14 are capable of interacting with each other and each comprise means of transmission and reception.

The remote reading terminal 14 can be fixed or mobile. In the latter case, it can be loaded into a vehicle moving in the survey area or carried by an operator.

The terminal 14 shown diagrammatically in FIG. 1 is of the portable type.

11 includes a display 16 and push buttons 18 allowing various commands.

This terminal 14 is also shown more precisely although in a schematic and simplified manner in FIG. 2. It can be seen that it comprises an antenna 20 connected to an input / output of an attenuator 22. The latter is connected at output to an input reception means 24. The reception means 24 usually comprise a specific circuit with direct conversion without intermediate frequency comprising a local oscillator or a frequency lowering circuit connected to a local oscillator and connected to a demodulator. They are well known to those skilled in the art, therefore a more detailed description is not necessary.

The output of the reception means is connected to monitoring and control means 26, for example a microprocessor which stores the information received, processes it and performs any operation necessary to possibly control and command the various components of the terminal such as the display 16 for example. The microprocessor can be connected to other elements of the terminal 14 (not shown) or to external peripherals (not shown) which, for example, process the data or store it.

In the example shown in FIG. 2, the terminal 14 further comprises transmission means 28 connected to an input of the attenuator 22 and to the control and command means 26 which store the information to be transmitted and apply it to the transmission means 28. They mainly comprise an amplifier stage and an HF filter for filtering the harmonics of the signal to be transmitted. The transmission means are well known to those skilled in the art and their detailed description is not necessary.

On reception, the signal received by the antenna 20 is transmitted to the attenuator 22. The attenuation rate in normal operation is zero. In the evaluation mode of the communication link, the attenuation rate is directly applied by the operator by action on a push button 18 provided for this purpose or by means of the microprocessor 28 triggered by action on a button. pusher 18 provided for this purpose, or by any other appropriate command, including software. If the tests are carried out by an installer, the attenuation rate is for example variable in order to determine the operating margin and the correct behavior of the communication modules in connection with the terminal. When carried out by a remote reading operator, the attenuation rate is preferably chosen at a fixed value. The signal attenuated or not, depending on the operating mode chosen, is then applied to the reception means 24 which process it in the usual way and transmit the processed signal to the microprocessor 26.

In transmission, the microprocessor 26 communicates to the transmission means 28 the data to be transmitted as well as any useful command or information. The data are processed in the usual way by the transmission means and applied to the attenuator 22, the attenuation rate of which depends as previously on the operating mode chosen. The attenuator 22 delivers the signal to be transmitted to the antenna 20 for transmission.

The attenuator can be of any known type, for example the attenuator marketed by the company Signal Technology Corporation under the reference DAT-9001, or that marketed by the company M / A-COM under the reference AT20-0106 or even that marketed by the company ELHYTE under the reference 50AP-016. As the attenuators and their operating principle are well known to those skilled in the art, it is unnecessary to describe them in detail.

According to an exemplary implementation of the invention, when an installer or a remote reading operator provided with a terminal 14 wishes to carry out an evaluation of the communication link, it suffices to select this function by acting on a push button 18 provided for this purpose - or any other appropriate control means - when the drop-down menu displayed on the display 16 proposes it.

Initially, the steps implemented will be described when the terminal operates as a receiver only. By hypothesis therefore, a communication module 10 transmits a signal which is received by the terminal 14: the communication link is therefore established under certain operational conditions. In other words, the temperature, the distance between the module 10 and the terminal 14, the electromagnetic environment as well as all the extrinsic parameters which can vary the quality of the communication link are in a given state and must remain substantially in this state during of the evaluation. To evaluate the connection, the terminal 14 acts in a controlled manner on the reception communication parameter, namely the reception sensitivity, by attenuating the latter by action of the attenuator 22 on the reception channel.

Two evaluation modes are for example offered via the drop-down menu under the control of the microprocessor 26, or by any other appropriate means.

In the first mode, under the control of the microprocessor 26, the attenuator 22 applies in a controlled manner an increasing attenuation rate to the received signal. The attenuation rate can vary between 0 and 80 dB for example. The attenuation is therefore more and more important and continues to increase as long as the link is established.

The reception means 24 usually comprise an interface, often designated UART, which allows recognition of the messages received. If during a given period of time, no message is recognized by the UART as being a message coming from a communication module, it is considered that the connection is not established.

By varying the attenuation rate, it is therefore possible to evaluate an attenuation value from which the link is broken. This limit value corresponds to the operating margin. The greater this margin, the less likely the route is to be affected by variations in operational conditions.

By measuring the attenuation rate at the break of the link, the microprocessor 26 determines an operating margin which is displayed in dB on the display 16.

In this way, during the evaluation, messages reflecting the link quality as a function of the attenuation rate can be displayed. These messages are for example:

"Good communication" if the connection is deemed satisfactory, ie if the UART recognizes a message sent by a communication module; or "communication limit" if for example after receiving a message interfered with, not recognized by the UART, a message is recognized by the UART, as coming from the communication module concerned.

In a second mode, under the action of a command for example carried out by pressing an appropriate push button 18 or in an equivalent manner controlled by the microprocessor 26, the attenuator 22 applies in a controlled manner a fixed attenuation rate, for example 6 dB. This value of the attenuation rate is chosen as being representative of the usual disturbances which the connection may undergo. It takes into account for example the aging of the components, including the drop in voltage of the batteries supplying the communication module, the possible temperature variations and overall any other type of disturbance. Thus, the quality of the link analyzed by the microprocessor 26 after application of the attenuation rate is displayed by the display 16. A communication link considered satisfactory even after application of the attenuation makes it possible to predict a good establishment of the same link. if operational conditions change.

Therefore, by applying the method according to the invention, the remote reading operator or the installer can quantify the quality of the communication link.

The operating modes described above can be directly transposed to evaluate the communication link when the terminal is operating in transmission. In this case, the communication parameter to which the attenuator 22 applies attenuation in a controlled manner is the transmission power of the transmission channel of the terminal.

As before, the attenuation rate can be variable and increasing between a range of 0 and 80 dB and applied until the microprocessor 26 detects the link break. An operating margin is then obtained calculated by the microprocessor 26 and displayed by the display 16. The attenuation rate can also be fixed at a value determined as above. The procedures described above can also be directly transposed to the case where the attenuator 22 applies attenuation both to the transmission power and to the reception sensitivity.

If evaluation tests are carried out during each pass of the remote metering operator, while preserving the past results, statistics can be made on the evolution of the link, which possibly makes it possible to detect anomalies or prevent failures .

By applying the method of the invention, the remote reading operator can easily estimate the quality of the communication link and possibly prescribe or carry out a maintenance action if the link does not have a sufficient operating margin. The implementation of the method can be carried out with conventional remote metering terminals which have undergone modifications which do not entail any significant additional cost.

The method can also be applied when installing meters on site, to ensure proper functioning of all communication modules with a terminal.

Claims

; CLAIMS

1. Method for evaluating a communication link between a communication module (10) connected to a counter (12) and a remote metering terminal (14), characterized in that it consists in:

* establish the communication link between module (10) and terminal (14) under given operational conditions,

• under substantially the same operational conditions, act in a controlled manner on at least one of the communication parameters of the terminal (14) and detect whether the communication link between module (10) and terminal

(14) is established.

2. Evaluation method according to the preceding claim, in which one acts in a controlled manner on at least one of the communication parameters of the terminal (14) until the communication link is no longer established.

3. The evaluation method as claimed in claim 1, consisting in attenuating the value of at least one communication parameter of the remote reading terminal (14) by a fixed number of decibels.

4. Evaluation method according to any one of claims 1 to 3 in which the controlled action consists in attenuating the transmission power of the remote reading terminal (14).

5. Evaluation method according to any one of claims 1 to 3 wherein the controlled action consists in attenuating the reception sensitivity of the remote reading terminal (14).

0 6. evaluation method according to any one of claims 1 to 3 wherein the controlled action consists in simultaneously attenuating the transmission power of the terminal (14) and its sensitivity in reception.

7. Remote reading terminal for the implementation of an evaluation method according to any one of claims 1 to 6, comprising at least one antenna (20) and reception (24) or transmission / reception means (28,24) of a signal connected to the antenna (20), characterized in that it further comprises an attenuator (22) capable of attenuating in a controlled manner the reception sensitivity of the terminal (14), or the transmit power, or receive sensitivity and transmit power.

8. Remote reading terminal according to claim 7 wherein said attenuator (22) is programmable.

9. Remote meter reading system for implementing a method for evaluating a communication link according to any one of claims 1 to 6 and comprising at least one remote metering terminal according to any one of claims 7 or 8.