Apparatus for the monitoring of a digital signal transmission network and transmission network including such a measuring apparatus

CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 Metrology device for the automatic monitoring of a digital signal broadcasting network and broadcasting network comprising such a metrology device The invention relates to a metrology device for automatic monitoring of a broadcast network. The invention can in particular be used for monitoring the quality of broadcast signals, such as audio and / or video, digital or analog signals.

The network can be a broadcast network, a cable network, etc.

A broadcasting network comprises in a known manner a set of relay stations which receive a signal broadcast by an upstream station or a transmitting head-end station and propagate it to downstream stations and / or to a receiver such as a television for example.

The area covered by the broadcast signal depends of course on the number of relay stations and their geographical distribution.

The broadcast signals are most often multiplexed signals comprising one or more audio and / or video components and / or data.

The audio and / or video components relate for example to 2o radio or television programs.

The data are for example user data, intended for a user receiving the broadcast signal.

The data can also be control data intended for network equipment receiving the broadcast signal. relay stations, TV decoder, etc.

Audio, video and user data components have no particular meaning for broadcast network equipment.

On the other hand, the control data control the operation, define an adjustment, etc ... of the equipment for which they are intended.

CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 2 A remote management network generally complements the broadcast network with the aim of monitoring the operation of the equipment of the broadcast network and of controlling them by remote control.

To do this, the equipment of the broadcast network provided with an appropriate communication interface is connected to a management device via an external communication network, for example a telephone network.

A monitoring network is usually provided as a complement, in particular with the aim of controlling the quality of the broadcast signal (determination of any degradation), in order then to restore this quality if necessary.

In a known manner, such a monitoring network comprises a set of metrology devices installed in key locations of the broadcast network, for example in the vicinity of certain relay stations.

All metrology devices are connected to a supervision device via an external communication network (for example a telephone network).

The supervision device of the surveillance network and the management device of the remote management network can be one and the same device, performing all the functions of both.

FIG. 1 shows a simplified diagram of a monitoring network comprising a monitoring device 110 and two measuring devices 120, 130 intended for monitoring a broadcast signal 100.

A monitoring network such as that of FIG. 1 is mounted in a star. the supervision device controls all the metrology devices which return to it on request information on the quality of the signal broadcast in the geographical area which they have studied.

The broadcasting network supervision device brings together all the metrology devices which, CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 3 on their own initiative or on request, can communicate information to it.

More generally, the monitoring device manages the entire monitoring network by providing the following two main functions. a control function for metrology devices (request for information from metrology devices, adjustment of a metrology device, etc.) and an information processing and alarm function (use of the information received, feedback to a person responsible for supervising the broadcasting network, etc.).

As we have just seen, the monitoring of a broadcasting network, as it is currently carried out, requires the construction of a monitoring network parallel to the broadcasting network to be monitored and which is added (either in terms of links , or in terms of load) to the remote management network which accompanies the broadcasting network.

This correspondingly increases the cost of installing the broadcast network.

The search for a reduction in installation costs has led to the use of an external communication network (for example a telephone network).

While this solution makes it possible to reduce costs, it nevertheless entails technical difficulties due essentially to the fact that the times for routing a communication on an external communication network are poorly controlled.

For example, this solution does not make it possible to synchronize or coordinate reliably the operation of several metrology devices.

Finally, the links between the metrology devices of the monitoring network necessarily pass through the central monitoring device, and therefore through the external communication network.

CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 4 An object of the invention is to provide a metrology device that can be integrated into the main broadcast network.

Another object of the invention is to provide metrology devices capable of performing operations synchronized on a broadcast signal.

Another object of the invention is to achieve the control of a metrology device in a different way, without going through the supervision device of the monitoring network. The use of the external communication network is then limited to actions for which the precision of the routing times is not essential and the load of the supervision device is reduced.

With these objectives in view, the invention relates to a metrology device (200) for monitoring an upstream broadcast signal comprising a main component and upstream control data.

The metrology device includes.

- an extraction circuit (220), to extract the upstream control data from the upstream broadcast signal and provide an upstream instruction, - a measurement circuit (230) to perform a measurement of a parameter of the upstream broadcast signal as a function of the upstream instruction and provide a measurement result.

According to the invention, the metrology device also comprises.

- a control circuit (250), to produce a downstream instruction from the measurement result and an upstream result produced by the extraction circuit (220) from the upstream control data, - an insertion circuit (240), to produce a downstream signal to be broadcast comprising on the one hand the main component of the upstream broadcast signal and on the other hand downstream control data comprising the downstream instruction.

CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 The control data can also include the upstream result and / or the measurement result.

5 A metrology device according to the invention can thus be controlled directly by means of the broadcast signal that it monitors, and it can in addition control a possible metrology device or equipment of the broadcast network via l0 l 'downstream instruction that it inserts in the signal to be broadcast upstream.

With the invention, all the communications related to the control of the metrology devices and / or of the equipment of the broadcast network pass through the broadcast signal.

The network for monitoring the quality of the signal broadcast by the broadcasting network can therefore be lightened because the monitoring device of the monitoring network and the external communication lines are no longer used to perform the control function of the metrology devices.

All the problems linked to the use of an external communication network for the control function are thus solved. information transmission time, synchronization of several metrology devices, costs, etc.

This also makes it possible to envisage a more detailed study of the diffused signal, for example, measurements in synchronism of the diffused signal could be envisaged for several metrology devices.

Measurements of subjective quality, of error rate thus become possible with the invention.

With the invention, the monitoring network only performs a function of processing the information received from the metrology and alarm devices if necessary.

CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 6 According to embodiments of the metrology device, the downstream instruction can be.

- an instruction for controlling the operation of a relay station or a final receiver of the broadcast network, receiving the signal to be broadcast downstream, or - a command for a measurement to be carried out on the signal to be broadcast downstream, or - a updating, partial or complete, of the internal functions of downstream metrology devices.

The invention also relates to a broadcasting network, comprising at least one metrology device as described above.

The broadcasting network can also include a metrology device of rank N1 (320) and a metrology device of rank N2 (330, 340) strictly greater than N1. The upstream instruction produced by the extraction circuit (220) of the rank N2 device (330) then corresponds to the downstream instruction produced by the control circuit (250) of the rank N1 metrology device (320).

By rank of a metrology device, it is necessary to understand here the position of said device with respect to a network head station.

Thus, the device of rank N2 higher than N1 receives the broadcast signal after the device of rank N1 has received it, possibly modified, and transmitted.

The rank N2 device is said to be downstream from the rank N1 device.

According to the invention, the rank N1 device can control the operation of the rank N2 device.

The device N1 can also more simply provide the device of rank N2 with a measurement result to be used, or simply to be transmitted.

The broadcast network also includes a head-end station for transmitting the broadcast signal and the upstream instruction extracted by the extraction circuit of the rank N1 metrology device is for example CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 7 an instruction inserted in the signal broadcast by the head-end, or by a metrology device of rank NO associated with the head-end.

The broadcast network also comprises a final receiver for receiving and using the broadcast signal, and the downstream instruction produced by the control circuit (250) of the metrology device (200) of rank N2 is for example intended to control the operation of the final receiver.

The final receiver is, for example, a final monitoring receiver.

The invention will be better understood and other characteristics and advantages will appear on reading the description which follows, of an exemplary implementation of a metrology device and of a broadcasting network according to the invention.

The description should be read in conjunction with the accompanying drawing in which.

- Figure 1, already described, is a diagram of a known monitoring network of a broadcast network, - Figure 2 is a diagram of a metrology device, according to the invention, and - Figure 3 is a partial simplified diagram of a broadcasting network according to the invention.

A metrology device 200 according to the invention is shown in FIG. 2.

The device 200 allows the monitoring of an upstream broadcast signal 210.

In one example, the upstream signal 210 is a multiplexed signal comprising in particular an audio component 212 and a video component 214 relating to a television channel, and control data 216.

The audio component 212 and the video component 214 form the main broadcast signal.

The device 200 comprises a data extraction circuit 220, a measuring circuit 230, a data insertion circuit 240, a control circuit 250.

CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 8 The extraction circuit 220 receives the upstream broadcast signal 210, extracts the control data that it contains and provides an upstream instruction.

The measuring circuit 230 performs, as a function of the upstream instruction, one or more measurements of one or more parameters of the upstream broadcast signal 210, in particular on the audio 212 and / or video components 214 of the upstream broadcast signal 210.

The device 230 then provides a relative downstream result aulx) parameters) studied) of the upstream broadcast signal 210, as a function of the upstream instruction.

The extracted driving data can be control instructions for the measuring circuit 230;

the device 230 can in this case be a simple means of measuring one or more parameters of audio and / or video components (quality, power, etc.) meter.

The measurement result is then the direct result of the measurements carried out.

In one example, an instruction is of the type "measure the quality of the image of the video component", the measurement result is in this case a quality score which is then broadcast to stations and / or metrology devices. downstream, after insertion into the upstream broadcast signal.

The extracted control data can be synchronism control instructions (for example "locate the image Y in the video component"), thus making it possible to carry out a study of a precise extract of the broadcast signal. It is then possible to synchronize the action of measuring circuits of several metrology devices, for example to perform the same measurement on the main broadcast signal, on the same extract of the broadcast signal (same image or group of images of the component video, or even extracted from the audio signal, but at different times, but shifted in time because of the propagation times in space of the broadcast signal).

The control data extracted by the device 220 can also be upstream measurement results CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 9 associated with control instructions for the measurement circuit 230; in one example, the upstream result is "the reference signal is equal to Y0, the error rate at time TN-1 is equal to RN - YN-1 / YO"; the upstream instruction is. "calculate the error rate RN - YN / YO at time TN, then calculate the degradation of the error rate RN - RN-1.

The device 230 can in this case be a means for measuring the quality of the video component, associated with a comparator.

The downstream result supplied by the measurement circuit is then the result of the comparison.

The upstream instruction and / or the upstream result are contained in the upstream broadcast signal.

They were introduced into the broadcast signal.

- either via the network head station, - or via another metrology device N1 located between the head station and the device N2 which receives it.

The control circuit 250 receives the upstream measurement result and the downstream result (if any) supplied by the device 230, and in return it produces a downstream instruction.

Like the upstream instruction, the upstream result is extracted from the upstream broadcast signal by the extraction circuit 220.

The upstream result has for example been introduced into the broadcast signal by an upstream metrology device according to the invention, which scans the broadcast signal and which is located upstream of the metrology device receiving the upstream results.

The downstream instruction can include instructions for controlling a measuring circuit and / or a relay station and / or an end receiver (example future frequency change of the broadcast signal, reinitializing a measuring circuit). The downstream instruction can also include measurement results obtained by the measurement circuit 230 associated with the control circuit 240, or else by a measurement circuit located in CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 upstream of it. All of these results can be used subsequently by another measurement circuit receiving the downstream signal (to perform a comparison, for example), or else be stored by a final monitoring receiver for later use.

The insertion circuit 240 receives the downstream result, and the downstream instruction and produces a downstream signal 218 to be broadcast, comprising an audio component and a video component identical to those corresponding to the upstream signal 210, and comprising driving data.

The control data include in particular the downstream instruction and / or the downstream result.

It will be noted that the control data contained in the downstream signal may be partially or totally different from those of the upstream signal.

A metrology device according to the invention is thus able to extract control data from the upstream signal and to produce, after processing, a downstream signal comprising control data updated by the control circuit and the measuring circuit.

Thus, the control circuit of a metrology device 200 of rank N1 makes it possible to control a final receiver and / or a downstream metrology device of rank N2> N1 as a function of measurement results acquired at rank N1, or even upstream of the rank N1 device.

By rank of a metrology device, it is necessary to understand here the position of a device with respect to the transmitting station.

For example, a device of rank N2> N1 receives the broadcast signal after the device of rank N1 has received and transmitted it.

In general, a metrology device according to the invention has the following characteristics.

- it can carry out, on the broadcast signal, measurements whose corresponding control instructions are conveyed by the main signal itself, CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 11 - it can transmit control instructions and / or measurement results to downstream metrology devices and / or to any downstream equipment of the broadcast network.

A broadcasting network according to the invention comprises, as well as a known network, a head station, to transmit the signal to be broadcast, at least one final receiver, to receive and use the broadcast signal, and possibly one or more stations. relay, to receive the broadcast signal and transmit it identically.

A broadcasting network according to the invention also comprises a set of metrology devices according to the invention distributed in the broadcasting zone covered by the broadcast signal.

FIG. 3 presents in a simplified manner a part of a broadcasting network according to the invention, which comprises in particular a relay station 310 and three metrology devices 320, 330, 340 produced according to the diagram of FIG. 2.

The metrology devices are located in Figure 3 in the vicinity of the relay station and no scale is respected, for the sake of clarity of Figure 3.

In practice, the devices 320, 330, 340 can be located between a few centimeters and a few tens of thousands of kilometers from a relay station.

The relay station 310 receives the signal 350 broadcast downstream of rank N-1 and identically retransmits three signals 360, 361, 362 broadcast upstream of rank N in three main directions.

Of course, in practice and in a known manner, the relay station can retransmit the broadcast signal in more than three main directions, in a half-plane, etc.

The metrology device 320 of rank N-1, receives an upstream broadcast signal of rank N-1, propagated by equipment not shown in the network, and returns the CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 12 signal 350 downstream of rank N-1, in which it has possibly modified the control data.

The metrology device 330 of rank N receives the broadcast signal 360 upstream of rank N and returns the downstream signal 370 of rank N, in which it has possibly modified the control data.

Likewise, the metrology device 340 receives the broadcast signal 361 upstream of rank N and returns the downstream signal 380 of rank N, in which it has possibly modified the control data.

It should be noted that the signals 370, 380 can include different control data because these data are modified, possibly in a different way, by different metrology devices.

The devices 320, 330, 340 are made according to the diagram of Figure 2 and operate in a similar manner.

First of all, they receive an upstream broadcast signal and extract (extraction circuit 220) data for controlling the upstream instructions and / or the upstream results.

They then perform measurement operations (measurement circuit 230) on the audio and / or video components of the broadcast signal as a function of the upstream instructions extracted. They may possibly determine downstream instructions for controlling downstream metrology devices.

Finally, they insert new control data (measurement results and / or downstream instructions) into the broadcast signal, thus forming a downstream broadcast signal.

All the metrology devices are controlled as a function of the control data included in the upstream broadcast signal that they receive.

These control data may include, depending on the case, instructions initially inserted into the main signal broadcast by a network headend station, instructions inserted by one or more lower level metrology devices (ie located between the head station and the metrology device concerned) in the broadcast signal CA 02469747 2004-06-08 WO 03/051004 PCT / FR02 / 04277 13 during its propagation.

Furthermore, the measurement results (all or only the relevant results as the case may be) are transmitted to a final receiver and / or to one or more downstream metrology devices via the broadcast signal.