FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
& The Patent Rules, 2003
COMPLETE SPECIFICATION
1.TITLE OF THE INVENTION:
METHOD FOR CONTROLLING THE LOAD OF A DATA CONCENTRATION
GATEWAY FOR A WIRELESS COMMUNICATION NETWORK
2. APPLICANT:
Name: KERLINK
Nationality: France
Address: 1 rue Jacqueline Auriol, 35235 THORIGNE-FOUILLARD, France.
3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in
which it is to be performed:
2
Technical field
The invention relates to the field of methods and devices 5 for wireless data
communication, notably in the field of the internet of objects. More particularly, the
invention relates to the field of data concentration gateways for a wireless
communication network and the control of these gateways.
Prior art
10 The internet of objects consists in enabling everyday objects to
communicate data automatically using a wireless network. For example, a water
meter equipped with a communication module may automatically communicate a
water reading to the business in charge of billing for water consumption.
Gateways, also called base stations, have the purpose of allowing the
15 wireless reception and transmission of data from and to communication modules
present in their coverage area, and relaying these data to devices responsible for
processing them, for example servers that can be accessed on a network based on
the IP protocol (“internet protocol”).
A number of wireless access technologies are available for the
20 implementation of networks communication modules. The LoRa™, Sigfox™ or WMBus
(from the English “Wireless Meter Bus”) technologies, which are based, notably,
on different types of modulation, may be mentioned here purely by way of illustration
and without limiting intent.
These technologies have the common feature of providing long distance
25 (called “long range” in English) communications, making it possible to reduce the
number of gateways while increasing their coverage.
However, the communication between the communication modules and the
gateway on the one hand, and between the gateway and the remote devices
responsible for processing the data passing through the gateway on the other hand,
30 are based on different communication protocols. The gateway must therefore
demodulate the signals that it receives from the different communication modules
3
present in its coverage radius before transmitting the corresponding information to
the different remote devices involved. For this purpose, these signals are processed
by different demodulators incorporated in the gateway. However, the number of
signals that can be processed simultaneously by a gateway in good conditions is
limited by the number of demodulators that it contains. Moreover, 5 the number of
signals to be processed simultaneously by the gateway may vary over time. A
method is therefore required for controlling the load on a gateway.
Summary
The present invention enables this requirement to be met.
10 For this purpose, the invention provides a method for controlling the load on
a data concentration gateway for a wireless communication network, the method
comprising:
- receiving a plurality of data signals from a plurality of remote client
devices,
15 - providing a communication start date for each data signal received,
- selecting a received data signal,
- determining a communication end date for each data signal received,
- determining a number of data signals received by the gateway that
have a communication end date lying between the communication start
20 date of the selected data signal and the communication end date of the
selected data signal,
- comparing said number of data signals with a threshold number, and
- transmitting an alarm signal in response to the detection that said
number of data signals is greater than the threshold number.
25 Because of these characteristics, an alarm is transmitted as soon as the
load on the gateway exceeds a threshold number of simultaneously processed
signals. These characteristics therefore make it possible to check that the load on
the gateway does not exceed a predetermined threshold.
According to other advantageous embodiments, such a method for
30 controlling the load on a data concentration gateway may have one or more of the
following characteristics:
4
According to one embodiment, the gateway comprises a plurality of
demodulators, each demodulator of the gateway being configured to demodulate
data signals received by the gateway, the method further comprising a step of
demodulating the plurality of data signals by the demodulators.
According to one embodiment, the threshold number 5 corresponds to the
number of demodulators in the gateway. Thus the control method makes it possible
to check that the number of signals processed simultaneously by the gateway does
not exceed the number of demodulators that can process said data signals.
According to one embodiment, the gateway comprises a wireless
10 communication interface configured to receive the plurality of wireless data signals,
the wireless communication interface being connected to the demodulators, the
method comprising a step of transmitting each of the data signals received by the
communication interface to a respective demodulator.
According to one embodiment, the gateway further comprises an antenna
15 for receiving the signals.
According to one embodiment, the receiving antenna is configured to
receive data signals at a frequency within the frequency group of 433 MHz, 868
MHz and 915 MHz.
According to one embodiment, each data signal is a frame of a
20 communication protocol chosen from among LoRa technology, Sigfox technology
and WM-BUS technology.
According to one embodiment, determining the communication end date of
each received data signal comprises, for each received data signal:
- determining a length of the frame corresponding to said received data
25 signal, and
- calculating the communication end date of the frame corresponding to
said received data signal as a function of said frame length and of a
data rate of a wireless channel via which said data signal has been
received.
30 According to one embodiment, the gateway comprises an internal clock
capable of providing a time stamp data element corresponding to the
communication start date of each data signal received.
5
According to one embodiment, the control method further comprises storing
the communication end date of each data signal of the plurality of data signals in a
memory of the gateway.
According to one embodiment, the gateway control method further
5 comprises:
- receiving synchronization data from a remote device connected to the
gateway,
- synchronizing the internal clock of the gateway on the basis of the
synchronization data.
10 According to one embodiment, the invention also provides a data
concentration gateway for a wireless communication network comprising a set of
remote client devices transmitting data signals, the concentration gateway
comprising:
- a wireless communication interface configured to receive wireless data
15 signals from the set of client devices,
- a plurality of demodulators configured to demodulate the data signals
received by the communication interface,
- a control unit configured to execute the aforesaid control method.
According to one embodiment, the concentration gateway further
20 comprises a network interface connected to a remote network and configured to
transmit the demodulated data signals.
According to one embodiment, the concentration gateway further
comprises an alarm configured to send an alarm data signal to a gateway
management device connected to the gateway. Such a gateway management
25 device is, for example, connected to the gateway via the remote network. Such a
gateway management device may be connected to a plurality of gateways.
Some aspects of the invention are based on the idea of providing a method
for controlling the load on a gateway. Some aspects of the invention are based on
the idea of transmitting an alarm if a gateway overload is detected. Some aspects of
30 the invention are based on the idea of determining the number of data signals
processed simultaneously by the gateway. Some aspects of the invention are based
6
on the idea of checking that the number of data signals received and processed
simultaneously by the gateway does not exceed the number of demodulators in the
gateway. Some aspects are based on the idea of monitoring the gateway load for
each data signal received by the gateway.
Brief description 5 of the drawings
The invention will be better understood and other objects, details,
characteristics and advantages thereof will be more readily apparent from the
following description of some specific embodiments of the invention, provided solely
for illustrative purposes and in a non-limiting way, with reference to the attached
10 drawings.
- Figure 1 is a schematic representation of an interconnection between
a wireless local area network and a wide area network via a concentration gateway;
- Figure 2 is a schematic functional representation of the concentration
gateway of Figure 1;
15 - Figure 3 is an operating diagram of a method for controlling the load
on the gateway of Figure 2;
- Figure 4 is a graph showing a plurality of frames received by the
gateway of Figure 2 in a given period.
Detailed description of embodiments
20 In Figure 1, a first wireless local area communication network (WLAN, for
“Wireless Local Area Network”) 1, referred to hereafter as the wireless local area
network 1, is interconnected with a wide area communication network 2 (WAN, for
“Wide Area Network”), for example the internet, by means of a gateway 3. This
gateway 3 comprises network interfaces enabling it to belong to both the wireless
25 local area network 1 and the wide area network 2.
In addition to the gateway 3, the wireless local area network 1 comprises a
set of communicating objects 4, shown in Figure 1, by way of illustration, as being
four in number. These communicating objects 4 may be, for example, wireless
sensors such as water meters, gas meters, or other meters. These communicating
30 sensors, equipped with wireless communication modules, may thus, according to
their characteristics, communicate measured data, such as a reading of a water, gas
or other meter, to the concentration gateway 3. These communicating objects 4
7
have the distinctive characteristic of consuming very little energy, being commonly
called “low consumption” objects, and of using communication means with a very
low data rate, of less than 2 kbps for example.
The communicating objects 4 mostly run on batteries or accumulators. To
optimize their power consumption, the time periods during which 5 the communicating
objects 4 can transmit or receive data are limited. Outside these transmission and/or
reception periods, the communicating objects 4 are, for example, on standby,
thereby reducing their electricity consumption. In the context of Figure 1, the
wireless local area network 1 is, for example, a Zigbee network, a LoRa network, a
10 Bluetooth network of the conventional or low energy (Bluetooth Smart) type, or any
other network not based on the IP communication protocol. However, this wireless
local area network 1 is an explicit network; that is to say, each communicating object
4 may be identified uniquely in this wireless local area network 1 by means of its
own identifier, for example a MAC (from the English “Media Access Control”)
15 address.
For its part, the wide area network 2 is based on the IP communication
protocol, being a network such as the internet or a 3G/4G or other communication
network. This wide area network 2 comprises, in addition to the gateway 3, remote
devices 5 such as servers, DNS (“Domain Name System”) servers, database
20 storage devices, or others. Each remote device 5 connected to this wide area
network 2 is identified by an IP address. The remote devices 5 are configured for
collecting and processing information from some or all of the various communicating
objects 4 present on the wireless local area network 1.
Since the wireless local area network 1 and the wide area network 2 use
25 heterogeneous communication protocols, the gateway 3 acts as an interface
between the communicating objects 4 and the remote devices 5. Typically, the
gateway 3 acts as a switching platform for carrying data from the communicating
objects 4 to the remote devices 5, and vice versa. The gateway 3 must therefore
have a mechanism for establishing bi-directional communication sessions with, on
30 the one hand, each communicating object 4, as indicated by the arrows 37, and, on
the other hand, the remote devices 5, as indicated by the arrows 38. An example of
a gateway 3 for establishing these bi-directional communications with the
communicating objects 4 and the remote devices 5 is shown in Figure 2.
8
The gateway 3 shown in Figure 2 comprises a plurality of components. In
particular, the gateway 3 comprises a wireless front-end module 6, a baseband
processing module 7, a microcontroller 8, an internal memory 9, a user interface 10,
a GPS 11, a clock 12 and a network interface 13.
The wireless front-end module 6 has the function of 5 transmitting and
receiving radio waves to and from communicating objects 4. For this purpose, the
wireless front-end module 6 comprises at least one wireless antenna (not shown).
This wireless antenna is intended to radiate or capture radio waves carrying the data
to be exchanged with the communicating objects 4 via a wireless transmission
10 channel. The wireless front-end module 6 may, for example, communicate with the
communicating objects 4 on a wireless channel having a frequency of 433 MHz, 868
MHz, or alternatively 915 MHz or another frequency, according to the current
regulations. The wireless front-end module 6 is connected to the baseband
processing module 7 of the gateway 3 in order to be able to transmit to it the
15 wireless signals received by the gateway 3 and receive the data signals to be
transmitted by the gateway 3.
The baseband processing module 7 of the gateway 3 has the function of
preparing the data signals received by the gateway 3 for their processing by the
microcontroller 8. For this purpose, the baseband processing module 7 comprises
20 an arbitration module 14, a plurality of demodulators 15 and a buffer memory 16.
The arbitration module 14 receives all the data signals from the wireless
front-end module 6. The arbitration module 14 is connected to all the demodulators
15. The arbitration module 14 distributes the data signals received by the gateway 3
to the demodulators 15. This distribution of the data signals received by the gateway
25 may be carried out according to numerous distribution criteria. This distribution may,
for example, be carried out on the basis of the availability of the demodulators 15,
the data rate of the data signals, the wireless communication channels, the strength
of the data signals, or other factors.
The arbitration module 14 is capable of simultaneously detecting a plurality
30 of headers of the packets to be demodulated, including in the context of data signals
received at different data rates. However, each demodulator can only demodulate
one packet at a time. Thus the number of packets that can be demodulated
9
simultaneously by the gateway 3 is limited by the number of demodulators 15
incorporated in the gateway 3.
The demodulators 15 incorporated in the baseband processing module 7
may have different characteristics, particularly different programmability
characteristics according 5 to requirements.
Thus, in a first variant, a demodulator 15 may be configurable for using a
given frequency from among a plurality of permitted frequencies. The demodulation
bandwidth of the demodulator 15 may, for example, be configured at 125, 250 or
500 kHz. The data rate permitted by the demodulator 15 may also be configured at
10 any data rate from among a plurality of available data rates. However, only one data
signal having the data rate to which said demodulator 15 is actually configured will
be demodulated. Such a configurable demodulator 15 is preferably intended to act
as a high data rate link to other gateways or remote devices 5.
In a second variant, the demodulator 15 may be designed to operate with a
15 passband that may not be modified or configured, for example a predefined
passband of 125 kHz. However, the data rate of a demodulator 15 according to this
second variant remains adaptable, so that the demodulators 15 according to this
second variant may receive signals at different data rates without preliminary
configuration. The demodulators 15 according to this second variant are preferably
20 dedicated to use in a star network comprising a large number of communicating
objects 4. Preferably, the communicating objects 4 located near the gateway 3 will
use a maximum possible data rate in the fixed passband of 125 kHz (about 6 kbit/s,
for example), whereas the communicating objects 4 distant from the gateway 3 will
use a lower data rate (down to 300 bit/s, corresponding to the minimum LoRa data
25 rate for a channel at 125 kHz).
Preferably, the communicating objects 4 may change their transmission
frequency for each transmission, thus allowing an adaptation of the dynamic data
rate according to the configuration of their link without the addition of complexity.
Furthermore, there is no need to update a table of the data rates used by the
30 different communicating objects 4, because all the data rates are demodulated in
parallel by the baseband processing module 7.
Each packet demodulated by a demodulator 15 is associated with
metadata. These metadata are detected by the baseband processing module 7.
10
These metadata comprise the start date of the packet transmission, the packet
length, and the data rate of the packet transmission. The demodulated packet and
the associated metadata are stored in the buffer memory 16 of the baseband
processing module 7. The baseband processing module 7 is connected to the
microcontroller 8 of the gateway 3 in such a way that the microcontroller 5 8 of the
gateway 3 has access to the buffer memory 16 of the baseband processing module
7.
In the baseband processing module 7, whenever any of the demodulators
15 demodulates a packet, this packet is stored with additional information, called
10 metadata, in the buffer memory 16. The metadata comprise, for example:
- a wireless channel identifier,
- the average signal to noise ratio over the length of the packet (in dB),
- the minimum signal to noise ratio over the length of the packet (in dB),
- the maximum signal to noise ratio over the length of the packet (in dB),
15 - the average signal strength over the duration of the packet (in dB),
- time stamp data for the start of the packet,
- error correction code values,
- an identifier of the demodulator,
- a correlation peak position,
20 - the signal to noise ratio of the detection correlation.
Similarly, the baseband processing module 7 may be used to transmit to
the wireless front-end module 6 the data from the remote devices 5 to be
transmitted by the wireless front-end module 6. An example of a baseband
processing module 7 that can be incorporated into the gateway 3 is the SX1301
25 processor produced by Semtech®, a US company.
The microcontroller 8 is connected to all the elements of the gateway 3 in
such a way as to manage the gateway 3 and allow the data transfer between the
wireless local area network 1 and the wide area network 2. In particular, the
microcontroller 8 may be used to implement the various operating processes of the
30 gateway 3. The programs defining the various operating processes of the gateway 3
11
are, for example, stored in the internal memory 9 of the gateway. These operating
processes may be of any type capable of managing the gateway 3, for example a
process of processing data signals received by the gateway in order to transmit
them to their recipient, a process of synchronizing the gateway 3 using the GPS 11
providing reference data, or a process of synchronizing the various 5 communicating
objects 4 using the clock 12.
The user interface 10 comprises a plurality of input/output means for
configuring the gateway 3. These input/output means are, for example, connectors
such as input or output ports providing access to the internal memory 9, USB
10 connection devices, or other means. The user interface may also comprise humanmachine
interface means such as a control screen, LED lamps indicating the
operating state of the gateway, or other means.
The network interface 13 of the gateway 3 may be used to connect the
gateway 3 to the remote devices 5 via the wide area network 2.
15 The gateway 3 comprises, for example, a battery (not shown) for its power
supply.
Figure 3 is an operating diagram of a method for controlling the load on the
gateway of Figure 2.
As explained above, when the gateway 3 receives a data signal from a
20 communicating object 4, the corresponding packet is transmitted to one of the
demodulators 15 of the baseband processing module 7 to be processed. Each
demodulated packet associated with metadata and stored in the buffer memory 16
of the baseband processing module 7 generates the execution of a method of
controlling the load on the gateway 3 which will now be described with reference to
25 Figure 3.
When the demodulator detects a frame start date ddt1 (step 17), said frame
start date ddt1 is recorded as a metadata element in the buffer memory 16 (step
18). The microcontroller 8 also reads the frame start date ddt1 and determines a
corresponding frame end date dft1 (step 19). For this purpose, the microcontroller 8
30 determines the duration of the frame dt1 (step 20) by any possible means, such a
frame duration dt1 being supplied, for example, by the demodulator 15, by being
included in the metadata. The frame end date dft1 is calculated (step 22) on the
basis of the frame duration dt1, according to the formula
12
dft1 = ddt1 + dt1, where dt1 = , where is the frame length in bits and
ddct1 is the data rate of the channel (in bits per second)
For this purpose, the microcontroller 8 determines the frame length l (in
bits) and the data rate of the channel ddct1 via which the frame traveled. 5 This data
rate of the channel ddct1 is supplied directly by the demodulator 15 on the basis of
its own parameters.
Since the frame end date dft1 has been determined (step 19), the
microcontroller 8 determines the number N of frames received by the gateway 3
10 having a frame end date lying between the frame start date ddt1 and the frame end
date dft1 (step 23). For this purpose, the microcontroller 8 may consult the metadata
stored in the buffer memory 16 of the baseband processing module 7.
The microcontroller 8 then compares the number of frames N, incremented
by 1, with a threshold S, which is, for example, equal to the number M of
15 demodulators 15 present in the gateway 3 (step 24). The incrementation of the
number N by 1 makes it possible to take into account the frame for which the
reception (step 17) of the frame start date ddt1 generated the execution of the
process. The number of demodulators 15 present in the gateway is a known number
M which is, for example, stored in the internal memory 9 of the gateway 3.
20 If this number N+1 is strictly less than the number M of demodulators 15
present in the gateway 3 (step 25), the method terminates without any further action
by the microcontroller 8 (step 26), since the load on the gateway is considered to be
non-critical.
On the other hand, if the number N + 1 is greater than or equal to the
25 number M of demodulators 15 present in the gateway 3 (step 27), the
microcontroller 8 causes an alarm to be transmitted (step 28). Such an alarm may
be produced in any suitable way, for example in the form of a message transmission
to a remote server for managing the gateways 3, a light signal, or an audible alarm
using a loudspeaker incorporated in the user interface 10 of the gateway 3, or by
30 any other suitable means.
13
When an alarm is transmitted (step 28), the personnel responsible for the
management and/or maintenance of the gateway 3 are informed of the overloading
of the gateway 3. A number of responses may then be made to prevent the gateway
3 from remaining overloaded. Thus, demodulators 15 may be physically added to
the gateway 3 to increase its processing capacity and thus increase 5 the threshold
number at or above which an alarm is transmitted. Another solution is to reprogram
the communicating objects 4 to reduce the upload from the communicating objects 4
and thus spread over time the frame end dates received by some of the
demodulators 15, or to shorten the packets transmitted by the communicating
10 objects 4.
The method for controlling the load on the gateway 3 as described above is
preferably executed for each new frame start date detected. Such a method for
controlling the load on the gateway 3 enables the load on the gateway 3 to be
estimated in a simple and economical way. This is because this method enables the
15 load on the demodulators 15 to be determined in real time while having a low
computing cost. This method for controlling the load on the gateway 3 may therefore
be implemented in the gateway 3 without any risk of degrading its performance.
The threshold number for triggering the alarm, that is to say the number S
to which the number N+1 is compared in step 24, may be stored in the internal
20 memory 9 and may represent a value other than the number of demodulators 15
present in the gateway 3. For example, this threshold number may be made to
correspond to the number of demodulators less 2, thus enabling an alarm to be
generated before the point where all the demodulators 15 are saturated.
Figure 4 is a graph showing an example of a plurality of frames received by
25 the gateway 3 of Figure 2 in a given period. In this diagram, the horizontal axis
represents time, and the vertical axis shows different demodulators 15 processing
data signals received by the gateway 3 over time.
This graph relates to the method for controlling the load on the gateway 3
executed after the processing of a frame t3 by a demodulator M3 of the gateway 3.
30 The frame t3 has a frame start date ddt3 and a frame end date dft3, stored in the
buffer memory 16 of the graphic interface 7 or determined by the microcontroller 8
using the metadata associated with the packet corresponding to the frame t3.
Additionally, the execution of the process of controlling the load on the gateway
14
described with reference to Figure 3 comprises the step of determining the number
N of frames whose frame end date lies between the frame start date ddt3 and the
frame end date dft3. As illustrated in Figure 4, only the frames t1 and t2 have a
frame end date, namely dft1 and dft2 respectively, which is after the frame start date
ddt3 and before the frame end date dft3. The other frames have 5 a frame end date
which is after the frame end date dft3. Thus, in the present case, the method for
controlling the load on the gateway executed after the processing of the frame t3 by
the demodulator M3 does not generate an alarm, since the number N+1 of frames
having a frame end date lying between the frame start date ddt3 and the frame end
10 date ddf3, that is to say N=3, is less than the number of demodulators M, which is
six in the case shown in Figure 4.
Although the invention has been described with reference to a number of
particular embodiments, it is evidently not limited in any way to these embodiments,
and comprises all the technical equivalents of the means described and their
15 combinations where these fall within the scope of the invention.
Some of the elements represented, notably the components of the
gateway, may be made in different forms, in a unitary or distributed manner, using
hardware and/or software components. Hardware components that may be used are
ASIC specific integrated circuits, FPGA programmable logic networks, or
20 microprocessors. Software components may be written in various programming
languages, for example C, C++, Java or VHDL. This list is not exhaustive.
The use of the verb “to have”, “to comprise” or “to include” and any of its
conjugated forms does not exclude the presence of elements or steps other than
those stated in a claim.
25 In the claims, any reference sign in brackets is not to be interpreted as a
limitation of the claim.
15
WE CLAIM:
1. A method for controlling the load of a data concentration gateway
(3) for a wireless communication network (1), the method comprising:
- receiving a plurality of data signals from a plurality of remote client
5 devices,
- providing a communication start date for each data signal received,
- selecting a received data signal,
- determining a communication end date for each data signal received
(19),
10 - determining a number of data signals received by the gateway that
have a communication end date lying between a communication start
date of the selected data signal and a communication end date of the
selected data signal (23),
- comparing said number of data signals with a threshold number (24),
15 and
- transmitting an alarm signal (28) in response to the detection that said
number of data signals is greater than the threshold number (27).
2. The control method as claimed in claim 1, wherein the gateway
comprises a plurality of demodulators (15), each demodulator (15) of the gateway
20 (3) being configured to demodulate data signals received by the gateway (3), the
method further comprising a step of demodulating the plurality of data signals by the
demodulators (15), wherein the threshold number corresponds to the number of
demodulators in the gateway (3).
3. The control method as claimed in claim 2, wherein the gateway
25 comprises a wireless communication interface (6) configured to receive the plurality
of wireless data signals, the wireless communication interface (6) being connected
to the demodulators (15), the method comprising a step of transmitting each of the
data signals received by the communication interface (6) to a respective
demodulator (15).
16
4. The control method as claimed in claim 3, wherein the gateway (3)
further comprises an antenna for receiving the signals.
5. The control method as claimed in claim 4, wherein the receiving
antenna is configured to receive data signals at a frequency within the frequency
group of 433 MHz, 868 5 MHz and 915 MHz.
6. The control method as claimed in any of claims 1 to 5, wherein
each data signal is a frame of a communication protocol chosen from among LoRa
technology, Sigfox technology and WM-BUS technology.
7. The control method as claimed in claim 6, wherein determining the
10 communication end date of each received data signal (19) comprises, for each
received data signal:
- Determining a length of the frame corresponding to said received data
signal (20), and
- Calculating the communication end date of the frame corresponding to
15 said received data signal (22) as a function of said frame length and of
a data rate of a wireless channel through which said data signal has
been received.
8. The control method as claimed in any of claims 1 to 7, wherein the
gateway (3) comprises an internal clock (12) capable of providing a time stamp data
20 element corresponding to the communication start date of each data signal
received.
9. A data concentration gateway for a wireless communication
network (1) comprising a set of remote client devices (4) transmitting data signals,
the gateway (3) comprising:
25 - a wireless communication interface (6) configured to receive wireless
data signals from the set of client devices (4),
- a plurality of demodulators (15) configured to demodulate the data
signals received by the communication interface (6),
- a control unit (8) configured to execute the control method as claimed in
30 any of claims 1 to 8.
17
10. The concentration gateway as claimed in claim 9, further
comprising a network interface (13) connected to a remote network (2) and
configured to transmit the demodulated data signals.
11. The concentration gateway as claimed in any of claims 9 to 10, the
gateway further comprising an alarm configured to send an alarm 5 data signal to a
gateway management device connected to the gateway.