FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
& The Patent Rules, 2003
COMPLETE SPECIFICATION
1.TITLE OF THE INVENTION:
COMMUNICATION GATEWAY INTENDED TO CONNECT AN LPWAN
NETWORK AND A CELLULAR 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
Description

5 Technical field
The invention relates to the field of radio
communications or radiocommunications; it relates more
precisely to a gateway connecting a network conforming
to a Low Power Wide Area Network (LPWAN) protocol to a
10 network for accessing a cellular network (Radio Access
Network, RAN); and still more precisely to such a gateway
equipped with filters within the radiofrequency
processing chains (RF chains), which allows it to be
miniaturized.
15
Technological background
In the context of the development of the Internet of
Things, connected objects communicate by radio with the
Internet. The Internet is supported by large
20 infrastructure networks to which the connected objects
must have access through a gateway. The connected objects
are organized in a star formation around the gateway and
connected to the latter by radio. The signals coming from
the connected objects arrive at the gateway on a first
25 interface and pass through it to reach an infrastructure
network via a second interface.
In the present application, it is envisioned that this
infrastructure is a cellular network, for example
conforming to the GSM standard or to a standard which
30 derives from it: essentially 3G, 4G or 5G. The function
of the gateway is therefore as a terminal of a cellular
network and it accesses the core of the network via a
radio channel.
The connected objects must benefit from a long autonomy
35 for the processing of signals and they must be able to
be disseminated over a wide area. The acronym LPWAN which
summarizes these two essential demands (low-power wide
area network, the low power allowing the long autonomy)
is commonly used by those skilled in the art. Thus, the
3
protocols which support the communication of the
connected objects with the Internet must be of the LPWAN
type. The LPWAN network considered in the present
application conforms for example to the standard EN 300
5 220 published by the ETSI. One example of LPWAN protocol
conforming to this standard and whose specifications have
been made public is LoRaWAN®. Strictly speaking, the term
LPWAN is also applicable to the network for accessing the
cellular networks (NB-IoT, LTE-M) but in the present
10 application, it will be reserved for the non-cellular
network to which the gateway is connected.
US 2017230074 discloses such an architecture and a
miniature gateway which connects a LPWAN interface with
a cellular interface. However, the problem of the
15 isolation between the two RF chains is not posed.
Summary
The aim of the invention is to electromagnetically
isolate the two RF chains of a gateway connecting an
20 LPWAN network and a network for accessing a cellular
network, and hence possessing two RF chains respectively
toward two such networks, to a level sufficient to avoid
the degradation of the signal-to-noise ratio on the
receivers of the RF chains when the gateway is miniature.
25 More precisely, the level of isolation sought by the
invention on the LPWAN RF chain is at least 20 dB and
that sought on the cellular RF chain is at least 20 dB.
The frequency bands of the two RF chains of the gateway
are neighboring or even contiguous. For example, in
30 certain European countries, according to the
radiofrequency regulations, the band 915 — 918 MHz may
be used on the LPWAN network and the band 880 — 915 MHz
for the uplink of the cellular network (band 8 of the
LTE). Since neither of the receivers are perfect bandpass
35 filters, they absorb the undesirable radiation in the
frequencies neighboring the useful band hence those
emitted by the other RF chain.
One idea on which the invention is based is to miniaturize
the gateway while at the same time ensuring that it will
4
operate without interference between the RF chains. In
the application envisioned, the Internet of Things, the
gateway has to be small, around 10 cm. The mutual
interference between the RF chains cannot be avoided by
5 the simple solution consisting in moving the antennas
away from each other. This is because it is considered
that, in order to obtain a good electromagnetic
isolation, two antennas must be separated by at least a
quarter of the wavelength that they emit; for example,
10 8.6 cm for a wave of 868 MHz. More generally, as the
wavelength is inversely proportional to the frequency,
the separation of the antennas must be relatively large
for the low frequencies, which is not compatible with the
dimensions of the gateway and the desired frequencies.
15 Another idea on which the invention is based is to isolate
the RF chains essentially by means of a double filtering:
a bandpass filter is introduced into the RF chain of the
LPWAN, in the part common to the reception and to the
transmission, and a rejection filter in the RF chain of
20 the cellular network. The function of each of these
filters is to attenuate the power of the emitted
frequencies which interfere with the other RF chain and
also to immunize at reception each RF chain against the
emissions of the other chain.
25 Another idea on which the invention is based is that
there may be one or more LPWAN networks to which the
gateway gives access and one or more cellular networks
to which the gateway gives access.
According to a first subject, the invention is a
30 communications gateway intended to connect at least one
LPWAN network and at least one cellular network, the
gateway comprising:
• a first RF chain intended to communicate with said
at least one LPWAN network, the first RF chain
35 comprising an LPWAN antenna, a transponder with a
transmitter and a receiver and, installed in series
between the transponder and the LPWAN antenna:
• at least one filtering block, comprising:
5
• an amplification block comprising an uplink
channel and a downlink channel configured in
parallel,
• then, going toward the LPWAN antenna, a part
5 common to the uplink channel and to the
downlink channel, the common part comprising
a bandpass filter passing the frequencies in
a frequency band of said at least one LPWAN
network and attenuating the power of the
10 frequencies outside of the band of said
LPWAN network,
• and a first high-pass filter; and
• a second RF chain toward the cellular network, the
second RF chain being suitable for establishing an
15 uplink and downlink connection with the cellular
network, a frequency band of the uplink and a
frequency band of the downlink being outside of the
frequency band of said LPWAN network, the second RF
chain comprising an antenna, a modem and, installed
20 in series between the modem and the antenna:
• at least one rejection filter attenuating
the power of the frequencies within the
frequency band of said at least one LPWAN
network and passing the frequencies
25 within the frequency band of the downlink
and the frequency band of the uplink of
the cellular network.
According to embodiments, the gateway may comprise one
or more of the features hereinbelow.
30 According to one embodiment, in the second RF chain, the
gateway comprises a single rejection filter and a second
high-pass filter between the rejection filter and the
antenna.
With this high-pass filter, the gateway conforms to the
35 prior art for a cellular RF chain.
According to one embodiment, in the second RF chain, the
gateway comprises a single rejection filter connected
directly to the antenna.
Thus, this embodiment saves one high-pass filter.
6
According to one embodiment, the gateway is able to
connect, on the one hand, a sub-group of LPWAN networks
selected from amongst a group of LPWAN networks operating
in respective frequency bands and, on the other hand, a
5 cellular network.
The transponder of the first RF chain comprises a
respective transmitter-receiver pair for each of the
members of the group of LPWAN networks. The first RF
chain comprises several filtering blocks, each of them
10 being associated with a respective member of the group
of LPWAN networks and comprising an amplification block,
a bandpass filter passing the frequencies in the
respective frequency band of said member of the group of
LPWAN networks and attenuating the power of the
15 frequencies outside of this band. The first RF chain
furthermore comprises a LPWAN network multiplexer,
arranged between the filtering blocks and the first highpass filter.
In the second RF chain, there are several rejection
20 filters configured in parallel and respectively
associated with each of the members of the group of LPWAN
networks, the rejection filter associated with a
respective member of the group of LPWAN networks
attenuating the power of the frequencies within the
25 frequency band of said respective member of the group of
LPWAN networks. The second RF chain furthermore comprises
a first and a second rejection filter multiplexer for
selectively connecting the rejection filters associated
with a sub-group of selected LPWAN networks, which first
30 and second rejection filter multiplexers supervise the
rejection filters, the second rejection filter
multiplexer being on the side of the cellular antenna.
Thus, the gateway is able to create, within its
environment, an LPWAN network potentially operating over
35 several frequency bands.
According to one embodiment, in the variant able to
connect a sub-group of LPWAN networks selected from
amongst a group and a cellular network, the gateway
comprises a control block 16 with a human — machine
7
interface which allows the sub-group of LPWAN networks
to be selected and a control unit configured for
programming the multiplexer of the first RF chain so that
it connects the filtering blocks associated with the
5 respective members of the sub-group of selected LPWAN
networks, and for programming the first and second
multiplexers of the second RF chain so that they connect
the rejection filters associated with the respective
members of the sub-group of selected LPWAN networks.
10 According to one embodiment, in its variant able to
connect a sub-group of LPWAN networks selected from
amongst a group to a cellular network, in the second RF
chain, the gateway comprises a second high-pass filter
between the second rejection filter multiplexer and the
15 cellular antenna.
According to one embodiment, in its variant able to
connect a LPWAN network selected from amongst a group to
a cellular network, the gateway comprises several
rejection filters in the second RF chain and the second
20 rejection filter multiplexer is connected directly to the
antenna.
According to one embodiment of the gateway, said or each
filtering block of the first RF chain furthermore
comprises a channel selector arranged between the
25 amplification block and the bandpass filter and
configured so as to obtain a half-duplex operation in the
frequency band of the LPWAN network or of the respective
member of the associated group of LPWAN networks.
According to one embodiment of the gateway, the bandpass
30 filter of said or of each filtering block is configured
for attenuating by at least 20 dB the power of the
frequencies outside of the band of the LPWAN network or
of the respective member of the associated group of LPWAN
networks.
35 According to one embodiment of the gateway, said or each
rejection filter of the second RF chain is configured for
attenuating by at least 20 dB the power of the frequencies
within the frequency band of the LPWAN network or of the
8
respective member of the associated group of LPWAN
networks.
According to one embodiment, the gateway comprises an
electronic board on which the first RF chain and the
5 second RF chain are installed and whose size does not
exceed 12 cm in the three dimensions.
Thus, the gateway may be miniaturized while being sure
that neither of the RF chains in transmission mode will
interfere with the operation of the other RF chain in
10 reception mode.
According to one embodiment, the gateway according to the
variants or the embodiments hereinabove comprises RF
chains adapted to a separation of at most 8 MHz between
the frequency bands of the cellular networks and the
15 frequency bands of said LPWAN networks.
Thus, the gateway is adapted to the regions of the world
where the legislator has assigned frequency bands
separated by 8 MHz, at the most, for the LPWAN networks
and the cellular networks.
20 According to one embodiment, the uplink or downlink
signals on the first RF chain conform to the standard EN
300 220.
According to one embodiment, the bandpass filter or
filters are chosen from within the group of surface
25 acoustic wave filters, bulk acoustic wave filters and
ceramic filters.
According to one embodiment, the rejection filter or
filters are chosen from within the group consisting of
surface acoustic wave filters, bulk acoustic wave filters
30 and ceramic filters.
According to one embodiment, the isolation of the first
and second RF chains is completed by one or more
techniques for isolation of antennas chosen from within
the group of the decoupling of antennas, of the addition
35 of antenna interference elements, of defected ground
structures, of neutralizing lines, of dielectric
enclosures, of metamaterials.
Brief description of the figures
9
The invention will be better understood, and other aims,
details, features and advantages of the latter will
become more clearly apparent during the following
description of several particular embodiments of the
5 invention, given solely by way of non-limiting
illustration, with reference to the appended drawings.
[Fig.1] shows an overall architecture of a LoRaWAN®
network where a gateway according to the invention is
able to be used.
10 [Fig.2] shows the architecture of the gateway.
[Fig.3] shows the gateway control unit.
[Fig.4] shows the LPWAN RF chain according to a first
embodiment of the invention.
[Fig.5] shows the cellular RF chain according to a first
15 embodiment of the invention.
[Fig.6] shows the LPWAN RF chain according to a second
embodiment of the invention adapted to several LPWAN
networks.
[Fig.7] shows the cellular RF chain according to a second
20 embodiment of the invention adapted to several LPWAN
networks.
Description of the embodiments
In [Fig.1], connected objects 1 communicate with
25 application servers 4.
In one direction, the connected objects 1 transmit data.
The connected objects 1 are, in general, sensors such as
electronic chips for following companion animals, smoke
detectors, water meters, refuse bin inspection chips,
30 vending machine counters, gas meters. They take
measurements which they digitize. They send them to
application servers 4 which store them, apply various
processing operations to them, and then redistribute
them. In the other direction, the application servers 4
35 remotely control the connected objects 1. The typical
data network to which the servers are connected is the
Internet and the typical architecture which implements
this communications configuration is “the Internet of
Things”.
10
In this architecture, the connected objects 1 firstly
communicate via a radio link 5 with a gateway 2. The
radio link 5 between the connected objects 1 and the
gateway 2 is of the LPWAN type and conforms to the
5 standard EN 300 220; for example, and in a non-limiting
manner, it conforms to the public specifications LoRaWAN®
of the LoRa Alliance®, a consortium of industrial
partners who promote these specifications.
The gateway 2 re-transmits the signals 5 coming from the
10 connected objects 1 to an infrastructure network. In the
present application, the infrastructure network is a
cellular network, conforming to the GSM standard or to a
standard which derives from it: 3G, 4G or 5G to mention
the main standards. The gateway 2 is therefore a terminal
15 for accessing a cellular network and communicates with
the core of the cellular network by radio via an access
network 6. The signals 6 reach the core of the cellular
network via access servers 3. The access network at the
core of the cellular network will be abbreviated to
20 “cellular network” in the remainder of the application
unless it is necessary to be more precise.
If it is the application servers 4 that control the
connected objects 1 remotely, the communications follow
the reverse path.
25 The frequencies used in the radio links of the LPWAN
network or of the cellular network depend on the country
where the gateway is operating. They are defined
worldwide by the international treaty, subject of the
Regulations of the ITU-R (International
30 Telecommunications Union, Radiocommunications sector)
which allocates, according to the technical term, in
other words which assigns, the various frequencies to
various Services in the three Regions of the world
(“Regulations”, “Service” and “Region” here are the
35 technical terms of the ITU-R) and imposes radiation
patterns on the transmitters in these frequencies; then,
at the national level, these rules are detailed and the
rights of exploitation of the frequencies are defined.
The frequencies of the cellular networks at a given place
11
are subject to concessions from the local State with a
principle of exclusivity, whereas the LPWAN frequencies
are free to use and may be shared by several operators
who must then coordinate with one another in order to
5 operate together.
“Band” is employed in the following part of the
application as an abbreviation of “frequency band”.
The gateway 2 may be adapted to any coherent set of
national regulations (coherent in the sense that bands
10 of different allocations do not overlap). In one variant,
it may only be adapted to a part of the bands intended
for the LPWAN and for the cellular communications of the
regulations of a single state. In another variant, it may
be adapted to all the bands intended for the LPWAN and
15 for the cellular communications of the regulations of a
given state.
For example, the gateway 2 is adapted to one or more of
the following regulations.
• Europe (Region 1):
20 • Bands of the LPWAN: 868 — 870 MHz, 863 — 870
MHz, 863 — 876 MHz, 915 — 918 MHz or 915 — 921
MHz, depending on the country
• Bands of the cellular network:
• band 8 of the LTE: uplink: 880 — 915
25 MHz; downlink: 925 — 960 MHz
• band 20 of the LTE: uplink: 832 — 862
MHz; downlink: 791 — 821 MHz
• North America (Region 2):
• bands of the LPWAN: 902 - 928 MHz
30 • bands of the cellular network (band 8 of the
LTE): uplink: 824 — 849 MHz; downlink: 869 —
894 MHz
• South America (Region 2), Australia and New Zealand
(Region 3):
35 • bands of the LPWAN: 915 - 928 MHz
• bands of the cellular network
• band 8 of the LTE: uplink: 890 — 915 MHz;
downlink: 935 — 960 MHz
12
• band 5 of the LTE: uplink: 824 — 849 MHz;
downlink: 869 — 894 MHz
• Asia, Thailand, Taiwan and Singapore (Region 3):
• bands of the LPWAN: 920 - 925 MHz
5 • band 8 of the LTE: uplink: 885 — 915 MHz;
downlink: 930 — 960 MHz
The LPWAN networks are symmetrical in the sense that,
being given a frequency usable on such a network, a
10 terminal such as one of the connected objects 1 or the
gateway 2 may transmit or receive at this frequency. The
cellular access networks are asymmetrical: from the
terminal such as the gateway 2 to the core of the network
to which the terminal is subscribed, the term ‘uplink’
15 and, in the other direction, ‘downlink’ are used and the
frequencies of an uplink and of a downlink of the network
are necessarily different.
The architecture and the operation of the gateway are
illustrated in [Fig.2]. The gateway 2 receives signals
20 by radio on its RF chain 10/11 adapted to LPWAN networks,
demodulates them and transmits them along an internal
electrical circuit 15 to the RF chain 20/21, adapted to
cellular networks, which modulates them and transmits
them by radio to the core of the cellular network. The
25 communication may follow the reverse path.
The dimensions of the gateway 2 are preferably of the
order of magnitude of the connected objects 1. Thus, the
applicant has constructed a prototype of the gateway
mounted on an electronic board of around 8 cm.
30 As a transmitter, each RF chain 10, 20 interferes
respectively with the other RF chain 20, 10, as a
receiver. It is therefore useful to electromagnetically
isolate the RF chains 10, 20 from each other, especially
as the gateway 2 is small.
35 [Fig.4] shows the LPWAN RF chain 10 of the gateway 2 in
a first embodiment of the invention. The RF chain 10
comprises a baseband unit, not shown, and a transponder
30. A transmission channel carrying the uplink signal
starts from the point 31 of the transponder and a
13
reception channel carrying the downlink signal arrives
at the point 32 of the transponder. On the transmission
channel, the uplink signal is firstly filtered by a
bandpass filter 40, then amplified by a power amplifier
5 50, then filtered by a low-pass filter 60, by a bandpass
filter 80 and finally by a high-pass filter 90 and it
arrives at the antenna 100. Upon reception, the signal
comes from the antenna 100, it is filtered by the highpass filter 90, then the bandpass filter 80, which are
10 therefore common to the uplink channel and to the
downlink channel, and also to the antenna 100. The
downlink signal is subsequently amplified by a low-noise
amplifier 110 and finally filtered by a bandpass filter
120 before reaching the transponder 30.
15 In the state of the regulations in 2020, in Europe at
least, the transmission and reception frequency bands in
the LPWAN networks are common. The LPWAN antennas
therefore operate alternately in transmission mode or in
reception mode (half-duplex operation) and a selector 70
20 needs to be provided in the RF chain for connecting the
uplink channel or the downlink channel and the part of
the RF chain common to both channels.
The future changes in the regulations on the bands
allocated to the LPWAN will probably allow the use of the
25 LPWAN frequency bands simultaneously in reception and in
transmission (full-duplex operation). The gateway 2 will
then comprise a duplexer instead and in place of the
selector 70 and of the bandpass filter 80.
The elements between the transponder 30 and the selector
30 70 form an amplification block 160. The amplification
block 160, the selector 70 and the bandpass filter 80
form a filtering block. The notions of amplification
block and of filtering block are introduced for the sake
of clarity of the description.
35 The filter 80 allows the bands of the LPWAN to pass upon
transmission and eliminates the bands outside. In
reality, there is no true elimination but an attenuation.
Thus, the filter 80 attenuates the power of the
frequencies emitted by the LPWAN RF chain 10 which
14
interfere with the reception in the cellular RF chain 20,
in other words those that are in the bands of the downlink
of the cellular network.
However, this filter has, in addition, the advantage of
5 attenuating the frequencies emitted by the cellular RF
chain 20 (the frequencies of the uplink of the cellular
network) which interfere with the reception in the LPWAN
RF chain 10.
[Fig.5] shows the cellular RF chain 20 of the gateway 2
10 in the first embodiment of the invention. The RF chain
comprises a modem 120 which includes the baseband unit
and the transponder, a rejection filter 130, and an
antenna 150. It is advantageous to insert a high-pass
filter 140 between the rejection filter 130 and the
15 antenna 150 because it thus still conforms to the prior
art which allows the costs of industrialization to be
reduced. There exists a single channel common to the
uplink signal and to the downlink signal. The modem 120
is universal, adapted to all the cellular frequencies in
20 the world.
The function of the filter 130 is to attenuate the power
of the frequencies emitted by the cellular RF chain 20
(the frequencies in bands of the uplink of the cellular
network) which interfere with the reception in the LPWAN
25 RF chain 10. However, it also has the advantage of
attenuating the frequencies of the LPWAN RF chain 10
which interfere with the reception in the RF cellular
chain 20.
One example of the gateway 2 has been designed and
30 implemented to operate in the band 868 — 870 MHz of the
LPWAN and in the bands of 700 MHz to 2200 MHz of the LTE
cellular networks. The gateway is intended to be used in
the region of the world referred to as EMEA (for Europe,
Middle East, Africa). The bandpass filter 80 inserted in
35 the LPWAN RF chain 10 is a surface acoustic wave filter
(SAW filter) of the model B3430 from the manufacturer
RF360. This filter attenuates the power of the
frequencies emitted in the band of the downlink of the
LTE by at least 40 dB (division of the power by 10,000).
15
The rejection filter 130 inserted into the cellular RF
chain 20 is a surface acoustic wave filter of the model
WFB88C0869FH from the manufacturer NDK, which attenuates
the power of the frequencies emitted in the band of the
5 LPWAN 868 — 870 MHz by an amount of at least 20 dB
(division of the power by 100) and typically by an amount
of 33 dB (division of the power by 2000).
Another example of the gateway 2 has been designed and
implemented to operate in the band 902 — 928 MHz of the
10 LPWAN networks and in the bands 700 MHz to 2200 MHz of
the LTE cellular networks. The gateway is intended to be
used in North America (USA, Canada, Mexico). The bandpass
filter 80 inserted into the LPWAN RF chain 10 is a surface
acoustic wave filter of the model B2672 from the
15 manufacturer RF360. This filter attenuates the power of
the frequencies of the LTE by at least 20 dB (division
of the power by 100) and typically by an amount of 30 dB
(division of the power by 1000). The rejection filter 130
inserted into the RF cellular chain 20 is a surface
20 acoustic wave filter of the model WFH24A0915FE from the
manufacturer NDK, which attenuates the power of the
frequencies in the band 902 — 928 MHz typically by an
amount of 20 dB (division of the power by 100).
These commercial components are mentioned by way of
25 illustration which does not exclude the use of other
ones. Other types of filters could be used such as bulk
acoustic wave filters (BAW filters) and ceramic filters.
The isolation may be completed by antenna design
techniques. The following may be mentioned: decoupling
30 of antennas which allows a level of isolation of 10 to
15 dB at the desired frequencies; passive antenna
elements (radiating elements not electrically powered),
allowing 20 dB of isolation; defected ground structures
(ground is taken in the sense of a neutral electrical
35 point), allowing 20 dB of isolation; neutralizing lines,
allowing 15 dB of isolation; dielectric enclosures,
allowing 15 dB of isolation; “metamaterials” (materials
engineered at the microscopic level in order to obtain
16
good electromagnetic properties), allowing 25 dB of
isolation.
Figures 6 and 7 show a second embodiment of the gateway
2, where the latter is able to connect to a sub-group of
5 LPWAN networks selected from amongst a whole group. The
case may be envisioned of a use for example by a store
manager who would like to group all the meters of his
store (electric meter, gas meter, etc.) into one and the
same network, and the vending machines on a second
10 network.
Each of the networks of the group is characterized by a
respective frequency band.[Fig.6] shows the LPWAN RF
chain 11. It has been shown in a variant adapted to a
group of two LPWAN networks but may easily be generalized
15 to an indefinite number of LPWAN networks. The
transponder 35 comprises a respective transmitter —
receiver pair 36, 37 for each LPWAN network. Each of the
filtering blocks 171, 172 is associated with a respective
LPWAN network and comprises a respective amplification
20 block 161, 162, where necessary a respective channel
selector 71, 72, a respective bandpass filter 81, 82
passing the frequencies within the frequency band of the
respective LPWAN network and attenuating the power of the
frequencies outside of the frequency band of this
25 network. A multiplexer 180 connects the selected
filtering block or blocks 171 or 172 to the part of the
LPWAN RF chain 11 common to all the filtering blocks and
to the antenna 100.
The selection of the sub-group of LPWAN networks is made
30 by means of the control block 16 shown in [Fig.3]. The
user has access to the control block 16 via a human —
machine interface 19. The human — machine interface 19
displays to him/her the group of available LPWAN networks
and the user selects a certain number of them depending
35 on the network or networks that he/she wishes to create.
The human — machine interface 19 transmits the list of
the selected networks to the control unit 18. The control
unit 18 then programs the LPWAN RF chain 11 (and the
cellular RF chain 21 as described hereinbelow) by the
17
command 8. In the LPWAN RF chain 11, it programs the
multiplexer 180, as already described, so that it
connects the sub-group of the selected networks to the
antenna 100 (via other elements).
5 [Fig.7] shows the cellular RF chain 21 in one embodiment
of the gateway 2 where it is able to connect to a subgroup of LPWAN networks chosen from amongst a whole
group. Just like the LPWAN RF chain 11, the cellular RF
chain 21 has been shown in one variant adapted to two
10 LPWAN networks but may easily be generalized to an
indefinite number of LPWAN networks. It comprises several
rejection filters 131, 132 configured in parallel and
respectively associated with each of the LPWAN networks
to which the gateway 2 is able to connecter. The rejection
15 filter associated with a respective LPWAN network
attenuates the power of the frequencies emitted by the
cellular RF chain 21 (the frequencies in the band of the
uplink of the cellular network) which are situated within
the frequency band of this LPWAN network. On either side
20 of the rejection filters 131, 132, there are multiplexers
135, 136 which allow the rejection filter or filters to
be selected, 131 for example, corresponding to the subgroup of selected LPWAN networks. The adjustment of the
multiplexers 135, 136 is therefore linked to that of the
25 multiplexer 180, and when the user chooses a LPWAN
network, all the elements, the filtering block 171 of the
LPWAN RF chain 11, assuming that it is that which has
been chosen, the multiplexer 180 of the LPWAN RF chain
11, the multiplexers 135, 136 of the cellular RF chain
30 21, the rejection filter 131 of the cellular RF chain 21,
assuming that it is that which corresponds to the
filtering block 171 of the LPWAN RF chain, are
conveniently adjusted at the same time.
In fact, the control unit 18 sends to the cellular RF
35 chain 21, for the adjustments that are specific to it, a
command 8 similar to that sent to the LPWAN RF chain. If,
subsequently, the user decides to reprogram the LPWAN RF
chain, a new command 8 will accordingly be sent to the
two RF chains 11, 21.
18
Although the invention has been described in conjunction
with several particular embodiments, it goes without
saying that it is in no way limited to these and that it
comprises all the technical equivalents of the means
5 described, together with their combinations if the latter
fall within the framework of the invention.
The usage of the verb “comprise” or “include” and of its
conjugated forms does not exclude the presence of
elements or of steps other than those stated in a claim.
10 In the claims, any reference sign between parentheses
should not be interpreted as a limitation of the claim.
19
WE CLAIM:
[Claim 1] A communications gateway (2) intended to
connect at least one LPWAN network and at least one
5 cellular network, the gateway comprising:
 a first RF chain (10) intended to communicate
with said at least one LPWAN network, the first
RF chain comprising a LPWAN antenna (100), a
transponder (30) with a transmitter (31) and a
10 receiver (32) and, installed in series between
the transponder and the LPWAN antenna (100):
 at least one filtering block (170),
comprising:
 an amplification block (160)
15 comprising an uplink channel and a
downlink channel configured in
parallel,
 then, going toward the LPWAN antenna
(100), a part common to the uplink
20 channel and to the downlink channel,
the common part comprising a
bandpass filter (80) passing the
frequencies in a band of frequencies
of said at least one LPWAN network,
25 attenuating the power of the
frequencies outside of the band of
said LPWAN network,
 and a first high-pass filter (90); and
 a second RF chain (20) toward said cellular
30 network, the second RF chain being suitable for
establishing an uplink and downlink connection
with the cellular network, a frequency band of
the downlink and a frequency band of the uplink
of the cellular network being outside of the band
35 of said LPWAN network, the second RF chain
comprising a cellular antenna (150), a modem
(120) and, installed in series between the modem
and the antenna:
20
 at least one rejection filter (130)
attenuating the power of the frequencies
within the frequency band of said at least
one LPWAN network and passing the
5 frequencies within the frequency band of the
downlink and the frequency band of the
uplink of the cellular network.
[Claim 2] The gateway as claimed in claim 1, wherein
the second RF chain (20) comprises a single
10 rejection filter (130) and a second high-pass filter
(140) between the rejection filter (130) and the
cellular antenna (150).
[Claim 3] The gateway as claimed in claim 1, wherein
the second RF chain (20) comprises a single
15 rejection filter (130) connected directly to the
cellular antenna (150).
[Claim 4] The gateway as claimed in claim 1,
intended to connect, on the one hand, a sub-group
of LPWAN networks selected from amongst a group of
20 LPWAN networks operating in respective frequency
bands and, on the other hand, a cellular network,
wherein:
 the transponder (35) of the first RF chain (11)
comprises a respective transmitter-receiver
25 pair (36, 37) for each of the members of the
group of LPWAN networks;
 the first RF chain comprises a plurality of
filtering blocks, each of the filtering blocks
(171, 172) being associated with a respective
30 member of the group of LPWAN networks and
comprising an amplification block (161, 162),
a bandpass filter (81, 82) passing the
frequencies within the frequency band of said
respective member of the group of LPWAN
35 networks and attenuating the power of the
frequencies outside of the band of said
respective member of the group of LPWAN
networks;
21
 the first RF chain (21) furthermore comprises
a LPWAN network multiplexer (180), arranged
between the filtering blocks (171, 172) and the
first high-pass filter (90);
5  the second RF chain comprises several rejection
filters (131,132) configured in parallel and
respectively associated with each of the
members of the group of LPWAN networks, the
rejection filter associated with a respective
10 member of the group of LPWAN networks
attenuating the power of the frequencies in the
band of said respective member of the group of
LPWAN networks and passing the frequencies
within the frequency band of the downlink and
15 the frequency band of the uplink of the
cellular network;
 the second RF chain furthermore comprises a
first (135) and a second (136) rejection filter
multiplexer for selectively connecting the
20 rejection filters associated with a sub-group
of selected LPWAN networks, which first (135)
and second (136) rejection filter multiplexers
supervise said several rejection filters (131,
132), the second rejection filter multiplexer
25 (136) being on the side of the cellular antenna
(150).
[Claim 5] The gateway as claimed in claim 4,
furthermore comprising a control block (16), the
control block (16) comprising:
30  a human-machine interface (19) which allows the
sub-group of LPWAN networks to be selected;
 a control unit (18) configured for programming
the multiplexer (180) of the first RF chain
(11) so that the multiplexer (180) connects the
35 filtering blocks (171, 172) associated with the
respective members of the sub-group of selected
LPWAN networks, and for programming the first
and second multiplexers (135, 136) of the
second RF chain so that they connect the
22
rejection filters (131, 132) associated with
the respective members of the sub-group of
selected LPWAN networks.
[Claim 6] The gateway as claimed in either of claims
5 4 and 5, wherein the second RF chain (21) comprises
a second high-pass filter (140) between the second
rejection filter multiplexer (136) and the cellular
antenna (150).
[Claim 7] The gateway as claimed in either of claims
10 4 and 5, wherein the second rejection filter
multiplexer (136) of the second RF chain is
connected directly to the cellular antenna.
[Claim 8] The gateway as claimed in one of claims 1
to 7, wherein said or each filtering block (170,
15 171, 172) of the first RF chain furthermore
comprises a channel selector (70) arranged between
the amplification block (160, 161, 162) and the
bandpass filter (80, 81, 82) and configured so as
to obtain a half-duplex operation in the frequency
20 band of the LPWAN network or of the respective
member of the associated group of LPWAN networks.
[Claim 9] The gateway as claimed in one of claims 1
to 8, wherein said bandpass filter (80, 81, 82) of
said or of each filtering block is configured for
25 attenuating by at least 20 dB the power of the
frequencies outside of the band of the LPWAN network
or of the respective member of the associated group
of LPWAN networks.
[Claim 10] The gateway as claimed in one of claims 1
30 to 9, wherein said or each rejection filter (131,
132) of the second RF chain is configured for
attenuating by at least 20 dB the power of the
frequencies within the frequency band of the LPWAN
network or of the respective member of the
35 associated group of LPWAN networks.
[Claim 11] The gateway as claimed in any one of the
preceding claims, comprising an electronic board on
which the first RF chain (10, 11) and the second RF
23
chain (20, 21) are installed and whose size does not
exceed 12 cm in the three dimensions.
[Claim 12] The gateway as claimed in any one of the
preceding claims, wherein said first (10, 11) and
5 second (20, 21) RF chains are adapted to a
difference of at most 8 MHz between any one of the
frequency bands of the cellular network and the
frequency band of the or each member of the group
of LPWAN networks.
10 [Claim 13] The gateway as claimed in any one of the
preceding claims, wherein the uplink or downlink
signals on the first RF chain conform to the
standard EN 300 220.
[Claim 14] The gateway as claimed in one of the
15 preceding claims, wherein the bandpass filter or
filters are chosen from within the group of surface
acoustic wave filters, of bulk acoustic wave filters
and of ceramic filters.
[Claim 15] The gateway as claimed in one of the
20 preceding claims, wherein the rejection filter or
filters are chosen from within the group of surface
acoustic wave filters, of bulk acoustic wave filters
and of ceramic filters.
[Claim 16] The gateway as claimed in one of the
25 preceding claims, wherein the isolation of the first
and second RF chains is completed by one or more
techniques for isolation of antennas chosen from
within the group of the decoupling of antennas, of
the addition of antenna interference elements, of
30 defected ground structures, of neutralizing lines,
of dielectric enclosures, of metamaterials.