Battery-Operated Stationary Sensor Arrangement with Unidirectional Data
Transmission
Description
Embodiments of the present invention relate to a battery-operated stationary sensor
arrangement with unidirectional data transmission. Further embodiments of the present
invention relate to a hybrid method for a wireless transmission of burst-type data packets
in a stationary multi-user system.
In the transmission of small amounts of data, e.g. of sensor data of a heating, current or
water meter, a radio transmission system may be used. Here, a measurement means with
a data transmitter is attached to the sensor which wirelessly transmits the sensor data to a
data receiver.
US 7,057,525 B2 describes a system for a unidirectional remote counter or meter readout
having two means, one means which generates short transmission packets for the mobile
reception and one means which generates narrow-banded transmission packets
receivable across a larger distance from a stationary receiver. Here, the two signals sent
are only different with respect to signal bandwidth.
It is the object of the present invention to provide a concept which enables an increase of
range.
This object is achieved by a battery-operated stationary sensor arrangement with a
unidirectional data transmission according to claim 1, a system with a battery-operated
stationary sensor arrangement and a data receiver according to claim 8, a method for
transmitting a sensor data packet according to claim 13, and a computer program
according to claim 14.
The present invention provides a battery-operated stationary sensor arrangement with a
unidirectional data transmission. The battery-operated stationary sensor arrangement
comprises a sensor, a means for generating data packets and a for transmitting data
packets. The sensor is implemented to determine sensor data and to provide a sensor

data packet based on the sensor data, wherein the sensor data comprises an amount of
data of less than one kbit. The means for generating data packets is implemented to
divide the sensor data packet into at least two data packets, wherein each of the at least
two data packets is shorter than the sensor data packet. The means for transmitting data
packets is implemented to transmit the data packetsvia a communication channel with a
data rate of less than 50 kbit/s and a time interval.
In embodiments, the sensor data packet is divided into at least two data packets, wherein
the data packets are transmitted across the communication channel with a data rate of
less than 50 kbit/s and a time interval. As compared to a conventional battery-operated
stationary sensor arrangement wherein the sensor data packet is transmitted via the
communication channel with a data rate of e.g. 100 kbit/s, the SNR ratio (signal to noise
ratio) at the data receiver is increased and thus also the range is increased. Apart from
that, by dividing the sensor data packet into the at least two data packets and by the
transmission of the at least two data packets via the communication channel with a time
interval, on the one hand battery load and on the other hand transmission error probability
are reduced.
In the following, embodiments of the present invention are explained in more detail with
reference to the accompanying drawings, which:
Fig. 1 is a block diagram of a battery-operated stationary sensor arrangement
with a unidirectional data transmission according to one embodiment of the
present invention;
Fig. 2 is a block diagram of a system with a battery-operated stationary sensor
arrangement and a data receiver according to one embodiment of the
present invention;
Fig. 3 is a block diagram of a data receiver according to one embodiment of the
present invention;
Fig. 4 is a schematic illustration of a distribution of data packets to different
transmission frequencies according to one embodiment of the present
invention;

Fig. 5 is a time capacity utilization of a communication channel with the Aloha
method;
Fig. 6 in a diagram, different possibilities for increasing Eb/N0 in a transmission of
a telegram according to one embodiment of the present invention;
Fig. 7 a diagram of a probability of receiving a telegram as a function of a
normalized telegram length;
Fig. 8 a time capacity utilization of a communication channel in a transmission of
n data packets according to one embodiment of the present invention;
Fig. 9 a diagram of a probability of a telegram error depending on the number of
data packets for fN= 20, DΣx=0.2 and P(XFw)=2.3-10-10;
Fig. 10 a diagram of the probability of a telegram error depending on the
number of data packets for fN=20, DΣx=0.5 and P(XFw)=1.0.10-4;
and
Fig. 11 a diagram of the probability of a telegram error depending on the number of
data packets for fN= 20, DΣx=0.8 and P(XFw)=1.1.10-2.
In the following description of the embodiments of the invention, in the figures like or
seemingly like elements are provided with the same reference numerals, so that a
description of the same in the different embodiments is mutually interchangeable.
Fig. 1 shows a block diagram of a battery-operated stationary sensor arrangement 100
with a unidirectional data transmission. The battery-operated stationary sensor
arrangement 100 comprises a sensor 102, a means 104 for generating data packets and
a means 106 for transmitting data packets. The sensor 102 is implemented to determine
sensor data and to provide a sensor data packet based on the sensor data, wherein the
sensor data comprises an amount of data of less than 1 kbit. The means 104 for
generating data packets is implemented to divide the sensor data packet into at least two
data packets, wherein each of the at least two data packets is shorter than the sensor
data packet. The means 106 for transmitting data packets is implemented to transmit the

data packets with a data rate of less than 50 kbit/s and a time interval across a
communication channel.
In embodiments, for increasing the range, the sensor data is transmitted in a narrow-
banded way with a data rate of less than 50 kbit/s, e.g. 40 kbit/s, 30 kbit/s, 20 kbit/s or 10
kbit/s instead of, e.g., a data rate of 100 kbit/s. In a system 110 with a battery-operated,
stationary sensor arrangement 100 (data transmitter) with a unidirectional data
transmission (i.e. without reverse channel) and a data receiver 120, as e.g. illustrated in
Fig. 2, the SNR ratio at the data receiver 120 increases and thus also the range
increases. As a consequence, however, the bit duration increases and thus the
transmitted energy per bit increases in the inventive system 110 with the low data rate. As
the battery in the system 110 may not be put under load for a long time but may only
provide a higher power for a short time, the longer bit duration is a problem. In order to
guarantee a long battery lifetime only short bursts ought to be sent out. This is why the
narrow-banded sensor data packet is divided into smaller data packets (partial packets) in
order to only have a short pulse-type load of the battery. Further, the data packets may be
channel-coded, e.g. such that not all data packets but only a certain portion is required for
decoding the information.
The sensor 102 of the battery-operated stationary sensor arrangement 100 may be a
sensor or counter, like e.g. a temperature sensor, heating, current or water counter or
meter, wherein the sensor data may be a sensor value or counter reading. The inventive
system 110 with the battery-operated stationary sensor arrangement 100 (data
transmitter) and the data receiver 120 comprises no reverse channel. The data transmitter
100 may here send out the sensor data at a pseudorandom time, wherein the data
receiver 120 may receive sensor data from several (different) data transmitters 100.
Fig. 3 shows a block diagram of a data receiver 120 according to one embodiment of the
present invention. The data receiver 120 comprises a means 122 for receiving data
packets and a means 124 for reading out the sensor data packet. The means 122 for
receiving data packets is implemented to receive the at least two data packets and to
combine the at least two data packets in order to determine the sensor data packet. The
means 124 for reading out the sensor data packet is implemented to determine the sensor
data from the sensor data packet and to allocate the sensor data to the battery-operated
stationary sensor arrangement 100.

For the synchronization of the data packet in the data receiver 120 the means 104 for
generating data packets of the battery-operated stationary sensor arrangement 100 may
be implemented to divide a synchronization sequence into partial synchronization
sequences in order to provide each data packet with one of the partial synchronization
sequences.
The means 122 for receiving the data packets of the data receiver 120 may here be
implemented to localize the data packets in a received data stream based on the partial
synchronization sequences in order to receive the data packets.
For the synchronization of the data packets in the data receiver 120 thus synchronization
sequences may be utilized. Synchronization sequences are deterministic or
pseudorandom binary data sequences, e.g. PRBS sequences (pseudo random bitstream),
which are transmitted together with the actual payload data or sensor data in the data
packets to the data receiver 120. The data receiver 120 knows the synchronization
sequences. By a correlation of the receive data stream with the known synchronization
sequence the data receiver 120 may determine the temporal position of the known
synchronization sequence in the receive data stream. Here, the correlation function
comprises a correlation peak at the location of the synchronization sequence in the
receive data stream, wherein the higher or greater the peak the better the receive data
stream corresponds to the known synchronization sequence. To further keep the burst-
type data packets short, for a synchronization also the synchronization sequence may be
distributed across the individual short data packets, so that the individual data packet
shows worse synchronization characteristics than the synchronization across several data
packets. In order to utilize this synchronization effect, the points in time of the consecutive
data packets may be known to the data receiver 120. Alternatively, the means for
receiving the data packets of the data receiver 120 may be implemented to determine the
time interval or temporal distance of the data packets based on the partial synchronization
sequences in order to localize the partial synchronization sequence in the receive data
stream. As the data transmitter 100 and the data receiver 120 are stationary and thus
remain unchanged across a long period of time, the data receiver 120 may be
implemented to determine the time sequence of the data packets by learning methods.
The means 104 for generating data packets of the battery-operated stationary sensor
arrangement 100 may be implemented to additionally divide the sensor data packet into at
least three data packets, wherein each of the at least three data packets is shorter than

the sensor data packet. Further, the means 106 for transmitting data packets of the
battery-operated stationary sensor arrangement 100 may be implemented to transmit the
at least two data packets with a first transmit frequency across the communication
channel and to transmit the at least three data packets with a second transmit frequency
across the communication channel.
The means 122 for receiving the data packets of the data receiver 120 may here be
implemented to receive the at least two data packets on a first transmit frequency and/or
to receive the at least three data packets on the second transmit frequency and to
combine the at least two data packets and/or the at least three data packets in order to
determine the sensor data packet.
The means 104 for generating data packets of the battery-operated stationary sensor
arrangement 100 may further be implemented to encode the at least two data packets
with a first code rate (information rate) and to encode the at least three data packets with
a second code rate (information rate), wherein the first code rate is larger than the second
code rate.
In order to additionally be robust against interferences or existing or other systems, the
data packets may be distributed to different transmission frequencies or transmit
frequencies (channels). For example, the data packets may be distributed to n = 2, n = 3,
n = 4, n = 5, n = 10 or n = 20 channels.
Fig. 4 shows a schematic illustration of a distribution of data packets onto different
transmit frequencies according to one embodiment of the present invention. In Fig. 4, the
data packets are exemplarily divided into three transmit frequencies or frequency
channels. The telegram to be transmitted (sensor data packet) for example comprises an
amount of data of 75 bytes, wherein the data packets are for example transmitted with a
data rate of 20 kbit/s across the communication channel. The length of each data packet
here for example is 10 ms ( = 200 bits), from which an overall telegram length of 220 s
(update rate approximately 4 minutes) results.
In the embodiment illustrated in Fig. 4, the means 104 for generating data packets of the
battery-operated stationary sensor arrangement 100 is implemented to divide the sensor
data packet into 12 data packets in order to additionally divide the sensor data packet into
6 data packets and to additionally divide the sensor data packet into 4 data packets.

Further, the means 106 for transmitting the data packets of the battery-operated stationary
sensor arrangement 100 is implemented to transmit the 4 data packets on a first
transmission frequency (channel 1), the 6 data packets on a second transmission
frequency (channel 2) and the 12 data packets on a third transmission frequency (channel
3).
Further, the data in the individual channels may be encoded differently in order to be
optimal for different application scenarios. Thus, e.g. channel 3 may be encoded with a
rate of ¼ and data packets are more frequently transmitted on this channel than in
channel 1 by less frequently transmitting with a higher code rate of e.g. ¾. With
interferences in one or the other channel it would be possible to still decode the respective
other channel. In the non-interfered case, the data packets of all channels would be MLE
decoded (MLE = maximum likelihood estimation). In a rural environment where the
transmitter density is lower, using the code rate and the high packet transmission rate a
high range could be acquired. If the transmitter density increases, in this channel an
increase in collision and interferences results. With high transmitter densities in an urban
environment, the lower transmission rate in channel 1 would lead to less collisions but
also to a decreased range due to the higher code rate. With high transmitter densities,
however, no high range is required, as due to the many collisions a load-conditioned
range limitation results. Load-conditioned range limitation means that due to the occurring
collisions the stronger near data transmitters (better signal-to-noise ratio) are encoded
and the more remote weaker data transmitters are superimposed. It may be an advantage
in embodiments to transmit with a lower code rate with higher transmitter densities, even if
this results in a higher latency.
In the following, the improvements and advantages of the present invention as compared
to the prior art are explained in more detail.
Fig. 5 shows a temporal capacity utilization of a communication channel with the Aloha
method. Here, the abscissa describes the time and the ordinate describes the frequency.
In the Aloha method payload data is transmitted in so-called telegrams divided into one or
several data packets in one channel from a data transmitter. Further, in the same channel
n = 0 other data transmitters Xi, Xj and Xk, with i e {1,..,n}, j e {1,...,n} and kϵ {1,...,n} also
transmit data packets. If the transmission of one data packet of one data transmitter X
temporally overlaps sending out a data packet from data transmitter A, then as illustrated

in Fig. 5 the transmission of the data packet from the data transmitter A is interfered or
disturbed. Sending out data packets of the data transmitters C would happen randomly.
The length of the data packets of the data transmitter A is assumed to be TA, the one of
the data transmitters Xi is assumed to be Tx,i. The channel occupation of one individual
data transmitter Xi is defined by the so-called duty cycle of the respective data transmitter
Dx, = Τ /T ϵ [0,1] as a ratio of transmission time τ to operating time T. A data transmitter
may here take on the transmitter state S is on (1) or off (0), i.e. S e {0,1}. The probability
for an undisturbed transmission may be approximated to be

Here, DΣx = kDx is the sum duty cycle of the interfering or disturbing data transmitter X.
For receiving a transmission, at the data receiver 120 in principle a Eb/N0 depending on
the used modulation and channel encoding is required. Eb here designates the energy per
bit, No designates the noise performance density, the performance of noise in a
normalized bandwidth. The SNR ratio (signal to noise ratio) is defined as follows

with the signal energy S and the noise performance N. The noise performance (noise
power) here relates to a certain bandwidth, N = BN0 applies with the bandwidth B. The
signal performance is calculated to be S = EBD. Thus the following applies


with the data rate D. With an increasing distance of the data receiver 120 to the data
transmitter A, usually the received energy per bit Ebdecreases. In order to now increase
the range of a transmission, in principle different possibilities are available.
For example, transmission performance may be increased, whereby also the energy per
bit Eb is increased, which may not frequently be applied from a regulatory view. Further, a
modulation or channel encoding with a low Eb/N0 may be used, wherein this is limited by
the Shannon limit. Alternatively, the transmission duration of the telegram (sensor data
packet) may be increased, whereby the data rate is reduced and the energy per bit Eb is
increased which is the starting point described in the following.
In a diagram, Fig. 6 shows different possibilities for increasing Eb/N0 in a transmission of a
telegram (sensor data packet) according to one embodiment of the present invention.
Here, the abscissa describes the time and the ordinate describes the frequency. A
decrease of the data rate of the data transmitter A, as illustrated in Fig. 6, may be caused
by a lower symbol rate (transmitter B) or by the use of a lower code rate (transmitter C) or
a combination of both ways (transmitter D). By this, the required time for the transmission
is longer, and the data transmitter 100 may emit more energy with the same transmission
performance and a longer transmission time.
For example, the means for transmitting the data packets may be implemented to provide
the data packets with a symbol rate of less than 1106 symbol/s or also less than 5105
symbol/s, 3105 symbol/s, 2105 symbol/s or 1105 symbol/s and/or a code rate of less than
0.8 or also less than 0.5, 0.3, 0.25 or 0.1.
If a lower code rate is used, in general for a transmission a smaller Eb/N0 is required.
However, the required bandwidth increases as compared to the use of a slower
modulation. In all outlined cases, transmission is lengthened. In case of reducing the
symbol rate with

this leads to a reduction of the transmission probability.
Fig. 7 shows a diagram of a probability of receiving a telegram (sensor data packet) as a
function of a normalized telegram length. Here, the abscissa describes the normalized

telegram length fNW\\hfN = TA / Tx and the ordinate describes the probability P(A) of
receiving the telegram.
A first curve 150 describes the probability P(A) of receiving the telegram (sensor data
packet), for DΣx=0.05; a second curve 152 describes the probability P(A) of receiving
the telegram for DΣX = 0.10; a third curve 154 describes the probability P(A) of receiving
the telegram for DΣx =0.15 ; a fourth curve 156 describes the probability P(A) of receiving
the telegram for DΣx=0.20; and a fifth curve 158 describes the probability P(A) of
receiving the telegram for DΣx =0.30.
It may be seen in Fig. 7 that the probability P(A) of receiving the telegram (sensor data
packet) decreases with an increasing telegram length. Further, the probability P(A) of
receiving the telegram decreases with an increasing sum duty cycle DΣx . For increasing
the range, however, a lengthening of the transmission duration of the telegram (sensor
data packet) or a reduction of the data rate is required.
In embodiments, the sensor data packet is divided into at least two data packets, wherein
the data packets are transmitted with a data rate of less than 50 kbit/s and a time interval
or time distance across the communication channel. By dividing the sensor data packet
into the at least two data packets and by the transmission of the at least two data packets
via the communication channel with a time interval, on the one hand battery load and on
the other hand transmission error probability are reduced, as it is explained in the
following.
The telegram (sensor data packet), as for example illustrated in Fig. 8, may be transmitted
with the help of several n (of equal size) data packets. If an ideal code is assumed, at the
data receiver 120, when using the Code Rate c, at least data packets have to be
received error-free so that the telegram (sensor data packet) may be reconstructed error-
free. Here, using the packet error probability P(PF) the probability for a telegram error
P(TF) with p = \-P{PF) is calculated to be

For the following considerations it is assumed that the transmitted data packets were
transmitted at random times. It is further assumed in the following that a system X is
already in operation. The transmissionsare to be random, the amount of data is assumed

to be constant for all data transmitters of the system X, Tx is the transmission duration of
each data transmitter of the system X. DΣx is the summed up duty cycle of all data
transmitters of the system X.
Now a further data transmitter A is to be operated, wherein the data transmitter A relates
to the battery-operated stationary sensor arrangement 100. The data transmitter A is
disturbed by transmissions of the existing system X. The data transmitter A is to transmit
the same amount of data as in system X and use the same modulation.
The range of the data transmitter A with respect to the existing system X is to be
increased by increasing Eb by the factor fN. Thus, the transmission duration of the
telegram is lengthened by the factor fN. A telegram is transmitted divided into n individual
data packets. TT is the complete transmission duration of a telegram, TP = TT / n is the
transmission duration of a data packet. Thus, the following results for the packet error rate

According to this, the probability of a packet error increases with a higher fN and
decreases with a higher n, it is independent of the code rate c.
A data transmitter of the system X may transmit fN telegrams during the transmission time
which the data transmitter A requires for a telegram. By this, the probability increases that
a telegram of a transmitter X may be transmitted in the time in which the data transmitter
A transmits a telegram.
The probability for the data transmitter X with fN transmitted telegrams, each of which has
an error probability of P(XF), to receive none of them, like with the repetition code, is
calculated to be
P(XFw) = P(XF)f».
The bandwidth of the data transmitter A normalized to the data transmitters of system X is
calculated to be


Fig. 9 shows a diagram of a probability of a telegram error depending on the number of
data packets for fN=20, Dzx = 0.2 und P(XFW)=2.3-lO"10. A first curve 160 describes
the probability of a telegram error for c = 1 and bN = 0.05; a second curve 162 describes
the probability of a telegram error for c = 0.5 and bN = 0.1; a third curve 164 describes the
probability of a telegram error for c = 0.33 and bN = 0.15; a fourth curve 166 describes the
probability of a telegram error for c = 0.25 and bN = 0.20; a fifth curve 168 describes the
probability of a telegram error for c = 0.13 and bN = 0.4; and a sixth curve 170 describes
the packet error rate P(PF).
Fig. 10 shows a diagram of a probability of a telegram error depending on the number of
data packets for fN=20, Dzx=0.5 und P(XFW)=1.0-10"4. A first curve 172 describes
the probability of a telegram error for c = 1 and bN = 0.05; a second curve 174 describes
the probability of a telegram error for c = 0.5 and bN = 0.1; a third curve 176 describes the
probability of a telegram error for c = 0.33 and bN = 0.15; a fourth curve 178 describes the
probability of a telegram error for c = 0.25 and bN = 0.20; a fifth curve 180 describes the
probability of a telegram error for c = 0.13 and bN = 0.4; and a sixth curve 182 describes
the packet error rate P(PF).
Fig. 11 shows a diagram of a probability of a telegram error depending on the number of
data packets for fN =20, Dzx=0.S und P(XFw)=\.l-lO'2. A first curve 184 describes
the probability of a telegram error for c = 1 and bN = 0.05; a second curve 186 describes
the probability of a telegram error for c = 0.5 and bN = 0.1; a third curve 188 describes the
probability of a telegram error for c = 0.33 and bN = 0.15; a fourth curve 190 describes the
probability of a telegram error for c = 0.25 and bN = 0.20; a fifth curve 192 describes the
probability of a telegram error for c = 0.13 and bN = 0.4; and a sixth curve 194 describes
the packet error rate P(PF).
It may be seen in Figs. 9 to 11, that dividing the telegram (sensor data packet) into at least
two data packets protected by a forward error correction code increases the transmission
probability. This may also be considered under the aspect "time diversity". This is the
basis of the inventive concept to provide the telegram or sensor data packet with a
forward error correction and divide the same into at least two data packets and transmit
the same at pseudo random times. Here, the transmissions of the battery-operated
stationary sensor arrangement 100 are made longer (decreased data rate) in order to
increase the range. Using the outlined method the usually accompanying decrease of
transmission security is counteracted.

In embodiments, thus the range is increased by a more narrow-banded transmission and
additional channel encoding. Further, for improving transmission security (interference by
other systems) and for a decreased load of the battery the narrow banded sensor data
packets are divided into several short data packets. The data packets may additionally
also be transmitted on different frequency bands (frequency hopping). Apart from this, for
a better synchronization short synchronization sequences are used.
Further embodiments of the present invention provide a method for transmitting a sensor
data packet in a battery-operated stationary sensor arrangement with a unidirectional data
transmission. In a first step, sensor data is determined with a sensor and a sensor data
packet is provided based on the sensor data, wherein the sensor data comprises an
amount of data of less than 1 kbit. In a second step, data packets are generated, wherein
in the generation of data packets, the sensor data packet is divided into at least two data
packets and wherein each of the at least two data packets is larger than the sensor data
packet. In a third step, the at least two data packets are transmitted with a data rate of
less than 50 kbit/s and a time interval across a communication channel.
Further embodiments of the present invention relate to a wireless, unidirectional
transmission method for fields of application with a stationary data transmitter 100 and a
stationary data receiver 120, wherein the data receiver has a comparatively longer time to
receive the data.
Although some aspects were described in connection with a device, it is obvious that
those aspects also represent a description of the corresponding method, so that a block or
a member of a device may also be regarded as a corresponding method step or as a
feature of a method step. Analog to this, aspects which were described in connection with
or as a method step also represent a description of a corresponding block or detail or
feature of a corresponding device. Some or all of the method steps may be executed by a
hardware apparatus (or using a hardware apparatus), like, for example, a microprocessor,
a programmable computer or an electronic circuit. In some embodiments, some or several
of the most important method steps may be executed by such an apparatus.
Depending on certain implementation requirements, embodiments of the invention may be
implemented in hardware or in software. The implementation may be executed using a
digital storage medium, for example a floppy disc, a DVD, a Blu-Ray disc, a CD, an ROM,
a PROM, a EPROM, an EEPROM or a FLASH memory, a hard disc or another
magnetical or optical memory on which electronically readable control signals are stored
which may cooperate or do cooperate with a programmable computer system such that

the respective method is executed. Thus, the digital storage medium may be computer-
readable.
Some embodiments according to the invention thus include a data carrier which
comprises electronically readable control signals which are able to cooperate with a
programmable computer system such that one of the methods described herein is
executed.
In general, embodiments of the present invention may be implemented as a computer
program product with a program code, wherein the program code is operable in order to
execute one of the methods when the computer program product is executed on a
computer.
The program code may, for example, be stored on a machine-readable carrier.
Other embodiments include the computer program for executing one of the methods
described herein, wherein the computer program is stored on a machine-readable carrier.
In other words, an embodiment of the inventive method is thus a computer program
comprising a program code for executing one of the methods described herein when the
computer program is executed on a computer.
A further embodiment of the inventive method thus is a data carrier (or a digital storage
medium or a computer-readable medium) on which the computer program for executing
one of the methods described herein is recorded.
A further embodiment of the inventive method thus is a data stream or a sequence of
signals which, for example, represent the computer program for executing one of the
methods described herein. The data stream or the sequence of signals may, for example,
be configured so as to be transferred via a data communication connection, for example
via the internet.
A further embodiment includes a processing means, for example a computer or a
programmable logic device configured or adapted to execute one of the methods
described herein.
A further embodiment includes a computer on which the computer program for executing
one of the methods described herein is installed.

A further embodiment according to the invention includes a device or a system which is
implemented to transmit a computer program for executing at least one of the methods
described herein to a receiver. The transmission may be executed, for example,
electronically or optically. The receiver may, for example, be a computer, a mobile device,
a memory device or a similar device. The device or the system may, for example, be a file
server for transmitting the computer program to the receiver.
In some embodiments, a programmable logic device (for example a field programmable
gate array, an FPGA) may be used to execute some or all functionalities of the method
described herein. In some embodiments, a field-programmable gate array may cooperate
with a microprocessor in order to execute one of the methods described herein. In
general, in some embodiments the methods are executed by any hardware device. The
same may be a universally usable hardware like a computer processor (CPU) or hardware
which is specific for the method, like, for example, an ASIC.
The above described embodiments merely represent an illustration of the principles of the
present invention. It is obvious that modifications and variations of the arrangements and
details described herein are obvious to other persons skilled in the art. Thus, it is the
intention that the invention is only limited by the scope of the following patent claims and
not by the specific details presented by the description and the explanation of the
embodiments herein.

Claims
1. A battery-operated stationary sensor arrangement with a unidirectional data
transmission, comprising:
a sensor for determining sensor data and for providing a sensor data packet based
on the sensor data, the sensor data comprising an amount of data of less than
1 kbit;
a means for generating data packets which is implemented to divide the sensor
data packet into at least two data packets, wherein each of the at least two data
packets is shorter than the sensor data packet; and
a means for transmitting data packets which is implemented to transmit the data
packets with a data rate of less than 50 kbit/s and a time interval across the
communication channel,
wherein the means for generating data packets is implemented to divide a
synchronization sequence into partial synchronization sequences and to provide
each data packet with one of the partial synchronization sequences for a
synchronization of the data packet in a data receiver.
2. The battery-operated stationary sensor arrangement according to the preceding
claim, wherein the means for transmitting the data packets is implemented to
select the time interval of the data packets such that a battery load of the battery-
operated stationary sensor arrangement is reduced.
3. The battery-operated stationary sensor arrangement according to one of the
preceding claims, wherein the means for transmitting that data packets is
implemented to provide the data packets with a symbol rate of less than 106
symbols and/or a code rate of less than 0.8.

4. The battery-operated stationary sensor arrangement according to one of the
preceding claims, wherein the means for generating data packets is implemented
to divide the sensor data packet additionally into at least three data packets,
wherein each of the at least three data packets is shorter than the sensor data
packet; and
wherein the means for transmitting data packets is implemented to transmit the at
least two data packets with a first transmission frequency via the communication
channel and to transmit the at least three data packets with a second transmission
frequency via the communication channel.
5. The battery-operated stationary sensor arrangement according to claim 4, wherein
the means for generating data packets is implemented to encode the at least two
data packets with a first code rate and to encode the at least three data packets
with a second code rate, wherein the first code rate is higher than the second code
rate.
6. The battery-operated stationary sensor arrangement according to one of the
preceding claims, wherein the means for transmitting the data packets is
implemented to transmit the data packets with a data rate of less than 10 kbits/s.
7. A system having a battery-operated stationary sensor arrangement according to
one of the preceding claims and a data receiver for receiving the sensor data
packet, wherein the data receiver comprises:
a means for receiving data packets implemented to receive the at least two data
packets and to combine the at least two data packets and determine the sensor
data packet; and
a means for reading out the sensor data packet implemented to determine the
sensor data from the sensor data packet and to allocate the sensor data to the
battery-operated stationary sensor arrangement.

8. The system according to claim 7, wherein the at least two data packets each
comprise a partial synchronization sequence for the synchronization of the data
packet in the data receiver; and
wherein the means for receiving the data packets is implemented to localize the
data packets in a receive data stream based on the partial synchronization
sequences in order to receive the data packets.
9. The system according to claim 8, wherein the means for receiving the data packets
is implemented to determine the time interval of the data packets based on the
partial synchronization sequences to localize the partial synchronization
sequences in the receive data stream.
10. The system according to one of claims 7 to 9, wherein the sensor data packet
divided into at least two data packets is transmitted with a first transmission
frequency and, in addition, divided into at least three data packets is transmitted
with a second transmission frequency via the communication channel;
wherein the means for receiving the data packets is implemented to receive the at
least two data packets on a first transmission frequency and/or to receive the at
least three data packets on the second transmission frequency and to combine the
at least two data packets and/or the at least three data packets in order to
determine the sensor data packet.
11. The system according to claim 10, wherein the at least two data packets encoded
with a first code rate and the at least three data packets encoded with a second
code rate are transmitted via the communication channel;
wherein the means for receiving the data packets is implemented to decode the at
least two data packets and/or to decode the at least three data packets.
12. A method for transmitting a sensor data packet in a battery-operated stationary
sensor arrangement with a unidirectional data transmission, comprising:

determining sensor data with a sensor and providing a sensor data packet based
on the sensor data, wherein the sensor data comprises an amount of data of less
than 1 kbit;
generating data packets, wherein in the generation of data packets the sensor data
packet is divided into at least two data packets, and wherein each of the at least
two data packets is shorter than the sensor data packet; and
transmitting the at least two data packets with a data rate of less than 50 kbit/s and
a time interval via a communication channel,
wherein when generating data packets a synchronization sequence is divided into
partial synchronization sequences and each data packet is provided with one of
the partial synchronization sequences for a synchronization of the data packet in a
data receiver.
13. A computer program having a program code for executing the method according to
claim 12, when the computer program is executed on a computer or
microprocessor.
14. A battery-operated stationary sensor arrangement with unidirectional data
transmission, comprising:
a sensor for determining sensor data and for providing a sensor data packet based
on the sensor data, wherein the sensor data comprises an amount of data of less
than 1 kbit;
a means for generating data packets implemented to divide the sensor data packet
into at least three data packets, wherein each of the at least three data packets is
shorter than the sensor data packet; and
a means for transmitting data packets implemented to transmit the data packets
with a data rate of less than 50 kbit/s and a time interval via a communication
channel;

wherein the means for generating data packets is implemented to channel-encode
the at least three data packets such that only a part of the data packets is required
for decoding the sensor data packet.
15. A battery-operated stationary sensor arrangement with unidirectional data
transmission, comprising:
a sensor for determining sensor data and for providing a sensor data packet based
on the sensor data, wherein the sensor data comprises an amount of data of less
than 1 kbit;
a means for generating data packets implemented to divide the sensor data packet
into at least two data packets, each of the at least two data packets being shorter
than the sensor data packet; and
a means for transmitting data packets implemented to transmit the data packets
with a data rate of less than 50 kbit/s and a time interval via a communication
channel;
wherein the means for generating data packets is implemented to additionally
divide the sensor data packet into at least three data packets, each of the at least
three data packets being shorter than the sensor data packet; and
the means for transmitting data packets being implemented to transmit the at least
two data packets with a first transmission frequency via the communication
channel and to transmit the at least three data packets with a second transmission
frequency via the communication channel.