NO314680B1 - Communication unit and meter reading unit with dynamic geographical routing - Google Patents

Description

Technical area

The invention generally relates to radio communication systems, and more specifically to radio communication systems that use dynamic geographic routing to route messages through a network. In particular, the invention relates to a communication unit, a meter reading unit in which the communication unit is included and a telemetry network in which the meter reading unit is included.

Background for the invention

Reading consumption meters, such as electricity, water or gas consumption meters, has traditionally been done manually by a meter tester or by a customer. The recent development of the competitive situation within energy supplies has led to a need for more frequent and simplified procedures for reading such meters. Developments in smart home services and alarm services have also led to a need for communication systems for the transfer of data between buildings/households or between a building/household and a central unit. It is therefore desirable to produce a flexible and efficient communication unit which can form the basis for building such a communication system. In particular, it is desirable to produce a communication unit which enables dynamic geographic routing in a network. Such a communication unit can form part of a meter reading unit, where a larger number of such meter reading units form part of a telemetry network.

The position of the technique

A number of different systems for simplified and automated reading of consumption meters have previously been described.

EP-854 557 illustrates that it is previously known to retrofit equipment for optical reading of consumption meters for energy, after which reading data is transmitted to a central system, e.g. via the telephone network or via a radio transmission.

In US 5 874 903, a meter reading network formed by meter readers is described, where each reader comprises measuring equipment, a radio transceiver and a controller. Using the controller, each reader is further programmed to receive a message from another reader using the radio transceiver. Depending on the content of the message, the reader responds to the message by sending a modified message in a format that can be received by another reader in the network.

A disadvantage of this solution is that the network structure that the readers are part of is of a static nature. Nodes that would otherwise be difficult to reach from a main node can be reached by readers acting as repeater nodes. If a node drops out, or a node is added to the network, or if the sender-receiver conditions change drastically in areas covered by the network, the known system cannot be seen to enable any automatic, dynamic change of the routing of messages through the network.

Summary of the Invention

It is an aim of the present invention to provide a communication unit for use in a communication network such as a telemetry network, which does not have the above disadvantages.

Another purpose of the invention is to provide a meter reading unit for use in a meter reading network, which does not have the aforementioned disadvantages.

It is a further purpose of the invention to provide a telemetry network for communication between a server and meter readers, which does not have the aforementioned disadvantages.

The above purposes and other advantages are achieved by means of the features that appear in the subsequent, independent patent claims.

Further advantageous features appear from the non-independent requirements.

Brief description of the drawings

In the following, the invention will be described in more detail in the form of a preferred exemplary embodiment with reference to the drawings. Here shows:

fig. 1 a block diagram of a telemetry network in accordance with the invention,

fig. 2 is a block diagram of a meter reading unit in accordance with the invention,

fig. 3 is a block diagram of a server-connected meter reading unit in accordance with the invention,

fig. 4 is a block diagram of a server for use in a telemetry network in accordance with the invention.

Fig. 5 is an illustration of a process for selecting nodes when routing in a telemetry network in accordance with the invention.

Detailed description of the invention

Fig. 1 shows a block diagram for a telemetry network in accordance with the invention. A server 10 communicates via a connection 80 with a server-associated meter reading unit 100a. The connection 80 may comprise a fixed line such as an optical fiber connection, ISDN or analogue line, a mobile network such as GPRS, GSM/SMS, UMTS etc, a radio network or power line communication (Power

Line Communication, PLC).

The server 10 can optionally communicate with several server-connected meter reading units 100a via further connections 80 (not shown in Fig. 1).

Additional servers 10a, 10b may be arranged to communicate with the server 10 via high-speed connections 70.

The server-connected meter reading unit 100a in turn communicates via a radio-based connection 90 with one or more meter reading units 100. Each meter reading unit 100 is arranged to communicate via radio-based connections 90 with another one or more meter reading units 100.

Each meter reading unit 100, 100a is arranged for optical reading of a consumption meter, such as a meter board for recording consumed electrical energy. Each consumption meter can be contained in a meter board such as is linked to a residence or a building.

Each meter reading unit is designed to communicate with other meter reading units, and to thereby form a dynamically buildable communication network where different communication paths through the network can be established. Each individual meter reading unit does not need to communicate directly with the central server 10, nor directly with the radio access point, i.e. the server-linked meter reading unit 100a.

Fig. 2 shows a block diagram for a meter reading unit 100 in accordance with the invention.

The meter reading unit 100 comprises a reading unit 110 and a communication unit 120.

The read-in unit 110 is designed to provide input data to an input port on the microcontroller 132. For this purpose, the read-in unit 110 comprises in a preferred embodiment an optical sensor designed to image a series of numbers on an existing energy meter, and to transform the image into digital data.

The communication unit 120 comprises a control module 130 and a transceiver node 140.

The control module 130 comprises a microcontroller 132 with a program memory 136 and a data memory 138.

The program contained in the program memory 136 to be executed by the microcontroller 132 comprises a module for image processing, whereby image data read from the input unit 110 is transformed into numerical values, and a module for communication control which supports a communication protocol for communication between the communication unit 120 and another, corresponding communication unit 120 operating in the network.

The transceiver module 140 comprises a radio controller 142, a radio transceiver circuit 144 and an amplifier/antenna sharing circuit 146. The radio controller controls the transceiver circuit and comprises a memory that contains data about the radio communication's frequency, bandwidth, power, modulation etc. The transceiver circuit 144 contains a transmitter and a receiver, arranged for respectively to transmit and receive on a frequency and with a modulation specified by the radio controller 142.

The program stored in the program memory 136 to be executed by the microcontroller 132 further includes instructions to enable the meter reading unit 100 to communicate wirelessly with other meter reading units 100 using a packet based protocol. To achieve the routing in the network, a data packet, a so-called request message, is sent out, which contains information about the sender's identity and geographical position, the destination's identity and geographical position, as well as error correction codes. This information is processed by another, receiving meter reading unit 100 in the network to unload the package in the right way. This receiving meter reading unit calculates the distance it has to a straight line between sender and destination (kursawik data), and acknowledges by returning a response message that contains data about this distance, data about received signal strength and its own power level in addition to addresses and error codes ( confirmed/not confirmed). If the distance is greater than a fixed limit, no response message is returned.

The invention has, among other things, as a result of which the total transmission power is regulated to a minimum at all times, so that the least possible signal and noise is generated for other meter reading units 100 which are not participating at the moment.

Data about geographical position is stored in data memory 138 in the meter reading unit. This data can be obtained in different ways: 1. The fitter who installs the meter reading unit 100 is equipped with a control unit that has the same functionality as a radio access point, i.e. a server-linked meter reading unit 100a. This gives the fitter the opportunity to both program a meter reading unit 100 and to communicate with the meter reading unit, in particular to supply geographic measurement data, via the nodes (meter reading unit) in the area around the installation points. 2. The data can be obtained from the server 10, which has such data stored in its database 12 for meter data. If the serial number for the meter reading unit 100 is unique, it must then be made available to the server 10. This is particularly relevant in cases where the meter reading unit 100 has lost all or part of its short-term memory. 3. During the installation of a meter reading unit 100, the fitter uses a mobile terminal, e.g. a GPRS terminal. This terminal communicates directly with the server 10, which in turn will take care of the installation routines that the network uses. A message is generated and sent which, among other things, contains data for the geographical position of the newly installed meter reading unit 100. When the meter reading unit 100 has received its geographical position from the server 10, this information will be integrated into the protocol and used for communication later in the network. 4. During the installation, the fitter uses a GPS unit and a hand-held control unit (see all. 1) The geographical position data is conveyed to each meter reading unit 100 during installation, by the fitter reading the data from the GPS unit and transferring it to the meter reading unit 100 using of the handheld controller.

During transmission through the network, each meter reading unit 100 has also received data for the geographical position of the nearest server-connected meter reading unit 100a. This data is stored in the data memory 138 in the meter reading unit 100.

The meter reading unit 100 can further comprise additional signal inputs on the microcontroller 132 (not shown) for connection to external signal sources. Such inputs can e.g. used to transfer data related to weather conditions (signal from a barometer, a rainfall indicator, etc.), to alarm outputs (fire alarm, burglar alarm), to camera equipment for transmitting images in the event of a burglary, etc.

In particular, the meter reading unit 100 can comprise a temperature sensor (not shown), connected to a signal input on the microcontroller 132. Such a sensor can be used for detecting fire or fire outbreaks, and the network can be used for effective notification of this. Alternatively, another known per se sensor for smoke or gas formation can be used. Such a sensor placed integrated in the meter reading unit enables effective remote notification of fire/fire access without the installation of additional cables or components.

The meter reading unit 100 can further include signal outputs on the microcontroller 132 for connection to external control units. These outputs can be used to control external processes, for example providing control current to a contactor to switch a hot water tank on and off.

By means of further additional modules associated with the microcontroller 132, the meter reading unit 100 can be connected to other, external telecommunications and data communication equipment. This means that the meter reading unit 100 can be connected to various separate security systems, such as fire and burglar alarms, possibly control and/or measuring equipment linked to smart house solutions, etc. Fig. 3 shows a block diagram for a server-connected meter reading unit 100a in accordance with the invention. The server-associated meter reading unit 100a is essentially identical to the meter reading unit 100 discussed above with reference to fig. 2, but it additionally comprises a circuit 134 which allows direct communication with a server 10. The circuit 134 preferably comprises an interface to the telecommunications network, such as a fiber interface, alternatively, a GPRS interface, SMS interface, ISDN interface or an analogue modem for fixed line. Moreover, the program contained in the program memory 136 for executing the microcontroller 132 includes a module to support the communication with the server 10. Fig. 4 is a block diagram of a server for use in a communication system in accordance with the invention.

The server 10 is designed to ensure security and communication flow in the network. This is achieved by the server 10 and the individual meter reading unit 100 encrypting all useful data sent via the network and by the server 10 making continuous measurements that provide a basis for the network's status and traffic volume in a given period of time. These statistics are used to regulate parameters in the parts of the network that have the greatest traffic density, so that the distribution in time and area is as optimal as possible in relation to the network's capacity.

The meter reading units that are located closest to a server-connected meter reading unit 100 are exposed to a greater amount of traffic than those located elsewhere in the radio network, and it is in these areas that the regulation of parameters will yield the greatest benefit.

In addition, the server 10 performs all registration of data, logging of activities and service routines.

The server 10 comprises a processing unit 30 associated with a program memory 34 and a data memory 32. Furthermore, the server 10 comprises a database controller 16 and a radio network controller 18, both connected to the processing unit 30.

The database controller 16 is further connected to a database 12 for meter data. The database 12 stores and contains information obtained from each meter reader, such as meter reading, time of reading and state of the target unit 100.1 addition to this information, the geographical position of the meter unit 100 and series/measuring point/ facility number on which the meter unit 100 is located.

The database controller 16 is arranged to handle communication between the processing unit 30 and the database 12 for meter data. It is designed to act as a common interface to different database formats, and enables simple upgrading and/or expansion of the database 12,

The radio network controller 18 is also connected to a database 14 for radio network data. The radio network controller 18 is further connected to at least one radio access point controller 20. The radio access point controller 20 forms the link between the radio network controller 18 and each server-associated meter reading unit 100a. As illustrated in fig. 4, the individual radio access point controller 20 can be inside or outside the server 10.

The database 14 for radio networks contains logged information about all activity and all parameters set in the network. This information is used in a continuous process to regulate the dynamics and capacity of the radio network.

The radio network controller 18 is designed for operation of the entire radio network. In practice, this unit has the same functionality as an MSC (Mobile Service Switching Center) in GSM systems. This device has a logical block control that is logically independent of physical location.

The processing unit 20, the data memory 32 and the program memory 34 constitute an ordinary computer system such as a PC.

Fig. 5 illustrates how nodes are selected by dynamic routing in a telemetry network in accordance with the invention. In the following, a "node" in the network is understood as a communication unit 120 which is either part of a meter reading unit 100 or in a server-linked meter reading unit 100a.

In Figure 5, it is assumed that a node designated RECAPS-A is to be understood as a communication unit 120 in a meter reading unit 100. RECAPS-A is the sender node for a message, designated main message, which is to be sent to a destination node. The destination node is designated RECAPS-RAP, and is to be understood as a communication unit 120 in a server-connected meter reading unit 100a.

In an area between the sending mode RECAPS-A and the destination node RECAPS-RAP there are a number of intermediate nodes RECAPS-B, RECAPS-C, RECAPS-D, RECAPS-E. Each of these is a communication unit 120 in a meter reading unit 100.

The sender node RECAPS-A has stored data for an identification and the geographical position of the destination node RECAPS-RAP in its memory. This data is added to each node during installation.

The following steps 1-18 illustrate this process:

1. RECAPS-A verifies that the radio channel is free.

2. The sender node RECAPS-A broadcasts a request message on the radio if there is a node that can receive a message to RECAPS-RAP at a specific position. In the request message, the identification and position of RECAPS-A is stated. 3. Any node that intercepts the request message from the sending node RECAPS-A decodes the message and extracts data about the position of sender RECAPS-A and destination RECAPS-RAP. The node then calculates whether its own position lies within a minimum distance from the straight line between sender RECAPS-A and destination RECAPS-RAP. 4. If the node in question satisfies the distance condition, it will send a response message back to the sender RECAPS-A based on additional conditions regarding received radio signal strength and bit error rate for the received signal, as well as its own operational state in the network. The response message contains the node's identity and position, the signal strength at which it heard RECAPS-A, and the node's own status in the network. It also reports how many jumps it has made to the specified destination RECAPS-RAP, if it has compiled such information internally using the controller 132. As an alternative to the number of hops, the reply message can contain information about the distance from the node to the destination, calculated using the controller 132.

The response message is sent with a time delay that depends on the distance between the node and RECAPS-A. The greater the distance, the shorter the delay. This helps to avoid collisions between reply messages and to equalize the radio load in the network as a whole. 5. The sender node receives response messages from the relevant node and any other nodes that have sent a response message. The nodes that send a response message are considered current candidates to become the next node in the routing. The received response messages are decoded, and based on data extracted from the response message about the individual node's position, received radio signal level and received bit error rate, one of the nodes is selected as the next node in the routing. 6. RECAPS-A sends a main message to the node that has been selected in point 5. The other nodes that have sent a reply message and that also hear this message will go into standby mode. With reference to Figure 5, RECAPS-B will take responsibility for the main message and acknowledge back to RECAPS-A that it has received the main message. If the error rate is too high, RECAPS-B will ask for a new transmission of the message. 7. RECAPS-B is now responsible for forwarding the message towards the destination node RECAPS-RAP. The sender node RECAPS-A will retain its information about the message until the destination node RECAPS-RAP sends a received message to the sender node RECAPS-A. 8. When the node RECAPS-B has received a message to forward, it will start by verifying that the radio channel is free, and then it will broadcast a request message on the radio if there is anyone who can receive a message that going to RECAPS-RAP at a specific position. In this request message, RECAPS-B's identity and position is stated. The original sender identity and position of RECAPS-A will now be part of the message to be forwarded. 9. The sender node RECAPS-A will not respond to the request message sent in step 9, because its own identity or position matches the corresponding data in the sender address in the message. 10. With reference to fig. 5, the nodes RECAPS-C and RECAPS-D will respond to the request message sent in step 9. For each of these, if the node is to be able to respond, it must send a response message which, among other things, contains data representing the distance between the node's own position and the straight line between the sending node RECAPS-A and RECAPS-RAP. The response message also contains data on received radio signal strength, bit error rate, etc., similar to the response message described under point 4 above. 11. In this example, the three nodes RECAPS-C, RECAPS-E and RECAPS-D will report back to RECAPS-B that they can receive messages. RECAPS-D reports that it has 1 hop into RECAPS-RAP and has a good quality transmitter/receiver ratio. RECAPS-E reports back that it has 1 hop in, but has poor transceiver conditions. RECAPS-C reports that it has 2 hops in to RECAPS-RAP and has good transceiver conditions. 12. RECAPS-B receives response messages from RECAPS-C, RECAPS-E and RECAPS-D and decodes these messages. This results in, among other things, data on the individual node's position, received radio signal level and bit error rate on the node's received signal. On the basis of this data, RECAPS-B decides which node should be the next in the routing. In this example, RECAPS-D will be selected as the next node. 13. RECAPS-B sends the main message to RECAPS-D. RECAPS-D sends a receipt back to RECAPS-B and then takes responsibility for the main message to be sent to the destination RECAPS-RAP. 14. If the main message is to visit several nodes on its way to the destination node RECAPS-RAP, the routing function will be similar to that described in the points from 8 a.m. to 13. 15. In our example, RECAPS-RAP is the next node in the routing, and RECAPS-D will send a request message if there is someone who can forward the main message. RECAPS-RAP shall respond in the usual way with its own identity, position as well as data for received radio signal level and bit error rate, and if possible the number of hops to the destination node RECAPS-RAP (in this case the number is zero). 16. When RECAPS-D has forwarded the message, it will send a report message to WRC-B that the message has been forwarded, so that WRC-B can delete the main message with itself. 17. When RECAPS-RAP has received and approved the main message, it will give a message to the previous node in the routing (in the example: RECAPS-D) that the main message may have been deleted in the previous node. RECAPS-RAP is now responsible and may forward the message to server 10. 18. When RECAPS-RAP has received a receipt back from server 10, RECAPS-RAP will delete the main message with itself and send a receipt message stating that the transfer has been completed, back to the sending node RECAPS-A.

The dynamics of the resulting network is self-regulating, so that the routing will change if there are disturbances or changes in signal levels or physical obstacles to the signal. The packages can e.g. bypass an obstacle (large house, mountain) using this dynamic.

Professionals will, on the basis of the above, realize that a dynamic routing sequence from a server to a server-connected sender node to an arbitrary destination node in the network, or from an arbitrary, first sender node in the network to an arbitrary, second destination node in the network, can be achieved in a similar way.

Those skilled in the art will also recognize that there are obvious alternatives to a number of the detailed features exemplified in the description.

For example, the individual meter reading unit 100, 100a can be arranged to count pulses from the consumption meter, instead of reading a series of numbers. For this purpose, the read-in unit 110 is a simple adaptation circuit for received pulses, and the module for image processing in the program executed by the microcontroller 132 is replaced by a simple program module for counting pulses.

As an alternative to the connection 90 being radio-based, the connection 90 can be established using superposition of communication signal on a power line This can be particularly relevant in the event that a larger number of meter reading units 100 are located in places that have common power supply lines, such as in high-rise buildings or terraced houses.

Claims (16)

1. Communication device (120) for use in a communication network such as a telemetry network, comprising a radio transceiver (140) and a controller (130) with a memory (136, 138), where the controller (130) is arranged to - receive a request message from another communication unit (120) in the network by means of the transceiver (140) and - to decode the request message, characterized by that said memory (136, 138) contains - position data about the geographical position of the communication unit (120), that the controller is arranged to, when decoding the message, derive position data about a sender's geographical position and position data about a destination's geographical position, - that the controller is further arranged to, on the basis of this position data, calculate heading data representing the distance from the communication unit's own position to a right line between the sender's and the destination's positions, and - that the controller (130) is further arranged to send a response message which includes said course data back to said other communication unit (120) by means of the transceiver (140). 2. Communication unit (120) in accordance with claim 1, where said response message additionally comprises data representing a level for the radio signal received by the transceiver (140). 3. Communication unit (120) in accordance with one of claims 1-2, where said response message additionally comprises data representing a bit error rate for the radio signal received by the transceiver (140). 4. Communication unit (120) in accordance with one of claims 1-3, where the controller (130) is further arranged for to send said response message only if said course week data indicates that said distance is less than a given limit value. 5. Communication unit (120) in accordance with one of claims 1-4, where said reply message additionally includes data expressing the operational state of the communication unit (120) in the network. 6. Communication unit (120) in accordance with one of claims 1-5, where the controller is further arranged to send out said reply message after a time delay which is dependent on the position of the communication unit (120). 7. Communication unit (120) in accordance with claim 6, where the time delay also depends on the sender's geographical position. 8. Communication unit (120) in accordance with claim 7, where the time delay is greater the smaller the distance between the position of the communication unit (120) and the sender. 9. Communication unit (120) in accordance with one of claims 1-8, where the controller (130) is further arranged to - receive a response message from each of a number of communication units (120) in the network by means of the transceiver (140), - to decode the response messages, and - on the basis of data derived from the response messages, to determine which of communication unit one (120) to be selected as a recipient for a sent main message. 10. Meter reading unit (100) for use in a meter reading network, comprising a reading device (110) for reading values from a meter device, characterized in that it further comprises a communication unit (120) as stated in one of claims 1-9. 11. Meter reading unit (100) in accordance with claim 10, where the controller (130) is arranged to, by means of the transceiver (140), send a message containing data produced by the input device (110). 12. Meter reading unit (100) in accordance with one of claims 10-11, where the reading device (110) comprises an optical sensor arranged to image a series of numbers displayed on a meter, and where the controller (130) is arranged to transform optically read data into numerical values. 13. Meter reading unit (100a) in accordance with one of claims 10-12, further extensive equipment (134) for direct communication with an external server (10). 14. Meter reading unit (100) in accordance with one of claims 10-13, further comprising inputs to the controller 130 for reading in signals from a signal source. 15. Meter reading unit in accordance with claim 14, where the signal source is a temperature sensor contained in the meter reading unit. 16. Telemetry network, especially a meter reading network, characterized in that it comprises at least one server (10), at least one server-connected meter reading unit (100a) and at least one meter reading unit (100) in accordance with one of claims 10-15.