WO2016032379A1

WO2016032379A1 - Monitoring items using neighborhood-based network

Info

Publication number: WO2016032379A1
Application number: PCT/SE2014/050992
Authority: WO
Inventors: Gábor MAGYAR; Maxim TESLENKO; Jing Fu
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2014-08-28
Filing date: 2014-08-28
Publication date: 2016-03-03

Abstract

The proposed technology relates to methods and devices/nodes for monitoring items in physical vicinity of one another. For example, a method comprises forming (S1) a neighborhood-based network (3) comprising a plurality of items (2; 2a; 2b) to be monitored, where each item is provided with a respective communication device (10; 10a; 10b), and the neighborhood-based network (3) is based on a respective neighborhood of each respective communication device. The method further comprises checking (S2) the presence of each item within the neighborhood-based network. The forming (S1) and the checking (S2) are based on each communication device (10) broadcasting its own presence to other communication devices (10a; 10b) within its neighborhood, and each communication device (10) detecting other communication devices (10a; 10b) within its neighborhood. The method also comprises determining (S3) if an item is missing from the neighborhood-based network (3), based on each communication device (10) reporting to other communication devices (10a; 10b) within its neighborhood when a communication device is missing from its neighborhood, and when a communication device that has been reported as missing is detected in its neighborhood.

Description

MONITORING ITEMS USING NEIGHBORHOOD-BASED NETWORK

TECHNICAL FIELD The proposed technology generally relates to monitoring of items, and in particular to monitoring of items in physical vicinity of one another.

BACKGROUND In for example the transportation or warehouse industry, security of goods is a very important issue: Goods can be lost or stolen.

In a transportation case, vessels are usually carrying thousands of containers. It is a risk that some of these containers can be stolen. In addition, each container has maybe hundreds of goods inside, and hence it is also a risk that the integrity of a packed container gets harmed, e.g. something is stolen or lost from a container during the shipment.

There is a similar security problem e.g. in a warehouse where items are stored for a longer time. The overnight parking of a car fleet is another example of an industry area where such a security problem is relevant.

Basically in all cases when a set of objects/goods are staying/stored together at the same physical location for a relatively long period of time, and there is a risk that they can be stolen or lost, this type of security problem arises.

There is therefore a need to have a reliable security system that is capable of monitoring the presence of goods or other objects in their supposed location. The system should provide reliable and robust security and any object that is missing should be quickly recognized. SUMMARY

It is an object to provide a system, devices, methods and a computer program for monitoring items in physical vicinity of one another.

This and other objects are met by embodiments of the proposed technology.

An aspect of the embodiments relates to a method for monitoring items in physical vicinity of one another. The method comprises forming a neighborhood-based network comprising a plurality of items to be monitored, where each item of the plurality of items is provided with a respective communication device, and the neighborhood-based network is based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication device. The forming is based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The method further comprises checking the presence of each item of the plurality of items within the neighborhood-based network. The checking is based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication devices detecting other communication devices within its respective neighborhood. The method also comprises determining if an item is missing from the neighborhood- based network, where the determining is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

Another aspect of the embodiments relates to a method performed in a first communication device for supporting monitoring of items in physical vicinity of one another. The method comprises broadcasting the presence of the first communication device to other communication devices within a neighborhood of the first communication device, wherein the neighborhood comprises communication devices within communication range of the first communication device. The method further comprises detecting other communication devices within the neighborhood, and determining if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood. The method also comprises reporting, at least to other communication devices within the neighborhood, when a communication device is missing from the neighborhood, and when a communication device that has been reported as missing is detected in the neighborhood.

Yet another aspect of the embodiments relates to a method performed in a master node for supporting monitoring of items in physical vicinity of one another. The method comprises broadcasting the presence of the master node to communication devices within a neighborhood-based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device, and the neighborhood-based network is based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication device. The neighborhood-based network is formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The method further comprises receiving information representing the presence of items within the neighborhood-based network, and determining if an item is missing from the neighborhood-based network. The determining is based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood. Another aspect of the embodiments relates to a system configured to monitor items in physical vicinity of one another. The system comprises a neighborhood-based network comprising a plurality of items to be monitored, where each item of the plurality of items is provided with a respective communication device, and the neighborhood-based network is based on a respective neighborhood of each respective communication device, wherein each respective neighborhoods comprises communication devices within communication range of each respective communication device. The system is configured to form the neighborhood-based network based on each respective communication devices broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The system is further configured to check the presence of each item of the plurality of items within the neighborhood-based network, based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The system is also configured to determine if an item is missing from the neighborhood-based network, based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

Yet another aspect of the embodiments relates to a first communication device configured to support monitoring of items in physical vicinity of one another. The first communication device is configured to broadcast its presence to other communication devices within a neighborhood of the first communication device, wherein the neighborhood comprises communication devices within communication range of the first communication device. The first communication device is further configured to detect other communication devices within the neighborhood, and to determine if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood. The first communication device is also configured to report at least to other communication devices within the neighborhood when a communication device is missing from the neighborhood, and when a communication device that has been reported as missing is detected in the neighborhood. Yet another aspect of the embodiments relates to a computer program comprising instructions, which when executed by at least one processor, cause the processor or processors to prepare information representing the presence of a first communication device, for broadcasting to other communication devices within a neighborhood of the first communication device, wherein the neighborhood comprises communication devices within communication range of the first communication device, to read information regarding other communication devices detected within the neighborhood, to determine if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood, to prepare a report that a communication device is missing from the neighborhood, for sending at least to other communication devices within the neighborhood, and to prepare a report that a communication device that has been reported as missing is detected in the neighborhood, for sending at least to other communication devices within the neighborhood. Yet another aspect of the embodiments relates to a first communication device for supporting monitoring of items in physical vicinity of one another. The first communication device comprises a preparation module for preparing information representing the presence of the first communication device, for broadcasting to other communication devices within a neighborhood of the first communication device, wherein the neighborhood comprises communication devices within communication range of the first communication device. The first communication device further comprises a reading module for reading information regarding other communication devices detected within the neighborhood, and a determining module for determining if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood. The first communication device also comprises a report module for preparing a report that a communication device is missing from the neighborhood, for sending at least to other communication devices within the neighborhood, and for preparing a report that a communication device that has been reported as missing is detected in the neighborhood, for sending at least to other communication devices within the neighborhood. Yet another aspect of the embodiments relates to a master node configured to support monitoring of items in physical vicinity of one another. The master node is configured to broadcast the presence of the master node to communication devices within a neighborhood-based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device. The neighborhood-based network is based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication devices. The neighborhood-based network is formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication devices detecting other communication devices within its respective neighborhood. The master node is further configured to receive information representing the presence of items within the neighborhood-based network, and to determine if an item is missing from the neighborhood-based network, based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

Yet another aspect of the embodiments relates to a computer program comprising instructions, which when executed by at least one processor, cause the processor or processors to prepare information representing the presence of a master node, for broadcasting to communication devices within a neighborhood-based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device, the neighborhood-based network being based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication device, the neighborhood-based network being formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood, to read information representing the presence of items within the neighborhood-based network, and to determine if an item is missing from the neighborhood-based network, based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

Yet another aspect of the embodiments relates to a master node for supporting monitoring of items in physical vicinity of one another. The master node comprises a preparation module for preparing information representing the presence of the master node, for broadcasting to communication devices within a neighborhood- based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device, and the neighborhood-based network being based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication device. The neighborhood- based network is formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The master node further comprises a reading module for reading information representing the presence of items within the neighborhood-based network. The master node also comprises a determining module for determining if an item is missing from the neighborhood- based network, based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

An advantage of the proposed technology is that almost real-time monitoring of items can be achieved with simple and cheap sensors with small memory demands and a small amount of communication needed. The system is also robust and reliable due to the built-in redundancy of the system, with multiple neighbor reporting and distributed/local information processing.

Other advantages will be appreciated when reading the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which: Fig. 1 is a schematic illustration of an example of friendship relations between goods in a container.

Fig. 2 is a schematic flow diagram illustrating an example of a method for monitoring items in physical vicinity of one another according to an embodiment.

Fig. 3 is a schematic flow diagram illustrating an example of a method performed in a first communication device for supporting monitoring of items in physical vicinity of one another according to an embodiment. Fig. 4 is a schematic flow diagram illustrating optional additional steps of the method of Fig. 3. Fig. 5 is a schematic flow diagram illustrating further optional additional steps of the method of Fig. 3.

Fig. 6 is a schematic flow diagram illustrating a particular example implementation of the method of Fig. 3.

Fig. 7 is a schematic flow diagram illustrating an example of a method performed in a master node for supporting monitoring of items in physical vicinity of one another according to an embodiment.

Fig. 8 is a schematic flow diagram illustrating an optional additional step of the method of Fig. 7.

Fig. 9 is a schematic flow diagram illustrating further optional additional steps of the method of Fig. 7.

Fig. 10 is a schematic diagram illustrating an example of a system configured to monitor items in physical vicinity of one another according to an embodiment. Fig. 1 1 is a schematic block diagram illustrating an example of a communication device for supporting monitoring of items in physical vicinity of one another according to an embodiment.

Fig. 12 is a schematic block diagram illustrating an example of a master node for supporting monitoring of items in physical vicinity of one another according to an embodiment.

DETAILED DESCRIPTION Throughout the drawings, the same reference numbers are used for similar or corresponding elements. When using the word "comprise" or "comprising" it shall be interpreted as non- limiting, i.e. meaning "consist at least of".

For a better understanding of the proposed technology, it may be useful to begin with a brief overview of some background technology, described with reference to some non-limiting examples.

As described in the background section, there is a need for a reliable security system that is capable of monitoring the presence of goods or other objects in their supposed location. The system should provide reliable and robust security and any object that is missing should be quickly recognized. Real-time, or as least close to real-time, monitoring is therefore desirable. Robustness means that the security system should be safe subject to any kind of attacks or attempts to break into it. Existing solutions typically focus on each object to be secured one-by-one. There are several types of sensors and communication devices, e.g. Global Positioning Systems (GPS) based object monitoring, that are responsible for a given object's security. The problem of this solution is that once the security is broken (e.g. the GPS signals are hacked, etc.), the object will be unsecure and can be stolen.

In current solutions the monitored objects have to be periodically checked for presence. At each checking occasion information has to be transmitted from the object to the monitoring system which can trigger security alarms. If there is one central monitoring system it would imply that "long range" communication should be used to transmit data from the objects. That limits operation time of power constrained devices (objects). If the monitoring system is distributed it would require a potentially large number of distributed components (gateways) and as the result high complexity and cost of installation and operation of such systems. US 2008/0040244 A1 describes a system and method including a local network formed of a plurality of identification devices, each identification device in wireless communication with at least one other identification device. A gateway in wireless communication with the local network can allow direct or indirect communication between the gateway and each identification device in the local network. A central shipment controller can be configured to communicate with the gateway and is operable to receive data from and transmit data to the local network via the gateway. Thus, this document offers a method and system for forming clusters of objects in a hierarchical manner, i.e. a tree-structure, for asset tracking. The reporting of assets follows this the hierarchy. In this scheme every item is checked only once. The tree- structure is used to cascade information from low levels to the top, without redundancy. US 2010/0039284 A1 describes a method, a system and mobile sensor node for monitoring a supply chain. A communication network is established which includes a plurality of mobile sensor nodes. Status information for each mobile sensor node is periodically transmitted. Each mobile sensor node receives status information for at least one other mobile sensor node in the communication network. A log file which includes the received status information is compiled and stored in the mobile sensor node that received the corresponding status information. Each mobile sensor node then sends these log files to a central server for central processing and compilation. Identification of lost and stolen items is done in the central server. The present embodiments aim to provide a reliable security system that solves the problems described above by employing a set of communication devices attached to the items to be secured, where the items via the communication devices or communication nodes form a neighborhood-based network based on the neighborhood of each communication device. Resembling social networks, a "friendship" is established between two items if they are neighbors, so they are within communication range. During the security surveillance of the items, the presence of the supposed neighbors ("friends") is systematically checked and any missing item can be identified quickly, and almost real time. The distributed nature of the proposed security system makes it robust against attacks.

For easy understanding the system may be described in the context of a vessel- based cargo transportation industry. In such an environment the items to be monitored may for example be goods placed in a container. Fig. 1 is a schematic illustration of an example of friendship relations between the goods in a container. Boxes illustrate goods or items to be monitored, and a line between two boxes illustrates a friendship relation. The social network or neighborhood-based network 3 thus comprises items 2; 2a; 2b to be monitored connected through these friendship relations. For simplicity, few relations are shown in Fig. 1 , but in reality the number of relations could be much larger.

Fig. 2 is a schematic flow diagram illustrating an example of a method for monitoring items in physical vicinity of one another according to an embodiment. The method comprises the step S1 of forming a neighborhood-based network comprising a plurality of items to be monitored, where each item is provided with a respective communication device. The neighborhood-based network is based on a respective neighborhood of each communication device, where each respective neighborhood comprises communication devices within communication range of each respective communication device. The forming is based on each communication device broadcasting its own presence to other communication devices within its neighborhood, and each communication device detecting other communication devices within its neighborhood. The method further comprises the step S2 of checking the presence of each item of the plurality of items within the neighborhood- based network. The checking is based on each communication device broadcasting its own presence to other communication devices within its neighborhood, and each communication device detecting other communication devices within its neighborhood. The method also comprises the step S3 of determining if an item is missing from the neighborhood-based network. The determining is based on each communication device reporting at least to other communication devices within its neighborhood when a communication device is missing from its neighborhood, and when a communication device that has been reported as missing is detected in its neighborhood. In an embodiment, each of the respective communication devices is a short range communication device. Different embodiments may utilize any one of a number of wireless standards such as Bluetooth, Zigbee, 802.1 1 , or any other standards based on a wireless protocol, capable of transmitting data within a few meters to a few hundred meters.

In an embodiment the process of forming the social network or neighborhood-based network is based on a "self-forming" process, i.e. the friendship relations between the communication devices/nodes are established based on an auto-discovery process, where each communication device is learning its surrounding environment, i.e. all other communications devices/nodes within its neighborhood. Each device broadcasts its presence to the neighboring devices, and can then be detected by the neighboring devices. When devices are thus discovered in the neighborhood, each device may in one example embodiment store the discovered devices in a list. When monitoring the presence of the neighboring devices each device may then compare the currently detected devices with the stored list. Thus, in an example embodiment the step S1 of forming of a neighborhood-based network is further based on each respective communication device establishing a respective list of neighboring communication devices detected within its respective neighborhood. In such an example embodiment the step S3 of determining if an item is missing from the neighborhood-based network is further based on each respective communication device comparing detected communication devices within its respective neighborhood against its respective list of neighboring communication devices.

With the present embodiments, the items may be continuously monitored, almost in real-time. The monitoring can for example be done periodically by a given time interval. Thus, the step S2 of checking the presence of each item may in one embodiment be performed periodically by a determined time interval. The time interval may in one particular embodiment be of fixed length. In another particular embodiment time intervals of randomized lengths may be used, to make it more difficult to steal the items. In a particular embodiment the step S1 of forming the neighborhood-based network may be initiated by a master node. In such an example embodiment, each item that needs to be monitored gets a communication device attached. Then an auto- discovery process is taking place which is initiated by the master node. In the auto- discovery each device learns all other communication device in their neighborhood as well as the relay to the master node; the "friendship" relations are established. Each device will then have a list of the neighboring devices, as described above.

A master node may in one embodiment be of the same type of communication devices as all other nodes, since all nodes should communicate with each other (including the master node). A master node may in one embodiment have better antenna and signal amplifiers than the other communication devices, and thus a wider communication range. In the context of a vessel-based cargo transportation industry the items to be monitored may for example be goods placed in a container. The container may also have a communication device attached to it, and then the container may act as a master node. The container itself may in another hierarchy level serve as a single item among neighboring containers, where the captain cockpit may be the master node. An auto-discovery of neighboring containers may then be done at this level as well.

The initial setup phase may in one embodiment be activated/triggered by a master node (central server), which for example can be controlled by operational personnel. Once all goods are packed into the container, the container acts as the master node and activates this initial phase to let all items learn their neighbors. Also, in an alternative embodiment the ship's central node may start the initial setup phases when a ship leaves the harbour. When starting up the initial setup, a security mechanism using public key/private key pairs (see below) may in one embodiment be used to let devices known that the central server starting the initial setup is legitimate. In a particular embodiment the solution comprises three phases: initial setup, continuous monitoring as operational phase, and disassembly.

For disassembling the system, the master node will in one embodiment send a disassembly signal which makes all communication devices/nodes stop monitoring the presence of neighbors, and possibly switch to a power saving mode. In such an embodiment, disassembling needs to be made before a new initial setup can be made. Thus, if a communication device receives a new initial setup request while it is in monitoring phase, it rejects the request and sends a corresponding message to the master node.

In an alternative embodiment an initial setup phase is not required and all devices/nodes are constantly performing auto-discovery and continuous monitoring. As soon as the neighborhood is changed, a device may notify the master node. Thus, the master node in this embodiment continuously receives updates of the changes in neighborhood(s). This could for example be a case with cars in a parking lot, and cars arrive and leave. The master node gets notified whenever a car arrives to or leaves the parking lot. When receiving this notification, actions can be taken to check if the neighbor change is normal (a car leaves) or abnormal (a car is stolen). This checking may be done in a variety of ways, such as for example checking video cameras surveillance, or sending guards to check, or to check a credit card and/or passage card used to exit the parking lot, etc.

Some security considerations may be needed when using proposed scheme, so that a device cannot pretend to be another device, for example by sending out short range communication signals stating that it is still there. For example, a public- private key scheme may be used to achieve security.

Thus, in one embodiment secure communication is used within the neighborhood- based network, where the secure communication is based on each respective communication device broadcasting a respective public key to other communication devices within its respective neighborhood. The secure communication is also based on each respective communication device encrypting signals to other communication devices within its respective neighborhood with a respective private key, and each respective communication device decrypting signals from each respective other communication device within its respective neighborhood with a respective public key of each respective other communication device.

In an example embodiment, each communication device/node may have a public key that is broadcasted to its neighbors, for example during the initial setup. When monitoring other devices, each device encrypts the current time with its private key, and broadcasts it out using short range communication. When receiving these short range communication signals, a device needs to decrypt the message with the public key of the given device to be sure of the true identity of the device broadcasting. With this approach, it is hard to fake the presence of a device.

Fig. 3 is a schematic flow diagram illustrating an example of a method performed in a first communication device for supporting monitoring of items in physical vicinity of one another according to an embodiment. The method comprises the step S10 of broadcasting the presence of the first communication device to other communication devices within a neighborhood of the first communication device, wherein the neighborhood comprises communication devices within communication range of the first communication device. The method further comprises the step S20 of detecting other communication devices within the neighborhood, and the step S30 of determining if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood. The method also comprises the step S40 of reporting, at least to other communication devices within the neighborhood, when a communication device is missing from the neighborhood, and the step S50 of reporting, at least to other communication devices within the neighborhood, when a communication device that has been reported as missing is detected in the neighborhood. In an embodiment, the first communication device is a short range communication device. Different embodiments may utilize any one of a number of wireless standards such as Bluetooth, Zigbee, 802.1 1 , or any other standards based on a wireless protocol, capable of transmitting data within a few meters to a few hundred meters.

As described above, when a device discovers other devices in its neighborhood, it may in one example embodiment store the discovered devices in a list. When monitoring the presence of the neighboring devices the device may then compare the currently detected devices with the stored list. Fig. 4 is a schematic flow diagram illustrating such a particular embodiment of the method of Fig. 3. The method illustrated in Fig. 4 comprises the additional step S25 of adding detected communication devices within the neighborhood to a list of neighboring communication devices. The method illustrated in Fig. 4 also comprises the additional step S26 of comparing detected communication devices within the neighborhood against the list of neighboring communication devices. In this embodiment the step S30 of determining if a communication device is missing from the neighborhood is further based on the step S26 of comparing detected communication devices within the neighborhood against the list of neighboring communication devices. In one embodiment, the set of missing communication devices may be identified as the difference between list of neighboring communication devices and the detected communication devices within the neighborhood.

In a particular embodiment the step S10 of broadcasting the presence of the first communication device and the step S20 of detecting other communication devices are performed periodically by a determined time interval. The time interval may in one particular embodiment be of fixed length. In another particular embodiment time intervals of randomized lengths may be used, to make it more difficult to steal the items.

Fig. 5 is a schematic flow diagram illustrating further optional additional steps of the method of Fig. 3. In the embodiment of Fig. 5 secure communication is used within the neighborhood-based network, as described above. The method according to the embodiment of Fig. 5 further comprises a step S1 1 of broadcasting a public key to other communication devices within the neighborhood of the first communication device. In the embodiment of Fig. 5 the step S10 of broadcasting the presence of the first communication device, the step S40 of reporting when a communication device is missing and the step S50 of reporting when a communication device that has been reported as missing is detected further comprise a step S12 of encrypting signals to other communication devices within the neighborhood with a private key. Furthermore, in the embodiment of Fig. 5 the step S20 of detecting other communication devices within the neighborhood further comprises the step S13 of decrypting signals from each respective other communication device within the neighborhood with a respective public key of each respective other communication device.

Fig. 6 is a schematic flow diagram illustrating a particular example implementation of the method of Fig. 3. In the embodiment of Fig. 6 the same algorithm is operating in each communication device in a distributed manner. The master node or nodes in this embodiment may have special functionality to aggregate the signals coming from the set of communication devices.

Procedure running in each communication device at a given checking occasion: If a device does not see one of its supposed neighboring devices X for a specified time interval, it will send a broadcast alert message to all its neighbors and the master node (if it can be reached) containing the information 'device X is missing'. Then, the informed neighboring devices will check if device X is actually lost or not. The checking is done in two steps. First, if the device is a direct neighbor to device X from initial setup, it needs to check the recent short range communication with device X. Second, it also needs to check recent messages from its neighbors if device X is found. If device X has been seen, then the device broadcasts to its neighbors and the master node (if it can be reached) that 'device X is found'. Otherwise, if it also does not see the missing device X, then it further broadcasts this information to those of its neighbors that have not broadcasted 'device X is missing' yet. Finally, for each received message "X is found" the device re-broadcasts the message to all available neighbors that have not broadcasted 'device X is found' yet. In addition to the previously described communication signals regarding the presence of devices, the messages of 'device X is missing', 'device X is found' also need to be sent using secure communication, as described above. Thus, public- private keys can be used also to authenticate the devices when sending messages. This is to eliminate the possibility of a device falsely reporting the presence of another device.

Fig. 7 is a schematic flow diagram illustrating an example of a method performed in a master node for supporting monitoring of items in physical vicinity of one another according to an embodiment. The method comprises the step S100 of broadcasting the presence of the master node to communication devices within a neighborhood- based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device, and the neighborhood-based network is based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication device. The neighborhood-based network is formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The method further comprises the step S200 of receiving information representing the presence of items within the neighborhood- based network, and the step S300 of determining if an item is missing from the neighborhood-based network. The step S300 of determining is based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

Even though only a part of the communication devices/nodes could be in vicinity of the master node, and hence only this part of the nodes would "hear" a broadcast from the master node, the nodes will further re-broadcast information about the presence of the master node. This way all monitored nodes would finally receive a message broadcasted by the master node either directly from the master node or through re broadcast from the other nodes/devices. In an embodiment the information representing the presence of items within the neighborhood-based network received in step S200 comprises messages 'device X is missing' and/or 'device X is found'. A particular example implementation of the method of Fig. 7 can thus be described as follows: Once the master node receives (a series of) 'device X is missing' messages, and for a predefined time interval, no 'device X is found' message arrives, it alerts a missing item signal for device/item X. Otherwise, it discards the 'device X is missing' messages.

In a particular embodiment, the master node is a part of the neighborhood-based network, i.e. a part of a "mesh" which forwards messages between different communication devices.

As described above, the forming of the neighborhood-based network may be initiated by a master node. Accordingly, Fig. 8 is a schematic flow diagram illustrating an optional additional step of the method of Fig. 7. The method of Fig. 8 further comprises a step S400 of initiating the forming of the neighborhood-based network.

Communication between the master node and the communication devices may be protected using secure communication, for example by asymmetric encryption, similarly to what has been described above. Fig. 9 is a schematic flow diagram illustrating further optional additional steps of the method of Fig. 7. In the embodiment of Fig. 9 secure communication is used between the master node and the communication devices. The method according to the embodiment of Fig. 9 further comprises a step S101 of broadcasting a public key to the communication devices within the neighborhood-based network. All communication devices within the neighborhood-based network may not be within communication range of the master node. In the embodiment of Fig. 9 the step S100 of broadcasting the presence of the master node further comprises a step S102 of encrypting signals to communication devices within the neighborhood-based network with a private key. Furthermore, in the embodiment of Fig. 9 the step S200 of receiving information further comprises a step S103 of decrypting signals from each respective communication device within the neighborhood-based network with a respective public key of each respective communication device.

The master node may in an example embodiment share its public key during the initial setup phase. In a particular embodiment, a disassembly signal (see above) may also be encrypted with the private key of the master node which initiated the forming of the neighborhood-based network.

In an example of an implementation, at least some of the steps, functions, procedures, modules and/or blocks described herein are implemented in a computer program, which is loaded into a memory for execution by processing circuitry including one or more processors. The processor(s) and memory are interconnected to each other to enable normal software execution. An optional input/output device may also be interconnected to the processor(s) and/or the memory to enable input and/or output of relevant data such as input parameter(s) and/or resulting output parameter(s). The embodiments herein may thus be implemented through one or more processors, such as a processor 1 1 in the communication device 10 depicted in Fig. 10, or a processor 21 in the master node 20 depicted in Fig. 10, together with computer program code for performing the functions and actions of the embodiments herein.

According to an embodiment, a system 1 as illustrated in Fig. 10 is configured to monitor items in physical vicinity of one another. The system comprises a neighborhood-based network comprising a plurality of items to be monitored, where each item of the plurality of items is provided with a respective communication device 10; 10a; 10b, and the neighborhood-based network is based on a respective neighborhood of each respective communication device, wherein each respective neighborhoods comprises communication devices within communication range of each respective communication device. The system is configured to form the neighborhood-based network based on each respective communication devices broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The system is further configured to check the presence of each item of the plurality of items within the neighborhood-based network, based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The system is also configured to determine if an item is missing from the neighborhood-based network, based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

In an embodiment, each of the respective communication devices 10; 10a; 10b is a short range communication device. Different embodiments may utilize any one of a number of wireless standards such as Bluetooth, Zigbee, 802.1 1 , or any other standards based on a wireless protocol, capable of transmitting data within a few meters to a few hundred meters.

In an example embodiment the system 1 is further configured to form the neighborhood-based network based on each respective communication device establishing a respective list of neighboring communication devices detected within its respective neighborhood.

In such an example embodiment the system 1 is further configured to determine if an item is missing from the neighborhood-based network based on each respective communication device comparing detected communication devices within its respective neighborhood against its respective list of neighboring communication devices. In one embodiment the system 1 is configured to check the presence of each item periodically by a determined time interval. The time interval may in one particular embodiment be of fixed length. In another particular embodiment time intervals of randomized lengths may be used, to make it more difficult to steal the items.

In a particular embodiment the system 1 further comprises a master node 20 configured to initiate the forming of the neighborhood-based network.

In an embodiment the system 1 is further configured to use secure communication within the neighborhood-based network, where the secure communication is based on each respective communication device broadcasting a respective public key to other communication devices within its respective neighborhood. The secure communication is also based on each respective communication device encrypting signals to other communication devices within its respective neighborhood with a respective private key, and each respective communication device decrypting signals from each respective other communication device within its respective neighborhood with a respective public key of each respective other communication device. According to an embodiment, a first communication device 10 as illustrated in Fig. 10 is configured to support monitoring of items in physical vicinity of one another. The first communication device 10 is configured to broadcast its presence to other communication devices 10a; 10b within a neighborhood of the first communication device 10, wherein the neighborhood comprises communication devices within communication range of the first communication device 10. The first communication device 10 is further configured to detect other communication devices 10a; 10b within the neighborhood, and to determine if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood. The first communication device 10 is also configured to report at least to other communication devices within the neighborhood when a communication device is missing from the neighborhood, and when a communication device that has been reported as missing is detected in the neighborhood. In an example embodiment the first communication device 10 is further configured to add detected communication devices 10a; 10b within its neighborhood to a list of neighboring communication devices. In such an example embodiment the first communication device 10 is further configured to compare detected communication devices 10a; 10b within its neighborhood against the list of neighboring communication devices. In this embodiment the first communication device 10 is further configured to determine if a communication device is missing from its neighborhood based on this comparison.

In one embodiment the first communication device 10 is configured to broadcast its presence and detect other communication devices 10a; 10b periodically by a determined time interval. The time interval may in one particular embodiment be of fixed length. In another particular embodiment time intervals of randomized lengths may be used, to make it more difficult to steal the items.

In an embodiment the first communication device 10 is further configured to broadcast a public key to other communication devices 10a; 10b within its neighborhood. The first communication device 10 is also configured to encrypt signals to other communication devices 10a; 10b within its neighborhood with a private key, and to decrypt signals from each respective other communication device 10a; 10b within its neighborhood with a respective public key of each respective other communication device 10a; 10b. According to an embodiment, a master node 20 as illustrated in Fig. 10 is configured to support monitoring of items in physical vicinity of one another. The master node 20 is configured to broadcast its presence to communication devices within a neighborhood-based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device. The neighborhood-based network is based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication devices. The neighborhood-based network is formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication devices detecting other communication devices within its respective neighborhood. The master node is further configured to receive information representing the presence of items within the neighborhood-based network, and to determine if an item is missing from the neighborhood-based network, based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

In a particular embodiment, the master node 20 is part of the neighborhood-based network.

In another particular embodiment, the master node 20 is further configured to initiate forming of the neighborhood-based network. In an embodiment the master node 20 is further configured to broadcast a public key to the communication devices 10; 10a; 10b within the neighborhood-based network. The master node 20 is also configured to encrypt signals to communication devices 10; 10a; 10b within the neighborhood-based network with a private key, and to decrypt signals from each respective communication device 10; 10a; 10b within the neighborhood-based network with a respective public key of each respective communication device 10; 10a; 10b.

Fig. 10 is a schematic diagram illustrating an example of a system 1 operative to monitor items in physical vicinity of one another according to an embodiment. The system 1 comprises a first communication device 10 operative to support monitoring of items in physical vicinity of one another, other communication devices 10a; 10b within the neighborhood of the first communication device 10, and a master node 20 operative to support monitoring of items in physical vicinity of one another. In this example, the first communication device 10 basically comprises a processor 1 1 , an associated memory 12 and optional communication circuitry 13, and the master node 20 basically comprises a processor 21 , an associated memory 22 and optional communication circuitry 23. The optional communication circuitry 13, 23 is adapted for wireless communication with one or more other communication devices or nodes, including transmitting and/or receiving information.

As indicated in the specific example of Fig. 10, the first communication device 10 comprises a processor 1 1 and a memory 12, wherein the memory 12 comprises instructions executable by the processor 1 1 to perform operations of the first communication device 10. Thus, in this example embodiment the processor 1 1 is operative to determine if a communication device is missing from the neighborhood of the first communication device, based on detected communication devices 10a; 10b within the neighborhood.

In a particular embodiment of the first communication device 10 the processor 1 1 is further operative to encrypt signals to other communication devices 10a; 10b within the neighborhood with a private key; and to decrypt signals from each respective other communication device 10a; 10b within the neighborhood with a respective public key of each respective other communication device 10a; 10b.

As indicated in the specific example of Fig. 10, the master node 20 comprises a processor 21 and a memory 22, wherein the memory 22 comprises instructions executable by the processor 21 to perform operations of the master node 20. Thus, in this example embodiment the processor 21 is operative to determine if an item is missing from the neighborhood-based network, based on received information representing the presence of items within the neighborhood-based network.

In a particular embodiment of the master node 20 the processor 21 is further operative to initiate forming of the neighborhood-based network.

As indicated in the specific example of Fig. 10, the first communication device 10 may also include communication circuitry 13 for communication with one or more other communication devices/nodes, including transmitting and/or receiving information. Thus, in this example embodiment the first communication device 10 comprises communication circuitry 13 configured to broadcast the presence of the first communication device 10 to other communication devices 10a; 10b within the neighborhood, to detect other communication devices 10a; 10b within the neighborhood, to send a report at least to other communication devices 10a; 10b within the neighborhood when a communication device is missing from the neighborhood, and to send a report at least to other communication devices 10a; 10b within the neighborhood when a communication device that has been reported as missing is detected in the neighborhood.

In a particular embodiment of the first communication device 10 the communication circuitry 13 is further configured to broadcast a public key to other communication devices 10a; 10b within the neighborhood.

As indicated in the specific example of Fig. 10, the master node 20 may also include communication circuitry 23 for communication with one or more communication devices/nodes, including transmitting and/or receiving information. Thus, in this example embodiment the master node 20 comprises communication circuitry 23 configured to broadcast the presence of the master node 20 to communication devices 10; 10a; 10b within the neighborhood-based network, and to receive information representing the presence of items within the neighborhood-based network. In a particular embodiment of the master node 20 the communication circuitry 23 is further configured to broadcast a public key to the communication devices 10; 10a; 10b within the neighborhood-based network.

As described above, at least some of the steps, functions, procedures, modules and/or blocks described above may be implemented in software such as a computer program for execution by suitable processing circuitry including one or more processing units. According to an embodiment, a computer program comprises instructions, which when executed by at least one processor, cause the processor(s) to prepare information representing the presence of a first communication device, for broadcasting to other communication devices within a neighborhood of the first communication device, wherein the neighborhood comprises communication devices within communication range of the first communication device, to read information regarding other communication devices detected within the neighborhood, to determine if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood, to prepare a report that a communication device is missing from the neighborhood, for sending at least to other communication devices within the neighborhood, and to prepare a report that a communication device that has been reported as missing is detected in the neighborhood, for sending at least to other communication devices within the neighborhood.

According to another embodiment, a computer program comprises instructions, which when executed by at least one processor, cause the processor(s) to prepare information representing the presence of a master node, for broadcasting to communication devices within a neighborhood-based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device, the neighborhood-based network being based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication device, the neighborhood-based network being formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood, to read information representing the presence of items within the neighborhood-based network, and to determine if an item is missing from the neighborhood-based network, based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood. The proposed technology also provides one or more carriers comprising one or more of the above computer programs, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium. By way of example, the software or computer program may be realized as a computer program product, which is normally carried or stored on a computer-readable medium, in particular a non-volatile medium. The computer-readable medium may include one or more removable or non-removable memory devices including, but not limited to a Read-Only Memory (ROM), a Random Access Memory (RAM), a Compact Disc (CD), a Digital Versatile Disc (DVD), a Blueray disc, a Universal Serial Bus (USB) memory, a Hard Disk Drive (HDD) storage device, a flash memory, a magnetic tape, or any other conventional memory device. The computer program may thus be loaded into the operating memory of a computer or equivalent processing device for execution by the processing circuitry thereof.

The flow diagram or diagrams presented above may be regarded as a computer flow diagram or diagrams, when performed by one or more processors. A corresponding communication device or node may be defined as a group of function modules, where each step performed by the processor(s) corresponds to a function module. In this case, the function modules are implemented as a computer program running on the processor(s). Hence, the first communication device and/or the master node may alternatively be defined as a group of function modules, where the function modules are implemented as a computer program running on at least one processor. Hence, a computer program residing in memory may be organized as appropriate function modules configured to perform, when executed by the processor(s), at least part of the steps and/or tasks described herein. Examples of such function modules are illustrated in Fig. 1 1 and Fig. 12. Fig. 1 1 is a schematic block diagram illustrating an example of a first communication device 10 for supporting monitoring of items in physical vicinity of one another. The first communication device 10 in this example comprises a preparation module 100 for preparing information representing the presence of the first communication device, for broadcasting to other communication devices within a neighborhood of the first communication device, wherein the neighborhood comprises communication devices within communication range of the first communication device. The first communication device further comprises a reading module 200 for reading information regarding other communication devices detected within the neighborhood, and a determining module 300 for determining if a communication device is missing from the neighborhood, based on detected communication devices within the neighborhood. The first communication device also comprises a report module 400 for preparing a report that a communication device is missing from the neighborhood, for sending at least to other communication devices within the neighborhood, and for preparing a report that a communication device that has been reported as missing is detected in the neighborhood, for sending at least to other communication devices within the neighborhood. Fig. 12 is a schematic block diagram illustrating an example of a master node 20 for supporting monitoring of items in physical vicinity of one another. The master node 20 in this example comprises a preparation module 120 for preparing information representing the presence of the master node, for broadcasting to communication devices within a neighborhood-based network, where the neighborhood-based network comprises a plurality of items to be monitored, each item of the plurality of items being provided with a respective communication device, and the neighborhood-based network being based on a respective neighborhood of each respective communication device, wherein each respective neighborhood comprises communication devices within communication range of each respective communication device. The neighborhood-based network is formed based on each respective communication device broadcasting its own presence to other communication devices within its respective neighborhood, and each respective communication device detecting other communication devices within its respective neighborhood. The master node further comprises a reading module 220 for reading information representing the presence of items within the neighborhood-based network. The master node also comprises a determining module 320 for determining if an item is missing from the neighborhood-based network, based on the received information, wherein the received information is based on each respective communication device reporting at least to other communication devices within its respective neighborhood when a communication device is missing from its respective neighborhood, and when a communication device that has been reported as missing is detected in its respective neighborhood.

An advantage of the proposed technology is that almost real-time monitoring of items can be achieved with simple and cheap sensors with small memory demands and a small amount of communication needed. The system is also robust and reliable due to the built-in redundancy of the system, with multiple neighbor reporting and distributed/local information processing in each communication node.

As used herein, the terms "communication device" and "communication node" should be interpreted as a non-limiting term comprising any type of wireless device communicating with other wireless communication devices or any device equipped with radio circuitry for wireless communication according to any relevant standard for wireless communication within a wireless communication system.

As used herein, the term "master node" should be interpreted as a non-limiting term comprising any type of wireless device communicating with other wireless communication devices or any device equipped with radio circuitry for wireless communication according to any relevant standard for wireless communication within a wireless communication system, with additional functionality for processing information received from other wireless communication devices within that wireless communication system.

It will be appreciated that the methods and devices described herein can be combined and re-arranged in a variety of ways. For example, embodiments may be implemented in hardware, or in software for execution by suitable processing circuitry, or a combination thereof.

The steps, functions, procedures, modules and/or blocks described herein may be implemented in hardware using any conventional technology, such as discrete circuit or integrated circuit technology, including both general-purpose electronic circuitry and application-specific circuitry.

Particular examples include one or more suitably configured digital signal processors and other known electronic circuits, e.g. discrete logic gates interconnected to perform a specialized function, or Application Specific Integrated Circuits (ASICs).

Examples of processing circuitry includes, but is not limited to, one or more microprocessors, one or more Digital Signal Processors, DSPs, one or more Central Processing Units, CPUs, video acceleration hardware, and/or any suitable programmable logic circuitry such as one or more Field Programmable Gate Arrays, FPGAs, or one or more Programmable Logic Controllers, PLCs.

It should also be understood that it may be possible to re-use the general processing capabilities of any conventional device or unit in which the proposed technology is implemented. It may also be possible to re-use existing software, e.g. by reprogramming of the existing software or by adding new software components.

The term 'processor' should be interpreted in a general sense as any system or device capable of executing program code or computer program instructions to perform a particular processing, determining or computing task.

The processing circuitry including one or more processors is thus configured to perform, when executing the computer program, well-defined processing tasks such as those described above.

The processing circuitry does not have to be dedicated to only execute the above- described steps, functions, procedure and/or blocks, but may also execute other tasks. The embodiments described above are merely given as examples, and it should be understood that the proposed technology is not limited thereto. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the present scope as defined by the appended claims. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible.

Claims

1 . A method for monitoring items in physical vicinity of one another, wherein said method comprises:

forming (S1 ) a neighborhood-based network (3) comprising a plurality of items

(2; 2a; 2b) to be monitored, each item of said plurality of items being provided with a respective communication device (10; 10a; 10b), said neighborhood-based network (3) being based on a respective neighborhood of each of said respective communication devices (10; 10a; 10b), wherein each of said respective neighborhoods comprises communication devices (10a; 10b) within communication range of each of said respective communication devices (10), said forming (S1 ) being based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood;

checking (S2) the presence of each item of said plurality of items (2; 2a; 2b) within said neighborhood-based network (3), said checking (S2) being based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood; and

determining (S3) if an item is missing from said neighborhood-based network (3), said determining (S3) being based on each of said respective communication devices (10) reporting at least to other communication devices (10a; 10b) within its respective neighborhood

when a communication device is missing from its respective neighborhood, and

when a communication device that has been reported as missing is detected in its respective neighborhood.

2. The method according to claim 1 , wherein each of said respective communication devices (10; 10a; 10b) is a short range communication device.

3. The method according to claim 1 or 2, wherein said forming (S1 ) a neighborhood- based network (3) is further based on each of said respective communication devices (10; 10a; 10b) establishing a respective list of neighboring communication devices detected within its respective neighborhood.

4. The method according to claim 3, wherein said determining (S3) if an item is missing from said neighborhood-based network (3) is further based on each of said respective communication devices (10; 10a; 10b) comparing detected communication devices within its respective neighborhood against said respective list of neighboring communication devices.

5. The method according to any of the claims 1 to 4, wherein said checking (S2) the presence of each item is performed periodically by a determined time interval.

6. The method according to any of the claims 1 to 5, wherein said forming (S1 ) a neighborhood-based network (3) is initiated by a master node (20).

7. The method according to any of the claims 1 to 6, wherein said method is performed using secure communication within said neighborhood-based network (3), said secure communication being based on

each of said respective communication devices (10) broadcasting a respective public key to other communication devices (10a; 10b) within its respective neighborhood;

each of said respective communication devices (10) encrypting signals to other communication devices (10a; 10b) within its respective neighborhood with a respective private key; and

each of said respective communication devices (10) decrypting signals from each respective other communication device (10a; 10b) within its respective neighborhood with a respective public key of each of said respective other communication devices (10a; 10b).

8. A method performed in a first communication device (10) for supporting monitoring of items in physical vicinity of one another, wherein said method comprises:

broadcasting (S10) the presence of said first communication device (10) to other communication devices (10a; 10b) within a neighborhood of said first communication device (10), wherein said neighborhood comprises communication devices within communication range of said first communication device (10);

detecting (S20) other communication devices (10a; 10b) within said neighborhood;

determining (S30) if a communication device is missing from said neighborhood, based on detected communication devices (10a; 10b) within said neighborhood;

reporting (S40), at least to other communication devices (10a; 10b) within said neighborhood, when a communication device is missing from said neighborhood; and

reporting (S50), at least to other communication devices (10a; 10b) within said neighborhood, when a communication device that has been reported as missing is detected in said neighborhood.

9. The method according to claim 8, wherein said first communication device (10) is a short range communication device.

10. The method according to claim 8 or 9, further comprising adding (S25) detected communication devices (10a; 10b) within said neighborhood to a list of neighboring communication devices.

1 1 . The method according to claim 10, further comprising comparing (S26) detected communication devices (10a; 10b) within said neighborhood against said list of neighboring communication devices, wherein said determining (S30) if a communication device is missing from said neighborhood is further based on said comparing (S26).

12. The method according to any of the claims 8 to 1 1 , wherein said broadcasting (S10) the presence of said first communication device (10) and said detecting (S20) other communication devices (10a; 10b) are performed periodically by a determined time interval.

5

13. The method according to any of the claims 8 to 12, wherein said method further comprises:

broadcasting (S1 1 ) a public key to other communication devices (10a; 10b) within said neighborhood,

10 wherein said broadcasting (S10) the presence of said first communication device (10), said reporting (S40) when a communication device is missing and said reporting (S50) when a communication device that has been reported as missing is detected further comprise encrypting (S12) signals to other communication devices (10a; 10b) within said neighborhood with a private key; and

15 wherein said detecting (S20) other communication devices (10a; 10b) within said neighborhood further comprises decrypting (S13) signals from each respective other communication device (10a; 10b) within said neighborhood with a respective public key of each of said respective other communication devices (10a; 10b).

20 14. A method performed in a master node (20) for supporting monitoring of items in physical vicinity of one another, wherein said method comprises:

broadcasting (S100) the presence of said master node (20) to communication devices (10; 10a; 10b) within a neighborhood-based network (3), said neighborhood- based network (3) comprising a plurality of items (2; 2a; 2b) to be monitored, each

25 item of said plurality of items (2; 2a; 2b) being provided with a respective communication device (10; 10a; 10b), said neighborhood-based network (3) being based on a respective neighborhood of each of said respective communication devices (10; 10a; 10b), wherein each of said respective neighborhoods comprises communication devices (10a; 10b) within communication range of each of said

30 respective communication devices (10), said neighborhood-based network (3) being formed based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood;

receiving (S200) information representing the presence of items (2; 2a; 2b) within said neighborhood-based network (3); and

5 determining (S300) if an item is missing from said neighborhood-based network (3), said determining (S300) being based on said received information, wherein said received information is based on each of said respective communication devices (10) reporting at least to other communication devices (10a; 10b) within its respective neighborhood

10 when a communication device is missing from its respective neighborhood, and

15 15. The method according to claim 14, wherein each of said respective communication devices (10; 10a; 10b) is a short range communication device.

16. The method according to claim 14 or 15, wherein said master node (20) is a part of said neighborhood-based network (3).

20

17. The method according to any of the claims 14 to 16, wherein said method further comprises initiating (S400) forming of said neighborhood-based network (3).

18. The method according to any of the claims 14 to 17, wherein said method further 25 comprises:

broadcasting (S101 ) a public key to said communication devices (10; 10a; 10b) within said neighborhood-based network (3),

wherein said broadcasting (S100) the presence of said master node (20) further comprises encrypting (S102) signals to communication devices (10; 10a; 30 10b) within said neighborhood-based network (3) with a private key; and

wherein said receiving (S200) information further comprises decrypting (S103) signals from each respective communication device (10; 10a; 10b) within said neighborhood-based network (3) with a respective public key of each of said respective communication devices (10; 10a; 10b).

19. A system (1 ) configured to monitor items in physical vicinity of one another,

wherein the system (1 ) comprises a neighborhood-based network (3) comprising a plurality of items (2; 2a; 2b) to be monitored, each item of said plurality of items being provided with a respective communication device (10; 10a; 10b), said neighborhood-based network (3) being based on a respective neighborhood of each of said respective communication devices (10; 10a; 10b), wherein each of said respective neighborhoods comprises communication devices (10a; 10b) within communication range of each of said respective communication devices (10),

wherein the system (1 ) is configured to form said neighborhood-based network (3) based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood,

wherein the system (1 ) is configured to check the presence of each item of said plurality of items (2; 2a; 2b) within said neighborhood-based network (3), based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood; and

wherein the system (1 ) is configured to determine if an item is missing from said neighborhood-based network (3), based on each of said respective communication devices (10) reporting at least to other communication devices (10a; 10b) within its respective neighborhood

when a communication device is missing from its respective neighborhood, and

20. The system (1 ) according to claim 19, wherein each of said respective communication devices (10; 10a; 10b) is a short range communication device

21 . The system (1 ) according to claim 19 or 20, wherein the system is further 5 configured to form said neighborhood-based network (3) based on each of said respective communication devices (10; 10a; 10b) establishing a respective list of neighboring communication devices detected within its respective neighborhood.

22. The system (1 ) according to claim 21 , wherein the system is further configured to 10 determine if an item is missing from said neighborhood-based network (3) based on each of said respective communication devices (10; 10a; 10b) comparing detected communication devices within its respective neighborhood against said respective list of neighboring communication devices.

15 23. The system (1 ) according to any of the claims 19 to 22, wherein the system is configured to check the presence of each item periodically by a determined time interval.

24. The system (1 ) according to any of the claims 19 to 23, wherein the system 20 further comprises a master node (20) configured to initiate forming of said neighborhood-based network (3).

25. The system (1 ) according to any of the claims 19 to 24, wherein the system is further configured use secure communication within said neighborhood-based

25 network (3), said secure communication being based on

each of said respective communication devices (10) encrypting signals to 30 other communication devices (10a; 10b) within its respective neighborhood with a respective private key; and

26. A first communication device (10) configured to support monitoring of items in physical vicinity of one another,

wherein the first communication device (10) is configured to broadcast its presence to other communication devices (10a; 10b) within a neighborhood of said first communication device (10), wherein said neighborhood comprises communication devices within communication range of said first communication device (10);

wherein the first communication device (10) is configured to detect other communication devices (10a; 10b) within said neighborhood;

wherein the first communication device (10) is configured to determine if a communication device is missing from said neighborhood, based on detected communication devices (10a; 10b) within said neighborhood;

wherein the first communication device (10) is configured to report at least to other communication devices (10a; 10b) within said neighborhood when a communication device is missing from said neighborhood; and

wherein the first communication device (10) is configured to report at least to other communication devices (10a; 10b) within said neighborhood when a communication device that has been reported as missing is detected in said neighborhood.

27. The first communication device (10) according to claim 26, wherein the first communication device (10) is a short range communication device.

28. The first communication device (10) according to claim 26 or 27, wherein the first communication device (10) is further configured to add detected communication devices (10a; 10b) within said neighborhood to a list of neighboring communication devices.

29. The first communication device (10) according to claim 28, wherein the first communication device (10) is further configured to compare detected communication devices (10a; 10b) within said neighborhood against said list of neighboring communication devices, and

wherein the first communication device (10) is further configured to determine if a communication device is missing from said neighborhood based on said comparison.

30. The first communication device (10) according to any of the claims 26 to 29, wherein the first communication device (10) is configured to broadcast the presence of said first communication device (10) and detect other communication devices (10a; 10b) periodically by a determined time interval.

31 . The first communication device (10) according to any of the claims 26 to 30, wherein the first communication device (10) is further configured to broadcast a public key to other communication devices (10a; 10b) within said neighborhood; wherein the first communication device (10) is further configured to encrypt signals to other communication devices (10a; 10b) within said neighborhood with a private key; and

wherein the first communication device (10) is further configured to decrypt signals from each respective other communication device (10a; 10b) within said neighborhood with a respective public key of each of said respective other communication devices (10a; 10b).

32. The first communication device (10) according to any of the claims 26 to 31 , wherein the first communication device (10) comprises communication circuitry (13) configured to broadcast the presence of said first communication device (10) to other communication devices (10a; 10b) within said neighborhood, to detect other communication devices (10a; 10b) within said neighborhood, to send a report at least to other communication devices (10a; 10b) within said neighborhood when a communication device is missing from said neighborhood, and to send a report at least to other communication devices (10a; 10b) within said neighborhood when a communication device that has been reported as missing is detected in said neighborhood.

33. The first communication device (10) according to claim 32, wherein the communication circuitry (13) is further configured to broadcast a public key to other communication devices (10a; 10b) within said neighborhood.

5 34. The first communication device (10) according to any of the claims 26 to 33, wherein the first communication device (10 comprises a processor (1 1 ) and a memory (12), said memory (12) comprising instructions executable by the processor (1 1 ), whereby the processor (1 1 ) is operative to determine if a communication device is missing from said neighborhood, based on detected communication devices (10a;

10 10b) within said neighborhood.

35. The first communication device (10) according to claim 34, whereby the processor (1 1 ) is further operative to encrypt signals to other communication devices (10a; 10b) within said neighborhood with a private key; and

15 whereby the processor (1 1 ) is further operative to decrypt signals from each respective other communication device (10a; 10b) within said neighborhood with a respective public key of each of said respective other communication devices (10a; 10b).

20 36. A computer program comprising instructions, which when executed by at least one processor, cause the processor or processors to:

prepare information representing the presence of a first communication device (10), for broadcasting to other communication devices (10a; 10b) within a neighborhood of said first communication device (10), wherein said neighborhood 25 comprises communication devices within communication range of said first communication device (10);

read information regarding other communication devices (10a; 10b) detected within said neighborhood;

determine if a communication device is missing from said neighborhood, 30 based on detected communication devices (10a; 10b) within said neighborhood;

prepare a report that a communication device is missing from said neighborhood, for sending at least to other communication devices (10a; 10b) within said neighborhood; and prepare a report that a communication device that has been reported as missing is detected in said neighborhood, for sending at least to other communication devices (10a; 10b) within said neighborhood.

5 37. A carrier comprising the computer program of claim 36, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

10 38. A first communication device (10) for supporting monitoring of items in physical vicinity of one another, wherein the first communication device (10) comprises:

a preparation module (100) for preparing information representing the presence of said first communication device (10), for broadcasting to other communication devices (10a; 10b) within a neighborhood of said first communication 15 device (10), wherein said neighborhood comprises communication devices within communication range of said first communication device (10);

a reading module (200) for reading information regarding other communication devices (10a; 10b) detected within said neighborhood;

a determining module (300) for determining if a communication device is 20 missing from said neighborhood, based on detected communication devices (10a;

10b) within said neighborhood;

a report module (400) for preparing a report that a communication device is missing from said neighborhood, for sending at least to other communication devices (10a; 10b) within said neighborhood; and for preparing a report that a 25 communication device that has been reported as missing is detected in said neighborhood, for sending at least to other communication devices (10a; 10b) within said neighborhood.

39. A master node (20) configured to support monitoring of items in physical vicinity 30 of one another,

wherein the master node (20) is configured to broadcast the presence of said master node (20) to communication devices (10; 10a; 10b) within a neighborhood- based network (3), said neighborhood-based network (3) comprising a plurality of items (2; 2a; 2b) to be monitored, each item of said plurality of items being provided with a respective communication device (10; 10a; 10b), said neighborhood-based network (3) being based on a respective neighborhood of each of said respective communication devices (10; 10a; 10b), wherein each of said respective

5 neighborhoods comprises communication devices (10a; 10b) within communication range of each of said respective communication devices (10), said neighborhood- based network (3) being formed based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication

10 devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood;

wherein the master node (20) is configured to receive information representing the presence of items (2; 2a; 2b) within said neighborhood-based network (3); and

15 wherein the master node (20) is configured to determine if an item is missing from said neighborhood-based network (3), based on said received information, wherein said received information is based on each of said respective communication devices (10) reporting at least to other communication devices (10a; 10b) within its respective neighborhood

20 when a communication device is missing from its respective neighborhood, and

25 40. The master node (20) according to claim 39, wherein the master node (20) is part of said neighborhood-based network (3).

41 . The master node (20) according to claim 39 or 40, wherein the master node (20) is further configured to initiate forming of said neighborhood-based network (3).

30

42. The master node (20) according to any of the claims 39 to 41 , wherein the master node (20) is further configured to broadcast a public key to said communication devices (10; 10a; 10b) within said neighborhood-based network (3); wherein the master node (20) is further configured to encrypt signals to communication devices (10; 10a; 10b) within said neighborhood-based network (3) with a private key; and

wherein the master node (20) is further configured to decrypt signals from 5 each respective communication device (10; 10a; 10b) within said neighborhood- based network with a respective public key of each of said respective communication devices (10; 10a; 10b).

43. The master node (20) according to any of the claims 39 to 42, wherein the 10 master node (20) comprises communication circuitry (23) configured to broadcast the presence of said master node (20) to communication devices (10; 10a; 10b) within said neighborhood-based network (3), and to receive said information representing the presence of items (2; 2a; 2b) within said neighborhood-based network (3).

15

44. The master node (20) according to claim 43, wherein the communication circuitry (23) is further configured to broadcast a public key to said communication devices (10; 10a; 10b) within said neighborhood-based network (3).

20 45. The master node (20) according to any of the claims 39 to 44, wherein the master node (20) comprises a processor (21 ) and a memory (22), said memory (22) comprising instructions executable by the processor (21 ), whereby the processor (21 ) is operative to determine if an item is missing from said neighborhood-based network (3), based on said received information.

25

46. The master node (20) according to claim 45, whereby the processor (21 ) is further operative to initiate forming of said neighborhood-based network (3).

47. The master node (20) according to claim 45 or 46, whereby the processor (21 ) is 30 further operative to encrypt signals to communication devices (10; 10a; 10b) within said neighborhood-based network (3) with a private key, and

whereby the processor (21 ) is further operative to decrypt signals from each respective communication device (10; 10a; 10b) within said neighborhood-based network (3) with a respective public key of each of said respective communication devices (10; 10a; 10b).

48. A computer program comprising instructions, which when executed by at least one processor, cause the processor or processors to:

prepare information representing the presence of a master node (20), for broadcasting to communication devices (10; 10a; 10b) within a neighborhood-based network (3), said neighborhood-based network (3) comprising a plurality of items (2; 2a; 2b) to be monitored, each item of said plurality of items being provided with a respective communication device (10; 10a; 10b), said neighborhood-based network (3) being based on a respective neighborhood of each of said respective communication devices (10; 10a; 10b), wherein each of said respective neighborhoods comprises communication devices (10a; 10b) within communication range of each of said respective communication devices (10), said neighborhood- based network (3) being formed based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood;

read information representing the presence of items (2; 2a; 2b) within said neighborhood-based network (3); and

determine if an item is missing from said neighborhood-based network (3), based on said received information, wherein said received information is based on each of said respective communication devices (10) reporting at least to other communication devices (10a; 10b) within its respective neighborhood

when a communication device is missing from its respective neighborhood, and

49. A carrier comprising the computer program of claim 48, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

50. A master node (20) for supporting monitoring of items in physical vicinity of one another, wherein the master node (20) comprises:

a preparation module (120) for preparing information representing the presence of said master node (20), for broadcasting to communication devices (10; 10a; 10b) within a neighborhood-based network (3), said neighborhood-based network (3) comprising a plurality of items (2; 2a; 2b) to be monitored, each item of said plurality of items being provided with a respective communication device (10; 10a; 10b), said neighborhood-based network (3) being based on a respective neighborhood of each of said respective communication devices (10; 10a; 10b), wherein each of said respective neighborhoods comprises communication devices (10a; 10b) within communication range of each of said respective communication devices (10), said neighborhood-based network (3) being formed based on each of said respective communication devices (10) broadcasting its own presence to other communication devices (10a; 10b) within its respective neighborhood, and each of said respective communication devices (10) detecting other communication devices (10a; 10b) within its respective neighborhood;

a reading module (220) for reading information representing the presence of items (2; 2a; 2b) within said neighborhood-based network (3); and

a determining module (320) for determining if an item is missing from said neighborhood-based network (3), based on said received information, wherein said received information is based on each of said respective communication devices (10) reporting at least to other communication devices (10a; 10b) within its respective neighborhood

when a communication device is missing from its respective neighborhood, and