The present invention is related to wireless devices roaming between wireless access points in a network or from a wireless access points in one network to a wireless access point in another network.

BACKGROUND OF THE INVENTION

In general wireless networks are constrained by many parameters and design issues, like differences in electronic interface standards, communication protocols, radio frequencies, public regulations and legislations and vendor-specific implementations. Some classes of devices and their protocols are usually designed for use in specific fields of applications, for example within a private home environment, in metering applications, welfare technology, within hospitals or as part of a wireless "Internet of everything".

When using different devices one can end up with a need of implementing different proprietary network standards.

Radio communication protocols can be divided in some major classes: open standards like the ones defined in the European Norms (EN standards, e.g. KNX RF and Wireless M-Bus), and industry standards driven by consortiums or special interest groups (e.g. ZigBee, Bluetooth, Z-Wave and Thread). There are also other vendor-defined protocols, which may or may not have been released into the public domain (e.g. NEXA by ARC Technology). The regulating authorities behind these different protocols will normally not take any actions facilitating interoperability or cooperation between devices with different radio communication protocols, but focus on the development and deployment in the market of their own specific standards. Further, suppliers of radio-operated devices may find it commercially beneficial to introduce a new protocol instead of utilizing existing standards.

Some of the problems discussed above is addressed in US 10693719 B2 by the same inventor of the present application.

Patients in hospital are usually monitored with respect to different parameters like blood pressure, oxygen levels etc. in their blood. Monitoring possible dehyd ration and more critical parameters like breathing can also be monitored by respective adapted devices. Some devices and instruments are fixed to a location wherein a hospital bed is positioned. Data acquisition is then normally done via cables from a device or sensor attached to a patient and to a configured terminal. A terminal can in turn be communicating over for example Internet. However, there is some concern regarding operational safety and juridical problems of letting medical data of specific patients be transmitted over Internet due to well-known hacker activity, for example.

Therefore, there has been a development towards other types of networks separate from standard Internet supporting wireless devices replacing many of the stationary instruments known from hospitals.

It is therefore, for example in hospitals, often mandatory to use separate networks, for example one standard Internet and at least one more specialized network isolated from the Internet. The above-mentioned publication US 10693719 B2 disclose a mesh network that for example can control wireless device inside a hospital room, or rooms, and which is also able to control wireless devices in a house and garden that controls for example burglar alarms, water leakage detectors, regulate temperature of the house etc. In a garden, the system may for example turn on watering of a lawn at scheduled times or as a result of a sensor input indicating draught.

Respective wireless access points are normally equipped with at least two wireless communication ports, wherein one port is communicating over a selected network standard, which may be a mesh network for example, connected to a control unit and the other port is communicating with at least one wireless device connected wirelessly to the access point.

The typical aspect of these applications is that the network usually covers a limited geographical area. Wireless access points of a network are distributed for example within a hospital room or rooms, or inside a house and/or garden, and typical wireless devices in communication with these wireless access points are often battery operated. Reducing battery power consumption is done for example by operating devices over shorter radio ranges. An example of a low power system is the Blue Tooth Low Energy (BLE) standard for Blue tooth devices. In larger hospitals several smaller networks can be installed. When a wireless device connected to a wireless access point moves away from the access point, for example when a patient is moved by a porter in a hospital, the wireless connection will be lost when the distance is larger than the radio range of the wireless device. There exists roaming solutions that allows a roaming device to connect to another wireless access point within radio range of the device. Refer for example US 10693719 B2. However, roaming between different smaller networks installed for example in a hospital building may require that a device roams between different wireless networks, for example when a patient is moved from a room to a CT scanner located elsewhere in the building or even in another building. Such networks may also be of different standards.

When a device connects to a wireless access point there is at least two different radio standards available, Connection Oriented Protocols (COP devices) and Connection Less Protocols (CLP devices). The problem is therefore to identify at least the connection parameters of the device trying to connect to a next specific wireless access point being close enough to the device. With reference to US 10693719 B2 a device moving away from an access point triggers a sequence of operations. The missing connection of the device is detected by a bridge, which is a wireless connection point, the bridge sends connection related data to a central control unit end when another bridge (wireless access point) connects to the device the control unit sends the connection data to that bridge, which initialize the device and the connection.

However, if the device is used in real time applications, for example monitoring critical parameters of a patient, this may require not only the establishment of the new connection, but as well establishing a correct dataflow connection to a specific real time application program running in a configured and connected data system as quickly as possible. Minimizing the time delay such that a dataflow stream is not interrupted can be of great importance in some instances not only in hospital environments but also in for example metering applications in industry. The time from a connection of a roaming device is made to a dataflow streaming correctly to an application can be of great importance.

There can also be more than one wireless access point that comes within radio range of the device when the device is roaming. Therefore, it can also be a problem related to qualifying which connection should be allowed for the roaming deice to the wireless network. Therefore, there is a need of an improved roaming system for wireless networks.

OBJECT OF THE INVENTION

It is a further object of the present invention to provide an alternative to the prior art.

In particular, it may be seen as an object of the present invention to provide a system controlling roaming of wireless devices as well as roaming of devices from one network to another network.

SUMMARY OF THE INVENTION

Thus, the above-described object and several other objects are intended to be obtained in a first aspect of the invention by providing a system controlling roaming of devices from one access point to one of several access point the roaming device may connect with, wherein a control unit of the network sends a message to access points located around the access point the device disconnected from, wherein the message comprises at least connection related data.

The invention is particularly, but not exclusively, advantageous for obtaining a network system supporting roaming of wireless devices, wherein a first control unit is configured with at least network topology data identifying relative positions between wireless access points of a first network distributed within a first geographical area, when a connected wireless device roams out of radio range from a wireless access point connecting the device to the network, the wireless access point is configured to send a message to the first control unit comprising at least a device identity, device type and connection data related to the roaming device, the first control unit is configured to use the network topology data identifying all nearby located wireless access points surrounding the wireless access point the device disconnected from and submits at least the device identity and connection data to each of the respective access points surrounding the access point the device was connected to, when a next wireless access point of the respective access points surrounding the access point the device was connected to is within radio range of the roaming device the next wireless access point comes in contact with the roaming device and uses the already submitted connection data to establish the connection with the roaming device, and the next wireless access point sends a message to the first control unit informing of the new connection of the roaming device.

Respective aspects of the present invention may each be combined with any of the other aspects. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described herein.

DESCRIPTION OF THE FIGURES

The roaming system according to the present invention will now be described in more detail with reference to the accompanying figures. The attached figures illustrates an example of embodiment of the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figure 1 illustrates an example of embodiment of the present invention.

Figure 2 illustrates another example of embodiment of the present invention.

Figure 3 illustrates another example of embodiment of the present invention.

Figure 4 illustrates an example of network topology data DETAILED DESCRIPTION OF AN EXAMPLE OF EMBODIMENT

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Further, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

An aspect of the present invention is to implement a roaming system in a wireless network based on a "look ahead" principle, which implies that when a device disconnects from a wireless access point a control unit prepares surrounding wireless access point around the disconnected access point of the possibility that the roaming device might connect to one of the respective surrounding wireless access points.

Connection related data can be dependent on respective radio protocols used by respective devices. Radio protocols can be divided into two major classes based on connectivity, which are connection-less protocols (CLP) and connection-orientated protocols (COP) and some protocols support both connectivity classes based on modes or context. These devices represent different types of devices.

Connection-less protocols does not have any method or procedure to establish a logical link between devices and transmitted data may be considered broadcast (to all devices within range) or multicast (to a designated group of devices within range), and as soon as a CLP device have data to send, it will normally just be transmitted.

Connection-orientated protocols require a logical connection to be established between the devices before transferring data. This is generally accomplished by following a set of rules that specifies how a connection should be initiated, negotiated, managed and eventually terminated. In most prior art protocols, COP devices will establish a connection between each other in a peer-to-peer topology. The devices may store connectivity data for later sessions, but if one of the devices is moved to another location being outside radio range of the previously connected peer, it will not be able to connect, but have to establish a new connection to a different peer device, and all previous session specific data may be invalid.

An example of a protocol supporting both CLP and COP data exchanges is BLE as known to a person skilled in the art. When a BLE peripheral device is not in a connection, it is denoted as a BLE advertiser or broadcaster, and when a BLE central device it not in a connection, it is denoted as a BLE scanner or observer. Connection less data exchange in BLE is unidirectional, from the advertiser/broadcaster to the scanner/observer. When in a connection BLE supports duplex communication. Networks like mesh networks are controlled and operated vi a control unit (CU) that controls and sets up communication between devices and computer systems. In this context it is important to understand that the CU is not necessarily the computer system running for example real-time applications discussed above. The CU can in one end communicate over a separate network connected to a computer system running a specific real time application program. In a sense a CU may sometimes be regarded as an intelligent gateway.

Figure 1 illustrates an example of a network installed in a hospital building 10. A hospital bed 12 and a patient 12 is illustrated. On a wall of the upper room there are indicated three wireless access points 11a, 11s, 11c. The lower room has a CT scanner 13 and three wireless access points lid, lie, Ilf mounted on a wall of the lower room.

This configuration of wireless access point is not illustrating an actual deployment of access points but is merely illustrating principles of the present invention.

The patient 14 is illustrated walking in the upper room. The patient may for example have a blood pressure sensing device around for example an arm. This device is in connection with one of the respective wireless access points. The data sent from the blood pressure sensor can be monitored by a remote computer system. The application running in computer system can be seen as a real-time data application, and the data producing device (the blood pressure sensor in this example) should provide data in an uninterrupted manner without longer delays between data samples. The situation is that if the sensor detects that there is no blood pressure this is in fact a possible indication of a fatal event for the patient. Another possibility is that absence of data is due to low battery capacity in the blood pressure sensor.

Both of these situations should trigger a warning to a central alarm center. To avoid false alarms the roaming of the patient 14 between access point 11a and for example access point lib should not introduce delays in the reconnection of the roaming blood pressure device (i.e., patient).

Another roaming situation is that the patient 14 is moving out of the upper room and down to the lower room for a CT scan investigation. Then the roaming moves between several wireless access points and connections and reconnections should not delay for example blood pressure readings. However, sometimes a real time data acquisition can be delayed between two different access points. For example, a patient can be moved in a hospital bed to for example the CT scanner 13 by a porter. Then it is within the scope of the present invention to configure and instruct for example the wireless blood pressure sensor not to allow connections to other wireless access points than for example the wireless access point Ilf in the lower room in Figure 1. This is possible to do since the porter supervises the patient when the porter moves the patient. In this situation there is a planned operation wherein a time slot has been allocated for the patient at the CT scanner. Therefore, the system is aware of the timing of the movement. A device identity for a device being used by a patient in a sense an identity also of the patient. Therefore, a planning system of a hospital can then schedule the time for a CT scan for a patient for example with the device identity the patient is wearing. Therefore, it is expected that a patient staying in bed 12 disconnects from for example the wireless access point 11a within an expected time. In such a situation the system can instruct the device only to connect with a wireless access point having a specific and unique address like for example the wireless access point Ilf located adjacent to the CT scanner.

According to an aspect of the present invention, access point Ilf is provided with respective connection data that enables a quick reconnection of the roaming device patient 14 is wearing. Further, since both the disconnection and reconnection is about to happen within a time span dictated by the distance between the wireless access point 11a and the wireless access point Ilf, any delays of the patient ^' s arrival can be identified quickly by personal at the CT scanner and actions can be initiated to make sure that the patient is found and guided towards the correct destination. In this manner idle time at the CT scanner can be minimized.

It is also possible to use wireless access points to monitor movements of roaming devices by just start a connection thereby identifying a device identity and then terminate the connection before the connection is fully operational.

Figure 2 illustrates a floor plan with several room, a corridor and an elevator 17. Inside one room there is located a computer system 18 that also can serve as a control unit for respective wireless access points llg to lln rooms and the corridor. Inside the elevator 17 there is also a wireless access point 16. If the control unit 18 is controlling the wireless access point 16 there might be necessary with a radio repeater installed in the elevator shaft which is not illustrated.

Figure 3 illustrates a typical villa 19 wherein a dog 21 is moving around. A wireless access point 20a is located outside in the garden. Wireless communication from such a location to a control unit inside the house can be achieved with a long-range radio in the wireless access point 20a. Wireless access points 20b and 20c is located on outside surfaces of the house 19. The dog can have a mounted wireless tracker device on the dog collars and if the dog moves around in the garden respective wireless access point connects with the tracker device making it sure that the dig stays in the garden. If for example the dog passes the wireless access point 20c close to the gate into the premises the disconnection of the tracker device is close to the garden itself and there is a possibility that the dog moves away from the house 19 and into a neighbor's garden. If the neighbor has a network with wireless access point the control unit for the house 19 can send a message to a control unit in the house of the neighbor that the dog maybe will connect to a wireless access point controlled by this control unit.

With reference to Figure 1 it is possible to have a first network covering the geographical area defined by the upper floor of the building 10 and a second network covering the geographical area defined by the lower floor of the building.

It is within the scope of the present invention to provide roaming between different networks. There can be more than one second network located around a geographical are of a specific network.

An example of network topology data is illustrated in Figure 4. Relative distance and relationship between respective access point A1 to A13 of network A is illustrated. It is also illustrated a network B that is located outside network A on an outside of the access points Al- A4. The access points A1-A4 is located in an edge zone of the geographical area the first network with the access points A1-A13 covers.

A further network C is illustrated located on an outside of an edge zone of the geographical area network A covers outside the access point A4, A5, A9.

The network topology data as illustrated in Figure 4 fits easily in a matrix of 15 cells. However, it can also be implemented as a list of access point wherein where for example access point A1 is listed as being surrounded by Network B and access point A2 and possibly A6 and A7. Such relationship can in some instances also include to list A8 as a nearby access point for Al. This ca be the case if there actually is a short distance between A and A8, for example when A8 actually is located in a room next to the access point Al. The list can be made for all access points wherein the first data entry in a list line is the name or address of an access point. The next data items on the list line is the name or addresses of the surrounding access points.

A system according to the present invention supports roaming of wireless devices, wherein a first control unit is configured with at least network topology data identifying relative positions between wireless access points distributed within a first geographical area of a first network.

When a connected wireless device roams out of radio range from a first wireless access point the device is connected with, the first wireless access point is configured to detect the incident and sends a message to the first control unit comprising at least a device identity and connection data related to the roaming device.

It is further within the scope of the present invention that the message can include a device type indicator, for example an indicator representing a COP device or a CLP device etc.

The first control unit is configured to use the network topology data identifying all nearby located wireless access points surrounding the first wireless access point disconnected from the roaming device and submits at least the device identity and connection data to each of the respective access points surrounding the first access point as identified by the network topology data.

When a second wireless access point of the respective access points surrounding the first access point is within radio range of the roaming device the second wireless access point comes in contact with the roaming device and uses the already submitted connection data to establish the connection with the roaming device, and the second wireless access point sends a message to the first control unit informing of the new connection of the roaming device. The system according to the present invention allows roaming between respective networks and wherein at least one second control unit of at least one second wireless network controls respective wireless access points distributed within at least a second geographical area of the at least one second network. The at least one second control unit is configured with at least network topology data identifying relative positions between wireless access points within the at least one second geographical area.

When a roaming device from the first network is roaming out of radio contact with a wireless access point located in an edge zone of the first geographical area, the at least one second control unit is signalled with a message from the first control unit about the possible arrival into the second geographical area by the roaming device.

The message comprises at least a device identity and specific connection data of the possible arriving roaming device from the first geographical area into the at least second geographical area.

The second controller unit is configured to submit the device identity and connection data to wireless access points located in an edge zone of the second geographical area facing the first geographical area.

When a connection is established between the roaming device and one of the wireless access points in the edge zone of the second geographical area, the second controller unit signal the first controller unit of the new established connection.

The respective network topology data can also comprise information about neighbouring networks round the respective first and second geographical area.

When the first controller unit send the device identity and connection data to the second controller the second controller can rename the device identity by concatenating the device identity with a unique name of the first network.

Respective devices can be connection-oriented devices or connectionless devices. The first and at least the second control unit is configured with protocol parameters related to each respective device communication protocol. It is also within the scope of the present invention that a wireless access point is a network bridge configured with a first wireless communication port in communication with the first or second control unit and a second wireless communication port being a wireless access point for wireless devices. The second communication port can for example be a Bluetooth low energy radio ports.

Respective networks of the roaming system according to the present invention can for example be a mesh network.

There are further optional configurations possible that are within the scope of the present invention. For example, at least one wireless access point can be configured with a long-range radio. Encryption and decryption of payloads transmitted in the first and at least second network is also possible to achieve, for example in configured wireless access points configured with respective encryption and decryption keys.

Connections between a wireless access point can be established in a pairing process. Encryption and decryption related data can be part of a pairing process.

An example of embodiment of the present invention may comprise that the network topology data are configured with a time indicator indicating a typical time a device uses when roaming from a specific located access point to each of the surrounding the respective access points surrounding the specific located access point and when the first or at least the one second control unit does not receive a message of a new connection for a roaming device, an alarm can be configured to be sent to an external alarm central.

It is also within the scope of the present invention that a roaming device can be configured to decline a connection to a wireless access point forming a new connection based on an access point identity of the wireless access point. In such circumstances the alarm will not be issued.