Title: Mobile monitoring system and method
The invention relates to a mobile monitoring system and a method for mobile monitoring.
Mobile monitoring systems are known per se. The known mobile monitoring systems are e.g. used for monitoring vital functions or physical parameters of a patient.
One known monitoring system comprises a sensor device worn by a patient, which sensor device is arranged to determine values of parameters of the patient, for instance a value of the parameter blood pressure. The sensor device is further arranged to transmit the determined value to a user unit, e.g. operated by a physician, for inspection and monitoring.
The known monitoring systems have the disadvantage that they are commonly designed for a predetermined purpose and therefore lack versatility, further, the known systems may be complicated to install onto the patient, and/or difficult to operate. It is an object of the invention to provide a more versatile and/or user friendly mobile monitoring system.
Thereto, according to the invention, a mobile monitoring system is provided, comprising at least one mobile sensor system arranged for detecting a parameter value and wirelessly transmitting a sensor signal associated with said parameter value, a mobile base unit arranged for receiving the sensor signal from the at least one mobile sensor system and for wirelessly transmitting a mobile base unit signal associated with the received sensor signal, wherein the at least one mobile sensor system and the mobile base unit are arranged to be carried by a movable object or movable organism, wherein the mobile monitoring system further comprises a back-end system arranged for receiving the mobile base unit signal, thus allowing a wireless communications link between the mobile base unit and the back-end system, and making data associated with the mobile base unit signal available to a user.
It will be appreciated that herein a signal, such as the sensor signal, may have data associated therewith, e.g. data associated with the parameter value, preferably in digital form.
Hence, the mobile base unit can be wirelessly connected to, one or a plurality of mobile sensor systems. This provides the advantage that the mobile sensor system(s) can be easily applied to the movable object or movable organism, e.g. patient, while the mobile base unit can separately be applied to the patient, e.g. worn on the clothing or carried in a pocket of a person's clothing, without the need of any physical connection between the mobile sensor system(s) and the mobile base unit. Further, a user, such as a physician, may monitor the data associated with the mobile base unit signal, which may comprise data relating to the detected parameter value, via the wireless communications link and via the back-end system.
Preferably, the back-end system is further arranged for transmitting a back-end system signal and the mobile base unit is further arranged for receiving the user unit signal from the user unit. Hence, it is possible to communicate data from the mobile base unit towards the back-end system and vice versa. It is for instance possible for the physician using the back-end system, e.g. via a user terminal and an interface, such as a web-application, to transmit commands, such as feedback, e.g. tactile, audio, and/or visual feedback signals, to the patient carrying the mobile base unit.
Preferably, the mobile base unit is provided with an actuator, e.g. a loudspeaker or a vibratory element, and is arranged for actuating the actuator on the basis of the received back-end system signal.
Preferably, the mobile base unit is further arranged for wirelessly transmitting a mobile-base-unit-to-sensor-system signal, e.g. associated with the received back-end system signal, and the at least one mobile sensor system is arranged for receiving the mobile -base-unit-to-sensor-system signal. Preferably, the at least one mobile sensor systems is provided with an actuator. Hence, it is possible to activate the actuator by receiving a command from the mobile base unit or from the back-end system via the mobile base unit. Thus, it is for instance possible for the physician using the back-end system, e.g. via a user terminal and an interface, such as a web-application, to transmit commands, such as feedback, e.g. tactile, audio, and/or visual feedback signals, to the sensor system, via the mobile base unit. Also, it is possible for the patient using the mobile base unit, to transmit commands, e.g. to actuate the actuator, to the sensor system. In a preferred embodiment, the mobile base unit is arranged such that it can be wirelessly connected to different mobile sensor systems, e.g. determining values of different parameters, transmitting sensor signal using different wireless communications protocols, transmitting sensor signals in different (data) formats and/or manufactured by different manufacturers. Thus, a very versatile system is provided.
Preferably, the mobile base unit is arranged for filtering and/or processing data associated with the received sensor signal. Thus, e.g. noise may be removed from the data associated with the received sensor signal, or signal processing operations, such as averaging, (Fourier) transformation, etc. may be performed.
Preferably, the mobile base unit is arranged for compressing and/or prioritizing data associated with the received sensor signal. Thus, it is possible to reduce the amount of data transmitted via the wireless communications link to the back-end system. According to a first additional aspect of the invention, at least one of the at least one mobile sensor systems is arranged for detecting a first parameter value and a second parameter value and for transmitting a composite sensor signal associated with the first and the second parameter values, wherein the mobile base unit is arranged for decomposing the received composite sensor signal into a first sensor signal representative of the first parameter value and a second sensor signal representative of the second parameter value or for decomposing composite sensor data associated with the received composite sensor signal into first sensor data representative of the first parameter value and second sensor data representative of the second parameter value. This provides the advantage that if the mobile base unit is associated with a mobile sensor system transmitting a composite sensor signal, this composite sensor signal (or the composite sensor data) is decomposed in the mobile base unit. Thus, the mobile base unit comprises separate data associated with the separately determined parameters, which were combined in the composite sensor signal. Thus, it is possible to separately process the separate data associated with the separately determined parameters.
According to a second additional aspect of the invention, the mobile base unit is arranged for converting first sensor data associated with a first sensor signal that is transmitted in a first data format and second sensor data associated with a second sensor signal that is transmitted in a second data format, differing from the first data format, into a first and second converted sensor data, respectively, of identical data format. Hence, it is possible to perform identical or similar operations to the first and second converted sensor data, irrespective of the nature of the associated first and second sensor signals.
Preferably, the mobile base unit comprises a first plug-in software module for converting the first sensor data into the first converted sensor data and/or a second plug-in software module for converting the second sensor data into the second converted sensor data. Thus, it is possible to allow any type of sensor signal to be converted into a properly formatted converted sensor signal, preferably uniform for all converted sensor signals, by providing the correct plug-in software module.
According to a third additional aspect of the invention, the mobile base unit is arranged for gathering data associated with received sensor signals into a data record, and for processing the data record. Here processing may e.g. comprise transmitting of the data record. Thus, a well-defined data structure may be provided.
Preferably, the mobile base unit is arranged for gathering the sensor data associated with received sensor signals into a data record such that sensor data associated with each particular sensor device of the at least one mobile sensor system is comprised in a respective data-channel of the data record. Thus, the data record comprises a single data-channel for each sensor device. Hence, retrieving data from the data record is made particularly easy. Optionally, the data record comprises for each data-channel a relative priority of that data-channel.
According to a fourth additional aspect of the invention, the mobile base unit is arranged for, during consecutive predetermined time intervals, for each predetermined time interval adding to a single data record all first sensor data associated with the first sensor signal received during that predetermined time interval and all second sensor data associated with the second sensor signal received during that predetermined time interval, and subsequently processing the data record. Here processing may e.g. comprise transmitting said data record. This provides the advantage that the first and second sensor signal are synchronised upon reception by the mobile base unit. Thus, the first and second sensor signal need not be synchronised at a later time, e.g. upon transmitting the mobile base unit signal, which proves to be difficult when receiving the first and second sensor signal via a wireless communications connection. Since, however, the first and second sensor signals received during one predetermined time interval are grouped into the same data record, the data associated with the first and second sensor signal and comprised in that data record is synchronised in time.
According to a fifth additional aspect of the invention, the mobile base unit is arranged for, during consecutive predetermined storage intervals, for each predetermined storage interval accumulating the sensor signal or all data associated with that sensor signal received during that predetermined storage interval, and transmitting the mobile base unit signal associated with the accumulated sensor signal or data associated with the received sensor signal after lapse of that storage interval. Herein, a plurality of data records may be accumulated during that predetermined storage interval. This provides the advantage that data may be transmitted from the mobile base unit to the back-end system in batches, which may e.g. reduce power consumption of the mobile base unit.
In a generally applicable embodiment, the mobile base unit comprises an indicator for indicating data associated with the received sensor signal and/or data associated with the received back-end system signal to the user and/or movable organism. Preferably, the indicator comprises a display, and the data associated with the received sensor signal and/or associated with the received back-end system signal is indicated to the user and/or movable organism via a user interface. According to a sixth additional aspect of the invention, the mobile base unit is arranged for making the data associated with the received sensor signal, and/or the back-end system signal, available to the user interface or third party software components, e.g. a human machine interface, using an Application Programming Interface (API). This provides the advantage, that the user interface may be modified, or be tailor made, to the needs of a specific patient or user, without the need to modify software, running on the mobile base unit, relating to receiving and processing the sensor signals and/or back- end system signal and transmission of the base unit signal. Preferably, the data associated with the received sensor signal and/or the data associated with the received back-end system signal is communicated to the user interface using the Internet Protocol (IP).
In an embodiment, the mobile base unit comprises a, preferably nonvolatile, memory for storing the data associated with the received sensor signal. Thus, in addition to transmitting data associated with the received sensor signals to the back-end system, such data may also be stored into the memory. Preferably, all data associated with all received sensor signals is stored into the memory. This provides the possibility of retrieving any data, e.g. in case of loss of data due to malfunction or transmission errors in the wireless communication to the back-end system. According to a seventh additional aspect of the invention, the mobile base unit is arranged to transmit historical data stored in the memory of the mobile base unit, e.g. data not previously transmitted, upon request by the back-end system or when triggered by a special event. Thus, it is possible to selectively omit transmission of data associated with, certain or certain parts of, received sensor signals and transmit previously non-transmitted data when needed. This may e.g. be useful in case of a medical episode, in which a user of the back-end system is interested in data predating the onset of the medical episode by a certain amount of time.
In an embodiment, the mobile base unit is arranged for transmitting status information of the mobile base unit. Such status information may comprise proper operation or malfunction information, free memory amount, remaining battery power, periodic acknowledgement of proper operation of the mobile base unit (mobile base unit "heartbeat"), etc.
According to an eighth additional aspect of the invention, the data record comprises a system status channel comprising data indicating the status information of the mobile base unit and/or mobile sensor system(s). This provides the advantage that the data record comprises both data associated with received sensor signals and status information of the mobile base unit and/or mobile sensor system(s) in a (time-) synchronised way. Preferably, the system status channel is awarded a higher priority than the data channels comprising data associated with sensor signals.
According to a ninth additional aspect of the invention, the mobile base unit is arranged for transmitting data for remote management of the mobile base unit towards the back-end system. Preferably, the back-end system is arranged for transmitting data for remote management of the mobile base unit towards the mobile base unit. The back-end system may transmit a system management signal comprising data relating to instructions and/or parameters concerning operation of the mobile base unit towards the mobile base unit. The mobile base unit may transmit a system management response, e.g. comprising acknowledgement of receipt of the system management signal and/or a new mobile base unit configuration, towards the back-end system. Preferably, the system management signal and the system management response is transmitted over a system management channel, which forms a second wireless communications link between the mobile base unit and the back-end system, separate of the wireless communications link (hence also referred to as data records channel) used for transmitting the mobile base unit signal and the back-end system signal.
Preferably, the system management channel is awarded top priority over the data records channel comprising data associated with sensor signals and the system status channel. Hence, operation of the system is safeguarded, even in situations where the system has to communicate high volumes of data associated with received sensor signals from the mobile base unit to the user unit.
According to a tenth additional aspect of the invention, the mobile base unit is arranged to modify the content of the data record to be transmitted based on a measured characteristic of the wireless communications link, such as a measured bandwidth, delay and/or delay variation of the wireless communications link. This provides the advantage that the mobile base unit may utilise the available bandwidth of the wireless communications link as desired, e.g. to the most optimal level from a communications link perspective, or the mobile base unit may decide to switch to an alternative wireless communications link based on a policy based mechanism. Such policy based mechanism allows the mobile base unit to assess parameters (e.g. power consumption, communication costs and/or communications speed) of available wireless communications links and determine which of the available links to use based on a policy, such as minimum required transmission time (e.g. in view of power consumption), maximum allowable transmission costs or the like.
Preferably, the mobile base unit is arranged to modify the content of the data record to be transmitted on the basis of the relative priority of the channels of the data record. Thus, one or more channels of the data channels comprising data associated with received sensor signals and the system status channel which are deemed more important than other channels may be spared when modifying the content of the data record. Alternatively, or additionally, those data channels among the data channels which are deemed more important than other data channels may be spared when modifying the content of the data record.
In an embodiment, the mobile base unit is arranged for determining the characteristic, such as bandwidth, of the wireless communications link on the basis of a filling degree of a transmission buffer of the mobile base unit. It will be appreciated that when the filling degree of the transmission buffer increases, e.g. the bandwidth of the wireless communications link is decreasing, as evidently a decreased amount of data can be transmitted per unit of time. It is possible that the mobile base unit is arranged to remove a channel from the data record to be transmitted if the measured characteristic of the wireless communications link fulfils a predetermined criterion, e.g. if the bandwidth of the wireless communications link is lower than a predetermined threshold bandwidth, if a time delay in the wireless communications link is more than a predetermined threshold time delay, and/or if a variation in the time delay in the wireless communications link is more than a predetermined threshold variation.
Alternatively, or additionally, it is possible that the mobile base unit is arranged to increase an amount of filtering of data in a channel in the data record to be transmitted if the measured characteristic of the wireless communications link fulfils a predetermined criterion, e.g. with respect to bandwidth, delay or variation in delay.
Alternatively, or additionally, it is possible that the mobile base unit is arranged to increase an amount of data compression, or apply stronger filtering of data associated with a sensor signal, of data in a channel in the data record to be transmitted if the bandwidth of the wireless communications link is lower than a predetermined threshold bandwidth.
According to an eleventh additional aspect of the invention, the back-end system is arranged to provide a surrogate object representing the mobile base unit, e.g. utilizing the Jini Surrogate Architecture. This provides the advantage that the mobile base unit only interacts with the back-end system (i.e. the surrogate object) and the back-end system emulates and handles all mobile base unit interactions with a plurality of (mobile base unit data) users, while the mobile base unit need not communicate with each user or a the plurality of users separately.
In general it may be preferred that the at least one mobile sensor system is connected or connectable to the mobile base unit via a, preferably short-range, wireless communications connection, such as Bluetooth or ZigBee. It will be appreciated that if a plurality of mobile sensor system is communicatively connected to the mobile base unit, different wireless communication connections, e.g. of different types, may be used side by side.
In general, it may be preferred that the mobile base unit is connected or connectable to the back-end system via a wireless communications link, such as GSM, GPRS, UMTS, HSDPA, EDGE, WLAN and/or WiMax.
In an embodiment, at least one of the mobile sensor systems comprises an event button and is arranged for transmitting a sensor signal associated with a status of the event button.
It will be appreciated that it is possible that a data channel associated with the event button sensor signal may be awarded a higher priority than other data channels associated with other sensor signals. Upon receiving the mobile base unit data record, the back-end system interprets the data record and may search for event related data. If this data is available, the back-end system may create an event message (e.g. text, audio, visual) and may forward this message to a third party service provider: text to SMS or email service provider, audio/visual to MMS or phone service provider or internet application provider.
The invention also relates to a method for mobile monitoring, comprising: detecting at least one parameter value and wirelessly transmitting a sensor signal associated with said at least one parameter value using at least one mobile sensor system carried by a movable object or movable organism; receiving the sensor signal from the at least one mobile sensor system and wirelessly transmitting a mobile base unit signal associated with the received sensor signal using a mobile base unit carried by the movable object or movable organism; receiving the mobile base unit signal using a back-end system, thus establishing a wireless communications link between the mobile base unit and the back-end system; and making data associated with the mobile base unit signal available to a user.
The invention will now be further elucidated by means of a, non- limiting, example, referring to the drawing, in which
Fig. 1 shows a schematic representation of a first embodiment of a mobile monitoring system according to the invention;
Fig. 2 shows a part of the system of Fig. 1 in more detail; Fig. 3 shows an example of a data record according to the invention; and
Fig. 4 shows an example of user network functionality using a surrogate object representing a mobile base unit. Fig. 1 shows a schematic representation of a first embodiment of a mobile monitoring system 1 according to the invention. In this example, the monitoring system is arranged for monitoring physical parameters, for instance blood pressure, saturation level of blood, skin temperature, heart rate, etc, of a patient. The parameters can for instance be monitored by a user of the system, such as a physician.
In the example of Fig. 1, the system 1 comprises a Body Area Network (BAN) 2 which is communicatively connected or connectable to a user unit, in this example embodied as a user network (UN) 4. In this example, the BAN 2 is connected to the UN 4 via a wireless communications link, such as GSM (Global System for Mobile communications), GPRS (General Packet Radio Service), UMTS (Universal Mobile Telecommunications System),
HSDPA (High Speed Downlink Packet Access), EDGE (Enhances Data rates t for GSM Evolution), WLAN (Wireless Local Area Network), WiMax (Worldwide Interoperability for Microwave Access) etc.
In Fig. 1 the Body Area Network 2 comprises a plurality of mobile sensor systems 6.i (i=l,2,3,...). These mobile sensor systems 6.i are carried by the patient. Thereto, the mobile sensor systems 6.i may e.g. be connected to the body or clothing of the patient. Each mobile sensor system 6.i comprises at least one mobile sensor device 8.j (pl,2,3,...) for detecting a parameter of the patient. In this example, the first mobile sensor system 6.1 comprises two mobile sensor devices 8.1 and 8.2. In this example, the second mobile sensor system 6.2 comprises a single mobile sensor device 8.3. In this example, the third mobile senor system 6.3 comprises a single mobile sensor device 8.4. In this example, the first mobile sensor device 8.1 is a heart rate sensor for measuring the heart rate of the patient, and the second mobile sensor device 8.2 is a pulse oximeter (SpO2) sensor for measuring the amount of oxygen in the blood (saturation) of, the patient. In this example, the third mobile sensor device 8.3 is a temperature sensor for measuring skin temperature of the patient. In this example, the fourth mobile sensor device 8.4 is an event button that can be activated by the patient, e.g. when the patient starts to feel unwell. In Fig. 1, each mobile sensor system 6.i comprises a transmitter 10. i for transmitting a sensor signal associated with the detected parameter. Hence, the first transmitter 10.1 may transmit a first sensor signal associated with the measured heart rate and amount of oxygen in the blood. It will be appreciated that the first sensor signal may be a composite signal wherein two parameters detected by the first mobile sensor system 6.1, here the heart rate and the amount of oxygen in the blood, are combined, e.g. interleaved, encoded and/or encrypted. The second transmitter 10.2 may transmit a second sensor signal associated with the measured skin temperature. The third transmitter 10.3 may transmit a third sensor signal associated with a status (activated or non- activated) of the event button. The third transmitter may e.g. be arranged to only transmit the third sensor signal when the event button is activated, and refrain from transmitting the third sensor signal when the event button is not activated.
In the example of Fig. 1 the first, second and third sensor signals comprise sensor data associated with the respective detected parameters. In this example, the sensor signals comprise the sensor data in the form of digital data.
In Fig. 1, the Body Area Network 2 further comprises a mobile base unit 12. The mobile base unit 12 is carried by the patient. Thereto, the mobile base unit 12 may e.g. connected to the body or clothing of the patient. In this example, a general-purpose computer, such as a Personal Digital Assistant (PDA) is used as a (hardware) platform for the mobile base unit 12. The mobile base unit 12 comprises a receiver 14 for receiving the respective sensor signals from the sensor systems 6.i. In this example, the transmitters 10. i and the receiver 14 are arranged for, e.g. short range, wireless communication of the sensor signals, for instance via Bluetooth or ZigBee. Thus, the BAN 2 forms a wireless network comprising mobile sensor systems 6.i and a mobile base unit 12 carried by the patient.
In Fig. 1, the mobile base unit 12 further comprises a transmitter 18 for transmitting a mobile base unit signal. The mobile base unit signal may be associated with the sensor signals received by the receiver 14 as described herein below. In this example, the mobile base unit signal comprises mobile base unit data associated with the sensor data. In the example of Fig. 1, the mobile base unit 12 further comprises data processing means 16 for processing the received sensor signals (e.g. for processing the sensor data), if so desired, and generating the mobile base unit signal on the basis of the sensor signals. It will be appreciated that the mobile base unit may be arranged to run a software portion for receiving and processing the sensor signals and transmission of the mobile base unit signal. Such software portion is herein also referred to as BAN application framework. In the example of Fig. 1, the user network 4 comprises a back-end system 20, in this example a server, e.g. an internet server. The back-end system 20 comprises or is connected or connectable to a service receiver 22 for receiving the mobile base unit signal from the transmitter 18 of the BAN 2. In this example, the BAN 2 is connected to the UN 4 via a wireless communications link, such as GSM, GPRS, UMTS, HSDPA, EDGE, WLAN, WiMax etc.
The user network 4 further comprises computing means 24 for handling, processing and making available data associated with the mobile base unit signal to a user or users. The user network 4 in this example comprises a user group 26. In this example, the user group comprises a plurality of user terminals 28. k (k=l,2,...). A first user terminal 28.1 may e.g. belong to a medical specialist, and a second user terminal 28.2 may e.g. belong to a general practitioner. A third user terminal 28.3 may e.g. belong to a system administrator for remotely (initially) setting and or modifying a configuration of the mobile base unit 12. The user terminal may e.g. be a general-purpose computer such as a desktop computer, laptop computer, PDA, etc., a communications device, such as a mobile telephone, or a dedicated device. In this example, the user terminals 28.k are communicatively connected to the back-end system 20 via the internet using wired or wireless telecommunications connections. It will be appreciated that at least one of the user terminals may also be communicatively connected to the back-end system 20 via an intranet or using wired or wireless telecommunications connections. Alternatively, at least one of the user terminals may be integral with the back- end system, e.g. the server 20, or comprise the functionality of the back-end system 20.
Up to this point, communication of data from the mobile sensor system 6.i towards the user terminal 28.k has been described. According to an aspect of the invention, it may also be possible to send data from the user terminal 28. k towards the sensor system 6.i. Thereto, the back-end system 20 may comprise or be connected or connectable to a transmitter, or the receiver 22 may be designed as a transceiver 22, for transmitting a back-end system signal. The mobile base unit 12 may comprise a receiver, or the transmitter 18 may be designed as a transceiver 18, for receiving the back-end system signal. The mobile base unit 12 may comprise a transmitter, or the receiver 14 may be designed as a transceiver 14, for transmitting a mobile-base-unit-to-sensor- system signal. At least one of the mobile sensor systems 6.i may comprise a receiver, or the associated transmitter 10. i may be designed as a transceiver 10. i, for receiving the mobile-base-unit-to-sensor-system signal.
In the example of Fig. 1, the third mobile sensor system 6.3 comprises an actuator 30 for making information associated with a secondary mobile-base-unit-to-sensor-system signal received by the transceiver 10.3 known to the patient. The actuator 30 may comprise visual signalling means, such as a light and/or a readable and/or graphic display, auditory signalling means, such as a loudspeaker, and/or tactile signalling means, such as a vibratory element. It will be appreciated that the actuator may also perform an action in reaction to a certain mobile-base-unit-to-sensor-system signal received by the transceiver 10.3, wherein this action may be noticeable or not noticeable to the patient. It is for instance possible that the actuator actuates an insulin pump implanted in the patient in reaction to receiving a certain mobile-base- unit-to-sensor-system signal.
It will be appreciated that transmission of a signal in the direction from the user network 4 towards the Body Area Network 2 may be initiated at any stage of the system. It is for instance possible that the user enters a command into the user terminal 28.k which command is translated into a particular user command signal, which is transmitted towards the transceiver 18 of the BAN 2. It is also possible that the back-end system 20 initiates the back-end system signal, e.g. a back-end system command signal, being transmitted towards the transceiver 18, e.g. in response to certain data being received from the BAN 2. It is also possible that the data processor 16 initiates a data processor command signal being transmitted towards the actuator 30, e.g. in response to certain data being received from at least one of the mobile sensor devices 8.j, or in response to an action or input of the patient with respect to the mobile base unit. Thus, the monitoring system 1 allows diverse feedback loops to be created and/or operated within the system.
According to an aspect of the invention, in the example of Fig. 1, the mobile base unit 12 is arranged to receive sensor signals from different types of mobile sensor systems 6.i (this may also entail mobile sensor systems 6.i of different manufacturers and/or employing different data formats) and to process the data associated with the different sensor signals in a similar, or same, manner. Thereto, the mobile base unit 12 is arranged to convert the received sensor signals, or the sensor data contained in these sensor signals, into sensor channels with a preferably uniform format.
The mobile base unit 12 is arranged to receive the first sensor signal from the first mobile sensor system 6.1 and to decompose the first sensor signal, or the sensor data associated with the first sensor signal, into sensor channels, such that each sensor channel is associated with data measured by one of the mobile sensor devices 8.1, 8.2 of the first mobile sensor system 6.1. This is diagrammatically shown in Fig. 2. In the example shown in Fig. 2, the mobile base unit 12 receives the wireless sensor signal in the form of a composite sensor signal Sc from the first mobile sensor system 6.1. It will be appreciated that the composite sensor signal Sc may be formed by the first sensor signal comprising composite sensor data. The transceiver 14 forwards the received composite sensor signal Sc to the data processing means 16. In the example of Fig. 2, the data processing means 16 comprises a conversion module 32 that is arranged to decompose the composite sensor signal S0 received from the first mobile sensor system 6.1 into separate sensor signals S1 and S2 of the mobile sensor devices 8.1 and 8.2, respectively. It will be appreciated that it is also possible that the conversion module 32 is arranged to decompose the composite sensor data dc associated with the composite sensor signal S0 into separate sensor data sets di, d2 each associated with a respective one of the mobile sensor devices 8.1 and 8.2, respectively. The separate sensor signals S1 and S2 (or separate sensor data sets di, d2) are forwarded to data sorter 34. In this example, the conversion module 32 converts the sensor signals S1 and S2 (or separate sensor data sets di, d2) in a uniform data format that is readily processable by the data sorter 34. It will be appreciated that the data processing means may comprise similar data conversion modules 32', 32" for converting sensor signals (or data associated with these sensor signals) from further mobile sensor systems, such as the mobile sensor systems 6.2 and 6.3, respectively, in Fig. 2, into sensor signals S3,S4 (or data sets d3, d4) having the same (uniform) data format as the sensor signals S1 and S2 (or data sets di, d2). The sensor signals S1-S4 are herein referred to as converted sensor signals. The data sets di-d4 are herein referred to as converted sensor data. It will be appreciated that each data conversion module 32, 32', 32" may be implemented as a software module. Further, each data conversion module 32, 32', 32" may be arranged specifically to convert sensor signals (or sensor data) from a specific make and type of mobile sensor system. Such conversion modules may be arranged as plug-in modules in the software of the mobile base unit 12 (BAN application framework). In general it is known in the art how to implement plug-in modules.
The data sorter 34 arranges data associated with the converted sensor signals (i.e. the converted sensor data) in a data record. An example of such data record is shown in Fig. 3. For convenience of reading, the data record is shown as comprising a plurality of columns, each starting with a header. It will be appreciated that internally in a computer memory of the data processing means 16 the data record may be written in a different structure (such as a linear array of memory locations, or a plurality of partial arrays) which will not affect the function and purpose of the data record.
In Fig. 3 it can be seen that the data record comprises sensor channels CHm (m=l,2,3,...) (first column), wherein each sensor channel is associated with a separate mobile sensor device 8.j (third column) of a mobile sensor system (second column). In Fig. 3 the first mobile sensor system, e.g. mobile sensor system 6.1 in Figs. 1 and 2, is indicated by Dl, the second mobile sensor system, e.g. mobile sensor system 6.2 in Figs. 1 and 2, is indicated by D2, etc. In Fig. 3 the first mobile sensor device of the first mobile sensor system, e.g. mobile sensor device 8.1 in Figs. 1 and 2, is indicated by Dl.1, the second mobile sensor device of the first mobile sensor system, e.g. mobile sensor system 8.2 in Figs. 1 and 2, is indicated by D 1.2, etc. The fourth column of the data record of Fig. 3 comprises the converted sensor data associated with the actual converted sensor signals associated with the separate mobile sensor devices.
Thus, the data processing means 16 acts as a multiplexer that multiplexes a plurality of composite sensor signals (data) and/or separate sensor signals (data) into a single data record of converted sensor data. It will be appreciated that having the data record, wherein sensor data of possibly different origin are combined in a uniform data format that is readily processable by the data sorter 34, also provides the possibility to filter, or otherwise process, the converted sensor data within the mobile base unit 12. This may reduce the amount of data to be transmitted towards the user network 4.
It will be appreciated that the data record may also comprise one or a plurality of channels which are not associated with a mobile sensor system, but which are associated with a data source present in the mobile base unit 12. One channel, herein referred to as system status channel, may e.g. comprise a 'system ok' (e.g. battery) signal given by the mobile base unit 12 to signal to the back-end system 20 that the mobile base unit, for example the battery of the mobile base unit 12 and/or at least one of the mobile sensor systems 6.i, and/or BAN 2, is working properly. Such 'system ok' signal may e.g. be generated at predetermined time intervals by the mobile base unit.
Alternatively, or additionally, a channel of the data record may be associated with a patient action performed in relation to the mobile base unit, e.g. activating a button on the mobile base unit 12.
According to an aspect of the invention, a system management channel is specified comprising data for remote management of the mobile base unit 12. The system management channel is a separate wireless communications link between the mobile base unit 12 and the back-end system 20, independent of the wireless communications link (also referred to as data records channel) used for transmitting the data records. The system management channel may be awarded top priority over the data records channel. Hence, system management of the system is safeguarded, even in situations where the system has to communicate high volumes of data associated with received sensor signals from the mobile base unit to the user unit. The back-end system 20 may transmit a system management signal (e.g. in response to input at a user terminal 28.3) comprising data relating to instructions and/or parameters concerning operation of the mobile base unit 12 towards the mobile base unit 12 using the system management channel. The mobile base unit 12 may transmit a system management response, e.g. comprising acknowledgement of receipt of the system management signal and/or a new mobile base unit configuration, towards the back-end system 20 using the system management channel. In this example, the system management signal is also transmitted by the transceiver 22 and received by the transceiver 18, and the system management response is also transmitted by the transceiver 18 and received by the transceiver 22. It will be appreciated that the mobile base unit 12 and/or back-end system 20 may also be provided with a separate transceiver for the system management channel.
Returning to Fig. 2, the data record, or a part of the data record may be forwarded to the transceiver 18 of the mobile base unit 12 and transmitted to the transceiver 22 of the back-end system 20. Further, in Fig. 2, the mobile base unit 12 comprises a non-volatile memory 36. This may e.g. be an internal non-volatile memory of the mobile base unit 12, or e.g. a removable non-volatile memory such as a memory card, for instance of the type USB, SD, miniSD, microSD, MMC, CompactFlash type I (CF I), CompactFlash type II (CF II), Memory Stick PRO, MultiMediaCard, SmartMedia Card, Memory Stick Duo, xD-Picture Card, or Memory Stick PRO Duo. In the example of Fig. 2, the data record is integrally stored in the nonvolatile memory 36. This provides the advantage, that the data associated with the converted sensor signals may be retrieved from the memory 36, e.g. if transmission errors have occurred. As can be seen in Fig. 1 the back-end system 20 may comprise or be connected or connectable to the transceiver 22. The transceiver 22 receives the data records transmitted by the transceiver 18 of the BAN 2. The back-end system 20 may forward the data comprised in the data records to the user terminals 28.k in the user group 26, e.g. via email, SMS, MMS, or the like. It is also possible that the back-end system makes the data comprised in the data records available for the user terminals 28.k of the user group 26, for instance on a (secure) internet web-page or in a user accessible database.
It is also possible that a user terminal 28.k achieves direct communication with the transceiver 18 of the BAN 2, The user terminal 28.k may e.g. be a general purpose computer such as a desk top computer, laptop computer, PDA, etc., a communications device, such as a mobile telephone, or a dedicated device, which is provided with the transceiver 22. It this case, the user terminal may act as a display device. The mobile base unit 12 may advertise itself via transceiver 18 to the user terminal 28.k (e.g. direct communication via short range wireless communication technology). Once the user terminal 28. k discovers the mobile base unit 12, it may visualise the mobile base unit data on its own display. However, all communications involved to obtain the mobile base unit data is preferably provided by the back- end system 20. It is also possible that the user terminal 28.k achieves communication with the transceiver 18 of the BAN 2, via the back-end system 20 as depicted in Fig. 1.
It is also possible that a plurality of user terminals 28. k achieves communication with a single BAN 2. If, however, such plurality of user terminals 28.k achieves direct communication with that BAN 2, the main actions taken by the BAN 2 may be in handling communication with each of the plurality of user terminals 28. k. Hence, actions relating to data processing may be delayed or terminated due to insufficient computing power of the data processing means 16. According to an aspect of the invention, to cope with the plurality of user terminals 28,k (and optionally a plurality of mobile base units 12), the user network 4 may be arranged as a network of service providers and service consumers with a service discovery mechanism, wherein a mobile base unit broker 38 (or a plurality of such brokers) act as a service provider whose services are discovered and consumed by the service consumers, here the user terminals 28.k, e.g. utilizing Jini Network Technology (as developed by Sun Microsystems, Inc.) which is known per se. In the Jini model each service provider, in this case the mobile base unit broker 38, registers a Service Proxy 40 into a Jini LookUp Service 42 of a Jini network community 44, which may then be discovered and consumed by the service consumers, in this case the user terminals 28.k. Additionally, to cope with the volatile nature of the connection between mobile base units 12 and their brokers 38, a model such as the Jini Surrogate Architecture (also developed by Sun Microsystems, Inc. and known per se) can be applied, wherein the mobile base unit broker 38 takes the role of a surrogate object, a representative of a resource -constrained mobile base unit 12 on a more powerful computing platform (in this case the server 20), which monitors mobile base unit 12 liveness and hides transient failures from the users 28.k.
In the example of Figs. 1 and 2 the transmitters 10.1, 10.2, 10.3 are arranged to continuously transmit their respective sensor signals. This may pose a problem with time synchronisation of sensor signals associated with the parameters detected by the mobile sensor devices 6.1, 6.2, 6.3.
According to an aspect of the invention, the data sorter 34 is arranged to add data associated with the converted sensor signals, i.e. converted sensor data, into a first data record during a first predetermined period of time, for instance one second. After expiry of the first predetermined period of time, the first data record is closed, a unique timestamp, preferably associated with a time of generating or closing the data record, may be added, and the first data record is forwarded to the transceiver 18 for transmission. Data associated with subsequently received converted sensor signals is added into a second data record during a second predetermined period of time, preferably equally long (e.g. one second). After expiry of the second predetermined period of time the second data record is closed, a unique timestamp may be added, and the second data record is forwarded to the transceiver 18 for transmission, and subsequent data added into a third data record etc. Thus, sensor signals from different mobile sensor devices 6.i, but received by the mobile base unit 12 within the same predetermined period of time, are bundled in a data record, e.g. with the unique timestamp, and transmitted to the back-end system 20 simultaneously. Hence, the non- synchronised sensor signals, and the associated sensor data, are synchronised in the data records. It will be appreciated that the time duration of the predetermined period can be varied to achieve a desired accuracy of time synchronisation.
In Fig. 3, the amount of data associated with the respective converted sensor signals is schematically shown in the fourth column. A larger number of crosses denote a larger amount of data. It can be seen that not each mobile sensor device 8.j may deliver the same amount of data during the predetermined period of time. It will be appreciated that the differing amount of data per channel does not affect the synchronisation of the channels within the accuracy of the predetermined period of time.
Up to this point, it has been assumed that the transceiver 18 of the BAN 2 continuously transmits data records associated with sensor signals. Hence, the system 1 can be operated real-time, i.e. any given sensor signal is received by the back-end system 20 approximately at the time it is generated by the associated mobile sensor device 8.j, allowing some time delay due to processing of the signals and/or associated data, formatting of the data records etc.
It has also been explained that the data records are stored in the non- volatile memory 36 of the mobile base unit 12. Hence, it will be appreciated that the system 1 can also be operated off-line, i.e. the data record history may be accessed at will in the non-volatile memory 36.
According to an aspect of the invention it is also possible to operate the system near-line; i.e. predetermined time delayed operation. In this near- line mode of operation, the data records are stored in the memory 36 of the mobile base unit 12, and at predetermined time intervals, e.g. chosen between 300-900 seconds, a collection of data records, aggregated during the last predetermined time interval, is sent to the back-end system 20 in a single batch. This may reduce average overall transmitting time, hence improving battery life, of the mobile base unit 12, and may reduce costs associated with transmitting data via the wireless communications link to the back-end system 20, e.g. costs associated with a subscription to such a wireless communications link.
According to an aspect of the invention it is also possible to prioritise data comprised in the data records. It is for instance possible to rank channels in the data record according to their relevance for the user. In the example of Fig. 3 the fifth column displays such priorities Pm, wherein Pl denotes a higher priority than P2, which in turn denotes a higher priority than P3, etc. This allows for selective transmission of parts of the data record. This may be useful e.g. to minimise the amount of data to be transmitted. It is possible to refrain from transmitting a certain channel CHm if it is not required that the associated converted sensor data is available realtime or near-line. It may suffice that that sensor data may be retrieved from the memory 36 off-line. Hence, the transmitted data record transmitted by the transceiver 18 may differ from the stored data record stored into the memory 36.
According to an aspect of the invention, the data processing means 16 may be arranged to automatically modify the content of the data record to be transmitted (preferably without affecting the content of the data record to be stored into the memory 36) e.g. based on the perceived bandwidth of the wireless communications link. A decrease in bandwidth may e.g. be perceived by the mobile base unit 12 by an increase of a filling degree of a transmission buffer comprising data records to be transmitted by the transceiver 18. Conversely, an increase in bandwidth may e.g. be perceived by the mobile base unit 12 by a decrease of the filling degree of the transmission buffer. In this example, the transmission buffer is a buffer of the mobile base unit 12 that is located downstream of the multiplexer which multiplexes the plurality of composite sensor signals (or composite sensor data) and/or separate sensor signals (or separate sensor data) into the single data record of converted sensor data. Alternatively, or additionally, wireless communications link characteristics, such as a bandwidth, or change in these characteristics may be communicated to the mobile base unit 12 by the back-end system 20 via the data records channel and/or the system management channel.
Thus, when e.g. high bandwidth is perceived, a data record may be transmitted comprising more channels than a data record transmitted when low bandwidth is perceived. The data processing means 16 modifies the content of the data record using the priorities Pm. Hence, channels being awarded a low priority may be removed from the data record to be transmitted in order to reduce the size of the data record to be transmitted, to allow more data records per unit time to be transmitted in case of lower bandwidth. Alternatively, or additionally an amount of filtering or data compression applied to converted sensor data of a channel may be modified on the basis of the perceived wireless communications link characteristics, e.g. bandwidth. It is for instance possible to increase data filtering when lower bandwidth is perceived. It will be appreciated that it is also possible that the amount of filtering applied to converted sensor data of a channel may be modified on the basis of the perceived wireless communications link characteristics and the priority Pm of a channel. Thus, increased data filtering may be applied to channels of lower priority. It will be appreciated that a predetermined filling degree of the transmission buffer may initiate modification of the content of data records, e.g. by omission of certain channels and/or modification of the degree of filtering. It will also be appreciated that a plurality of threshold level filling degrees may be defined, wherein each threshold defines a certain level of modification of the content of the data records. It may be noted here, that the system management channel may be given a higher priority than the data records channel, so that in case of highly limited bandwidth, at least the correct system management and functioning of the BAN 2 is safeguarded. This may e.g. be used to prevent detaching of BAN 2 as the service provider from the Jini network community if the Jini surrogate architecture is used. Preferably, the rules determining how to modify the content of the data record (in the data records channel) to be transmitted based on the filling degree of the buffer can be configured.
According to an aspect of the invention, it is possible to transmit (sensor) data not previously transmitted upon request or when triggered by a special event. Such data may e.g. comprise data channels not previously transmitted, e.g. due to low bandwidth and/or low priority. Such event may e.g. be a clinical episode of a patient carrying the BAN 2. When the patient has such clinical episode, for instance recognised by at least one of the mobile sensor devices 8.j, or recognised by the patient himself and indicated by pressing the event button 8.4, the mobile base unit may continue to transmit data records comprising real-time measurement data generated by the mobile sensor devices 8.j. In case of the clinical episode, the user, in this example the physician, may want to possess historical data, not previously transmitted to the back-end system 20, of e.g. the last five minutes before the onset of the episode. The mobile base unit 12 is thereto arranged to transmit the historical data, for instance interleaved or transmitted prior to the data records of the real-time measurement data transmitted during the episode. Alternatively, or additionally, the historical data may be transmitted after the end of the episode.
It is possible that the processing means 16 of the mobile base unit 12 comprise software portions arranged for performing actions on the basis of the converted sensor data. It is for instance possible that software portions are present for making at least one of the converted sensor data known to the patient or user. It is for instance possible that such sensor data is shown, e.g. on the display of the mobile base unit 12, e.g. in the form of a numerical value, a histogram, a graph, a time line etc.
According to an aspect of the invention, the converted sensor signals, or the converted sensor data associated with the converted sensor signals are made available to a user interface using an Application Programming Interface (API). Thus, the user interface of the mobile base unit may be designed as a software portion that is separate from the BAN application framework. Using the API allows the user interface to be tailor made to the needs of a specific patient or user, without having to modify the BAN application framework. This also allows user interfaces to be manufactured by third party manufacturers. It will be appreciated that input from the user interface to the BAN application framework may also be made available using an Application Programming Interface. In a preferred embodiment, communication between the BAN application framework and the user interface makes use of Internet Protocol (IP). Hence, IP communication is used within the mobile base unit 12, between the BAN application framework and the user interface.
The invention is by no means limited to the above example. It will be appreciated that various modifications may be made without diverting from the invention.
It is for instance possible that BAN 2 is carried by an animal, in order to remotely monitor parameters of the animal.
It is also possible that the body area network is carried by a device, such as a vehicle, e.g. an automobile. In this case, the mobile sensor devices may sense parameters of certain components of the vehicle, such as tire pressure, oil pressure, engine temperature, battery voltage etc.
Within this specification a "patient" is to be understood as a person to be monitored. A patient herein thus need not have a disorder. It will be appreciated that it is also possible to monitor healthy people, for instance healthy people who require special attention, such as sportsmen, elderly or infants.