Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/22—Ergometry; Measuring muscular strength or the force of a muscular blow
  • A61B5/221—Ergometry, e.g. by using bicycle type apparatus
  • A61B5/222—Ergometry, e.g. by using bicycle type apparatus combined with detection or measurement of physiological parameters, e.g. heart rate

Definitions

• the invention relates to the multiplexed unidirectional transmission of data collected from a series of individuals to a central station for analyzing this data.
• One of the aims of the invention is to propose such a system which is simple and reliable, and which in particular avoids the use of a bidirectional data link, such as a TDMA type transmission, where synchronization of data exchanges is imposed and established by a central time base: such a technique, if it is effective in terms of data transmission, however requires fairly complex means, both with regard to individual equipment and central equipment, and is in reality only justified if one wishes to organize a channel for feedback from the central station to the individual, which is not always necessary.
• the system of the invention comprises: on the one hand, individual equipment, associated with each individual, comprising means for collecting and digitizing a set of information specific to the individual, comprising at least one heart rate information and one individual identifier, and radio transmitting means, for transmitting on a common carrier frequency a data message containing said information specific to the individual, this message being transmitted asynchronously during a time slot in a data frame repeated regularly, the position of the slot in the frame being determined by random or pseudo-random drawing on each transmission; and on the other hand a remote central equipment, comprising radio receiving means, for collecting the data messages transmitted by the individual equipment and reconstructing said data frame comprising a plurality of messages relating to at least a portion of the individuals, and for forming a results frame gathering the collected information, and means of interfacing with a computer equipment, to deliver to the latter successive results frames for display and / or analysis.
• the set of information specific to the individual may also include: validity information of the heart rate information, speed information, distance traveled information, waypoint marking information and / or emergency call information.
• the ratio between the number of time slots in the data frame and the number of individuals is at least five, preferably at least ten.
• Figure 1 schematically illustrates a team of cyclists followed by the sports director's car.
• Figure 2 is a block diagram showing the main functions the transmission system according to the invention.
• Figure 3 shows the configuration of the individual equipment installed on a bicycle.
• Figure 4 is a block diagram of the data receiving circuit.
• Figure 5 shows the structure of a data frame.
• the reference 10 designates a cyclist of a team comprising several, followed by the vehicle 12 of the sports director who wishes to collect digital information from each of the riders to monitor performance and everyone's effort.
• the individual equipment 14 of each runner comprises an individual box 16 connected to a sensor 18 making it possible to collect heart rate information produced by a belt 20 fixed on the chest of the runner, and allowing wireless transmission of this information the belt to the sensor 18. More specifically, the electrocardiogram signal at the surface of the body is taken and transmitted to a cardiac rhythm calculation unit, incorporated in the belt 20, by short wired connection. The signal thus calculated, which has been possibly filtered, average, etc. modulates a VLF carrier, which is picked up by the coil 18 tuned to this carrier frequency.
• This technology is in itself known and is used for example by belts of the brand Polar, and will not be described in more detail.
• the housing 16 can for example be either fixed on the seat post, or nested inside the saddle giving it an appropriate shape, and the sensor 18 is placed either on the upper bar of the frame is an extension of the box below the saddle (as in 18 '), near the thorax, in order to minimize the distance between sensor and belt and avoid interference between the signals emitted for example by two riders finding them side by side.
• the housing 16 also receives ment of speed or distance traveled information, via a wheel signal sensor 22 receiving the signals emitted by a fork relay 24 excited by the passage of a wheel magnet 26 (of course, the connection between fork relay and case can be, more simply, a simple wired connection).
• the calculation of the speed is developed from the measurement of time, sampled with a rhythm close to 20 kHz, separating the two successive pulses from the rear wheel relay. If the corresponding relay pulse has not been received, the memorized value of the last movement detected is considered for a maximum time of 8 s.
• the input of speed information is not a limiting characteristic of the invention, and the corresponding data input could be used in different ways, for example by connecting it to a push button that the runner would activate when crossing certain remarkable points (for example circuit laps or milestones), such as emergency call, etc.
• the box 16 will thus collect heart rate information and speed or distance traveled information and will transmit these, as will be explained with reference to FIG. 5, asynchronously by radio means, for example (but of course in no way limiting) on a frequency of the order of 433 MHz, which makes it possible to be satisfied with an antenna 28 a few centimeters long, for a range of the order of 1 to 2 km in free space for 10 mW of transmit power, with fairly good immunity to noise and natural obstacles.
• radio means for example (but of course in no way limiting) on a frequency of the order of 433 MHz, which makes it possible to be satisfied with an antenna 28 a few centimeters long, for a range of the order of 1 to 2 km in free space for 10 mW of transmit power, with fairly good immunity to noise and natural obstacles.
• FIG. 4 shows in more detail the structure of the central equipment 30 , which advantageously comprises two parallel reception chains, connected to two separate antennas, in order to achieve the diversity of reception space and thus avoid any "hole" in receiving data.
• Each reception chain comprises, in addition to a receiver 34, a synchronization detection circuit 36 controlled by a synchronization pattern present in each of the received frames (see below). The detection of the synchronization pattern closes the switch 38 to allow data transmission to an error correction stage 40 and a "checksum" control stage 42, making it possible to deliver at 44 the frames received on each of the communication channels. reception.
• a circuit 46 selects, from the two frames received, the one having the best quality (absence of error), which is then transmitted to the portable computer via an interfacing circuit 48.
• the following format will now be described more precisely which data is transmitted from the riders to the following car.
• This transmission is a unidirectional asynchronous transmission of the "Slotted Aloha" type, which makes it possible to manage the possible collisions inherent in the asynchronous nature of the transmissions.
• a frame of duration equal to
• each elementary slot consisting of fifty (or, better, one hundred) "slots" or elementary time slots with cyclic occurrence, each elementary slot being composed of a phase of transmission of a radio synchronization signal for 26 ms and a phase of sending a message proper for 29.5 ms.
• each mobile randomly draws one of the fifty slots on which its message will be sent.
• the slots are distributed in a pseudo-random manner as illustrated in FIG. 5, with possible possibilities of collisions between two messages (for example the messages of the runners n ° 7 and 10 in FIG. 5).
• the probability of collision is deduced from the efficiency curve of the "Slotted Aloha” knowing the network load, the latter being determined by the simultaneous number of mobiles, the number of slots available in the frame and the asynchronism of the mobiles between them .
• the communication from the runner box to the central office typically contains:
• - cardiac rhythm information (8 bits), - valid heart rate information (1 bit): in case of non-detection of the pulse sent by the belt, the unit sends the stored value of the last heartbeat detected, with this validity indicator at '0',
• the communication uses 59 bits or 29.5 ms at 2 kbit / s.
• the parameters chosen in this example make the communication from the runner to the central very efficient.
• the probability of collision for one of these mobiles in the frame is very low.
• the speed and heart rate information therefore frequently arrive every 2.9 s at the central office and at worst every 5.8 s (the probability of two successive collisions on the message from the same mobile is very small) .
• the transmission to transmission of the box is made only at the rate of the frames, i.e. every 2.69 s, for 55.5 ms (26 ms of pure carrier to allow radio synchronization + 29.5 ms of message) or a form factor of 0.012.
• this individual box is programmable, for example by means of an RS 232 link or else using miniature switches, to configure the runner number, an encryption key, the carrier frequency channel, a operating mode (gross heart rate / average heart rate; gross speed / average speed), etc.
• the central equipment 30 can be configured beforehand by an RS 232 link: transmitter channel, encryption key, operating mode, number of runners, etc.
• the results sent by the central equipment 30 to the laptop 32 can be done through a conventional RS 232 interface at 9600 bits per second, with a result frame typically having the following format (for a total of 76 bytes ):
• This byte is strongly linked to the presence of the runner since if there is no frame reception, there is no heart rate reception; when receiving a 433 MHz frame, if the central office receives a zero heart rate (indicating that the runner module has completely picked up), this implausibility byte is then increased by 10 units.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Heart & Thoracic Surgery (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Biophysics (AREA)
• Pathology (AREA)
• Physics & Mathematics (AREA)
• Biomedical Technology (AREA)
• General Health & Medical Sciences (AREA)
• Medical Informatics (AREA)
• Molecular Biology (AREA)
• Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• Cardiology (AREA)
• Physiology (AREA)
• Physical Education & Sports Medicine (AREA)
• Computer Networks & Wireless Communication (AREA)
• Mobile Radio Communication Systems (AREA)

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• 1997
  • 1997-01-10 FR FR9700175A patent/FR2758404B1/fr not_active Expired - Fee Related
• 1998
  • 1998-01-08 WO PCT/FR1998/000026 patent/WO1998030142A1/fr not_active Application Discontinuation
  • 1998-01-08 EP EP98902043A patent/EP0959759A1/de not_active Withdrawn

Non-Patent Citations (1)

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