WIRELESS CONNECTIONS BETWEEN DEVICES OF MOTION TRACKING SYSTEM AND AUTHENTICATION OF A USER THEREOF

Abstract

A method for establishing wireless communications connections between sensors and a computing apparatus of a motion tracking system include the steps: processing radiofrequency signals received by the computing apparatus and transmitted by each sensor, each radiofrequency signal including an advertisement package of the respective sensor; providing a number of RSSI per sensor based on the processed radiofrequency signals; computing and storing mean RSSI values based on the number of RSSI so that a number of RSSImean values is computed per sensor; computing velocities of change of RSSImean, vRSSI, based on the number of RSSImean values so that a number of vRSSI values is computed per sensor; establishing the wireless communications for which at least the following is fulfilled: the computing apparatus determines that at least some vRSSI values within a first period of the number of vRSSI values of each sensor has a modulus greater than a predetermined minimum velocity.

Claims

1. A method for establishing wireless communications connections between a plurality of sensors of a motion tracking system and a computing apparatus of the motion tracking system, each sensor being adapted for arrangement on a body of the user, the method including the following steps: processing, by the computing apparatus, radiofrequency signals received by the computing apparatus and transmitted by each sensor of the plurality of sensors, each radiofrequency signal including an advertisement package of the respective sensor; providing, by the computing apparatus, a plurality of received signal strength indicators, RSSI, per each sensor of the plurality of sensors based on the processed radiofrequency signals; computing and storing, by the computing apparatus, mean RSSI values, RSSI.sub.mean, based on the pluralities of RSSI so that a plurality of RSSI.sub.mean values is computed per sensor; computing, by the computing apparatus, velocities of change of RSSI.sub.mean, v.sub.RSSI, based on the pluralities of RSSI.sub.mean values so that a plurality of v.sub.RSSI values is computed per sensor; and establishing, by the computing apparatus, the wireless communications connections between the computing apparatus and a set of sensors of the plurality of sensors for which at least the following is fulfilled: the computing apparatus determines that at least some v.sub.RSSI values within a first time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors has a modulus greater than a predetermined minimum velocity; wherein the predetermined minimum velocity is equal to or greater than zero.

2. The method of claim 1, wherein the connections are established between the computing apparatus and the set of sensors for which the computing apparatus determines that some v.sub.RSSI values of each sensor of the set of sensors are greater than the predetermined minimum velocity.

3. The method of claim 1, wherein the connections are established between the computing apparatus and the set of sensors whereby: the computing apparatus determines that one or more v.sub.RSSI values within a second time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors are within a predetermined velocity range; and the computing apparatus determines that the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values are greater than a predetermined motionless threshold; wherein the predetermined velocity range at least comprises a value of zero.

4. (canceled)

5. The method of claim 3-4, wherein when the set of sensors comprises a number of sensors greater than a number of wireless communications connections that the computing apparatus established, the computing apparatus establishes connections with the sensors of the set of sensors having the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values that have a smallest difference with respect to the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values of other sensors of the set of sensors.

6. The method of claim 1, further comprising after establishing the connections, not establishing, by the computing apparatus, any wireless communications connections between the computing apparatus and sensors different from those of the set of sensors until the established connections are first terminated.

7. The method of claim 1, further comprising not establishing, by the computing apparatus, wireless communications connections between the computing apparatus and one or more sensors of the plurality of sensors for which at least one of the criteria for establishing the wireless communications connections is not fulfilled.

8. The method of claim 1, further comprising, after establishing the connections: processing, by the computing apparatus, radiofrequency signals received by the computing apparatus and transmitted by each sensor of the set of sensors when the wireless communications connections are established, each radiofrequency signal including first identification data of the respective sensor; processing, by the computing apparatus, the first identification data of the radiofrequency signals; and one of: authenticating the user, by the computing apparatus, when the processed respective first identification data for all sensors of the set of sensors match or cooperate with corresponding second identification data for each respective sensor, the corresponding second identification data being stored in or being digitally accessible by the computing apparatus together with identification data of the user; and terminating, by the computing apparatus, the wireless communications connections between the computing apparatus and all the sensors of the set of sensors when the processed respective first identification data of at least one sensor of the set of sensors does not match or cooperate with corresponding second identification data for the respective at least one sensor.

9.-10. (canceled)

11. The method of claim 8, further comprising, after authenticating the user, at least one of: retrieving, by the computing apparatus, a routine of exercises to be performed by the authenticated user; and processing, by the computing apparatus, radiofrequency signals received by the computing apparatus and transmitted by each sensor of the plurality of sensors when the user is authenticated such that measurements included in the said radiofrequency signals are processed in order to provide a motion sequence of the user.

12.-15. (canceled)

16. A data processing apparatus adapted to at least wirelessly receive radiofrequency signals, the data processing apparatus comprising at least one processor adapted to at least perform; processing radiofrequency signals received by the data processing apparatus and wirelessly transmitted by each sensor of a plurality of sensors, each sensor comprising one or more of: an accelerometer, a gyroscope and a magnetometer, wherein each radiofrequency signal includes an advertisement package of the respective sensor; providing a plurality of received signal strength indicators, RSSI, per each sensor of the plurality of sensors based on the processed radiofrequency signals; computing and storing mean RSSI values, RSSI.sub.mean, based on the pluralities of RSSI so that a plurality of RSSI.sub.mean values is computed per sensor; computing velocities of change of RSSI.sub.mean, v.sub.RSSI, based on the pluralities of RSSI.sub.mean values so that a plurality of v.sub.RSSI values is computed per sensor; and establishing wireless communications connections between the data processing apparatus and a set of sensors of the plurality of sensors for which at least the following is fulfilled: the at least one processor determines that at least some v.sub.RSSI values within a first time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors has a modulus greater than a predetermined minimum velocity, wherein the predetermined minimum velocity is equal to or greater than zero.

17. The data processing apparatus of claim 16, wherein the connections are established between the data processing apparatus and the set of sensors for which the following is further fulfilled: the at least one processor determines that the some v.sub.RSSI values of each sensor of the set of sensors are greater than the predetermined minimum velocity.

18. The data processing apparatus of claim 16, wherein the connections are established between the data processing apparatus and the set of sensors for which the following is further fulfilled: the at least one processor determines that one or more v.sub.RSSI values within a second time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors are within a predetermined velocity range; and the at least one processor determines that the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values are greater than a predetermined motionless threshold; wherein the predetermined velocity range at least comprises a value of zero.

19. The data processing apparatus of claim 18, wherein when the set of sensors comprises a number of sensors greater than a number of wireless communications connections that the data processing apparatus can have established, the at least one processor establishes connections with the sensors of the set of sensors having the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values that have a smallest difference with respect to the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values of other sensors of the set of sensors.

20. The data processing apparatus of claim 16, wherein the at least one processor is adapted to at least further perform: after establishing the connections, not establishing any wireless communications connections between the data processing apparatus and sensors different from those of the set of sensors until the established connections are first terminated.

21. The data processing apparatus of claim 16, wherein the at least one processor is adapted to at least further perform: not establishing wireless communications connections between the data processing apparatus and one or more sensors of the plurality of sensors for which at least one of the criteria for establishing the wireless communications connections is not fulfilled.

22. The data processing apparatus of claim 16, wherein the at least one processor is adapted to at least further perform, after establishing the connections: processing radiofrequency signals received by the data processing apparatus and transmitted by each sensor of the set of sensors when the wireless communications connections are established, each radiofrequency signal including first identification data of the respective sensor; processing the first identification data of the radiofrequency signals; and one of: authenticating the user when the processed respective first identification data for all sensors of the set of sensors match or cooperate with corresponding second identification data for each respective sensor, the corresponding second identification data being stored in or being digitally accessible by the at least one processor together with identification data of the user; and terminating the wireless communications connections between the data processing apparatus and all the sensors of the set of sensors when the processed respective first identification data of at least one sensor of the set of sensors does not match or cooperate with corresponding second identification data for the respective at least one sensor.

23. The data processing apparatus of claim 22, wherein the at least one processor is adapted to at least further perform, after authenticating the user, at least one of: retrieving a routine of exercises to be performed by the authenticated user; and processing radiofrequency signals received by the data processing apparatus and transmitted by each sensor of the plurality of sensors when the user is authenticated such that measurements included in the said radiofrequency signals are processed in order to provide a motion sequence of the user.

24. A non-transitory computer-readable medium comprising instructions which, when executed by a device, cause the device to at least carry out the following: processing radiofrequency signals received by the device and wirelessly transmitted by each sensor of a plurality of sensors, each sensor comprising one or more of: an accelerometer, a gyroscope and a magnetometer, wherein each radiofrequency signal includes an advertisement package of the respective sensor; providing a plurality of received signal strength indicators, RSSI, per each sensor of the plurality of sensors based on the processed radiofrequency signals; computing and storing mean RSSI values, RSSI.sub.mean, based on the pluralities of RSSI so that a plurality of RSSI.sub.mean values is computed per sensor; computing velocities of change of RSSI.sub.mean, v.sub.RSSI, based on the pluralities of RSSI.sub.mean values so that a plurality of v.sub.RSSI values is computed per sensor; and establishing wireless communications connections between the device and a set of sensors of the plurality of sensors for which at least the following is fulfilled: the device determines that at least some v.sub.RSSI values within a first time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors has a modulus greater than a predetermined minimum velocity, wherein the predetermined minimum velocity is equal to or greater than zero.

25. The non-transitory computer-readable medium of claim 24, wherein the instructions cause the device to establish the connections between the device and the set of sensors for which the following is further fulfilled: the device determines that the some v.sub.RSSI values of each sensor of the set of sensors are greater than the predetermined minimum velocity.

26. The non-transitory computer-readable medium of claim 24, wherein the instructions cause the device to establish the connections between the device and the set of sensors for which the following is further fulfilled: the device determines that one or more v.sub.RSSI values within a second time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors are within a predetermined velocity range; and the device determines that the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values are greater than a predetermined motionless threshold; wherein the predetermined velocity range at least comprises a value of zero.

27. The non-transitory computer-readable medium of claim 25, wherein when the set of sensors comprises a number of sensors greater than a number of wireless communications connections that the device can have established, the device establishes connections with the sensors of the set of sensors having the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values that have a smallest difference with respect to the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values of other sensors of the set of sensors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] To complete the description and in order to provide for a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate embodiments of the invention, which should not be interpreted as restricting the scope of the invention, but just as examples of how the disclosure can be carried out. The drawings comprise the following figures:

[0087] FIG. 1 diagrammatically shows a motion tracking system in accordance with embodiments.

[0088] FIG. 2 shows a motion tracking system with sensors thereof arranged on a person that is the user thereof.

[0089] FIGS. 3A and 3B diagrammatically show a plurality of sensors of a motion tracking system prior to establishment of wireless communications connections in accordance with embodiments.

[0090] FIGS. 4A-4C and 5A-5C show graphs with examples of RSSI, RSSI.sub.mean and v.sub.RSSI computed by computing apparatuses in accordance with embodiments.

[0091] FIG. 6 shows a graph corresponding to some curves of FIGS. 5B and 5C with requirements to be met for establishing connections in accordance with embodiments.

[0092] FIG. 7 diagrammatically shows methods in accordance with embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS

[0093] FIG. 1 diagrammatically shows a motion tracking system 5 in accordance with embodiments. The motion tracking system 5 includes a plurality of sensors 20a-20n and a computing apparatus 10, which may be e.g. a tablet, a mobile phone, a personal computer, etc.

[0094] Each sensor 20a-20n is adapted to be arranged on the body of a user so that the measurements provided by each sensor 20a-20n can be processed by the computing apparatus 10, thereby providing a motion sequence of the user. Each sensor 20a-20n is an inertial measurement unit that includes one or more sensing devices selected from e.g. an accelerometer 21, a gyroscope 22 and a magnetometer 23. In the embodiment of FIG. 1, each sensor 20a-20n includes all three sensing devices 21-23, but in other embodiments the sensors only include an accelerometer 21 and a gyroscope 22, for instance. Preferably, all sensors 20a-20n include the same sensing devices 21-23.

[0095] The sensors 20a-20n further include at least one processor 26, at least one memory 27, and a first communications module 28 for transmitting radiofrequency signals to the computing apparatus 10 and which include e.g. advertisement packages, data packets with identification data (e.g. one or more identities, keys, etc.), data packets with measurements of the sensing device(s) 21-23, etc. When no wireless communications connections are established with the computing apparatus 10, the radiofrequency signals of the sensors 20a-20n include advertisement packages for indicating their presence and that they are active. Once the wireless communications connections are established (using a technology and protocol known by a skilled person, for instance but without limitation, Bluetooth and Bluetooth Low Energy communications, cellular network communications such as GSM, UMTS or LTE, wireless LAN communications, etc.) with the computing apparatus 10, the radiofrequency signals of the sensors 20a-20n may include identification data and/or the measurements. An antenna for radiating electromagnetic waves is provided as part of the first communications module 28. The same first communications modules 28, preferably, also enables the sensors 20a-20n to receive data from the computing apparatus 10 upon capturing electromagnetic waves with the antenna.

[0096] In some preferred embodiments, the at least one processor 26 of the sensors 20a-20n runs a sensor fusion algorithm for processing the measurements of the sensing devices 21-23 within the respective sensor. The sensor fusion algorithm is intended to enhance the raw measurements of the sensing devices by correcting errors thereof due to drifts of the sensing devices and, thus, outputs processed measurements that are to be transmitted to the computing apparatus 10.

[0097] The computing apparatus 10 includes at least one processor 11, at least one memory 12, and a second communications module 13 for at least receiving data. The second communications module 13 includes at least one antenna whereby electromagnetic waves may be captured, and then processed by the at least one processor 11.

[0098] The computing apparatus 10 preferably also includes at least one sensor 14 with one or more sensing devices like an accelerometer, a gyroscope and/or a magnetometer, and a screen 15. On said screen 15 the computing apparatus 10 is capable of showing instructions and/or information to the intended user about the wireless connection process. Likewise, the computing apparatus 10 may use the screen 15 in order to show the movements that are to be performed by an intended user of the motion tracking system 5 and feedback on the movements performed by the intended user during the motion tracking procedure. To this end, the computing apparatus 10 stores, in the at least one memory 12, data indicative of a correspondence between sensors and users assigned to those sensors, and also data relative to the physical exercises of intended users. Any of these data can be transmitted to and/or received from another electronic device thanks to the second communications module 13. For example, a therapist is able to receive the feedback at a computing apparatus in a hospital so as to monitor the evolution of the person. Based on the feedback received, the therapist is able to adjust the difficulty of the movement(s), the number of repetitions thereof, prescribe new movements, etc. so that the person may further exercise using the motion tracking system 5. Further, in addition to the screen 15, which provides visual feedback, the computing apparatus 10 may also include further visual output means (e.g. LEDs, animations), audio output means (e.g. loudspeakers), vibrating means (e.g. a vibrator), etc. for providing user perceptible signals in the form of sounds, vibration, animated graphics, etc.

[0099] FIG. 2 shows a motion tracking system with sensors 20a-20c thereof arranged on a person that is the user 1 thereof.

[0100] The user 1 has a first sensor 20a attached to the right upper arm, a second sensor 20b attached to the right lower arm, and a third sensor 20c attached to the chest. The sensors 20a-20c may be attached to the body of the user 1 in a number of ways, for instance using straps, Velcro, etc.

[0101] At a distance from the user 1 is a computing apparatus 10 of the motion tracking system that is to process measurements of the sensors 20a-20c in order to provide the motion sequence of the user 1.

[0102] Each of the sensors 20a-20c provides radiofrequency signals by radiating electromagnetic waves 29a-29c whenever the sensors are transmitting data packets, which in turn are captured by the computing apparatus 10.

[0103] FIG. 3A diagrammatically shows a plurality of sensors of a motion tracking system prior to establishment of wireless communications connections, and FIG. 3B shows the same but with the movement of one of the users 1a-1c.

[0104] A plurality of sensors 20 (illustrated as magnified squares for the sake of clarity only) of a motion tracking system 5 that, for example, define N sets of sensors 30a-30n is active. For example, a first set of sensors 30a is on a table, a second set of sensors 30b is being worn by a first user 1a, a third set of sensors 30c is being carried by a second user 1b in a hand thereof, and an n-th set of sensors 30n is being carried by an m-th user 1m in a hand thereof.

[0105] The sensors 20 of each of these sets 30a-30n may be active but not connected with the computing apparatus 10 but with other computing apparatuses, or not connected with any computing apparatus at all. The sensors 20 may also be transmitting radiofrequency signals with advertisement packages therein for informing of their presence to other devices. The computing apparatus 10 receives, for example, electromagnetic waves of up to sixteen different sensors and cannot determine which of the sensors, if any, is to be used in a motion tracking procedure.

[0106] The computing apparatus 10 processes the captured electromagnetic waves in order to provide received signal strength indicators per sensor, which can be stored in a memory of the computing apparatus 10 along with a timestamp indicating when the radiofrequency signal was processed. The apparatus 10 can establish to which sensor each RSSI corresponds by way of the information contained in the advertisement packages, which indicates a public identity of the sensor it transmitted the advertisement package. Then, the computing apparatus 10 averages the RSSI of each sensor in order to provide mean received signal strength indicators per sensor, and stores them along with a timestamp indicating when the RSSI.sub.mean was computed. The computing apparatus 10 computes velocities of change of the RSSI.sub.mean per sensor to determine how its RSSI.sub.mean is evolving over time.

[0107] In FIG. 3B, the second user 1b is moving (as illustrated with the arrow) such that a distance of the set of sensors 30c thereof to the computing apparatus 10 changes, thereby changing the RSSI computed by the computing apparatus 10 upon reception of the radiofrequency signals transmitted while the second user 1b is moving. Based on the velocities of change of the RSSI.sub.mean, the computing apparatus 10 may establish that the sensors 20 of the third set of sensors 30c is to be connected thereto and not the sensors 20 of the first, second and n-th sets of sensors 30a, 30b, 30d, whose velocities of change of the RSSI.sub.mean is substantially zero owing to the little or no movement at all to get closer to or farther away from the computing apparatus 10.

[0108] FIGS. 4A, 4B and 4C show the evolution over time of RSSI values, RSSI.sub.mean values, and v.sub.RSSI values, respectively, of six sensors.

[0109] For the sake of clarity only, the curves 50, 51, 60, 61, 70, 71 of two sensors of one set (e.g. first set) are shown with solid lines, the curves 52, 53, 62, 63, 72, 73 of two sensors of another set (e.g. second set) are shown with long-dash lines, and the curves 54, 55, 64, 65, 74, 75 of two sensors of yet another set (e.g. third set) are shown with short-dash lines. It is noted that the computing apparatus does not know which sensors belong to which set, this is only described in this manner for the sake of a clearer explanation only. Likewise, it is noted that even though curves are shown, these are only shown only for the sake of clarity, what the computing apparatus receives is discrete data packets (shown with circles and triangles) and usually not equally spaced in time since. Accordingly, the RSSI values are obtained upon receiving the packets, which are transmitted by the sensors at discrete times.

[0110] As it can be seen, the RSSI values 50-51, 54-55 of the sensors of the first and third sets do not change much over time, yet the RSSI values 52-53 of the second set increases during a time period. The value of the RSSI 50-55 can usually be correlated with the distance between the transmitting devices and the receiving device. In this sense, if for example the scenario of FIGS. 3A and 3B is considered, the sensors of the first set can be some sensors of the first user 1a, the sensors of the second set can be some sensors of the second user 1b, and the sensors of the third set can be some sensors of the m-th user 1m.

[0111] The RSSI.sub.mean values smooth the RSSI values and compensate for any spontaneous RSSI changes due to sporadic interferences for instance.

[0112] The v.sub.RSSI values are computed by deriving the RSSI.sub.mean values and show the variation thereof for all the sensors. In this case, the v.sub.RSSI values 70-71, 74-75 of both the first and third sets are zero or close to zero during the whole period of time represented in the graph, whereas the v.sub.RSSI values 72-73 of the second set are, during a period of time, greater than zero, particularly they reach a maximum value of V1.

[0113] When a computing apparatus requires that the modulus of v.sub.RSSI and, optionally, that v.sub.RSSI itself needs be greater than a predetermined minimum velocity PMV that is less than V1, then the sensors of the second set may fulfill said requirement and, thus, the computing apparatus can establish the wireless communications connections with them.

[0114] FIGS. 5A-5C show graphs analogous to those of FIGS. 4A-4C but with other exemplary behaviors of the respective sensors and, thus, of the RSSI values obtained by a computing apparatus of a motion tracking system.

[0115] In this example, according to the RSSI.sub.mean values 60-61 of R1, the sensors of the first set appear to be closer to the computing apparatus in comparison with the sensors of the other two sets. At a certain point in time, the sensors of the first set move away from the computing apparatus as illustrated by their RSSI 50-51 and RSSI.sub.mean values 60-61, but more clearly illustrated by their v.sub.RSSI 70-71 values, which are negative (reaching a minimum value of V3) during a period of time, and then become zero, which is indicative of no change in distance between the sensors and the computing apparatus.

[0116] In relation to the sensors of the second set, these sensors get closer to the computing apparatus as their v.sub.RSSI values 72-73 reach a maximum value of V1, then they remain at a substantially same distance from the computing apparatus. Later on, they get away from the computing apparatus with v.sub.RSSI values 72-73 reaching a minimum value of V2, and then they remain at a same distance from the computing apparatus.

[0117] The sensors of the third set are the ones farthest away from the computing apparatus at the beginning according to their RSSI.sub.mean values 64-65 of R5. Then, they get closer to the apparatus in a slow manner since the v.sub.RSSI values thereof 74-75 reach a value of V4 slightly above zero. Afterwards, they remain at an unvarying distance from the apparatus.

[0118] By way of example, the computing apparatus establishes wireless communications connections with sensors for which it determines that that: [0119] some v.sub.RSSI values within a first time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors are greater than the predetermined minimum velocity, e.g. zero; [0120] one or more v.sub.RSSI values within a second time period of the plurality of v.sub.RSSI values of each sensor of the set of sensors are within a predetermined velocity range, e.g. PVR with limits PVR.sub.max and PVR.sub.min; and [0121] the RSSI.sub.mean values for computing each v.sub.RSSI of said one or more v.sub.RSSI values are greater than a predetermined motionless threshold, e.g. PMT.

[0122] The first set of sensors does not have a first time period in which some v.sub.RSSI values thereof 70-71 are greater than zero, hence no connections are established with those sensors.

[0123] The second set of sensors has a first time period in which some v.sub.RSSI values thereof 72-73 are greater than zero (V1>0), has a second time period in which one or more v.sub.RSSI values thereof 72-73 are within the PVR range (e.g. at the beginning, between the periods in which the v.sub.RSSI is V1 and V2, at the end), and has the second time period in which RSSI.sub.mean values thereof 62-63 are greater than the PMT threshold (in the period between v.sub.RSSI equal to V1 and equal to V2, in which the RSSI.sub.mean is R2).

[0124] The third set of sensors has a first time period in which some v.sub.RSSI values thereof 74-75 are greater than zero (V4>0), has a second time period in which one or more v.sub.RSSI values thereof 74-75 are within the PVR range (e.g. at the beginning, at the end), and has the second time period in which RSSI.sub.mean values thereof 64-65 are greater than the PMT threshold (at the end, in which the RSSI.sub.mean is R3).

[0125] Both the second and third sets of sensors meet the requirements and, thus, the computing apparatus can establish the connections with those.

[0126] In some examples, since the sensors of the second set meet the requirements before (time-wise) the sensors of the third set, the computing apparatus establishes the connections with the sensors of the second set and does not establish any further connections, namely it does not establish connections with the sensors of the third set.

[0127] In some other examples, the computing apparatus waits a period of time for determining all the possible sensors that it can establish connections with, in this case with the second and third sets, and establishes the connections with all of them.

[0128] In both exemplary scenarios, the computing apparatus may proceed to authenticate the user once connected with the sensors. To this end, the apparatus processes the identification data sent by each sensor and authenticates the user or not based on the matching or cooperation of the identification data sent by all the sensors with corresponding identification data. For authentication of the user, all the sensors need have been assigned to the same user in e.g. a database, a server, a memory of the computing apparatus, etc.

[0129] FIG. 6 shows a graph corresponding to some curves of FIGS. 5B and 5C with requirements to be met for establishing connections in accordance with embodiments. For the sake of simplicity, the RSSI.sub.mean values 62 of a sensor of the second set are shown (with cross markers, and a solid line for the sake of clarity only) along with the v.sub.RSSI values 72 (with square markers, and a dashed line for the sake of clarity only) corresponding to the RSSI.sub.mean values 62.

[0130] In addition to the requirements set in the example described in relation to FIGS. 5A-5C, by way of another example, the wireless communications connections are established by the computing apparatus when it determines that a time elapsed between at least one pair of v.sub.RSSI of the plurality of v.sub.RSSI (of each sensor to which it is to connect to) is within a predetermined motion time range. The respective v.sub.RSSI values (i.e. the v.sub.RSSI values with the time elapsed between the predetermined motion time range) are those whose modulus or value thereof is greater than the predetermined minimum velocity as explained before. Therefore, for example in the time period T.sub.B or the time period T.sub.D, at least the time elapsed between two v.sub.RSSI values (with square markers) within such time periods (including the endpoints of the time periods T.sub.B and T.sub.D) shall fulfill: min_rssi_increase_time<Δt|.sub.vRSSI<max_rssi_increase_time. The two v.sub.RSSI values may not be consecutive but must be within the same time period; by way of example, any one of Δt.sub.1, Δt.sub.2, and Δt.sub.3 shall fulfill said requirement.

[0131] The computing apparatus can also require that a time elapsed between RSSI.sub.mean values used for computing the respective v.sub.RSSI values are within a predetermined RSSI.sub.mean time range. This means that the time elapsed shall fulfill the following relationship: min_detection_rssi_time<Δt|.sub.RSSImean<max_detection_rssi_time. The two RSSI.sub.mean values may not be consecutive but must be within the same time period; using the same Δt.sub.1, Δt.sub.2, and Δt.sub.3 depicted by way of example only, any one of Δt.sub.1, Δt.sub.2, and Δt.sub.3 shall fulfill said requirement.

[0132] It is noted that the discrete transmissions of the sensors represented in FIGS. 4A-4C, 5A-5C and 6 are transmissions before the computing apparatus has established wireless communications connections with any such sensor. Accordingly, in those discrete transmissions, the sensors include advertisement packages as known in the art for identification purposes. After establishing the connections with some sensors, the sensors may provide further transmissions with identification data thereof so that the computing apparatus is capable of authenticating the user based on the identification data.

[0133] FIG. 7 diagrammatically shows methods 100 in accordance with embodiments.

[0134] The methods 100 comprise a step 110 whereby a computing apparatus (for example, the computing apparatus 10 of any one of FIGS. 1, 2, 3A-3B) of a motion tracking system (for example, the system 5 of any one of FIGS. 1, 2, 3A-3B) processes radiofrequency signals that sensors (for example, the sensors 20, 20a-20n of FIGS. 1, 2, 3A-3B) have transmitted by way of radiated electromagnetic waves and that the computing apparatus has received upon capturing the electromagnetic waves. Each radiofrequency signal includes an advertisement package of the respective sensor.

[0135] The methods 100 also comprise a step 120 whereby the computing apparatus provides a plurality of received signal strength indicators, RSSI, per each sensor of the plurality of sensors based on the radiofrequency signals processed 110.

[0136] The methods 100 also comprise a step 130 whereby the computing apparatus both computes and stores (in a memory of the computing apparatus, or in a device not belonging to the apparatus, e.g. a server, a cloud, etc.) mean RSSI values, RSSI.sub.mean, based on the pluralities of RSSI provided 110 so that a plurality of RSSI.sub.mean values is computed and stored per sensor.

[0137] The methods 100 also comprise a step 140 whereby the computing apparatus computes velocities of change of RSSI.sub.mean, v.sub.RSSI, based on the pluralities of RSSI.sub.mean values so that a plurality of v.sub.RSSI values is computed per sensor. The v.sub.RSSI values are preferably also stored by the computing apparatus.

[0138] The methods 100 also comprise a step 150 whereby the computing apparatus establishes wireless communications connections between the computing apparatus and a set of sensors for which one or more requirements are met. When the requirements are not met, the computing apparatus does not establish the wireless communications connections and continues carrying out the above steps until the wireless connections can be established 150. In this sense, the arrow between steps 140 and 150, and between steps 140 and 110 are indicated with dashed lines to illustrate that one of the outcomes is produced each time.

[0139] The methods 100 may also comprise a step 160 after establishing 150 the wireless connections whereby the computing apparatus processes radiofrequency signals that the connected 150 sensors have transmitted by way of radiated electromagnetic waves and that the computing apparatus has received upon capturing the electromagnetic waves. Said radiofrequency signals are transmitted once the connections have been established 150 and include identification data of each respective sensor. The computing apparatus processes the identification data of the radiofrequency signals.

[0140] When the methods 100 comprise the step 160, they also comprise one or both of steps 170 and 190. In step 170, the computing apparatus authenticates a user of the set of sensors when the processed 160 identification data for the sensors of the set of sensors match or cooperate with corresponding identification data for each respective sensor that is stored in or is digitally accessible by the computing apparatus. In step 190, the computing apparatus does not authenticate the user because the identification data of the sensors does not match or cooperate with the corresponding identification data, and the computing apparatus terminates the connections established 150.

[0141] The methods 100 also comprise the step 180 whereby the computing apparatus processes radiofrequency signals that the connected 150 sensors have transmitted by way of radiated electromagnetic waves and that the computing apparatus has received upon capturing the electromagnetic waves. Said radiofrequency signals are transmitted once the connections have been established 150 and, preferably, once the user has been authenticated 170, however as shown with dashed lines, in some embodiments the steps 160, 170 and 180 are not present and the step 180 takes place after establishing 150 the wireless connections. The radiofrequency signals processed 180 by the computing apparatus include measurements of the sensors that it is connected to so that a motion sequence of the user is provided. In this sense, in step 180 the computing apparatus can retrieve a routine of physical exercises that the authenticated 170 user or the deemed user (if there is no authentication 170) of the set of sensors and be presented to the user. Likewise, the computing apparatus can register the motion sequence provided after processing 180 the measurements within the radiofrequency signal together with data indicative of the authenticated 170 user or deemed user.

[0142] The methods 100 preferably also comprise, upon finishing the motion tracking procedure carried out in step 180, a step 185 whereby the computing apparatus terminates the established 150 wireless communications connections with the sensors, thereby making possible to have the motion of other users tracked once the sensors they wear connect with the computing apparatus by way of the steps of the methods 100.

[0143] In this text, the terms first, second, third, etc. have been used herein to describe several devices, elements or parameters, it will be understood that the devices, elements or parameters should not be limited by these terms since the terms are only used to distinguish one device, element or parameter from another. For example, the first time period could as well be named second time period, and the second time period could be named first time period without departing from the scope of this disclosure.

[0144] In this text, the term “comprises” and its derivations (such as “comprising”, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc.

[0145] On the other hand, the disclosure is obviously not limited to the specific embodiment(s) described herein, but also encompasses any variations that may be considered by any person skilled in the art (for example, as regards the choice of materials, dimensions, components, configuration, etc.), within the general scope of the disclosure as defined in the claims.