SE1650582A1 - Method for presence detection - Google Patents

Abstract

A method for verifying the presence of users running a status check application on their wireless transceiver units is provided. The method comprises a presence check comprising setting up a group list of wireless transceiver units specific to the status check application. Each wireless transceiver unit having a group list ID. The method further comprises broadcasting an application specific presence check signal including a command message, from the initiating wireless transceiver unit and receiving the broadcast presence check signal including the command message, at the additional wireless transceiver unit. The method further comprises listening for a broadcast presence check acknowledgement, in the initiating wireless transceiver unit using the local network transceiver, and upon receipt of a presence check acknowledgement, including the group list ID from the additional wireless transceiver unit, updating the group list by marking the additional wireless transceiver unit as present.Selected for publication: Fig. 4A"

Description

1METHOD FOR PRESENCE DETECTION Field of the invention

[0001] The invention relates to the technical field of presence detection using radio signaling between users of wireless transceivers.

Technical Background

[0002] There are numerous of situations and contexts where there is agreat value to autonomously and fast verify if members in a group are locally present and if needed locate the members in relation to the one verifying.

[0003] Traditionally this has been implemented either by manually countingand orally and visually verifying if members are presence, while for somescenarios there are dedicated technical equipment that can be used for this purpose.

[0004] Especially in situations of more critical character, various purposebuilt technological solutions has been developed to enhance or enable thedetection and location. Example of such application is avalanche rescueequipment, various military applications and GNSS (Global NavigationSatellite Systems) (e.g. GPS (Global Positioning System)) based solutionsfor keeping track and locating e.g. pets or children.

[0005] Today, mobile phone platforms enable these applications to beimplemented as software. This software approach on the advanced mobileplatforms of today enables improved usability. When combined with theconnected ability of a mobile phone, opportunities arise from bothconnecting the application with the Internet (or other services), as well asfrom a distributed model making the application instantly available to largeand broad user segments.

Summary of the invention

[0006] One aim of the present invention is to provide a method for verifyingthe presence of users running a status check application on their wirelesstransceiver units. The wireless transceiver units comprises an initiatingwireless transceiver unit having a local network transceiver and anadditional wireless transceiver unit having a local network transceiver. Themethod comprises a presence check comprising setting up, in the initiatingwireless transceiver unit, a group list of wireless transceiver units specific tothe status check application, comprising at least one additional wirelesstransceiver unit. Each wireless transceiver unit having a group list ID. Themethod further comprises broadcasting an application specific presencecheck signal including a command message, from the initiating wirelesstransceiver unit, using the local network transceiver, receiving the broadcastpresence check signal including the command message, at the additionalwireless transceiver unit, using the local network transceiver, andtransmitting a broadcast presence check acknowledgement comprising thegroup list ID, on the basis of the command message, from the additionalwireless transceiver unit, using the local network transceiver. The methodbroadcast acknowledgement, in the initiating wireless transceiver unit using the local further comprises listening for a presence checknetwork transceiver, and upon receipt, at the initiating wireless transceiverunit, of a presence check acknowledgement, including the group list ID fromthe additional wireless transceiver unit, updating the group list by marking the additional wireless transceiver unit as present.

[0007] One advantage with the presence check method is that a presencecheck can be performed using only broadcast signaling, which makes itpossible to receive a presence check signal from all wireless transceiverunits within the range of the local network transceiver. The presence checkmay also be possible without any input from the user and even if the wireless transceiver unit is buried in e.g. snow. 3

[0008] According to one embodiment the method further comprising astatus check. The status check comprises sending a status check messagefrom the initiating wireless transceiver unit, using the local networktransceiver, to at least one present additional wireless transceiver unit, andprompting a user of the at least one present additional wireless transceiverunit for positive or negative status. Upon receipt of a positive status input inthe at least one present additional wireless transceiver unit, the additionalwireless transceiver unit transmits a positive status check messageacknowledgement, and upon receipt of a negative status input in the at leastone present additional wireless transceiver, or in the absence of a statusinput, the additional wireless transceiver unit transmits a negative statuscheck message acknowledgement. The method further comprises the stepof listening for status check message acknowledgements from the at leastone present additional wireless transceiver unit, at the initiating wirelesstransceiver unit, and upon receipt of a positive status check messageacknowledgement, at the initiating wireless transceiver unit, from the at leastone present additional wireless transceiver unit, updating the group list bymarking the at least one present additional wireless transceiver unit as ok,and upon receipt of a negative status check message acknowledgement, orin the absence of a status check message acknowledgement, from the atleast one present additional wireless transceiver unit, updating the group listin the initiating wireless transceiver unit by marking the at least one present additional wireless transceiver unit as not ok.

[0009] The status check method makes it possible to determine the statusof the present wireless transceiver units using broadcasting signaling, whichfor example means that the method can be performed without the wirelesstransceiver units having cell phone coverage.

[00010]According to one embodiment, the method further comprisesinitiating a search procedure for at least one present additional wirelesstransceiver unit marked as not ok. The search procedure comprising 4 listening, at the initiating wireless transceiver unit, for signaling from the atleast one present additional wireless transceiver unit marked as not ok,determining, at the initiating wireless transceiver unit, the signal strengthreceived from the at least one present wireless transceiver unit marked asnot ok, and using the determined signal strength for determining the locationof the at least one present wireless transceiver unit marked as not ok, at the initiating wireless transceiver unit. [0001 1] The search procedure enables the searching to be performed by allof the present wireless transceiver units, which makes it possible to searchan area a lot quicker.

[00012] According to one embodiment, the command message furthercomprises instructions to relay the presence check signal. The method ofrelaying further comprises, based on the command message received at theadditional wireless transceiver unit, broadcasting the presence check signalincluding a second command message, from the additional wirelesstransceiver unit, and listening for presence check acknowledgements fromanother additional wireless transceiver unit, at the additional wirelesstransceiver unit. The method further comprises, upon receipt of a presencecheck acknowledgement from the other additional wireless transceiver unit,transmitting the presence check acknowledgement of the other additionalwireless transceiver unit from the additional wireless transceiver unit to the initiating wireless transceiver unit, using the local network transceiver.

[00013] The relay method makes it possible to extend the reach of thepresence and/or status check and thereby makes it possible to cover amuch larger area with the search.

[00014]A method in a wireless transceiver unit is further provided. Thewireless transceiver comprises a local network transceiver, for verifying thepresence of users running a status check application on their wireless 5 transceiver units. The method comprises a presence check comprisingsetting up a group list specific to the status check application comprising atleast one additional wireless transceiver unit, each wireless transceiver uniton the group list having a group list ID, and transmitting an applicationspecific presence check broadcast, including the group list ID and acommand message, using the local network transceiver. The method furthercomprises listening for a broadcast presence check acknowledgement,using the local network transceiver, from the at least one additional wirelesstransceiver unit, and upon receipt of a presence check acknowledgement,including the group list ID, from the at least one additional wirelesstransceiver unit, updating the group list by marking the at least oneadditional wireless transceiver unit as present.

[00015] According to one embodiment, the method further comprises astatus check. The status check comprises sending a status check messageto at least one present wireless transceiver unit, listening for status checkmessage acknowledgements from the at least one present wirelesstransceiver unit, and upon receipt of a positive status check messageacknowledgement from the at least one present wireless transceiver unit,updating the group list by marking the at least one present wirelesstransceiver unit as ok, and upon receipt of a negative status check messageacknowledgement, or in the absence of a status check messageacknowledgement, from the at least one present wireless transceiver unit,updating the group list by marking the at least one present additionalwireless transceiver unit as not ok. The status check may be an integrated part of the presence check.

[00016]According to one embodiment, the method further comprisesinitiating a search procedure for at least one present wireless transceiverunit marked as not ok. The search procedure comprises listening forsignaling from the at least one present wireless transceiver unit marked asnot ok, determining the signal strength received from the at least one 6 present wireless transceiver unit marked as not ok, and using thedetermined signal strength for determining the location of the at least one present wireless transceiver unit marked as not ok.

[00017] According to one embodiment, the method further comprises usingthe determined signal strength for calculating a search pattern, which maybe provided to another wireless transceiver unit. By providing a calculatedsearch pattern to additional wireless transceivers, the search may be coordinated such that a larger area can be covered much faster.

[00018] According to one embodiment, the method further comprisesinitiating a search procedure for at least one present wireless transceiverunit marked as not ok. The search procedure comprises listening forsignaling from the at least one present wireless transceiver unit marked asnot ok, determining the signal strength received from the at least onepresent wireless transceiver unit marked as not ok, and connecting to atleast one present wireless transceiver unit marked as ok. The methodfurther comprises receiving information regarding the received signalstrength of at least one present wireless transceiver unit marked as not ok,from the at least one present wireless transceiver unit marked as ok, usingthe determined signal strength and the received information for calculating asearch pattern, and transmitting data based on the calculated search pattern to the at least one present wireless transceiver unit marked as ok.

[00019] By constantly receiving information about signal strength from a lost device the lost device can be positioned in an efficient way.

[00020] According to one acknowledgement may comprise location information. embodiment, the presence check

[00021]A method in a wireless transceiver unit for verifying the presence of users running a status check application on their wireless transceiver units is 7 further provided. The wireless transceiver unit being part of an applicationspecific group list on which each wireless transceiver unit has a group listID, the wireless transceiver unit comprising a local network transceiver. Themethod comprises a presence check comprising receiving a broadcastthe broadcast presence check including a command message, and transmitting a presence check, using the local network transceiver,broadcast presence check acknowledgement comprising the group list ID ofthe wireless transceiver unit, on the basis of the command message, using the local network transceiver.

[00022] According to one embodiment, the command message furthercomprises instructions to relay the presence check signal. The methodfurther comprises, based on the received command message, broadcastingthe presence check signal including a second command message, andlistening for presence check acknowledgements from at least one additionalwireless transceiver unit. Upon receipt of a presence checkacknowledgement from the at least one additional wireless transceiver unit,transmitting the presence check acknowledgement of the at least oneadditional wireless transceiver to an initiating wireless transceiver unit, using the local network transceiver.

[00023] According to one embodiment the method further comprises astatus check comprising receiving a status check message, using the localnetwork transceiver, prompting a user of the wireless transceiver unit forpositive or negative status, upon receipt of a positive status input,transmitting a positive status check message acknowledgement, and uponreceipt of a negative status input, or in the absence of a status input,transmitting a negative status check message acknowledgement.

[00024] According to one embodiment, the status check is an integrated part of the presence check. 8

[00025] According to one embodiment the command message furthercomprises instructions to transmit a status check message to at least oneThe method furtherbroadcasting a status check message to at least one additional wireless present wireless transceiver unit. comprisingtransceiver unit, listening for a status check message acknowledgementfrom the at least one additional wireless transceiver unit. Upon receipt of apositive status check message acknowledgement from the at least oneadditional wireless transceiver unit, transmitting a second positive statuscheck message acknowledgement, and upon receipt of a negative statuscheck message acknowledgement, or in the absence of a status checkmessage acknowledgement, transmitting a second negative status check message acknowledgement.

[00026] According to one embodiment, the method further comprisesreceiving a further command message to initiate a search procedure. Thecommand message includes the group list ID of a wireless transceiver unitmarked as not ok. The method further comprises listening for signaling fromthe at least one present wireless transceiver unit marked as not ok,determining the signal strength received from the at least one presentwireless transceiver unit marked as not ok, and transmitting data related to the determined signal strength to the initiating wireless transceiver unit.

[00027] According to one embodiment, the method further comprises usingthe determined signal strength for determining the location of the at least one present wireless transceiver unit marked as not ok.

[00028] According to one embodiment, receiving the further commandmessage further comprises receiving a calculated search pattern, andproviding the calculated search pattern to a user of the wireless transceiver unit.

[00029]According to one embodiment, at least one of the steps oftransmitting a presence check acknowledgement and transmitting a statuscheck message comprises transmitting location information related to the location of the wireless transceiver unit.

[00030] According to one embodiment receiving a broadcasted presencecheck signal comprises receiving an invite message to join a group list andwherein the step of transmitting a presence acknowledgement comprisesthe step of accepting the invite.

[00031] According to one embodiment, the method further comprisesautomatically repeating the step of broadcasting the presence check signal including a command message.

[00032] A method in a transceiver unit, comprising a local networktransceiver, for checking the status of at least one wireless transceiver unit,is further provided. The method comprises a presence check comprisingbroadcasting a presence check signal, using the local network transceiver,listening for a broadcasted presence check acknowledgement from at leastone wireless transceiver unit. Upon receipt of a presence checkacknowledgement from the at least one additional capable wirelesstransceiver unit, creating a group list of present wireless transceiver units,sending a status check message to at least one present wireless transceiverunit, listening for status check message acknowledgements from the at leastone present wireless transceiver unit. Upon receipt of a positive statuscheck message acknowledgement from the at least one present wirelesstransceiver unit, updating the group list by marking the at least one presentwireless transceiver unit as ok, and upon receipt of a negative status checkmessage acknowledgement, or in the absence of a status check message acknowledgement, from the at least one present wireless transceiver unit, updating the group list by marking the at least one present additional wireless transceiver unit as not ok.

[00033] A wireless transceiver unit configured to run a status checkapplication is further provided. The wireless transceiver unit having a grouplist ID and being part of a group list specific to the status check application.The wireless transceiver unit comprising a local network transceiver. Thewireless transceiver unit comprises a local network receiving unit, configuredto receive a broadcast presence check signal including the group list ID anda command message with instructions to perform presence verification, anda local network transmitting unit, configured to a transmit a presence checkacknowledgement comprising the group list ID, on the basis of the command message.

[00034] According to one embodiment of the wireless transceiver unit, thecommand message further comprises instructions to relay the presencecheck signal and wherein:

[00035] a.broadcast, based on the received command message, the presence check the local network transmitting unit is further configured to signal including a second command message. The local network receivingunit is further configured to listen for presence check acknowledgementsfrom at least one additional wireless transceiver unit, and the local networktransmitting unit is further configured to, upon receipt of a presence checkacknowledgement from the at least one additional wireless transceiver unit,transmit the presence check acknowledgement of the at least one additionalwireless transceiver to an initiating wireless transceiver unit, using the local network transceiver.

[00036] According to one embodiment, the local network receiving unit isfurther configured to receive a status check message, using a local networkreceiver for which the wireless transceiver unit further comprises a prompting unit configured to prompt a user of the wireless transceiver unit 11 for positive or negative status and for which the local network transmittingunit is further configured to, upon receipt of a positive status input, transmit apositive status check message acknowledgement. The local networktransmitting unit is further configured to, upon receipt of a negative statusinput, or in the absence of a status input, transmit a negative status check message acknowledgement.

[00037] According to one embodiment, the local network transmitting unit isconfigured to broadcast the status check as integrated part of the presencecheck.

[00038] A computer program product comprising a computer-readable non-transitory storage medium with instructions adapted to carry out the methodof any one of the embodiments herein when executed by a device havingprocessing capability, is further provided.

[00039] Please note that the embodiments above can be combined withinthe scope of the appended claims unless such combinations are clearlycontradictory. 12 Brief description of the drawinqs

[00040] Fig. 1A' and 1A" shows a schematic view of a method forpresence check between users of wireless transceiver units.

[00041] Fig. 1B is a flow chart of a method for presence checkbetween users of wireless transceiver units.

[00042] Fig. 2 is a flow chart of a method for status checkbetween users of wireless transceiver units.

[00043] Fig. 3A”, 3A” and 3A"' shows a schematic view of a method of performing and relaying a presence check procedure between users of wireless transceiver units.

[00044] Fig. 3B is a flow chart of a method for relaying a presencecheck procedure between users of wireless transceiver units.[00045] Fig. 4A', 4A" and 4A"' shows a schematic view of a method for performing a search and rescue operation betweenusers of wireless transceiver units.

[00046]search and Fig. 4B is a flow chart of a method for performing a rescue operation between users of wirelesstransceiver units.

[00047]presence check between users of wireless transceiver units and Fig. 5A' and 5A” shows a schematic view of a method for additional infrastructure.[00048]between users of wireless transceiver units and additional Fig. 5B is a flow chart of a method for presence check infrastructure. 13 Detailed description

[00050]The method, devices and system presented in this disclosureenabling autonomous presence check and thereafter optionally Iocatinggroup members relatively the one(s) searching using mobile phones withcellular and local network capacities, e.g. Wi-Fi.

[00051]A method, system and associated devices are provided for verifyingthe presence of users running a status check application on their wirelesstransceiver units. At least one participating wireless transceiver unit runningthe status check application is an initiating wireless transceiver unit having alocal network transceiver and at least one participating wireless transceiverunit running the status check application is an additional wireless transceiverunit having a local network transceiver. The initiating wireless transceiverunit is configured to initiate a presence check comprising setting up, in theinitiating wireless transceiver unit, a group list of participating wirelesstransceiver units. The group list is specific to the status check applicationand comprises at least one additional wireless transceiver unit. Eachparticipating wireless transceiver unit has a group list ID linking the group listto the specific participating wireless transceiver unit.

[00052] The method is initiated by the initiating wireless transceiver unitbroadcasting an application specific presence check signal, which includes acommand message using the local network transceiver of the initiatingwireless transceiver unit. An additional wireless transceiver unit which is inrange of the transmission receives the broadcast presence check signalincluding the command message, using the local network transceiver of theadditional wireless transceiver unit. Upon receipt of the broadcast presencecheck signal, the additional wireless transceiver unit transmits a broadcastpresence check acknowledgement which comprises the group list ID of theadditional wireless transceiver unit, on the basis of the command message, using the local network transceiver. 14

[00053] ln the meantime, the initiating wireless transceiver unit listens for thebroadcast presence check acknowledgement, using the local networktransceiver. Upon receipt of a presence check acknowledgement, includingthe group list ID from the additional wireless transceiver unit, the initiatingwireless transceiver unit updates the group list by marking the additional wireless transceiver unit as present.

[00054] ln a first embodiment, the above method is preceded by a procedurein which the group linked by means of the application specific group list isdefined and the users of participating wireless transceiver units have optedin. However, in one embodiment, the step of setting up the group andcreating the closed group list can be overridden in cases of emergency andby those authorized to do so (typically emergency response agencies),which means that such super users can create groups in which all wireless transceiver units present on a particular geographical area will participate.

[00055] ln one exemplifying embodiment of the procedure of creating thegroup defined by the application specific group list, a unique group identity iscreated, which is a part of the signaling message used by any groupmember when a check for other group member's local presence is activated.

[00056] ln one exemplifying embodiment, the presence check configured todisclose which group members are locally present is performed by theinitiating device using a standard local network radio technology broadcastmessage (e.g. using the Wi-Fi standard), composed in such way it includesthe group identity, the command message (e.g. incorporating instructionswith regards to how to respond to the presence check message), andoptionally also parameters representing the current location (e.g. GNSS(e.g. GPS) coordinates). lt may also include other information about thegroup, such as information concerning the location of other members and/or information about other members.

[00057] The presence check procedure described above may be succeededby, or have integrated in, a procedure for status check. According to oneembodiment, the procedure for status check comprises sending a statuscheck message from the initiating wireless transceiver unit, using the localnetwork transceiver, to at least one present additional wireless transceiverunit. The additional wireless transceiver then, e.g. on the basis of anincluded command message, prompts the user of the additional wirelesstransceiver unit for positive or negative status (e.g. if the user is ok or inneed of any form of assistance). Upon receipt of a positive status input inthe at least one present additional wireless transceiver unit, the additionalwireless transceiver unit transmits a positive status check messageacknowledgement to the initiating device. ln the contrary, upon receipt of anegative status input, or in the absence of a status input, the additionalwireless transceiver unit transmits a negative status check messageacknowledgement. ln the meantime, the initiating wireless transceiver unitlistens for status check message acknowledgements from the at least onepresent additional wireless transceiver unit, and upon receipt of a positivestatus check message acknowledgement, at the initiating wirelesstransceiver unit, from the at least one present additional wireless transceiverunit, the group list is updated by the marking of the at least one presentadditional wireless transceiver unit as ok, and upon receipt of a negativestatus check message acknowledgement, or in the absence of a statuscheck message acknowledgement, from the at least one present additionalwireless transceiver unit, the group list in the initiating wireless transceiverunit is updated by the marking of the at least one present additional wireless transceiver unit as not ok.

[00058] ln one exemplifying embodiment, if the user has not transmitted apositive status check message or if the user has transmitted a negativestatus check message acknowledgement, the application automaticallyswitches to a “rescue me” mode and is marked in the group list by theinitiating device as a “lost device”. 16

[00059] The presence and/or status check procedures described above aretypically executed in scenarios such as emergency situations where somemembers in the group tries to locate other members. Example applicationsare avalanche rescue applications, and locating children or constructionworkers not answering when called upon. Obviously, the same principlesand procedures as described among users can be applied also for machine-to-machine or man-to-machine application where one or several of the users and devices are replaced by machines that are mobile or fixed installations.

[00060] Today, a standard mobile phone, which is a wireless transceiverunit, is equipped with both multiple means and technologies for cellular andlocal wireless communication and internet access. They are also equippedwith multiple sensors and high resolution touch screens. The features of amobile phone thus make it possible to implement applications used toidentify, locate and track users of other wireless transceiver units. Whencombined with integrity protecting hard and/or software, a mobile phone canbe used to keep track of people and/or equipment in a way such thatapplications which are today implemented in dedicated tools and equipment can be replaced.

[00061]Broadcast is to be understood as public radio communicationtransmitted by a local network transceiver and receivable by any local network transceiver of same or similar type.

[00062] Local network transceiver is to be understood as a radio transceiverof the wireless transceiver unit capable of creating a local network. ln theexemplifying embodiments described with reference to the accompanyingfigures, Wi-Fi, wireless local area network technology based on the IEEE802.11 standards is used. However, it is conceivable that other radio standards, such as Wi-Fi Direct, may be used for the local network 17 transceiver as long as they are capable of transmitting and receiving open broadcast communication.

[00063] Command message is to be understood as any message whichcould contain information which could be interpreted as instructions. Acommand message may be part of the name of a network, such as SSID, or device name.

[00064] Below, specific embodiments of the present invention are described.lt will be appreciated that the drawings are for illustration only and are not inany way restricting the scope of the invention. Thus, any references todirections, such as “up” or “down”, are only referring to the directions shownin the figures. lt should be noted that the features having the same referencenumerals have the same function, a feature in one embodiment could thusbe exchanged for a feature from another embodiment having the samereference numeral unless clearly contradictory. The descriptions of thefeatures having the same reference numerals should thus be seen ascomplementing each other in describing the fundamental idea of the featureand thereby showing the features versatility.

[00065] FIG. 1A' and 1A" shows a schematic view of a method for presencecheck between users of wireless transceiver devices running a status checkapplication. According to the embodiment of fig. 1A' - 1B, a group is createdby a user of an initiating device A which runs a status check application. Theinitial group list creation step is shown as step SA of fig. 1B. The user of theinitiating device A becomes the owner and administrator of the status checkapplication specific group which initially is empty. Even if the initiating deviceA is the owner and administrator of the group, the group can later betransferred to another member and/or multiple users may be assigned asadministrators for the group. 18

[00066] ln one exemplifying embodiment, a user with administratorauthorities can invite members to the group, remove members and changegroup common settings in the status check application. The owner of thegroup can delete the entire group. lt is further more conceivable that a usercan be owner, but not administrator. This means that the owner can removethe group, but cannot change the group or the group settings. lt is furthermore conceivable that a user can have an account type that is a pureadministrator account, meaning this user does not have a device that can be used for presence and/or status verification and/or location determination.

[00067] As a next step in a procedure to set up an group list specific to thestatus check application, the owner and administrator starts to invite otherusers of wireless transceiver units, B1, B2 and C1 to the group. lnvites maybe sent as e.g. text or e-mail messages and may include instructions for, ora link for, downloading the status check application. When being invited, theusers B1, B2 and C1 can be requested to accept the invitation to be addedto the group list specific to the status check application. Each member, i.e.each wireless transceiver unit, of the group list is assigned a specific grouplist ID, which can be used to identify each user.

[00068] Members in the group of users B1, B2 and C1, in the embodimentshown in fig. 1A' and fig. 1A", become members with the default user type“member”, which means that they do not receive administrator rights.However, this may be changed by the initiating device being group owner and/or administrator.

[00069]A member in the group of users B1, B2 and C1 are either activatedor deactivated. Activated means that the user will be included in proceduresto verify presence or determine location, while deactivated means it will notbe included. ln the embodiment shown in figs. 1A' - fig. 1B, the groupadministrators sets the policies for whether or not the user can set status them self in the status check application. 19

[00070] ln the group creation and set-up of the embodiment of fig. 1A' - fig.1B, a number of fundamental signaling messages and policies are definedand provisioned in all members devices and in the status check application.The main principle behind the presence and status check procedure whichmay be performed using the status check application is using a wirelessnetwork broadcast signal, e.g. the Wi-Fi SSID message. An applicationand/or group unique SSID is generated. Also, policies for what to do whenthe SSID is received by the application of an active user are set. Example ofpolicies are when and for what reasons the user of the wireless transceiverunity should be prompted and requested to confirm, how long the statuscheck application should wait for such confirmation, and what happenswhen confirmation is received or not received. Other example of policies is ifand how confirmation can be accepted also after the time has passed and towhat extent the application and members of the status check applicationgroup list can access position information provided by the wireless transceiver unit.

[00071]Once the status check application group is created, and the firstusers of wireless transceiver units are added, the status check application is ready to be used.

[00072] ln the embodiment shown in figs. 1A' - 1B, the method for verifyingthe presence of the users running the status check application on theirwireless transceiver units 1A, 1B1, 1B2 is shown. The initiating wirelesstransceiver unit 1A in the embodiment shown in figs. 1A' - 1B is user A, i.e.user A would like to verify presence of additional wireless transceiver units.However, it may be any of the users A, B1, B2 or C1, which are the initiatingdevice. Each of the wireless transceiver unit comprising a local network transceiver.

[00073] The initiating device A, broadcasts an application specific presencecheck signal which includes a command message, i.e. instructions abouthow the receiving wireless transceiver unit shall act. The initiating wireless transceiver uses the local network transceiver, being method step SB of fig.1B. The broadcast presence check signal is received by the local networktransceivers of the additional wireless transceiver units B1 and B2,schematically shown in fig. 1A", which are within the range of the wirelessbroadcast, this being shown as method step SC in fig. 1B.

[00074] The additional wireless transceiver units B1 and B2 responds to thepresence check signal on the basis of the command message whichinstructs the additional wireless transceivers to broadcast a presence checkacknowledgement which includes their individual group list ID, using theirrespective local network transceiver, this being shown as method step SD infig. 1B. ln the embodiment of figs. 1A" - 1B, the acknowledgement is sentusing broadcast signal (SSID).

[00075] ln the meantime, after having transmitted the application specificpresence check signal for e.g. a defined time, the initiating device A starts tolisten for broadcast presence check acknowledgements using the localnetwork transceiver, which is shown as method step SE in fig. 1B.

[00076] When acknowledgement, including the group list ID from the additional wireless the initiating user A receives a presence checktransceiver unit, the initiating device updates the group list specific to thestatus check application, by marking the additional wireless transceiver unitas present, which is shown as method step SF in fig. 1B. The initiatingdevice may also mark additional wireless transceiver units as not present, e.g. if no acknowledgement is received after a defined time.

[00077]ln the embodiment of figs. 1A' -acknowledgement provided by the additional wireless transceiver units 1B1, B the presence check 1B2 may comprise location information, which for example may be GNSS (e.g. GPS) information.

[00078] As explained above, the invitation to join a group may be performed by means of a text message or an email. However, it is equally conceivable 21 that the invite message and/or application download and/or installationinformation is integrated in the presence check signal, in which case thestep of transmitting a presence acknowledgement may comprises the stepof accepting the invite.

[00079] The method explained above may be used to verify the presence ofgroup members within a limited range. The presence check method may bemanually triggered or performed automatically by the wireless transceiverunits, e.g. on the basis of a defined time interval between checks. Anexample of cases in which manually triggered presence checks may becalled for is in cases of a rescue operation, such as e.g. after an avalanche,earthquakes or fire. Examples of cases in which continuous polling may becalled for could be to keep track of groups of users that are supposed tostay within a defined distance, and/or cases in which it is crucial that a groupleader continuously is aware of the group member's location.

[00080] The presence detection method in any of the embodiments hereinmay be based on Wi-Fi signaling in which the SSID broadcast signal and the32 bytes of characters are used for signaling messages and instructionparameters. Reponses to the broadcasted messages may be signaled eitherby establishing a connection (e.g. attach to the initiating parties network, orby establishing a new ad-hoc network) or by using broadcast means for this as well.

[00081] Fig. 2 is a flow chart of a method of performing the status checkusing the status check application previously described with reference tofigs. 1A' - 1B. The method comprises sending, SG, a status checkcomprising sending a status check message from the initiating wirelesstransceiver unit (A of figs. 1A' and fig. 1A"), using the local networktransceiver, as an SSID broadcast signal to at least one additional wirelesstransceiver unit (B1, B2 of figs. 1A' and fig. 1A") marked as present in thegroup list administered by the initiating device. The method furthercomprises prompting, SH, a user of the at least one present additional 22 wireless transceiver unit for positive or negative status. The step ofprompting may comprise displaying a prompt on the display of the additionalusers wireless transceiver unit and receiving input from the user. The promptmay e.g. be the question “are you ok” and comprise two alternativeresponse buttons on a touch panel of the wireless transceiver unit, “ok” and“not ok”.

[00082] The method further comprises upon receipt of a positive statusinput, e.g. an “ok” input, in the at least one present additional wirelesstransceiver unit, transmitting, S|2, a positive status check messageacknowledgement, and upon receipt of a negative status input, e.g. a “notok” input, in the at least one present additional wireless transceiver, or in theabsence of a status input, transmitting, SI1, a negative status checkmessage acknowledgement. The absens of a “ok” responce within a definedtime period may also be interpreted as a “Not ok” responce", meaning thatan alternative is to have only one alternative answer button beeing ok and ifthe user have not activly confirmed using that button user is assumed as“Not ok”.

[00083] ln the meantime, the initiating wireless transceiver switches formtransmitting the status check signal to listening for status check messageacknowledgements. When the initiating wireless transceiver unit receives apositive status check message acknowledgement from an additionalwireless transceiver unit, the initiating wireless transceiver updates thegroup list by marking the at least one present additional wireless transceiverunit as ok, and when the initiating wireless transceiver unit receives anegative status check message acknowledgement, or in the absence of astatus check message acknowledgement, the initiating wireless transceiverunit updates the group list in the initiating wireless transceiver unit bymarking the at least one present additional wireless transceiver unit as “notok”. lt is also conceivable that the wireless transceiver unit transmits a “notok” message on the basis of the wireless transceiver unit not receiving confirmation from the user of the wireless transceiver unit. i.e. the 23 application may have a feature that makes the wireless transceiver unitrespond with a negative status acknowiedgement in the case that it takestoo long for the user of the wireless transceiver unit to respond if promptedwith the “are you ok?" question.

[00084] ln accordance with one embodiment, the status check method is anintegrated part of the presence check described earliera and the user maybe asked to provide status information befor the wireless tranceiver unit acknowledgs a presens check signal.

[00085]Just as in the case with the presence check, the status check maybe manually or automatically triggered based e.g. on time of location information.

[00086] ln one embodiment, an additional wireless transceiver may beconfigured to constantly broadcast a signal containing e.g. “l'm here” + IDand optionally location information. lf the additional wireless transceiverknows that it has lost the group, the additional wireless transceiver mayswitch to broadcasting “l'm lost" + ID and optionally location information, e.g.the switch may occur if no other member of the group list is being detected,too few other member of the group list are being detected, or one or severalout of a “must-see” members are not present. The switch may further occurif the wireless transceiver unit senses that it is in a distressed situation, e.g. using accelerometer input.

[00087]Fig. 3A' - fig. 4 shows an implementation of a presence checkapplication being similar to the implementation disclosed with reference tofigs. 1A' - 2. However, in the embodiment disclosed in figs. 1A' - 2, thebasic idea to the check if and how many of the members in a group list arelocated in the direct vicinity of the initiating wireless transceiver unit (A). Forthis basic purpose, the additional wireless transceiver units 1B1, 1B2 automatically respond by acknowledging the presence check but do not 24 repeat or relay the message. This means that the presence check range islimited by the range of the broadcast signal from the local networktransceiver of the initiating wireless transceiver 1A. ln this regard, thepresence check performed in the embodiment described in fig. 1A' - fig. 2 is the same with regards to the part of the method shown in fig. 3A'.

[00088] However, in an alternative embodiment the range of presence checksignal may be extended using a repeater principle. As shown in fig. 3A",when an additional wireless transceiver 1B2 receives a broadcast from aninitiating wireless transceiver unit 1A, the command message of such abroadcast includes an instruction to repeat the signal. As is shown in fig. 3A”the wireless transceiver unit 1B2 repeats the signal received from theinitiating wireless transceiver 1A such that the repeated broadcast signal can reach further, and in the embodiment shown in fig. 3A reach the wireless transceiver 1C1.

[00089] The repeating devices B1 and B2 may in this case, based on thecommand message received from the initiating wireless transceiver and/oron application settings, add additional information to the transmitted signal,which may include information such as which device have repeated thesignal and possibly information about the repeating device, e.g. the locationof said device.

[00090]When the additional wireless transceiver units 1B1 and 1B2receives the presence check signal, the devices will, after the signal isreceived, also go to transmitting mode and 1B1 will transmit a presencecheck signal + a second command and/or information signal which mayinclude parameters added by 1B1, while 1B2 will transmit a presence checksignal + a second command and/or information signal which may include parameters added by 1B2.

[00091]A device receiving a repeated signal may in the response include information about from where the signal was repeated.

[00092]Fig. 3B shows the method performed by an additional wirelesstransceiver unit, also described by the schematic figures 3A' - 3A"', as aflow chart. The method described includes the steps of, based on thecommand message received, SA', at the additional wireless transceiver unit,broadcasting, SB', the presence check signal including a second commandmessage, from the additional wireless transceiver unit. After havingtransmitted the presence check signal including the second commandmessage for e.g. a defined time, the additional wireless transceiver units(1B1, 1B2 of figs. 3A' - 3A"') switches to listening SC', for presence checkacknowledgements from other additional wireless transceiver unit. Uponreceipt of a presence check acknowledgement from another additionalwireless transceiver unit (1C1 of figs. 3A' - 3A"'), the additional wirelesstransceiver unit 1B2 transmits the presence check acknowledgement of theother additional wireless transceiver unit 1C1 from the additional wirelesstransceiver unit 1B2 to the initiating wireless transceiver unit 1A1, using the local network transceiver.

[00093] The repeating of the broadcast of the presence check signal may inthe embodiments described above be performed automatically or on the basis of a manual input from the user of the additional wireless transceiver.

[00094] ln an alternative embodiment, the presence check signal may beused as a continuous “heartbeat” function within the group of users beingpart of the group list. The continuous “heartbeat” function can beimplemented by all wireless transceiver units in a group frequentlytransmitting a presence check signal to verify the presence of other wirelesstransceiver units in the group, or it may be implemented as one, or more,wireless transceiver units being the initiating wireless transceiver unit ormaster and continuously or according to a schedule or scheduling principle transmitting the presence check signal. Depending on what principle is 26 used, the procedure may also include an acknowledge signal transmitted bywireless transceiver units that receive the heart beat signal.

[00095] lf a wireless transceiver unit in the group loses the contact with theother members, detected as a non-received heart beat or a non-acknowledged heartbeat, the wireless transceiver unit turns on the “l'm lost”signal. This signal can also be manually triggered by the lost user of the wireless transceiver unit.

[00096] Turning on the “l'm lost” signal means first of all that all othermembers of the group list will immediately detect and report the user withthe wireless transceiver unit transmitting the “l'm lost” signal. Also,depending on group policy setting, users not part of the group may alsodetect the “l'm lost” signal and act on that, e.g. by reporting back to a serverincluding the location of where the user is detected.

[00097] While the “l'm lost” signal may be triggered by a lack of heart beat orlack of other wireless transceiver units on the group list responding on apresence check signal, the “l'm lost” signal is however also considered as apresence check signal.

[00098] When the additional wireless transceiver units of the group listincluding the lost wireless transceiver unit receives the “l am lost” signal,such group list members may also receive information about via whom andwhen it was reported. Such information may be received from a server incommunication with the lost wireless transceiver unit, and in the alternative,users which are not members of the group detecting the “l am lost” signal,may add a parameter to their broadcast heart-beat signal including relevantinformation (such as group list ID, location, time etc.) of the received “l amlost” signal. The information regarding the lost device may also be picked upby a third party wireless transceiver unit, which is a considerable advantagewith using the open broadcast layer. The third party wireless transceiver unit may in turn repeat the procedure. Hence, all users may pick up and 27 transfers further the information, which means that once a user who haspicked up this information passes a group member of the lost user, theinformation is received and may be acted on. For integrity purposes, theidentity of the lost user may be unknown to the repeating third party, whomay only get the information that it is important to repeat the message, without knowing why.

[00099]Fig. 4A' - 4B is a schematic illustration of an embodiment of asearch and rescue procedure using the wireless transceiver units runningthe status check application previously described. The search and rescueprocedure is similar to the scenarios described in figs. 1A'- 1A" and 3A' -3A"', with the difference that the presence and status check is followed by asearch and rescue procedure if the presence check reveals that one or moreuser, who should have been present, is missing and/or in case that the status check reveals that the status of one or more user is not ok.

[000100] the example of a rescue operation following an avalanche will be used, ln the embodiment disclosed with reference to figs. 4A' - 4B, however, the method may just as well be used in any other situation inwhich a search for a missing wireless transceiver unit needs to beperformed, e.g. the search of a lost child in an amusement park, the searchof a lost construction worker following an accident or in the search oftrapped residents in a burning building or when rescuing people in a cave inwhich there is no cell phone coverage.

[000101]present users A, B1, B2, C1, and C2, each having a wireless transceiver ln fig. 4A', the application specific group list comprises five unit 1A, 1B1, 1B2, 1C1, 1C2 each having a local network transceiver in theform of a Wi-Fi transceiver capable of broadcasting an SSID. The fivepresent users are one initiating user A, two additional present users with“ok” status B1, B2 and two lost users C1, C2 with unknown or “not ok”status. To locate users in the application specific group list, the initiating user A initiates search mode on the initiating users wireless transceiver unit. 28 Search mode can be initiated manually, or as an action triggered by theapplication based on other decision criteria or configurations.

[000102] transmitting a search mode signaling, as a broadcast SSID using the local The search procedure is initiated by the initiating user A network transceiver of the wireless transceiver unit 1A, instructing theadditional users in the group list to switch to search mode (fig. 4A'). Whenthe wireless transceiver units 1B1 and 1B2 receives the instructions, thewireless transceiver units 1B1 and 1B2 switches to search mode andacknowledges the receipt (fig. 4A") of the instructions to the initiating wireless transceiver unit 1A.

[000103]transceiver units 1B1, 1B2, the wireless transceiver units marked as ok, 1A, After the acknowledgement from the additional wireless 1B1, 1B2 all starts to listen for signaling from at least one present additional wireless transceiver unit marked as “not ok”.

[000104]the wireless transceiver units to presence check mode for the purpose of When in search mode, the application may intermittently switch incorporating further additional wireless transceiver units which may have arrived at the location at a later stage.

[000105]wireless transceiver units 1C1, 1C2 have been buried by an avalanche. As ln the example of figs. 4A' - 4A"', two users C1, C2 and their both the signals transmitted from the wireless transceiver units 1A, 1B1,1B2 of the searching members of the group list and the lost wirelesstransceiver units 1C1, 1C2, will be transmittals of an SSID using thebroadcast of the local network transceiver, Wi-Fi transceiver, the wirelesstransceiver units will transmit at full effect, making the transmitted signals penetrating several meters of snow.

[000106]receives the broadcasted signals from the lost wireless transceiver units, the When the searching wireless transceiver units 1A, 1B1, 1B2 29 searching units will determine the signal strength received from the at leastone present wireless transceiver unit marked as not ok. The signal strengthmay be determined as for example RSSI (Received Signal Strengthlndication) and/or as RCPI (Received Channel Power lndicator). As thesearching user A, B1, B2 moves, the changes in signal strength may beused to determine the distance to and the direction of the location of themissing wireless transceiver units 1C1, 1C2.

[000107] unit may connect and create a session with a lost wireless transceiver unit ln an alternative embodiment, a searching wireless transceiver when the signal is sufficiently strong. Alternatively the signaling from a lostwireless transceiver unit may be relayed by the additional wirelesstransceiver unit 1B1, 1B2 being closest to the lost device, but may howeveralso by directed and understood directly by the initiating wireless transceiverunit 1A. One disadvantage with creating a private signaling session betweenan additional wireless transceiver unit 1B2 and a lost wireless transceiverunit 1C2 is that the initiating device 1A will then not understand that privatesignaling, which will make a search and rescue operation dependant on theconnection between the units 1B2, 1C2 having the private session. ln theembodiment in which all responses are transmitted as open broadcasts, allparticipating wireless transceiver units may participate in the searching andlocating of a wireless transceiver unit, which enables the creation of efficient search patterns.

[000108] ln the embodiment shown in figs. 4A' - 4A"', the determinedsignal strength in all of the participating searching devices 1A, 1B1, 1B2 areused to calculate a search pattern, i.e. a map and/or instructions for how thesearching users should move to search as large of an area as possibleand/or to arrive at the lost user as quickly as possible. ln the embodimentshown in figs. 4A' - 4A"', the determined signal strength at each of theadditional wireless transceiver units 1B1, 1B2 are relayed to the initiatingwireless transceiver unit 1A which comprises a calculating unit configured to calculate the search pattern and provide the calculated search pattern to the additional wireless transceivers 1B1, 1B2. This way. the users of thesearching wireless transceiver units gets instructions on how to movethroughout the search sequence, and the algorithm of the calculating unitmay calculate not only estimated location of lost devices, but also an optimal route based on previous measurement and estimates.

[000109]algorithm may be performed and/or supervised by a remote server, which ln an alternative embodiment, the calculation of the search may be a server which is part of a search and rescue organization. [oooi 10] various positioning means such as GPS or other GNSS. E.g. the lost device The determining of the signal strength may be combined with may include the last available positioning data in the transmitted SSID,which may significantly shorten the time it takes to locate the position lostwireless transceiver unit. lt is also conceivable that the initiating wirelesstransceiver uses positing data of the additional searching wireless transceiver units for the purpose of calculating the search pattern.

[000111]strength, the uncertainty and how the uncertainty decreases can also be When performing the measurements to determine signal measured, hence it is possible to indicate to the user when further searchingwill not improve the accuracy and the user should use other means to locatethe exact position. How big the uncertainty is and how it decreases dependson multiple aspects such as wireless technology used, device antenna characteristics, environment, weather etc..

[000112]features apart from the actual search related functionally, such as general A search and rescue application may include several other instructions on how to proceed, numbers to call to PSAP (Public SafetyAnswering Point) or local security organizations, check-lists what to do afterrescue, integration with various information systems to retrieve maps,weather information as well as reporting back data to be used to produce information and tune models. 31

[000113] To further improve the reach and hence performance of thesearch procedure, the embodiment of figs. 4A' - 4A"' may be combined withthe re|ay embodiment of figs. 3A' - 3A"', such as an invitation to join thesearching group list and/or the search procedure may be relayed by allparticipating wireless transceiver units, notably the additional wirelesstransceiver units 1B1, 1B2. How and by whom the signals are relayeddepends on policy settings set by the application and/or the users. Anotherexample of a setting is that any one receiving the invite may be set to re|aythe signal, but receivers who are not already members of the group list may not be allowed or able to decode the message. [oooi 14] additional searchers may be used, i.e. extending the search group. As an lt is furthermore conceivable that additional means for engaging example, additional search invites may be sent to wireless transceiver unitsin the area, coordinated by a server, by means of the telephony network,e.g. by means of a text message service. Wireless transceiver units beingadded to the search group can either be added as a standalone searcher,meaning it is not included in the cooperative search but performs standalonesearch, or added to the cooperative search group. ln the latter case, the newdevice to be added receives information from the received presence check signal.

[000115]and rescue operation described above using signaling in accordance with Fig. 4B is a flow chart of the method of performing the search what has been described in relation to figs. 4A' - 4A"', in which the stepsSD” and SE” are dotted as an indication of these steps being optional.

[000116]described above and performed between users of an application specific ln addition to the presence, status and search methods group list, there can be super groups created by super users, e.g. publicsafety functions or corporate functions. These super users can be used suchthat all created groups are integrated into the super group if needed, e.g. in 32 emergency situations or when blue light organizations are involved in a search and rescue operation. [oooi 17] involving a super user, which in this embodiment is a super user with access Figs. 5A' and 5A" shows an embodiment of the procedure to fixed infrastructure in the form of a Wi-Fi access point 1X. The super usermay be the initiating device or may become involved as a result of aninitiating wireless transceiver unit 1A initiating a presence check and/orstatus check and/or search and rescue operation. The methods involving asuper user may function in the same way as the methods which do notinvolve a super user, i.e. any of the procedures or methods described inhere may have a super user as initiating device or as a device assisting inthe search procedure. [oooi 18] which the super user being a user connected to a Wi-Fi access point Fig. 5B shows a flow chart of a method involving a super user, in broadcasts a Wi-Fi SSID presence check signal SA”', using the localnetwork Wi-Fi transceiver. After a period of broadcasts, the super userswitches to listening SD”' for a broadcasted presence checkacknowledgement from at least one wireless transceiver unit. A wirelesstransceiver unit running the application and thus understanding the SSIDsignal transmitted by the super user, receives the broadcast presence checksignal SB”' and responds to the presence check signal by transmitting abroadcast presence check acknowledgement SC”' comprising the group list ID using the local network transceiver. [oooi 19] wireless transceiver unit, the super user updates the group list by marking Upon receipt of a presence check acknowledgement from the that wireless transceiver unit as present. The signalling for the status checksand search and rescue procedures are basically the same as describedabove for groups not including a super user. However, one significant difference is that a group having a super user may have the capabilities of 33 inviting further participants and using all available infrastructure, such as WiFi acccess points and to some extent mobile phone base stations.

[000120] Please note that the embodiments above can be combinedwithin the scope of the appended claims unless such combinations are clearly contradictory.

Claims (29)

1 _ 34 Claims

1. A method for verifying the presence of users running a status checkapplication on their wireless transceiver units, the wireless transceiverunits (1A,1B1,1B2) comprising an initiating wireless transceiver unit(1A) having a local network transceiver and an additional wirelesstransceiver unit (1 B) having a local network transceiver, the methodcomprises a presence check comprising: a. setting up (SA), in the initiating wireless transceiver unit, a grouplist of wireless transceiver units specific to the status checkapplication, comprising at least one additional wirelesstransceiver unit, each wireless transceiver unit having a grouplist ID, b. broadcasting (SB) an application specific presence check signalincluding a command message, from the initiating wirelesstransceiver unit, using the local network transceiver, c. receiving the broadcast (SC) presence check signal includingthe command message, at the additional wireless transceiverunit, using the local network transceiver, d. transmitting (SD) a broadcast presence checkacknowledgement comprising the group list ID, on the basis ofthe command message, from the additional wireless transceiverunit, using the local network transceiver, e. listening (SE) for a broadcast presence checkacknowledgement, in the initiating wireless transceiver unitusing the local network transceiver, and f. upon receipt, at the initiating wireless transceiver unit, of apresence check acknowledgement, including the group list IDfrom the additional wireless transceiver unit, updating (SF) thegroup list by marking the additional wireless transceiver unit aspresent.

2. The method according to claim 1, further comprising a status checkcomprising: a. sending (SG) a status check message from the initiating wireless transceiver unit, using the local network transceiver, to at least one present additional wireless transceiver unit, _ prompting (SH) a user of the at least one present additional wireless transceiver unit for positive or negative status, _ upon receipt of a positive status input in the at least one present additional wireless transceiver unit, transmitting (Sl2) a positivestatus check message acknowledgement, _ upon receipt of a negative status input in the at least one present additional wireless transceiver, or in the absence of astatus input, transmitting (Sl1) a negative status check message acknowledgement, _ listening for status check message acknowledgements from the at least one present additional wireless transceiver unit, at theinitiating wireless transceiver unit, upon receipt of a positive status check messageacknowledgement, at the initiating wireless transceiver unit,from the at least one present additional wireless transceiverunit, updating (SJ2) the group list by marking the at least onepresent additional wireless transceiver unit as ok, and _ upon receipt of a negative status check message acknowledgement, or in the absence of a status check messageacknowledgement, from the at least one present additionalwireless transceiver unit, updating (SJ1) the group list in theinitiating wireless transceiver unit by marking the at least onepresent additional wireless transceiver unit as not ok.

3. The method according to any one of claims 1 and 2, further comprisinginitiating a search procedure for at least one present additional 36 wireless transceiver unit marked as not ok, the search procedurecomprising: a. listening (SA"), at the initiating wireless transceiver unit, forsignaling from the at least one present additional wirelesstransceiver unit marked as not ok, b. determining (SB"), at the initiating wireless transceiver unit, thesignal strength received from the at least one present wirelesstransceiver unit marked as not ok, and c. using (SC") the determined signal strength for determining thelocation of the at least one present wireless transceiver unitmarked as not ok, at the initiating wireless transceiver unit.

4. The method according to any one of claims 1 - 3, wherein thecommand message further comprises instructions to relay thepresence check signal, the method further comprising: a. based on the command message received at the additionalwireless transceiver unit, broadcasting (SB') the presence checksignal including a second command message, from theadditional wireless transceiver unit, and b. listening for presence check acknowledgements (SC') fromanother additional wireless transceiver unit, at the additionalwireless transceiver unit, and c. upon receipt of a presence check acknowledgement from theother additional wireless transceiver unit, transmitting (SD') thepresence check acknowledgement of the other additionalwireless transceiver unit from the additional wireless transceiverunit to the initiating wireless transceiver unit, using the local network transceiver.

5. A method in a wireless transceiver unit comprising a local network transceiver, for verifying the presence of users running a status check 37 application on their wireless transceiver units, the method comprises a presence check comprising: 8. setting up a group list specific to the status check applicationcomprising at least one additional wireless transceiver unit,each wireless transceiver unit on the group list having a grouplist ID, transmitting an application specific presence check broadcast,including the group list ID and a command message, using thelocal network transceiver, listening for a broadcast presence check acknowledgement,using the local network transceiver, from the at least one additional wireless transceiver unit, and _ upon receipt of a presence check acknowledgement, including the group list ID, from the at least one additional wirelesstransceiver unit, updating the group list by marking the at least one additional wireless transceiver unit as present.

6. The method according to claim 5, further comprising a status check comprising: 8. sending a status check message to at least one presentwireless transceiver unit, listening for status check message acknowledgements from theat least one present wireless transceiver unit, upon receipt of a positive status check messageacknowledgement from the at least one present wirelesstransceiver unit, updating the group list by marking the at least one present wireless transceiver unit as ok, and _ upon receipt of a negative status check message acknowledgement, or in the absence of a status check messageacknowledgement, from the at least one present wireless 38 transceiver unit, updating the group list by marking the at least one present additional wireless transceiver unit as not ok.

7. The method according to claim 6, wherein the status check is an integrated part of the presence check.

8. The method according to any one of claims 6 and 7, further comprisinginitiating a search procedure for at least one present wirelesstransceiver unit marked as not ok, the search procedure comprising: a. listening for signaling from the at least one present wirelesstransceiver unit marked as not ok, b. determining the signal strength received from the at least onepresent wireless transceiver unit marked as not ok, and c. using the determined signal strength for determining the locationof the at least one present wireless transceiver unit marked as not ok.

9. The method according to claim 8, further comprising using thedetermined signal strength for calculating a search pattern.

10.The method according to claim 9, further comprising providing thecalculated search pattern to another wireless transceiver unit.

11.The method according to any one of claims 6 - 8 further comprisinginitiating a search procedure for at least one present wireless transceiver unit marked as not ok, the search procedure comprising: a. listening for signaling from the at least one present wirelesstransceiver unit marked as not ok,b. determining the signal strength received from the at least one present wireless transceiver unit marked as not ok, 39 connecting to at least one present wireless transceiver unit marked as ok, _ receiving information regarding the received signal strength of at least one present wireless transceiver unit marked as not ok,from the at least one present wireless transceiver unit markedas ok, using the determined signal strength and the receivedinformation for calculating a search pattern, and transmitting data based on the calculated search pattern to the at least one present wireless transceiver unit marked as ok.

12.The method according to any one of claims 5 - 11, wherein the presence check acknowledgement comprises location information.

13.A method in a wireless transceiver unit, for verifying the presence of users running a status check application on their wireless transceiver units, the wireless transceiver unit being part of an application specific group list on which each wireless transceiver unit has a group list ID, the wireless transceiver unit comprising a local network transceiver, the method comprises a presence check comprising: 8. receiving a broadcast presence check, using the local networktransceiver, the broadcast presence check including acommand message, and transmitting a broadcast presence check acknowledgementcomprising the group list ID of the wireless transceiver unit, onthe basis of the command message, using the local network transceiver.

14.The method according to claim 13, wherein the command message further comprises instructions to relay the presence check signal, the method further comprising a. based on the received command message, broadcasting thepresence check signal including a second command message,and b. listening for presence check acknowledgements from at leastone additional wireless transceiver unit, and c. upon receipt of a presence check acknowledgement from the atleast one additional wireless transceiver unit, transmitting thepresence check acknowledgement of the at least one additionalwireless transceiver to an initiating wireless transceiver unit, using the local network transceiver.

15.The method according to any one of claims 13 and 14, furthercomprising a status check comprising: a. receiving a status check message, using the local networktransceiver, b. prompting a user of the wireless transceiver unit for positive ornegative status, c. upon receipt of a positive status input, transmitting a positivestatus check message acknowledgement, and d. upon receipt of a negative status input, or in the absence of astatus input, transmitting a negative status check messageacknowledgement.

16.The method according to claim 15, wherein the status check is anintegrated part of the presence check.

17.The method according to any one of claims 14 - 16, wherein thecommand message further comprises instructions to transmit a statuscheck message to at least one present wireless transceiver unit, themethod further comprising:a. broadcasting a status check message to at least one additional wireless transceiver unit, 41 listening for a status check message acknowledgement from theat least one additional wireless transceiver unit, upon receipt of a positive status check messageacknowledgement from the at least one additional wirelesstransceiver unit, transmitting a second positive status checkmessage acknowledgement, and _ upon receipt of a negative status check message acknowledgement, or in the absence of a status check messageacknowledgement, transmitting a second negative status check message acknowledgement.

18.The method according to any one of c|aims 14 - 17, further comprising: 8. receiving a further command message to initiate a searchprocedure, the command message including the group list ID ofa wireless transceiver unit marked as not ok, listening for signaling from the at least one present wirelesstransceiver unit marked as not ok, determining the signal strength received from the at least onepresent wireless transceiver unit marked as not ok, andtransmitting data related to the determined signal strength to the initiating wireless transceiver unit.

19.The method according to claim 18, further comprising using the determined signal strength for determining the location of the at least one present wireless transceiver unit marked as not ok.

20.The method according to claim 19, wherein receiving the further command message further comprises: 8. receiving a calculated search pattern, and b. providing the calculated search pattern to a user of the wireless transceiver unit. 42

21. .The method of any one of claims 13 - 20, wherein at least one of thesteps of transmitting a presence check acknowledgement andtransmitting a status check message comprises transmitting location information related to the location of the wireless transceiver unit.

22.The method of any one of claims 13 - 21, wherein receiving abroadcasted presence check signal comprises receiving an invite message to join a group list and wherein the step of transmitting a presence acknowledgement comprises the step of accepting the invite.

23.The method of any one of claims 13 - 22, further comprisingautomatically repeating the step of broadcasting the presence check signal including a command message.

24.A method in a transceiver unit comprising a local network transceiver,for checking the status of at least one wireless transceiver unit, the method comprises a presence check comprising: a. broadcasting a presence check signal, using the local networktransceiver, b. listening for a broadcasted presence check acknowledgementfrom at least one wireless transceiver unit, c. upon receipt of a presence check acknowledgement from the atleast one additional capable wireless transceiver unit, creating agroup list of present wireless transceiver units, d. sending a status check message to at least one presentwireless transceiver unit, e. listening for status check message acknowledgements from theat least one present wireless transceiver unit, f. upon receipt of a positive status check messageacknowledgement from the at least one present wireless 43 transceiver unit, updating the group list by marking the at leastone present wireless transceiver unit as ok, andg. upon receipt of a negative status check message acknowledgement, or in the absence of a status check messageacknowledgement, from the at least one present wirelesstransceiver unit, updating the group list by marking the at least one present additional wireless transceiver unit as not ok.

25.A wireless transceiver unit configured to run a status check application,the wireless transceiver unit having a group list ID and being part of agroup list specific to the status check application, the wirelesstransceiver unit comprising a local network transceiver, the wirelesstransceiver unit comprising: a. a local network receiving unit, configured to receive a broadcastpresence check signal including the group list ID and acommand message with instructions to perform presenceverification, and b. a local network transmitting unit, configured to transmit apresence check acknowledgement comprising the group list ID,on the basis of the command message.

26.The wireless transceiver unit according to claim 25, wherein thecommand message further comprises instructions to relay thepresence check signal and wherein: a. the local network transmitting unit is further configured tobroadcast, based on the received command message, thepresence check signal including a second command message, b. the local network receiving unit is further configured to listen forpresence check acknowledgements from at least one additionalwireless transceiver unit, and wherein c. the local network transmitting unit is further configured to, uponreceipt of a presence check acknowledgement from the at least 44 one additional wireless transceiver unit, transmit the presencecheck acknowledgement of the at least one additional wirelesstransceiver to an initiating wireless transceiver unit, using the local network transceiver.

27.The wireless transceiver unit according to any one of claims 24 and 25, wherein: a. the local network receiving unit is further configured to receive a d. status check message, using a local network receiver, the wireless transceiver unit further comprising a prompting unitconfigured to prompt a user of the wireless transceiver unit forpositive or negative status, the local network transmitting unit is further configured to, uponreceipt of a positive status input, transmit a positive status checkmessage acknowledgement, and wherein the local network transmitting unit is further configured to, uponreceipt of a negative status input, or in the absence of a statusinput, transmit a negative status check message acknowledgement.

28.The wireless transceiver unit according to claim 27, wherein the local network transmitting unit is configured to broadcast the status check as an integrated part of the presence check.

29.A computer program product comprising a computer-readable non- transitory storage medium with instructions adapted to carry out the method of any one of claims 1 - 12, 13 - 24 or 25 when executed by a device having processing capability.