Patent Publication Number: US-2003224799-A1

Title: Facilitating data transfers with mobile entities via wireless communication hotspots

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to the management of communication resources for facilitating, data transfers with mobile entities via wireless-based communication hotspots.  
       BACKGROUND OF THE INVENTION  
       [0002] Wireless LANs are gaining substantial acceptance as a means for providing connectivity over a restricted area to mobile devices. Whilst there are a number of different wireless LAN architectures and the present invention is not limited to any particular one (or, indeed to wireless LANs), the following description is generally written using the terminology applied in the ANSI/IEEE Standard 802.11 (“Wireless LAN Medium Access Control and Physical Layer Specifications”). More particularly, FIG. 1 of the accompanying drawings illustrates the main components of a wireless LAN using that terminology. Thus, a typical wireless LAN  5  comprises a distribution system  10  that serves to interconnect a number of access points (AP)  11  via a network. Each access point  11  connects with mobile stations (MS)  12  over a wireless medium to form a Basic Service Set  13  (BSS 1  and BSS 2 ). The totality of the basis service sets and the network that interconnects them is called an Extended Service Set (ESS). The wireless LAN may connect with other networks via a portal  14 .  
       [0003] Wireless LANs can be used to provide connectivity over limited areas such as public spaces and publicly-accessible premises, both commercial and noncommercial. These limited areas of connectivity are often referred to as “hotspots” as they generally provide a much higher speed of data transfer to mobile devices than is available via other wireless systems of more general coverage such as the data-capable bearer services provided by cellular radio networks such as GSM.  
       [0004] Whilst such connectivity “hotspots” are presently provided primarily by wireless LANs, other technologies can also be used to provide localised areas of high transfer rates (as compared to the surrounding environment) and as used herein the term “hotspot” is intended to be technology independent, merely indicating that improved data transfer rates are available in localised areas. An example of an alternative technology that can be used to provide a communications hotspot is a system that tracks the movement of a mobile device whilst within a limited range and uses a directional antenna pointing at the device to provide a high data rate link. Another example is the use of a cluster of infrared transceivers within a limited area, adjacent transceivers operating at different frequencies or with different modulations to avoid interference.  
       [0005] A significant drawback to the use of communication hotspots for transferring substantial amounts of data to mobile entities moving through the hotspots is that the dwell time of the entities in any hotspot is limited; in addition, a mobile entity may well not have access rights to use all hotspots through which it passes and even if it has, there may be no available capacity at the time the device is within the hotspot.  
       [0006] It is an object of the present invention to facilitate data transfer to/from mobile entities as they traverse communication hotspots.  
       SUMMARY OF THE INVENTION  
       [0007] According to one aspect of the present invention, there is provided a method of managing communication resources in relation to the transfer of data to/from a mobile entity using wireless-based communications infrastructures of multiple localized communication hotspots traversed by the mobile entity, at least some of the hotspots requiring separate utilization rights to each other, the method comprising the steps of,  
       [0008] (a) predicting progress of the mobile entity;  
       [0009] (b) based on the predicted progress of the mobile entity and its data transfer needs, making a determination about possible desired future utilization by the mobile entity of the communications infrastructure of a particular said hotspot likely to be traversed by the entity; and  
       [0010] (c) in dependence on said determination, obtaining, in advance, utilisation rights for the mobile entity to use said particular hotspot when traversing it.  
       [0011] According to another aspect of the present invention, there is provided a service system for managing communication resources in relation to the transfer of data to/from a mobile entity using wireless-based communications infrastructure of multiple localized communication hotspots traversed by the mobile entity, at least some of the hotspots requiring separate utilization rights to each other, the system comprising:  
       [0012] a first communications subsystem for communicating with the mobile entity;  
       [0013] a second communications subsystem for communicating with the communications infrastructure of said hotspots;  
       [0014] a utilization determination subsystem operative to predict progress of the mobile entity relative to said at least one hotspot, and to make a determination, based on the predicted progress of the mobile entity and its data transfer needs, about possible desired future utilization by the mobile entity of the communications infrastructure of a particular said hotspot likely to be traversed by the entity; and  
       [0015] a management subsystem operative in dependence on said determination, to obtain, in advance, utilisation rights for the mobile entity to use said particular hotspot when the mobile entity comes to traverse that hotspot.  
       [0016] According to a further aspect of the present invention, there is provided a mobile entity comprising:  
       [0017] a communications subsystem for communicating with wireless-based communication infrastructure of localized communication hotspots in order to transfer data to/from the mobile entity;  
       [0018] a utilization determination subsystem operative to predict progress of the mobile entity relative to said at least one hotspot, and to make a determination, based on the predicted progress of the mobile entity and its data transfer needs, about possible desired future utilization by the mobile entity of the communications infrastructure of a particular hotspot likely to be traversed by the entity; and  
       [0019] a management subsystem operative in dependence on said determination, to obtain, in advance, utilisation rights for the mobile entity to use said particular hotspot when the mobile entity comes to traverse that hotspot.  
       [0020] An additional aspect of the invention relates to a computer arrangement for managing communication resources in relation to the transfer of data to/from a mobile entity having wireless-based communications infrastructures of multiple localized communication hotspots traversed by the mobile entity, at least some of the hotspots requiring separate utilization rights to each other, the computer arrangement comprising a processor and a memory for:  
       [0021] (a) deriving a first signal indicative of a prediction of progress of the mobile entity;  
       [0022] (b) deriving a second signal indicative of a possible desired future utilization by the mobile entity of the communications infrastructure of a particular hotspot likely to be traversed by the entity in response to the first signal; and  
       [0023] (c) deriving a third signal indicative of utilisation rights for the mobile entity to use said particular hotspot when traversing it in response to said second signal, the processor and memory being arranged to derive the third signal in advance of the mobile entity entering the particular hotspot.  
       [0024] An added aspect of the invention relates to a memory storing a program for enabling a computer arrangement to manage communication resources in relation to the transfer of data to/from a mobile entity having wireless-based communications infrastructures of multiple localized communication hotspots traversed by the mobile entity, at least some of the hotspots requiring separate utilization rights to each other, the memory being programmed for causing the computer arrangement to:  
       [0025] (a) predict progress of the mobile entity;  
       [0026] (b) based on the predicted progress of the mobile entity and its data transfer needs, determine possible desired future utilization by the mobile entity of the communications infrastructure of a particular hotspot likely to be traversed by the entity; and  
       [0027] (c) in dependence on said determination, obtain, in advance, utilisation rights for the mobile entity to use said particular hotspot when traversing it.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0028] Embodiments of the invention will now be described, by way of non-limiting example, with reference to the accompanying diagrammatic drawings, in which:  
     [0029]FIG. 1 is a diagram of a known wireless LAN architecture;  
     [0030]FIG. 2 is a diagram of a resource-management service system, embodying the invention, for determining future hotspot utilization needs of mobile devices and for managing communication resources accordingly; and  
     [0031]FIG. 3 is a flow chain showing a decision process carried out by the resource management service system of FIG. 2. 
    
    
     BEST MODE OF CARRYING OUT THE INVENTION  
     [0032]FIG. 2 shows a plurality of wireless communication hotspots  21  to  24  each formed, for example, by a wireless LAN infrastructure  25  having a limited coverage area within which suitably equipped and authorised mobile devices  30 A,  30 B (here depicted as vehicle borne) can establish wireless communication with the infrastructure. Each hotspot infrastructure  25  includes a portal providing connectivity to the public internet  20  (or other wide-area data network) and its connected resources  27 ,  28  (typically, respectively content sources and sinks); as a result, a mobile device  30 A,  30 B traversing a hotspot can connect to and exchange data with the internet-connected resources  27 ,  28 . The communications technology employed by the hotspots may vary from one hotspot to another.  
     [0033] In the present case each hotspot  21 - 24  is independently managed and its infrastructure  25  includes a control subsystem  29  with mechanisms, known per se, for restricting usage to authorised mobile devices. Thus, separate utilisation rights are required by a mobile entity to utilize each other. Furthermore, as used herein, reference to a mobile entity having utilisation rights for a particular hotspot does not mean that the mobile entity will necessarily be able to use the hotspot at any particular moment as the resources of the hotspot might be occupied in servicing other entities; however, as will be described below, a mobile entity can reserve (or have reserved for it) communication resources to permit it to communicate at at least a particular data rate.  
     [0034] Thus, in the present embodiment, the control subsystem  29  of each hotspot also includes allocation mechanisms enabling a suitable-embodied mobile device to connect through to the Internet at any selected one of several different data rates (connection speeds) with the resources needed for the selected data rate being made available on a guaranteed basis, at least so far as the resources of the hotspot infrastructure are concerned. In addition, in the present embodiment the control subsystem  29  further includes reservation mechanisms enabling hotspot resources for a particular data rate to be reserved in advance. For convenience, the allocation and reservation of the hotspot resources to provide for a particular data transfer rate, is referred to below as “bandwidth” allocation and reservation.  
     [0035] A resource-management service system  40  communicates with the hotspot infrastructures via the Internet  20  (or any other appropriate channel) to set up hotspot utilization rights and/or reserve bandwidth (transfer data rate) for mobile devices that are registered users of the service system  40  and have a need to use the hotspot communication resources; in the present case, both mobile devices  30 A and  30 B are registered users. While resource management service system  40  is illustrated as including several individual subsystems (i.e., client interface  41 , track and hotspot-crossing prediction unit  44 , future utilisation determination/bandwidth management processing unit  45  and access/bandwidth reservation unit  46 , as well as memories labeled as user data base  42  and hotspot data base  43 ) it is to be understood that these subsystems and memories can be incorporated into a programmed digital computer or processor having a memory storing a (1) program for controlling the subsystems and (2) the data bases.  
     [0036] In the present embodiment, the mobile devices  30 A,  30 B communicate with the service system  40  via a data-capable bearer service of a cellular radio network  35  such as a GSM based PLMN (Public Land Mobile Network) that provides ubiquitous coverage over an area encompassing all the hotspots  21 - 24 .  
     [0037] The service system  40  is arranged to receive information about the movement of each registered mobile device  30 A,B and of its data transfer needs. Based on predictions of what hotspots the mobile devices are likely to traverse, the service system  40  sets up hotspot utilization rights and/or reserves hotspot bandwidth in order to enable the mobile devices to effect the data transfers via the hotspots they traverse on their respective routes. The service system  40  can reserve hotspot utilization and bandwidth for a mobile device prior to the start of data transfer and whilst the device is outside any hotspot. The service system  40  can also determine that a current data transfer is unlikely to be completed during traversal of the hotspot in which the mobile device is currently located; in this case, the service system can either seek to increase the available bandwidth for the data transfer so as to complete it in the current hotspot, or set up utilization rights and/or reserve bandwidth for the mobile device in a next hotspot to be traversed by the device.  
     [0038] A more detailed description of the operation of the service system  40  is given below in respect of example data transfers undertaken by the mobile devices  30 A,B.  
     [0039] Considering first mobile device  30 A, it is assumed that this device has determined that it wishes to download a large content file from a content server  27 —how this determination is made is not relevant for present purposes but may be as a result of browsing the Internet via a data-capable bearer service of the cellular network or on the basis of a predetermined transfer schedule (for example, all new emails are to be downloaded together every hour). Upon determining that a large file is to be downloaded, the mobile device establishes communication with the service system  40  via the cellular network  35  where a client interface  41  first checks with user database  42  that the mobile device is (or belongs to) a registered user of the service system. Location server  36  determines and derives signals indicative of location fixes giving the location of the mobile device  30 , which signals are passed to a track and hotspot-crossing prediction unit  44  of the service system. Location server  36  derives the device location signals in a standard manner from measurements taken by the cellular network infrastructure. Alternatively, the mobile device  30  derives the location fix indicating signals in response to signals from an associated GPS system or from the location server  36 .  
     [0040] The prediction unit  44  uses the received location fixes to predict the progress of the mobile device  30 A and, in particular, to derive a signal indicative of a prediction of the traversal of device  30 A of hotspots known to the service system; data about these hotspots, including geographical coverage data, are stored as signals in database  43 . Unit  44  can simply work on a straight-line extrapolation of the current direction of travel and speed of the mobile device (derived from successive location fixes) to determine and derive a signal indicative of the intersection of the predicted track of the device with hotspot coverage areas. Alternatively, more sophisticated approaches can be used taking account, for example, of route constraints such as would apply to vehicles (i.e. they must follow roads) where it is known or deduced that the mobile is vehicle bone. Use can also be made of histories of previous routes followed by the mobile device  30 A (for example, user database  42  can store signals indicative of frequently followed routes and then seek to correlate the observed track of the mobile device  30 A with such a route in order to predict the future track of the mobile device). Of course, information on the route being followed can also be uploaded from the mobile device  30  to the service system  40 .  
     [0041] On the basis of the predicted programs of the mobile device  30  and the geographic extent of a hotspot in which the mobile device is already located, the prediction unit  44  is further arranged to determine and derive a signal indicative of the length of time that the device is likely to remain within the coverage of the hotspot.  
     [0042] In present example, upon unit  44  determining that the mobile device  30 A is likely to traverse one or more hotspots, unit  44  derives a signal indicative of this fact and the size of the file that the device  30 A wishes to download; unit  44  supplies the signal to processing unit  45  via control functionality of the client interface  41 . Unit  45  also is responsive to signals indicative of the capabilities of the mobile device  30 A either directly from the device itself or from user database  42 .  
     [0043] The processing unit  45  is operative then to make determinations and derive signals indicative of future utilisation of hotspot resources for satisfying the data transfer needs of the mobile device. FIG. 3 is a flow chart illustrating the general process carried out by the unit  45  for this purpose. More particularly, the unit  45  first determines whether the mobile device is currently in a hotspot and transferring data (block  60 ); if, as in the present example, this is not the case, the unit  45  checks the information it has received from unit  44  to see if the mobile device is likely to pass through a hotspot in the future (block  65 ). If the mobile device  30 A is not predicted to pass through a hotspot, the unit  45  causes an alert to be sent to the mobile device  30 A (block  66 ) to warn the device user of this to enable the latter to make a decision as to what alternative action to take (for example, to accept download of the file via a data-capable bearer service of the cellular network  35 , the device having been set up with a default in which such an option is only permitted for files over a certain size with user permission, automatic download only being permitted via hotspots under the organisation of the service system  40 ).  
     [0044] In response to unit  45  determining that the mobile device  30 A is predicted to traverse at least one hotspot  21 - 24  along its route (in this case, hotspot  21 ; see predicted track  31 A in FIG. 2), unit  45  (during operation  67 ) instructs reservation unit  46  to make appropriate utilization rights/bandwidth reservations with the relevant hotspot. In particular, unit  45  supplies a signal to unit  46  indicative of the identity of the mobile device  30 A, the (next) hotspot to be traversed by the device, the likely time of entry of the device into the hotspot, and the data transfer rate that is to be provided. Unit  45  determines the data transfer rate on the basis of the capabilities of the device, the costs associated with various different transfer rates, and the amount of data to be transferred, it being appreciated that a significantly higher cost is generally be considered acceptable if the data transfer can be completed during the traversal of a single hotspot.  
     [0045] The reservation unit  46  then supplies the control subsystem  29  of the relevant hotspot  21  with a signal commanding that control subsystem to set up, in advance, utilization rights for the mobile device  30 A and to reserve resources to enable the device to connect to the Internet at a particular data rate. This reservation is done on the basis of the predicted time of entry of the mobile device into the coverage area of the hotspot; entry within a small margin of that time guaranteeing that the resources are available immediately whereas entry at later or earlier times only guaranteeing that the resources will be available within a certain time delay.  
     [0046] When unit  46  has made the requested reservation, the unit  46  sends a signal back to unit  45 ; the signal unit  46  passes to unit  45  is a signal that is a utilization pass-code specified by the hotspot control subsystem. The unit  46  then supplies a signal to the mobile device  30 A, via the client interface  41 , indicative of the hotspot utilization that has been set up and any pass-code to be used. If the unit  46  is unable to make the desired hotspot resource reservation, the unit  46  is arranged either to negotiate the closest suitable reservation with the hotspot concerned, or else to report back to the unit  45  which modifies its reservation requirements.  
     [0047] In due course, the mobile device  30 A starts to traverse the hotspot  21  and in doing so seeks to gain access to the communication resources of the hotspot in order to establish communication with the content server  27  to effect the desired download. In the present example, it is assumed that the download is successfully established and completed during the traversal of hotspot  21  by the mobile device  30 A.  
     [0048] It will be appreciated that track prediction is not necessarily done on a once-off basis and can, instead, be done repeatedly as each new location fix becomes available or at some other suitable frequency. In this case, the prediction of hotspot crossing and time of arrival at a hotspot can be successively refined and used by the units  45  and  46  to modify the utilization rights and bandwidth reservations made for the hotspot resources. In addition, the data transfer requirements of the mobile device  30 A, B frequently change with time to cause changes in the hotspot utilization and bandwidth reservations.  
     [0049] This updating of track prediction and data transfer needs can go on not only as the mobile device  30 A progresses towards a hotspot, but also during the data transfer process once the mobile device has entered a hotspot coverage area and initiated a data transfer. In this case, as already mentioned above, the unit  44  is arranged to determine the time remaining in the hotspot based on a predicted track. Now when the unit  45  runs the FIG. 3 process, since the device  30 A is within a hotspot and effecting a data transfer, unit  45  exits block  60  to block  61  where it determines whether, having regard to the remaining time in the hotspot for the device, there is sufficient time to complete the data transfer at the current data rate; if this is the case, unit  45  takes no action, whereas if there is insufficient time to complete the transfer, the unit  45  goes on to check (block  62 ) whether a different (higher) data transfer rate (transfer bandwidth) can be set. If this is not the case, the unit  45  proceeds to block  65  where it checks to see if other hotspots are on the predicted track of the mobile device, as already described above. If, however, unit  45  determines during block  62  that a higher data transfer rate can be set, then unit  45  determines during operation  63  as to whether the higher transfer rate would result in completion of the data transfer. If operation  63  determines this is so, unit  45  increases the data transfer rate (step  64 ), whereas otherwise the unit proceeds to block  65 .  
     [0050] Increasing the data transfer rate may be something that lies within control of the mobile device  30 A without the need for the service system to contact the control subsystem  29  of the hotspot concerned (hotspot  21  in the present example); in this case, the service system  40  simply supplies a signal to the mobile device that device  30 A should go to a higher transfer rate and the device proceeds to do so in cooperation with the infrastructure of the hotspot. However, in order to achieve a higher data transfer rate, unit  45  supplies to unit  46  a signal commanding unit  46  to contact the control subsystem of the hotspot to set up the increased transfer rate.  
     [0051] As regards the mobile device  30 B shown in FIG. 2, this mobile device is shown as having a predicted track  31 B that takes it through two hotspots  21  and  22 . In this example, it is assumed that the mobile device  30 B wishes to upload a data file to a content sink  28  starting at a particular time. Either at this scheduled upload time or a short while beforehand, the mobile device  30 B contacts the service system  40  to set up the transfer via the hotspots to be traversed by the device. The service system  40  then carries out the steps already described to set up transfer via the hotspot  21 . In due course, the mobile device  30 B enters the coverage area of hotspot  21  and initiates data upload. As the mobile device  30 B traverses the hotspot  21 , further determinations made by the service system  40  as to the hotspot utilisation requirements of the device indicate that the data upload will not be completed during the current traversal of hotspot  21 , either at the current data transfer rate or at any available higher rate. The service system  40  then proceeds to determine that the device  30 B is also likely to traverse hotspot  24  and accordingly makes utilization and bandwidth reservations with that hotspot for completion of the data transfer. If the hotspot control subsystem  29  needs to know how much data is to be transferred, then the unit  45  makes a prediction based on the amount of data remaining to be transferred and the predicted time remaining in hotspot  21 .  
     [0052] Rather than the unit  45  operating on the basis of only making reservations for one hotspot ahead of the current position of the mobile device, unit  45  can be arranged to reserve resources in all hotspots predicted to be traversed by the mobile device and needed to complete a particular data transfer. Thus, prior to the mobile device  30 B entering hotspot  21 , the unit  45  can be arranged to reserve utilization and bandwidth in both hotspots  21  and  22 .  
     [0053] Where a data transfer is interrupted by a mobile device leaving a hotspot, then the endpoints of the transfer use any suitable mechanism enabling the transfer to be subsequently resulted at the point where it was interrupted; such mechanisms are currently widely used for Internet downloads particularly for users using unreliable, low data rate, access connections.  
     [0054] It will be appreciated that many variants are possible to the above-described embodiments of the invention. For example, the reservation unit  46  can be arranged to make utilization and/or bandwidth reservations on the basis of the needs of all devices currently using the service system. Thus, utilization and bandwidth are not reserved for particular devices but as a whole for all registered devices. The reservations made are preferably not just an aggregate of the individual device needs but, instead, take account on a statistical basis of the actual usage needs likely to result from the predictions. Thus, utilization rights may be reserved for only 90% of the mobile devices predicted as likely to traverse a particular hotspot because statistically it had been found that only in exceptional circumstances did more than 90% of those devices actually do enter the hotspot with an unsatisfied data transfer need. It will be appreciated that such a statistical-weighting reservation mechanism preferably takes account of the likelihood of a device keeping to its predicted track and a simple measure that can be used in this case is the distance of the device from the hotspot—the greater the distance, the greater the possibility of the device changing direction and not traversing the hotspot. Thus, if all devices predicted as having a future utilization need for a hotspot are near to entering the hotspot, then the statistical-weighting reservation mechanism should reserve nearly 100% of the resources predicted as being needed; in contrast, where the mobile devices are all at some distance from the hotspot, then the statistical-weighting reservation mechanism can be arranged to reserve, for example, only 80% of the resources predicted as necessary.  
     [0055] Although in the above-described embodiment, the mobile devices use an ubiquitous communications system (for example, cellular network  35 ) to communicate with the service system, it is alternatively possible simply to use the connectivity provided by the hotspots assuming that the mobile devices have at least low data rate utilization rights to these hotspots for connecting through them to the service system  40 . In this case, it can be useful to arrange for the content sources/sinks  27 ,  28  to inform the service system whenever a data transfer is interrupted before its completion, the service system then having a positive indication that the mobile device has exited a hotspot. It is alternatively possible to arrange for the hotspot control system itself to monitor data transfer progress and indicate to the service system when an incomplete transfer is interrupted.  
     [0056] Where a mobile device has connectivity to an ubiquitous communications service such as provided by a data-capable bearer service of a cellular radio network  35 , then this service can be used to continue a data transfer between hotspots, the data transfer being handed over from a hotspot connection to the bearer service as the mobile device leaves the hotspot and being handed over again to the next hotspot connection when established.  
     [0057] The functionality of the service system (other than the predicted-utilization aggregation and statistical-weighting mechanisms mentioned above) can be incorporated into a mobile device so that the device itself takes care of reserving the resources it predicts that it will need in the future.  
     [0058] It will be appreciated that two or more hotspots can be jointly managed on the basis that the right to utilize one of the hotspots is also a right to utilize the other hotspots that are under the same management so that utilization rights for these jointly-managed hotspots need only be obtained once. Furthermore, a hotspot may not have any provision for allocating bandwidth and simply controls utilization; in this case, it is only required to obtain utilization rights to the hotspot.  
     [0059] Although in the above-described embodiment the remote entity with which the mobile device  30  is in communication is an internet-connected resource, it is to be understood that the remote entity could be connected directly to the communications infrastructure of a hotspot or connected to any other communications system accessible via the hotspot(s).