WO2008125880A1

WO2008125880A1 - Multiple module co-operation in data distribution systems

Info

Publication number: WO2008125880A1
Application number: PCT/GB2008/050256
Authority: WO
Inventors: Graham Tricker
Original assignee: Hypertag Limited
Priority date: 2007-04-13
Filing date: 2008-04-11
Publication date: 2008-10-23

Abstract

A base station designed to send data simultaneously to users of wireless mobile units is able to service only a limited number of mobiles in a given time. The problem is solved by a base station that has a plurality of transceiver modules (1,2 and 3); means (4) for selecting a module that is not in use and causing it to transmit an enquiry signal inviting mobile units in range to request information; and means (4) for selecting a module that is not in use and causing it to transmit the data to a mobile that has responded. The identity of mobiles that have responded to an enquiry signal are preferably entered in a register (6) which, when empty, triggers the selection of a module to transmit another enquiry signal. When the data has been transmitted to a mobile, that mobile's identity is removed from the register (6). Because all of the modules share a common register of stored mobile identities, the possibility of sending multiple invitations to a single mobile unit is removed. Additionally, because each module is capable of transmitting either an enquiry signal or data to a mobile unit, the efficiency of each module is maximised and so a greater number of the mobile units can be served.

Description

[001] Multiple Module Cooperation in Data Distribution Systems

[002] This invention relates to a communication system of the type in which a base station, which can take the form of an electronic tag, is used to send data to users of wireless mobile units. These tags are used in environments such as on poster panels, festival sites, trade shows, train stations and football grounds to deliver information relevant to that environment. For example a tag on a poster panel might deliver more detailed information concerning a product advertised on the poster. The wireless mobile unit can be a mobile phone, personal digital assistant or other mobile electronic unit.

[003] Known systems of the aforementioned type are often deployed in situations where the number of users is potentially very large, with the result that long delays may be experienced by people wishing to receive content from the station. Examples of such situations are information points at trade shows, music festivals, bus or train stations, or museums at which a significant number of people may wish to receive content in a relatively short period of time. Conventionally, some such systems have used a short range (up to about 10 metres) radio communication system known by the trade mark Bluetooth of Bluetooth SIG, Inc.

[004] The bandwidth of Bluetooth data transmission to consumer mobile devices varies greatly, but can be as low as 20 Kbytes per second and more typically 150 Kbytes per second, with the result that most transfers of digital audio or image content take several seconds, even a minute, to complete. As a result, a data distribution station capable of several simultaneous transfers at the full data rate might at best only be able to service in the region of 10 to 20 mobile devices per minute. For large content files such as video, with correspondingly longer transfer times, this problem becomes much greater. For example, if the data to be transferred is a thirty second video, this might typically take 30 seconds to transfer at a download speed of 150 Kilobytes per second, depending on the mobile device. If there are say 6 mobile devices connected, one of these would have to wait 2.5 minutes before a connection is made or all six devices would face a download lasting 3 minutes. Mobile users are unlikely to tolerate a wait of this length of time.

[005] A simple response to this problem is to provide duplicate wireless servers in each location to cope with the volume of usage. However, if these servers are separate units, this may not be an effective solution, because there is no sharing of information about which consumer devices have been served, and which are still awaiting attention. The result of this can be data being sent repeatedly to some mobile devices, while others are ignored completely.

[006] According to the invention there is provided a radio communication system having a base station comprising:

[007] (a) a store of data to be transmitted to mobile units;

[008] (b) a plurality of transceiver modules;

[009] (c) means for selecting a module that is not in use and causing it to transmit an enquiry signal inviting mobile units in range to request information;

[010] (d) means for selecting a module that is not in use and causing it to transmit the data from the store to a mobile that has responded requesting information.

[011] In a preferred embodiment the system further comprises a register for storing the identities of mobiles to which data is to be transmitted;

[012] a means for entering in the registry, the identity of mobiles that have responded to the enquiry signal in (c);

[013] that the means for selecting a module that is not in use and causing it to transmit an enquiry signal inviting mobile units in range to request information, is responsive to the register being empty; and

[014] that the means in (d) causes the selected module to transmit the data to a mobile identified in the register and to remove the mobile identity from the register.

[015] Because all of the modules share a common register of stored mobile identities, the possibility of sending multiple invitations to a single mobile unit is removed. Additionally, because each module is capable of transmitting either an enquiry signal to fill the register or data to a mobile unit, and is switched between these two functions by a central controller depending upon the status of the register and other modules in the system, the efficiency of each module is maximised and so a greater number of the mobile units can be served.

[016] In a preferable embodiment the radio communication system uses a short range frequency hopping protocol and may also comprises a means for selecting a module that is not in use and causing it to transmit that from the store to a mobile having an identity being in the registry the longest period of time.

[017] The invention will now be described by way of example with reference to the accompanying drawing which shows a block diagram of a radio communication data distribution system constructed in accordance with the invention.

[018] Referring to the drawing there is shown a radio communication data distribution system for incorporation within an electronic tag device at a location accessible to the public. In this example the tag is associated with a marketing poster panel at a bus stop. The system has three transceiver modules 1, 2, 3 in the form of short range wireless Bluetooth® chips. As is conventional in such modules, each has a chip controller IA, 2A, 3A, transmission power controller IB, 2B, 3B and a transceiver unit 1C, 2C, 3C.

[019] The chip controllers IA, 2A & 3 A control the hop sequence of its corresponding transceiver 1C, 2C, & 3C so as to switch, according to a pseudorandom sequence, between different permitted frequencies within a specified frequency range. Each controller also controls the power controller IB, 2B, 2C to dynamically adjust the transmission power of the transceiver either for enquiry, or during connection with a mobile unit. In a standard Bluetooth connection, the transmit powers of the connected devices are dynamic and will fluctuate depending upon the strength of the signal received by the other device. The power level is set by a chip controller IA which instructs the power controller IB. Standard Bluetooth chips are 'factory' set such that the controller can adjust the transmit power to have a range anywhere from between a 1 to 10 meters and beyond. The chip controllers are conventionally pre-programmed to set the power transmission to a maximum during enquiry broadcasts to increase the probability of finding available devices. [020] All three modules 1, 2, 3 are connected to a master controller 4 which:

1. instructs each of the transceiver modules as to whether to transmit in a enquiry mode or to establish a connection with a found mobile device (connection mode), and

2. instructs the data to be downloaded. [021]

[022] Also forming part of the system is a data store 5, such as a magnetic drive, holding information which is to be transmitted to mobile devices, and volatile memory storage 6, such as a RAM which holds the addresses of the mobile devices found during the enquiry. Both the data store 5 and device list 6 are linked to the system via the master controller 4. The master controller can be an embedded processor, a PC or any hardware architecture which supports Bluetooth®.

[023] In this embodiment information stored on the data storage 5 is likely to relate to the poster to which the tag is associated and may include text, pictures, video or audio material. The data storage may hold various different versions of the information which can be selected depending upon the technical specification of the mobile device being serviced.

[024] In operation the master controller 4 continuously scans the modules 1, 2, 3 until it finds one that is not in use. If there are no entries in the register 6 (to be described later) the master controller then sends a command to module 1, 2 or 3 to make a ten second enquiry broadcast. The controller, e.g. IA, of the selected module causes its transceiver Tx/Rx to start an enquiry broadcast across a particular frequency hopping sequence.

[025] Mobile devices which are found within range of this low power enquiry interpret it as an invitation to receive content from the data store 5. If they accept this invitation, a message is transmitted back to the module 1 containing a unique identity code for the mobile together with other information such as the mobile's media display capabilities. The controller 4 stores this information as one item in a list held in a register 6. The mobile devices are stored in the order in which they are found.

[026] The master controller 4 contains data concerning different types of mobile device. If, during its scan of modules 1, 2, 3, it identifies a module not in use when there is at least one entry in the register 6, it selects, from store 6, data suitable for transmission to the mobile specified in that oldest entry. It then deletes the entry and sends the selected data to the identified module with an instruction to transmit it to the specified mobile.

[027] The chip controller (eg. 2A) of the module instructed to transmit the data arranges a hopping sequence (piconet) for each data-sending operation and controls the power control 2B during transmission of the data within the specified power range.

[028] It is likely that at some point during the operation of the tag it will be required to update the information stored within the data store 5 or the firmware of the system. This is particularly necessary when the poster is changed. It may also be wished to adjust the ranges of the power controls of the enquiry broadcast depending on the environmental factors of the location of the tag, e.g. its proximity to a pavement, its accessibility to the public etc.

[029] For this purpose, an authentication store 7 is included. This holds the unique identity or identities of one or more master mobile device(s). When any mobile device is discovered during enquiry, the controller 4 checks its identity for a match with the known identities of mobile devices authorised to act as master devices. If such a match is detected the system is enabled to download information from the master mobile device, relating to firmware and data for the store 5.

[030] Although in the above preferred embodiment the system comprises a register 6, it would be possible to implement the system without a register 6 in which the master controller 4 would upon receiving mobile device information from a inquiry, immediately cause an available module to transmit information from the store 5 to mobile. This would repeat as and when a mobile is found until there are no more available modules. Upon which any subsequently found mobiles would not be responded to nor information about them kept.

[031] In yet another embodiment, the system may include a register though this may not be local to the tag but rather remotely linked to the tag via a wired or wireless network connection.

[032]

Claims

[001] A radio communication system having a base station comprising: (a) a store of data to be transmitted to mobile units; (b) a plurality of transceiver modules; (c) means for selecting a module that is not in use and causing it to transmit an enquiry signal inviting mobile units in range to request information; and (d) means for selecting a module that is not in use and causing it to transmit the data from the store to a mobile that has responded requesting information.

[002] A radio communication system according to Claim 1 having: a register for storing the identities of mobiles to which data is to be transmitted; a means for entering in the registry, the identity of mobiles that have responded to the enquiry signal in (c); that the means for selecting a module that is not in use and causing it to transmit an enquiry signal inviting mobile units in range to request information, is responsive to the register being empty; and that the means in (d) causes the selected module to transmit the data to a mobile identified in the register and to remove the mobile identity from the register.

[003] A radio communication system according to Claim 1 comprising a means for selecting a module that is not in use and causing it to transmit that from the store to a mobile having an identity being in the registry the longest period of time.

[004] A radio communication system according to Claim 1 using a short range frequency hopping protocol.