GB2514548A

GB2514548A - Method of configuring a high-frequency radio module, associated multiband radio communication device and system

Info

Publication number: GB2514548A
Application number: GB1309460.2A
Authority: GB
Inventors: Patrice Nezou; Pascal Viger; Francois Thoumy
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2013-05-27
Filing date: 2013-05-27
Publication date: 2014-12-03
Also published as: GB201309460D0

Abstract

A method of configuring a high-frequency radio module 101, 111 and directional antenna 103, 113 of a multiband radio communication device 100, 110 comprises estimating a location of a neighbouring multiband radio communication device 110, 100 in a wireless network 10, using a discovery procedure over a low-frequency band (generally the 5-GHz band), and performing an antenna discovery procedure, over a high-frequency band (generally the 60-GHz band), to align a directional antenna 103, 113 of the high-frequency radio module 101, 111 with the neighbouring multiband radio communication device 110, 100. The antenna discovery procedure is restricted to an angular range surrounding the estimated location of the neighbouring multiband radio communication device 110, 100. The location of the neighbouring multiband radio communication device 110, 100 may be estimated from triangulation measurements obtained from the discovered neighbouring multiband radio communication device 110, 100, such as round-trip-time-based measurements between the discovered neighbouring multiband radio communication device 110, 100 and three or more other radio communication devices 121, 131.

Description

I

METHOD OF CONFIGURING A HIGH-FREQUENCY RADIO MODULE,

ASSOCIATED MULTIBAND RADIO COMMUNICATION DEVICE AND SYSTEM

FIELD OF THE INVENTION

The present invention relates generally to radio networks and more specifically to a method aiming at configuring a high-frequency radio module and directional antenna therein of a multiband radio communication device. The invention also relates to such a multiband radio communication device and corresponding wireless communication system.

BACKGROUND OF THE INVENTION

Promising wireless communication networks operate at high frequencies.

They have been mainly developed to provide solutions to multimedia applications that require sending or transmission of high-rate video data over a communication network for display at a displaying device.

Such promising networks gradually increased operating frequencies over time in the range of several GHz and recently of even higher frequencies.

For example, current 802.11 (IEEE 802.11 Task Group) wireless communication systems use the 57-66 GHz millimetre wave unlicensed spectrum, referred to as 60 GHz millimetre wave technology or 60 GHz band to obtain higher bitrate than with the 2.4 GHz and 5 GHz radio bands.

However, the wireless communication systems based on the 60-GHz millimetre wave technology are highly sensitive to perturbations such as shadowing or interferences, or to fading phenomena, which phenomena may be due to the presence of an unexpected obstacle on the transmission path. Given these perturbations and phenomena, the transmission error rate, i.e. the ratio of transmitted packets that are actually received with error by a receiving device compared to the number of transmitted packets, may increase substantially.

As a result, unless transmission power levels are substantially increased (which is not often permissible), communication ranges for wireless devices (or "nodes" or "stations") operating at these higher frequencies are substantially reduced.

In this context, the use of directional antennas in the 60 GHz wireless devices has been contemplated to mitigate the above problems.

Directional antennas are known to oppose to omni-directional antennas.

Publication US 2010/014502 describes a system and a method for wireless communication over multi-rate channels wherein source and destination devices have directional antennas to establish a first channel with a first frequency and a first range.

They also use a second channel that is omni-directional with a second frequency lower than the first frequency and a second range greater than the first range.

The source device may send, over the second channel to the destination device, a request for data transmission via the first channel. The destination device may send, over the second channel to the source device, an approval for the data transmission.

At transmitting wireless communication devices, directional antennas radiate greater radio wave power in one or more specific directions, to form point-to-point wireless links. This provides a reduced beamwidth along such specific directions or angles in the transmitting or broadcasting antenna pattern. In contrast, the omni-directional antennas radiate radio wave power uniformly in all directions (angles) of one plane of the antenna pattern.

For a given transmission power, this results for the directional antenna in having a higher gain along the one or more specific directions. This gives the impression that the transmission power level has been increased, thus reducing perturbations or fading phenomena due to unexpected obstacles.

Due to reciprocity, the same effects are obtained at receiving wireless communication devices: the reception power level appears to have been increased along the one or more specific directions of the directional antennas.

By selecting sufficiently narrow beamwidths of directional antennas (i.e. with sufficient antenna gains), wireless communication devices are able to operate at high-frequency bands while still maintaining an acceptable communication range (with reliability and throughput of data transmission) despite unexpected obstacles. Point-to-point high-frequency wireless links performed by directional antennas are known to be of high data rate, of low probability of exploitation and of low probability of interception.

An issue with directional antennas is the setting-up or configuration of the radio module handling the antenna, and in particular the alignment of the antenna (along one specific direction of high sensitiveness) with the antenna of another wireless communication device in the neighboring, to form a point-to-point wireless link. Indeed, even if two wireless devices desiring to communicate one with the other belong to the same communication cell (i.e. are within a communication range defined by the high-frequency band), they cannot discover one each other as long as their directional antennas do not align one with each other.

A neighbour discovery process or procedure has been developed to achieve such configuration from the two wireless communication devices.

A conventional neighbour discovery procedure over the 60 GHz band of a wireless network includes a first step of determining the most appropriate angle or direction to be used by the transmitting device when the receiving device is in an omni-mode reception state. The neighbour discovery procedure then includes a second step which is the reverse of the first step, i.e. with a view of determining the most appropriate angle or direction to be used by the receiving device.

However, the conventional neighbour discovery procedure may take a long time to set-up the appropriate angle or direction for all the wireless communication devices within a 60 GHz cell, in particular because each possible angle or direction of the antenna pattern must be considered for each device of each pair of devices. This long-term configuration results in high power consumption at the wireless communication devices.

As a consequence, there is a need to improve the configuration of the high-frequency radio module in a multiband radio communication device of a wireless network. In this context, the present invention has been devised to address at least one of the foregoing concerns, to provide such improved configuration process.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a method of configuring a high-frequency radio module in a multiband radio communication device of a wireless network, comprising: estimating a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over a low-frequency band (generally the 5-GHz band) of the wireless network; performing an antenna discovery procedure over a high-frequency band (generally the 60-GHz band) of the wireless network, to align a directional antenna of the high-frequency radio module with the neighboring multiband radio communication device, wherein the antenna discovery procedure is restricted to an angular range surrounding the estimated location of the neighboring multiband radio communication device.

Correspondingly, according to a second aspect of the invention, there is provided a multiband radio communication device of a wireless network, comprising: a low-frequency radio module; a high-frequency radio module including a directional antenna; a neighbor determination and localization module configured to estimate a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over a low-frequency band of the an antenna discovery module configured to perform an antenna discovery procedure over a high-frequency band of the wireless network, to align the directional antenna of the high-frequency radio module with the neighboring multiband radio communication device, wherein the antenna discovery module is further configured to restrict the antenna discovery procedure to an angular range surrounding the estimated location of the neighboring multiband radio communication device.

According to a third aspect of the invention, there is provided a wireless communication system comprising a plurality of multiband radio communication devices; wherein each multiband radio communication device is as defined above.

The resource-demanding antenna discovery procedure is lightened compared to the techniques of the prior art and the configuration of antenna in the high-frequency radio module of the communication devices can thus be performed faster and at lower costs, saving power consumption for the high-frequency link.

The lightening is achieved according to the invention by performing a pre-discovery over the low-frequency band of the wireless network in order to pre-tune the antenna discovery procedure over the high-frequency band. This reduces the angular range that the antenna discovery procedure has to scan.

To be more precise, the pre-discovery over the low-frequency band makes it possible to obtain or estimate rough or coarse positions of the neighboring devices.

The antenna discovery procedure can then be limited to discover neighboring devices at angles or directions around the estimated positions.

Further features of embodiments of the invention are defined in the dependent appended claims and are explained below in terms of method features.

In one embodiment, the method further comprises deriving a level of transmission power to be used during the discovery procedure over the low-frequency band from a communication range defined for the high-frequency band of the wireless network. The communication range may be user-defined, possibly as a transmission power level, too. In practice, the obtained transmission power level will cover a geographic cell or area vaster than the geographic cell originally defined by the communication range for the antenna discovery over the high-frequency band.

This provision thus makes it possible to tune the transmission power level to ensure that the neighbour discovery procedure over the low-frequency band discovers at least all the wireless devices the antenna discovery procedure over the high-frequency band would normally discover.

In another embodiment of the invention, estimating a location of at least one neighboring multiband radio communication device comprises obtaining a list of neighboring devices from the discovery procedure over the low-frequency band, obtaining triangulation measurements from the discovered neighboring multiband radio communication device, and determining an estimate of location of the neighboring multiband radio communication device from the triangulation measurements. Of course, such process is performed similarly with any neighboring multiband radio communication device that may be discovered using the low-frequency band discovery procedure.

This provision makes it possible to obtain an estimate of neighbor location without increasing power consumption and traffic over the high-frequency band of the network.

It is interesting to note that any low-frequency single-band radio communication device may play an active role in this process, for example by participating in round-trip time measurements to obtain three or more triangulation measurements for the discovered neighboring multiband radio communication device.

According to a particular feature, part or all of the triangulation measurements are round-trip-time-based measurements between the discovered neighboring multiband radio communication device and three or more other radio communication devices, possibly including one or more single-band radio communication devices.

According to a particular feature, one or more single-band radio communication devices configured to communicate over the low-frequency band are discarded from the obtained list of neighboring devices in order to determine a location of only neighboring multiband radio communication devices.

This provision reduces the load of processing. It is justified by the fact that only multiband radio communication devices are then involved in the antenna discovery procedure over the high-frequency band.

According to another particular feature, the high-frequency band of the wireless network is short-ranged and the low-frequency band of the wireless network is long-ranged; and one or more neighboring devices of the obtained list that are beyond a communication range of the high-frequency band are discarded from the obtained list. This provision is to discard neighboring devices that are out-of-reach of the multiband radio communication device being configured. This is because the latter will be unable to perform an antenna discovery procedure with such unreachable devices.

Thanks to this provision, the processing at the multiband radio communication device being configured is further reduced.

In one embodiment of the invention, the angular range is defined as the aperture of a right circular cone coaxial (i.e. aligned) with a straight line between the multiband radio communication device and the estimated location of the neighboring multiband radio communication device. This is because there is no direction around the estimated location that is more probable than others. The right circular cone thus defines a bundle of directions around the straight line, which directions are then processed during the antenna discovery procedure over the high-frequency band.

According to a particular feature, the aperture defining the angular range for the antenna discovery procedure does not depend on the distance between the multiband radio communication device and the estimated location of the neighboring multiband radio communication device. This is to make it possible to have the same angle range to be traversed around the estimated location during the antenna discovery procedure, whatever the distance between the multiband radio communication device to be configured and the neighboring device considered.

In particular, the aperture defining the angular range is equal to 2 * a all around the straight line, where a = cos1 (----), a being a corrective parameter, for instance a = 0,2 to reflect a maximum of 20% of measurement uncertainty in the discovery process over the low-frequency band.

In some variants, apertures depending on the distance between the multiband radio communication device and the estimated location of the neighboring multiband radio communication device may be contemplated to provide varying angle range to be traversed during the antenna discovery procedure.

In another embodiment of the invention, the method is performed at the multiband radio communication device. Indeed, the two discovery procedures can be initiates by the same device that wants to configure itself.

In yet another embodiment of the invention, the discovery procedure over the low-frequency band involves single-band radio communication devices configured to communicate over the low-frequency band. Such single-band radio communication devices may advantageously participate to establish triangulation measurements with a view of obtaining the location of the neighboring multiband radio communication device.

Another aspect of the invention relates to a non-transitory computer-readable medium storing a program which, when executed by a microprocessor or computer system in a multiband wireless communication device of a wireless network, causes the device to perform the steps of: estimating a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over a low-frequency band of the wireless network; performing an antenna discovery procedure over a high-frequency band of the wireless network, to align a directional antenna in a high-frequency radio module of the multiband wireless communication device with the neighboring multiband radio communication device, wherein the antenna discovery procedure is restricted to an angular range surrounding the estimated location of the neighboring multiband radio communication device.

The non-transitory computer-readable medium may have features and advantages that are analogous to those set out above and below in relation to the method, device and system, in particular that of improving the discovery procedure over high-frequency band of the wireless network.

Another aspect of the invention relates to a method of configuring a high-frequency radio module in a multiband radio communication device of a wireless network substantially as herein described with reference to, and as shown in, Figure 4; Figures 4 and 5: Figures 4, 5 and 6; and Figures 4, 5, 6 and 7 of the accompanying drawings.

Yet another aspect of the invention relates to a multiband radio communication device of a wireless network substantially as herein described with reference to, and as shown in, Figure 3 of the accompanying drawings.

Yet another aspect of the invention relates to a wireless communication system substantially as herein described with reference to, and as shown in, Figures 1 and 3 of the accompanying drawings At least parts of the method according to the invention may be computer implemented. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects which may all generally be referred to herein as a "circuit", "module" or "system". Furthermore, the present invention may take the form of a computer program product embodied in any tangible medium of expression having computer usable program code embodied in the medium.

Since the present invention can be implemented in software, the present invention can be embodied as computer readable code for provision to a programmable apparatus on any suitable carrier medium, for example a tangible carrier medium or a transient carrier medium. A tangible carrier medium may comprise a storage medium such as a floppy disk, a CD-ROM, a hard disk drive, a magnetic tape device or a solid state memory device and the like. A transient carrier medium may include a signal such as an electrical signal, an electronic signal, an optical signal, an acoustic signal, a magnetic signal or an electromagnetic signal, e.g. a microwave or RF signal.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, and with reference to the following drawings in which: Figure 1 illustrates a wireless communication system 10 for implementation of the invention; Figure 2 is a block diagram illustrating components of a communicating device in which embodiments of the invention may be implemented; Figure 3 illustrates function blocks of a multiband radio communication device; Figure 4 is a flowchart illustrating general steps of configuring a high-frequency radio module in a multiband radio communication device according to embodiments of the invention; Figure 5 is a flowchart illustrating steps of a neighbor determining step of Figure 4; Figure 6 is a flowchart illustrating steps of a neighbor localizing step of Figure 4; and 1*.

Figure 7 illustrates a modeling of localization error based on a right circular cone.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention provides a method of configuring a high-frequency radio module in a multiband radio communication device of a wireless network, and a corresponding multiband radio communication device.

A multiband radio communication device is a communication device which has capacities to communicate over two or more radio bands of the wireless network with other communication devices. In the description below, it is mainly made reference to only two radio bands, one being of low-frequency relatively to the other one which is of "high-frequency", although the devices may implement more radio bands.

Figure 1 illustrates a wireless communication system 10 for implementation of the invention.

The wireless communication system 10 defines a wireless network of several wireless communication nodes or stations" or devices.

In the wireless network, two or more wireless communication devices use a dual radio channel 60 GHz and 5 GHz. They are named multiband radio communication devices. In the Figure, devices 100 and 110 are multiband radio communication devices, each having a 60 GHz radio module (respectively references 101 and ill) and a S GHz radio module (respectively references 102 and 112) to communicate respectively over a 60 GHz channel 140 and a 5 GHZ channel 150.

The wireless network may implement the 802.11 standards: 802.llad for the 60 GHz channel 140 and 802.1 In for the S GHz channel 150.

Multiband radio communication device 100 can be a video source and multiband radio communication device 110 can be a display device to display video data supplied by the video source 100. In this context, the two multiband radio communication devices exchange data packets through the 60 GHz channel 140, which data packets may be dropped or corrupted.

To provide the 60 GHz channel 140, the two multiband radio communication devices have to configure their 60 GHz RF (radio frequency) modules to align their directional antennas one with the other (as shown schematically by the beam 103 and 113 in the Figure).

An object of the invention as described below is to provide a method of configuring such 60 GHz RF modules, in particular of determining an angle for the directional antennas to obtain alignment thereof In embodiments of the invention, the wireless communication system 10 may include single-band radio communication devices that are configured to communicate over the low-frequency band of the wireless network, that is the 5GHz band in the example of the Figure. Wireless devices 120 and 130 of Figure 1 are single-5GHz-band radio communication devices, each equipped with an associated GHz RF module (121 and 131 in the Figure).

Due to the omni-directionality of their 5 GHz-band antennas, the devices (including multiband and single-band radio communication devices) can communicate one with each other through their respective 5 GHz RF module, over the 5 GHz channel 150.

According to the invention, this capability to communicate over the 5 GHz channel 150 is used by any of the multiband radio communication devices to trigger and perform a rough device discovery over that channel 150. This is to estimate a location of one or more neighboring multiband radio communication devices in the wireless network, using a discovery procedure over the 5-GHZ band (i.e. low-frequency band) of the wireless network.

Rough or coarse geographical positions (locations) of the wireless devices (including multiband and single-band) are obtained with the rough device discovery, for example (xl,yl,zl)for device 100, (x2,y2,z2) for device 130, (x3,y3,z3) for device 120 and (x,y,z) for device 110. The geographical locations are defined with respect to a relative coordinate system centered onto the device to be configured (which triggered the discovery). In a variant, an absolute coordinate system for the whole wireless communication system 10 can be used. Change of coordinate system is conventionally apprehended by the man skilled in the art, and will thus not be further developed herein.

Figure 2 schematically illustrates a communicating device 300, any of devices 100, 110, 120 and 130 of Figure 1, whatever they are transmitters or receivers. As to devices 100 and 120, they are configured to implement at least one embodiment of the present invention to configure itself, namely to align its directional antenna of the 60 GHz RF module 101 or 111.

The communicating device 200 may be a device such as a micro-computer, a workstation or a light portable device. The communicating device 200 comprises a communication bus 213 to which there are preferably connected: -a central processing unit 211, such as a microprocessor, denoted CPU; -a read only memory 207, denoted ROM, for storing computer programs for implementing the invention; -a random access memory 212, denoted RAM, for storing the executable code of methods according to embodiments of the invention as well as the registers adapted to record variables and parameters necessary for implementing methods according to embodiments of the invention; and -at least one communication interlace 202 including a low-frequency (5 GHz) radio module and a high-frequency (60 GHz) radio module equipped with a directional antenna. The communication interlace 202 is connected to the radio communication network, in particular to a high-frequency communication channel (140 in Figure 1) and/or a low-frequency communication channel (150 in Figure 1), for example a wireless communication network according to the 802.11 protocols described above. Any data packet is written to the network interlace for transmission on these channels or is read from the network interlace for reception from these channels, under the control of a software application running in the CPU 211.

Optionally, the communicating device 200 may also include the following components: -a data storage means 204 such as a hard disk, for storing computer programs for implementing methods according to one or more embodiments of the invention; -a disk drive 205 for a disk 206, the disk drive being adapted to read data from the disk 206 or to write data onto said disk; -a screen 209 for displaying decoded data and/or serving as a graphical interface with the user, by means of a keyboard 210 or any other pointing means.

The communicating device 200 can be connected to various peripherals, such as for example a digital camera 208, each being connected to an input/output card (not shown) so as to supply data to the communicating device 200.

The communication bus provides communication and interoperability between the various elements included in the communicating device 200 or connected to it. The representation of the bus is not limiting and in particular the central processing unit is operable to communicate instructions to any element of the communicating device 200 directly or by means of another element of the communicating device 200.

The disk 206 can be replaced by any information medium such as for example a compact disk (CD-ROM), rewritable or not, a ZIP disk or a memory card and, in general terms, by an information storage means that can be read by a microcomputer or by a microprocessor, integrated or not into the apparatus, possibly removable and adapted to store one or more programs whose execution enables a method according to the invention to be implemented.

The executable code may be stored either in read only memory 207. on the hard disk 204 or on a removable digital medium such as for example a disk 206 as described previously. According to a variant, the executable code of the programs can be received by means of the communication network 140/150, via the interface 202, in order to be stored in one of the storage means of the communicating device 200, such as the hard disk 204, before being executed.

The central processing unit 211 is adapted to control and direct the execution of the instructions or portions of software code of the program or programs according to the invention, which instructions are stored in one of the aforementioned storage means. On powering up, the program or programs that are stored in a non-volatile memory, for example on the hard disk 204 or in the read only memory 207, are transferred into the random access memory 212, which then contains the executable code of the program or programs, as well as registers for storing the variables and parameters necessary for implementing the invention.

In this embodiment, the apparatus is a programmable apparatus which uses software to implement the invention. However, alternatively, the present invention may be implemented in hardware (for example, in the form of an Application Specific Integrated Circuit or ASIC).

Figure 3 is a block diagram schematically illustrating the architecture of a multiband radio communication device 300 (i.e. 100 or 110 of Figure 1) adapted to carry out, at least partially, the invention. As illustrated, multiband device 300 comprises a physical (PHY) layer block 303, a MAC layer block 302, and an application layer block 301.

The PHY layer block 303 (here a 802.11 standardized PHY layer) has the task of formatting and sending or receiving data packets over the radio media 140 and 150. Such data packets can be of the RIS type or the CTS type well known in the art.

The PHY layer block 303 includes a 60 GHz RF (radio frequency) module 305 (101 or 111 in Figure 1) equipped with a directional antenna (103 or 113 in Figure 1) to communicate over the 60 GHz channel 140, which directional antenna is to be configured, i.e. well oriented, according to the teachings of the present invention. The PHY layer block 303 also includes a 5 GHz RF (radio frequency) module 304 (102 or 112 in Figure 1) equipped with an omni-directional antenna to communicate over the 5 GHz channel 150.

The MAC layer block 302 comprises a standard MAC 802.11 layer 306 and three additional blocks 307 to 309 for carrying out, at least partially, the invention. The MAC layer block 302 may be implemented in software, which software is loaded into RAM 212 and executed by CPU 211.

The MAC layer block 302 includes a neighbor determination and localization module configured to estimate a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over the 5 GHz band 150 of the wireless network.

This neighbor determination and localization module is schematically represented by blocks 307 and 308.

Block 307 is a neighbor determination module in charge of determining a list of wireless devices neighboring device 300 in the 50Hz band 150. In embodiments of the invention, the list of neighboring devices is obtained from a discovery procedure over the low-frequency band.

Block 308 is a neighbor localization module in charge of localizing, i.e. estimating a geographical position, of the 5GHz band neighbors in the obtained list. In other words, block 308 receives as input the list generated by block 307.

Since the discovery procedure over the 5 0Hz channel may discover the single-band radio communication devices 120 and 130, embodiments of the invention may provide that one or more single-band radio communication devices configured to communicate over the 50Hz (i.e. low4requency) band are discarded from the obtained list of neighboring devices in order to determine a location of only neighboring multiband radio communication devices. This reduces the computation of localization.

The MAC layer block 302 also includes an antenna discovery module (block 309 in the Figure) configured to perform an antenna discovery procedure over the 60 GHz (i.e. high-frequency) band of the wireless network, to align the directional antenna of the high-frequency radio module with the neighboring multiband radio communication device.

The antenna discovery module 309 may be a conventional 60 0Hz antenna discovery module that has been modified and configured to restrict the antenna discovery procedure to an angular range surrounding the estimated location of the neighboring multiband radio communication device. In other words, the antenna discovery module 309 received as input the rough or coarse location of multiband devices as estimated by the neighbor determination and localization module described above, in particular as output by block 308.

Turning now to Figure 4, a method of configuring a high-frequency radio module in a multiband radio communication device of a wireless network, according to embodiments of the invention is described. The method is implemented within a multiband radio communication device 100 or 110 (reference device) that wants to configure itself for communication with other devices over the 60 GHz channel 140, i.e. wants to set up the best angle to its 60 GHz antenna 103 or 113.

Of course, the same process can be performed, simultaneously or not, by other multiband radio communication devices that want to configure themselves.

Steps 400-420 perform a first action of estimating a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over a low-frequency band (generally the 5-GHz band) of the wireless network. This comprises step 400 of determining a 60 GHz band transmission range, step 410 of determining neighbors and step 420 of localizing the neighbors. The steps are detailed below with reference to Figures 5-7.

Step 430 explicitly shows that the outcome of the above steps 400-420, i.e. an estimate of multiband device positions is provided as an input to step 440, in particular to the antenna discovery module 309.

Step 440 is a second main action of the method according to the invention, that performs an antenna discovery procedure over a high-frequency band (generally the 60-GHz band) of the wireless network, to align a directional antenna of the high-frequency radio module with the (reference) neighboring multiband radio communication device. Thanks to step 430, the antenna discovery procedure of step 440 may be restricted to an angular range surrounding the estimated location of the (reference) neighboring multiband radio communication device.

With more details, step 400 consists in defining a transmission or communication range in the high-frequency band, i.e. the 60 GHz band. This communication range depends on the transmission power and defines how far can be two devices intending to communicate one with the other. In other words, it defines the 0Hz network cell that the devices want to set up. Selecting an appropriate communication range is thus an important issue.

The communication range can be predefined, set by the user or evaluated during an initialization phase of the device to optimize the number of potentially detectable neighboring 60 0Hz devices. One skilled in the 60-GHz-network art already knows how to define such communication range.

Upon receiving the 60 GHz communication range from step 400. the neighbor determination module 307 performs step 410 to adapt the transmission power in the 5 0Hz band depending on the 60 0Hz communication range and then to discover all the 5 GHz devices (including single-band and multiband devices) in this communication range.

Figure 5 illustrates an exemplary implementation of step 410.

The communication range for the 60 0Hz band 140 is obtained at step 500 from step 400 of Figure 4.

Step 510 consists in adapting the transmission power in the 5 GHz band depending on the received 60 0Hz communication range. This is done by deriving a level of transmission power to be used during the discovery procedure over the 5 GHz band (described below) from the communication range defined for the 60 0Hz band of the wireless network.

In details, the received communication range makes it possible to determine a radius of an area for the discovery procedure over the 5 0Hz band, from the communication range. This is the area in which the 5 GHz devices can be discovered.

Using the determined radius and for instance the FrUs equations well-known in the prior art, the 5 0Hz transmission power can be determined (based also on predefined antenna gains and predefined minimal reception power), i.e. adapted to the 60 0Hz communication range.

Preferably, this 5 0Hz transmission power level should correspond to a communication range that is the same or greater as/than defined for the 60 0Hz band.

In a variant, step 510 could be simplified to only set a 5 0Hz transmission power level at a value that provides a reasonably broad range of coverage. Such variant could then be combined with a discarding process based on the distance between the devices as explained below.

Next to step 510 providing the 5 GHz transmission power level, a neighbor discovery procedure over the 5 0Hz band 150 is triggered and conducted by the considered or reference" multiband radio communication device, at step 520.

This neighbor discovery procedure uses 802.11-standardized RTS/GTS messages. For example, the reference multiband radio communication device that wants to discover its neighbors first sends a 802.11-standard multicast RTS message.

According to the same standard, all the neighbors (i.e. devices that receive the RTS message) answer by sending a 802.11-standard CTS message. The reference multiband radio communication device thus receives and stores locally such CIS answers, making it possible for the reference device to generate a list of neighbors (step 530).

One directly understands that a list of neighbors is thus obtained by each multiband radio communication device that wants to configure itself. The list may comprise both multiband and single-5GHz-band radio communication devices.

Back to Figure 4, upon receiving the list of neighbors from step 410. the neighbor localization module 308 performs step 420 to determine, i.e. estimate, a rough or coarse geographical position or location of neighboring devices in the list received.

Figure 6 illustrates an exemplary implementation of step 420.

In one embodiment, one or more, preferably all, single-band radio communication devices configured to communicate over the 5 0Hz band are discarded from the obtained list of neighboring devices. This is to avoid performing step 420 on such single-band radio communication devices because coarse location of these single-band devices is not needed in the second action (antenna discovery procedure over the 60 0Hz channel) of the method according to the invention.

Such discarding reduces the processing at step 420.

This discarding step can be performed indifferently at the end of the process of Figure 5 or at the very beginning of the process of Figure 6 as explained here.

To achieve the discarding, the reference multiband radio communication device may store in memory a network profile that defines the band or bands used by a set of radio communication devices. A comparison of the list with the profile is then sufficient to discard the single-band radio communication devices from the list.

Also, in case the 5 0Hz transmission power level determined at step 510 corresponds to a communication range greater than the 60 0Hz communication range originally defined, another discarding step may also be provided to discard from the list one or more neighboring devices of the obtained list that are beyond the communication range of the 60 0Hz band. The discarding could be based on RTT measurements as introduced below that provide an estimate of the distance between devices.

Starting from the list (possibly reduced with the above discarding step). the neighbor localization module 308 in the reference device initiates and performs triangulation measurements for each neighboring device of the list at step 600.

For example, the triangulation measurement process is as described in the publication Performance evaluation of a TOA-based trilateration method to locate terminals in WLAW' (F. lzquierdo, M. Ciurana, F. Barcelo, J. Paradells and E. Zola, 2006). It is based on round-trip time (RU) measurements between the device to be located and other devices of which the position is already know (e.g. access points in the network), including e.g. the reference multiband radio communication device.

Round-trip time is the time a signal takes to travel from a transmitter to a receiver and back again. In a communication cell based on the 802.11 standard, the RIS and CTS standard messages are generally used to determine such RITs.

Based on the RU estimations, an equation, described in the above publication, makes it possible to convert (i.e. translate) the RU estimations in real distances between the two devices.

Using this method, the reference multiband radio communication device may obtain triangulation measurements from each neighboring device in the list.

Preferably, the reference device performs itself such a Rh-based measurement to deduce a distance with the neighboring device considered in the list. In addition, the same neighboring device transmits other RTT-based measurements (at least two) performed with other devices in the network, the positions of which other devices being known.

Based on the three or more measurements, a triangulation is then performed at step 610 to calculate the coordinates, i.e. to obtain a location, of the neighboring device considered in the list. The obtained location is an approximating geographical location (in the relative or absolute coordinate system introduced above) due to measurement errors.

Preferably, the coordinates (x,y,z) of each neighboring device is calculated in the relative coordinate system, i.e. related to the position of the reference device known as the origin of the axis (0,0,0).

Then at step 620, the measurement errors are modeled to define a search area or volume for the antenna discovery procedure of step 440, which search area or volume is defined in the vicinity of the device location estimated at step 610, preferably centered on that estimated device location, An exemplary modeling is illustrated in Figure 7. Of course, other shapes can be used to provide modeling, such as pyramids.

The modeling of Figure 7 is based on a right circular cone that is coaxial (i.e. aligned) with a straight line between the reference multiband radio communication device and the estimated location of the device considered in the list. Of course, such modeling is performed only for the multiband radio communication devices of the list, since the invention seeks to configure the reference device over the 60 GHz link.

As shown in the Figure, in the relative spherical coordinate system centered onto the reference device i, the estimated location of the device j is defined with at least one elevation angle b (angle between the straight line connecting devices i and j and the straight line x used as the reference line for the antenna angle) and a distance h. To be noted that in the example of the Figure, the azimuth angle is 0 because plane (x,z) is defined to include device j, but azimuth angle is normally considered in addition to elevation angle to define the position of device j.

The right circular cone shown in the Figure to model the measurement errors has an aperture angle 2 * a function of the measurement errors. For example, the semi-aperture a equals to a = cos1 (i_), a being a corrective parameter depending on the measurement errors. For instance a = 0,2 when a maximum of 20% is considered for measurement errors during the estimation of device location.

This modeling shows that the exact position of device j is normally within the sphere centered onto the estimated location and having a radius r (r equals to h.Ja(2 + a) when the above formula for a is used). From the Figure, it may also be understood that, for the reference device i, the exact direction in which device j can normally be reached is within the modeling right circular cone. This is one teaching of the invention to use this modeling right circular cone to restrict the directions that the reference device j will test during a 60 GHZ antenna discovery procedure in view of aligning its directional antenna with device i.

Back to Figure 4, next to step 420, the estimated locations of the devices in the list is provided to the antenna discovery module 309 at step 430. Each estimated location is associated with a model, for example the modeling right circular cone in the

above example.

Next at step 440, the antenna discovery procedure over the 60 GHz band is performed using the model provided for each estimated location to reduce the antenna angular range to be tested.

A standard antenna discovery in the 60 GHz band (for example as specified in the IEEE 802.llad standard) may be used, modified to test only the bundle of directions covered by the reduced antenna angular range, i.e. encompassed by the model.

By reducing the amount of directions to be tested (an angular step may be used to scan the search area in a finite number of possible directions), the antenna discovery according to the invention greatly reduces the time to discover device j and then the exact direction with which the 60 GHz directional antenna should be aligned.

Power consumption for 60 GHz link is therefore also reduced.

Therefore, step 440 results in that the 60 GHz radio module 101 or 111 of the reference multiband radio communication device is ultimately configured with a 60 GHz directional antenna 103 or 113 aligned with the 60 GHz directional antenna of the neighbor multiband radio communication device to which the reference device wants to communicate.

Since the above processes can be performed simultaneously by several multiband radio communication devices in the network (e.g. devices 100 and 110). the invention allows simultaneous point-to-point discovery procedures.

Although the present invention has been described hereinabove with reference to specific embodiments, the present invention is not limited to the specific embodiments, and modifications which lie within the scope of the present invention will be apparent to a person skilled in the art. Many further modifications and variations will suggest themselves to those versed in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only and which are not intended to limit the scope of the invention as determined by the appended claims. In particular different features from different embodiments may be interchanged, where appropriate.

Claims

CLAIMS1. A method of configuring a high-frequency radio module in a multiband radio communication device of a wireless network, comprising: estimating a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over a low-frequency band of the wireless network; performing an antenna discovery procedure over a high-frequency band of the wireless network, to align a directional antenna of the high-frequency radio module with the neighboring multiband radio communication device, wherein the antenna discovery procedure is restricted to an angular range surrounding the estimated location of the neighboring multiband radio communication device.
2. The method of Claim 1, further comprising deriving a level of transmission power to be used during the discovery procedure over the low-frequency band from a communication range defined for the high-frequency band of the wireless network.
3. The method of Claim 1, wherein estimating a location of at least one neighboring multiband radio communication device comprises obtaining a list of neighboring devices from the discovery procedure over the low-frequency band, obtaining triangulation measurements from the discovered neighboring multiband radio communication device, and determining an estimate of location of the neighboring multiband radio communication device from the triangulation measurements.
4. The method of Claim 3, wherein the triangulation measurements are round-trip-time-based measurements between the discovered neighboring multiband radio communication device and three or more other radio communication devices, possibly including one or more single-band radio communication devices.
5. The method of Claim 3, wherein one or more single-band radio communication devices configured to communicate over the low-frequency band are discarded from the obtained list of neighboring devices in order to determine a location of only neighboring multiband radio communication devices.
6. The method of Claim 3, wherein the high-frequency band of the wireless network is short-ranged and the low-frequency band of the wireless network is long-ranged; and one or more neighboring devices of the obtained list that are beyond a communication range of the high-frequency band are discarded from the obtained list.
7. The method of Claim 1, wherein the angular range is defined as the aperture of a right circular cone coaxial with a straight line between the multiband radio communication device and the estimated location of the neighboring multiband radio communication device.
8. The method of Claim 7, wherein the aperture defining the angular range for the antenna discovery procedure does not depend on the distance between the multiband radio communication device and the estimated location of the neighboring multiband radio communication device.
9. The method of Claim 7, wherein the aperture defining the angular range is equal to 2 * a all around the straight line, where a = cos1 (--), a being a corrective parameter.
10. The method of Claim 1, wherein the method is performed at the multiband radio communication device.
11. The method of Claim 1, wherein the discovery procedure over the low-frequency band involves single-band radio communication devices configured to communicate over the low-frequency band.
12. A multiband radio communication device of a wireless network, comprising: a low-frequency radio module; a high-frequency radio module including a directional antenna; a neighbor determination and localization module configured to estimate a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over a low-frequency band of the an antenna discovery module configured to perform an antenna discovery procedure aver a high-frequency band of the wireless network, to align the directional antenna of the high-frequency radio module with the neighboring multiband radio communication device, wherein the antenna discovery module is further configured to restrict the antenna discovery procedure to an angular range surrounding the estimated location of the neighboring multiband radio communication device.
13. The multiband radio communication device of Claim 12, further comprising a low-frequency transmission power determining module configured to derive a level of transmission power to be used during the discovery procedure over the low4requency band from a communication range defined for the high-frequency band of the wireless network.
14. The multiband radio communication device of Claim 12, wherein the neighbor determination and localization module is configured to obtain a list of neighboring devices from the discovery procedure over the low-frequency band, to obtain triangulation measurements from the discovered neighboring multiband radio communication device, and to determine an estimate of location of the neighboring multiband radio communication device from the triangulation measurements.
15. The multiband radio communication device of Claim 14, wherein the triangulation measurements are round-trip-time-based measurements between the discovered neighboring multiband radio communication device and three or more other radio communication devices, possibly including one or more single-band radio communication devices.
16. The multiband radio communication device of Claim 14, configured to discard one or more single-band radio communication devices configured to communicate over the low-frequency band, from the obtained list of neighboring devices, in order to determine a location of only neighboring multiband radio communication devices.
17. The multiband radio communication device of Claim 14, wherein the high-frequency band of the wireless network is short-ranged and the low-frequency band of the wireless network is long-ranged; and the multiband radio communication device is configured to discard one or more neighboring devices of the obtained list that are beyond a communication range of the high-frequency band, from the obtained list.
18. The multiband radio communication device of Claim 12, wherein the angular range is defined as the aperture of a right circular cone coaxial with a straight line between the multiband radio communication device and the estimated location of the neighboring multiband radio communication device.
19. The multiband radio communication device of Claim 18, wherein the aperture defining the angular range for the antenna discovery procedure does not depend on the distance between the muttiband radio communication device and the estimated location of the neighboring multiband radio communication device.
20. The multiband radio communication device of Claim 18, wherein the aperture defining the angular range is equal to 2 * a all around the straight line, where a = cos1 (-k--), a being a corrective parameter.
21. The multiband radio communication device of Claim 12, wherein the discovery procedure over the low-frequency band involves single-band radio communication devices configured to communicate over the low-frequency band.
22. A wireless communication system comprising a plurality of multiband radio communication devices, each according to Claim 12.
23. A non-transitory computer-readable medium storing a program which, when executed by a microprocessor or computer system in a rnultiband wireless communication device of a wireless network, causes the device to perform the steps of: estimating a location of at least one neighboring multiband radio communication device in the wireless network, using a discovery procedure over a low-frequency band of the wireless network; performing an antenna discovery procedure over a high-frequency band of the wireless network, to align a directional antenna in a high-frequency radio module of the multiband wireless communication device with the neighboring multiband radio communication device, wherein the antenna discovery procedure is restricted to an angular range surrounding the estimated location of the neighboring multiband radio communication device.
24. A method of configuring a high-frequency radio module in a multiband radio communication device of a wireless network substantially as herein described with reference to, and as shown in, Figure 4; Figures 4 and 5; Figures 4, 5 and 6; and Figures 4, 5, 6 and 7 of the accompanying drawings.
25. A multiband radio communication device of a wireless network substantially as herein described with reference to, and as shown in, Figure 3 of the accompanying drawings.
26. A wireless communication system substantially as herein described with reference to, and as shown in, Figures 1 and 3 of the accompanying drawings.