WO2002080597A1 - Procede de determination de la topologie de stations de base dans un reseau sans fil - Google Patents

Procede de determination de la topologie de stations de base dans un reseau sans fil Download PDF

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Publication number
WO2002080597A1
WO2002080597A1 PCT/AU2002/000381 AU0200381W WO02080597A1 WO 2002080597 A1 WO2002080597 A1 WO 2002080597A1 AU 0200381 W AU0200381 W AU 0200381W WO 02080597 A1 WO02080597 A1 WO 02080597A1
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WIPO (PCT)
Prior art keywords
network
base station
fixed terminals
positions
bluetooth
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PCT/AU2002/000381
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English (en)
Inventor
Paul Ostergaard
Dickson Poon
Stephen Hill
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Norwood Systems Pty Ltd
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Publication date
Application filed by Norwood Systems Pty Ltd filed Critical Norwood Systems Pty Ltd
Publication of WO2002080597A1 publication Critical patent/WO2002080597A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/18—Network planning tools
    • H04W16/20—Network planning tools for indoor coverage or short range network deployment
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/0284—Relative positioning
    • G01S5/0289—Relative positioning of multiple transceivers, e.g. in ad hoc networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
    • H04L41/12—Discovery or management of network topologies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
    • H04W84/22—Self-organising networks, e.g. ad-hoc networks or sensor networks with access to wired networks

Definitions

  • the present invention relates to a method for determining base station topology in a wireless network particularly, although not exclusively, between wireless Bluetooth TM devices, in a Pico-cellular network, such as a Personal Area Network.
  • PDAs personal digital assistants
  • headsets have traditionally been connected together by cables.
  • the major shortcomings of this approach include the number of cables to be carried around and the difficulties of getting compatible connections between devices from different vendors.
  • PAN Personal Area Network
  • the PAN provides a useful solution for an individual and his personal devices.
  • a logical extension to this model is for one member of the PAN to be a laptop or PC that is connected to a corporate Local Area Network (LAN). Extending this concept to an office environment leads to the conclusion that there will be many PANs in an office; in the extreme each office worker will have an individual PAN with a LAN connection.
  • LAN Local Area Network
  • meta-PAN Such a managed group of PANs is described as a "meta-PAN”.
  • a meta-PAN allows the individual personal productivity devices to be integrated into the enterprise information systems. This integration is achieved by applying policies to manage, for example, radio interference between PANs, security and access control of devices, coverage, capacity and connectivity to central services.
  • Bluetooth One such wireless standard that has been developed is the Bluetooth TM standard developed by a consortium of parties and intended to achieve interoperability between different wireless devices - even if produced by different manufacturers. Bluetooth is know to persons skilled in the art and therefore need not be described in full detail herein. For further details, the addressee is directed to the Bluetooth Specifications provided by the Bluetooth Special Interest Group.
  • Bluetooth devices are radio-based devices, and are designed to operate within PANs of, typically, cell radii ranging from less than 10m to more than 100m in ideal conditions. The majority of battery-powered devices are likely to operate with a 10-20m cell radius.
  • Bluetooth devices operate in a frequency band of between 2.4 and 2.5 GHz with a transmitting power of between 1 and 100mW.
  • the maximum bit rate at which data is transferred is 1 Mbit/s although this is effectively lower, but has been estimated as being up to 721 kbits/s.
  • a usage model describes a number of user scenarios - such as file transfer, dial-up networking, LAN access, synchronisation, telephone to service provider connection, and the use of a wireless headset acting as a remote audio input/ output device.
  • a profile defines options in each protocol that are mandatory for that profile, as well as parameter ranges for each protocol.
  • Bluetooth profiles There are a number of Bluetooth profiles, and these are set out in the Bluetooth Specification as laid down by the Bluetooth Special Interest Group. These profiles include Generic Access Profile, (GAP), service Discovery Application Profile, (SDAP), Serial Port Profile, and Generic Object Exchange Profile (GOEP). There are a number of core Bluetooth protocols:
  • Baseband which enables the physical Radio-frequency (RF) link between Bluetooth devices, and controls the Bluetooth devices' synchronisation and frequency hopping sequence (discussed below).
  • RF Radio-frequency
  • SCO Synchronous Connection Oriented
  • ACL Asynchronous Connectionless
  • Host Controller Interface provides an interface for accessing hardware capabilities, a command interface to the Baseband Controller and Link Manager, and contains control and event registers.
  • LMP Link Manager Protocol
  • Logical Link Control and Adaptation Protocol provides connection- oriented and connectionless data services, such as multiplexing, segmentation and reassembly of data packets, as well as "quality of service” information between Bluetooth devices, and mapping groups onto a Piconet.
  • SDP Service Discovery Protocol
  • RFCOMM - is a serial port emulation protocol.
  • Telephony Control (TCS) - defines control signalling for the establishment of speech and data calls between Bluetooth devices.
  • a Bluetooth piconet can include up to eight separate Bluetooth devices. When Bluetooth devices are communicating, one is defined as the "Master” and the rest are defined as “Slaves”. The master unit has a system clock and identity that are central to the operation of the frequency hopping. This is well known to persons skilled in the art, and need not be described in any further details herein.
  • Bluetooth uses a frequency hopping technique to avoid interference between RF transmissions.
  • the frequency band is divided into a number of hop channels; with a different hop channel being used every 625 ⁇ s time slot i.e. at a rate of 1600 hops per second. Every hop channel is a fraction of the total frequency band. The hop from one channel to another is affected in a pseudorandom order.
  • Gaussian shaped binary Frequency Shift Key modulation is used, and full duplex transmission is achieved using time division multiplexing wherein subsequent slots are used for transmission and reception.
  • the baseband protocol is a combination of circuit and packet switching. Data is sent in packets - each packet being sent within one time slot. This is illustrated schematically in Figure 3. Each packet includes a 72-bit access code, then a 54-bit header code, and followed by the data file/ payload of anything from zero to 2745 bits i.e. up to 340 bytes.
  • the access code is based on the identity of the master, and it's system clock.
  • a piconet can include up to eight Bluetooth devices, of which one is the master, and the other are slaves. There is no difference between Bluetooth units in terms of the hardware and software that determines their roles, and, therefore, any Bluetooth device can be a master, and any can be a slave.
  • the device that establishes the piconet is the master, and roles within a piconet can be changed, so that a slave can become a master and vice versa.
  • the master unit controls all traffic in the piconet, and allocates capacity for SCO and polling for ACL links. Every slave unit is address in a specific order and polling scheme. Slave units can only transmit in response to an address from the master in the preceding time slot. If no information is sent to the master in response to being addressed, then a packet including only the access code and header is sent.
  • a Bluetooth device Before joining a piconet, a Bluetooth device is in standby, in which the unit periodically "listens” for paging messages - every 1.28 seconds. These paging messages are transmitted on hop carriers known as “wake-up" carriers.
  • the wake-up sequence is transmitted by the master on the wake-up carriers.
  • the slave listens for 18 slots on the wake-up carrier and compares the incoming signal with the access code derived from its own identity, and, if there is a match, the slave invokes a set-up procedure and enters a Connected Mode.
  • the correct access code and wake-up sequence are calculated using the specific slave's identity and system clock. To keep track of the slaves' system clocks, a paging procedure is defined for the master.
  • a unit can participate in two or more overlaying piconets by applying time multiplexing. To participate on the proper channel, it should use the associated master device address and proper clock offset to obtain the correct phase.
  • a Bluetooth unit can act as a slave in several piconets, but only as a master in a single piconet: since two piconets with the same master are synchronized and use the same hopping sequence, they are one and the same piconet.
  • a group of piconets in which connections exist between different piconets is called a scatternet.
  • Bluetooth devices it is common for some Bluetooth devices to be mobile units, which will move about the network. For example, an individual may take his mobile phone and or PDA with him when he walks down the corridor to attend a meeting in another office. Once in the other office, he may wish to retrieve his emails, which will require that his mobile phone or PDA be able to communicate with local base units - commonly referred to as Base Stations (BS). This is called roaming, and the idea of roaming is well known in the field of cellular radio telecommunications.
  • BS Base Stations
  • Mobile Stations When a mobile unit (commonly referred to as Mobile Stations (MS)) is in communication with a Base Station, and the Mobile Station is actually moving, it may be necessary - because the Mobile Station moves away from the Base Station and the signal between the two becomes too weak to enable acceptable communication - to transfer the communication link from the MS to another Base Station with improved Link Quality. Transferring a Mobile Station from a serving Base Station to a new Base Station is called "Handoff". At present, there is no existing technique for performing handoff over Bluetooth.
  • MS Mobile Stations
  • a method for determining the positions of fixed terminals within a wireless communications network comprising the steps of: capturing Received Signal Strength Information (RSSI) measurements between pairs of fixed terminals, building a symmetric distance matrix from the captured RSSI measurements; determining the relative position of the fixed terminals from the distance matrix, calibrating the relative positions with known absolute positions; and deriving absolute positions for all fixed terminals within the network.
  • RSSI Received Signal Strength Information
  • the method may further include the step of determining a connectivity matrix representing the connectivity of each fixed terminal within the communications network and determine the distance matrix from the connectivity matrix.
  • the relative positions can be derived by applying a Torgerson-SMACOF algorithm.
  • a communications network located within a network environment and comprising a plurality of fixed terminals, the network including control means operable to determine the positions of the fixed terminals within the environment by receiving and storing Received Signal Strength Information (RSSI) measurements between pairs of fixed terminals, building a symmetric distance matrix from the captured RSSI measurements; determining the relative position of the fixed terminals from the distance matrix, calibrating the relative positions with known absolute positions; and deriving absolute positions for all fixed terminals within the network.
  • the control means may be further operable to determine a connectivity matrix representing the connectivity of each fixed terminal within the communications network and determine the distance matrix from the connectivity matrix.
  • the control means may be operable to derive the relative positions by applying a Torgerson-SMACOF algorithm.
  • the control means may include a display for displaying the positions of the fixed terminals thereon.
  • the control means may include database means in which the locations of the fixed terminals are stored.
  • the present invention allows the topology of the network to be easily and dynamically determined without the need for specialist modelling tools. It can be easily and quickly updated to reflect changes. It also allows prediction of the network environment.
  • Figure 1 is a schematic illustration of a network comprising a plurality of wireless units in a small environment.
  • Figure 2 is a schematic illustration of the components of a wireless network
  • Figure 3 is a schematic illustration of the components of a network controller for the network of Figure 2;
  • FIG. 4 is a schematic illustration of the components of Bluetooth base station units used in the present invention.
  • Figure 5 is a diagram illustrating the steps involved in the present invention. Best Mode(s) for Carrying Out the Invention
  • fixed is used in relation to terminals. In the present specification, this term is used to define a terminal that is fixed, at any one time, in relation to the mobile terminals. It should be understood that these fixed terminals are not permanently fixed at any one location and can be moved - indeed may often be moved within a network environment. This term should therefore not be construed in a limiting form.
  • the network 100 includes a number - in this embodiment four - Bluetooth base stations, BS1 , BS2, BS3, BS4, which are located throughout an office environment. Each base station can communicate with other Bluetooth units - including the other base stations - in a known manner. Other Bluetooth units may include, for example mobile phones, and PDA's. When in communication with each other, the units form a piconet as described in the description of the prior art.
  • FIG. 2 illustrates schematically some of the components of the network as relevant to the present invention.
  • Each base station 1 comprises a so-called “dongle” 2 plugged into an interface of a conventional personal computer 3 and coupled to components necessary for operation of the base station.
  • These components are commonly referred to as the "softbase” 10, and are illustrated schematically in Figure 4, which is a schematic stack of the components, with lines indicating appropriate communication between the relevant components.
  • These components include the Bluetooth stack components 11 , a manager 12, an H323 stack (whose function is equivalent to that discussed in relation to the service platform 9 below), an Object Manager proxy which manages system information communication with the service platform 9 (by means of its Object Manager), a Transport Manager manages all communication with the service platform 9 and other softbases.
  • Bluetooth devices as well as other components that - in addition to the components mentioned above, in so far as they are not relevant to the present invention, need not be described in any further detail herein.
  • Other Bluetooth devices such as phones, and PDA's, include similar components, as, from the point of view of their operation as Bluetooth devices are concerned, their operation and components provided for their operation, are the same.
  • the base stations 1 are also coupled together to form a Local Area Network (LAN) along with a telephony gateway 4, which is coupled to a PABX system 5, and ultimately to a Public Switched Telephone Network (PSTN) 6.
  • LAN Local Area Network
  • PSTN Public Switched Telephone Network
  • Each base station 1 communicates with other mobile units/ terminals within its range of operation. In this sense it is a cellular system with analogies to known cellular radio systems such as GSM and CDMA. In this network, the average cell size is 10m in radius, and a maximum of 100m
  • the network also includes a network controller 7.
  • the network controller 7 comprises a number of components, which are illustrated schematically in Figure 2.
  • the controller includes a server 8 and the service platform 9.
  • the components for the service platform 9 are illustrated schematically in Figure 3, which is a protocol stack of the various components.
  • the platform 9 includes an Object Manager, an H.323 Gateway a positioning manager, a handoff manager, a user manager, a PAX, a Registrar, and a B-number, as well as other components.
  • the following components have the following functions:
  • Object Manager manages all system information for base stations, mobile units, other terminals and users.
  • H.323 Gateway - manages call set up and routing, and allows voice data to be transmitted over the IP layer.
  • Positioning Manager monitors base stations' positions, manages coverage and capacity, tracks mobile stations.
  • Handoff Manager manages the handoff process.
  • PAX - manages call set-ups to/ from the PBX/PSTN, and deals with the H.323 Gateway.
  • Registrar - deals with terminal registration and authentication, and keeps track of which base station is serving which mobile unit/ terminal.
  • the means of communication between the various components is illustrated by the lines in Figure 3.
  • the Server Transport Manager manages communication with the softbase 10.
  • Bluetooth devices When two Bluetooth devices are in communication with each other they have established a piconet. As mentioned above, up to eight Bluetooth devices can form a piconet, but, for clarity, the operation of only two devices is described.
  • One Bluetooth device BS1 is a base unit (or base station), while the other is a mobile unit MS1. The communication between the two has been established in the usual way in accordance with the Bluetooth protocols.
  • the base station BS1 is the Master unit
  • the mobile station MS1 is the slave unit.
  • the present invention provides a method and system for dynamically determining the real-time physical radio base station topology. Briefly, the system sends a request to all base stations on the network for RSSI (Radio Signal Strength Indication) management information. After receiving this information from each base station, the system builds a data structure containing the RSSI value between each of the stations within the network. The logical map of all the Bluetooth base stations can then be worked out by applying a series of mathematical algorithms.
  • RSSI Radio Signal Strength Indication
  • the physical topology of all the Bluetooth base stations can be displayed, and can be used to predict the physical structure of the building environment, and to map the physical topology of all the base stations to the physical structure of the building environment.
  • the network exists in a normal office environment.
  • An office has many base stations.
  • a base station belongs to one office only.
  • Each base station has an average cell size of 10m radius.
  • the minimum cell size is 2m radius.
  • the maximum cell size is 100m radius.
  • Each Base Station can transmit to at least three other Base Stations.
  • the network controller 7 is operable to instruct each base station to measure the Received Signal Strength Indication (RSSI) of each of its neighbouring base stations.
  • RSSI is an indication of the signal strength and therefore of the quality of the signal sent between two units that are in communication with each other.
  • the use and measurement of this parameter is known in cellular radio telecommunications systems such as GSM and can be achieved by any suitable known manner.
  • Bluetooth units can adopt either master or slave roles - as discussed in the introduction above - and can therefore - when operating as base stations - communicate with each other. Although provided in the network as base stations, it is important to understand that these units can adopt other roles and, in particular, can alternate between master and slave roles within any scatternet that is set up.
  • each base station Before performing the RSSI measurements, each base station performs a discovery process (for example using a known paging technique) to identify each of its neighbouring base stations.
  • the positioning manager inside the network controller 7 sends a command to each Base Station to perform the RSSI measurements for each of the neighbouring base stations.
  • the value of the RSSI will give an indication of the distance of the base station from its neighbouring base station i.e. the poorer the quality of signal between the two base stations, the larger the distance between them.
  • the positioning manager inside the network controller 7 then builds up a data structure containing the RSSI values between each of the stations within the network.
  • the logical map of the base stations can then be worked out by applying a series of algorithms.
  • the logical map is then stored through the object manager and written to the database on the network controller 7.
  • the first step is to identify which base stations overlap and construct a connectivity matrix (CM) to represent the connectivity of each of the base stations.
  • CM connectivity matrix
  • step 9 If cannot find any NEW base station then go to step 9 otherwise go to step 5
  • step 10 If cannot find any CENTER base station then go to step 10 otherwise go to step 4
  • each of the RSSI values in the Distance Matrix D is converted into meters by using the formulae.
  • L path is the path loss
  • ⁇ free space wavelength @ 2.45GHz (0.1224m) and r is the range (m).
  • Torgeson Algorithms are well known, and allow distances to be converted to a matrix of Cartesian co-ordinates. Because the RSSI measurements are known to contain errors, an error minimisation technique is also applied to the estimated relative positions to provide a "best" estimate of the relative positions. In the embodiment described herein, a Torgeson-SMACOF routine is applied to the matrix to provide the results. As the Torgeson- SMACOF routine requires a full matrix, any base stations that are out of range of each other are assigned a distance well beyond the maximum coverage range.
  • the following parameters need to be input in order to finalise the process and allow for the base station topology to be displayed - for example on a display 13 coupled to the network controller 7.
  • This display 13 shows the base station topology as superimposed on the office layout. Details of these parameters can be input via the network controller - for example, by a system administrator.
  • the following parameters need to be specified:
  • the network controller 7 can then apply rotation, scaling and mirroring of the OC so that it matches with the position of the three known base stations - thus allowing the positions of all the base stations to be displayed.
  • a network topology database is maintained and frequently updated to reflect any changes.
  • the system updates the topology when a base station starts up, shuts down or physically moves its location.
  • the system allows the user to set a timer that defines how often the system repeats the data collection process to display an updated map of the network.
  • the information on the absolute positions of the base stations can then be used to model the office environment in which the network is located.
  • Base station signal emissions are initially estimated as being circular and having a range of 10 meters. Firstly, it is assumed that there are no significant obstacles within the office, and create a record of base stations we believe can transmit to each quadrant. This information is updated whenever a connection within the network fails. By using the absolute position of 3 or more base stations and the coverage structure information within the grid system, the In the event a base station shuts down or is recognized as having moved, that station is deleted from all region records. When a new station is introduced or the moved station has had it's position re-determined, that station is put back in the list of each quadrant we believe it can transmit to. At this stage the positions of significant obstacles, determined at prior iterations, are taken into account to give a more true initial representation of irregular shaped coverage.
  • a view of the overall network topology can quickly be built.
  • the positions of the base stations can be periodically checked using different RSSI signal readings, and, so, positional values become more accurate. These positions can be dynamically displayed on a visual display coupled to the network controller thereby giving feedback as to the current state of the network.
  • a base station only fails to cover an area within its signal strength radius if it is blocked by a significant obstacle. Also if a signal is never recorded for a region over the life of the network then this is probably because the area is inaccessible. Once reliable radio base positions and coverage estimations have been determined, this can be used to predict the office structure.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Un réseau de télécommunications sans fil (100) comprend une pluralité d'unités Bluetooth ™ dont certaines sont fixes et font office d'unités de base (BS1; BS2; BS3; BS4) et d'autres mobiles (MS1; MS2; MS3; MS4). Les unités fixes sont connectées à un réseau local (LAN) ainsi qu'à une passerelle téléphonique (4) un PABX (5) et un RTPC (6). La présente invention concerne également des procédés de détermination de la topologie des unités fixes au sein du réseau.
PCT/AU2002/000381 2001-03-28 2002-03-27 Procede de determination de la topologie de stations de base dans un reseau sans fil WO2002080597A1 (fr)

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AUPR4056A AUPR405601A0 (en) 2001-03-28 2001-03-28 Method for determining base station topology in a wireless network
AUPR4056 2001-03-28

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EP1434357A2 (fr) * 2002-12-26 2004-06-30 Kabushiki Kaisha Toshiba Procédé d'économie d'énergie pour un appareil électronique
EP1631832A1 (fr) * 2003-05-26 2006-03-08 Commonwealth Scientific And Industrial Research Organisation Procede de localisation par radio
WO2007121681A1 (fr) * 2006-04-25 2007-11-01 Huawei Technologies Co., Ltd. Procédé et système de balayage topologique
WO2011107453A1 (fr) * 2010-03-03 2011-09-09 Ip.Access Limited Point d'accès, système de communication et procédé pour estimer la valeur de l'affaiblissement de trajet correspondante
EP2405688A1 (fr) * 2010-07-07 2012-01-11 Thomson Licensing Procédé d'évaluation des emplacements de points d'accès sans fil dans un réseau hybride
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WO2000050919A2 (fr) * 1999-02-25 2000-08-31 Microsoft Corporation Utilisation d'une table derivee de donnees concernant l'intensite de signal pour localiser et pister un utilisateur dans un reseau sans fil

Cited By (21)

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US8280388B2 (en) 2002-10-21 2012-10-02 Hong Kong Applied Science And Technology Research Institute Co., Ltd. Systems and methods for managing wireless communications using link space information
EP1420602A3 (fr) * 2002-10-21 2004-06-30 Hong Kong Applied Science and Technology Research Institute Co. Ltd. Systèmes et procédés de gestion de communications sans fil utilisant l'information d'espace des liaisons
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CN100444675C (zh) * 2002-10-21 2008-12-17 香港应用科技研究院有限公司 利用链路空间信息来管理无线通信的系统和方法
EP1420602A2 (fr) * 2002-10-21 2004-05-19 Hong Kong Applied Science and Technology Research Institute Co. Ltd. Systèmes et procédés de gestion de communications sans fil utilisant l'information d'espace des liaisons
EP1434357A2 (fr) * 2002-12-26 2004-06-30 Kabushiki Kaisha Toshiba Procédé d'économie d'énergie pour un appareil électronique
EP1434357A3 (fr) * 2002-12-26 2005-10-26 Kabushiki Kaisha Toshiba Procédé d'économie d'énergie pour un appareil électronique
EP1631832A1 (fr) * 2003-05-26 2006-03-08 Commonwealth Scientific And Industrial Research Organisation Procede de localisation par radio
EP1631832A4 (fr) * 2003-05-26 2007-01-17 Commw Scient Ind Res Org Procede de localisation par radio
WO2007121681A1 (fr) * 2006-04-25 2007-11-01 Huawei Technologies Co., Ltd. Procédé et système de balayage topologique
WO2011107453A1 (fr) * 2010-03-03 2011-09-09 Ip.Access Limited Point d'accès, système de communication et procédé pour estimer la valeur de l'affaiblissement de trajet correspondante
US9125099B2 (en) 2010-03-03 2015-09-01 Ip.Access Limited Access point, communication system and method for estimating a path loss value therefor
EP2405688A1 (fr) * 2010-07-07 2012-01-11 Thomson Licensing Procédé d'évaluation des emplacements de points d'accès sans fil dans un réseau hybride
WO2012004361A1 (fr) * 2010-07-07 2012-01-12 Thomson Licensing Procédé d'évaluation d'emplacements de points d'accès sans fil dans un réseau hybride
US9137682B2 (en) 2010-07-07 2015-09-15 Thomson Licensing Method for evaluating locations of wireless access points in an hybrid network
WO2012158229A1 (fr) * 2011-05-19 2012-11-22 Qualcomm Incorporated Mesures et collecte d'informations dans un environnement de réseau sans fil
US9037180B2 (en) 2011-05-19 2015-05-19 Qualcomm Incorporated Measurements and information gathering in a wireless network environment
WO2013006922A1 (fr) * 2011-07-14 2013-01-17 Norwood Systems Pty Ltd Procédé, dispositif et système pour déterminer la topologie d'un réseau de communication sans fil
US20150024774A1 (en) * 2011-07-14 2015-01-22 Norwood Systems Pty Ltd. Method, Device and System for Determining Topology of a Wireless Communication Network
EP2732302A4 (fr) * 2011-07-14 2015-03-04 Norwood Systems Pty Ltd Procédé, dispositif et système pour déterminer la topologie d'un réseau de communication sans fil
US9482738B2 (en) 2011-07-14 2016-11-01 Norwood Systems Pty Ltd Method, device and system for determining topology of a wireless communication network

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