US20130016660A1 - Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse - Google Patents

Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse Download PDF

Info

Publication number
US20130016660A1
US20130016660A1 US13/550,177 US201213550177A US2013016660A1 US 20130016660 A1 US20130016660 A1 US 20130016660A1 US 201213550177 A US201213550177 A US 201213550177A US 2013016660 A1 US2013016660 A1 US 2013016660A1
Authority
US
United States
Prior art keywords
base stations
terminals
plurality
method
apparatus
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/550,177
Inventor
Rehan Jalil
Mustafa Ergen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WiChorus Inc
Original Assignee
WiChorus Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US75345205P priority Critical
Priority to US11/644,136 priority patent/US7738875B2/en
Priority to US12/772,929 priority patent/US8224340B2/en
Application filed by WiChorus Inc filed Critical WiChorus Inc
Priority to US13/550,177 priority patent/US20130016660A1/en
Publication of US20130016660A1 publication Critical patent/US20130016660A1/en
Application status is Abandoned legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W64/00Locating users or terminals or network equipment for network management purposes, e.g. mobility management
    • H04W64/003Locating users or terminals or network equipment for network management purposes, e.g. mobility management locating network equipment

Abstract

Method for estimating position information of base stations as well as terminals for three dimensional centralized real-time spectrum management to achieve high spectral efficiency. In one aspect of the invention, the method comprises i) understanding the position information of plurality of base stations, wherein the plurality of terminals and the base stations form a wireless network, ii) determining, at the central controller, position of a terminal via plurality of communication wirelessly between the base stations and a terminal and between the base station and the central controller, iii) applying network wide real time knowledge at the central controller to electronically steerable antennas to use a resource in a different direction then where it is used by other base stations to achieve frequency reuse of one.

Description

    STATEMENT OF RELATED APPLICATIONS
  • This application is a continuation of U.S. patent application Ser. No. 12/772,929, entitled “Method and Apparatus to Estimate Relative Base Station and Subscriber Terminal Locations and Using it to Increase Frequency Reuse” filed in the United States Patent and Trademark Office on May 3, 2010, which is a continuation of U.S. patent application Ser. No. 11/644,136, now U.S. Pat. No. 7,738,875, entitled “Method and Apparatus to Estimate Relative Base Station and Subscriber Terminal Locations and Using it to Increase Frequency Reuse”, filed in the United States Patent and Trademark Office on Dec. 22, 2006, which claims the benefit to U.S. Provisional Application No. 60/753,452, filed in the United States Patent and Trademark Office on Dec. 22, 2005. The teachings of all patents, published applications, and references cited herein are incorporated by reference in their entirety herein.
  • SUMMARY OF THE INVENTION
  • In this invention, a method is proposed to find relative location of fixed base stations in the network; only distance information between some subscriber terminals and base stations are known if it is within the range. One part of the embodiment proposes a method to localize base stations. The method localizes base stations by selecting a base station as an origin of a local coordinate, and estimating possible positions of the base stations based on distance estimates reported by the terminals. Another embodiment of this invention proposes a method to locate terminals along with base stations. Final embodiment of this invention proposes a scheduling method in an OFDMA/TDMA/FDMA network in which there is a single channel which is used by all base stations. The scheduling method implements a scheduler in the base station to electronically steer the antennas of the base stations. Method achieves frequency reuse close to 1 by using a resource in a direction that does not conflict with others by the help of electronically steerable antennas and position information of the base stations and terminals. Further, the scheduler schedules a resource with respect to terminals bandwidth and informs other base stations not to schedule any resource in a contending direction. Furthermore, the scheduling method synchronizes all the base stations to transmit and receive frames in the same time and same frequency, whereby each of the base stations is aware of the scheduling in a neighboring base station in a way to reduce interference.
  • In another aspect, an apparatus for estimating a relative position of a base station and a terminal in a wireless network and using the relative position information to increase frequency reuse is disclosed. The apparatus includes a central controller, a plurality of terminals, at least three base stations, and the central controller is communicatively coupled with each terminal and base station in the wireless network using an OFDMA protocol. The terminals on entry into the wireless network estimate distance information by transmitting digital signals to the base stations using timing signals or power dissipation. Further, the central controller processes relative location information of base stations and terminals based on distance information transmitted by the terminals. Furthermore, the central controller includes means for coordinating a scheduler to increase the frequency of reuse by the base station and the terminals with electronically steerable antenna.
  • The method and system proposed in this invention can be generalized to three dimensional space in which base stations and terminals are placed in 3-D space.
  • BRIEF DESCRIPTION OF DRAWINGS
  • The objective of the present invention will be more apparent from the following detailed drawings, in which:
  • FIG. 1 illustrates the network diagram where there are mobile stations, base stations a central controller connected to IP backbone.
  • FIG. 2 depicts a scanning procedure where each mobile station range with a BS and estimate the distance from the ranging parameters.
  • FIG. 3 shows the diagram of the method.
  • FIG. 4 shows the BS locationing with full distance information from MS.
  • FIG. 5 illustrates a network deployment with three base stations and 19 terminals.
  • FIG. 6 illustrates a build-up mechanism to construct a map from partial information.
  • FIG. 7 illustrates the mechanism to locate the mobile stations.
  • FIG. 8 illustrates the shadow point if there are only two distance estimates.
  • FIG. 9 illustrates the coordination of the central controller to provide location based scheduling with steerable antennas to increase the frequency reuse.
  • INTRODUCTION TO CERTAIN INVENTIVE PARTS OF INVENTION
  • We consider a wireless network where there are plurality of terminals (Ts) and plurality of base stations (BSs) and central controller as seen in FIG. 1. Terminals can be mobile or fixed but base stations are fixed. We also consider a central controller that can do command control to BSs. A terminal in order to associate with a BS can scan multiple BSs at a given time without initiating an association in a typical network shown below.
  • A T first scans for the BS in the network entry procedure. In the scanning procedure the T can estimate its distance to a BS. As a result, after the network entry procedure a T has a set of distance estimates for the BSs that are in the vicinity of its range. Distance estimates can be done in various ways including RSSI based estimation, time of flight based estimation. FIG. 2 illustrates the network for scanning. This scanning report is sent to the central controller.
  • Based on the collected measurements, the central controller can construct the matrix (C) in Table I. Useful information in C is D matrix. One can see that there is no mechanism to estimate the distances between BSs and the distances between Ts and some distance estimates are censored between Ts and BSs because of the range limitations.
  • Methodology for the Invention
  • For simplicity, we describe two-dimensional localization. However, our algorithm extends straightforwardly to three dimensions. We define a cluster as a set of four or more BSs, and a set of Ts such each Ts is connected to at least two of these BSs. A Ts is connected to a BS when it is in its communication range.
  • The algorithm can be broken down into three main phases. The first phase localizes the elements of clusters, BSs and Ts, into a local coordinate system. The second phase finds the relative positions among clusters and computes coordinate transformations between each cluster's local coordinate systems and generates a unique global coordinate system. The third phase refines the localization of the clusters using the periodical updates sent by the Ts. An example is depicted in FIG. 3.
  • The three phases of the algorithm are as follows:
  • Phase I. Cluster Localization: A BS becomes the origin of the local coordinate system of a cluster and the algorithm estimates the relative location of the neighboring BSs which can be unambiguously localized. We call this process cluster localization. For each cluster, we identify the sets of possible positions of the BSs given the distance estimates, reported by the Ts. The Ts and BSs's positions are jointly estimated. The figure below exemplifies the cluster localization for three base stations and five terminals.
  • Phase II. Cluster Transformation. The algorithm finds the set of BSs in common between two clusters. In the next step, the remaining BSs belonging to the two clusters are localized relative to the known positions using trilateration. Finally, the algorithm computes transformations between the local coordinate systems of neighboring clusters.
  • Phase III. Cluster Optimization. Refine the position estimates for each cluster using the periodical updates sent by Ts. This phase reduces and any accumulated error that results from the incremental approach used in the second phase.
  • Cluster Localization
  • The goal of cluster localization is to compute the position of a cluster of BSs and Ts in a local coordinate system up to a global rotation and possible reflection. The algorithm provides that the relative positions of the nodes in a cluster are unique up to a global rotation, translation, and reflection. Using this property any two clusters sharing three BSs form a larger cluster that is also globally rigid. By induction, any number of clusters chained in this manner forms a globally rigid graph.
  • The algorithm for Phase 1, cluster localization, is as follows:
  • 1. The central controller identifies a cluster of nc (nc>4) BSs. Given D, all the distance estimates dij involving to BSs in the cluster are selected. Let mc (<m) be the number of Ts connected to the mc BSs. This corresponds to performing rows and columns operations on D in order to find all the submatrices Dc of dimension mc×nc whose elements are not all different form zero. For simplicity, Ts with only one connectivity are neglected.
  • 2. We define a relative coordinate system for the cluster, where BS1 is at the origin and MS1 is arbitrarily placed at location (Dcl 1,0).
  • 3.Localizing BSs in clusters: the relative positions of the BSs in each cluster are estimated using uniquely the distance estimates in Dc. Algorithm 1 accomplishes this task. We define estMSj as the set of possible locations for MSj, j=1, 2, . . . , mc that are consistent with Dc. Similarly, define estBSl as the set of possible locations for BSl, i=1, 2, . . . , nc that are consistent with Dc. Algorithm 1 proceeds by progressively excluding from these sets points that are not consistent with the matrix Dc.
  • ALGORITHM 1
  • Localization within a cluster
    • set estBSl=[0,0] and
    • estMS1=[Dcl1,0];
    • for all MSj, j=2, . . . mc
      • If Dcj0 not ‘full’
      • estMSj=circle ([0,0], Dcj0) j=2, . . . , mc
      • estBSl=circle ([Dc11, 0], Dc11) i=2, . . . , nc
    • for all BS1
      • delete (x,y) in estBSl inside circle ([0,0], mindistBS)
      • for all MSj such that Dcjl and Dcji not ‘null’ delete (x,y) in estBSl outside circle ([0,0], Dcjl+Dcji)
        while localization is complete
      • for all BS j
      • for all MS i
      • delete points in estBSj and estMSi not consistent with Dc
  • When the connectivity is high enough, the relative positions of the BSs are unique up to a global rotation, translation and reflection.
  • FIG. 4 shows an example of cluster with four BSs and twenty MSs. The dotted lines show the connections between BSs and MSs. FIG. 5 shows the output of Algorithm 1 when applied to this cluster. For simplicity, the relative location, of the BSs are rotated and translated such that the algorithm's output can be compared with the original network.
  • Cluster Transformation
  • In Phase II, the algorithm localizes the relative positions among clusters by chaining together clusters as seen in FIG. 6. Whenever two clusters have three nodes in common, it is possible to localize the clusters relative to each other. If the first cluster is fully localized, we can localize the second cluster by trilaterating from the three known positions. The global network can be thought as a graph of clusters, and localization amounts to trilaterating overlapping graphs. This operation can be performed in linear-time.
  • Cluster Optimization
  • Distance updates periodically sent by Ts can be used to improve the localization performance of the previous two phases. As time goes on, the distance estimates for each graph increase. The central controller can store all the updates in a database, and Phase I and Phase II can be periodically re-computed with the updated information. Since the base station locations are fixed the computed output shall be fed as an input to do fine tuning.
  • Terminal Localization
  • Once the base station locations are fixed, then terminal's position can be found by triangulation. Terminals that have at least three estimates have enough information to find the location. FIG. 7 shows the examples of triangulation.
  • However, for terminal 2 in FIG. 7, there could be a shadow point as seen in FIG. 8. Location A and B cannot be differentiated by distance estimates but wireless signal conditions in a given area can be used to differentiate those two locations, also possibility of having those shadow points diminishes with the dense deployment of base stations. Mobility pattern of the terminal also brings side information to identify its location.
  • Frequency Reuse With Steerable Antenna Along With Locationing
  • In OFDMA/TDMA network, interference region between base stations can be avoidable by defining non-overlapping regions inside the given resource. A resource is considered as a collection of slots which are mapped into frequency and symbol axis. Non-overlapping regions can be constructed in the central controller via global knowledge of the topology to be assigned to different base stations which are sharing a terminal which is in the interference region of theirs. In this way, same resource can be used across the network by all base stations but they do use or blank out some regions according to the occupancy in their interference regions. In this way frequency reuse is close to unity.
  • When an electronically steerable antenna is available along with the locationing information of each terminal, frequency reuse of unity is achieved via single channel across network by directing non-overlapping resources to different terminals. If there is a conflicting node which is in the vicinity of BS1 and BS2. If BS1 uses a resource for that conflicting node, BS2 is allowed to use that resource only in a location different than the location of that conflicting node consequently which guarantees no interference with BS1's transmission. As a result, all resources are put to use but they are used with respect to geographical location of terminals.
  • An example is shown in FIG. 9 where there are two base stations; Base station 1 assigns resource R 1 to terminal 1 and base station 2 uses R 1 in different direction which is guaranteed to be
  • The description presented above only includes some but not all embodiments of the invention. Related other ways of managing three dimensional spectrum management to achieve high spectral efficiency may be devised without departing from the original scope of this invention, and are thus include by the present invention.

Claims (21)

1. A method for increasing access to a wireless network, the method comprising:
determining relative locations of the plurality of terminals with respect to the base stations; and
electronically steering respective antennas based on the determined relative locations to increase frequency reuse in the wireless network.
2. The method of claim 1, wherein determining relative locations of the plurality of terminals with respect to the base stations includes:
scanning a plurality of terminals on entry of the plurality of terminals into the wireless network by transmitting digital signals to the plurality of terminals;
estimating respective distances from the plurality of terminals to each of the base stations using the transmitted digital signals.
3. The method of claim 2, further comprising
transmitting distance information including the estimated distances to each of the base stations; and
storing and processing the distance information.
4. The method of claim 1, wherein determining relative locations of the plurality of terminals with respect to the base stations includes cluster localizing, cluster transforming, and cluster optimizing.
5. The method of claim 4, wherein the cluster localizing includes selecting a base station of the base stations as an origin of a local coordinate, and estimating possible positions of the plurality of terminals based on the estimated distances.
6. The method of claim 4, further comprising using a smart scheduling at the base stations to increase frequency reuse.
7. The method of claim 4, wherein a scheduler schedules a resource with respect to terminals bandwidth.
8. The method of claim 7, wherein the base stations are synchronized to transmit and receive frames in the same time and same frequency, whereby the other base stations are aware of the scheduling in a neighboring base station in a way to reduce interference.
9. The method of claim 7, wherein the base stations are synchronized to transmit and receive frames in different time and same frequency, whereby the other base stations are aware of the scheduling in a neighboring base station in a way to reduce interference.
10. The method of claim 7, wherein the base stations are synchronized to transmit and receive frames in same time and different frequency, whereby the other base stations are aware of the scheduling in a neighboring base station in a way to reduce interference.
11. The method of claim 4 further comprising constructing and refining non-overlapping regions and interference regions for each of the base stations and the plurality of terminals based on the periodically determined relative locations of the plurality of terminals and the base stations.
12. The method of claim 11 further comprising scheduling a resource of a base station of the base stations based on the constructed and refined non-overlapping regions and interference regions.
13. An apparatus for increasing access to a wireless network, the apparatus comprising:
a determination module configured to determine relative locations of a plurality of terminals with respect to the base stations; and
a steering module configured to steer antennas electronically based on the determined relative locations to increase frequency reuse.
14. The apparatus of claim 13 further comprising:
a scanning module configured to scan a plurality of terminals on entry of the plurality of terminals into the wireless network by ways of transmitting digital signals to the plurality of terminals.
15. The apparatus of claim 14 further comprising an estimation module configured to estimate respective distances from the plurality of terminals using the transmitted digital signals.
16. The apparatus of claim 15 further comprising:
a transmission module configured to transmit distance information including the periodically estimated distances to each of the base stations; and
a memory configured to store the distance information and process the distance information.
17. The apparatus of claim 13, wherein the determining module is further configured to determine relative locations of the plurality of terminals with respect to the base stations by performing: cluster localizing, cluster transforming, and cluster optimizing.
18. The apparatus of claim 17, further comprising a processor configured to instruct a scheduler to schedule a resource to increase frequency reuse.
19. The apparatus of claim 17, further comprising a processor configured to construct and refine non-overlapping regions and interference regions for each of the base stations and the plurality of terminals based on the determined relative locations of the plurality of terminals and the base stations.
20. The apparatus of claim 19, wherein the processor is further configured to instruct the scheduler to schedule a resource based on the constructed and refined non-overlapping regions and interference regions.
21. A computer program product having a non-transitory computer readable medium with computer readable instructions stored thereon for increasing access to a wireless network, the computer readable program, when executed by a processor, causes the processor to:
determine relative locations of the plurality of terminals with respect to the base stations; and
electronically steer respective antennas based on the determined relative locations to increase frequency reuse in the wireless network.
US13/550,177 2005-12-22 2012-07-16 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse Abandoned US20130016660A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US75345205P true 2005-12-22 2005-12-22
US11/644,136 US7738875B2 (en) 2005-12-22 2006-12-22 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse
US12/772,929 US8224340B2 (en) 2005-12-22 2010-05-03 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse
US13/550,177 US20130016660A1 (en) 2005-12-22 2012-07-16 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US13/550,177 US20130016660A1 (en) 2005-12-22 2012-07-16 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US12/772,929 Continuation US8224340B2 (en) 2005-12-22 2010-05-03 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse

Publications (1)

Publication Number Publication Date
US20130016660A1 true US20130016660A1 (en) 2013-01-17

Family

ID=40508971

Family Applications (4)

Application Number Title Priority Date Filing Date
US11/644,136 Active 2028-10-30 US7738875B2 (en) 2005-12-22 2006-12-22 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse
US12/772,929 Active US8224340B2 (en) 2005-12-22 2010-05-03 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse
US13/407,188 Abandoned US20120220304A1 (en) 2005-12-22 2012-02-28 Method and Apparatus To Estimate Relative Base Station and Subscriber Terminal Locations and Using It To Increase Frequency Reuse
US13/550,177 Abandoned US20130016660A1 (en) 2005-12-22 2012-07-16 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse

Family Applications Before (3)

Application Number Title Priority Date Filing Date
US11/644,136 Active 2028-10-30 US7738875B2 (en) 2005-12-22 2006-12-22 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse
US12/772,929 Active US8224340B2 (en) 2005-12-22 2010-05-03 Method and apparatus to estimate relative base station and subscriber terminal locations and using it to increase frequency reuse
US13/407,188 Abandoned US20120220304A1 (en) 2005-12-22 2012-02-28 Method and Apparatus To Estimate Relative Base Station and Subscriber Terminal Locations and Using It To Increase Frequency Reuse

Country Status (1)

Country Link
US (4) US7738875B2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014149814A1 (en) * 2013-03-15 2014-09-25 Vivint, Inc. Bandwidth estimation based on location in a wireless network
US20140334463A1 (en) * 2012-07-09 2014-11-13 Justin Lipman Trilateration processing
US20170351831A1 (en) * 2016-06-01 2017-12-07 International Business Machines Corporation Personal travel health vulnerability navigator

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9220129B2 (en) * 2009-06-15 2015-12-22 Nokia Solutions And Networks Oy Communication method and system
US8712432B2 (en) 2010-07-01 2014-04-29 Absolute Software Corporation Method and system for tracking mobile electronic devices while conserving cellular network resources
US8958835B2 (en) * 2011-03-07 2015-02-17 Telefonaktiebolaget L M Ericsson (Publ) Wireless device position determining and frequency assigning systems, devices and methods
US9749810B1 (en) 2016-02-23 2017-08-29 At&T Mobility Ii Llc User equipment assisted indoor small cell location determination

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5303240A (en) * 1991-07-08 1994-04-12 Motorola, Inc. Telecommunications system using directional antennas
US5410588A (en) * 1991-04-03 1995-04-25 Kabushiki Kaisha Toshiba Mobile radio communications system having a supervising radio transmitting station for transmitting a reference synchronizing signal to a first and second base stations via a radio link
US20010012278A1 (en) * 2000-02-03 2001-08-09 Ching-Wen Ma Non-SDMA system with an SDMA method
US20020021684A1 (en) * 2000-04-21 2002-02-21 Kabushiki Kaisha Toshiba Radio base station and frame configuration method using TDMA scheme and SDMA scheme
US20020086691A1 (en) * 2001-01-03 2002-07-04 Zoran Kostic Combined simulcasting and dedicated services in a wireless communication system
US20030119559A1 (en) * 2001-11-29 2003-06-26 Interdigital Technology Corporation System and method utilizing dynamic beam forming for wireless communication signals
US20030190920A1 (en) * 2002-03-27 2003-10-09 Lg Electronics Inc. Location tracing system for mobile telecommunication terminal and method thereof
US20030214914A1 (en) * 2002-01-10 2003-11-20 Harris Corporation Wireless communication network including directional and omni-directional communication links and related methods
US20040198381A1 (en) * 2002-10-08 2004-10-07 Siegel Neil G. Finding cell phones in rubble and related situations
US20070037584A1 (en) * 2005-08-09 2007-02-15 Lg Electronics Inc. Method for triggering handover of mobile terminal and system thereof
US20090116444A1 (en) * 2008-07-22 2009-05-07 Mediatek Inc. Method for achieving frequency reuse in wireless communications systems

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5239673A (en) * 1990-10-29 1993-08-24 International Business Machines Corporation Scheduling methods for efficient frequency reuse in a multi-cell wireless network served by a wired local area network
DK0752113T3 (en) * 1994-03-25 2002-02-25 Qualcomm Inc Method of positioning for use with analogue cellular system
US6396457B1 (en) * 2000-02-29 2002-05-28 Texas Instruments Incorporated Concentrator for coupling local wireless networks to a wired network
US6553234B1 (en) * 2000-05-01 2003-04-22 Alcatel Canada, Inc. Method of frequency reuse in a fixed access wireless network
US7162273B1 (en) * 2000-11-10 2007-01-09 Airgain, Inc. Dynamically optimized smart antenna system
US7260079B1 (en) * 2003-04-07 2007-08-21 Nortel Networks, Ltd. Method and apparatus for directional transmission of high bandwidth traffic on a wireless network
US7269387B2 (en) * 2004-05-28 2007-09-11 Lucent Technologies Inc. Method and apparatus for determining a distance between a base station and a mobile unit
US7751833B2 (en) * 2005-03-15 2010-07-06 Nextel Communications Inc. System and method for determining a base transceiver station location

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5410588A (en) * 1991-04-03 1995-04-25 Kabushiki Kaisha Toshiba Mobile radio communications system having a supervising radio transmitting station for transmitting a reference synchronizing signal to a first and second base stations via a radio link
US5303240A (en) * 1991-07-08 1994-04-12 Motorola, Inc. Telecommunications system using directional antennas
US20010012278A1 (en) * 2000-02-03 2001-08-09 Ching-Wen Ma Non-SDMA system with an SDMA method
US20020021684A1 (en) * 2000-04-21 2002-02-21 Kabushiki Kaisha Toshiba Radio base station and frame configuration method using TDMA scheme and SDMA scheme
US20020086691A1 (en) * 2001-01-03 2002-07-04 Zoran Kostic Combined simulcasting and dedicated services in a wireless communication system
US20030119559A1 (en) * 2001-11-29 2003-06-26 Interdigital Technology Corporation System and method utilizing dynamic beam forming for wireless communication signals
US20030214914A1 (en) * 2002-01-10 2003-11-20 Harris Corporation Wireless communication network including directional and omni-directional communication links and related methods
US20030190920A1 (en) * 2002-03-27 2003-10-09 Lg Electronics Inc. Location tracing system for mobile telecommunication terminal and method thereof
US20040198381A1 (en) * 2002-10-08 2004-10-07 Siegel Neil G. Finding cell phones in rubble and related situations
US20070037584A1 (en) * 2005-08-09 2007-02-15 Lg Electronics Inc. Method for triggering handover of mobile terminal and system thereof
US20090116444A1 (en) * 2008-07-22 2009-05-07 Mediatek Inc. Method for achieving frequency reuse in wireless communications systems

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140334463A1 (en) * 2012-07-09 2014-11-13 Justin Lipman Trilateration processing
US9119040B2 (en) * 2012-07-09 2015-08-25 Intel Corporation Trilateration processing
WO2014149814A1 (en) * 2013-03-15 2014-09-25 Vivint, Inc. Bandwidth estimation based on location in a wireless network
US9788220B2 (en) 2013-03-15 2017-10-10 Vivint, Inc. Bandwidth estimation based on location in a wireless network
US10200899B2 (en) 2013-03-15 2019-02-05 Vivint, Inc. Bandwidth estimation based on location in a wireless network
US20170351831A1 (en) * 2016-06-01 2017-12-07 International Business Machines Corporation Personal travel health vulnerability navigator

Also Published As

Publication number Publication date
US20120220304A1 (en) 2012-08-30
US20090088167A1 (en) 2009-04-02
US20100216463A1 (en) 2010-08-26
US7738875B2 (en) 2010-06-15
US8224340B2 (en) 2012-07-17

Similar Documents

Publication Publication Date Title
JP5558241B2 (en) Method and apparatus for estimating position of radio station using multi-beam
CN105637917B (en) The division and distribution of PCI for cellular network
EP1608110B1 (en) Method for radio communication and radio communication system with radio relay stations in a zig-zag-arrangement
CN101632322B (en) Subscriptionless location of wireless devices
CN101990289B (en) Power distribution method, communicator and program
KR101672073B1 (en) Method, apparatus and system for defining positioning configuration in a wireless network
US6700535B2 (en) Location estimation in narrow bandwidth wireless communication systems
US7627327B2 (en) Network overlay location system and method for air interface with frequency hopping
US5870385A (en) Allocation method and apparatus for reusing network resources in a wireless communication system
CN101998530B (en) Communication control method, communication device, and program
DE69233707T2 (en) Cordless communication system with multiple access through space multiplexing
KR20100017120A (en) Sparsed u-tdoa wireless location networks
US8249033B2 (en) Communication between overlapping WRAN cells working in different channels
JP2017096970A (en) Multi-path mitigation in rangefinding and tracking of objects using reduced attenuation rf technology
US20050202784A1 (en) Method and system for reducing wireless multi-cell interferences through segregated channel assignments and segregated antenna beams
JP2006501778A (en) Location-based method and system for wireless mobile unit communication
ES2328992T3 (en) Synchronization procedure of a base station network.
DE60316975T2 (en) Method for finding a mobile station and a interim amplifier of the mobile station
TWI493994B (en) Systems and methods for location positioning within radio access systems
KR101108416B1 (en) Pilot signals for use in multi-sector cells
US20060258362A1 (en) Method and system for reducing wireless multi-cell interferences through segregated channel assignments and segregated antenna beams
EP1380851B1 (en) Position calculation method of a mobile terminal
US6771966B1 (en) System and method for an automated radio network planning tool
JP2007506376A (en) Wireless LAN planning facilitated by simulation
US20040157613A1 (en) Self-selection of radio frequency channels to reduce co-channel and adjacent channel interference in a wireless distributed network

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION