CA2336636A1 - Wireless local loops including horizontally polarized antennas - Google Patents
Wireless local loops including horizontally polarized antennas Download PDFInfo
- Publication number
- CA2336636A1 CA2336636A1 CA002336636A CA2336636A CA2336636A1 CA 2336636 A1 CA2336636 A1 CA 2336636A1 CA 002336636 A CA002336636 A CA 002336636A CA 2336636 A CA2336636 A CA 2336636A CA 2336636 A1 CA2336636 A1 CA 2336636A1
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- Canada
- Prior art keywords
- antenna
- rfp
- wfau
- wll
- telephone
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/10—Small scale networks; Flat hierarchical networks
- H04W84/14—WLL [Wireless Local Loop]; RLL [Radio Local Loop]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
- H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
- H01Q1/246—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for base stations
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
- H01Q9/0428—Substantially flat resonant element parallel to ground plane, e.g. patch antenna radiating a circular polarised wave
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18513—Transmission in a satellite or space-based system
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Astronomy & Astrophysics (AREA)
- Aviation & Aerospace Engineering (AREA)
- General Physics & Mathematics (AREA)
- Mobile Radio Communication Systems (AREA)
- Details Of Aerials (AREA)
- Radio Transmission System (AREA)
- Radio Relay Systems (AREA)
Abstract
Wireless local loops include primarily non-vertically polarized antennas.
Preferably, the wireless local loop includes horizontally polarized antennas.
By using primarily non-vertically polarized antennas in the WLL, interference between cellular, satellite and/or other radiotelephone communications systems, which employ predominantly vertically polarized antennas, can be reduced and preferably minimized. Conventional cellular and satellite radiotelephone systems use vertically polarized transmissions due to the vertical nature of the orientation of the mobile antennas on vehicles and/or mobile radiotelephones. However, in a WLL, with its fixed wireless telecommunications, there is no need to use vertically oriented antennas.
Accordingly, to reduce interference, antennas that are primarily non-vertically polarized are used.
Preferably, the wireless local loop includes horizontally polarized antennas.
By using primarily non-vertically polarized antennas in the WLL, interference between cellular, satellite and/or other radiotelephone communications systems, which employ predominantly vertically polarized antennas, can be reduced and preferably minimized. Conventional cellular and satellite radiotelephone systems use vertically polarized transmissions due to the vertical nature of the orientation of the mobile antennas on vehicles and/or mobile radiotelephones. However, in a WLL, with its fixed wireless telecommunications, there is no need to use vertically oriented antennas.
Accordingly, to reduce interference, antennas that are primarily non-vertically polarized are used.
Description
WIRELESS LOCAL LOOPS INCLUDING
HORIZONTALLY POLARIZED ANTENNAS
Field of the Invention This invention relates to telecommunications systems and methods, and more particularly to wireless local loops for telephone communications systems and methods.
Background of the Invention Wireless Local Loops (WLL) are widely used in telecommunications systems.
As is well known to those having skill in the art, a wireless local loop uses a radio to provide a telephone connection to or within a building such as a dwelling. In particular, in a telecommm;iications system, a dwelling is connected to a switching office via a local loop, then through a distribution node and a trunked cable that is connected to the switching; office. Conventionally, the local loop is copper cable buried in the ground or carried on overhead pylons to the dwelling, and the tt-unked cable includes multiple copper pairs. WLL replaces the local loop section with a radio path .rather than a copper cable. Accordingly, WLL replaces the connection from the distribution point to the dwelling with a radio path. All other parts of the network may be left unaffected.
In a WLL, the dist~~ibution point is connected to a radio transmitter, referred to herein as a Radio Fixed Part (RFP), that includes an RFP antenna that is responsive to a switching office to wirelessly transmit telecommunications messages from the switching once and to wirelessly receive teleconununications messages for the switching office via the Rl~P antenna. A Wireless Fixed Access Unit (WFAU) including a WFAU antenna is conventionally mounted on the side of the dwelling and is connected to a telephone using a network interface and customer interface to wirelessly transmit telecommunications messages from the telephone to the RFP
and to wirelessly receive telecommunications messages for the telephone from the RFP
via the WFAU antenna. Accordingly, apart from the WFAU on the side of the 09-06-2000 CA 02.336636 2001-O1-04 .. .. .. .. .. ..
.. .. . .. . . .. . ..
. . . . .. . . .... . ..
... . . .. . . . ..
~ . . . . . .. . . ..
- 7 _ ~ .. .. .. .. .. ..
dwelling, the telephone subscuber need not notice any difference between a wireless local loop and a conventional wired local loop.
WLL is used in many telecommunications systems that do not already have conventional wired local loops. Moreover, for those telecommunications systems that S already have wired local loops, WLL is being used by new operators to provide competition to an existing telephone company.
The design and operata.on of WLL systems are well known to those having skill in the art, and need not be described further herein. See, for example, the textbook entitled "Introduction to Wireless Local Loop" by William Webb, Artech House, 1998; "Low-Tier Wireless Local Loop Radio Systems-Part l:
Introduction", by Yu et al., IEEE Communications Magazine, March 1997, pp. 84-92; and "Low-Tier Wireless .Local Loop Ract'io Systems-Part 2: Comparison of Systems ", by Yu et al., IEEE Communications Magazine, March 1997, pp. 94-98. Also see U.S.
Patents 5,475,735 to Williams et al. entitled "Method ofProviding Wireless Local Loop Operation with Local Mobilil)r~ for a Subscribed Unit' ; x,603,095 to Uola entitled "Radio System and a Subscriber Terminal for a Radio System"; 5,604,789 to L,erman entitled "Method and System for Providing a Digital Wireless Local Loop' ; and Des.
386,186 to Schnetzer et al. entitled "Wireless Local Loop Antenna". The disclosures of these patents and other references are hereby incorporated herein in their entirety by reference.
In general, WLLs do n.ot employ separate radio technologies but rather use an existing radio technology in a~z existing radio frequency band. In fact, as described in the above-cited Webb textbook, at the beginning of 1997, there were some fifteen different types of technologies, and some technologies were supported by more than one manufacturer, resulting in about twenty-five different product offerings.
These technologies include cordless technologies such as the Digital European Cordless Telephone (DECT), PHS which is a Japanese standard for use in the 1895-1918 MHz frequency band, and CT-2, w tech was developed in the United Kingdom as an alternative to analog cordless ihome phones. Cellular technologies rnay also be used, including analog cellular systems, such as Analog Mobile Phone System (AMPS) and the Total Access Communications Systems (TACS), and digital cellular systems including GSM, IS-95 and D-.A.MPS. Other proprietary technologies may also be used.
REPLACEMENT SHEET AMENDED SHEET
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.. .. .. . . .. . ..
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- ~a - . .. .. .. .. .. ..
U.S. Patent No. x,444,762 to Frey et al. entitled Method and Apparatus for Reducing Interference Among Cellular Telephone Signals discloses that a directional antennae on aircraft and on cellular telephone base stations, having a polarity opposite that of potentially interfering »ound system signals, minimize signal strength of air cellular signals received by ground cellular stations. Aircraft directional antennae comprise patch antennae or vertical arrays of loop elements or vertical arrays of virtual loop elements. Additionally, air cellular signals are switched to channels not currently in use by ground cellular systems.
PCT Patent WO 98/33338, to TELEFONAKTIEBOLAGET LM ERICSSON, entitled Methad and Apparatus for Reducing Interference Among Cellular Telephone Signals discusses a robust and. frequency-economic point to multipoint radio access microwave system that combines the use of only two frequency bands and alternating polarizations. Base station antennae feeding adjacent sectors from a common base station site operate at least wi~~:h different ones of two set channels.
Moreover, sectors I5 at adjacent base stations sites (e.g., in adjacent cells) which are aligned with the sectors of the first base station site employ either a different set of channels or differing polarization. The tu~o sets of channels can be two sets of frequencies (e.g., FDMA).
REPLACEMENT SHEET AMENDED SHEET
Since WLL systems are present in the same geographic area as cellular, satellite and/or other wireless communications systems and generally use existing technologies, it may be difficult to avoid interference between the WLL
telecommunications messages and existing cellular, satellite and/or other wireless communications messages. Interference may be reduced somewhat by intelligent frequency allocation of the WLL wireless transmissions. However, this frequency allocation may be difficult to perform in view of the many other wireless radiotelephone communications systems that already may be present. Moreover, the frequency allocation may nE:ed to be updated as additional cellular/satellite and/or other radiotelephone communications systems become operational or change.
Accordingly, there continues to be a need for systems and methods for reducing interference between a WLL and other radiotelephone communications systems.
Summary of the Invention 1 S It is therefore an object of the present invention to provide improved wireless local loop systems and methods.
It is another object of the present invention to provide wireless local loop systems and methods that can reduce interference with cellular, satellite and/or other wireless telecommunications systems.
These and other objects are provided, according to the present invention, by wireless local loops that include primarily non-vertically polarized antennas.
Preferably, the wireless loca~.l loop includes horizontally polarized antennas, By using primarily non-vertically polarized antennas in the wireless local loop, interference between cellular, satellite and/or other radiotelephone communications systems, which employ predominantly vertically polarized antennas, can be reduced and preferably minimized.
The invention stems from the realization that conventional cellular and satellite radiotelephone systems use vertically polarized transmissions due to the vertical nature of the orientation of the mobile antennas on vehicles and/or mobile radiotelephones. However, in a wireless local loop, with its fixed wireless telecommunications, there is no need to use vertically oriented antennas.
Accordingly, to reduce interference, antennas that are primarily non-vertically polarized are used. Preferably, horizontally polarized antennas are used.
More particularly, wireless local loops according to the present invention include a Radio Fixed Part (RFP) including an RFP antenna that is responsive to a switching office, to wirelessly transmit telecommunications mess-ages from the switching office and to wire;lessly receive telecommunications messages for the switching office via the RF:P antenna. The wireless local loop also includes a Wireless Fixed Access Unii; (WFAU) including a WFAU antenna that is responsive to a telephone, to wirelessly transmit telecommunications messages from the telephone to the RFP and to wirelesshr receive telecommunications messages for the telephone from the RFP via the WFAIJ antenna. According to the invention, the RFP
antenna and the WFAU antenna are primarily non-vertically polarized. Preferably, the RFP
antenna is a horizontally polarized RFP antenna and the WFAU antenna is a horizontally polarized WFA,U antenna.
The RFP antenna m;ay be fixedly mounted to a telephone pole or pylon in an orientation that provides primarily non-vertical polarization. Alternatively, the RFP
antenna may be fixedly rr~ounted to a cellular radiotelephone base station in an orientation that provides primarily non-vertical polarization. The WFAU
antenna is fixedly mounted to a building such as a dwelling in an orientation that provides primarily non-vertical polarization.
Wireless local loops according to the invention may also include a network interface and a customer interface that connect the WFAU to the telephone, The telecommunications messages may utilize cordless, cellular and/or other wireless technologies. Accordingly, primarily non-vertically polarized radio frequency telecommunications messages are transmitted between the RFP and the WFAU.
Preferably, horizontally polarized radio frequency telecommunications messages are transmitted between the RFIP and the WFAU. Cross-polarization interference with cellular, satellite and/or othE:r radiotelephone communications system can thereby be reduced.
Brief Description of the Drawings Figure 1 is a block diagram of telecommunications systems including first embodiments of WLL systems and methods according to the present invention.
Figure 2 is a block diagram of telecommunications systems including second embodiments of WLL systems and methods according to the present invention.
Figure 3 graphically illustrates typical response of a vertically polarized antenna to a vertically polarized wave and to a horizontally polarized wave.
Detailed Descrintion of Preferred Embodiments 5 The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein;
rather, these embodiments a.re provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Like numbers refer to like elements throughout.
Referring now to Figure 1, a telecommunications system including first embodiments of wireless local loop systems and methods according to the present invention will be described. As shown in Figure l, the telecommunications system includes a wired telephone system 102 and a wireless radiotelephone system 104.
Wired telephone system 1.0~: includes a switching office 106 that is connected to the Public Switched Telephone Network (PSTN) 108 andlor other networks 112, such as satellite or cellular radiotelephone communications networks. Trunked cables connect the switching office 106 to a plurality of telephone poles or pylons 116. A
wired local loop 118 connects selected ones of the pylons 116 to selected buildings such as dwellings 122. The wired local loop 118 connects to the dwelling via a network interface 124 and a customer interface 126 that may include a standard connector. A telephone 128 is connected to the customer interface 126.
Although telephone 128 is illustrated as being a wired telephone, a mobile or cordless telephone may also be used.
Still referring to Figure 1, a wireless local loop 130 is used to connect a franked cable 114 to a second selected dwelling 122'. The wireless local loop includes a Radio Fixed Part (RFP) 132 that includes an RFP antenna 134 that is responsive to the switching office 106 to wirelessly transmit telecommunications messages from the switching office 106 and to wirelessly receive telecommunications messages for the switching c>ffice 106. The WLL also includes a Wireless Fixed Access Unit (WFAU) 136 that includes a WFAU antenna 138 that is responsive to a telephone 128' to wirelessly transmit telecommunications messages 140 from the telephone 128' to the RFP 1:32, and to wirelessly receive telecommunications messages 140 for the telephone 128 from the RFP 132 via the WFAU antenna 138.
It will be understood by thosE; having skill in the art that although telephone 128' has been designated with a "prime (')" notation, from the customer perspective, it can operate in the same manner as a conventional telephone 128, and includes a S conventional network interface 124 and customer interface 126 between the WFAU
136 and the telephone 128'. As with telephone 128, telephone 128' can be a wired or wireless telephone.
According to the present invention, the RFP antenna 134 and the WFAU
antenna 138 are primarily non-vertically polarized. By "primarily non-vertically polarized", it is meant that the antenna has a greater horizontally polarized component than a vertically polarized component. Accordingly, the term "primarily non-vertically polarized" includes linearly polarized antennas that have a greater horizontal linear polarization than vertical linear polarization, but excludes circularly polarized antennas that have equal vertical and horizontal polarization components. It will be understood that polarization refers to the direction of the electric (E} field vector. Vertical polarization refers to an E field vector that is perpendicular to the earth's surface and horizonl:al polarization refers to an E field vector parallel to the earth's surface.
A primarily non-vertically polarized radio frequency telecommunications message may also be regarded as a radio frequency telecommunication message having an ellipticity that is less than 1, where ellipticity is defined as the ratio of the vertical and horizontal E field component. Preferably, the ellipticity is, or approaches 0. By using primarily non-vertically polarized radio frequency transmissions, the coupling between a vertically polarized antenna such as is commonly used for a mobile communications, far example in the Personal Communications System (PCS) band (1850 MHz-1990 MHfz) may be reduced to -I S dB or more, where cross-polarization refers to the difference in antenna gain to a vertical and horizontal illumination.
Preferably, RFP antenna 134 and WFAU antenna 138 are a horizontally polarized RFP antenna 134 and a horizontally polarized WFAU antenna 138, so that the rejection of vertically polarized radio frequencies may be maximized.
Accordingly, when a cellular radiotelephone system 104 including a Mobile Telephone Switching Office (MTSO) 142 and a plurality of base stations 144 and portable radiotelephones 146 and mobile radiotelephones 148 exist in the same geographic area as the WLL 130, the vertically polarized radiotelephone communications between the base stations 144, the portable radiotelephones 146 and the mobile radiotelephones 148 will preferably minimally interfere with the primarily non-vertically polarized WLL 130. Accordingly, improved performance in the WLL
may be obtained and reduced interference in the existing radiotelephone system may be obtained.
Still referring to Figure l, the RFP 132 is preferably fixedly mounted to a telephone pole or pylon llti in an orientation that provides primarily non-vertical polarization. More preferably, as shown in Figure 1, the RFP antenna 134 is fixedly horizontally mounted to the. telephone pole or pylon 116. Similarly, the WLL
136 is preferably f xedly mounted to the dwelling 122' in an orientation that provides primarily non-vertical polarization. More preferably, as shown in Figure 1, the WFAU antenna is preferably fixedly horizontally mounted to the dwelling 122'.
It will also be understood by those having skill in the art that the telecommunication messagca 140 may utilize cordless or cellular wireless technologies and/or other technologies, the details of which need not be described herein. Depending on the technology employed, the RFP 132 may also be referred to as a "fixed part", a "base station", or a "radio port". The WFAU may also be referred to as a "portable part", a '"Cordless Terminal Adapter (CTA)", a "Fixed Access Unit (FAU)" or a "Wireless Access Fixed Unit (WAFU)". The WLL may also be referred to as a "Radio Local Loop {RLL)".
Referring now to Fil;ure 2, a telephone communications system including second embodiments of WL,L systems and methods according to the invention will now be described. The embodiment of Figure 2 differs from that of Figure 1 in that the RFP 132' is mounted on a cellular radiotelephone base station 144' rather than being mounted on a telephone pole or pylon 116. When the RFP 132' and the RFP
antenna 134" are mounted on a radiotelephone base stations 144', interference between the RFP antenna 1?i4' and a monopole antenna x52 or a patch antenna 154 of the cellular radiotelephone communications system may be severe due to their close proximity. However, since 'the RFP antenna 134' according to the present invention is primarily non-vertically polarized, this interference can be reduced and preferably minimized. The other elemE:nts of Figure 2 are similar to Figure 1 and need not be described again.
Figure 3 illustrates a typical radiation pattern of a patch antenna that may be used for the RFP antenna 1:32 and/or the WFAU antenna 138. As shown in Figure 3, the higher gain' (outer loop) represents a vertically positioned antenna's response to a vertically polarized wave. 'the lower gain (inner loop) is a response to a horizontally polarized wave. The ratio of the outer loop to the inner loop indicates the cross-polarization of the antenna.
As also shown in Figure 2, along the 5 degree azimuth, the cross-polarization is -28 dB, while along the 30 degree azimuth, the cross polarization is -15 dB.
Accordingly, proper antenna selection, positioning and alignment to provide non-vertically polarized transmissions and preferably to provide horizontally polarized transmissions, can reduce and preferably minimize cross-polarization, thereby allowing a maximum rejection of an undesired signal. By using non-vertically polarized radio frequency transmissions, and preferably horizontally polarized radio frequency transmissions, radio links need not be degraded, while allowing a 1 S significant reduction in coupling to surrounding interferers and hence allowing reduction in the interference; in the WLL system. Moreover, if the WLL system causes interference with other mobile communications systems, the cross-polarization reduction can reduce such interference as well.
Reduction in interference may be particularly important for WLL systems which generally use existin" radio frequency spectrum and technologies. For example, WLL may operate: in the PCS frequency band of 1850 MHz-1990 MHz. As a late arrival, WLL may need to coexist with other, much more powerful wireless, cellular andJor PCS systems, often having to share the cellular base station tower.
Accordingly, WLL RFPs and WFAUs may be radiated upon with high intensity uncoordinated RF power that can lead to a rise in interference and increase the probability of call blocking. By using primarily non-vertically polarized radio frequency transmissions, and more preferably horizontally polarized radio frequency telecommunications in the WLL, potential interference can be reduced and preferably minimized.
It will be understood by those having skill in the art that the present invention may be used in combination with other interference-reducing techniques. For , example, it is known to provide a Frequency Division Duplex (FDD) mode in a WLL, wherein the transmit frequency band is separated from the received frequency band, preferably by a large separation, to thereby reduce interference between the transmit and receive circuitry. The present invention may be added to WLL systems that use FDD mode to provide further reduction in interference with non-WLL systems.
Modern WI,L systems may employ miniature base stations that accommodate small duplexers, typically constructed of high dielectric materials and capable of approximately 30 dB of isolation. The present invention can increase this isolation without the need to detrimentally affect other important parameters.
In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention bein~; set forth in the following claims.
HORIZONTALLY POLARIZED ANTENNAS
Field of the Invention This invention relates to telecommunications systems and methods, and more particularly to wireless local loops for telephone communications systems and methods.
Background of the Invention Wireless Local Loops (WLL) are widely used in telecommunications systems.
As is well known to those having skill in the art, a wireless local loop uses a radio to provide a telephone connection to or within a building such as a dwelling. In particular, in a telecommm;iications system, a dwelling is connected to a switching office via a local loop, then through a distribution node and a trunked cable that is connected to the switching; office. Conventionally, the local loop is copper cable buried in the ground or carried on overhead pylons to the dwelling, and the tt-unked cable includes multiple copper pairs. WLL replaces the local loop section with a radio path .rather than a copper cable. Accordingly, WLL replaces the connection from the distribution point to the dwelling with a radio path. All other parts of the network may be left unaffected.
In a WLL, the dist~~ibution point is connected to a radio transmitter, referred to herein as a Radio Fixed Part (RFP), that includes an RFP antenna that is responsive to a switching office to wirelessly transmit telecommunications messages from the switching once and to wirelessly receive teleconununications messages for the switching office via the Rl~P antenna. A Wireless Fixed Access Unit (WFAU) including a WFAU antenna is conventionally mounted on the side of the dwelling and is connected to a telephone using a network interface and customer interface to wirelessly transmit telecommunications messages from the telephone to the RFP
and to wirelessly receive telecommunications messages for the telephone from the RFP
via the WFAU antenna. Accordingly, apart from the WFAU on the side of the 09-06-2000 CA 02.336636 2001-O1-04 .. .. .. .. .. ..
.. .. . .. . . .. . ..
. . . . .. . . .... . ..
... . . .. . . . ..
~ . . . . . .. . . ..
- 7 _ ~ .. .. .. .. .. ..
dwelling, the telephone subscuber need not notice any difference between a wireless local loop and a conventional wired local loop.
WLL is used in many telecommunications systems that do not already have conventional wired local loops. Moreover, for those telecommunications systems that S already have wired local loops, WLL is being used by new operators to provide competition to an existing telephone company.
The design and operata.on of WLL systems are well known to those having skill in the art, and need not be described further herein. See, for example, the textbook entitled "Introduction to Wireless Local Loop" by William Webb, Artech House, 1998; "Low-Tier Wireless Local Loop Radio Systems-Part l:
Introduction", by Yu et al., IEEE Communications Magazine, March 1997, pp. 84-92; and "Low-Tier Wireless .Local Loop Ract'io Systems-Part 2: Comparison of Systems ", by Yu et al., IEEE Communications Magazine, March 1997, pp. 94-98. Also see U.S.
Patents 5,475,735 to Williams et al. entitled "Method ofProviding Wireless Local Loop Operation with Local Mobilil)r~ for a Subscribed Unit' ; x,603,095 to Uola entitled "Radio System and a Subscriber Terminal for a Radio System"; 5,604,789 to L,erman entitled "Method and System for Providing a Digital Wireless Local Loop' ; and Des.
386,186 to Schnetzer et al. entitled "Wireless Local Loop Antenna". The disclosures of these patents and other references are hereby incorporated herein in their entirety by reference.
In general, WLLs do n.ot employ separate radio technologies but rather use an existing radio technology in a~z existing radio frequency band. In fact, as described in the above-cited Webb textbook, at the beginning of 1997, there were some fifteen different types of technologies, and some technologies were supported by more than one manufacturer, resulting in about twenty-five different product offerings.
These technologies include cordless technologies such as the Digital European Cordless Telephone (DECT), PHS which is a Japanese standard for use in the 1895-1918 MHz frequency band, and CT-2, w tech was developed in the United Kingdom as an alternative to analog cordless ihome phones. Cellular technologies rnay also be used, including analog cellular systems, such as Analog Mobile Phone System (AMPS) and the Total Access Communications Systems (TACS), and digital cellular systems including GSM, IS-95 and D-.A.MPS. Other proprietary technologies may also be used.
REPLACEMENT SHEET AMENDED SHEET
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.. .. .. . . .. . ..
.
. . . .. . . .... . ..
.
... . . . . . . . .
.
.. . . ..
- ~a - . .. .. .. .. .. ..
U.S. Patent No. x,444,762 to Frey et al. entitled Method and Apparatus for Reducing Interference Among Cellular Telephone Signals discloses that a directional antennae on aircraft and on cellular telephone base stations, having a polarity opposite that of potentially interfering »ound system signals, minimize signal strength of air cellular signals received by ground cellular stations. Aircraft directional antennae comprise patch antennae or vertical arrays of loop elements or vertical arrays of virtual loop elements. Additionally, air cellular signals are switched to channels not currently in use by ground cellular systems.
PCT Patent WO 98/33338, to TELEFONAKTIEBOLAGET LM ERICSSON, entitled Methad and Apparatus for Reducing Interference Among Cellular Telephone Signals discusses a robust and. frequency-economic point to multipoint radio access microwave system that combines the use of only two frequency bands and alternating polarizations. Base station antennae feeding adjacent sectors from a common base station site operate at least wi~~:h different ones of two set channels.
Moreover, sectors I5 at adjacent base stations sites (e.g., in adjacent cells) which are aligned with the sectors of the first base station site employ either a different set of channels or differing polarization. The tu~o sets of channels can be two sets of frequencies (e.g., FDMA).
REPLACEMENT SHEET AMENDED SHEET
Since WLL systems are present in the same geographic area as cellular, satellite and/or other wireless communications systems and generally use existing technologies, it may be difficult to avoid interference between the WLL
telecommunications messages and existing cellular, satellite and/or other wireless communications messages. Interference may be reduced somewhat by intelligent frequency allocation of the WLL wireless transmissions. However, this frequency allocation may be difficult to perform in view of the many other wireless radiotelephone communications systems that already may be present. Moreover, the frequency allocation may nE:ed to be updated as additional cellular/satellite and/or other radiotelephone communications systems become operational or change.
Accordingly, there continues to be a need for systems and methods for reducing interference between a WLL and other radiotelephone communications systems.
Summary of the Invention 1 S It is therefore an object of the present invention to provide improved wireless local loop systems and methods.
It is another object of the present invention to provide wireless local loop systems and methods that can reduce interference with cellular, satellite and/or other wireless telecommunications systems.
These and other objects are provided, according to the present invention, by wireless local loops that include primarily non-vertically polarized antennas.
Preferably, the wireless loca~.l loop includes horizontally polarized antennas, By using primarily non-vertically polarized antennas in the wireless local loop, interference between cellular, satellite and/or other radiotelephone communications systems, which employ predominantly vertically polarized antennas, can be reduced and preferably minimized.
The invention stems from the realization that conventional cellular and satellite radiotelephone systems use vertically polarized transmissions due to the vertical nature of the orientation of the mobile antennas on vehicles and/or mobile radiotelephones. However, in a wireless local loop, with its fixed wireless telecommunications, there is no need to use vertically oriented antennas.
Accordingly, to reduce interference, antennas that are primarily non-vertically polarized are used. Preferably, horizontally polarized antennas are used.
More particularly, wireless local loops according to the present invention include a Radio Fixed Part (RFP) including an RFP antenna that is responsive to a switching office, to wirelessly transmit telecommunications mess-ages from the switching office and to wire;lessly receive telecommunications messages for the switching office via the RF:P antenna. The wireless local loop also includes a Wireless Fixed Access Unii; (WFAU) including a WFAU antenna that is responsive to a telephone, to wirelessly transmit telecommunications messages from the telephone to the RFP and to wirelesshr receive telecommunications messages for the telephone from the RFP via the WFAIJ antenna. According to the invention, the RFP
antenna and the WFAU antenna are primarily non-vertically polarized. Preferably, the RFP
antenna is a horizontally polarized RFP antenna and the WFAU antenna is a horizontally polarized WFA,U antenna.
The RFP antenna m;ay be fixedly mounted to a telephone pole or pylon in an orientation that provides primarily non-vertical polarization. Alternatively, the RFP
antenna may be fixedly rr~ounted to a cellular radiotelephone base station in an orientation that provides primarily non-vertical polarization. The WFAU
antenna is fixedly mounted to a building such as a dwelling in an orientation that provides primarily non-vertical polarization.
Wireless local loops according to the invention may also include a network interface and a customer interface that connect the WFAU to the telephone, The telecommunications messages may utilize cordless, cellular and/or other wireless technologies. Accordingly, primarily non-vertically polarized radio frequency telecommunications messages are transmitted between the RFP and the WFAU.
Preferably, horizontally polarized radio frequency telecommunications messages are transmitted between the RFIP and the WFAU. Cross-polarization interference with cellular, satellite and/or othE:r radiotelephone communications system can thereby be reduced.
Brief Description of the Drawings Figure 1 is a block diagram of telecommunications systems including first embodiments of WLL systems and methods according to the present invention.
Figure 2 is a block diagram of telecommunications systems including second embodiments of WLL systems and methods according to the present invention.
Figure 3 graphically illustrates typical response of a vertically polarized antenna to a vertically polarized wave and to a horizontally polarized wave.
Detailed Descrintion of Preferred Embodiments 5 The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein;
rather, these embodiments a.re provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Like numbers refer to like elements throughout.
Referring now to Figure 1, a telecommunications system including first embodiments of wireless local loop systems and methods according to the present invention will be described. As shown in Figure l, the telecommunications system includes a wired telephone system 102 and a wireless radiotelephone system 104.
Wired telephone system 1.0~: includes a switching office 106 that is connected to the Public Switched Telephone Network (PSTN) 108 andlor other networks 112, such as satellite or cellular radiotelephone communications networks. Trunked cables connect the switching office 106 to a plurality of telephone poles or pylons 116. A
wired local loop 118 connects selected ones of the pylons 116 to selected buildings such as dwellings 122. The wired local loop 118 connects to the dwelling via a network interface 124 and a customer interface 126 that may include a standard connector. A telephone 128 is connected to the customer interface 126.
Although telephone 128 is illustrated as being a wired telephone, a mobile or cordless telephone may also be used.
Still referring to Figure 1, a wireless local loop 130 is used to connect a franked cable 114 to a second selected dwelling 122'. The wireless local loop includes a Radio Fixed Part (RFP) 132 that includes an RFP antenna 134 that is responsive to the switching office 106 to wirelessly transmit telecommunications messages from the switching office 106 and to wirelessly receive telecommunications messages for the switching c>ffice 106. The WLL also includes a Wireless Fixed Access Unit (WFAU) 136 that includes a WFAU antenna 138 that is responsive to a telephone 128' to wirelessly transmit telecommunications messages 140 from the telephone 128' to the RFP 1:32, and to wirelessly receive telecommunications messages 140 for the telephone 128 from the RFP 132 via the WFAU antenna 138.
It will be understood by thosE; having skill in the art that although telephone 128' has been designated with a "prime (')" notation, from the customer perspective, it can operate in the same manner as a conventional telephone 128, and includes a S conventional network interface 124 and customer interface 126 between the WFAU
136 and the telephone 128'. As with telephone 128, telephone 128' can be a wired or wireless telephone.
According to the present invention, the RFP antenna 134 and the WFAU
antenna 138 are primarily non-vertically polarized. By "primarily non-vertically polarized", it is meant that the antenna has a greater horizontally polarized component than a vertically polarized component. Accordingly, the term "primarily non-vertically polarized" includes linearly polarized antennas that have a greater horizontal linear polarization than vertical linear polarization, but excludes circularly polarized antennas that have equal vertical and horizontal polarization components. It will be understood that polarization refers to the direction of the electric (E} field vector. Vertical polarization refers to an E field vector that is perpendicular to the earth's surface and horizonl:al polarization refers to an E field vector parallel to the earth's surface.
A primarily non-vertically polarized radio frequency telecommunications message may also be regarded as a radio frequency telecommunication message having an ellipticity that is less than 1, where ellipticity is defined as the ratio of the vertical and horizontal E field component. Preferably, the ellipticity is, or approaches 0. By using primarily non-vertically polarized radio frequency transmissions, the coupling between a vertically polarized antenna such as is commonly used for a mobile communications, far example in the Personal Communications System (PCS) band (1850 MHz-1990 MHfz) may be reduced to -I S dB or more, where cross-polarization refers to the difference in antenna gain to a vertical and horizontal illumination.
Preferably, RFP antenna 134 and WFAU antenna 138 are a horizontally polarized RFP antenna 134 and a horizontally polarized WFAU antenna 138, so that the rejection of vertically polarized radio frequencies may be maximized.
Accordingly, when a cellular radiotelephone system 104 including a Mobile Telephone Switching Office (MTSO) 142 and a plurality of base stations 144 and portable radiotelephones 146 and mobile radiotelephones 148 exist in the same geographic area as the WLL 130, the vertically polarized radiotelephone communications between the base stations 144, the portable radiotelephones 146 and the mobile radiotelephones 148 will preferably minimally interfere with the primarily non-vertically polarized WLL 130. Accordingly, improved performance in the WLL
may be obtained and reduced interference in the existing radiotelephone system may be obtained.
Still referring to Figure l, the RFP 132 is preferably fixedly mounted to a telephone pole or pylon llti in an orientation that provides primarily non-vertical polarization. More preferably, as shown in Figure 1, the RFP antenna 134 is fixedly horizontally mounted to the. telephone pole or pylon 116. Similarly, the WLL
136 is preferably f xedly mounted to the dwelling 122' in an orientation that provides primarily non-vertical polarization. More preferably, as shown in Figure 1, the WFAU antenna is preferably fixedly horizontally mounted to the dwelling 122'.
It will also be understood by those having skill in the art that the telecommunication messagca 140 may utilize cordless or cellular wireless technologies and/or other technologies, the details of which need not be described herein. Depending on the technology employed, the RFP 132 may also be referred to as a "fixed part", a "base station", or a "radio port". The WFAU may also be referred to as a "portable part", a '"Cordless Terminal Adapter (CTA)", a "Fixed Access Unit (FAU)" or a "Wireless Access Fixed Unit (WAFU)". The WLL may also be referred to as a "Radio Local Loop {RLL)".
Referring now to Fil;ure 2, a telephone communications system including second embodiments of WL,L systems and methods according to the invention will now be described. The embodiment of Figure 2 differs from that of Figure 1 in that the RFP 132' is mounted on a cellular radiotelephone base station 144' rather than being mounted on a telephone pole or pylon 116. When the RFP 132' and the RFP
antenna 134" are mounted on a radiotelephone base stations 144', interference between the RFP antenna 1?i4' and a monopole antenna x52 or a patch antenna 154 of the cellular radiotelephone communications system may be severe due to their close proximity. However, since 'the RFP antenna 134' according to the present invention is primarily non-vertically polarized, this interference can be reduced and preferably minimized. The other elemE:nts of Figure 2 are similar to Figure 1 and need not be described again.
Figure 3 illustrates a typical radiation pattern of a patch antenna that may be used for the RFP antenna 1:32 and/or the WFAU antenna 138. As shown in Figure 3, the higher gain' (outer loop) represents a vertically positioned antenna's response to a vertically polarized wave. 'the lower gain (inner loop) is a response to a horizontally polarized wave. The ratio of the outer loop to the inner loop indicates the cross-polarization of the antenna.
As also shown in Figure 2, along the 5 degree azimuth, the cross-polarization is -28 dB, while along the 30 degree azimuth, the cross polarization is -15 dB.
Accordingly, proper antenna selection, positioning and alignment to provide non-vertically polarized transmissions and preferably to provide horizontally polarized transmissions, can reduce and preferably minimize cross-polarization, thereby allowing a maximum rejection of an undesired signal. By using non-vertically polarized radio frequency transmissions, and preferably horizontally polarized radio frequency transmissions, radio links need not be degraded, while allowing a 1 S significant reduction in coupling to surrounding interferers and hence allowing reduction in the interference; in the WLL system. Moreover, if the WLL system causes interference with other mobile communications systems, the cross-polarization reduction can reduce such interference as well.
Reduction in interference may be particularly important for WLL systems which generally use existin" radio frequency spectrum and technologies. For example, WLL may operate: in the PCS frequency band of 1850 MHz-1990 MHz. As a late arrival, WLL may need to coexist with other, much more powerful wireless, cellular andJor PCS systems, often having to share the cellular base station tower.
Accordingly, WLL RFPs and WFAUs may be radiated upon with high intensity uncoordinated RF power that can lead to a rise in interference and increase the probability of call blocking. By using primarily non-vertically polarized radio frequency transmissions, and more preferably horizontally polarized radio frequency telecommunications in the WLL, potential interference can be reduced and preferably minimized.
It will be understood by those having skill in the art that the present invention may be used in combination with other interference-reducing techniques. For , example, it is known to provide a Frequency Division Duplex (FDD) mode in a WLL, wherein the transmit frequency band is separated from the received frequency band, preferably by a large separation, to thereby reduce interference between the transmit and receive circuitry. The present invention may be added to WLL systems that use FDD mode to provide further reduction in interference with non-WLL systems.
Modern WI,L systems may employ miniature base stations that accommodate small duplexers, typically constructed of high dielectric materials and capable of approximately 30 dB of isolation. The present invention can increase this isolation without the need to detrimentally affect other important parameters.
In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention bein~; set forth in the following claims.
Claims (24)
1. A Wireless Local Loop (WLL) comprising:
a Radio Fixed Part (132) (RFP) including an RFP antenna (134) that is responsive to a switching office (106) to wirelessly transmit telecommunications messages (140) from the switching office (106) and to wirelessly receive telecommunications messages (140) for the switching office (106) via the RFP
antenna (134); and a Wireless Fixed Access Unit (136) (WFAU) including a WFAU antenna (138) that is responsive to a telephone (128') to wirelessly transmit telecommunications messages (140) from the telephone (128') to the RFP and to wirelessly receive telecommunications messages (140) for the telephone (128') from the RFP (132) via the WFAU antenna (138); characterized by:
the RFP antenna (134) and the WFAU antenna (138) are primarily non-vertically polarized, and the RFP antenna (134) and the WAFU antenna (138) are both fixed antennas.
a Radio Fixed Part (132) (RFP) including an RFP antenna (134) that is responsive to a switching office (106) to wirelessly transmit telecommunications messages (140) from the switching office (106) and to wirelessly receive telecommunications messages (140) for the switching office (106) via the RFP
antenna (134); and a Wireless Fixed Access Unit (136) (WFAU) including a WFAU antenna (138) that is responsive to a telephone (128') to wirelessly transmit telecommunications messages (140) from the telephone (128') to the RFP and to wirelessly receive telecommunications messages (140) for the telephone (128') from the RFP (132) via the WFAU antenna (138); characterized by:
the RFP antenna (134) and the WFAU antenna (138) are primarily non-vertically polarized, and the RFP antenna (134) and the WAFU antenna (138) are both fixed antennas.
2. A WLL according to Claim 1 wherein the RFP antenna (134) is a fixed horizontally polarized RFP antenna (134) and wherein the WFAU antenna (138) is a fixed horizontally polarized WFAU antenna (138).
3. A WLL according to Claim 1 further comprising a telephone pole (116) and a building (122), wherein the RFP antenna (134) is fixedly mounted to the telephone pole (116) in an orientation that provides primarily non-vertical polarization and wherein the WFAU antenna (138) is fixedly mounted to the building (122) in an orientation that provides primarily non-vertical polarization.
4. A WLL according to Claim 2 further comprising a telephone pole (116) and a building (122), wherein the RFP antenna (134) is fixedly horizontally mounted to the telephone pole (116) and wherein the WFAU antenna (138) is fixedly horizontally mounted to the building (122).
5. A WLL according to Claim 1 further comprising a cellular radiotelephone base station (144') and a building (122), wherein the RFP
antenna (134) is fixedly mounted to the cellular radiotelephone base station (144') in an orientation that provides primarily non-vertical polarization and wherein the WFAU
antenna (138) is fixedly mounted to the building (122) in an orientation that provides primarily non-vertical polarization.
antenna (134) is fixedly mounted to the cellular radiotelephone base station (144') in an orientation that provides primarily non-vertical polarization and wherein the WFAU
antenna (138) is fixedly mounted to the building (122) in an orientation that provides primarily non-vertical polarization.
6. A WLL according to Claim 2 further comprising a cellular radiotelephone base station (144') and a building (122), wherein the RFP
antenna (134) is fixedly horizontally mounted to the cellular radiotelephone base station (144') and wherein the WFAU antenna (138) is fixedly horizontally mounted to the building (122).
antenna (134) is fixedly horizontally mounted to the cellular radiotelephone base station (144') and wherein the WFAU antenna (138) is fixedly horizontally mounted to the building (122).
7. A WLL according to Claim 1 further comprising a network interface (124) and a customer interface (126) that connect the WFAU (136) to the telephone (128').
8. A WLL according to Claim 2 further comprising a network interface (124) and a customer interface (126) that connect the WFAU (136) to the telephone (128').
9. A WLL according to Claim 1 wherein the telecommunications messages (140) utilize cordless or cellular wireless technologies.
10. A WLL according to Claim 2 wherein the telecommunications messages (140) utilize cordless or cellular wireless technologies.
11. A Wireless Local Loop (WLL) characterized by fixed primarily non-vertically polarized antennas.
12. A WLL according to Claim 11 wherein the fixed primarily non-vertically polarized antennas are horizontally polarized antennas.
13. A Wireless Local Loop (WLL) characterized by fixed antennas having ellipticity less than one.
14. A WLL according to Claim 13 wherein the ellipticity is zero.
15. A method of wirelessly transmitting radio frequency telecommunications messages (140) between a Radio Fixed Part (132) (RFP) and a Wireless Fixed Access Unit (WFAU) (136) in a Wireless Local Loop (WLL) characterized by:
transmitting primarily non-vertically polarized radio frequency telecommunications messages (140) between the RFP and the WFAU (136), wherein the RFP antenna (134) and the WAFU antenna are both fixed antennas.
transmitting primarily non-vertically polarized radio frequency telecommunications messages (140) between the RFP and the WFAU (136), wherein the RFP antenna (134) and the WAFU antenna are both fixed antennas.
16. A method according to Claim 15 wherein the transmitting step comprises the step of:
transmitting horizontally polarized radio frequency telecommunications messages (140) between the RFP (132) and the WFAU (136).
transmitting horizontally polarized radio frequency telecommunications messages (140) between the RFP (132) and the WFAU (136).
17. A Radio Fixed Part (RFP) (132) for a Wireless Local Loop (WLL) comprising:
an RFP antenna (134) that is responsive to a switching once to wirelessly transmit telecommunications messages (140) from the switching office and to wirelessly receive telecommunications messages (140) for the switching office;
characterized by:
the RFP antenna (134) is primarily non-vertically polarized and fixed.
an RFP antenna (134) that is responsive to a switching once to wirelessly transmit telecommunications messages (140) from the switching office and to wirelessly receive telecommunications messages (140) for the switching office;
characterized by:
the RFP antenna (134) is primarily non-vertically polarized and fixed.
18. An RFP (132) according to Claim 17 wherein the RFP antenna (134) is a horizontally polarized RFP antenna (134).
19. An RFP (132) according to Claim 18 further comprising a telephone pole (116), wherein the RFP antenna (134) is horizontally mounted to the telephone pole (116).
20. An RFP (132) according to Claim 18 further comprising a cellular radiotelephone base station (144'), wherein the RFP antenna (134) is horizontally mounted to the cellular radiotelephone base station (144').
21. A Wireless Fixed Access Unit (WFAU) (136) for a Wireless Local Loop (WLL) comprising:
a WFAU antenna (138) that is responsive to a telephone (128') to wirelessly transmit telecommunications messages (140) from the telephone (128') and to wirelessly receive telecommunications messages (140) for the telephone (128);
characterized by:
the WFAU antenna (138) being fixed and primarily non-vertically polarized.
a WFAU antenna (138) that is responsive to a telephone (128') to wirelessly transmit telecommunications messages (140) from the telephone (128') and to wirelessly receive telecommunications messages (140) for the telephone (128);
characterized by:
the WFAU antenna (138) being fixed and primarily non-vertically polarized.
22. A WFAU (136)according to Claim 21 wherein the WFAU antenna (138) is a horizontally polarized WFAU antenna (138).
23. A WFAU (136) according to Claim 22 further comprising a building, wherein the WFAU antenna (138) is horizontally mounted to the building.
24. A WFAU (136) according to Claim 21 further comprising a network interface and a customer interface that connect the WFAU (136) to the telephone.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US12688798A | 1998-07-31 | 1998-07-31 | |
| US09/126,887 | 1998-07-31 | ||
| PCT/US1999/012893 WO2000007389A1 (en) | 1998-07-31 | 1999-06-08 | Wireless local loops including horizontally polarized antennas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2336636A1 true CA2336636A1 (en) | 2000-02-10 |
Family
ID=22427205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002336636A Abandoned CA2336636A1 (en) | 1998-07-31 | 1999-06-08 | Wireless local loops including horizontally polarized antennas |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP1101370A1 (en) |
| AR (1) | AR023324A1 (en) |
| AU (1) | AU4428699A (en) |
| BR (1) | BR9912657A (en) |
| CA (1) | CA2336636A1 (en) |
| CO (1) | CO5060450A1 (en) |
| NO (1) | NO20010506D0 (en) |
| UY (1) | UY25630A1 (en) |
| WO (1) | WO2000007389A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5308439B2 (en) * | 2007-06-27 | 2013-10-09 | トムソン ライセンシング | Signal control apparatus and method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5832380A (en) * | 1992-03-06 | 1998-11-03 | Aircell Incorporated | Nonterrestrial cellular mobile telecommunication system |
| US5444762A (en) * | 1993-03-08 | 1995-08-22 | Aircell, Inc. | Method and apparatus for reducing interference among cellular telephone signals |
| US5903826A (en) * | 1996-12-06 | 1999-05-11 | Northern Telecom Limited | Extremely high frequency multipoint fixed-access wireless communication system |
| US6304762B1 (en) * | 1996-12-23 | 2001-10-16 | Texas Instruments Incorporated | Point to multipoint communication system with subsectored upstream antennas |
| US5838670A (en) * | 1997-01-29 | 1998-11-17 | Telefonaktiebolaget L M Ericsson | Point to multipoint radio access system |
-
1999
- 1999-06-08 CA CA002336636A patent/CA2336636A1/en not_active Abandoned
- 1999-06-08 AU AU44286/99A patent/AU4428699A/en not_active Abandoned
- 1999-06-08 EP EP99927358A patent/EP1101370A1/en not_active Withdrawn
- 1999-06-08 WO PCT/US1999/012893 patent/WO2000007389A1/en not_active Application Discontinuation
- 1999-06-08 BR BR9912657-5A patent/BR9912657A/en not_active IP Right Cessation
- 1999-07-29 UY UY25630A patent/UY25630A1/en not_active Application Discontinuation
- 1999-07-30 CO CO99048320A patent/CO5060450A1/en unknown
- 1999-07-30 AR ARP990103806A patent/AR023324A1/en not_active Application Discontinuation
-
2001
- 2001-01-30 NO NO20010506A patent/NO20010506D0/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| UY25630A1 (en) | 1999-11-17 |
| AU4428699A (en) | 2000-02-21 |
| NO20010506L (en) | 2001-01-30 |
| BR9912657A (en) | 2001-05-02 |
| WO2000007389A1 (en) | 2000-02-10 |
| CO5060450A1 (en) | 2001-07-30 |
| EP1101370A1 (en) | 2001-05-23 |
| NO20010506D0 (en) | 2001-01-30 |
| AR023324A1 (en) | 2002-09-04 |
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