WO2001039524A2 - Adaptive antenna and network incorporating same - Google Patents

Adaptive antenna and network incorporating same Download PDF

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Publication number
WO2001039524A2
WO2001039524A2 PCT/EP2000/011361 EP0011361W WO0139524A2 WO 2001039524 A2 WO2001039524 A2 WO 2001039524A2 EP 0011361 W EP0011361 W EP 0011361W WO 0139524 A2 WO0139524 A2 WO 0139524A2
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WO
WIPO (PCT)
Prior art keywords
mobile station
signal
adaptive antenna
antenna
network
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Application number
PCT/EP2000/011361
Other languages
French (fr)
Other versions
WO2001039524A3 (en
Inventor
Howard John Thomas
Raymond Owen
Original Assignee
Motorola Limited
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
Application filed by Motorola Limited filed Critical Motorola Limited
Priority to AU15220/01A priority Critical patent/AU1522001A/en
Publication of WO2001039524A2 publication Critical patent/WO2001039524A2/en
Publication of WO2001039524A3 publication Critical patent/WO2001039524A3/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/28—Cell structures using beam steering

Definitions

  • This invention relates to an adaptive network antenna, to a network of adaptive antennae, and particularly, although not exclusively, to an enhanced handover in an adaptive antenna network in a cellular communications network.
  • Adaptive antennae which steer energy toward a required target using a directive pattern facilitating a reduction in the required transmission power through aperture gains as well as reducing the interference caused from other targets.
  • the target is normally a mobile station and interference with other mobile stations in the network occurs if a broad beam is used for the antenna.
  • a mobile station is moving from one cell in the communications network to another cell, a handover from one base transceiver station to another is required, with the handover being controlled by a base station controller.
  • hand- over is performed by taking measurements of the surrounding cells broadcast channels which are transmitted with a fixed antenna beam which may be omnidirectional or formed of sectored beams, for example, each of an azimuthal angle of 120°.
  • the fixed beam antenna is arranged to handover to an adaptive antenna, but because the adaptive antenna needs to locate the mobile station, so the adaptive antenna initially has a broad beam pattern.
  • a broad beam pattern of the adaptive antenna results in a loss of directivity due to the time it takes to estimate the uplink beam direction and translate to the downlink direction.
  • the broad beam pattern of the adaptive antenna also causes brief interference difficulties within the network.
  • the present invention seeks to at least partially mitigate the foregoing disadvantages.
  • an adaptive antenna for use in a cellular communications network, said antenna being connected to means for adaptively varying the beam pattern of said antenna from a broad pattern for locating a mobile station to an optimised beam pattern for said mobile station, and means for ignoring transmitted data signals from said mobile station until said adaptive means has formed said optimised beam pattern.
  • a network of adaptive antennae each adaptive antenna in said network being associated with a respective base transceiver station in a cellular communications network, and means arranged to adapt a beam pattern of a said antenna from a broad pattern for locating a mobile station to an optimised beam pattern for said mobile station, and means for ignoring transmitted data signals from said mobile station until said adaptive antenna means has formed said optimised beam pattern.
  • transmitted data signals e.g. traffic or control data signals
  • handover means is provided for hand- over of communications for a mobile station of concern from an adaptive antenna in one cell of the cellular communications network to another adaptive antenna in another cell of said cellular communications network, whereby handover is not performed until said another adaptive antenna has formed said optimised beam pattern directed toward said mobile station.
  • said another adaptive antenna includes means for determining a handover requirement, which conveniently includes at least one of signal strength, radio link quality, angle of arrival of a signal from said mobile station, timing advance, and delay spread.
  • said handover means includes means for receiving a predetermined signal from said mobile station and, if said predetermined signal meets predetermined criteria, said antenna beam adapting means modify said beam pattern to said optimised beam pattern for said mobile station, and said ignoring means is adapted to prevent hand over until said beam pattern is appropriately optimised and a further said predetermined signal is received.
  • said predetermined signal and said further signal are the same signal differentially spaced in time.
  • said predetermined signal may be a signal known per se selected from one of a random access signal, a handover message signal, an update request signal, and a radio resource management signal.
  • said cellular communications network includes a fixed beam antenna broadcasting one of a sectored pattern and an omnidirectional pattern and transfer means are provided for transferring signals from said fixed antennae to said adaptive antenna.
  • a method of enhancing operability of a cellular communications network including a network of adaptive antennae, each adaptive antenna in said antennae network being associated with a respective base transceiver station in a cell of said communications network, including the steps of:
  • each adaptive antenna is arranged to determine a handover requirement in determination upon at least one of signal strength, radio link quality, angle of arrival of a signal from said target mobile station, timing advance and delay spread.
  • handover from one adaptive antenna to another adaptive antenna is made in dependence upon receipt of a predetermined signal from said target mobile station which may be one of a random access signal, a handover message signal, an update request signal, and a radio resource management signal.
  • a predetermined signal may be one of a random access signal, a handover message signal, an update request signal, and a radio resource management signal.
  • each said adaptive antenna includes a plurality of antenna elements each associated with respective weighting means and said weighting means are modified for producing the optimised beam pattern of said adaptive antenna.
  • said cellular communications network includes a fixed beam antenna broadcasting one of a sectored pattern and an omnidirectional pattern and transfer means are provided for transferring signals from said fixed antennae to said adaptive antenna.
  • Figure 1 shows, in block schematic form, a cellular communications network including an adaptive antenna in accordance with this invention
  • Figures 2 and 3 show, in schematic form, modes of operation of the adaptive antenna in accordance with this invention
  • FIG. 4 shows, in block schematic form, an adaptive antenna array in accordance with this invention.
  • FIG. 5 shows a flow chart of the operation of the an adaptive antenna array in accordance with this invention.
  • like reference numerals denote like parts.
  • a cellular communications network shown in Figure 1 has a base station controller 1 in communication with at least two base transceiver stations 2, 3 that are located in adjacent cells of the cellular communication network.
  • Each base transceiver station is associated with a fixed antennae 4, 5 and an adaptive antenna 6, 7, respectively, each adaptive antenna having a plurality of elements 8, 9 respectively.
  • the adaptive antenna 6 has formed an optimised beam pattern, which in the present example, is a narrow beam pattern directed to the mobile station 10, but as the mobile station 10 enters the cell associated with the base transceiver station 3, so it is desired to handover from base transceiver station 2 to base transceiver station 3.
  • the fixed beam antennae 4, 5 each produce an omnidirectional beam 15, indicated in broken lines, or a sectored beam, indicated by chain broken lines 16, the sectored beam being divided, for example, into three equi- circumferentially spaced segments, although it is to be understood that the invention is not limited to any particular number of sectored segments. It will also be noted from Figure 1 that the pattern produced by the fixed antenna 4 is not shown in the Figure 4 clarity.
  • Figure 2 shows a broad beam configuration of an adaptive antenna, after initial weight iterations have been effected, where it will be observed that an interfering mobile or mobiles, represented by mobile station 100, are within the radiation field produced by a broad beam 71 of the adaptive antenna 7.
  • the weightings of the adaptive antenna 7 be modified to provide beam pattern convergence to produce an optimised, e.g. a narrower, beam 72, which is directed toward the target mobile station 10, whereby radiation produced by the interfering mobile station 100 is not received by the antenna 7 and neither is radiation from the antenna 7 transmitted to the interfering mobile station.
  • FIG. 4 An adaptive antenna of this invention will now be described with reference to Figure 4, in which the antenna array is split into transmit elements 91 and receive elements 92, both of which are steerable through a principal beam direction ⁇ and arranged to produce a wave front indicated by broken lines 73.
  • Each of the elements 91 , 92 is arranged to transmit or receive signals x 1 (t)...x n (t) respectively.
  • the elements 91 are each connected to a respective variable amplifier 41 that are each connected to be driven by a variable weighting device 42, the weighting devices 42 being driven by a beam direction of arrival estimation device 43.
  • the weighting devices 42 transfer a base band transmit signal 44 which is transmitted through the aml plifiers 41 to be radiated by the respective elements 91.
  • the receive elements 92 are each connected to a respective variable amplifier 45 that is connected in an automatic gain (AGC) feedback loop with an AGC control amplifier 46.
  • Each of the amplifiers 47 is connected to a respective variable weighting device 47.
  • Output from the amplifiers 45 is also passed to a signal processor 48 which, via a control algorithm 49, controls the weighting of the devices 47.
  • Output of the devices 47 is summed in a summer 50 to provide a utilisation signal y(t) which is also fed back to the signal processor 48.
  • a first handover or assignment command transmitted from the fixed beam antenna 5, or received by the antenna 5, is used to direct a call from a target mobile station to a radio frequency channel supported either by a serving cell or by a neighbouring base transceiver station which has been identified as a handover target.
  • the handover target measurements are made on the broadcast common channel and as such do not have an associated beam.
  • the mobile station assignment or hand- over request is determined by the base transceiver station 3 which measures the parameters of the radio link to the mobile station.
  • the request from the mobile station is a message in the form of a signal which may be a known form of message, for example a random access signal, a handover message signal, an update request signal, or a radio resource management signal.
  • step 501 it is first determined at step 501 whether there is a need to handover from one channel to another. If it is determined that there is a need to handover then a channel in a target cell is selected 502 and the mobile station sends a first assignment signal to the target channel
  • the signal processor 48 commences rearranging the weightings of the devices 42, 47 to re-form the beam 71 to an optimised beam, e.g. a narrower, directed beam 72. Whilst the beam is being re-formed to the optimised beam, at step
  • the assignment signal received from the mobile station is ignored and handover of traffic data is refused, but the link parameters are collected so that at step 505 the weights of the respective antenna elements are modified to configure the antenna beam pattern.
  • the mobile station transmits a second assignment signal which may be similar to the first assignment signal (or also could be a continuous signal), and if the adaptive antenna beam of the target channel has been appropriately configured then handover is effected.
  • handover from one cell to another is effected only from one optimised beam to another optimised beam so that interference between channels is reduced.
  • the beam could be optimised by providing nulls against specific interfering stations.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

An adaptive antenna for hand over in a cellular communications network has elements (91, 92) which are capable of forming an optimised beam pattern in dependence upon weights of weighting devices (42, 47). A received signal from a mobile station (10) is ignored until the beam of the adaptive antenna has been appropriately optimised for the mobile station. It is only once the beam pattern has been appropriately formed that hand over to a new cell is effected. Thus, hand over is performed from one optimised beam in one cell to an optimised beam in another cell.

Description

ADAPTIVE ANTENNA AND NETWORK INCORPORATING SAME
Background of the Invention
1 . Field of the Invention
This invention relates to an adaptive network antenna, to a network of adaptive antennae, and particularly, although not exclusively, to an enhanced handover in an adaptive antenna network in a cellular communications network.
2. Description of the Related Art
Adaptive antennae are known which steer energy toward a required target using a directive pattern facilitating a reduction in the required transmission power through aperture gains as well as reducing the interference caused from other targets. In a cellular communications network the target is normally a mobile station and interference with other mobile stations in the network occurs if a broad beam is used for the antenna. Where a mobile station is moving from one cell in the communications network to another cell, a handover from one base transceiver station to another is required, with the handover being controlled by a base station controller.
In a known cellular communications network, hand- over is performed by taking measurements of the surrounding cells broadcast channels which are transmitted with a fixed antenna beam which may be omnidirectional or formed of sectored beams, for example, each of an azimuthal angle of 120°. The fixed beam antenna is arranged to handover to an adaptive antenna, but because the adaptive antenna needs to locate the mobile station, so the adaptive antenna initially has a broad beam pattern. During handover, such a broad beam pattern of the adaptive antenna results in a loss of directivity due to the time it takes to estimate the uplink beam direction and translate to the downlink direction. The broad beam pattern of the adaptive antenna also causes brief interference difficulties within the network. Moreover, it will be appreciated that not only does the adaptive antenna beam overlap with other beam patterns of adaptive antennae, but also the adaptive antenna of concern will be in communication with uplinks from unwanted other mobile stations. Additionally, areas of marginal coverage occur which lead to dropped calls.
In a known cellular communications network, hand- over to an adaptive antenna of a broadcast channel occurs prior to setting the beam pattern/direction toward a desired mobile station. This has the forementioned disadvantage of increasing the interference in the network and leading consequently to dropped calls. There is, thus, an overall reduction in the quality of service of the network.
The present invention seeks to at least partially mitigate the foregoing disadvantages.
SUMMARY OF THE INVENTION
According to this invention in its broadest aspect there is provided an adaptive antenna for use in a cellular communications network, said antenna being connected to means for adaptively varying the beam pattern of said antenna from a broad pattern for locating a mobile station to an optimised beam pattern for said mobile station, and means for ignoring transmitted data signals from said mobile station until said adaptive means has formed said optimised beam pattern. According to a further aspect of this invention there is provided a network of adaptive antennae, each adaptive antenna in said network being associated with a respective base transceiver station in a cellular communications network, and means arranged to adapt a beam pattern of a said antenna from a broad pattern for locating a mobile station to an optimised beam pattern for said mobile station, and means for ignoring transmitted data signals from said mobile station until said adaptive antenna means has formed said optimised beam pattern. By ignoring transmitted data signals, e.g. traffic or control data signals, until the optimised beam pattern of the antenna has been formed, so interference between adjacent channels in the cell communications network is reduced, and the power required for said antenna is reduced. Preferably, handover means is provided for hand- over of communications for a mobile station of concern from an adaptive antenna in one cell of the cellular communications network to another adaptive antenna in another cell of said cellular communications network, whereby handover is not performed until said another adaptive antenna has formed said optimised beam pattern directed toward said mobile station.
In a preferred embodiment, said another adaptive antenna includes means for determining a handover requirement, which conveniently includes at least one of signal strength, radio link quality, angle of arrival of a signal from said mobile station, timing advance, and delay spread. Preferably, said handover means includes means for receiving a predetermined signal from said mobile station and, if said predetermined signal meets predetermined criteria, said antenna beam adapting means modify said beam pattern to said optimised beam pattern for said mobile station, and said ignoring means is adapted to prevent hand over until said beam pattern is appropriately optimised and a further said predetermined signal is received.
Conveniently, said predetermined signal and said further signal are the same signal differentially spaced in time.
Advantageously, said predetermined signal may be a signal known per se selected from one of a random access signal, a handover message signal, an update request signal, and a radio resource management signal.
Preferably said cellular communications network includes a fixed beam antenna broadcasting one of a sectored pattern and an omnidirectional pattern and transfer means are provided for transferring signals from said fixed antennae to said adaptive antenna.
According to another aspect of this invention there is provided a method of enhancing operability of a cellular communications network including a network of adaptive antennae, each adaptive antenna in said antennae network being associated with a respective base transceiver station in a cell of said communications network, including the steps of:
(a) receiving a handover target mobile station signal at an adaptive antenna;
(b) ignoring said handover target mobile station signal;
(c) modifying a beam pattern of said adaptive antenna from a broad pattern to an optimised beam pattern directed to said target mobile station, and (d) effecting a hand over of communications to said adaptive antenna only when the beam of said adaptive antenna has been optimised for said target mobile station. Thus, handover of communications for a target mobile station from one adaptive antenna in one cell of the communications network to another adaptive antenna in another cell of the communications network is not performed until the said one adaptive antenna has formed an optimised beam pattern for said target mobile station.
Preferably, each adaptive antenna is arranged to determine a handover requirement in determination upon at least one of signal strength, radio link quality, angle of arrival of a signal from said target mobile station, timing advance and delay spread.
Preferably, handover from one adaptive antenna to another adaptive antenna is made in dependence upon receipt of a predetermined signal from said target mobile station which may be one of a random access signal, a handover message signal, an update request signal, and a radio resource management signal.
Conveniently, each said adaptive antenna includes a plurality of antenna elements each associated with respective weighting means and said weighting means are modified for producing the optimised beam pattern of said adaptive antenna.
Preferably said cellular communications network includes a fixed beam antenna broadcasting one of a sectored pattern and an omnidirectional pattern and transfer means are provided for transferring signals from said fixed antennae to said adaptive antenna.
BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 shows, in block schematic form, a cellular communications network including an adaptive antenna in accordance with this invention, Figures 2 and 3 show, in schematic form, modes of operation of the adaptive antenna in accordance with this invention,
Figure 4 shows, in block schematic form, an adaptive antenna array in accordance with this invention, and
Figure 5 shows a flow chart of the operation of the an adaptive antenna array in accordance with this invention. In the Figures like reference numerals denote like parts.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A cellular communications network shown in Figure 1 has a base station controller 1 in communication with at least two base transceiver stations 2, 3 that are located in adjacent cells of the cellular communication network.
Each base transceiver station is associated with a fixed antennae 4, 5 and an adaptive antenna 6, 7, respectively, each adaptive antenna having a plurality of elements 8, 9 respectively. A target mobile station 10 moving in the direction of arrow headed line
1 1 is currently in the cell associated with base station 2 and the adaptive antenna 6. The adaptive antenna 6 has formed an optimised beam pattern, which in the present example, is a narrow beam pattern directed to the mobile station 10, but as the mobile station 10 enters the cell associated with the base transceiver station 3, so it is desired to handover from base transceiver station 2 to base transceiver station 3. The fixed beam antennae 4, 5 each produce an omnidirectional beam 15, indicated in broken lines, or a sectored beam, indicated by chain broken lines 16, the sectored beam being divided, for example, into three equi- circumferentially spaced segments, although it is to be understood that the invention is not limited to any particular number of sectored segments. It will also be noted from Figure 1 that the pattern produced by the fixed antenna 4 is not shown in the Figure 4 clarity.
Referring now to Figures 2 and 3, Figure 2 shows a broad beam configuration of an adaptive antenna, after initial weight iterations have been effected, where it will be observed that an interfering mobile or mobiles, represented by mobile station 100, are within the radiation field produced by a broad beam 71 of the adaptive antenna 7. What is required is that the weightings of the adaptive antenna 7 be modified to provide beam pattern convergence to produce an optimised, e.g. a narrower, beam 72, which is directed toward the target mobile station 10, whereby radiation produced by the interfering mobile station 100 is not received by the antenna 7 and neither is radiation from the antenna 7 transmitted to the interfering mobile station.
An adaptive antenna of this invention will now be described with reference to Figure 4, in which the antenna array is split into transmit elements 91 and receive elements 92, both of which are steerable through a principal beam direction θ and arranged to produce a wave front indicated by broken lines 73. Each of the elements 91 , 92 is arranged to transmit or receive signals x1(t)...xn(t) respectively. The elements 91 are each connected to a respective variable amplifier 41 that are each connected to be driven by a variable weighting device 42, the weighting devices 42 being driven by a beam direction of arrival estimation device 43. The weighting devices 42 transfer a base band transmit signal 44 which is transmitted through the aml plifiers 41 to be radiated by the respective elements 91.
The receive elements 92 are each connected to a respective variable amplifier 45 that is connected in an automatic gain (AGC) feedback loop with an AGC control amplifier 46. Each of the amplifiers 47 is connected to a respective variable weighting device 47. Output from the amplifiers 45 is also passed to a signal processor 48 which, via a control algorithm 49, controls the weighting of the devices 47. Output of the devices 47 is summed in a summer 50 to provide a utilisation signal y(t) which is also fed back to the signal processor 48. The components of the adaptive antenna, described in relation to
Figure 4, are conventional and further description of the elements and their mode of operation will be apparent to those skilled in the art.
A first handover or assignment command transmitted from the fixed beam antenna 5, or received by the antenna 5, is used to direct a call from a target mobile station to a radio frequency channel supported either by a serving cell or by a neighbouring base transceiver station which has been identified as a handover target. The handover target measurements are made on the broadcast common channel and as such do not have an associated beam. The mobile station assignment or hand- over request is determined by the base transceiver station 3 which measures the parameters of the radio link to the mobile station. The request from the mobile station is a message in the form of a signal which may be a known form of message, for example a random access signal, a handover message signal, an update request signal, or a radio resource management signal. Thus, referring to Figure 5, it is first determined at step 501 whether there is a need to handover from one channel to another. If it is determined that there is a need to handover then a channel in a target cell is selected 502 and the mobile station sends a first assignment signal to the target channel
503 whereupon the signal processor 48 commences rearranging the weightings of the devices 42, 47 to re-form the beam 71 to an optimised beam, e.g. a narrower, directed beam 72. Whilst the beam is being re-formed to the optimised beam, at step
504 the assignment signal received from the mobile station is ignored and handover of traffic data is refused, but the link parameters are collected so that at step 505 the weights of the respective antenna elements are modified to configure the antenna beam pattern. The mobile station transmits a second assignment signal which may be similar to the first assignment signal (or also could be a continuous signal), and if the adaptive antenna beam of the target channel has been appropriately configured then handover is effected. Thus, by the present invention handover from one cell to another is effected only from one optimised beam to another optimised beam so that interference between channels is reduced.
Although the invention has been described in relation to handover of a call from a serving cell to a target handover cell, it is to be understood that the invention may similarly be used for call assignment to a serving cell.
It will also be understood that instead of producing a narrow, directed beam, the beam could be optimised by providing nulls against specific interfering stations.

Claims

I CLAIM:
1. An adaptive antenna for use in a cellular communications network, said antenna being connected to means for adaptively varying the beam pattern of said antenna from a broad pattern for locating a mobile station to an optimised beam pattern for said mobile station, and means for ignoring transmitted data signals from said mobile station until said adaptive means has formed said optimised beam pattern.
2. A network of adaptive antennae, each adaptive antenna in said network being associated with a respective base transceiver station in a cellular communications network, and means arranged to adapt a beam pattern of a said antenna from a broad pattern for locating a mobile station to an optimised beam pattern for said mobile station, and means for ignoring transmitted data signals from said mobile station until said adaptive antenna means has formed said optimised beam pattern.
3. A network as claimed in claim 2, wherein handover means are provided for handover of communications for a mobile station of concern from an adaptive antenna in one cell of the cellular communications network to another adaptive antenna in another cell of said cellular communications network, whereby handover is not performed until said another adaptive antenna has formed said optimised beam pattern directed toward said mobile station.
4. A network as claimed in claim 3, wherein said another adaptive antenna includes means for determining a handover requirement.
5. A network as claimed in claim 4, wherein said means for determining a handover requirement, includes at least one of signal strength, radio link quality, angle of arrival of a signal from said mobile station, timing advance, and delay spread.
6. A network as claimed in claim 3, wherein said hand- over means includes means for receiving a predetermined signal from said mobile station and, if said predetermined signal meets predetermined criteria, said antenna beam a a'pting means modify said beam pattern to said optimised beam pattern for said mobile station, and said ignoring means is adapted to prevent hand over until said beam pattern is appropriately optimised and a further said predetermined signal is received.
7. A network as claimed in claim 6, wherein said predetermined signal and said further signal are the same signal differentially spaced in time.
8. A network as claimed in claim 6, wherein said predetermined signal may be a signal known per se selected from one of a random access signal, a handover message signal, an update request signal, and a radio resource management signal.
9. A network as claimed in claim 2, wherein said cellular communications network includes a fixed beam antenna broadcasting one of a sectored pattern and an omnidirectional pattern and transfer means are provided for transferring signals from said fixed antennae to said adaptive antenna.
10. A method of enhancing operability of a cellular communications network including a network of adaptive antennae, each adaptive antenna in said antennae network being associated with a respective base transceiver station in a cell of said communications network, including the steps of:
(a) receiving a handover target mobile station signal at an adaptive antenna;
(b) ignoring said handover target mobile station signal;
(c) modifying a beam pattern of said adaptive antenna from a broad pattern to an optimised beam pattern directed to said target mobile station, and (d) effecting a handover of communications to said adaptive antenna only when the beam of said adaptive antenna has been optimised for said target mobile station.
11. A method as claimed in claim 10, wherein each adaptive antenna is arranged to determine a handover requirement in determination upon at least one of signal strength, radio link quality, angle of arrival of a signal from said target mobile station, timing advance and delay spread.
12. A method as claimed in claim 11 , wherein handover from one adaptive antenna to another adaptive antenna is made in dependence upon receipt of a predetermined signal from said target mobile station which may be one of a random access signal, a handover message signal, an update request signal, and a radio resource management signal.
13. A method as claimed in claim 10, wherein each said adaptive antenna includes a plurality of antenna elements each associated with respective weighting means and said weighting means are modified for producing the optimised beam pattern of said adaptive antenna.
14. A method as claimed in claim 11 , wherein said cellular communications network includes a fixed beam antenna broadcasting one of a sectored pattern and an omnidirectional pattern and transfer means are provided for transferring signals from said fixed antennae to said adaptive antenna.
PCT/EP2000/011361 1999-11-23 2000-11-13 Adaptive antenna and network incorporating same WO2001039524A2 (en)

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Cited By (4)

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WO2003019814A1 (en) * 2001-08-23 2003-03-06 Siemens Aktiengesellschaft Method for controlling the beam formation in a mobile radio communication system, handover method and base station for the same
WO2007105999A1 (en) * 2006-03-13 2007-09-20 Telefonaktiebolaget Lm Ericsson (Publ) Advanced handover for adaptive antennas
EP1890510A2 (en) * 2006-08-18 2008-02-20 Fujitsu Ltd. Radio communications system and radio communications control method
EP1954091A2 (en) 2007-01-31 2008-08-06 Broadcom Corporation Efficient network hand-off utilizing stored beam-forming information

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US5615409A (en) * 1993-09-27 1997-03-25 Telefonaktiebolaget Lm Ericsson Method and apparatus for transmitting and receiving signals using two classes of channels
WO1998039945A1 (en) * 1997-03-05 1998-09-11 Nokia Telecommunications Oy A method for selecting a signal, and a cellular radio system
US5893033A (en) * 1995-05-24 1999-04-06 Nokia Telecommunications: Oy Methods for making a faster handover, and a cellular radio systems

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5615409A (en) * 1993-09-27 1997-03-25 Telefonaktiebolaget Lm Ericsson Method and apparatus for transmitting and receiving signals using two classes of channels
US5893033A (en) * 1995-05-24 1999-04-06 Nokia Telecommunications: Oy Methods for making a faster handover, and a cellular radio systems
WO1998039945A1 (en) * 1997-03-05 1998-09-11 Nokia Telecommunications Oy A method for selecting a signal, and a cellular radio system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003019814A1 (en) * 2001-08-23 2003-03-06 Siemens Aktiengesellschaft Method for controlling the beam formation in a mobile radio communication system, handover method and base station for the same
WO2007105999A1 (en) * 2006-03-13 2007-09-20 Telefonaktiebolaget Lm Ericsson (Publ) Advanced handover for adaptive antennas
US9426712B2 (en) 2006-03-13 2016-08-23 Telefonaktiebolaget Lm Ericsson (Publ) Advanced handover for adaptive antennas
EP1890510A2 (en) * 2006-08-18 2008-02-20 Fujitsu Ltd. Radio communications system and radio communications control method
EP1890510A3 (en) * 2006-08-18 2013-03-13 Fujitsu Ltd. Radio communications system and radio communications control method
EP1954091A2 (en) 2007-01-31 2008-08-06 Broadcom Corporation Efficient network hand-off utilizing stored beam-forming information
EP1954091A3 (en) * 2007-01-31 2011-07-06 Broadcom Corporation Efficient network hand-off utilizing stored beam-forming information
US9288736B2 (en) 2007-01-31 2016-03-15 Broadcom Corporation Efficient network hand-off utilizing stored beam-forming information

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WO2001039524A3 (en) 2001-12-20
GB9927517D0 (en) 2000-01-19

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