EP2775563A1 - N'ud de réseau et procédé - Google Patents

N'ud de réseau et procédé Download PDF

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Publication number
EP2775563A1
EP2775563A1 EP13305259.7A EP13305259A EP2775563A1 EP 2775563 A1 EP2775563 A1 EP 2775563A1 EP 13305259 A EP13305259 A EP 13305259A EP 2775563 A1 EP2775563 A1 EP 2775563A1
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EP
European Patent Office
Prior art keywords
codebook
beams
codebooks
antenna elements
phase shift
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP13305259.7A
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German (de)
English (en)
Inventor
Min Zhang
Matthew Baker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcatel Lucent SAS
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Alcatel Lucent SAS
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Filing date
Publication date
Application filed by Alcatel Lucent SAS filed Critical Alcatel Lucent SAS
Priority to EP13305259.7A priority Critical patent/EP2775563A1/fr
Publication of EP2775563A1 publication Critical patent/EP2775563A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture

Definitions

  • the present invention relates to a wireless telecommunications network method and wireless telecommunications network node.
  • Base stations in wireless communication systems provide wireless connectivity to user equipment within a geographic area, or cell, associated with the base station.
  • the wireless communication links between the base station and each of the user equipment typically include one or more downlink (or forward) channels for transmitting information from the base station to the user equipment and one or more uplink (or reverse) channels for transmitting information from the user equipment to the base station.
  • Multiple-input-multiple-output (MIMO) techniques may be employed when the base station and, optionally, the user equipment include multiple antennas.
  • MIMO Multiple-input-multiple-output
  • a base station that includes multiple antennas can transmit multiple independent and distinct signals to multiple user equipment concurrently and on the same frequency band.
  • the radio channel between the base station and the user equipment can be described in terms of NxM links.
  • Each link typically has a time-varying complex gain (i.e. amplitude and phase).
  • This channel state information is measured by the user equipment and fed back to the base station in order to allow the base station to adapt characteristics of the signals transmitted to the user equipment to match it in the most appropriate way to the prevailing channel state.
  • both the base station and the user equipment are configured with the same set of codebooks which define typically phase shifts applied to signals feeding the antennas.
  • the receiver measures characteristics of the signals and estimates which of the set of codebooks would best improve the characteristics of the received signals, and an indication of this codebook is fed back to the transmitter.
  • the transmitter can then apply the phase shifts identified by the indicated codebook to the signals feeding the antennas in order to improve the characteristics of the received signals.
  • Existing techniques typically utilise two codebooks which together provide the required phase shifts.
  • One codebook relates to wideband or long-term channel properties, whilst the other codebook (which is indicated more frequently) relates to sub-band or short-term channel properties.
  • a wireless telecommunications network method comprising: providing a plurality of codebooks, each codebook identifying a phase shift to be applied to each signal to be transmitted by each of a plurality of antenna elements arranged in a plurality of pairs, each pair of antenna elements being spaced apart by a distance greater than a half wavelength of a carrier frequency, each codebook identifying a phase shift to be applied to each signal to generate a plurality of beams, each of which has a different angle of departure.
  • the first aspect recognises that a problem with current codebook structures provided by the standards is that they assume closely-spaced (typically a half wavelength spacing) of the antenna elements of the antenna array and so also assume that the angle of departure (or grid of beam) for each of the transmitted beams should be identical in order to improve the characteristics of the channels being received by the user equipment.
  • the first aspect also recognises that when more widely-spaced antenna elements are utilised within the antenna array, this assumption may not be correct and that the angle of departure of the different beams may need to be different in order to improve the reception characteristics of the channels due to the reduction in correlation as the antenna elements become more widely spaced and differing propagation characteristics experienced by the different beams.
  • a wireless telecommunications network node method may be provided.
  • the method may comprise the step of providing, provisioning or configuring a plurality of codebooks.
  • Each of these codebooks may identify phase shifts that may be applied to those signals which are to be transmitted by each of a plurality of different antenna elements.
  • the antenna elements may be arranged in pairs. Each of the pairs of antenna elements may be spaced apart or separated by a distance which is greater than a half wavelength of a carrier signal.
  • Each of the codebooks then identifies phase shifts that maybe applied to those signals in order to generate different beams, each of which has a different angle of departure. In this way, a codebook is provided which enables different beams to be generated concurrently, each with a different angle of departure. This enables the channel conditions at the receiver to be improved using these different codebooks since beams are generated with the different angles of departure in order to better suit the different conditions experienced by the different beams.
  • the plurality of codebooks identify a phase shift to be applied to each signal to generate the plurality of beams, each of the plurality of beams being spatially divergent with respect to each other.
  • the beams concurrently generated may not be parallel, but m ay be spatially divergent.
  • a subset of the plurality of codebooks identify a phase shift to be applied to each signal to generate a plurality of beams, each of the plurality of beams being spatially orthogonal with respect to each other. Accordingly, beams that are orthogonal (that is to say, they are transmitted at 90° to each other), may be generated using a subset of the codebooks. It will be appreciated that another subset generates beams that are not spatially orthogonal.
  • each codebook comprises a product of one of a plurality of first codebooks and one of a plurality of second codebooks. Accordingly, the codebooks may use existing functionality already provided by the standards, which generates precoding vectors from the product of a first codebook and a second codebook.
  • the first codebook comprises one of plurality of identity matrices and diagonal matrices.
  • the codebooks may use existing functionality already provided by the standards.
  • the first codebook comprises one of plurality of matrices having entries arranged in a number of rows and a number of columns corresponding to the plurality of antenna elements.
  • the second codebook comprises a vector having a number of entries corresponding to the plurality of antenna elements arranged in one of a column and a row.
  • each entry of the product of the first and second codebook is associated with a final phase shift to be applied to each signal transmitted by a corresponding antenna element.
  • W2 may function as a rank 1 matrix.
  • the second codebook comprises one of the plurality of matrices W2, where rank 2 and other higher rank codebooks of W2 are transformed from the rank 1 codebook of W2 by applying a householder transformation to a function of W2.
  • W2 is a rank 2,3,or 4 matrix (W2 has 2,3,4 column vectors).
  • W2 has 2,3,4 column vectors.
  • the method comprises evaluating which of the plurality of first and second codebooks are estimated to provide a desired characteristic of the beams and signalling an indication of which of the plurality of first and second codebooks are estimated to provide the desired characteristic of the beams.
  • the step of signalling the indication comprises signalling a value of m and n.
  • the step of signalling the indication comprises signalling a value of m more frequently than signalling a value of n.
  • spatially orthogonal beams are generated using the first codebook having a value of n of one of 0 and 8 and the second codebook having any value of m.
  • spatially non-orthogonal beams are generated using the first codebook having a value of n between 0 and 15 other than 0 and 8 and the second codebook having any value of m.
  • each pair of antenna elements are spaced apart by a plurality of wavelengths of the carrier frequency.
  • the plurality of antenna elements comprise four antenna elements arranged in two pairs.
  • each pair of antenna elements comprise two cross polarised antenna elements.
  • a wireless telecommunications network node comprising: providing logic operable to provide a plurality of codebooks, each codebook identifying a phase shift to be applied to each signal to be transmitted by each of a plurality of antenna elements arranged in a plurality of pairs, each pair of antenna elements being spaced apart by a distance greater than a half wavelength of a carrier frequency, each codebook identifying a phase shift to be applied to each signal to generate a plurality of beams, each of which has a different angle of departure.
  • the plurality of codebooks identify a phase shift to be applied to each signal to generate the plurality of beams, each of the plurality of beams being spatially divergent with respect to each other.
  • a subset of the plurality of codebooks identify a phase shift to be applied to each signal to generate a plurality of beams, each of the plurality of beams being spatially orthogonal with respect to each other.
  • each codebook comprises a product of one of a plurality of first codebooks and one of a plurality of second codebooks.
  • the first codebook comprises one of plurality of identity matrices and diagonal matrices.
  • the first codebook comprises one of plurality of matrices having entries arranged in a number of rows and a number of columns corresponding to the plurality of antenna elements.
  • the second codebook comprises a vector having a number of entries corresponding to the plurality of antenna elements arranged in one of a column and a row.
  • each entry of the product of the first and second codebook is associated with a final phase shift to be applied to each signal transmitted by a corresponding antenna element.
  • the second codebook comprises one of the plurality of matrices W2, where rank 2 and other higher rank codebooks of W2 are transformed from the rank 1 codebook of W2 by applying a householder transformation to a function of W2.
  • the network node comprises evaluation logic operable to evaluate which of the plurality of first and second codebooks are estimated to provide a desired characteristic of the beams and signalling logic operable to signal an indication of which of the plurality of first and second codebooks are estimated to provide the desired characteristic of the beams.
  • the signalling logic is operable to signal a value of m and n.
  • the signalling logic is operable to signal a value of m more frequently than signalling a value of n.
  • spatially orthogonal beams are generated using the first codebook having a value of n of one of 0 and 8 and the second codebook having any value of m.
  • spatially non-orthogonal beams are generated using the first codebook having a value of n between 0 and 15 other than 0 and 8 and the second codebook having any value of m.
  • each pair of antenna elements are spaced apart by a plurality of wavelengths of the carrier frequency.
  • the plurality of antenna elements comprise four antenna elements arranged in two pairs.
  • each pair of antenna elements comprise two cross polarised antenna elements.
  • a computer program product operable, when executed on a computer, to perform the method steps of the first aspect.
  • current standards specify techniques which utilise codebooks W 1 W 2 to feed back the different phase shifts P 1 to P 4 required to be applied by a phase shifter 10 to signals S 1 to S 4 transmitted from antenna elements 20A to 20D in order to form different beams B 1 and B 2 .
  • the current standards assume certain characteristics of the arrangement of the antenna elements and the resultant required characteristics of the formed beams.
  • the current codebooks assume that the antenna array is made of closely spaced (for example, half wavelength spaced) antenna elements which generate beams having an identical angle of departure from the antenna array.
  • embodiments provide an arrangement where codebooks are provided, provisioned or configured for antenna arrays which have antenna elements spaced apart by a distance which is greater than half a wavelength. These different codebooks provide phase shifts which, when applied to different signals, generate beams having different angles of departure. This enables user equipment to evaluate, based on measurements made regarding the received channel signals, which of the different codebooks would provide the most desirable channel signals when the different phase shifts are applied to the signals transmitted by the antenna elements and beams are formed with different angles of departure.
  • existing codebook feedback arrangements may be utilised, such as using a two-stage codebook structure which feeds back sub-band or short-term channel properties frequently using one codebook and wideband or long-term channel properties less frequently using another codebook.
  • the wideband or long-term channel property codebook may be identical for both closely spaced and widely spaced antenna elements, but the codebook of the sub-band or short-term channel property for widely spaced antenna elements differs, as will be explained in more detail below.
  • user equipment will typically perform measurements of the characteristics of the channels being received.
  • the user equipment is provided with a set of codebooks which define different combinations of phase shifts that can be applied at the base station to the signals being transmitted from its antenna array.
  • the user equipment can evaluate all or a sub-set of these codebooks in order to estimate how those phase shifts would improve the characteristics of the channels being received.
  • the identity of the most appropriate codebooks can then be fed back to the base station in order that the base station may utilise the phase shifts specified within those codebooks in order to improve the conditions of the channels being received by the user equipment.
  • codebooks rather than transmitting information relating to the channel conditions is useful, since this reduces the quantity of feedback required between the user equipment and the base station.
  • codebooks is also constraining, since if these are not provisioned or configured appropriately, then optimal improvements to the channel conditions may not be possible.
  • a two-stage codebook structure W 1 W 2 is provided for a typical cross-polarised or co-polarised antenna array with a half-wavelength spacing.
  • W 1 provides wideband or long-term channel properties
  • W 2 provides sub-band or short-term channel properties.
  • the two-stage codebook structure is used in order to balance overhead and accuracy of channel state information feedback.
  • W 1 is fed back relatively infrequently, such as, for example, every 100 ms, whilst W 2 is fed back more frequently, such as, for example, every 5 ms.
  • varying the value of n will change the angle of departure of both beams transmitted by the four antenna elements so that both beams are together directed at the same one of 16 different angles of departure, specified by the value n.
  • the phase shift between the two beams may be one of eight different phase shifts specified by the value m.
  • the value n may be transmitted using four bits, typically every 100ms, whilst the value m may be transmitted using three bits every 5ms. This helps to generate the two beams with the same required angle of departure and different phase shift in order to improve the channel conditions at the user equipment.
  • this configuration of codebooks is optimised for a calibrated antenna array with correlated antenna elements (typically having a half wavelength spacing and propagation with a single dominant angle of departure path (for example, line of sight).
  • correlated antenna elements typically having a half wavelength spacing and propagation with a single dominant angle of departure path (for example, line of sight).
  • W 1 W 2 [1 e j 2 n ⁇ /16 e j 4 m ⁇ /16 - e j (4 m +2 n ) ⁇ /16 ].
  • W 1 may be configured either as an identity matrix or a diagonal matrix (1, -1, 1, -1) representing long term channel characteristics of a full transmission element widely-spaced antenna array.
  • Other non-orthogonal co-phasing vectors or pre-coding vectors for two polarisations can be found with other combination values of n and m.
  • this codebook can reuse the codebook design structure that currently exists for closely spaced antenna arrays with very limited modification of design in order to support widely spaced antenna arrays.
  • Simply transmitting values of n and m in accordance with current procedures can be used to generate beams with varying angles of departure ⁇ and angles of separation ⁇ in order to improve the channel conditions at the user equipment.
  • the selection between the two codebooks may be indicated by higher level signalling from the base station to the user equipment (since the base station may be aware of which type of antenna array is being utilised), or may be signalled from the user equipment to the base station based on its evaluation of both the standard and modified codebook W 2 , together with feedback for the W 1 code word selection, or together with feedback for the W 2 code word selection.
  • embodiments provide a technique where W 1 is semi-statically measured and fed back from the user equipment where W 1 is used to quantise the phase shift within an antenna pair showing the same polarisation.
  • the standard W 1 codebook arrangement can be applied.
  • W 2 is defined according to the following principles: for a code word represented by W 1 W 2 user equipment can feed back two different phase shift/co-phasing vectors corresponding to different polarisations, even though they share the same long-term quantisation of W 1 ; for a code word represented by W 1 W 2 , two different phase shift/co-phasing vectors can be orthogonal or non-orthogonal.
  • This arrangement provides a codebook that can give improved MIMO performance for widely-spaced, cross-polarised antenna configurations, which is an increasingly common base station antenna configuration. This arrangement can be implemented with only minimal changes to existing standards.
  • program storage devices e.g., digital data storage media, which are machine or computer readable and encode machine-executable or computer-executable programs of instructions, wherein said instructions perform some or all of the steps of said above-described methods.
  • the program storage devices may be, e.g., digital memories, magnetic storage media such as a magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media.
  • the embodiments are also intended to cover computers programmed to perform said steps of the above-described methods.
  • processors may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software.
  • the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared.
  • processor or “controller” or “logic” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), and non volatile storage. Other hardware, conventional and/ or custom, may also be included.
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • ROM read only memory
  • RAM random access memory
  • any switches shown in the Figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the implementer as more specifically understood from the context.
  • any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the invention.
  • any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)
EP13305259.7A 2013-03-07 2013-03-07 N'ud de réseau et procédé Withdrawn EP2775563A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160072567A1 (en) * 2013-04-29 2016-03-10 Lg Electronics Inc. Method and apparatus for transmitting channel state information in wireless communication system
WO2018082659A1 (fr) * 2016-11-04 2018-05-11 Huawei Technologies Co., Ltd. Système et procédé de transmission d'une sélection d'un sous-espace
US20180184441A1 (en) * 2016-09-13 2018-06-28 Telefonaktiebolaget Lm Ericsson (Publ) Mu-mimo communication in systems with antenna subarrays

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US5144322A (en) * 1988-11-25 1992-09-01 The United States Of America As Represented By The Secretary Of The Navy Large-aperture sparse array detector system for multiple emitter location
US20030134664A1 (en) * 2001-10-30 2003-07-17 Gregory Zancewicz System, Method, and apparatus for improving the performance of space division multiple access and other systems that shape antenna beams by employing postdetection polarimetric beamsteering and utilizing genetic algorithms to synthesize beams
WO2008063111A1 (fr) * 2006-11-23 2008-05-29 Telefonaktiebolaget Lm Ericsson (Publ) Diagrammes de rayonnement optimisés
US20110075746A1 (en) * 2009-09-30 2011-03-31 Rheinschmitt Rupert J Transmission of precoding codebook over an air interface

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Publication number Priority date Publication date Assignee Title
US5144322A (en) * 1988-11-25 1992-09-01 The United States Of America As Represented By The Secretary Of The Navy Large-aperture sparse array detector system for multiple emitter location
US20030134664A1 (en) * 2001-10-30 2003-07-17 Gregory Zancewicz System, Method, and apparatus for improving the performance of space division multiple access and other systems that shape antenna beams by employing postdetection polarimetric beamsteering and utilizing genetic algorithms to synthesize beams
WO2008063111A1 (fr) * 2006-11-23 2008-05-29 Telefonaktiebolaget Lm Ericsson (Publ) Diagrammes de rayonnement optimisés
US20110075746A1 (en) * 2009-09-30 2011-03-31 Rheinschmitt Rupert J Transmission of precoding codebook over an air interface

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ALCATEL-LUCENT SHANGHAI BELL ET AL: "Discussion of two-stage feedback proposals", 3GPP DRAFT; R1-104088_FINAL, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE ; 650, ROUTE DES LUCIOLES ; F-06921 SOPHIA-ANTIPOLIS CEDEX ; FRANCE, vol. RAN WG1, no. Dresden, Germany; 20100628, 25 June 2010 (2010-06-25), XP050449535 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160072567A1 (en) * 2013-04-29 2016-03-10 Lg Electronics Inc. Method and apparatus for transmitting channel state information in wireless communication system
US9509383B2 (en) * 2013-04-29 2016-11-29 Lg Electronics Inc. Method and apparatus for transmitting channel state information in wireless communication system
US20180184441A1 (en) * 2016-09-13 2018-06-28 Telefonaktiebolaget Lm Ericsson (Publ) Mu-mimo communication in systems with antenna subarrays
US10616908B2 (en) * 2016-09-13 2020-04-07 Telefonaktiebolaget Lm Ericsson (Publ) MU-MIMO communication in systems with antenna subarrays
WO2018082659A1 (fr) * 2016-11-04 2018-05-11 Huawei Technologies Co., Ltd. Système et procédé de transmission d'une sélection d'un sous-espace
CN110324072A (zh) * 2016-11-04 2019-10-11 华为技术有限公司 用于传输子空间选择的系统和方法
US11082176B2 (en) 2016-11-04 2021-08-03 Futurewei Technologies, Inc. System and method for transmitting a sub-space selection
US11711187B2 (en) 2016-11-04 2023-07-25 Futurewei Technologies, Inc. System and method for transmitting a sub-space selection

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