WO2008129114A1 - Procédé amélioré de sondage de canal et appareil utilisant ce procédé - Google Patents

Procédé amélioré de sondage de canal et appareil utilisant ce procédé Download PDF

Info

Publication number
WO2008129114A1
WO2008129114A1 PCT/FI2007/050212 FI2007050212W WO2008129114A1 WO 2008129114 A1 WO2008129114 A1 WO 2008129114A1 FI 2007050212 W FI2007050212 W FI 2007050212W WO 2008129114 A1 WO2008129114 A1 WO 2008129114A1
Authority
WO
WIPO (PCT)
Prior art keywords
receiver
transmitter
phase shifts
antennas
antenna array
Prior art date
Application number
PCT/FI2007/050212
Other languages
English (en)
Inventor
Juha Ylitalo
Original Assignee
Elektrobit Corporation
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 Elektrobit Corporation filed Critical Elektrobit Corporation
Priority to PCT/FI2007/050212 priority Critical patent/WO2008129114A1/fr
Publication of WO2008129114A1 publication Critical patent/WO2008129114A1/fr

Links

Classifications

    • 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
    • H01Q3/30—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 varying the relative phase between the radiating elements of an array
    • H01Q3/34—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 varying the relative phase between the radiating elements of an array by electrical means
    • H01Q3/40—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 varying the relative phase between the radiating elements of an array by electrical means with phasing matrix
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842—Weighted combining
    • H04B7/086—Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Definitions

  • the invention relates to a method for radio channel measurement and parameter estimation. It addresses an improvement of the dynamic range of channel sounding employing a parameter estimation technique, such as EM (Expectation Maximisation) based approaches.
  • EM Expandectation Maximisation
  • SAGE Space Altering Generalized Expectation maximization
  • RIMAX Random Access to Physical Machine
  • Parameter estimation techniques of known art cover a variety of different methods and algorithms.
  • Model-based estimation techniques are used in applications in which resolution better than the classical resolution is desired.
  • the classical delay resolution for a bandwidth of 100 MHz is 1/100 MHz, i.e. 10 ns.
  • the super-resolution techniques can offer a resolution of 1 ns or better in favourable conditions.
  • the model-based techniques employ deconvolution techniques by which e.g. the bandwidth limitation can be mitigated. For example, if an impulse which has extremely wide bandwidth is transmitted through a transmitter (TX) having a bandwidth of B, the output signal (filtered impulse) has a bandwidth of B. In time domain the filtering effect can be expressed with convolution:
  • X(f) ⁇ (f) F(f) (2)
  • ⁇ (f) and F(f) are the Fourier transforms of ⁇ ( ⁇ ) and f( ⁇ ). Since ⁇ (f) is constant for all frequencies the signal X(f) consists of those frequencies which are passed by the transmitter frequency response F(f).
  • High dynamic range is an essential feature of radio channel sounding devices. It is limited mainly by the maximum transmit power, transmitter and receiver antenna gains and the receiver sensitivity. Channel sounding devices are suffering from low transmit power due to the limitations related to the antenna switch. They also suffer small antenna gains when patch antennas with wide patterns are applied.
  • the SAGE algorithm is a post processing tool used in channel sounding devices. It requires rather good signal-to-noise ratio (SNR) to operate reliably. Usually the SNR should be better than 8-10 dB when SAGE is applied. If only limited transmit power is available, which is usually the case with a prior art RF switch with a transmit power of about 26 dBm, this means that the SNR requirement limits the maximum measurement range significantly. This is especially true if wideband multi-antenna data is measured at high carrier frequencies. Thus a basic problem of the prior art technique is the limited dynamic range of measured impulse responses.
  • the SAGE algorithm operates in the antenna domain extracting for example the following characteristics of the wideband radio channel: number of significant propagation paths, Doppler frequency, propagation delays, angle of arrival at the receiver (AoA), i.e. both elevation and azimuth, angle of departure at the transmitter (AoD), i.e. in both elevation and azimuth, polarization matrix of the propagation paths and rotation direction of polarization.
  • channel sounding is performed antenna element by antenna element, which is depicted in Fig. 1.
  • the channel sounder 19 comprises an antenna switching unit (not shown in Fig. 1 ) which switches one antenna of the antenna array 13 at a time to the primary channel sounder device in the receiving end. Therefore, in the depicted example of Fig. 1 , each channel between a single transmitter antenna and a single receiver antenna is measured at a time. It causes the antenna gain at transmitter and receiver to be very small (roughly 0-1 dBi) and the dynamic range of the measurement is therefore very limited.
  • Fig. 1 depicts a principle of basic antenna-domain receiver or transmitter arrangement 10 known in the prior art in evaluating the direction-of-arrival (DoA) in azimuth plane.
  • the antenna-domain arrangement scans all the possible azimuth angles of a patch antenna array 13 e.g. with steps of two degrees and takes into account the complex gain ⁇ k, reference 11a, of each antenna of the antenna array 13 in each direction ⁇ k, reference 12.
  • Each of the patch antennas of the antenna array 13 is at a time connected in antenna domain 14 to a measurement device 19 in which for example SAGE algorithm is utilized.
  • the measurement device 19 includes calibration files of antenna patterns 11 of individual antennas of the antenna array 13 which belongs either to a transmitter or receiver used.
  • the measurement device 19 utilizes said calibration files and received signals when it estimates transmission channels between the transmitter and receiver under test using SAGE algorithm.
  • First alternative is to increase the transmit power.
  • Second alternative is to increase the code length (large processing gain achieved) and third alternative is to average in the time domain.
  • Averaging in time domain gets complicated if the transmitter or receiver is moving.
  • the super-resolution techniques perform the better the higher the SNR is. Thus it is important to develop measurement and data analysis methodology in a way that provides as high SNR as possible.
  • An object of the invention is to provide in MIMO environment a channel sounding arrangement and channel sounding method by which dynamic range of the channel sounding can be increased.
  • the object of the present invention is fulfilled by providing a channel sounding method comprising
  • phase shifted sounding signals are combined coherently for creating a distinct receiver beam and angle of arrival
  • - MIMO channel parameters are estimated using the coherently combined sounding signals in a measurement apparatus, which utilizes a parameter estimation technique.
  • the object of the present invention is fulfilled also by providing a channel sounding arrangement comprising
  • the object of the present invention is fulfilled also by providing a MIMO channel sounder transmitter antenna array which comprises means for providing for each antenna a different phase shift to the sounding signal to be transmitted.
  • the object of the present invention is fulfilled also by providing a MIMO channel sounder receiver antenna array which comprises
  • An advantage of the invention is that the link budget of the measurement can be greatly increased by antenna array gain, which leads to larger measurement range or alternatively to better dynamic range at a specific sounding distance. Thus it improves the quality of radio channel sounding especially in outdoor environments
  • Another advantage of the invention is that it is simple, robust and low-cost.
  • a further advantage of the invention is that it does not require any changes in the estimation algorithm if SAGE algorithm is utilized.
  • a further advantage of the invention is that the antenna gain of an ULA array (Uniform Linear patch Antenna) using the invention can be 7-8 dBi while it is about 0-1 dBi for the prior art patch antenna array.
  • the received signal power can be up to 14-16 dB larger for a single propagation path compared to a case in which patch antennas are employed at the transmitter and the receiver.
  • a further advantage of the invention is that it allows simple dipole antenna arrays with metal backplanes (reflectors) to be used. If ULAs of dipole antennas are used for channel sounding the gain in dynamic range can be up to 20-30 dB.
  • Yet another advantage of the invention is that it allows also the use of two- dimensional planar arrays. Then the beams can be formed and optimised in both azimuth and elevation domains.
  • the idea of the invention is basically as follows:
  • the invention combines the effective fixed beam approach with the SAGE parameter estimation method.
  • the method is called hereafter beamformer-SAGE method.
  • the method enables efficient utilisation of the specific properties of the SAGE using coherently combined antenna-domain signals in desired directions.
  • the receiver has knowledge of the transmitter and receiver beam patterns. In practise this means that the complex beam patterns have been measured when calibrating the transmitter and receiver antenna arrays with the corresponding phasing matrices. Therefore the radio channel is measured by switching the transmitter and receiver beams instead of switching between single antennas like during prior art antenna-domain SAGE process.
  • each impulse response is measured in a co-ordinated fashion employing all the antenna elements of the antenna array at both the transmitter and receiver end. All antenna signals are summed up coherently at the transmitter and receiver which bring high array gains. This reduces any need to use higher transmitter power if better dynamic sounding range is needed.
  • the invention includes an idea of combining beamforming with some known parameter estimation algorithm.
  • Parameter estimation algorithms can be based on super-resolution algorithms. Examples of usable super-resolution algorithms are for example SAGE and RIMAX algorithms as well as ESPRIT, MUSIC and CLEAN algorithms and their derivatives. SAGE and RIMAX are also examples of expectation maximisation algorithms, which are also usable in the current invention. Further scope of applicability of the present invention will become apparent from the detailed description given hereafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
  • Fig. 1 shows a prior art channel sounding antenna arrangement
  • Fig. 2 shows as an example a channel sounding antenna array arrangement according to the invention
  • Fig. 3a shows an exemplary receiver antenna array arrangement according to the invention
  • Fig. 3b shows as an example a Butler matrix suitable for an antenna array of four antennas
  • Fig. 4 shows as an exemplary a flow chart including main stages of the channel sounding using the beamformer-SAGE method.
  • Fig. 1 was discussed in conjunction with the description of the prior art.
  • the beamformer-SAGE method requires specific antenna arrays and beam forming blocks.
  • One simple antenna constellation includes a Uniform Linear Array (ULA) with inter-element spacing of one half of a wavelength and a phase shifting Butler-matrix.
  • ULA Uniform Linear Array
  • Butler-matrix provides such relative phase shifts between different ULA antennas that create M spatially orthogonal beams.
  • a 4 x 4 Butler-matrix has the following phase shifts:
  • the relative phase shifts are the same for one antenna, a reference antenna (column 1 ), and are linearly increasing for the other antennas.
  • the first row corresponds to the relative phase shifts for beam 1
  • the second row corresponds to beam 2, and so on. Beams are directed symmetrically on both sides of the ULA broadside.
  • the Butler-matrix can be integrated into the antenna unit as an analog phase shift network, i.e. an analog delay line. Thus it is very simple and does not require online calibration. Only once-in-a-life-time calibration is needed in the production phase.
  • ULA antenna arrays offer significant gains in the link budget, which determines the dynamic range of the measured impulse responses. If omnidirectional sounding is needed then e.g. three ULAs can be applied in a 3-sector fashion.
  • the beamformer-SAGE method according to the invention is by no means limited to the Butler-matrix and the corresponding orthogonal beams. Any phasing matrix will apply as long as the corresponding beam patterns are appropriately modelled for the channel parameter estimation phase.
  • the beamformer-SAGE method according to the invention gives significant gain in the dynamic range of channel sounding. It improves the quality of radio channel sounding especially in outdoor environments. For example, if a 6-element ULA is applied the array gain of 8 dB is achieved both in transmitter and receiver. Thus, by assuming constant transmitter power the link budget (dynamic range of the measurement) is improved by 16 dB. The gain can be even larger if two- dimensional planar arrays are employed or if reflector type dipoles are used in the ULA. Alternatively, for a specific distance range, the performance and reliability of the SAGE algorithm is greatly improved.
  • the inventive idea is also applicable in a situation where only the receiving end utilizes beamformer-SAGE method.
  • the measurement apparatus comprises calibration files of prior art antenna domain transmitter and calibration files of the beam domain receiver.
  • Fig. 2 illustrates an example of an antenna array 23 arrangement 20 utilized in the beam domain according to the invention both in the transmitter and receiver.
  • all received antenna signals are first fed in antenna domain 24 to a beamformer 25.
  • the beamformer 25 causes a different phase shift to the signals from different antennas of the antenna array 23.
  • the transmitted sounding signal combines coherently in the radio channel into the specific transmit direction.
  • the coherent combination of the phase-shifted signals causes a formation of narrow receiver beam 21.
  • the composite gain is:
  • M is the number of antennas in the antenna array 23 and ⁇ is the complex gain 21a of an individual antenna belonging to the antenna array 23.
  • the antenna signals are fed in a beam domain 26, one beam at a time, to a measurement device 19 where SAGE algorithm is applied.
  • the beamforming gain can be obtained also in the transmitter.
  • sounding signals to be transmitted are inputted from the transmitter device to the beamformer 25 one beam domain channel at a time.
  • the inputted signals are then phase shifted in the beamformer 25 before conveying them to the antennas.
  • the radio channel excited radio waves from different antennas sum up coherently, which causes a narrow transmitter beam 21 to be formed.
  • the formed transmitter beam 21 has a complex antenna gain 21a and a distinct azimuth and elevation angle 22.
  • the antenna gain and said angles of the beam 21 depend on the number of the antennas and the phase shifts used between the antennas.
  • the beamformer 25 used either in the transmitter or receiver is an analog Butler matrix.
  • any kind of phasing matrixes can be applied instead of the Butler matrix.
  • the number of beams can be different from the number of antennas in the ULA.
  • a beamforming matrix which forms more transmitter and/or receiver beams than there are antennas in the transmitter and receiver arrays.
  • the beamforming phase shifts can be readily calculated for any direction of arrival or direction of departure using the well-known array response vector for a linear uniform array:
  • a( ⁇ ) is the array steering vector (antenna specific phase shifts) to the azimuth direction of ⁇
  • d is the inter-element distance between adjacent antennas in the array
  • M is the number of antennas in the antenna array
  • ⁇ is the wavelength of the carrier frequency.
  • a Gaussian, Chebyshev, Bartlett, Hamming or Blackman window function can be applied for the amplitude tapering of the beamforming weight vectors.
  • the window functions are employed to smooth the beam patterns and to decrease the level of the side-lobes.
  • Fig. 3a depicts a block diagram of an exemplary implementation of the invention.
  • An antenna array 33 is connected in antenna domain 34 to a beamformer 35.
  • the antenna array 33 can comprise for example patch antennas, dipole antennas or reflector antennas.
  • the antenna array 33 is two-dimensional.
  • the beam of the antenna array can be formed both in azimuth and elevation domain.
  • the beamformer 35 comprises advantageously phase shifting circuits known in the art. After the phase shift the signals from different antennas are combined coherently in the radio channel to form beam domain signals according to the invention, which are utilized in the channel parameter estimation.
  • the beamformer 35 can be integrated as part of the antenna array 33. From the beamformer 35 phase-shifted and combined antenna signals are fed in the beam domain to an antenna switching unit 37.
  • the antenna switching unit 37 connects one of the beamformer 35 outputs to a measurement apparatus 39 at a time, for example PROPSOUNDTMCS, which makes the channel sounding. It applies advantageously SAGE algorithm for fulfilling the channel sounding.
  • the measurement apparatus 39 can estimate using SAGE algorithm for example the following channel characteristics: number of significant propagation paths, Doppler frequency, propagation delays, angle of arrival at the receiver, i.e. both elevation and azimuth, angle of departure at the transmitter, i.e. in both elevation and azimuth, polarization matrix of the propagation paths and rotation direction of polarization.
  • Fig. 3b depicts one possible solution for the beamformer 35 of a transmitter or receiver.
  • This exemplary embodiment comprises a 4 x 4 Butler matrix 35a, which is essentially an analog phase shift network.
  • four discrete antennas (not shown in Fig. 3b) are connected in the antenna domain 34 to the Butler matrix 35a. The connection is fulfilled by outputs (transmitter) or inputs (receiver) of the Butler matrix, references 34a, 34b, 34c and 34d.
  • the Butler matrix comprises four phase shifting circuits, references 351-354. Each of the phase shifting circuits 351-354 comprises four phase shift elements having different phase shifts.
  • Each of the phase shift circuits comprises in the beam domain 36 an input (transmitter) or output (receiver), references 36a, 36b, 36c and 36d.
  • the inputs or outputs 36a, 36b, 36c and 36d are connected to the antenna switching unit (not shown in Fig. 3b) in the beam domain 36.
  • the antenna switching unit connects one of the inputs of the Butler matrix 35a to the transmitter at a time.
  • the antenna switching unit connects one of the outputs of the Butler matrix 35a to the channel sounder 39.
  • the exemplary phase shifts are depicted in Fig. 3b with four columns in each phase shifting circuit 351-354.
  • the phase shifts of a certain column in each phase shifting circuit correspond to rows of the Butler matrix according to the equation (4).
  • phase shifts in the first columns are the zero phase shift of the reference antenna.
  • Phase shifts for the second antenna can be found in the second column.
  • Phase shifts for the third antenna can be found in the third column and the phase shifts for the fourth antenna can be found in the fourth column of the Butler matrix 35a.
  • the Butler matrix produces spatially orthogonal beams 21 when the phase-shifted signals are coherently combined.
  • the number of the orthogonal beams 21 is determined by the order of the Butler matrix.
  • any kind of phase shift network could advantageously be applied to optimize the number of beam, beam widths, gains and beam directions.
  • the number of beams could also be smaller than the number of antennas in the array.
  • the utilization of the inventive approach to a typical channel sounder measurement can include for example the following steps:
  • Fig. 4 depicts as an exemplary flow chart actual channel sounding steps when implemented in a MIMO environment. The preceding steps before actual measurement are fulfilled before starting a channel sounding process according to the invention.
  • the channel sounding is started in step 40. Both the transmitter and receiver utilized in the channel sounding are on standby mode.
  • step 41 the transmitter begins transmission using a narrow beam 21 transmission in a defined direction.
  • the narrow beam 21 is accomplished by using several antennas to which a measurement signal is inputted through one input of a beamformer.
  • the beamformer comprises some known phasing matrix.
  • the matrix size N equals the number of available antennas of the antenna array 33.
  • the transmitter antenna gain, beam width, azimuth or elevation angle of the beam in beam domain is determined by the number of transmitter antennas and utilized phase shifts between the antennas.
  • step 42 the multipath signals arrive to antennas of the receiver system.
  • the number of antennas utilized can be for example M.
  • the received antenna signals are transferred in antenna domain 34 into a beamformer 35 according to the invention.
  • the beamformer 35 can advantageously be accomplished using a Butler matrix of size M x M.
  • the antenna signals are phase-shifted in the beamformer and after that coherently combined to beam domain signals 36.
  • the coherent combination of the antenna signals in the beamformer causes narrowing of the receiver beam 21 in the beam domain.
  • the antenna gain increases in the direction of the beam 21.
  • an azimuth or elevation angle of the beam domain is determined by the phase shift network.
  • the number of outputted beam domain signals can advantageously be equal to the number of antennas, i.e. M.
  • step 44 beam domain signals of one beamformer 35 output 36a-36d are switched through the antenna switching unit 37 to the channel sounder 39.
  • the channel sounder advantageously utilizes some parameter estimation technique in the channel estimation.
  • step 45 After estimating a received channel, it is checked in step 45, if the channel sounding has been fulfilled for all transmission and receiving beam combinations. If all transmitter beams have been used in the measurement and all those transmissions have been received using all receiver beams, the channel sounding ends in step 46. However, if some of the receiver beams have not been used in the estimation, or if some of the transmitter beams are not yet transmitted, the process returns to step 41 and the process repeats the foregoing process.
  • SAGE is only one example of super-resolution-based algorithms, and any other applicable algorithm, such as RIMAX can also be used. These two are also examples of expectation maximization algorithms.
  • the parameter estimation can be accomplished with any applicable super-resolution algorithm. Examples of such super-resolution algorithms are ESPRIT, MUSIC and CLEAN and their counterparts.

Landscapes

  • Variable-Direction Aerials And Aerial Arrays (AREA)

Abstract

La présente invention concerne un procédé de sondage de canal et un dispositif de mesure permettant d'estimer les caractéristiques du canal de transmission dans un environnement MIMO utilisant un algorithme d'estimation de paramètre. Dans ce procédé, une approche de domaine de faisceau est utilisée lors de la transmission comme de la réception. Dans cette approche, des faisceaux d'émetteur et de récepteur sont créés à l'aide d'un système de formation de faisceau (35). En utilisant ce système (35), la plage dynamique du sondage du canal peut être augmentée comparée au sondage d'un canal de domaine d'antenne. L'invention a aussi trait à des réseaux d'antenne (33) utilisés dans le sondage de canal.
PCT/FI2007/050212 2007-04-23 2007-04-23 Procédé amélioré de sondage de canal et appareil utilisant ce procédé WO2008129114A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/FI2007/050212 WO2008129114A1 (fr) 2007-04-23 2007-04-23 Procédé amélioré de sondage de canal et appareil utilisant ce procédé

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/FI2007/050212 WO2008129114A1 (fr) 2007-04-23 2007-04-23 Procédé amélioré de sondage de canal et appareil utilisant ce procédé

Publications (1)

Publication Number Publication Date
WO2008129114A1 true WO2008129114A1 (fr) 2008-10-30

Family

ID=39875129

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2007/050212 WO2008129114A1 (fr) 2007-04-23 2007-04-23 Procédé amélioré de sondage de canal et appareil utilisant ce procédé

Country Status (1)

Country Link
WO (1) WO2008129114A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8942659B2 (en) 2011-09-08 2015-01-27 Drexel University Method for selecting state of a reconfigurable antenna in a communication system via machine learning
TWI481233B (zh) * 2009-05-29 2015-04-11 Lsi Corp 用於多使用者多輸入多輸出正交分頻多重存取之頻率偏移及頻道回應之同時估計之方法及裝置
US10397811B2 (en) 2016-10-14 2019-08-27 At&T Intellectual Property I, L.P. Wireless channel sounder with fast measurement speed and wide dynamic range
US20210011108A1 (en) * 2019-07-10 2021-01-14 The Board Of Trustees Of The University Of Alabama Method and system for direction finding and channel sounding using pseudo-doppler antenna array

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6392595B1 (en) * 1998-11-04 2002-05-21 Nokia Network Oy Method and apparatus for directional radio communication
US20030157898A1 (en) * 2001-12-28 2003-08-21 Nokia Corporation Method of estimating downlink channel, and user equipment
US20060093065A1 (en) * 2004-11-04 2006-05-04 Thomas Timothy A Method and apparatus for closed loop data transmission
WO2006110737A2 (fr) * 2005-04-07 2006-10-19 Interdigital Technology Corporation Procede et appareil de selection de mappage d'antenne dans des reseaux sans fil mimo-ofdm

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6392595B1 (en) * 1998-11-04 2002-05-21 Nokia Network Oy Method and apparatus for directional radio communication
US20030157898A1 (en) * 2001-12-28 2003-08-21 Nokia Corporation Method of estimating downlink channel, and user equipment
US20060093065A1 (en) * 2004-11-04 2006-05-04 Thomas Timothy A Method and apparatus for closed loop data transmission
WO2006110737A2 (fr) * 2005-04-07 2006-10-19 Interdigital Technology Corporation Procede et appareil de selection de mappage d'antenne dans des reseaux sans fil mimo-ofdm

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
CRAMER R.J-M. ET AL.: "evaluation of an ultra-wide-band propagation channel", IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, vol. 50, no. 5, May 2002 (2002-05-01), pages 561 - 570, XP011068520 *
RICHTER A. ET AL.: "Joint maximum likelihood estimation of specular paths and distributed diffuse scattering", PROCEEDINGS OF 2005 IEEE 61ST VEHICULAR TECHNOLOGY CONFERENCE, VTC 2005-SPRING, vol. 1, 30 May 2005 (2005-05-30) - 1 June 2005 (2005-06-01), pages 11 - 15, XP010855342 *
STEINBAUER M. ET AL.: "The double-directional radio channel", IEEE ANTENNAS AND PROPAGATION MAGAZINE, vol. 43, no. 4, August 2001 (2001-08-01), pages 51 - 63, XP011091614 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI481233B (zh) * 2009-05-29 2015-04-11 Lsi Corp 用於多使用者多輸入多輸出正交分頻多重存取之頻率偏移及頻道回應之同時估計之方法及裝置
US9942078B2 (en) 2009-05-29 2018-04-10 Avago Technologies General Ip (Singapore) Pte. Ltd. Methods and apparatus for simultaneous estimation of frequency offset and channel response for MU-MIMO OFDMA
US8942659B2 (en) 2011-09-08 2015-01-27 Drexel University Method for selecting state of a reconfigurable antenna in a communication system via machine learning
US9179470B2 (en) 2011-09-08 2015-11-03 Drexel University Method for selecting state of a reconfigurable antenna in a communication system via machine learning
US9924522B2 (en) 2011-09-08 2018-03-20 Drexel University Method for selecting state of a reconfigurable antenna in a communication system via machine learning
US10397811B2 (en) 2016-10-14 2019-08-27 At&T Intellectual Property I, L.P. Wireless channel sounder with fast measurement speed and wide dynamic range
US10945142B2 (en) 2016-10-14 2021-03-09 At&T Intellectual Property I, L.P. Wireless channel sounder with fast measurement speed and wide dynamic range
US20210011108A1 (en) * 2019-07-10 2021-01-14 The Board Of Trustees Of The University Of Alabama Method and system for direction finding and channel sounding using pseudo-doppler antenna array

Similar Documents

Publication Publication Date Title
Zhang et al. Multibeam for joint communication and radar sensing using steerable analog antenna arrays
JP3872953B2 (ja) アダプティブアンテナを用いた無線通信装置
EP1344276B1 (fr) Station de base, module de station de base et procédé pour estimer le sens d'arrivée
US6680699B2 (en) Signal reception method and device
Huang et al. Frequency-domain AoA estimation and beamforming with wideband hybrid arrays
US6970722B1 (en) Array beamforming with wide nulls
JP2000196328A (ja) 電波到来方向推定方法およびアンテナ装置
Badawy et al. A simple aoa estimation scheme
Miura et al. A DBF self-beam steering array antenna for mobile satellite applications using beam-space maximal-ratio combination
Kumari et al. A combined waveform-beamforming design for millimeter-wave joint communication-radar
WO2008129114A1 (fr) Procédé amélioré de sondage de canal et appareil utilisant ce procédé
JP3899062B2 (ja) アンテナ装置及びその制御方法
Thazeen et al. An efficient reconfigurable optimal source detection and beam allocation algorithm for signal subspace factorization
Zhang et al. Beam alignment for analog arrays based on Gaussian approximation
Kim et al. DOA estimation in cyclic prefix OFDM systems in LOS mmWave channel using monopulse ratio
EP3632000B1 (fr) Détermination d'une relation de phase électrique dans un réseau de communications
Okkonen Uniform linear adaptive antenna array beamforming implementation with a wireless open-access research platform
Zhou et al. Virtual channel space-time processing with dual-polarization discrete lens antenna arrays
JP3438527B2 (ja) 信号波到来角度推定装置及びアレーアンテナ制御装置
Goto et al. Reduced complexity direction-of-arrival estimation for 2d planar massive arrays: A separation approach
Adrian-Ionut et al. A speed convergence Least Squares Constant Modulus Algorithm for smart antenna beamforming
JP4608893B2 (ja) レーダ装置
Noordin et al. Single-port beamforming algorithm for 3-faceted phased array antenna
Wu et al. Reconfigurable hybrid beamforming for dual-polarized mmWave MIMO channels
Li et al. Enhanced AoA estimation using localized hybrid dual-polarized arrays

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07730699

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07730699

Country of ref document: EP

Kind code of ref document: A1