5G 无线通讯系统之波束成形与到达方向 (DOA) 技术发展

Gain (dBi)
0 -5 -10 -15 -20 -25 -30 -180 -120 -60 0 60 120 180
0 -5 -10 -15 -20 -25 -30 -180 -120 -60 0 60 120 180
Theta (degree)
Theta (degree)
Received array antenna
Photo of the beamformer module System block diagram of the hybrid analog-digital beamformer of 8 FMCW transmitters array.
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Key components in the radar system
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Outlines
• Our Experiences in RF/Microwave System Development 1. X-band FMCW Phased-Array Radar System 2. Hybrid Switched-Beam and Beam-Steering Technologies in a 2D Phased Array Antenna System 3. High Date Rate 2.4GHz Transceiver Design 4. Phased Local Oscillator Design in a Beam Steering
by [ X1 ], [ X 2 ], ,[ X N ]
K N / 2
Measured and simulated S11 of the subarray antenna (1D patches array).
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Built-in Calibration Capability of Array Antenna
Calibration is implemented by tapping each transmitter output and down-converting into I/Q baseband to calculate the correction factors to the weights.
A horizontal plane
A vertical plane
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Transmitted Array Antenna
A horizontal plane (xz-plane)
A vertical plane (yz-plane)
Photograph of the array antennas consisting of 8 subarray antennas made of 1D patches array.
R
The number of the signal
x(m, n) i 1 ai exp[ j i (m 1) jk x sin i cos i (n 1) jk y sin i sin i ] i 1 ci yi n 1 zi m 1
R
x(1, 2) x(1,1) x(2,1) x(2, 2) [X ] x( M ,1) x( M , 2)
(a) MUSIC
(b) MUSIC with spatial smoothing
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Matrix Pencil Algorithm (1)
Distance along x-axis Distance along y-axis (signal amplitude and signal phase) sin i cos i (phase difference along x-axis) sin i sin i (phase difference along y-axis) R
z1N 1 z2 N 1 N 1 zR R N
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[C ] diag{c1, c2 ,, cR }
Matrix Pencil Algorithm (2)
[X ]
[ X ] = [Y ][C ][ Z ]
[ A1 ] : [ X ] deletes first row
Six-pole bandpass filter Four-pole bandpass filter Bandpass filter with SIRs
25 20 15 10 5
25
with Baffle w/o Baffle
20 15 10 5
with Baffle w/o Baffle
Gain (dBi)
Beam-forming and direction-of-arrival (DoA) estimation techniques toward 5G Wireless Communication systems
Ruey-Bing Hwang, Ph. D. Professor and Director Graduate Institute of Communications Engineering Phased-Array Technology Laboratory National Chiao-Tung University Hsinchu, Taiwan
[X ]
L M / 2
Hankel matrix [ X m ]
x(m, 2) x(m,1) x(m, 2) x(m,3) [Xm] x(m, L) x(m, L 1)
[ X1 ] [ X 2 ] [ X ] [ X ] 3 [ Xe ] 2 [ X K ] [ X K+1 ]
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Beam-forming Technique
Simulation
Measurement
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DoA-MUSIC (1)

x1 x2 a (1 ) a ( 2 ) a (3 ) x8
s w1 1 s w2 2 s 3 w 8
([ A2 ] - [ B2 ] )x 0
[ B1 ] : [ X ] deletes last column
= zi : i 1,...R
{( yi , zi ), i 1,, R }
ln yi x i tan [( ) ] ln zi y
1
{( i , i ), i 1,, R }
x(m, N L 1) x(m, N L 2) x(m, N )
[ X N-K+1 ] [ X N-K+2 ] [XN ]
[ Xe ]
[ X e ] is K ( N K 1) Hankel matrix
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Spatial Smoothing
Forward-backward spatial smoothing technique
x
∗
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Spatial Smoothing
In order to solve highly correlated signals, MUSIC with spatial smoothing is utilized.
Antenna System
2
Outlines
• Our Experiences in RF/Microwave System Development 1. X-band FMCW Phased-Array Radar System 2. Hybrid Switched-Beam and Beam-Steering Technologies in a 2D Phased Array Antenna System 3. High Date Rate 2.4GHz Transceiver Design 4. Phased Local Oscillator Design in a Beam Steering
Antenna System
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Functions of this radar system
• X-band (centered @9410MHz, 50MHz bandwidth) Frequency-Modulated Continuous-Wave Radar System (sweep time: 250 s) • DoA (Direction-of-Arrival Estimation): Modified MUSIC(Multiple Signal Classification) Algorithm plus subarray technique • Beam-forming: dynamically manipulate the phase angle of each STALO (Stable Local Oscillator)
steering vector
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DoA-MUSIC (2)
M: number of antenna D: number of target Fig. in Previous page M=8 D=3
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DoA-MUSIC (3)
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DoA-MUSIC (4)
M = 8,D = 2 (Uncorrelated targets) SNR=10dB Incident angle：-13degree,43degree
x(1, N ) x(2, N ) x( M , N ) M N
ห้องสมุดไป่ตู้
1 y [Y ] 1 M 1 y1
1 y2 y2 M 1
1 1 z1 yR [ Z ] 1 z2 yR M 1 M R 1 z R
[ A1 ] , [ B1 ]
[ B1 ] : [ X ] deletes last row
([ A1 ] - [ B1 ] )x 0
([ A1 ] - [ B1 ] )x 0
1,i = yi : i 1,...R
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Matrix Pencil Algorithm (3)
[ A2 ] : [ X ] deletes first column
t f Ts
B
• The distance between the radar and target: C f Ts R 2B • The range resolution::
B
f
R
t
Ts
C 2B
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System Architecture of the Beam-forming Network
1 x ) ( ln yi ) 2 (ln zi )2 ] i sin [( y j 2 x
1
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Matrix Enhancement Matrix Pencil Algorithm
[ X m ] is L (M L 1) Hankel matrix by column m of [ X ]
Operating procedure smart radar
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Principle of FMCW radar system
• The round-trip time can be estimated by the beat-frequency between the transmitting and echo signals (FMCW). • The bandwidth of the LFM signal at baseband determines the range resolution of the radar system. • The linearity of the FM signal is critical for FMCW system.