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Transcript of Doc.: IEEE 802.11-14/1398r0 Submission November 2014 Slide 1 Shiwen He, Haiming Wang Preamble...
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Slide 1 Shiwen He, Haiming Wang
Preamble Sequence for IEEE 802.11aj (45GHz)
Name Company Address Phone Email Shiwen HE
Southeast University (SEU)
2 Sipailou, Nanjing 210096, China
+86-25-5209 1653-3121 (ext.) [email protected]
Haiming WANG +86-25-5209 1653-301 (ext.) [email protected]
Yongming HUANG [email protected]
Wei HONG +86-25-5209 1650 [email protected]
Lvxi YANG [email protected]
Yu WANG [email protected]
Bo SUN ZTE [email protected]
Authors/contributors:
Date: 2014-11-5Presenter: Haiming Wang
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 2
Common preamble introduction
• Preamble is the beginning part of a PPDU—used for packet detection, AGC, frequency/timing synchronizations and channel estimation.
• The SC and OFDM systems for both 540MHz and 1080MHz bandwidth share a common preamble:
– Better support of the coexistence between various types of devices.
– Each device, especially Dual-Mode device (the device which supports SC mode and OFDM mode), needs to achieve packet detection/ synchronization/channel estimation for SIG mechanism only once .
– Appropriate re-sampling mechanism is required.
Given that OFDM and SC Data portions use different sampling rates.
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 3
Common preamble requirements• Low peak side lobe of periodic auto-correlation and low maximum value of
periodic cross-correlation.
− to accurate the timing synchronization
• Large zero correlation zone of periodic auto-correlation and periodic cross-correlation.
− 11aj maximum multipath delay spread: 100ns
− The time of zero correlation zone should be larger than 100ns to eliminate interference of multipath delay.
• The elements of preamble sequence should belong to finite collection of symbols, and low-complexity periodic correlator is needed.
– to simplify transmitter/receiver processing and reduce the power consumption
• Preamble sequence set should contain several sequences.
– to implement the MIMO technology
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 4
Definition of ZCZ sequence set
• The sequence set is called Zero Correlation Zone (ZCZ)
sequence set when the following formula is satisfied:
where, denotes the periodic correlation between and , denotes the
energy of the sequence, denotes the ZCZ length, denotes the number of
ZCZ sequences.
1 2, , , QZ Z Z
,
, 0,, 1, ,0, 1 ,
0, 0 ,i jZ Z
E n i jC n i j Qn Z i j
n Z i j
iZ jZ,i jCZ Z E
Z Q
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 5
Proposed Generator for ZCZ sequence set• The initial mutually orthogonal aperiodic sequence sets:
• The iteration method:
where denotes the length of the column vector ,
and denotes identity matrix and zero matrix of the size ,
, denotes the diagonal
matrix with diagonal element , is element of the Discrete
Fourier Transform (DFT) matrix, is element of the
coefficient matrix, denotes all 1 column vector, denotes Kronecker product.
(0) (0)1,1 1,
(0)
,) (1
( 0),
0
Q
Q Q Q
a a
a a
A
1 1 1
1 1 1
1 1 1
1,
2, 1
,
k k k
k k k
k k k
Q L Q L Q L
k Q L Q L Q L
Q L Q L Q L
k
k
k
k
Q k
k
w
w
w
I 0 0
0 I 0
0 0 I
D 1
B A
A B
1 1 1 11,1 1, Q,1 Q,=Diag , , , , ,k k k kQ QQ L Q L Q L Q Lf f f f D I I I I
L (0), , 1, , , 1, ,i j i Q j Q a 1kQ L
I
1kQ L0 1 1k kQ L Q L
, , 1, , , 1, ,i jw i Q j K
Diag υ
υ , , 1, , , 1, ,i jf i Q j Q
1
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 6
Properties of ZCZ sequence set
• ZCZ sequence set :
− denotes the length of ZCZ sequence, denotes the number of ZCZ sequence,
denotes zero correlation zone of ZCZ sequence.
• The large length of periodic zero correlation zone:
• The coefficient matrix is variable.
• Changing the coefficient matrix to search optimized ZCZ sequence set with
low PSL and CL.
• The elements of ZCZ sequence set belong to the finite alphabet set.
2
3
1 , =21 2 , 3
K
K
Q Q L KZ
Q Q Q Q L K
, ,N Q ZZN Q
Z
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 7
Example of ZCZ sequence set
• A kind of is designed to be 802.11aj preamble sequence .
• The peak side lobe of normalized periodic auto-correlation is 0.1976 and the
maximum value of normalized periodic cross-correlation is 0.3125.
− enhance the robustness of time synchronization
• The length of zero correlation zone is 56.
− the time of zero correlation zone:
− eliminate interference of multipath delay
• Quadriphase sequences:
− simplify receiver processing
• The generation parameters of and are detailed in
annex.
56 / 440MHz=127.3ns
256,4,56Z
256,4,56Z 512, 4,112Z
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 8
Common preamble frame format
• Q-band training field (QTF) is composed of 14 repetitions of ZCZ sequences
which are denoted as .
− Chip-level π/2-QPSK modulation.
− The antenna transmits QTF .
− Using 14 repetitions of is a good tradeoff between PPDU efficiency, preamble
detection/synchronization sensitivity and channel estimation accuracy.
• Preamble det/sync SNR sensitivity matches those for decoding Payload with
MCS0
256iZ
256 , 1,2,3, 4i i Z
thi
256iZ
. . .QTF, 14periods (3584chips), transmitted by the antenna
QTF SIG-A Data
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 9
Packet detection algorithm
• Delay correlation algorithm:
where denotes receiving QTF, denotes the length of ZCZ sequence, denotes
delay correlation of QTF , denotes energy of ZCZ sequence, denotes decision
value.
− If is greater than the certain threshold, and lasts for a certain period, then the
packet is detected.
− 3 repetitions of ZCZ sequence are used for packet detection and AGC convergence.
-1 -1
* 2
0 0
( ) ( ) ( ) , ( ) | |
| ( ) |( )( )
N N
k k
C n r n k N r n k P n r n k N
C nm nP n
r N C
P m
m
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 10
Frequency synchronization algorithm• Frequency synchronization algorithm:
where denotes receiving QTF without frequency offset, denotes the sampling
interval, denotes frequency offset, denotes the angle of .
− The simulation shows that 6 repetitions of ZCZ sequence are a good tradeoff
between PPDU efficiency and frequency synchronization sensitivity.
2 2 ( )
-1 *0
,
( ) ( )
2
offset s offset sj f nT j f n N T
D
koffset
s
r n x n e r n N x n N e
r n k r n k Nf
NT
x sT
offsetf
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 11
Timing synchronization algorithm
• Local correlation algorithm:
where denotes local ZCZ sequence element, denotes timing synchronization
position.
− Timing synchronization is performed coherently with channel estimation.
*
1
( ) 0,1, , 1
arg max
N
m
C n r m n a m n N
n C n
a n
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 12
Channel estimation algorithm
• Linear least square (LS) estimation algorithm
where denotes time domain channel with 56 multipath, is a column vector
which denotes the local ZCZ sequence, denotes chips circular
shift of , denotes the receiving sequences with chips.
− The simulation shows that 5 repetitions of ZCZ sequence are a good tradeoff
between PPDU efficiency and channel estimation sensitivity.
56 1 11 Circ ,0 ,Circ ,1 , ,Circ ,55 NN
h a a a r
56 1h a
Circ , kaa
k
1Nr N
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 13
Conclusion
• ZCZ sequence set and its fast periodic correlator are applied in preamble to simplify receiver processing.
• A common preamble is proposed for different PHY modes.– SC and OFDM MCSs share the same preamble structure.
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 14
Annex
1. Generator of ZCZ sequence set2. Generation parameters of 3. Generation parameters of 4. Simulation of correlation5. Simulation of packet detection6. Simulation of frequency offset estimation7. Simulation of channel estimation
256,4,56Z
256,4,56Z 512, 4,112Z
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 15
Generator of ZCZ sequence set
Decom
position of colum
ns
Kronecker product
Kronecker product
...
......
...
......
......
. . .
. . .
......
......
...
...
...
... ...
Matrix
multiplication
Matrix
multiplication
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 16
Generation parameters of .
• Finite collection of symbols:
• Initial mutually orthogonal aperiodic sequence sets:
• DFT matrix:
• Coefficient matrix:
256,4,56Z
= 1, , 1,j j M
(0)
1 1 1 11 11 1 1 11 1
j j
j j
A
4
1 1 1 11 11 1 1 11 1
j jF
j j
1 11
1 11
j jj j j
j jj j j
W
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 17
Generation parameters of .
• Finite collection of symbols:
• Initial mutually orthogonal aperiodic sequence sets:
• DFT matrix:
• Coefficient matrix:
= 1, , 1,j j M
4
1 1 1 11 11 1 1 11 1
j jF
j j
512,4,112Z
(0)
1, 1 1, 1 1, 1 1, 1
1, 1 1, 1 1, 1 1, 1
1, 1 1, 1 1, 1 1, 1
1, 1 1, 1 1, 1 1, 1
A
1
11
j j jj j j jj j jj j j
W
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 18
Correlation of .
-300 -200 -100 0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Shift chip
Peri
odic
ZC
Z-cc
orr
Periodic cross-correlation of ZCZ sequences
-300 -200 -100 0 100 200 3000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Shift chip
Peri
odic
ZC
Z-ac
orr
Periodic auto-correlation of ZCZ sequence
256,4,56Z
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 19
Packet detection (1)
It is shown that threshold 0.2 is a better choice to satisfy the demand of packet detection sensitivity.
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.910
-5
10-4
10-3
10-2
10-1
100
threshold
mis
sing
det
ectio
n pr
obab
ility
false negative ratio, 1x1 antenna
false negative ratio:SNR=-20dBfalse negative ratio:SNR=-15dBfalse negative ratio:SNR=-10dBfalse negative ratio:SNR=-5dBfalse negative ratio:SNR=0dBfalse negative ratio:SNR=5dBfalse negative ratio:SNR=10dBfalse negative ratio:SNR=15dBfalse negative ratio:SNR=20dB
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.910
-4
10-3
10-2
10-1
threshold
fals
e de
tect
ion
prob
abili
ty
false positive ratio, 1x1 antenna
false positive ratio:SNR=-20dBfalse positive ratio:SNR=-15dBfalse positive ratio:SNR=-10dBfalse positive ratio:SNR=-5dBfalse positive ratio:SNR=0dBfalse positive ratio:SNR=5dBfalse positive ratio:SNR=10dBfalse positive ratio:SNR=15dBfalse positive ratio:SNR=20dB
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 20
Packet detection (2)
It is shown that threshold 0.2 is a better choice to satisfy the demand of packet detection sensitivity.
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.910
-4
10-3
10-2
10-1
100
threshold
mis
sing
det
ectio
n pr
obab
ility
false negative ratio, 2x2 antenna
false negative ratio:SNR=-20dBfalse negative ratio:SNR=-15dBfalse negative ratio:SNR=-10dBfalse negative ratio:SNR=-5dBfalse negative ratio:SNR=0dBfalse negative ratio:SNR=5dBfalse negative ratio:SNR=10dBfalse negative ratio:SNR=15dBfalse negative ratio:SNR=20dB
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.910
-5
10-4
10-3
10-2
10-1
threshold
fals
e de
tect
ion
prob
abili
ty
false positive ratio, 2x2 antenna
false positive ratio:SNR=-20dBfalse positive ratio:SNR=-15dBfalse positive ratio:SNR=-10dBfalse positive ratio:SNR=-5dBfalse positive ratio:SNR=0dBfalse positive ratio:SNR=5dBfalse positive ratio:SNR=10dBfalse positive ratio:SNR=15dBfalse positive ratio:SNR=20dB
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 21
Packet detection (3)
It is shown that threshold 0.2 is a better choice to satisfy the demand of packet detection sensitivity.
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.910
-4
10-3
10-2
10-1
100
threshold
mis
sing
det
ectio
n pr
obab
ility
false negative ratio, 4x4 antenna
false negative ratio:SNR=-20dBfalse negative ratio:SNR=-15dBfalse negative ratio:SNR=-10dBfalse negative ratio:SNR=-5dBfalse negative ratio:SNR=0dBfalse negative ratio:SNR=5dBfalse negative ratio:SNR=10dBfalse negative ratio:SNR=15dBfalse negative ratio:SNR=20dB
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.910
-4
10-3
10-2
10-1
threshold
fals
e de
tect
ion
prob
abili
ty
false positive ratio, 4x4 antenna
false positive ratio:SNR=-20dBfalse positive ratio:SNR=-15dBfalse positive ratio:SNR=-10dBfalse positive ratio:SNR=-5dBfalse positive ratio:SNR=0dBfalse positive ratio:SNR=5dBfalse positive ratio:SNR=10dBfalse positive ratio:SNR=15dBfalse positive ratio:SNR=20dB
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 22
Frequency offset estimation
It is shown that 6 repetitions of ZCZ sequence satisfy the demand of frequency synchronization sensitivity.
-5 0 5 1010
-3
10-2
10-1
100
SNR (dB)
RM
SE
(ppm
)
nTx=4, nRx=4, 540MHz
frequency offset estimation 2 symbolsfrequency offset estimation 4 symbolsfrequency offset estimation 6 symbolsfrequency offset estimation 8 symbols
21F
RMSEF
F denotes the number of frames in simulation, denotes real frequency offset, denotes estimated frequency offset.
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 23
Channel estimation
It is shown that 5 repetitions of ZCZ sequence satisfy the demand of channel estimation sensitivity.
-5 0 5 10-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
SNR (dB)
NM
SE
(dB
)
nTx=4, nRx=4, 540MHz
channel estimation 3 symbolschannel estimation 4 symbolschannel estimation 5 symbolschannel estimation 6 symbols
doc.: IEEE 802.11-14/1398r0
Submission
November 2014
Shiwen He, Haiming WangSlide 24
Thanks for Your Attention.