Doc.: IEEE 802.11-14/1399r0 Submission November 2014 Multi-Carrier Training Field for OFDM...
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doc.: IEEE 802.11-14/1399r0 Submission November 2014 Multi-Carrier Training Field for OFDM Transmission in 802.11aj (45GHz) Authors/contributors: Date: 2014-11-5 Presenter: Haiming Wang Slid e 1 Shiwen He, Haiming Wang N am e C om pany A ddress Phone Em ail Shiwen H E Southeast University (SEU ) 2 Sipailou, Nanjing 210096, China +86-25-5209 1653-3121 (ext.) hesw01@ seu.edu.cn Haim ing W ANG +86-25-5209 1653-301 (ext.) hm wang@ seu.edu.cn G uangshiY U ygs-ymz@ 163.com Y ongm ing H UA NG huangym@ seu.edu.cn LuxiY A N G [email protected] W eiHONG weihong@ seu.edu.cn Bo SU N sun.bo1@ zte.com.cn
Transcript of Doc.: IEEE 802.11-14/1399r0 Submission November 2014 Multi-Carrier Training Field for OFDM...
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Multi-Carrier Training Field for OFDM Transmission in 802.11aj (45GHz)
Authors/contributors:
Date: 2014-11-5Presenter: Haiming Wang
Name Company Address Phone Email
Shiwen HE
Southeast University (SEU)
2 Sipailou, Nanjing 210096, China
+86-25-5209 1653-3121 (ext.)
Haiming WANG +86-25-5209 1653-301 (ext.)
Guangshi YU [email protected]
Yongming HUANG [email protected]
Luxi YANG [email protected]
Wei HONG [email protected]
Bo SUN [email protected]
Slide 1
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Introduction
• Multi-Carrier Training Fields (MCTF) is applied for channel estimation in IEEE 802.11aj OFDM transmission.
• This presentation focuses on the OFDM-MCTF in OFDM transmission.
Slide 2
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MCTF
• Considering the situation of IEEE 802.11aj, there are two objectives for the design of MCTF.
• Low PAPR of the OFDM signals
• Binary sequence for MCTF
Slide 3
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MCTF• All the points of the MCTF are set to the same amplitude with different phase.
The MCTF can be represented by
where is the index of the subcarriers, and indicates the subcarrier’s value.
• As each frequency point obtains the same power, the selection of phase will not affect the performance of channel estimation.
• A sequence with low PAPR is proposed to design.
1, 1,1
N
n nn P = P P
n np -thn
Slide 4
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
PAPR• In the OFDM system with N subcarriers , the PAPR of the transmitted signal is
defined as
where denotes the excepted value operation ， is the time domain signal of .
• The MCTF is designed by using cross entropy algorithm.
• The cross entropy method iteratively optimizes the parameters of the
probability distribution to produce a random variable solution in the
neighborhood of the global optimal solution by minimizing cross entropy
between the associated distribution and the optimal importance sampling
distribution.
where denotes the excepted value operation ， denotes the IFFT transform.
2
10 2
maxPAPR 10log
E
n
n
x
x
nx PE[ ]
2
10 21,1
maxarg min 10log
EN
x
x
P
PP
P
E[ ]
Slide 5
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MCTF based on cross entropy
0 10 20 30 40 50 60 70 80 90 1003
3.5
4
4.5
5
5.5
6the PAPR Curve of Random Sequence and Trainning Sequence
PA
PR
training iteration
Random SequenceTraining Sequence
3.2 dB
The figure shows the lowest PAPR of random sequences for 256 length and training sequences for 256 length in one hundred training iterations. The value of the PAPR for 256-MCTF converged at 70 times.
Slide 6
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MCTF based on cross entropy
128:127 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,1, 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,
1,1, 1, 1,1, 1,1,1,1,1,1,1
=[
,1, 1,
BTF
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, 1,1,1,1,1, 1, 1,1,1, 1,1,1,0,0,0, 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, 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, 1,1,
1,1, 1,1,1,1,1, 1,1, 1,1, 1, 1,1,1,1, 1,1,1, 1, 1, 1,1,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0
,0,0,0]
The 256-MCTF including DC carriers & Null carriers
Slide 7
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MCTF based on CE
0 50 100 1503
3.5
4
4.5
5
5.5
6
6.5the PAPR Curve of Random Sequence and Training Sequence
PA
PR
training iteration
Random Sequence
3.58 dB
0 50 100 1503
3.5
4
4.5
5
5.5
6
6.5the PAPR Curve of Random Sequence and Training Sequence
PA
PR
training iteration
Random SequenceTraining Sequence
3.58 dB
The figure shows the lowest PAPR of random sequences for 512 length and training sequences for 512 length in one hundred training iterations. The value of the PAPR for 512-MCTF converged at 80 times.
Slide 8
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MCTF based on CE
The 512-MCTF including DC carriers & Null carriers
256:255 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,1,
1,1, 1, 1, 1, 1, 1,1,1, 1,
[BTF
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, 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, 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, 1,1,1, 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, 1,1,1,1, 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, 1,
1, 1, 1
,1,0,0,0, 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, 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, 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,
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, 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,
1,1,1,1,
1,1, 1,1, 1,1,1,1, 1,1, 1,1, 1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0, 0,0,0,0,0,0,0,0, ]0,0
Slide 9
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MCTF based on CE
• The MCTF of 512 length obtains PAPR for 3.5 dB the same as the VHT-LTF of 64 length.
NOTE: The sequences calculated including DC carriers and null carriers.
Training FieldPAPR
Length of 64 Length of 128 Length of 256 Length of 512
11ac VHT-LTF 3.5 dB 5.7 dB 8.6 dB 11.6 dB
11aj MCTF - - 3.2 dB 3.6 dB
• The comparison of PAPR between 11aj MCTF and 11ac VHT-VTF
Slide 10
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Conclusion
• The proposed MCTF achieves a PAPR of 3.2 dB for the DFT length of 256 and 3.5 dB for the DFT length of 512.
• The proposed MCTF sequence is a binary sequence.
Slide 11
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Appendix
Slide 12
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Simulation Setup Channel model: IEEE 802.11aj(45 GHz), Conference Scenario Number of distinguishable paths : 18 Packet length: 4096 bytes LDPC codeword length: 672bits Number of channel realizations: 2000 Simulation antennas: 4x4 for 1,2,3,4ss, 2x2 for 1,2ss, 1x1 respectively Modulation and code rate: {QPSK ½} Channel estimation: LS with DFT correction Spatial Extension Matrix:
1
11for 1ss
12
1
10
011for 2ss
102
01
100
0103for 3ss
0012
100
1 0 0 0
0 1 0 0for 4ss
0 0 1 0
0 0 0 1
Slide 13
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
PER Performance
3.5 4 4.5 5 5.5 6 6.5 7 7.510
-2
10-1
100
SNR(dB)
PE
RPER,4X4-QPSK-4s
idealestimated
1.5 dB
• Antenna: 4x4; Modulation: QPSK; Stream: 4;• Channel Estimation: LS estimation with correction; • The gap is 1.5 dB.
Slide 14
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
PER Performance
1 2 3 4 5 6 710
-2
10-1
100
SNR(dB)
PE
R
PER,4X4-QPSK-3s
idealestimated
1.5 dB
• Antenna: 4x4; Modulation: QPSK; Stream: 3;• Channel Estimation: LS estimation with correction • The gap is 1.5 dB.
Slide 15
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
PER Performance
-2 -1.5 -1 -0.5 0 0.5 1 1.510
-2
10-1
100
SNR(dB)
PE
R
PER,4X4-QPSK-2s
idealestimated
1.5 dB
• Antenna: 4x4; Modulation: QPSK; Stream: 2;• Channel Estimation: LS estimation with correction. • The gap is 1.5 dB.
Slide 16
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
PER Performance
-6 -5.5 -5 -4.5 -4 -3.5 -3 -2.5 -2 -1.510
-2
10-1
100
SNR(dB)
PE
R
PER,4X4-QPSK-1s
idealestimated
2 dB
• Antenna: 4x4; Modulation: QPSK; Stream: 1;• Channel Estimation: LS estimation with correction; • The gap is 2 dB.
Slide 17
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
PER Performance
2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 710
-2
10-1
100
SNR(dB)
PE
RPER,2X2-QPSK-2s
idealestimated
1.25 dB
• Antenna: 2x2; Modulation: QPSK; Streams 2; • Channel Estimation: LS estimation with correction; • The gap is 1.25 dB.
Slide 18
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
PER Performance
0.5 1 1.5 2 2.5 3 3.5 4 4.5 510
-2
10-1
100
SNR(dB)
PE
R
PER,1x1-QPSK-1s
idealestimated
1.25 dB
• Antenna:1x1; Modulation: QPSK; Stream: 1;• Channel Estimation: LS estimation with correction • The gap is 1.25 dB.
Slide 19
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
MSE Performance of Channel Estimation
• Antenna: 1x1; • Stream: 1; • Channel Estimation: LS estimation with correction
0 2 4 6 8 10 12 14 16 18 2010
-3
10-2
10-1
100
SNR(dB)
MS
EMSE,2X2-2s
Slide 20
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Q & A
1. The gap of the PER curve of ideal and estimated
channel is actual?
• The gap is similar in some other simulations.
• The next two figure contrast the PER gap of ideal and estimated
channel between IEEE 802.11n and IEEE 802.11aj with MCTF.
Slide 21
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Q & A
• Reference ： Hoefel, R. P. F. (2012). IEEE 802.11n: On Performance of Channel
Estimation Schemes over OFDM MIMO Spatially-Correlated Frequency Selective Fading
TGn Channels. In XXX Brazilian Symposium on Telecommunications.
This figure indicated that the PER gap of ideal and LS estimated
channel is about 3 dB in such simulation setup: Simulation
antennas:1x1, Modulation:16QAM.
Slide 22
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Q & A
5 6 7 8 9 10 1110
-2
10-1
100
SNR(dB)
PE
R
PER,1X1-16QAM-1s
idealestimated
1.1 dB
• The corresponding simulation results of MCTF in IEEE 802.11aj in such
simulation setup: Antenna:1x1, Modulation: 16QAM.
• This figure indicates that the PER gap of ideal and estimated channel is
about 1.2dB. The enhancement of the performance is because of the LS
estimation with DFT correction.
Slide 23
doc.: IEEE 802.11-14/1399r0
Submission
November 2014
Shiwen He, Haiming Wang
Thanks for Your Attention!
Slide 24
