Transcript 22-06-0127-02-0000 - IEEE 802 LAN/MAN Standards Committee

July 2006
doc.: IEEE 802.22-06/0127r2
Sensing Schemes for DVB-T
Authors:
IEEE P802.22 Wireless RANs
Name
Company
Address
Date: 2006-07-19
Phone
email
Linjun Lv
Huawei Technologies
Shenzhen, China
0086-755-28973119
[email protected]
Soo-Young Chang
Huawei Technologies
Davis, CA, U.S.
1-916 278 6568
[email protected]
Zhou Wu
Huawei Technologies
Shenzhen, China
86-755-28979499
[email protected]
Jun Rong
Huawei Technologies
Shenzhen, China
86-755-28979499
[email protected]
Mingwei Jie
Huawei Technologies
Shenzhen, China
86-755-28972660
[email protected]
Jianwei Zhang
Huawei Technologies
Shanghai, China
86-21-68644808
[email protected]
Lai Qian
Huawei Technologies
Shenzhen, China
86-755-28973118
[email protected]
Jianhuan Wen
Huawei Technologies
Shenzhen, China
86-755-28973121
[email protected]
Jun Wang
UESTC
Chengdu, China
86-28-83206693
[email protected]
Shaoqian Li
UESTC
Chengdu, China
86-28-83202174
[email protected]
Qihang Peng
UESTC
Chengdu, China
86-13096307946
[email protected]
Lei Chen
UESTC
Chengdu, China
86-13880765377
[email protected]
Meng Zeng
UESTC
Chengdu, China
86-13568886741
[email protected]
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Huawei
Carl
R. Stevenson as early as possible, in written or electronic form, if patented technology
developed
Submission
Slide (or
1 technology under patent application) might be incorporated into a draft standard being
within the IEEE 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at [email protected].
>
July 2006
doc.: IEEE 802.22-06/0127r2
Introduction
• OFDM modulation is adopted by DVB-T systems.
• Two modes of DVB-T: 2k mode and 8k mode
• Two hypotheses for presence and absence of DVB-T signals
Lh 1

H1 : r  k    hl s  k  l   n  k 
l 0

H : r  k   n  k 
 0
where r(k) denotes the kth sample of the received signal in the time
domain, s(k) denotes DVB-T signals transmitted, and hl denotes
coefficient of the lth received path.
• Several methods to realize detection of DVB-T signals are
suggested
Submission
Slide 2
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
(1) Sliding correlation detection based on cyclic prefixes
CP
0
•
•
•
•
N
L
N  L 1
N denotes the number of sub-carriers of an OFDM symbol,
L denotes the length of the cyclic prefixes (CPs).
Then the length of a OFDM symbol in time domain is N+L.
As shown in the figure above, because the first L samples of the
OFDM symbol are the cyclic prefix which is the same as the last L
samples. Therefore the samples in prefix have strong correlation with
the samples in the end part of the same OFDM symbol.
Submission
Slide 3
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
Implementation
Sliding correlation detection based on cyclic prefixes
r(k)
Conjugation
Acumulate
(L points)
module
geting
maximum
decision
Delay N
• Sliding correlation of received signals r(k) and r(k+N)*
 B _ CP 
  L 1

r  k  r  k  N 
k
– If a DVB-T signal exists in the received signal, then
there is a peak in the result while  varies from 0 to N+L-1.
– Otherwise, only the correlation varies randomly.

Submission
: delay between received signals and transmitted signals in real environment
Slide 4
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
(2) Detection algorithms based on IFFT of pilots
• Two hypotheses for presence and absence of DVB-T
signals
L 1

H1 : r  k    hl  st  k  l   m  k  l    n  k 
h
l 0

H : r  k   n  k 
 0
• (N-Np) data sub-carriers
• Np pilots
st  k  
1
N
mk  
1
N

n0, , N 1\ 
 p e
n
xn e j 2 kn / N
j 2 kn / N
n
Two implementations are suggested as in the following slides.
N: no. of subcarriers, Np: no. of pilot subcarriers
Submission
Slide 5
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
Implementation 1
Sliding correlation based on time domain pilots
• Similar to sliding correlation detection based on cyclic
prefixes
• Sliding correlation of received signal r(k) and m(k)
 P1 
•
  N  L 1

r  k  m  k  
k
If a DVB-T signal exists in the received signal, then there
is a peak in the result.
Otherwise, only the correlation varies randomly.
Submission
Slide 6
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
Implementation 2
Sliding correlation on time domain pilots in cyclic prefixes
r(k)
+
Acumulate
(L points)
Conjugation
Delay N
module
decision
m(k-0 )
• Sliding correlation to reduce correlation calculation
: L  (N+L) multiplications
 P2 
Submission
  L 1
  r  k   r  k  N   m  k   

k
Slide 7
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
(3) Joint detection with multiple antennas
• Multiple antenna detection model

H1 : x  n  k   hs  k   w  n  k 


H 0 : x  n  k   w  n  k 
• Statistics of this detection
1
c n 
where
m 
2
m
H
ˆ 1  n  rˆ  n 
ˆ
r
n
R


xm
xx
xm
2
N  L 1

m k 
2
k 0
rˆxm  n  
N  L 1
 xn  k  m k 
k 0
ˆ  n 
R
xx
Submission

N  L 1
 x n  k  x n  k 
H
k 0
Slide 8
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
Simulation 1
ROC for Pf=0.01 under Variable SNR
1
A
B
C
D
E
0.9
Probability of Miss Detection
0.8
0.7
in ATSC
channel
(Pf=0.01)
0.6
0.5
0.4
0.3
0.2
0.1
0
•
•
•
•
•
Submission
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
ATSC A/74, “ATSC
Recommended Practice:
Receiver Performance
Guidelines”.
A: sliding correlation detection based on cyclic prefixes
B: sliding correlation based on time domain pilots
C: sliding correlation based on time domain pilot signals in cyclic prefix
D: joint detection with multi-antennas
E: energy detection
Slide 9
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
Simulation 2
ROC for Pf=0.05 under Variable SNR
1
algorithm1
algorithm2
algorithm3
algorithm4
algorithm5
0.9
Probability of Miss Detection
0.8
0.7
in ATSC
channel
(Pf=0.05)
0.6
0.5
0.4
0.3
0.2
0.1
0
•
•
•
•
•
Submission
-20
-18
-16
-14
-12
-10
SNR(dB)
-8
-6
-4
-2
0
A: sliding correlation detection based on cyclic prefixes
B: sliding correlation based on time domain pilots
C: sliding correlation based on time domain pilot signals in cyclic prefix
D: joint detection with multi-antennas
E: energy detection
Slide 10
Huawei
July 2006
doc.: IEEE 802.22-06/0127r2
Conclusion
• Several detection schemes based on features of DVB-T
signals are suggested.
Submission
Slide 11
Huawei