performance evaluation of coded uwb-ir on multipath fading
TRANSCRIPT
![Page 1: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/1.jpg)
1
Performance Evaluation of Coded Performance Evaluation of Coded UWBUWB--IR on IR on MultipathMultipath Fading ChannelsFading Channels
Michal PietrzykJos Weber
March 3, 2005
Wireless and Mobile Communications GroupDelft University of Technology
The Netherlands
![Page 2: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/2.jpg)
2
Overview of Presentation
• What is Ultra-wideband (UWB)?• Regulatory Issues• Unique Properties of UWB• UWB vs. Other Technologies• Potential Applications of UWB• Research Challenges• Research Problem• General Coding-Modulation • UWB-IR Receiver Model• UWB Channel Model• Performance Evaluation• Summary
![Page 3: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/3.jpg)
3
What is Ultra-wideband (UWB) ?
• UWB technology is a generic term describing radio systems having very large bandwidth.
• Two definitions under consideration by the FCC: - fractional bandwidth of a radio signal becomes 20% or more of the signal’s center frequency
is the upper 10 dB and is the lower 10 dB cut-off frequency of the signal spectrum.
- RF bandwidth of the signal is greater than 0.5 GHz.
20.02 ≥⎟⎟⎠
⎞⎜⎜⎝
⎛+−
=LH
LHffffB
Hf Lf
![Page 4: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/4.jpg)
4
Regulatory Issues
802.11bBand
802.11aBand
Emission limits for UWB indoor communication systems set by the FCC.
![Page 5: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/5.jpg)
5
Narrowband vs. Different UWB Approaches
Narrowband Systems
UWBUWB –IR
UWB-FMUWB-OFDM
Time Frequency
Time Frequency
![Page 6: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/6.jpg)
6
Unique Properties of UWB
• High data rate capability for communications• Fine range resolution capability• Multipath immunity• Extremely difficult to intercept (LPD/I)• Suitable for ad hoc resource allocation/selection• Common architecture for communications, radar and
positioning (software re-definable)• Low power consumption• Low cost
![Page 7: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/7.jpg)
7
UWB vs. Other Technologies (1)
0.1 1 10 100 1000
0.1
1
10
100
1000
0.01
802.11a/b
Bluetooth
UWB
Mbits/s
Range(m)
10000
GSM
UMTS
Data rate
![Page 8: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/8.jpg)
8
UWB vs. Other Technologies (2)
0.1 1 10 100 1000
0.1
1
10
100
1000
0.01
Cellular
GPS
Range(m)
10000
10000
UWB
BluetoothWLAN
(cell ID)
Accuracy(m)
![Page 9: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/9.jpg)
9
Potential Applications of UWB (1)
• Collision avoidance radars• Tags (Intelligent Transportation Systems, electronic
signs)• Precision geolocation systems• Surveillance systems• Tactical handheld & network LPD/I radios• Medical imaging• High Speed WPANs and WLANs
Example use of UWB through-wall surveillance radar. Courtesy of Time Domain Inc.
Example use of collision avoidance radar.
![Page 10: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/10.jpg)
10
Potential Applications of UWB (2)
Broadband
wired &wireless
wired &wireless
wired &wireless
Long range deliverywired & wireless
wired &wireless
wired &wireless
Local high data rate delivery
Source: Communication and Interconnect Technology Lab., Intel Research and Development
![Page 11: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/11.jpg)
11
Research ChallengesInterference issues pose restrictions on the maximum data rate that can be supported. One way to overcome the destructive effects of ISI and IFI and simultaneously maintaining a certain performance level is to apply error correction coding.
An error correction coding scheme dedicated for UWB-IR communications should- be of low complexity- be scalable- provide reasonable BER performance- introduce small delay.
Potential candidates include- superorthogonal convolutional (SOC) coding- turbo superorthogonal convolutional (TSOC) coding- TCH (Tomlinson, Cercas, and Hughes) coding.
There are methods for further BER performance improvements like e.g.- proposed interleaved coding-modulation (ICM) technique- polarity randomization (PR).
![Page 12: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/12.jpg)
12
Research Problem
The UWB-IR system model incorporates:
- differential autocorrelation receiver
- realistic channel model proposed by the IEEE (802.15.3a)
- real antennas’ characteristics- distortions introduced by amplifiers, and filtersmodeled by a Chebyshev filter- frame repetition or superorthogonal convolutionalcoding as methods of protection against transmission errors.
What is the performance of a feasible UWB-IR system with error correction coding in a severe multipath environment ?
![Page 13: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/13.jpg)
13
General Coding-Modulation Scheme
time
time
time
Tf
Tb
Tw
LEVEL
PACKETS
INFORMATIONBITS
CODESYMBOLS
FRAMES
PULSES
k
n
1
Nf
Np
time
time
Ts
1
"ChannelCoding"
"FrameRepetition"
"PseudorandomAssignment"
Modulation
![Page 14: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/14.jpg)
14
UWB-IR Receiver Model
r(t)
τ r''(t-τ)
r''(t)r''(t-τ)
Viterbidecoder
> 0y(FR)
1
y(SOC)
n
1
1
H0
(FR)<
, H1
(FR)<
H0 1
(SOC)<
, H(SOC)<
BPF NLNA
ANTH1(f)
H2(f)
r'(t)
r''(t)∫τ
2τ
(⋅)dt
>
Fig. 1. The modeled UWB-IR receiver architecture.
Fig. 2. Superorthogonal convolutional encoder. Fig. 3. The Gaussian monocycle and the received waveform.
K stage shift register
K-2 Orthogonal BlockEncoder
+
Input 1 bit
2K-2Output
2K-2
symbolssymbols
![Page 15: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/15.jpg)
15
UWB Channel Model
0 50 100 150 200 250-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2Snapshot of channel impulse response for NLOS environment
t
h
0 20 40 60 80 100 120 140 160 180-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4Snapshot of channel impulse response for LOS environment
t
h
Fig. 4. Channel impulse response for the case of LOS environment.
Fig. 5. Channel impulse response for the case of NLOS environment.
Main parameters (LOS and NLOS):
a) RMS delay spread: 9 and 15 ns
b) Np_10dB: 7 and 35.
![Page 16: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/16.jpg)
16
UWB-IR System Parameters
![Page 17: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/17.jpg)
17
Performance Evaluation (1)
The upper bound on the bit error probability of the UWB-IR system with the SOC code is given by
For a Gaussian channel and a rectangular pulse shape we have
and [M. Pausini ‘04]
Processing gain is defined as
Free distance of the SOC code is
The lower bound on the bit error probability of the UWB-IR system with the SOC code is expressed as
where
Free distance of the FR scheme is
![Page 18: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/18.jpg)
18
Performance Evaluation (2)
4 6 8 10 12 14 1610
-4
10-3
10-2
10-1
Eb/No (dB)
BE
R
SOC, AWGNFR, AWGNSOC, LOSFR, LOSUpper and Lower Bound SOC, AWGN
Fig. 6. BER performance of the UWB-IR systems with SOC coding and FR for Nf = 8, Np = 6, K = 5 in AWGN and LOS environments.
4 6 8 10 12 14 1610-4
10-3
10-2
10-1
Eb/No (dB)
BE
R
SOC, AWGNFR, AWGN,SOC, NLOSFR, NLOSUpper and Lower Bound SOC, AWGN
Fig. 7. BER performance of the UWB-IR systems with SOC coding and FR for Nf = 8, Np = 6, K = 5 in AWGN and NLOS environments.
![Page 19: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/19.jpg)
19
Summary
Performance investigated with the use of - a realistic channel model- real antennas’ characteristics.
The BER performance evaluated by theoretical and numerical analyses.
2. SOC coding constitutes a good alternative to frame repetition without costs in any additional bandwidth expansion.
3. Complexity of a SOC decoder grows linearly with K making the SOC decoder feasible.
1. Novel coding-modulation scheme.
![Page 20: Performance Evaluation of Coded UWB-IR on Multipath Fading](https://reader030.vdocuments.us/reader030/viewer/2022012019/61686ebbd394e9041f6f8b81/html5/thumbnails/20.jpg)
20
Thank you