March 2004 10GBASE-T: A new proposal for improving PAM performance with OFDM Yuji Kasai, Eiichi Takahashi, Tetsuya Higuchi (National Institute of Advanced Industrial Science and Technology ) Masahiro Murakawa (Evolvable Systems Research Institute) Shinji Nishimura (Hitachi, Ltd.)
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10GBASE-T: A new proposal for improving PAM performance with OFDMgrouper.ieee.org/groups/802/3/an/public/mar04/higuchi_1... · 2004. 3. 10. · 2. OFDM Modulation on DSP DSP processing
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March 2004
10GBASE-T: A new proposal for improving PAM performance with OFDM
Yuji Kasai, Eiichi Takahashi, Tetsuya Higuchi(National Institute of Advanced Industrial Science and Technology )
Masahiro Murakawa(Evolvable Systems Research Institute)
Shinji Nishimura(Hitachi, Ltd.)
2
Supporters
• The Tokyo Electric Power Company, Inc.
• POWEREDCOM, Inc.
3
• OFDM signal transmission method applied to 10GBASE-T
• PAM-based frequency division multiplexing – 10-Gbps data transmission– 6.1-dB noise margin
• 100-m signal transmission with CAT-7 cable
Objectives
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1. Current 10GBASE-T proposals
+3 -3 -1-4 Noise Margin (dB)with 6 dB coding gain
0.5-2us
20
-
500
1000
4D-PAM8
192633 RequiredSNR (dB)
< 100 ns
2
625
1250
PAM-5
< 100 ns< 100 nsLatency
3-LaunchVoltage (Vp-p)
417312.5Bandwidth(MHz)
833625Symbol Rate(Mbps)
PAM-10PAM-20
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1. Issues with current proposals
6005004003002001000Freq. [MHz]
700 800
20
40
60
0
SNR [dB]
PAM20
PAM10
PAM5 Class-E 55m
Class-F 100m10
30
50
70
4D-PAM
6-dB coding gain included
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2. OFDM Technique for 10GBASE-T
● Orthogonal Frequency Division Multiplexing (OFDM)– Special form of multi-carrier modulation– High spectral efficiency – Less sensitive to inter-symbol interference
● 7 PAM signals transmitted over 7 frequency-nonselective channels
● Required frequency bandwidth: 547 MHz + pilot signal● Symbol rate: 156.25 MHz (=10GHz/(4chx16bit))● Low latency: < 100 ns
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OFDMSignal
f1-I
f1-Q
f2-I
f2-Q
f3-I
f3-Q
Data Signals
f1 f2 f3156.25MHz 312.5MHz 468.75MHz
546.88MHz0 Freq.
Spectrum
2. OFDM Technique
Σ
OFDM technique distributes the data over a number of carriers that are spaced apart at precise frequencies. This spacing provides the "orthogonality" which prevents the demodulators from seeing frequencies other than their own.
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2. Signaling in OFDM
01+12+23+3
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Data bits
3468.75 MHz (I,Q)0
51020
PAM Level
625 MHzpilot signal
312.5 MHz (I,Q)156.25 MHz (I,Q)Base signal
Carrier Frequency
Total 16 bitsI: In-phase, Q: Quadrature-phase
156.25 MHz
I Q
312.5 MHz
I Q
468.75 MHz
I Q
Frequency: Base signal
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2. SNR Margins
6005004003002001000Freq. [MHz]
700 800
20
40
60
0
SNR [dB]
(PAM20)
(PAM10)
(PAM3)
Class-E 55m
Class-F 100m10
30
50
70
(PAM5)
8dB
6dB
7dB
7dB
6-dB coding gain included
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DSP
2. Block Diagram
RJ45Hybrid
LineDriver
RxAmp.
AnalogFiltering
AnalogFiltering
DAC
ADC
OFDMDecoder
OFDMEncoder
Scrambler
De-scrambler
MACIF
ClockGeneratorClock
Detector
625MHz
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2. OFDM Modulation on DSP
● DSP processing on TX– 7 PAM signals (pi) are converted into 12 OFDM signals (xi,xpi,xni).– One symbol consists of 8 OFDM signals (xi).