Transcript NoC presentation

QNoC
Research
Technion – Israel Institute of Technology
Group
MICRO-MODEM
RELIABILITY SOLUTION FOR NOC
COMMUNICATIONS
Arkadiy Morgenshtein, Evgeny Bolotin, Israel Cidon, Avinoam Kolodny, Ran Ginosar
QNoC Research Group, Electrical Engineering Department
Technion – Israel Institute of Technology
Haifa, Israel
Outline
• Networks-on-Chip (NoC)
• Communication Environment
• Motivation
• Micro-Modem Architecture
• Components of Micro-Modem
• Discussion
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Networks-on-Chip (NoC)
NoC characteristics
• Packets-based data routing
• Modules connected by routers network
• Design modularity, various QoS levels
Router
Physical layer of NoC
Module
• Submicron technologies
• Compact implementation
• Reliability challenges
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Signal Integrity & Parameter
Uncertainty
Coupling capacitances
• QoS levels are physically adjacent
• Various activity factors
• Various frequency and packet sizes
!
Device properties variations
Router
• Nanoscale CMOS
• Threshold voltage variations
• Supply voltage variations
Aggressive
Temperature
variations
Environment
•
•
•
•
•
4
Module
Activity and power variations in NoC
Wire delays
Noise
IR losses
Leakage
Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Motivation
Reliable data transportation
• Techniques for noise immunity
• Techniques for interference immunity
• Error identification and correction
Router
Uniform Communication Interface
• Simple
• Compact
• Low-power
• Scalable
• Reusable
• Adaptive
Module
Modem!
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Modem in OSI Model of NoC
Router
Modem
Modem
Presentation layer
Modem
Application layer
Session layer
Transport layer
Modem
Network layer
Data link layer
Physical layer
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Micro-Modem Architecture
Router
n
µModem
µModem
µModem
Router
Input
Buffer
Error Correction
Synchronization
µ Modem
ISI reduction
m
Parallel-to-Serial Converter
µModem
µModem
Router
µModem
Modulation
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Micro-Modem – Reliability Solution for NoC Communications
Interconnect
µ Modem
Link Interface
ICECS 2004
Components of Micro-Modem
Router
INPUT BUFFER
n
Input
Buffer
• Can be embedded in the Router
• Stores the packet for further parallel processing
• Requires high-performance compact memory cells
Error Correction
Synchronization
ISI reduction
m
Parallel-to-Serial Converter
Modulation
Link Interface
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Components of Micro-Modem
Router
ERROR CORRECTION
n
Input
Buffer
• Implements error detection and correction
• Can be also used for restoration of bits lost
- low-swing effects in low-area circuit designs
- voltage drop in resistive wires
- low signal integrity due to ISI, cross-talk and noise
• Has to be implemented using robust full-swing circuits
Error Correction
Synchronization
ISI reduction
m
Parallel-to-Serial Converter
Modulation
Link Interface
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Components of Micro-Modem
Router
SYNCHRONIZATION
n
Input
Buffer
• Clock recovery using 8x10 encoding
• Skew reduction between clock and data:
- start/stop synch series for clock initiation
- ack/req signals for GALS structures
Error Correction
Synchronization
ISI reduction
m
Parallel-to-Serial Converter
• Sequence numbers for packets ordering and
detection of lost packets
Modulation
Link Interface
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Components of Micro-Modem
Router
n
INTERFERENCE REDUCTION
Input
Buffer
• Encoding / Processing for reduced crosstalk and ISI
• Interleaving for reduced potential differences in wires
with opposite signals
Error Correction
Synchronization
ISI reduction
m
Parallel-to-Serial Converter
A
A
A
int
Modulation
A
Link Interface
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Components of Micro-Modem
Router
PARALLEL-TO-SERIAL CONVERTER
n
Input
Buffer
• Core device in serial data transportation
• Has to be ultra-high speed to compensate the
loss of parallelism (scaling)
Error Correction
Synchronization
ISI reduction
m
• Has to be compact and low-power
• Has to be designed for various lane widths
scenarios, or as a generic unit
Parallel-to-Serial Converter
Modulation
Link Interface
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Components of Micro-Modem
Router
n
MODULATION
Input
Buffer
• Low voltage differential signaling (LVDS)
- Low-swing signaling
- High noise and ISI immunity
Error Correction
Synchronization
ISI reduction
• Multiplexing techniques
m
Parallel-to-Serial Converter
Modulation
Link Interface
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Components of Micro-Modem
Router
LINK INTERFACE
n
Input
Buffer
• Conditioning and buffering of the signal as it
enters the wire
Error Correction
Synchronization
• Swing restoration
ISI reduction
m
• Cascaded buffers for interconnect
Parallel-to-Serial Converter
Modulation
• Fan-out drivers
Link Interface
Interconnect
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Application of Micro-Modem
Application of Micro-Modem can be function of noise and inter-system distance
Noise
Level
Mid-Points
Point-to-Point
la
te
n
cy
high
low
End-to-End
short
Mid-Points
long
Transport
Range
Possible µModem application types
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Application of Micro-Modem
Point-to-Point
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Mid-Point
End-to-End
High noise
Medium
Low noise
Parallel links
.
Serial links
High Latency
.
Low Latency
High Power
.
Low Power
High Area
.
Low Area
Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Preliminary Designs
32-bit Micro-Modem in 0.25 µm technology
210x90um µModem Transmitter for Router
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Micro-Modem – Reliability Solution for NoC Communications
ICECS 2004
Questions?
Router
n
µModem
µModem
µModem
Router
Input
Buffer
Error Correction
Synchronization
µ Modem
ISI reduction
m
Parallel-to-Serial Converter
µModem
µModem
Router
µModem
Modulation
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Micro-Modem – Reliability Solution for NoC Communications
Interconnect
µ Modem
Link Interface
ICECS 2004