MICRO-MODEM RELIABILITY SOLUTION FOR NOC COMMUNICATIONS

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MICRO-MODEM RELIABILITY SOLUTION FOR NOC
COMMUNICATIONS
Technion Israel Institute of Technology

• Arkadiy Morgenshtein, Evgeny Bolotin, Israel
  Cidon, Avinoam Kolodny, Ran Ginosar

QNoC Research Group, Electrical Engineering
Department Technion Israel Institute of
Technology Haifa, Israel
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Outline

• Networks-on-Chip (NoC)
• Communication Environment
• Motivation
• Micro-Modem Architecture
• Components of Micro-Modem
• Discussion

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Networks-on-Chip (NoC)

• NoC characteristics
• Packets-based data routing
• Modules connected by routers network
• Design modularity, various QoS levels
• Physical layer of NoC
• Submicron technologies
• Compact implementation
• Reliability challenges

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Signal Integrity Parameter Uncertainty

• Coupling capacitances
• QoS levels are physically adjacent
• Various activity factors
• Various frequency and packet sizes

interferences
wire delay
noise

• Device properties variations
• Nanoscale CMOS
• Threshold voltage variations
• Supply voltage variations

IR loss
leakage

• Temperature variations
• Activity and power variations in NoC
• Wire delays
• Noise
• IR losses
• Leakage

propagation delay
current drive
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Motivation

• Reliable data transportation
• Techniques for noise immunity
• Techniques for interference immunity
• Error identification and correction

interferences
wire delay
noise
IR loss
leakage
propagation delay
current drive
Modem!
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Modem in OSI Model of NoC
Application layer
Presentation layer
Session layer
Transport layer
Network layer
Data link layer
Physical layer
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Micro-Modem Architecture
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Components of Micro-Modem

• INPUT BUFFER
• Can be embedded in the Router
• Stores the packet for further parallel
  processing
• Requires high-performance compact memory cells

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Components of Micro-Modem

• ERROR CORRECTION
• 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

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Components of Micro-Modem

• SYNCHRONIZATION
• Clock recovery using 8x10 encoding
• Skew reduction between clock and data
• - start/stop synch series for clock
  initiation
• - ack/req signals for GALS structures
• Sequence numbers for packets ordering and
  detection of lost packets

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Components of Micro-Modem

• INTERFERENCE REDUCTION
• Encoding / Processing for reduced crosstalk and
  ISI
• Interleaving for reduced potential differences
  in wires with opposite signals

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Components of Micro-Modem

• PARALLEL-TO-SERIAL CONVERTER
• Core device in serial data transportation
• Has to be ultra-high speed to compensate the
  loss of parallelism (scaling)
• Has to be compact and low-power
• Has to be designed for various lane widths
  scenarios, or as a generic unit

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Components of Micro-Modem

• MODULATION
• Low voltage differential signaling (LVDS)
• - Low-swing signaling
• - High noise and ISI immunity
• Multiplexing techniques

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Components of Micro-Modem

• LINK INTERFACE
• Conditioning and buffering of the signal as it
• enters the wire
• Swing restoration
• Cascaded buffers for interconnect
• Fan-out drivers

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Application of Micro-Modem
Application of Micro-Modem can be function of
noise and inter-system distance
Possible µModem application types
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Application of Micro-Modem
Point-to-Point
End-to-End
Mid-Point
High noise Parallel links High Latency High
Power High Area
Low noise Serial links Low Latency Low Power Low
Area
Medium . . . .
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Preliminary Designs
32-bit Micro-Modem in 0.25 µm technology
210x90um µModem Transmitter for Router
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Questions?