& cplSiteName &

Fujitsu Labs Develops 56G Receiver Circuit for Server Comms

Light Reading
News Wire Feed
Light Reading
6/13/2014
50%
50%

KAWASAKI, Japan -- Fujitsu Laboratories Ltd. today announced the development of a receiver circuit capable of receiving communications at 56 Gbps. This marks the world's fastest data communications between CPUs equipped in next-generation servers.

In recent years, raising data-processing speeds in servers has meant increasing CPU performance, together with boosting the speed of data communications between chips, such as CPUs. However, one obstacle to this has been improving the performance of the circuits that correct degraded waveforms in incoming signals.

Fujitsu Laboratories has used a new "look-ahead" architecture in the circuit that compensates for quality degradation in incoming signals, parallelizing the processing and increasing the operating frequency for the circuit in order to double its speed.

This technology holds the promise of increasing the performance of next-generation servers and supercomputers.

Details of this technology are being presented at the 2014 Symposia on VLSI Technology and Circuits, opening June 9 in Hawaii (VLSI Circuits Presentation 11-2).

In order to enhance the performance of datacenters underpinning the spread of cloud computing in recent years, a need has arisen for servers that process data faster. While this can be achieved partly through faster CPUs, large-scale systems connecting many CPUs are also being built, and the amount of data transmitted, either within the same CPU-equipped chassis or across separate chassis, is growing dramatically. To cope with these volumes, data communication speeds in the current generation of servers is increasing from a few gigabits per second today to ten or more gigabits per second. Because it is anticipated that data processing volumes will continue to experience explosive growth, however, for the next generation of high-performance servers, the goal is to double current levels to 56 Gbps. Furthermore, the Optical Internetworking Forum (OIF) is moving forward on the standardization of 56 Gbps for the optical modules used for optical transmission between chassis.

An effective way to speed up the receiver circuit is to improve the processing performance of the decision feedback equalizer (DFE) circuit that compensates for the degraded input-signal waveform (Figure 2).The principle behind DFE is to correct the input signal based on the bit-value of the previous bit and to emphasize changes in the input signal, but the actual circuit design works by choosing between two predefined corrected candidates. If the previous bit value was a 0, the correction process would apply a positive correction to the input signal (additive) to emphasize the change from 0 to 1. If the previous bit value was 1, it would apply a negative correction to the input signal (subtractive) to emphasize the change from 1 to 0. If another 0 was received, the positive compensation would increase the signal level, but not to such a level as would create a problem for the 1/0 decision circuit.

In ordinary circuit designs that run at 56 Gbps, there are 16 DFE circuits coupled together. Using 4 DFE circuits as an example, they run at 1/4th the actual frequency. So for 28-Gbps communications rates, 1/4th of that is 142 picoseconds, and four bits-worth of compensation can be applied during that interval. But at 56 Gbps, 1/4th of that speed amounts to 71 picoseconds, during which time only 2 bits-worth of compensation can be applied, resulting in timing errors (Figure 3).

Fujitsu Laboratories took a new approach, a "look-ahead" method that can be implemented as a parallel process, pre-calculating two candidates based on the selection result for the previous bit, and simultaneously deciding the value of the previous bit and the current bit after deciding the value of the bit two bits previous. This shortens calculation times, resulting in a receiver circuit that can operate at 56 Gbps (Figure 4).

Features of the new technology are as follows:

1. Look-ahead compensation process

In the existing method, the result of the previous bit's selection circuit (A) is implemented by a circuit combining the result of the selection circuit for the bit two bits previous (B) and the input signal for the selection circuit one bit previous (+/- compensation data) (C). In the look-ahead method, the input signal for the selection circuit one bit previous (+/- compensation data) (D) and the input signal for the selection circuit of the current bit (+/- compensation data) (E) are combined using a look-ahead circuit, and candidates for the selection circuit are pre-computed. Doing this relies on only the result from the selection circuit for the bit two bits previous, without using the result from the selection circuit for the bit one bit previous, while functioning essentially the same as the existing method.

2. Parallelized look-ahead processing using a hold circuit

Multiple look-ahead circuits that apply DFE one bit at a time can operate independently (Figure 5). Fujitsu Laboratories inserted a hold circuit between the selection circuit and look-ahead circuit, with the input and output of each hold circuit being synchronized, making it possible to parallelize these processes.

Because the calculation time for the look-ahead circuit is roughly the same as the selection time for the selector, overall calculation time is dependent on the number of selectors deciding based on data from two bits previous, so in a four-bit structure, that would be two. Running at 1/4th of 56 Gbps allows computations to be safely completed within 71 picoseconds. This makes it possible to receive data at 56 Gbps, doubling existing communications speeds.

This technology makes it possible to increase bandwidth of communications between CPUs in future servers and supercomputers, even if CPU performance doubles, without increasing pin counts, and will contribute to increased performance in large-scale systems where numerous CPUs are interconnected.

In addition, it complies with standards for optical-module communications, and compared to the 400-Gbps Ethernet in OIF-CEI-28G optical-module communications, the number of circuits running in parallel (number of lanes) can be halved, allowing for smaller optical modules running on less power, and higher system performance.

Fujitsu Laboratories plans to apply this technology to the interfaces of CPUs and optical modules, with the goal of a practical implementation in fiscal 2016. The company is also considering applications to next-generation servers, supercomputers, and other products.

Fujitsu Laboratories Ltd.

(0)  | 
Comment  | 
Print  | 
Newest First  |  Oldest First  |  Threaded View        ADD A COMMENT
Light Reading’s Upskill U is a FREE, interactive, online educational resource that delivers must-have education on themes that relate to the overall business transformation taking place in the communications industry.
NEXT COURSE
Wednesday, September 14, 1:00PM EDT
What Is Agile?
Kent J. McDonald, Product Owner, Agile Alliance
UPCOMING COURSE SCHEDULE
Friday, September 16, 1:00PM EDT
How to Implement Agile
Alan Bateman, Director, Agile Transformation
Wednesday, September 21, 1:00PM EDT
What Is DevOps?
Colin Kincaid, CTO, Service Provider, Cisco
Friday, September 23, 1:00PM EDT
How to Implement DevOps
,
in association with:
From The Founder
Light Reading today starts a new voyage as part of a larger Enterprise.
Flash Poll
Live Streaming Video
Charting the CSP's Future
Six different communications service providers join to debate their visions of the future CSP, following a landmark presentation from AT&T on its massive virtualization efforts and a look back on where the telecom industry has been and where it's going from two industry veterans.
Between the CEOs
CEO Chat: UXP Systems' Gemini Waghmare

8|26|16   |     |   (0) comments


Light Reading CEO Steve Saunders and UXP Systems CEO Gemini Waghmare discuss the strategic importance of digital identity for operators in the midst of transformation.
LRTV Custom TV
F5 Virtual Network Function Integrations With Partner Orchestration Platform

8|24|16   |   6:38   |   (0) comments


F5's Kishore Patnam, product manager for F5's service provider solutions, discusses why service providers are moving towards virtualization and how his clients are utilizing F5's solutions.
Between the CEOs
CEO Chat: Intel's Alexis Black Bjorlin

8|17|16   |   06:23   |   (0) comments


Join us for an in-depth interview between Steve Saunders of Light Reading and Alexis Black Bjorlin of Intel as they discuss the release of the company's Silicon Photonics platform, its performance, long-term prospects, customer expectations and much more.
Telecom Innovators Video Showcase
Accelerating Telecom Digital Transformation With Nominum DNS

8|1|16   |   12:04   |   (0) comments


Light Reading's Steve Saunders gets an update from Nominum CEO Gary Messiana on how his company is helping carriers on the digital transformation journey.
LRTV Custom TV
Reinventing Operations for a Virtual, Software-Defined World

7|28|16   |   5:23   |   (0) comments


Heavy Reading Senior Analyst Jim Hodges speaks with Accenture's Larry Socher and Matt Anderson about what service providers must do to transform their business to get the benefits of SDN and NFV including: leveraging DevOps, introducing real-time OSS and implementing analytics.
Women in Comms Introduction Videos
Fujitsu Sales Leader Shares Lessons Learned

7|27|16   |   5:12   |   (1) comment


As Fujitsu's only female sales leader, Annie Bogue knows the importance of asking for what you want, being flexible (she's been relocated five times), keeping a meticulous calendar, 'leaning in,' working harder than everyone else around you, being aware and more.
Telecom Innovators Video Showcase
VeEX Test & Measurement Solutions

7|25|16   |   08:57   |   (0) comments


Cyrille Morelle, president and CEO of VeEX Inc., talks test and measurement with Light Reading's Steve Saunders at BCE 2016. This includes innovative products such as VeSion Cloud-Based platform for network monitoring; MTTplus Modular Test platform for Access, Business, Carrier Ethernet, Transport and Core services; and OPX-BOX+ for Fiber Optics.
LRTV Custom TV
VeEX: Live From BCE 2016

7|25|16   |   03:20   |   (0) comments


VeEX's Senior Director of Business Development, Perry Romano, explains how VeEX provides tools to help install, maintain, monitor and manage network infrastructure efficiently and effectively. The portfolio of products on display include the RXT-6000, MTTplus and TX300s.
LRTV Custom TV
Real-Time Telemetry & Analytics for Intelligent SDN Orchestration

7|25|16   |   03:09   |   (0) comments


Packet Design CEO Scott Sherwood discusses how real-time network telemetry and analytics are enabling a new breed of SDN orchestration applications.
From the Founder
The Russo Report: Driving Disruption

7|25|16   |   07:44   |   (2) comments


In the first episode of a four-part series, Light Reading Founder and CEO Steve Saunders and Calix President and CEO Carl Russo drive around town discussing the disruptive mega-changes in the communications industry and where hope lies for service providers to meet the escalating demands of the cloud.
LRTV Custom TV
NetScout: Maximizing Enterprise Cloud for Digital Transformation

7|20|16   |   04:53   |   (0) comments


Light Reading Editor Mitch Wagner talks to NetScout CMO Jim McNiel about maximizing the benefits of enterprise cloud and digital transformation while minimizing potential pitfalls with a proper monitoring and instrumentation strategy.
Women in Comms Introduction Videos
Ciena's VP Offers a Career Crash Course

7|20|16   |   4:14   |   (2) comments


How did Ciena's Vice President of Sales, Angela Finn, carve out her career path? Simple, she tells WiC. She stayed true to her company, customers and principles. She shares her advice for women on how to be authentic and credible, as well as for companies that want to make a real change to their culture and practices.
Upcoming Live Events
September 13-14, 2016, The Curtis Hotel, Denver, CO
November 3, 2016, The Montcalm Marble Arch, London
November 30, 2016, The Westin Times Square, New York City
December 1, 2016, The Westin Times Square, New York, NY
December 6-8, 2016, The Westin Excelsior, Rome
May 16-17, 2017, Austin Convention Center, Austin, TX
All Upcoming Live Events
Infographics
Hot Topics
Google Fiber Can't Be Called a Failure
Carol Wilson, Editor-at-large, 8/26/2016
FirstNet: A Billion-Dollar Boondoggle?
Dan Jones, Mobile Editor, 8/26/2016
WiCipedia: Should Men Be Included? & Olympians Face Discrimination
Eryn Leavens, Special Features & Copy Editor, 8/26/2016
How the Padres Hit an IoT Home Run
Mitch Wagner, West Coast Bureau Chief, Light Reading, 8/25/2016
Google Fiber Downsizing Not Confirmed
Mari Silbey, Senior Editor, Cable/Video, 8/25/2016
Like Us on Facebook
Twitter Feed
BETWEEN THE CEOs - Executive Interviews
Light Reading CEO Steve Saunders and UXP Systems CEO Gemini Waghmare discuss the strategic importance of digital identity for operators in the midst of transformation.
Join us for an in-depth interview between Steve Saunders of Light Reading and Alexis Black Bjorlin of Intel as they discuss the release of the company's Silicon Photonics platform, its performance, long-term prospects, customer expectations and much more.
Animals with Phones
Live Digital Audio

Bridging the tech skills gap is a major challenge for service providers and suppliers alike today – and the challenge is two-fold when it comes to increasing the number of women in the comms space. Level 3 Communications has made it a priority to overcome both challenges by implementing several unique programs focused on building the right candidates from within – in addition to filling the funnel by supporting STEM and other education programs. During this radio show, you’ll learn about these programs from Mary Beth McGrath, SVP of Global Talent Management at Level 3, and the best ways to bridge your own skills gap so that you are motivated and equipped for change. Plus you’ll have the chance to ask Mary Beth your questions live on the air.