Mellanox Showcases 100G CPRI Transceiver, Optical Engines and Silicon Photonics Wafers at ECOC and CIOE


With networks and data centers all going wireless and into the clouds, Mellanox is announcing the volume production of a new 96G/100Gb/s SR4 multi-mode 4-channel transceiver with one of the top worldwide wireless infrastructure suppliers. The solution features an extended temperature range for supporting outside plant optical front haul links in the Fifth Generation of Mobile Networks, and supports dual line rates as well as both protocols of Ethernet and CPRI or Common Public Radio Interface which are used primarily between remote radio heads (RRH) and base band units (BBU).

Solution Highlights:

  • Based on 100G SR4 Ethernet multi-mode transceiver shipping in high volume
  • Employs Mellanox-designed transceiver ICs
  • Boasting dual line rates and protocols of 24.3G CPRI and 25.8G Ethernet
  • Offers an extended temperature range
  • Available now in volume shipments

“Front haul” links are named thus because the traffic is carried from the cellular antennas to base station controllers, which is at the front of the wireless network. Since wireless antennas are generally found in an outside plant environment, the SR4 CPRI transceiver has a wider temperature rating.

With trials beginning in China and around the world in late 2018, and with full deployments estimated to begin in 2019, this new transceiver is suitable for short-reach outside plant optical transmission between remote radio head (RRH) and base band units (BBU). Multi-mode transceivers create the lowest cost optical links and can be used both inside base stations as well as for short reaches up to 100 meters running up to the top of antenna structures. More expensive single-mode transceivers are used for longer reaches.

CPRI/fiber links are rapidly replacing microware systems and are positioned to play well with Centralized Radio Access Networks (C-RAN) and software-defined-everything in the future.

What’s Driving the Move to 5G?

All of these demand factors are coming at Internet systems all at once which is driving data traffic through the roof and is at the root of multi-acre-sized hyperscale data centers which seem to be popping up everywhere:

  • IoT: Internet connections are expanding and linking nearly everything Internet of Things (IoT) and poses to link everything from power and water grids, autos, homes, appliances, tools, pets, watches to smart water bottles!
  • UHDTV: 4K and 8K resolution HDTV is a reality now. PCs, HDTVs, even cell phones support 4K video today. Moscow 2018 and Japan 2020 Olympics with 8K video will drive network demand. 4K offers not only four times the pixel resolution of standard 2K HDTV but also has many advance features as well.
  • 4K cellphone photos – already people are texting 4K cat photos and videos!
  • Video Streaming – TV and Movies; video calls; drones with 4K video cameras
  • Internet connected autos
  • Virtual and augmented reality; real-time gaming
  • Everything available from anywhere – on cellphones, pads and PCs


When Will 5G Be Relevant?

The bottom line is that carriers and everyone in the content supply chain knows there will be big money in 5G and new revenue streams from new 5G applications and capabilities. The pressure is on to accelerate deployments and so are the standards battles for alternative approaches poised to delay everything.

The new 5th generation wireless network scheduled to come on line beginning in 2019 will provide a much faster and efficient connection to cellular wireless equipment. Offering more than just a faster line rate, 5G will improve the connection quality and range. Preliminary tests have shown data rates as high as 10 Gb/s to the cell phone which reflects an application game changer!

Mellanox 100G SR4 CPRI Transceiver Features

The newly announced 100Gb/s SR4 transceiver for wireless networks has its genesis in the highly popular, standard temperature version of the 100G SR4 for hyperscale, Web 2.0 Cloud and enterprise data centers. Unique features include:

  • 4-channels of 24.33G or 25.78G supporting CPRI 97G or Ethernet 100G
  • Standard QSFP28 form-factor compliant to the SFF-8655
  • MPO multi-mode optical connector, 8-fibers
  • IEEE CAUI-4 electrical specification
  • Selectable Tx and Rx retiming (CDRs)
  • Supports digital diagnostic monitoring of supply voltage, temperature, transmit/receive power, and laser bias.
  • Boasts ISFU – In-Service-Firmware-Upgrade a capability that enables upgrading the transceiver firmware while running traffic in addition to module being hot pluggable
  • Tested extensively in Mellanox switching systems
  • Bit Error Ratio (BER) better than 1E-15, about 1,000 times fewer bit errors than competitor’s products

The CPRI SR4 transceiver is designed using Mellanox’s own designed transceiver control ICs for VCSEL laser drivers and TIA receiver amplifiers. The close matching of driver and receiver electronics with optics enables the SR4 to boast a 1.5W typical power consumption without retiming and 2.2W with retiming – some of the lowest power ratings in the industry. With power budgets skyrocketing, every Watt saved at the component level translates into several Watts of system cooling and related power consumption driving fans, and AC equipment. Powering remotely located equipment is very expensive.

Besides Mellanox designing and building an entire transceiver, Mellanox also builds switching systems, and the transceivers are tested in real switching systems such as the 32-port 100G SN2700 switch, and not simulated on a test bench as most competitors do. By building our own electronics and transceivers, as well as testing in real systems, this guarantees they will work out of the box and at a bit error ratio (BER) of 1E-15. This is about 1,000 fewer bit errors than the IEEE industry standard of 5E-5 and using forward error correction (FEC) to achieve 1E-12. The additional BER rating enables a wider margin for components in difficult operating conditions of outside plant.

Three Converging Factors Changing CPRI Networks:

  • Line Rates Converge: CPRI line rates have not been aligned with the Ethernet rates due to historical reasons when long reach coaxial copper wires were used. Rates evolved from 3G, 6G, 12G and now to 24.33G and is now very close to the Ethernet 25.78G rate.
  • Adoption of Four-Channels: Most of the CPRI networks use single-channel SFP transceivers but the CPRI committee is now considering using the 4-channel to increase port density to handle the huge influx of traffic, simpler fiber management and one optical connector for four instead of only one channel.
  • QSFP Form-factor: 3 or 97.2G too close to the Ethernet 100G rates to ignore. Hence, the CPRI committee has considered using the 4x25G (100G) QSFP28 form-factor standard Ethernet transceivers now available in huge volumes.

These factors lead to CPRI network builders adopting standard 4x25G (100G) QSFP28 Ethernet transceivers already being produced in huge unit volumes which should enable lower network costs and faster deployments. Dual rate capability makes it a double hit.

Bottom line:

While standards, software architectures, hardware architecture of central office-based or distributed BBU, C-RAN or not, and buzz-words are all in a high state of flux, a few things are clear:

  • A hard fiber link is needed from the antennas to base stations no matter what else happens beyond that in “software land”. Fiber has the bandwidth and the long reach capabilities. The days of microwave and copper coax wire are over.
  • Multi-mode optics is clearly the least expensive solution, making the 100G SR4 dual rate transceivers a perfect match going forward over the short reach.
  • It is also clear that both CPRI and Ethernet will play side by side roles in advanced 5G networks due to the unique capabilities of each protocol as well as the high unit volume cost advantages of Ethernet versus specialized CPRI transceivers.

Mellanox’s dual protocol, dual rate SR4 transceiver using Mellanox designed ICs, manufactured and tested by Mellanox in Mellanox systems and optimized for very low-power consumption and low bit error rates makes it a perfect low-cost choice for CPRI/Ethernet networks.


Supporting Resources:

LinkX is the Mellanox trademark and name for its cables and transceivers product line


About Brad Smith

Brad is the Director of Marketing at Mellanox, based in Silicon Valley for the LinkX cables and transceivers business focusing on hyperscale, Web 2.0, enterprise, storage and telco markets. Recently, Brad was Product Line Manager for Intel’s Silicon Photonics group for CWDM4/CLR4 and QSFP28 product lines and ran the 100G CLR4 Alliance. Director of Marketing & BusDev at OpSIS MPW Silicon Photonics foundry. President/COO of LuxSonar Semiconductors ( Cirrus Logic) and co-founder & Director of Product Marketing of NexGen, a X86-compatible CPU company sold to AMD - now the X86 product line. Brad also has ~15 years in technology market research as Vice president of the Computer Systems group at Dataquest/Gartner; VP/Chief Analyst at RHK and Light Counting networking research firms. Brad started his career at Digital Equipment near Boston with the VAX 11/780 and has served as CEO, president/COO and on the board-of-directors of three start-up companies. Brad has a BSEE degree from the University of Massachusetts; MBA from University of Phoenix and holds 2 optical patents

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