O-RAN Alliance Gives PON Brigade a 5G Fronthaul Boost

SAN DIEGO -- OFC 2019 -- The increasingly influential O-RAN Alliance has given the Passive Optical Network (PON) access network sector got a 5G boost by deciding to adopt PON technology as an option in fronthaul networks, according to an AT&T executive.

Speaking here today in a 5G symposium session, Kent McCammon, a lead member of Technical Staff at AT&T, said the O-RAN Alliance, which boasts many of the world's major Tier 1 operators as its members, voted unanimously at a meeting in Madrid on February 21 to adopt PON as an option for mobile fronthaul, the connection in a disaggregated radio access network (RAN) between centralized baseband controllers and remote standalone radio heads at cell sites.

The move should encourage the development of low-latency PON technologies by the vendor community conforming to "Cooperative Transport Interface" specifications being developed by the O-RAN members that will make PON options suitable for the operators' needs. "PON was not developed with low latency in mind," noted McCammon.

The O-RAN Alliance's move runs in parallel with a very similar development at the ITU, which has been working for some time on low-latency PON specifications: McCammon noted that there may be moves to align the terminology used by the groups, both of which count AT&T as an active member.

PON technologies have for some time been regarded as an option for fronthaul, though other options, including dark fiber and WDM, have been regarded as more suitable. Even with PON there is a broad range of options and flavors, from asymmetrical or symmetrical 10G PON to NG-PON2, the access technology being championed by Verizon.

Whichever way the O-RAN Alliance swings is likely to have an impact on vendor R&D plans and operator strategies as the industry group is becoming increasingly influential and attracting the participation of most (if not all) of the major players from the operator and vendor community: Huawei is the notable absentee from the vendors, while Ericsson only recently joined and with a limited remit.

Optical components firms such as NeoPhotonics and Source Photonics, and systems vendors such as Adtran, Calix, Huawei and Nokia, will no doubt be interested in how this O-RAN decision might impact fronthaul planning and technology requirements.

For more on the O-RAN Alliance, which aims to develop radio access network architectures based on open interfaces that enable multi-vendor deployments, see:

• DT's Choi Rages Against the RAN Machine
  
• White Box Doubts Keep Huawei on Outside of O-RAN Alliance
  
• Why Ericsson Is Joining the ORAN Alliance
  
• Open Conflict Over Open RAN
  
• AT&T, Nokia Team on O-RAN Code
  
• Open RAN, Open Interfaces
  
• TIP, ORAN Alliance Poised to Join Forces on Open RAN

— Ray Le Maistre, Editor-in-Chief, Light Reading