25 March 2015 9:02:16 AM
Twitter | LinkedIn | Facebook | Reddit
Anyone attending OFC 2015 knows there is a LOT of material and not everything may apply to their respective interest or work product.
However, it is hard to ignore the importance of optics and the role it plays in both the current Mobile Fronthaul/Backhaul Transport and more importantly Next-Generation Mobile Fronthaul for 4.5G (2020) and 5G (2025).
Monday’s workshop, M2J - Next-Generation Mobile Fronthaul, with seven presentations, was full of these “hidden gems,” from my perspective. Certain facts and revelations are of particular treasure because they're based on the “reality of what is” versus “wishful thinking” of non-mobile infrastructure users of optical links. Many think "Ethernet-based" fiber optic protocols are suitable as is or only needs slight modifications to fully meet current and future Mobile Fronthaul requirements. Dr. Thomas Pfeiffer, Alcatel Lucent, correctly pointed out that a lot has to happen in order for this to happen within the IEEE 801.2 TSN (time-sensitive networking) task force and a newly formed IEEE 1904.3 Radio over Ethernet workgroup. The only problem is that the Common Public Radio Interface or CPRI Specification is what fully defines and sets Mobile Fronthaul requirements. CPRI cannot be adapted to fit Ethernet, rather it’s the other way round, Ethernet needs to be adapted to fit CPRI and Mobile Fronthaul.
Looking ahead, if the IEEE 1904.3 Access Networks Working Group is able to solve fundamental issues without breaking backward Ethernet compatibility, its resulting specification might come out in 2017. This means CPRI is "the Mobile Fronthaul" protocol until then. Other very interesting alternatives to CPRI were presented in this “hidden gem” OFC session but, they too have significant technical challenges to overcome. For example Radio over Fiber (RoF) looks really good on paper but, it doesn't have the capability to deliver command and control packets to the remote Radio head. This issue has already led to suppliers asking for dual fiber optic channels to add this critically important functionality. Other issues brought up in the session include IQ data compression and the fact that CPRI v6.1 specified data rates are at 12.1G, and not the more desirable 2.5G per-radio.
This OFC 2015 Session is bound to spur discussions in the optical fiber industry so wonderfully represented here at the LA Convention Center.
Contributed by Cary Snyder: Principal Analyst at EJL Wireless Research USA, and Consulting Engineer at Sarokal Test Systems Oy, Finland.
M2J - Next-Generation Mobile Fronthaul,
Presenter: Jun Shan Wey, LightNotes Consulting, USA
(click on each slide to view larger)