Nokia unveils optical transport line for centralized radio access networks

Nokia has unveiled the 1830 Versatile WDM Module (VWM) family, a line of optical transport platforms designed to support centralized radio access network (C-RAN) architectures for mobile fronthaul applications.

A C-RAN separates baseband processing from RF equipment such as remote radio heads (RRHs); the processing is performed at a central location, rather than at each cell tower. The architecture promises faster broadband delivery, increased capacity, and lower opex.

Of course, this requires communications between the towers or other mobile access points and that central facility – specifically, WDM-based optical transmission, according to Hector Menendez, product marketing manager, IP/Optical Networks at Nokia, and Rob Levesque, product line manager, IP/Optical Networks. That's where the 1830 VWM portfolio comes in. The line includes five units:

1. The 1830 VWM Photonic Managed Unit (PMU), a WDM unit that, in its initial incarnation, will support nine wavelengths – 18 if two units are combined. A DWDM version of the PMU that will support 44 channels should be available later this year, according to Menendez.
2. The 1830 VWM Translation Line Unit (TLU), which translates grey optics, such as the output of CPRI optical transceivers, into colored wavelengths.
3. The 1830 VWM Optical Supervisory Unit (OSU), which provides OAM for end-to-end network monitoring.
4. The 1830 VWM TLU/PMU-4, a compact field unit that combines PMU and TLU functions for applications such as small cells.
5. The Site Monitoring Module, provides alarm monitoring based on user-defined inputs at cell-site locations with the ability to turn on/off appliances and devices.
   

The family works with all currently fielded versions of CPRI, say the Nokia sources. The translation function does not involve direct manipulation of the CPRI-formatted signals or the addition of frames. Thus, the CPRI signals arrive in their original form, Menendez says.

All elements of the 1830 VWM family with the exception of the TLU-PMU-4 and the Site Monitoring Module are currently available; the laggards will reach the market in the second quarter of this year, says Menendez. Nokia already has more than 30 customer engagements, including a few sales, surrounding the currently available units, he adds.

While some carriers are exploring copper-based approaches to C-RAN (see "BT examines G.fast for cloud RANs") and might be tempted to use microwave, Menendez says it's likely fiber-optic networks will provide the foundation for most such applications, with low latency and jitter tolerance among its strengths.

For more information on high-speed transmission systems and suppliers, visit the Lightwave Buyer's Guide.