Multicore Packet Processing Forum

Archive for June, 2011

By Charlie Ashton, VP of Marketing – 6WIND

At last week’s Linley Tech Carrier Conference in San Jose, several processor suppliers discussed their strategies for supporting the “Cloud RAN” architecture in LTE networks. Talking to people at the conference, it was interesting to hear widely diverging opinions on prospects for this concept.

By way of background, the Cloud RAN (Radio Access Network) concept is a recent approach to reducing both the CAPEX and OPEX of the LTE RAN. In the conventional network architecture, each antenna connects to a co-located eNodeB from which traffic is backhauled to the Evolved Packet Core (EPC) over an IP link. With the Cloud RAN approach, however, the eNodeB at the antenna is replaced by a low-cost Remote Radio Head (RRH). The digitized RF data is then connected via CPRI over a fiber link to a centralized processing cluster in which the baseband processing is performed. This fiber link to the centralized cluster can be up to 40km in length, so in theory the baseband processing could be centralized and aggregated for cell sites over an area with a radius of up to 40km. That’s a lot of cell sites and users.

Proponents of the Cloud RAN architecture point to the advantages of distributed Remote Radio Heads in terms of reduced cost, reduced power consumption, smaller footprint (mounted directly on poles) and lower maintenance cost (simpler units with less electronics). They also stress the efficiencies of the centralized baseband processing cluster such: as better utilization of processing bandwidth (no need for individual processing subsystems at each cell site to be sized for the peak load only encountered at a single period during the day); flexibility of location (can be placed anywhere that’s convenient); lower overall power consumption. They point to existing deployments in Korea and China as evidence that the concept has been proven in at least some locations.

Contrasting with these CAPEX and OPEX advantages, though, detractors talk about the reliability issues associated with a centralized processing cluster that represents a single point of failure for cell sites covering a wide geographical area, while also pointing out the costs and logistical challenges associated with running fiber to a wide number of cell sites often placed in inconvenient locations.

I suspect that in the long run, as with any new technology that clearly has technical merits, the Cloud RAN architecture will be adopted in some geographical areas but not others and will become viewed as an alternative LTE implementation architecture that is appropriate in some situations.

What do you think? Is the future for this disruptive technology “cloudy” or “fair”?