Deployment of C-RAN architectures has enabled increased deployment of optical mobile fronthaul solutions to deliver low-latency, high-bandwidth connectivity between remote radio heads and baseband unit electronics. Service providers are recognizing the necessity to reduce their mobile networking costs by better aligning the total electronics capacity of their networks with the total network utilization at any given time. They realize that by separating the electronics into a centralized pool where multiple radios or remote radio heads can share access to it, they can drive down capital costs and eliminate underutilized capacity. Centralized baseband units also enable easier handoffs and dynamic RF decisions based upon input from a combined set of radios. As service providers deploy C-RAN architectures, they face significant challenges and decisions, specifically the selection of their mobile fronthaul solution. The CPRI protocol is extremely latency sensitive, which results in a latency link budget that limits the distance between RRH and base-band units to less than 20 km. The mobile fronthaul transmission equipment must minimize its latency contribution, or this distance will become even shorter. CPRI signaling is also highly inefficient, consuming as much as 16x transmission bandwidth versus the actual data rate seen by mobile applications. To address which solutions best target these requirements, ACG Research analyzed the total cost of ownership and compared the economics of P2P dedicated dark fiber to that of active DWDM solutions like Fujitsu’s Smart xHaul.

We analyzed the operational expense of the Smart xHaul solution over five years and compared it to competing mobile fronthaul alternatives. The analyses focused on the deployment of 150 macro cell sites, each supporting three frequency bands and three sectors. We also considered deployment of five small cells per macro cell site for a total of 750 small cell deployments. The results demonstrate that although the capital expense of deploying a DWDM solution such as Smart xHaul is multiple times greater than the capex of P2P dark fiber, the reduction in fibers due to signal multiplexing and the advanced service assurance capabilities delivers 66% lower opex and 30% TCO savings. When looking at competing DWDM solutions, we also find that the advanced functions of the Smart xHaul solution deliver 60% lower opex associated with detecting, identifying root cause and resolving field issues. In addition, industry-leading features in the Smart xHaul solution provide the ability to distinguish between optical transport and radio service impairments, which are identified by inspecting the actual CPRI packet frames. When combined with the other performance monitoring and service assurance capabilities, CPRI frame inspection results in rapid issue identification, assignment and resolution.