Summary
What most operators have been doing in the early phases of deploying EV-DO or HSDPA is to provision additional T1/E1s, either over their own microwave infrastructure or by spending more on leasing T1/E1 services from a wireline service provider. The last two to threeyears have seen most 3G operators spend on provisioning an additional one or two T1/E1s at their 3G cell sites, just to support the very first wave of early adopters of mobile broadband.
Analysis
The cutting over of HSDPA and EV-DO functionality at the base station has typically been preceded by the deployment of one or two additional T1/E1s at the operator's 3G cell sites to provide the additional capacity required. The challenge for operators now is to prepare the backhaul for an acceleration in the takeup of mobile broadband. There isn't much doubt that it will happen: It's a matter of exactly "when," not "if." In Japan, 75% of NTT DoCoMo's subscribers are already 3G W-CDMA subscribers, while only 25% still have 2G terminals. Over time, and at different rates, consumers will adopt the latest technology. There is also a lot of evidence from operators showing that adoption of HSDPA and EV-DO tends to generate a marked spike in data traffic over the old GPRS, R99 W-CDMA, and CDMA 1X-RTT networks.
Across the backhaul network, just adding more of the same TDM or ATM capacity isn't a viable medium- or long-term solution to prepare the network for the data-oriented traffic and revenue model that is now emerging. As operators prepare to drive adoption of mobile broadband services from 3-4% of their subscriber base up to 10-20%, investing more in these legacy technologies will only serve to depress profitability.
The solution is to transition from TDM and ATM to Ethernet as the new Layer 2 transport protocol of choice across the backhaul network. A 10-Mbit/s carrier Ethernet service priced at less than four or five T1/E1s is increasingly common, as is a Gigabit Ethernet service priced much lower than an STM1/OC3. The path to Ethernet-based backhaul is now explicitly recognized by mobile network planners throughout the world as the strategic direction they need to take. The issue is primarily one of the specific timing and the specific model of introducing Ethernet backhaul.
