IP/MPLS Backhaul to the Cell Site

Year-to-year growth of mobile data traffic held a fairly straight line until 2006. But by mid-year, the volume of mobile data traffic began to skyrocket. Since then, mobile data growth has continued to grow exponentially and that growth shows no signs of slowing down any time soon.
The sudden increase in mobile data traffic volume coincided with widespread consumer acceptance of new high-speed mobile services such as music and video downloads, multimedia e-mails, mobile IM, ringtones, etc. Today we have 2.5G and 3G next-generation radio technologies that mobile operators have deployed to support these services. Making their debut are High Speed Packet Access (HSPA), WIMAX and in the future, Long Term Evolution (LTE).
2006 has seen mobile data usage pass the critical point as traffic has turned from linear growth to exponential growth. Looking forward, Juniper Networks believes this trend will continue powered by HSPA, LTE, UMB and WiMAXto support highspeed applications.
A key piece of the mobile network left untouched, however, has been the mobile backhaul network. Mobile backhaul, also known as Radio Access Network (RAN) backhaul, plays a vital role in today’s mobile networks because it acts as the link between the cell site/base station transceiver system (BTS) and the base station controllers (BSCs) in the RAN, and the networks to which mobile data traffic is being transported.
Those networks include the Internet, other mobile networks, traditional landline networks or private networks. Lacking a more cost effective alternative, most mobile operators simply continued to use expensive leased T1/E1 or T3/E3 lines for mobile backhaul of their data traffic.
Deployment of 2.5G and 3G technology meant base stations that previously required one or two T1/E1’s for backhaul now needed four to six T1/E1’s. The result has been a 200% to 400% increase in required backhaul capacity and its associated increase in OpEx costs. Additional mobile backhaul methods in use today include SONET/SDH, ATM, microwave and emerging techniques such as Ethernet, DSL and WiMAX.
Mobile operators’ backhaulrelated OpEx costs continue to balloon because they are using all of these technologies separately to backhaul legacy voice traffic as well as highvolume data flowing to and from their networks. As a result, mobile operators are spending more than 30% of their OpEx budgets on just mobile backhaul. Not surprisingly, carriers’ mobile backhaul networks are becoming strategic assets and an area of major investment. Therefore, carriers have a strong desire to future proof those assets.
At a time when their importance is increasing exponentially, the current state of mobile backhaul networks is not conducive to mobile operators’ efforts to achieve their most important goals:
- Rolling out new high speed data services to improve ARPU and customer stickiness.
- Simultaneously decreasing OpEx and CapEx while leveraging existing backhaul assets.
Carriers are looking for ways to reduce OpEx in order to compensate for declining ARPU, increasing competition and new technologies. And, while they need to roll out new IP-based services in order to survive and thrive, carriers still must provide and protect legacy non-IP-based services. This is because they will continue to comprise a significant share of their revenue streams for many years to come.
To achieve their goals, mobile operators realize that they must upgrade their legacy backhaul networks because presently they do not have the flexibility or scalability to cost-effectively support co-existing services on the same network. Nor do they offer ease of provisioning/ planning/network management that is so vital to reducing OpEx. And carriers also understand that in the not-so-distant future they will want to connect their networks with other service providers in order to generate revenue and differentiate themselves from their competitors. To do this they will require a means of separating and securing traffic and maintaining SLAs. Next-generation mobile backhaul solutions must address all of these concerns.

NEXT GENERATION MOBILE BACKHAUL REQUIREMENTS
As mentioned above, mobile operators’ existing backhaul networks accommodate a wide variety of base station technologies on separate networks for each technology – TDM (for 2G), ATM (for UMTS), etc. In addition to being difficult to scale and too complex to manage, legacy backhaul networks provide mobile operators with very limited visibility into the performance of individual circuits. This is unacceptable because carriers have so much to lose if they are unable to meet their service level agreements (SLAs).