RAD Gateways Enable T-Mobile to Use DSL to Transport HSDPA Backhaul

January 15, 2008: T-Mobile is ramping up its backhaul infrastructure in readiness for the latest generation of mobile HSDPA data services. To do so, it is deploying gateways from RAD Data Communications. The pilot phase in Germany has concluded with successful tests, and expansion based on RAD's ACE-3000 gateways is now in full swing. These gateways give T-Mobile, the mobile communication subsidiary of Deutsche Telekom AG, the added option of connecting HSDPA-enabled NodeBs (3G base stations) via low-cost ADSL2+ lines and drawing on the services of its sister company T-Com. Equipment from RAD is also to be used in other T-Mobile networks later on.

"HSDPA needs more bandwidth. So T-Mobile wanted an economical solution to expand what are known as the 'mobile backhaul' links between base stations and radio network controllers (RNCs)," says Adolf Nadrowski, VP RAN Strategy at T-Mobile Germany. "It made sense to do without expensive E1 leased lines and, instead, access a very well-developed DSLAM infrastructure and T-Com's transport networks and buy DSL backhaul as a service."

For UMTS and HSDPA backhaul, however, the 3rd Generation Partnership Project (3GPP) has singled out ATM as the standard technology for the time being. Ethernet-enabled mobile equipment is only gradually being introduced as a platform for packet-switched transport infrastructures. That explains why NodeB manufacturers still only supply their equipment with E1 interfaces, and not the Ethernet interfaces that they would need to connect to DSL lines. The same goes for RNCs, which still feature STM-1 interfaces and, therefore, remain ATM devices.

"We rank as a pioneer in the field of pseudowire technology. This order from T-Mobile thus comes as powerful confirmation that we are on the right track," notes Volker Bendzuweit, Managing Director of RAD Data Communications GmbH. "In the phase where conventional telecommunication technologies are giving way to dedicated packet-switched infrastructures, there is vast potential for strategies that use virtual lines to emulate services."

To enable ATM services (E1 UNI or STM-1 UNI) to be emulated over packet-switched services (Ethernet/MPLS/IP), gateways in the ACE-3000 series employs ATM PWE3 (pseudowire emulation edge-to-edge). The RAD gateways use pseudowire technology between NodeBs (i.e. HSDPA base stations) and RNCs (Radio Network Controllers) to emulate ATM tunnels through Ethernet networks. By doing so, they enable backhaul resources to be allocated at low cost – and facilitate delivery of the latest 3G services.