It’s no longer a theoretical possibility. It’s already here. TeliaSonera has launched commercial LTE service in Stockholm and Oslo, claiming throughput speeds of up to 100 Mbps to subscribers. In Germany, Deutsche Telekom’s T-Mobile has made the first voice call over LTE using VoLGA, which might very well become the temporary enabler for voice-over-LTE before a permanent solution based on IP Multimedia Subsystem (IMS) technology will be ready to be implemented.
Besides TeliaSonera and T-Mobile, an impressive number of other leading Tier-1 operators have already expressed their commitment to LTE, including Orange, Verizon Wireless, NTT DoCOMo, and China Mobile. A survey published this past month by Infonetics Research, moreover, found that an impressive number of mobile operators around the world intend to roll out 4G services. It’s a given that those percentages are bound to only rise with time, especially once the voice-over-LTE quandary is finally settled.
For you, the mobile operator or service provider, however, the path to fullscale deployment and commercial success is still strewn with regulatory and technological hurdles, one of the thorniest being the “intelligence crunch” in the all-IP LTE backhaul network.
The challenge facing LTE rollouts is the backhaul network’s requirement for intelligent handling of the rich media traffic and new applications from the cell-site. Capacity issues in the access will be more easily resolved by extending fiber or high-bandwidth microwave to the eNodeB. LTE backhaul networks, however, are going to have to be significantly smarter and even more OpEx and CapEx sensitive than their 2G and 3G predecessors in order to ensure uniform service delivery over its disruptive flat and partial mesh architecture – as up to 32 eNodeBs can be interconnected via the X2 interface. This will require end-to-end Quality of Service (QoS) assurance as well as optimal linear or ring resiliency and accurate timing across the network. Of course, it will also necessitate backward compatibility for 2G and 3G service continuity, by handling TDM and ATM traffic as well as IP over the all-packet switched network.
The need for synchronization and timing over packet solutions is particularly critical. This is because clocking data, which is transmitted natively in TDM networks, requires special attention in packet switched networks, as these are asynchronous by nature and introduce packet delay variation and packet loss. As far as mobile operators are concerned, the backhaul network must meet or beat SDH/SONET performance levels to eliminate the risk of service disruptions, impaired cell hand-offs and excessive dropped calls. LTE, therefore, requires robust clock distribution to all network elements to ensure accurate handover. This includes frequency as well as phase and time synchronization.
But what does all this mean to the average subscriber who only cares about watching video, exchanging music clips, navigating country roads using GPS, or making online stock transactions? It means plenty – and even more to the mobile operator who has marketed the new LTE network based on user Quality of Experience. Because without an intelligent backhaul network, subscribers won’t be able to benefit much from the high capacity bandwidth LTE promises each user.
All of which inevitably brings us to the use of Carrier Ethernet as a transport mechanism for LTE backhaul.
Carrier Ethernet is a perfect fit for LTE backhaul because it offers simplicity, scalability and cost-effectiveness in resolving the intelligence crunch. Whether the backhaul network is self-built or operated by a transport provider, Carrier Ethernet based on the use of smart and cost-sensitive cell-site gateways and aggregation hubs can ensure a flexible selection of topologies and allow distributed intelligence from the cell site to the network edge to efficiently handle tens of thousands of backhaul connections with traffic management, end-to-end performance monitoring and hard CoS/QoS over LTE’s flat architecture while optimizing network resources.
In addition to enabling cost-effective backhaul sharing with customized SLAs and differentiated QoS, truly advanced LTE gateways, incorporating 1588-2008, Synchronous Ethernet, and other timing and clock distribution options, can also provide mobile operators and service providers with the flexibility to address different timing schemes used by the base stations, as well as help them avoid complete network upgrades with new hardware.
As operators and wholesale transport providers around the world are planning new LTE rollouts and the launch of interactive, multi-user and multimedia mobile services, they must prepare their backhaul networks to efficiently handle LTE’s abundant capacity while lowering TCO to make such deployments economically viable. RAD’s LTE backhaul solutions are specifically designed to meet these early deployment challenges head-on, providing affordable intelligence to optimize LTE bandwidth, deliver customized QoS and ensure SLA performance.
RAD Data Communications will be exhibiting its full range of LTE gateways and aggregation devices at Mobile World Congress, which will be held February 15-19 in Barcelona.
