4G wireless technology is taking the industry by storm and proving to be the answer to future-proof new and existing wireless networks. Two technologies have spawned from this next generation and Long Term Evolution, or LTE for short, is quickly becoming the network technology of choice for 4G deployments around the world. As user demand for mobile broadband services continues to rise, LTE and its ability to cost-effectively provide fast, multimedia mobile data services appears to be the right technology at the right time.

According to the Global mobile Suppliers Association (GSA), as of August 2010 there are 101 firm LTE network deployments planned or in progress in 41 countries around the world. By the end of 2010, GSA anticipates around 22 LTE networks in commercial service. In addition to these statistics, another 31 operators are currently engaged in various LTE pilot trials and technology tests, which when added to the above translates to 132 operators in 56 countries that are now investing in LTE.

For many operators, LTE represents a significant shift from legacy mobile systems as the first all-Internet Protocol (IP) network technology that will impact the way networks are designed, deployed and managed. More specifically, mobile operators will need to deal with specific challenges that LTE raises, such as interoperability with legacy and other 4G systems, ensuring end-to-end network quality of service (QoS) and hiqh-quality service delivery and interaction with IMS for the delivery of multimedia services and voice.

With the long-term evolutionary access technology that is LTE, the 3GPP (Third Generation Partnership Project) systems are well positioned to remain competitive for at least the next 10 years. LTE embodies a vision of wireless access that assumes a whole-sale transition towards a packet switched only system that is distinctly non-hierarchical, and which makes wide use of Internet Engineering Task Force (IETF) protocols and practices. LTE is further designed to be interoperable with legacy UMTS systems and offer support for seamless mobility through non-3GPP wireless accesses including, but not limited to, WiMAX, 1x-EVDO and Wi-Fi.

The LTE access network incorporates state-of-the-art air interface technologies including OFDMA (Orthogonal Frequency Division Multiple Access) and advanced antenna techniques to maximize the efficient use of RF spectrum. It also accommodates several options for frequency bands, carrier bandwidths and duplexing techniques in order to effectively utilize the different portions of unused spectrum available in different countries and geographies. Additionally, and significantly, the LTE network architecture evolves to all-IP architecture, enabling the seamless delivery of applications and services over what were previously two separate and distinct networks, while QoS options which allow for real time packet data services like VoIP and live video streaming.

As a wireless network which improves spectral efficiency, simplifies deployment of all-IP real-time services, facilitates integration with non-wireless networks and supports interworking with legacy wireless technologies, LTE is strongly positioned to lead the evolution in the communications industry for several years. It achieves all of these things through a flat, scalable architecture which is designed to manage and maintain service QoS in a mobile environment.

Implementing IMS with LTE enables acceleration network convergence with the promise of flexible service delivery. Mobile operators will count on LTE to implement cost-effective network changes as preparation for IMS. Deploying SIP-based control architectures on broadband wireless IP-based LTE is a natural fit for IMS.

For operators overlaying existing wireless networks, LTE supports interworking with the legacy 3GPP and non-3GPP wireless accesses. The intention is to provide LTE service continuity that is transparent to the access technology. Access independence is one of the requirements of the NGN visions. The idea assumes a generic approach, which decouples the NGN core network and its procedures as much as possible from the access technologies.

The pursuit for ever-higher data rates, higher capacity, higher user throughput, lower latency, more efficient use of the radio spectrum and more flexibility fueled the need for a departure from the inherent limitations of UMTS (and its many evolutions) by, among other things, its CDMA-based air interface. LTE ensures a viable future for mobile broadband by enabling:

1. Data rates an order of magnitude higher than single-carrier spread spectrum radio can provide
2. Reduced transit times for user packets (reduced latency), an order of magnitude shorter than can be provided in hierarchical 3G networks
3. The ability for strict QoS control of user data flows with the possibility of these being coupled with various charging schemes

Despite all of its benefits, LTE is not without its challenges. Operators wishing to take advantage of what LTE offers must consider migration strategies from legacy 2G/3G networks, reconsider how services are developed and deploy IP networks which can deliver low-latency end-to-end in order to support real-time QoS. This may include interim device strategies, leasing access on third-party IP networks, implementing IMS architectures and supporting real-time services like VoIP and streaming video over IP.

Operators wanting to implement a real-time service like VoIP will have to carefully monitor network latency. This said, deploying LTE should offer overall cost savings and future revenue opportunities. LTE meets the market needs of improved performance, reduced cost and better value.

Keith Cobler is senior marketing manager at Tektronix Communications.