It’s no secret; we’ve all become data hogs. As today’s smartphone users consume ever-increasing network resources, mobile operators are rushing to deploy their LTE networks to meet subscriber demand. Given this trend, operators are already planning their LTE-A deployments. Delivering true 4G speeds, LTE-A will boost data rates from 150 Mbps to 1Gbps. LTE-A will also provide enhanced cell edge performance, much improved radio interference mitigation and spectrum re-usage. 

For subscribers, this translates to real-time HD voice and video services and fewer dropped calls. Operators implementing LTE-A can enjoy upsurges of network efficiency, monetized mobile broadband and increased network capacity. But what’s the best approach for an LTE-A deployment? 

Maximizing spectrum with carrier aggregation and interference mitigation

As with any new technology that brings vastly different features than its predecessors, the roll-out of LTE-A is best taken in steps, weighing on the tactical advantage of each feature. This phased approach will begin with the achievement of higher throughput through carrier aggregation and enhanced MIMO, and improved interference mitigation through the implementation of Enhanced Inter-cell Interference Coordination (eICIC) techniques. Using LTE-A, mobile operators can implement carrier aggregation both practically and efficiently, by leveraging the use of their existing spectrum to help achieve a higher bandwidth and heightened speeds. 

Carrier aggregation—a chief benefit of LTE-A—allows operators to consolidate their non-contiguous 3G spectrum and LTE frequency bands with LTE-A’s additional spectrum to enable more data throughput at one time. In effect, portions of existing spectrum can be combined to attain higher speeds, enabling up to 100 Mhz of usable spectrum. Increased spectrum capacity delivers the 1Gbps data rates required for high-demand services, such as HD voice and video. 

As most of the traffic load will still be seen indoors, small cells will play a crucial role in global LTE-A deployments and will underpin the key features of LTE-A technology such as carrier aggregation, key interference management features including Enhanced Inter-Cell Interference Coordination (eICIC) and range extension – all part of the LTE-A body of standards. 

In many Asian countries, the dense deployment of small cells makes it particularly prone to more interference and thus imperative to extend beyond traditional LTE with frequency reuse to provide the carrier aggregation and interference mitigation capabilities delivered by LTE-A. Because traditional LTE networks do not supply the necessary capacity and coverage to utilize eICIC techniques, LTE-A networks provide an improved solution for organizing small cells and macro cells. This ties back to carrier aggregation as it provides an effective means for mobile operators to use the available spectrum in chunks rather for increased capacity and coverage, rather than relying on the rare availability of a large section of contiguous spectrum. 

LTE deployments in Japan are already very mature, and mobile operators are ready to leverage LTE-A technology to solve these issues. In addition, small cells deployments in Asia often exist on a different frequency and there is more available spectrum, making LTE-A a natural fit. While Asia is leading the rate of LTE-A implementation, North American and European markets will soon follow, once their LTE architectures are sufficiently in place. 

Initial rollouts of LTE-A in Asia have provided opportunities for many lessons learned, including the realization that, when it comes to capacity management, redirection alone is not sufficient. Instead, sophisticated algorithms must be utilized to ensure adequate coverage during peak usage times, such as emergencies and rush hour. While imperative for the future of mobile, the robust functionalities of LTE-A add to the complexity of the roll-out process. The implementation of Self-Organizing Networks (SON) has served as a useful player in LTE-A deployment, in terms of solving the practical issues that come along with a mass rollout and architectural changes, as well as effectively aiding in interference mitigation.

Taking a tiered approach to LTE-A roll-out

Because the roll-out of LTE-A requires numerous architectural changes, operators are wise to deploy this technology in a tiered approach, beginning with carrier aggregation and interference mitigation. This is aided by eICIC techniques that enable better coordination in time domain between small cells and between small cells and macro cells, boosting cell edge performance. Small cells will continue to form a critical role in next-generation deployments. Using sophisticated techniques, eICIC mitigates interference on traffic and control channels. Because they have many of the same features as LTE-A networks themselves, small cells can be uniquely coordinated by LTE-A to provide enhanced cell edge performance. 

The second phase of an LTE-A roll-out will include Coordinated Multi-point (CoMP) techniques to ensure even greater performance is achieved at the edge. This complex technology is currently being tested in the lab, and will be deployed at a later date. Relay nodes are another feature to be considered for phase two or three in this tiered deployment approach, as they represent a substantial change in network architecture.  

With its powerful combination of capacity and coverage, LTE-A supports the growing relevance of small cells. Radisys recently announced the world’s first LTE-A small cell solution, which has been enhanced to include key LTE-A features that enable operators’ phased LTE-A deployments. As part of a Heterogeneous Network, or HetNet, the LTE-A small cell solution brings enhanced capacity and coverage.  

LTE-A addresses the growing needs of mobile by bringing increased capacity and coverage, delivering true 4G speeds by boosting data rates from 150 Mbps to 1 Gbps. In order to meet rising subscriber demands, boost network efficiency, monetize mobile broadband and increase capacity, a phased approach to deployment of LTE-A is most effective for operators. The tiered approach—beginning with carrier aggregation and interference mitigation—will offer operators the best opportunities to maximize efficiency, enhance cell edge performance and improve spectrum reuse for an optimal user experience. 

Renuka Bhalerao is a system architect with Radisys.