Technology mix improves cell-edge experience

Oct 09, 2015

• DT removes intra-site cell boundaries using smart technology mix
• Peak performance of 150 Mbps reached at cell-edge area
• Innovative concept is based on a DT and Samsung joint IPR

Deutsche Telekom (DT) takes the first step towards user-centric networks. In Lingen, DT has demonstrated consistent user experience on its test LTE network. During the trial on its live network grid, DT successfully deployed Inter-Sector MIMO (IS-MIMO) to bring peak performance to the cell-edge area and improve the overall LTE-A customer experience by up to 50 percent. Inter-Sector MIMO is a new and innovative technology concept jointly developed by DT and Samsung to solve the challenge of limited throughput at the cell edge.

"Deutsche Telekom continues to drive the development of LTE," says Bruno Jacobfeuerborn, Chief Technology Officer, Deutsche Telekom. "Our customers demand a seamless user experience wherever they are on our mobile networks."

"Building upon Samsung 's Smart LTE, IS-MIMO will be a disruptive technology to deliver uniform service quality regardless of user location." said Dong Soo Park, Executive Vice President and Head of R&D Team in Networks Business at Samsung Electronics. "Since the network will be more and more complex to support billions of devices and extended throughput for immersive contents, IS-MIMO will be a key technology required for future networks."

How IS-MIMO works

In conventional LTE networks, the maximum reachable LTE user experience (150Mbps) is only achievable close to the antenna where the signal is strongest. As the customer moves further away from the antenna the signal gradually weakens, until the customer eventually experiences an extremely limited throughput in the area between two intra-site sectors. This is caused by inter-cell interference in LTE.

With IS-MIMO, all intra-site cells combine to create one cell and the data signal is transmitted to the user terminal from the best source. No terminal assistance is required, irrespective of whether the signal is transmitted from a single or two separated intra-site eNodeB antennas. As well as bringing peak performance to the cell edge area, the trial demonstrated that the IS-MIMO concept improves the overall LTE customer experience by up to 50 percent. In the Lingen field trial, Deutsche Telekom was able to demonstrate that the IS-MIMO combination extends the area where LTE-A customers can reach the maximum throughput of 150 Mbps. Furthermore, the trial was able to measure a maximum throughput at the cell edge area. This shows the capability of IS-MIMO to effectively remove the cell edge area between two intra-site sectors via cell combining and MIMO streams transmission from adjacent sectors.

IS-MIMO and Carrier Aggregation make a good team

DT and Samsung also successfully demonstrated a combination of carrier aggregation and IS-MIMO. With IS-MIMO on one or more carriers, more consistent customer experience over a given coverage can be achieved. This concept was jointly developed in the framework of a DTAG/Samsung Innovation Cooperation project which was launched in 2013.

The demonstration of the feasibility of this technology is an important step on the way to realistic IS-MIMO commercialization. "This results of this trial are an important milestone in LTE Advanced", adds Jacobfeuerborn. "As innovation leaders in LTE Advanced, we will continue to work with our partners in the industry to develop this technology into a commercial solution on a device for our customers."

Good to know

Carrier Aggregation (CA) is an important technology in the LTE standard for bundling two and more carriers to provide higher peak rates rather than additional capacity. Multiple Input Multiple Output (MIMO) is another technology in the LTE standard to improve network performance in terms of coverage, spectral efficiency and throughput.