Asian carrier show off LTE advances
SK Telecom demonstrates TM9 feature of LTE-A, while China Mobile is first with TD-LTE TV and carrier aggregation
Published: 31 January, 2013
Several LTE breakthrough demonstrations have been announced this week - usually a long way from mainstream products, but still a chance to showcase the features of emerging standards and influence the ones in which carriers and their suppliers choose to invest. These demoes are also a way for vendors and operators to position themselves as frontrunners, and the emphasis is increasingly shifting to Asia.
SK Telecom and Ericsson have performed the world's first demonstration of a core LTE-Advanced technology named Transmission Mode 9 (TM-9), which defines a method of transmission between mobile devices and base stations. Adopted by the 3GPP in 2011 as part of the standards, it is expected to be important in building HetNets of small cells. These networks will make it imperative to use various technologies to minimize inter-base station interference and enhance network stability.
TM-9 allows base stations to distinguish mobile devices and send different demodulation reference signals (DM-RS) to each one located within the coverage area. In addition, each base station uses its unique channel information reference signal (CSI-RS) to communicate with devices. This should create an optimal transmission environment for each individual device, ensuring a certain data rate, and increasing base station capacity and efficiency. The development and demonstration of TM-9 began in October 2012 and the resulting demonstration showed that TM-9 was able to increase data rates by 10% to 15% in areas of inter-cell interference.
"Together with CA (carrier aggregation) and eICIC (enhanced inter-cell interference coordination), TM-9 will provide a solid technological basis for maximizing service quality and performance in the LTE-A environment," said Kang Jong-ryeol, SVP and head of network technology at SK Telecom's R&D Center.
On the carrier aggregation side, ZTE claims to have completed the world's first download test using CA technology in a commercial environment. This was conducted in collaboration with the Guangdong arm of China Mobile in an outdoor TD-LTE network. It achieved a peak single-user download rate of 223Mbps at an uplink and downlink sub-frame ratio of 1:3. The special time slot ratio during the test was 10:2:2. In accordance with China Mobile specifications, a continuous networking environment was used for the test. The test also used CA (20MHz+20MHz) technology to verify key technical points like cell peak rate and mobility.
"This successful test has helped narrow the gap between TD-LTE and LTE FDD," said ZTE's general manager for TDD products, Bai Yanmin. "We are pleased with the results and will continue to work on spreading CA technology for commercial use."
Finally, for the first time in the world, TD-LTE technology has successfully been used for a live TV broadcast. On January 5, China Mobile's TD-LTE network transmitted a live video stream of the Xiamen International Marathon to the TV centers of China Central TV and Xiamen TV for live broadcasting. The network was built by Nokia Siemens which said that, despite the increased demand for network capacity with exceptional traffic and load conditions, there was no degradation in network performance, no packet loss and no delay during the 2.5-hour live transmission. The network uses NSN's SingleRAN platform with its Liquid Core EPC , Flexi Network Server and Flexi Network Gateway.