Bringing LTE service to up to 128 users within 1km
Smartphone users often experience a significantly reduced data rate in crowded urban areas, as a large number of users have to compete for the limited data capacity of the nearby base station they are connected to. To address this challenge, researchers at ETRI have developed SW technologies for small-cell base stations which can be widely deployed in such urban areas to bring much more satisfactory LTE service to the users.
The LTE-based small-cell SW technologies are targeted for base stations that aim to cover smaller areas compared to the existing cellular networks. Small-cell base stations can be viewed as wireless Access Points (APs) that serve users within a radius of around one kilometer, and expected to cover blind spots, where signal reception is poor, such as edge areas where the existing cellular networks cannot reach and dense areas packed with buildings. As a result, the same capacity (or even higher) and better coverage with fewer blind spots can be accomplished.
Once this technology is commercialized, small cell base stations can be installed as a set-top box on street lamps in areas packed with buildings, making them to cover areas with a radius of from 100 meters to one kilometer. This will lead to more pleasant LTE service for up to 128 users in each small cell.
Small-cell base stations for higher capacity
In addition to the development of SW technology for small-cell base stations in 2015, the researchers went further to develop an advanced technology called Carrier Aggregation (CA); it combines multiple frequency bands to obtain a larger bandwidth to achieve higher capacity. Applying this technology to five non-contiguous frequency bands, each of which 20MHz wide, for the first time, they demonstrated that the CA technology is capable of supporting each mobile terminal with a maximum data rate of 750Mbps, the best performance in the world known so far.
Among many others, a comprehensive framework for software development and testing, quality assurance algorithms that take users’ radio resources into account, uplink power control, interference coordination, and radio resource management are the key elements of the technology.
To differentiate their products from foreign products in the market, the latest technology features a zero-copy technique that enables high-speed data transmission, MAC scheduling algorithms that ensure Quality of Service (QoS) for users and achieve optimized resource allocation in various CA scenarios, and radio resource management tailored for distinctive characteristics of small cells. A unified development platform running in Windows PCs includes all these features, and it is this platform that makes it possible to streamline the software development process; it emulates multiple virtual mobile terminals as well as fluctuating wireless channels around them to test new products before installing them onto testbeds to conduct real-world testing.
ETRI’s unique technology to help small and medium-sized enterprises
According to a market survey, macro base stations account for approximately 98% of the current telecommunication industry, but small-cell markets are expected to have a greater presence in five years.
As the SW for small-cell base stations currently available in the country is entirely from imports, various challenges remain: weakened cost competitiveness, lack of technological differentiation, and delayed product release. However, ETRI’s independently developed technology is anticipated to address most of these problems.
The technology is expected to save about USD 58.58 million in royalties paid to foreign companies for the coming five years from 2017 by Korean companies in the market of small-cell stations. Upon global market entry, it is also expected earn a turnover of USD 2 billion for five years.
The technology has recently been transferred to a manufacturer of mobile communication equipment. The researchers are planning additional technology transfers to defense industries, private network providers, testing equipment suppliers, moving base stations, and in-vehicle technology developers.
