Interest in the new technology "LAA (Licensed-Assisted Access Using LTE)", which allows the 5GHz band used in wireless LANs to be used in a mobile phone system, has increased in Japan.NTT DOCOMO announced in August 2014 that it had a successful LTE communication in Beijing and LAA in Beijing.It is also attracting attention as a means to secure the operation frequency of 5G (5th generation mobile communication system), which is planned to commercialize in 2020.When will LAA be put into practical use and how will it have an impact on the mobile communication market?Cover the world with LAA and LTE-U 5GHz band and 2.Frequency bands such as 4GHz band are called "unlike bands" because devices such as wireless LANs can be used without obtaining a wireless station license.In Japan, LAA is an interference avoidance technology that is required to be installed on devices that use the ltepe-advanced (hereinafter referred to as LTE-ADVANCED), which are already the mainstay of mobile phone systems.It will be compatible with "LBT (Listen Before Talk)" so that it can be operated in an assembly band.It is a part of the next technical specification "RELEASE13", which is solidified in the spring of 2016, with the standardization organization of the mobile phone system "3GPP".
| 図表 LAAのイメージ |
In 3GPP, (1) Rather than using the unlicensed band alone, it is always operated in a carrier aggregation (CA) with a mobile phone frequency band such as 2 GHz band, and communication control etc. The basic concept is solidified, such as operating the LAA at a small cell base station so that it does not give interference as much as the wireless LAN. In fact, the technical standards for using the unlicensed band in LTE include another LTE-U (LTE-UNLICENSED), led by the US Quarcom, with Alcaterel Lucent, Elixon, Quarcom, LG. The LTE-U Forum, a promotion organization that Samsung and Belizon participate, are engaged in standard formulation and commercialization. So what is the relationship between LAA and LTE-U? "In Europe and Japan, the technical standards for shared bandwidth in Europe and Japan are stipulated by law in Europe and Japan, but in North America, etc. in North America. It is possible to introduce it if it can be controlled with existing systems. Therefore, we are trying to create a standard that assumes introduction in North America, etc. in the LTE-U Forum so that it can be introduced without waiting for standardization in 3GPP. " And explain the position of LTE-U.
| クアルコムジャパン 標準化担当部長 城田雅一氏 |
The technical standard of Japan's 5GHz belt equipment is considered to be the harshest in the world, and it is required to have advanced control, such as stopping radio waves once for 4 milliseconds, performing a career sense, and resuming communication.In LAA, it seems that significant changes in LTE specifications are required to support these specifications.On the other hand, LTE-U, on the other hand, aims for early commercialization with a wireless LAN and other factors with another technology (CSMA/CSAT) that can be implemented relatively easily in LTE.
