Newly assigned to three mobile phones in December 2014 3.The operation of the 5GHz band will start this year.NTT DOCOMO is the first team.The company plans to use this band from June to provide 4G services with a maximum descent of 370Mbps.KDDI and SoftBank are also expected to start services in 2016.Use this time 3.The 5GHz band has a different characteristics from other mobile phones.2, not FDD (Frequency Division Duplex), which is widely used in mobile phones.AXGP and WiMAX2 operated in the 5GHz band.It is operated in LTE-Advanced (4G) using TDD (Time Division Duplex), the same as the BWA system such as 1 (WiMAX2+).The introduction of "TDD 4G" is the first in Japan.TDD is a technology that enables communication between "up" (transmitting terminal) and "down" (receiving side) using one radio wave (transportation waves) by time -division.Compared to the FDD that uses different transport waves on the up and down, more bandwidth resources can be assigned to the "down" side, which generates more data traffic, and efficient data communication can be performed.In the TDD version 4G introduced this time, the upper and lower ratio is 1: 3 to achieve a communication speed of up to 110Mbps down by one 20MHz width.Compared to the "FDD version 4G", which performs up to 150Mbps down and down 2 MHz width transportation waves, the downward transmission ability per bandwidth width is about 1 compared to the "FDD version 4G"..5 times.Arounded to DoCoMo 3.The bandwidth of the 5GHz band is 40MHz width.DOCOMO operates two waves of 20MHz width of TDD version 4G here (110Mbps x 2), which is operated in the upper and lower 20MHz width..The maximum communication speed of 370Mbps download is achieved by a three -wave carrier aggregation that combines the 7GHz band 4G (150Mbps).
