- The World's First Successful 2.5Gbps Transmission Experiment
is a milestone in realizing 3.9G and 4G -
HSDPA and 4G (Part 2)
Now that HSDPA has brought 3.5G into the realm of practical applications, the focus is now on the coming 4G and the steps needed to realize it. NTT DoCoMo is actively promoting R&D into 3.9G under the name of Super 3G, and is also conducting a variety of experiments aimed at practical implementation of 4G such as the world's first successful test on packet signal transmission at a maximum downlink speed of 2.5Gbps. Based on these topics, "Features" will reveal NTT DoCoMo's roadmap on 3.9G and 4G, and explain how the company is moving towards realizing these technologies.
Super 3G: Using 4G Technologies in the 3G Frequency Band
As the name directly implies, 3.9G is just a very short step away from 4G. At present, NTT DoCoMo is advancing the development of 3.9G aiming at a smooth transition to 4G.
"When we migrated from the 2G PDC network to the 3G W-CDMA network, we ran into some problems with regard to infrastructure construction. This experience led us to realize that in order to avoid the same problems a second time, we would need to implement communications services using 4G technologies on the existing 3G network. Obviously, this would be meaningless if it was only promoted by NTT DoCoMo, so to set a common standard we have been working with the members of 3GPP (Third Generation Partnership Project), a collaborative organization set up to standardize worldwide telecommunications technical specifications."
The major point of Super 3G technologies lies in their integration with the IP network.
"We are now planning to have an all-IP core network implemented at the time of 3.9G deployment. The IP network lowers both procurement and maintenance costs, as well as introducing services with higher speed and lower cost. However, it is also necessary to create a mechanism that guarantees security and reliability before migrating the system into the IP network. R&D for Super 3G at NTT DoCoMo takes this factor fully into account."
Further, from the viewpoint of extending mobile communications technology, studies are under way to integrate wireless communications services such as Wi-Fi and WiMAX. "Our proposal for Super 3G technology takes full consideration that this is a technology aimed squarely at 4G. In other words, we are focusing on providing mobile communications services at higher speeds by using certain 4G technologies on a mechanism of traditional cellular type services. This also means that collaboration with other wireless communications services is one of our themes, and we are closely examining how this should be done."
