The tests took place under controlled conditions inside the company's 4G research and development centre at the Yokosuka Research Park outside Tokyo. They were designed to evaluate some of the technologies that are expected to be part of future 4G packet-switched wireless data systems.
Such technology is not expected to be commercially deployed until at least 2010 and much work remains before real-world trials can begin. However, with much of the 3G development work completed and its deployment begun, the thoughts of some in the telecommunications industry are now turning to 4G.
Fourth-generation systems are expected to be capable of transmitting and receiving data at speeds far beyond the 384Kbps or 2.4Mbps that 3G systems can handle, as NTT DoCoMo's tests indicated.
That extra capacity will require much more bandwidth, around 100MHz or 20 times that of 3G W-CDMA (Wideband Code Division Multiple Access) channels, posing a particular challenge to engineers. Such wide channels are much more susceptible to interference and signal reflections from buildings or other objects outside, so the first trials were undertaken indoors away from such factors, NTT DoCoMo said.
NTT DoCoMo established its 4G research lab earlier this year and is participating in a Japanese government drive to develop key 4G technologies by 2005.