Japan's NTT Docomo has long been at the forefront of mobile technology developments, leading the way as it did with mobile commerce and 3G, and it's no different in late 2013.
The Japanese operator, one of the mobile broadband industry's bellwether service providers, has developed, and has started to deploy (in a few major prefectures including Tokyo, Osaka and Kyoto), an indoor multiband small cell (mini basestation and antenna) that is compatible with the 1.5GHz and 1.7GHz frequency bands as well as the 2GHz band. (See Asia-Pac's 4G Advances.)
Docomo, which had 15 million 4G customers at the end of July 2013, offers its Xi 4G LTE service over the 2GHz, 1.7GHz, 1.5GHz, and 800MHz bands.
According to NTT DoCoMo Inc. (NYSE: DCM), these small cells can currently deliver downstream speeds of up to 150 Mbit/s (theoretical) over 4G LTE connections, and are already compatible with LTE-Advanced. When Docomo launches its commercial LTE-A service, which is due in the next few years, the maximum downstream speed will increase to 225 Mbit/s, the service provider says. For more details, see this press release.
Providing indoor coverage of mobile broadband services is regarded as critical for 4G service providers, but it's hard to achieve. (See Huawei Broadband World Forum 2013 Highlight Video and Sprint Has Samsung 4G LTE Small Cells: Analyst.)
Docomo also recently announced it had achieved a world first by transmitting wireless data at a speed of more than 1.2 Gbit/s by using a single antenna incorporating a new technology being developed for LTE-Advanced deployments called Smart Vertical MIMO.
According to Docomo, the technology enables a single antenna to "achieve throughput equivalent to that of a four-antenna system," allowing mobile operators to reduce the cost and space of installing antenna equipment while also improving "spectrum utilization efficiency. Space reduction is particularly beneficial for deployments in congested urban areas," notes Docomo in this announcement.
— Ray Le Maistre, Editor-in-Chief, Light Reading