TD-LTE, which will be used by Softbank, was originally designed only for data and will therefore be able to dynamically allocate bandwidth as needed between uplink and downlink channels. This means that if downloads are congested, needed bandwidth can be taken from the uplink channel. This provides an advantage for data over FDD-LTE that is used by the other carriers and was originally designed for both data and voice.
WiMAX, available from UQ WiMAX (under KDDI), presents four main differences from LTE (from a consumer's point of view).
- LTE data plans replace 3G plans, but Wimax is an option added to an existing 3G plan currently for and additional ¥525.
- WiMAX currently has no usage limits.
- WiMAX has a 2 year head start on Docomo Xi and has a corresponly much larger coverage area of 100 million people.
- WiMAX uses a higher frequency than competing LTE networks and is therefore more easily attenuated indoors/underground.
KDDI (AU) is currently offering WiMAX. They will roll out LTE from 12/2012, starting with 60% coverage of the population at 75 Mbps. By the beginning of fiscal 2015, they plan to have 96.5% coverage.
Softbank 4G is currently available with an advertised maximum downlink of 110 Mbps (this is apparently not being attained, but 60 Mbps is still good). By the start of fiscal 2013, they expect to cover 99% of the population. Only routers are currently available.
SBM has also announced a FDD-LTE network by mid 2012, but it is unclear if this schedule will be met because of the unfair allocation of channels by the government. AU and Docomo enjoy two channel bands, while SBM is limited to one. This means that SBM has to totally bring down it's LTE network to build out new technology.
The MIC is auctioning off a new allocation of 900 MHz spectrum to only one carrier. If SBM gets it, they're golden. If not, their kinda screwed. [UPDATE: Interestingly, SBM rolled it out for 3G.]
E Access (Emobile) is starting LTE service from the start of fiscal 2012. After one year, they expect to cover 70% of the population. Urban downlink will be at 37.5 Mbps. In rural areas downlink will be 75 Mbps. If they win the 900 MHz allocation, it would likely have an effect on their LTE plans.