DoCoMo's LTE is quick, but quickly disappoints

IDG News Service - NTT DoCoMo's LTE (Long-Term Evolution) data network, launched in three of Japan's biggest cities on Dec. 24, promises speeds of up to ten times those of current 3G wireless. Over the last few days I've had a chance to test network performance in central Tokyo, and I found that while it does occasionally offer significantly faster downloads than 3G, the current LTE network generally under-performs and suffers from slow upload speeds.

DoCoMo began building the network in December 2009 and testing started in June 2010. Between April 2010 and March 2011, the company will invest ¥35 billion in the initial LTE roll-out and will follow that with an additional ¥270 billion investment by March 2013 to put LTE in major cities across Japan.

The service launched with two data modems, a USB device from LG Electronics similar to the one used by Verizon in the U.S., and an Express Card from Fujitsu. NTT DoCoMo provided the LG modem for the test.

I visited several locations in central Tokyo listed as having LTE coverage and attempted to connect via LTE. At all the locations I recorded the speed of downstream and upstream traffic by hitting Speedtest.net servers in Tokyo, Okinawa and Seoul. I also recorded comparable 3G speeds from the same locations with an LG 3G modem.

In most locations the LTE signal, when available, was strong. It typically measured three bars out of three on the PC software, but I didn't have to walk far from each area to see the signal drop or disappear completely. That's perhaps understandable for a new network and isn't disastrous because the modem falls back to an HSPA 3G connection when LTE isn't available.

A bigger area of concern was the connection speed.

NTT DoCoMo advertises the LTE service as offering outdoor download speeds of up to 37.5Mbps and upload speeds up to 12.5Mbps. Getting those speeds isn't expected in practice, but I was hoping for downloads at between 10Mbps and 25Mbps.

In most locations I didn't get even that.

Outside one central Tokyo railway station the fastest speed recorded to speedtest.net's Tokyo server was 5.9Mbps, and outside a second station it was 7.7Mbps. Outside NTT DoCoMo's headquarters in the Nagatacho district the connection peaked at 5.7Mbps.

For comparison I made connections over DoCoMo's 3G network in the same three locations and got speeds of 1.7Mbps, 3.8Mbps and 2.3Mbps respectively.

DoCoMo's 3G network is advertised as offering speeds of up to 7.2Mbps, so these three represent between 23 percent and 51 percent of the theoretical maximum. The LTE network was delivering between 15 percent and 21 percent of the top-speed.