USB 3.0 is slowly rolling out, and in 2010 you're likely to begin to see it showing up in the next generation of laptops, portable hard drives and other devices. NEC, however, reckons that it's just managed to triple the speeds that a serial bus connection can achieve.
USB 3.0 can theoretically manage 4.8Gb/s speeds, but NEC thinks it can reach 16Gb/s, using the same stream of 1s and 0s that SuperSpeed USB uses. The development, which is just a chip right now rather than a bus, could pave the way for USB 4.0 hitting even higher rates.
The current speed limit is in place because signals get mangled over long cables. Normally this problem is worked around by sending a signal back down the pipe to say that the data has been received correctly - but the faster the data transfer, the faster this check has to be.
NEC has added a delay in this feedback process, which reduces inter-bit interference and gets around the issue somewhat - upping the ceiling for data speeds considerably. The next step is for the people who look after the USB standard to license the technique, then we might see it integrated into the next version. We'll keep you posted.