DoCoMo 4G Tests Hit 300Mbps
By Carlo Longino, Tue Jun 01 15:45:00 GMT 2004
Your brand-spankin'-new 3G phone is nearing obsolesence: NTT DoCoMo reveals the results from a new 4G test system.
DoCoMo says it's hit a peak of 300Mbps, with an average rate of just 135Mbps in a car moving at 30kph at a distance of 800m to 1km from base stations. The engineers aren't satisfied, of course, and plan to throw multiple-input multiple-output (MIMO) into the mix to crank standstill rates up to 1Gbps -- yes, that was a G -- to fit the ITU's 4G definition: 1Gbps standstill and 100Mbps when moving at train-like speeds.
The company's in acronym heaven, as the system uses variable spreading factor orthogonal frequency code division multiplexing (VSF-OFCDM) downstream technology, and direct spread code division multiple access system (DS-CDMA) for the upstream. Evidently you need all those letters for such high speeds.
The only potential downside that's obvious so far is that a line of sight to a base station is required for the higher speeds, something that is undoubtedly a problem in urban areas. But 135Mbps should be feasible for most people's needs for the forseeable future. There's no word from the company for a development timetable, so it's gonna be just a while yet, so go pick that 3G handset back out of the trash can.
It does beg one question -- what the hell do you do with all that bandwidth? DoCoMo did say as part of the test it sent two HDTV video signals at 25Mbps each that resulted in "stable" video quality, so expect a wristwatch that can process that video on the fly to show up in Akihabara in the next few months.