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Cox Demos 400 Mbps Upstream

Cox Communications is claiming to have set the world record for the fastest upstream cable transmission, showing off a 400 Megabit per second link using Motorola Mobility's DOCSIS 3.0 equipment.

Cox and Motorola demonstrated the 400 Mbps connection over 12 channels, in a 5-85 MHz return path, at the CableLabs Winter Conference in Atlanta this week. The demo used Motorola's RX48 return path receiver module in a BSR 64000 DOCSIS 3.0 cable modem termination system edge router.

That came after Cox's Las Vegas network had achieved 356 Mbps upstream in the 5-85 MHz return path across 12 channels, of which six channels employed 256-QAM modulation (as opposed to 64-QAM maximum in use today). Typically, hybrid fiber coaxial (HFC) networks today have no more than three upstream channels delivering an aggregate of 40 to 70 Mbps.

"The RX48 and these tests demonstrate that Cox's HFC networks are much more future-proof than many have believed," Cox senior vice president of technology Jay Rolls said in a statement. "Our networks have the capability to support much higher data speeds than today without the need to replace any of the amplifiers, taps or cables."

Also in Vegas, Cox and Motorola laid claim to a record maximum transmission rate of 141 Mbps over a 5-42 MHz return path, using six upstream channels (with three of those channels able to operate using 256-QAM modulation).

Cox's Las Vegas HFC network feeds a three-amplifier cascade followed by an HFC optical link consisting of a standard Motorola DFB return path laser transmitting over 7 dB of fiber to the optical receiver. The output of that receiver was linked to the RX48 card in the BSR 64000.