Nortel demos LTE handoff

Nortel Networks has moved its Long Term Evolution (LTE) trials out of the lab and into the field, claiming to have achieved the industry’s first handoff between live cell sites during a recent test at its development center in Ottawa.

Using prototype Nortel LTE radio and network gear and prototype handsets from 4G development partner LG Electronics, Nortel said it has demonstrated LTE handover at speeds of 100 km per hour between cell sectors, maintaining an HD video stream in the process. Data speeds for the tests, however, averaged 10 Mb/s over a 10 MHz channel in Canada’s Advanced Wireless Services (AWS) band. That’s far from the theoretical 100 Mb/s or so promised by the LTE standard, but Nortel officials said that, just as in 3G and 2G before it, real-world conditions will vary far from theoretical limits.

“We’ve demonstrated far greater speeds in the past but in a non-handoff environment,” said Danny Locklear, Nortel vice president of marketing for carrier networks. In June, Nortel demonstrated data speeds of 50 Mb/s in a car traveling 110 km per hour but remaining in the same cell sector. The demands on the network for true mobility—i.e. with multiple handoffs—is much greater, Locklear said. “In this kind of environment, the network will have to be very robust from cell to cell, sector to sector.”

Nortel is on pace with the rest of the industry to produce trial LTE gear early next year and its first commercial base station line by the end of 2009. LG is on a similar timeline to produce LTE devices and handsets. Nortel is one of three North American vendors selected by Verizon Wireless and Vodafone to supply trial networks for their future 4G launches, and just as Nortel has been active in fine-tuning its LTE platform, Alcatel-Lucent and Motorola have been doing the same. Alcatel-Lucent has formed a joint venture with NEC to develop an LTE kit, which gives the French-American vendor immediate exposure to what will likely be the first commercial LTE deployment, NTT DoCoMo’s in Japan.

Meanwhile Motorola has focused on a unique business case for LTE in the US: the integration of CDMA networks with LTE, which is being developed by the GSM standards body, the Third-Generation Partnership Project. Not only has Verizon Wireless committed to LTE, but CDMA operators Alltel and MetroPCS have also tapped the technology. Motorola has already performed live tests of CDMA-to-LTE handoff.