It's back to the future for XO.XO Holdings "launched" a company that bore it six years ago. The CLEC reintroduced Nextlink as a provider of fixed broadband wireless services to businesses, government agencies and other service providers.In 2000, CLECs Nextlink and Concentric merged to form XO.Nextlink utilizes licensed Local Multipoint Distribution Service (LMDS) wireless spectrum covering 75 metropolitan markets across the country. The service will be marketed as an alternative to conventional broadband services delivered over copper and where fiber is unavailable or cost-inefficient.With this asset, Nextlink will be targeting "middle mile" applications such as wireless backhaul and wireless metro Ethernet. Nextlink estimates that backhaul is currently a $2 billion market that will more than triple by 2010.Wireless metro Ethernet, which is less than a $1 billion market now by Nextlink estimates, is expected to double through 2009.Nextlink's services, offered in the 28GHz - 31GHz range, are for locations up to seven miles and in line-of-sight of a Nextlink wireless hub. Speeds range from 1.544Mbps T-1 up to 622Mbps OC-12 in point-to-point or point-to-multipoint configurations.Though XO has had the LMDS spectrum for several years, fixed broadband wireless has never taken off. Emerging operators Winstar, Teligent and Metricom went bankrupt early this decade, while at the same time AT&T Wireless closed its operations, Sprint scaled back its fixed wireless plans, and MCI sold off its fixed wireless assets to Nextel.Nextlink is initially launching service in Dallas, Los Angeles, Miami, San Diego, Tampa and Washington, DC, with additional market launches over the next two years.