Sprint Xohm service to launch in September

Backhaul delays and a pending joint venture with Clearwire are not clouding Sprint's plans for mobile WiMAX service in Baltimore.

The city of Baltimore, Maryland will be the first to offer commercial mobile WiMAX service on the Sprint Xohm network. The announcement of September service was made by business unit president Barry West during last week's WiMAX Global Congress in Amsterdam. Washington DC and Chicago are expected to join Baltimore during the last three months of the year as the first cities with Xohm service. The Charm City ranks 20th on the US list of largest metropolitan areas.

Initial products at launch in Baltimore were confirmed to include embedded WiMAX laptops using Intel chipsets, the Nokia N810 Internet Tablet WiMAX Edition, a Samsung PC Card, a ZTE USB dongle and a ZyXEL CPE modem. Other vendors and products are expected to be approved by Sprint for use on the network and enter commercial availability in the future.

According to West, 575 base stations are online, though he didn't say which markets are counted in that statistic. Lack of sufficient capacity for the backhaul portion of the Xohm network (the connection between the WiMAX base stations and the core of Sprint's network) had been cited as the primary reason for delaying launch in April. West told the Amsterdam audience that this issue has been resolved through incremental connections using fiber-optics and microwave radio links. The majority of cellular backhaul in the US occurs over leased T-1 copper lines capable of 1.544 Mbps data capacity. Voice requires little capacity in contrast to the demands for broadband data services, where each mobile broadband user could access 1.0 Mbps and more of data. Sprint's JV partner, Clearwire, estimates that 60 Mbps of backhaul capacity is needed at launch for each of their mobile WiMAX sites.

Leased DS-3 lines -- offering 45 Mbps in each direction -- would be the next step up beyond a T-1 circuit and carry a heftier price tag with them. The other challenge in using copper circuits for the build of a large network is time. In many instances, there are not enough of them trenched or strung across poles to reach the places operators need. Microwave point-to-point connections have been used for decades as a stop-gap while copper and fiber is deployed. The microwave links have performed so well that operators often choose to leave them deployed instead of financing more wire build-outs.

Sprint's Xohm Insider added that, "WiMAX network preparations continue in Dallas, Fort Worth, Boston, Providence, and Philadelphia. Launch dates for those cities have not yet been decided."

By Jeff Orr

ORR Technology, LLC

Tuesday, June 24, 2008 in Deployments  | Permalink |  Comments (3)