Sprint selects DragonWave’s workhorse for WiMAX backhaul

As Sprint has reported before, it is having trouble finding suitably fat pipes to backhaul its new high-capacity broadband WiMAX network. T-1s pumping out 1.5 Mb/s just aren’t cutting it, but what Sprint has chosen as an alternative almost seems like overkill: DragonWave’s Horizon platform, which when deployed at full capacity supports 1000 times the bandwidth of a T-1.

Sprint revealed today that DragonWave will be its third microwave backhaul equipment vendor along with Alcatel-Lucent and Ericsson. Specifically Sprint will buy its Horizon Compact and newly unveiled Horizon Duo microwave radios. DragonWave bills the Duo as the highest capacity wireless link in the industry, its dual-pole cross-polarization scheme supporting between 1.4 Gb/s to 1.5 Gb/s of capacity over a full 50 MHz channel. DragonWave, however, said Sprint selected the Horizon platform not just because of its capacity muscle, but also for its ring-and-mesh network architecture as opposed to the typical hub-and-spoke architecture. The mesh lay-out maximizes the efficiency of fiber points of presence by distributing traffic across multiple fiber nodes.

Sprint said it would deploy the radios in Chicago, Baltimore and Washington, the three networks targeted for commercial launch this year. It’s highly doubtful Sprint will need the full 1.5 Gb/s of capacity for each base station, which DragonWave concedes is useful primary to backhaul aggregation points from multiple base stations. Sprint may opt to deploy scaled-down versions of the radio, supporting 10 Mb/s connections or higher. But as the capacity demands increase, Sprint can upgrade the radios through software to support greater capacities.

Sprint chief technology officer and 4G President Barry West has said that the WiMAX network will require 30 Mb/s to 40 Mb/s of backhaul capacity to meet the high-bandwidth demands of its users. That kind of bandwidth can’t be met through copper, so West said Sprint has been looking for direct fiber connections where possible, supplemented by microwave links. Some of those links are being provided by backhaul middleman FiberTower, but Sprint has been deploying its own microwave gear also. The difficulty in finding or supplying those links, however, led to delays, forcing Sprint to push back its second quarter launch until later this year. The first network is expected to go live in Baltimore in September.