The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( Trefis) -- After postponing for months, Sprint ( S) may finally call off its deal with LightSquared. Sprint extended its Dec. 31 deadline to March 15 in order to give LightSquared more time to secure regulatory approvals for its LTE network plans. However, the FCC said last month that it will not be able to grant clearance for the proposed network as the potential interference issues with GPS receivers could harm public safety. With Sprint's relationship with Clearwire ( CLWR) on a much stronger footing now, it makes little sense for Sprint to continue to hope for a LightSquared turnaround. Sprint is scrambling to get its LTE network up and running in a few cities by the middle of this year as rivals Verizon ( VZ) and AT&T ( T) continue to add more markets to their expanding LTE footprint.