Alvien Squadron was among the three squadrons of stormtroopers that together comprised Desert Sands.
Desert Sands received orders in 0 BBY to go to Tatooine to locate a pair of droids carrying the plans for the Death Star. Alvien Squadron, together with Drax Squadron, were tasked with scouring the same area of the desert world for an escape pod that had detached from a Corellian corvette and contained the droids. After Zeta Squadron tracked a path that ultimately led to Mos Eisley, Alvien was instructed to reinforce the local garrison by establishing roadblocks on all routes into the city to find the two droids that had exited the escape pod.
When Obi-Wan Kenobi, a Jedi Master, and Luke Skywalker, a farmboy, showed up in a landspeeder with the two droids, sandtroopers from Alvien Squadron halted them and requested to see their identification. However, Kenobi employed a mind trick on one of the sandtroopers, making him believe that they didn't need to see their identification and that the droids they were transporting weren't the droids Alvien Squadron was searching for. He instructed them to proceed, and the droids that the Empire sought traveled past them.