Verizon Communications Inc. has topped AT&T Inc.’s offer for Straight Path Communications Inc., according to a person familiar with the matter, sparking a bidding war over a tiny company that controls a swath of wireless airwaves thought to be at the forefront of next-generation networks.

Verizon US:VZ bid $1.8 billion for Straight Path, topping AT&T’s US:T stock bid of $1.6 billion earlier this month. AT&T, which has until next week to respond, said Tuesday it was evaluating the situation. Verizon declined to comment. Straight Path didn’t immediately respond to a request for comment.