It used to be simple. Almost all cellular basestations were connected by separate backhaul connections that didn’t use any precious cellular spectrum, whether fibre, copper, point-to-multipoint wireless, point-to-point wireless or satellite. There were a few scenarios which used repeaters. More recently we’ve seen LTE relay and other technologies come into play for outdoor small cells. Here we look at several different levels of inband and out of band small cell backhaul.