As WiFi moves to the heart of large carriers’ network strategies, companies like Ruckus and Ericsson’s BelAir are coming into their own. Such firms have been using clever antenna technology to turn a technology devised for LANs into a platform suited to telco-class broadband. But they will not be able to rest on their laurels, as a clutch of new start-ups are waiting to challenge them. One is Mimosa Networks, which has closed a third round of funding, worth $20m, to support its gigabit WiFi system, which is particularly targeted at rural access. The funding round was led by previous investor New Enterprise Associates, with participation from Oak Investment Partners., taking the start-up’s total financing to date to over $38m.…