Certainly, the small area coverage networks like Bluetooth, LoPan, etc all have challenges with cost reducing and shrinking sizes of devices, muxes, antennae. The 802.11ac WiFi has substanatial beamforming and multipath demands, and potential needs for innovations in antenna designs - and of course the migration of these latest WiFi and Cellular LTE 5G systems toward providing shared services presents alot of challenges as far as performance, price & interoperability. I am sure that there are many more I am overlooking.