Could light bring us superfast mobile broadband indoors?
While 5G mobile broadband could give us superfast connectivity outdoors, the signal may not be able to reach indoors, particularly at higher frequencies.
So could broadband over lightwaves help supplement the mobile signal inside buildings? Telecoms firm O2 thinks it might.
Reporter: Chris Baraniuk. Video editor: Suzanne Vanhooymissen.
Click here for more stories, videos and features about 5G in our Connected World series