The mobile operator is undertaking an end-to-end infrastructure upgrade in preparation for its 5G roll-out. : The mobile operator is undertaking an end-to-end infrastructure upgrade in preparation for its 5G roll-out. Mobile network operator Three UK has announced its commitment to pump more than £2bn into an infrastructure upgrade that will prepare it to deliver 'market leading' 5G services to customers in 2019. Those services will include wireless home broadband, via Three's UK Broadband-operated subsidiary Relish.