A move by cellphone operators to use airwaves freely available in the same bandwidth as Wi-Fi networks has raised concerns that consumers' home Internet service could be disrupted, along with connected devices such as security monitoring systems. For the operators, who have spent billions of dollars on acquiring licensed frequencies, using the new LTE-unlicensed technology to tap into higher-frequency Wi-Fi spectrum could prove a relatively cheap way to cope with the explosive growth in data traffic, particularly within buildings.