Vivint Smart Home Inc, a home automation company backed by Blackstone Group, on Monday agreed to merge with a company funded by a unit of Japan's SoftBank Corp to create a firm with an enterprise value of $5.6 billion. Vivint makes a range of home security products and hubs that help in controlling other automation gadgets, such as Amazon Echo and Google Home, through a central touchscreen panel. Blackstone, which bought Vivint in 2012 for more than $2 billion, will retain its investment in the company and invest an additional $100 million.