T-Mobile turns to customers to improve its network T-Mobile (TMUS) is taking an unusual approach to improving capacity on its phone network, announcing on Monday that customers can get their own mini-wireless broadcast tower. Dubbed the 4G LTE CellSpot, T-Mobile's small plastic box plugs into a customer's home Internet connection and provides up to 16 nearby devices with full T-Mobile wireless signal, including the fastest LTE format. T-Mobile said the Cellspot would be free with a $25 deposit to customers on its Simple Choice plans. Wireless carriers have been experimenting with adding many more, smaller transmission points to relieve some of the congestion on their networks as iPhone-happy teens uploading ever more videos to Snapchat and their ilk threaten to overwhelm the capacity of the existing system. Some analysts think adding numerous smaller cells, called femtocells in the industry, could be a cheaper and more efficient way to expand capacity than building more...