There are a multitude of things which contribute to bad cell phone reception. First off, your distance and line of sight to your nearest cell phone provider’s cell tower determines how strong of a signal you have to work with. If you’re far away from the nearest tower, or you have objects in between you and the tower, such as trees, hills, large buildings, etc., then you’ll be working with a much weaker signal, which means that small interferences will cause major signal problems with your phone.
Assuming you have a decent cell phone signal, then you have to look at local causes of cell phone reception problems. Many times, the material that is used for construction on your home or office, such as different metals, wire mesh, insulation types, etc., can cause interference problems. Water is another material which is very detrimental to cell phone signal reception, so trees, plants, decorative waterfalls, pipes, etc., all can cause very bad cell phone reception problems.
The solution to many of the local problems is to use a mobile phone signal boosting kit, which uses an external antenna to tap into the strong cell phone signal, an amplifier to amplify that signal, and then an internal antenna to broadcast that signal to the area which is having reception problems. In essence, the kit bridges the interference and allows you to have signal in the area you need it.