Consult with your telecommunications provider (mobile operator). It is possible that your home or office are located in the so-called "dead zone" of the cellular connection. If so, you can apply directly to the office of the operator and apply to improve the quality of communication. It would be nice if your application will be collective. Then the probability of a quick review of your appeal and the positive reaction to it will increase. Usually in such cases the operators make installation of additional antennas in this area.
If the operator is nothing can help, sign a contract with him about the installation of individual external antenna to enhance cellular signal (repeater). To conclude such an agreement should be because your antenna might later interfere with the operation of base stations.
Select a location for the antenna. Try to route signal as much as possible of the buildings, trees and other obstacles. Consider thus and on which floor is your apartment or office.
Go online and select the company responsible for the installation of such structures. Create an order for installation services of repeater. Do not attempt to install the repeater on their own, if you do not have the sufficient qualifications. By the way, you may well save money if you buy an external antenna and sign a service contract with the same company. Be sure to check the presence of the company's certificate safety equipment.
Do not fall for advertising all kinds of improvised devices for signal amplification (for example, the pads under the battery). First, the acquisition of such devices will greatly facilitate your wallet, and secondly, they are absolutely useless.