Barry gets lousy cell phone reception at work. Leo says there are signal repeaters such as the Wilson Electronics Cell Phone Signal Boost. Barry would place the antenna in a place where there is signal, and it would send the signal to the booster which would repeat it.
If Barry doesn't have signal anywhere near his office, a device called a Femtocell or MicroCell would work. This will route his cellphone calls through his Internet connection. It's like a mini cellphone tower that connects via the Internet. They're not very expensive, either. So that may be the best solution, and if he goes to his carrier and says he wants to cancel the service without one, they may just give him one.
Republic Wireless is a very inexpensive carrier that allows phone calling over Wi-Fi. They do it very well, and the handoff from Wi-Fi to cellular works seamlessly.