Updating your AT&T cell phone to provide better reception can be done in a couple of ways. If you find that your phone is showing inadequate signal strength in an area where you normally obtain full signal strength, you may try one of these methods to increase your signal strength and update the reception so that you be able to make calls and data transfers with adequate speed and consistency.
Power cycle the phone to prompt it to connect to the AT&T GSM network and automatically download the latest carrier updates, which can improve reception. The carrier updates are a set of firmware settings embedded in the cell phone's circuitry. Over time, AT&T introduces changes to these carrier settings which can impact the performance of your AT&T cell phone's reception. Turn the phone off by pressing down the power key, then turn it back on to complete the power cycle.
Install an AT&T 3G MicroCell device in your home to improve reception. These devices are offered by AT&T to improve cellular signal strength in areas where you may unavoidably have poor reception. They use your internet connection to route phone calls and data transfers through your internet connection and increase the signal strength of AT&T devices that are being used in the immediate area of the MicroCell device.
Go to an area that you know usually provides adequate reception and phone call quality to update the reception. Although AT&T provides nationwide cellular coverage, you may live in a "dead zone" that isn't fully in a coverage area. In this case, you can simply limit use of the cell phone to areas which you know provide acceptable signal strength.