The digital processing uses a fast Fourier transformation (FFT). This allows the allocated band to be scanned at the highest possible speed over a wide range of frequencies. The FFT algorithm is used in many protocols such as IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.16, ZigBee, Bluetooth, and GSM/WCDMA. An FFT analysis takes the time on the digital processor but can have effects on additional costs for the device.
Mobile phones so far have worked with analog radio signals. The cellular telephone bands are in the analog spectrum and at first consist of the three different GSM bands (850 MHz, 900 MHz, 1800 MHz) and their associated DCS bands (1710 MHz, 1750 MHz, 1900 MHz). With the development of digital signal processing, digital technology allows the frequencies to exist in the digital spectrum on the same way as the internet frequencies use fiber optic cables instead of copper cables. For that purpose, a specific radio can use the digital modulation on top of the analog signal, which will then be demodulated by a DSP to obtain the original digital message.
With the popularity of smartphones, different mobile carriers across the globe now offer a separate plan for Internet access. For instance, China Mobile offers a 3G PC Internet plan. The plan allows users to access the Internet on personal computers while the smartphones are allowed to make a mobile calls and 3G network data. 7211a4ac4a