Overview of wireless and mobile technologies.
Advances in signal processing technologies are a technological driver for wireless technologies. Different technologies like 3G (WAN), WLAN (LAN), Bluetooth (PAN) and WiMAX (MAN) target different applications and markets. Since most of the frequency spectrum is still regulated in the different countries, newer technologies aim for non-regulated bands such as the 2.4GHz and 5GHz ISM bands.
In order to fully exploit untethered operation, wireless devices are fitted with roaming and handover protocols like 802.11r or Mobile IP. Layer 2 protocols typically provide faster handover but are restricted to specific link layer protocols. Layer 3 or higher protocols like Mobile IP are independent of the link layer thus work across heterogeneous networks.