Personal Area Network (PAN--
provides communication over a short distance that is intended for use with devices that are owned and operated by a single user);
Wireless LAN (WLAN--
a local area network that uses radio signals to transmit and receive data over distances of a few hundred feet);
Wireless MAN
(WMAN--a metropolitan area network that uses radio signals to transmit and receive data); and
Wireless WAN (WWAN--
a wide area network that uses radio signals to transmit and receive data

Wireless networks as obvious from name are the networks having no means of physical medium such as cords, wires or cables. This gives the advantage of mobility and extension of the applications to different parts of building, block and even anywhere in word. Wireless network can be divided into four basic categories in order to differentiate between there quality and range:

Category Coverage

Wireless Personal Area Network (WPAN) | Within One person
Wireless Local Area Networks (WLAN) | Within a building
Wireless Metropolitan Area Networks (WMAN) | Within a city
Wireless Wide Area Networks (WWAN) | Worldwide

i hope it will help you!