802.16

In the past few years, broadband wireless access system has already caused the wide attention of people, it has the advantages of less investment, quick construction, higher transmission rates for a series of advantages.BWA system adopts multipoint network structure, support for voice, data and video services.A typical LMDS system, it is a kind of fixed broadband wireless access systems, IEEE 802 Committee was established in 1999 802.16 working group dedicated to the development of broadband wireless access standard.IEEE 802.16 is responsible for the broadband wireless access wireless interface and related function in the setting of standards, it consists of three small work groups, each small working groups which are responsible for different aspects of

IEEE802.16.1 is responsible for the frequency of 10 ~ 60GHz wireless interface standard ; IEEE 802.16.2 is responsible for the development of broadband wireless access systems coexistence with respect to the standard ; IEEE 802.16.3 responsible for frequencies in the range of 2 ~ 10GHz access frequency licensed for use in the application of the wireless interface standard.I E E E802.16 standard is concerned with user's transceiver base station transceiver between wireless interface package PHY MAC specification.

IEEE 802.16 protocol structure

IEEE 802.16 protocol standard is in accordance with the two layers of structure system, which defines a physical layer and a MAC layer.Figure 1 gives 802.16 protocol stack structure.

The most basic is the physical layer, the standard defines the physical layer is 10 ~ 66GHz, the spectrum is the default for local multipoint distribution service ( LMDS) spectrum, the protocol is mainly on the frequency bandwidth, modulation mode, error correction technology as well as the transmitter and receiver between synchronization, data transmission rate and time division multiplexing structure wait for a respect.At the same time, the working group has modified the basic IEEE 802.16 standards to adapt to low frequency.Modify the IEEE 802.16a for 2 ~ 11GHz public band, currently has formally announced ; revision of the 802.16b is to meet 5 ~ 6GHz ( sometimes called it U-NII band) without authorization application needs.

The physical layer is the medium access control layer MAC, on the layer in accordance with IEEE 802.16 is to provide service for users of the various functions.It is mainly responsible for the data frame format consisting of transmission and on how users access to the shared wireless medium in control.