The 802.16 Physical Layer

MCANetworkInternet

The IEEE 802.16 is a set of standards that lays down the specifications for wireless broadband technology. It has been commercialized as Worldwide Interoperability for Microwave Access (WiMAX) that is responsible for delivery of last mile wireless broadband access. It lays down the standards for both physical layer as well as medium access control (MAC) layer for WiMAX.

Physical Layer Features of WiMAX

  • There are two popular services of the physical layer −
    • Fixed WiMAX.
    • Mobile WiMAX.
  • WiMAX initially provided data rates of 30 – 40 Mbps. The updated version that came in 2011 provides up to 1 Gbps data rates for fixed stations.
  • It operates in the frequency band of 2 GHz to 11 GHz. The bandwidth is dynamically allocated as per user requirements.
  • WiMAX uses orthogonal frequency division multiplexing (OFDM) with 256-channels. Mobile WiMAX uses scalable OFDM.
  • It uses convolutional codes, particularly Reed – Solomon Codes for forward error correction (FEC) to deal with damaged frames.

Fixed WiMAX

Fixed WiMAX was released in 2003. They are for subscriber stations that are stationary in some fixed location. For example, broadband Internet for homes and offices. Fixed WiMAX uses OFDM.

Mobile WiMAX

Mobile WiMAX was released in 2005. They are for mobile stations that receive service while they are in motion within the range of WiMAX. For example, a WiMAX equipped vehicle. Mobile WiMAX uses scalable OFDM.

raja
Published on 04-Feb-2020 14:50:24
Advertisements