Layers Of Wban And Medium Access Control Essay
For the low cost, and short range communication IEEE has defined layers called physical (PHY) and medium access control (MAC).
Clear channel assessment (CCA) within the current channel, activation and deactivation of radio transceiver, data transmission and reception are the tasks that is done by the physical layer. There are different physical layers. The choice of physical layer depends on the applications. The different physical layers are: Narrow Band (NB), Human Body Communication (HBC) and Ultra Wide Band (UWB).
NB physical layer is used for the activation or deactivation of the radio transceiver and data transmission and reception. The PSDU (Physical Layer Service Data Unit) needs to be pre-appended with Physical Layer Preamble (PLCP), to construct PPDU (Physical Layer Protocol Data Unit). PLCP is used for packet detection and for timing synchronization. PSDU contains the MAC header, MAC frame body and Frame Check Sequence (FCS). The modulation technique used by NB PHY layer are: Differential 8-Phase Shift Keying (D8PSK), Differential Binary Phase Shift Keying (DBPSK) and Differential Quadrature Phase Shift Keying (DQPSK).
HBC Physical layer provides Electrostatic Field Communication (EFC). This EFC covers modulation, Start Frame Delimiter (SFD) and packet structure. In this layer PPDU consists of PLCP preamble, PSDU and PLCP header. The PLCP preamble and SFD are created using 64-bit gold code sequence. When the receiver receives the…