For the low cost, and short range communication IEEE has defined layers called physical (PHY) and medium access control (MAC).
Physical layer
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 …show more content…
If there is any abnormalities found, alert should be given to the patients. So, the communication of WBANs with other network plays a crucial role.
Power usage is the important factor in choice of wireless technology. The existing and emerging radio technologies suitable for WBANs are: UWB, ZigBee and IEEE 802.15.4, Bluetooth and a few leading competitors in WBAN markets such as Z-Wave, Zarlink, RFID, Rubee, ANT and Sensium. Based on the requirement of WBAN application we can select different radio technologies. Comparison of various radio technologies are shown in figure. Ultra Wide Band is used for short distance transmission with a high data transfer rates. It consumes only low power. For implant application Zarlink technology is used. Since it has low data rates.
The radio technology which has efficient transmission distance, low power consumption, high security, long battery life is Rubee. Most commonly used radio technology is ZigBee.
One significant disadvantage of Zigbee is the interference with WLAN transmission,