A cross-layer based TDMA protocol for wireless biomedical sensor networks

In WBSN, it is important to ensure that packets can be sent to the medical centre reliably and efficiently. There have been numerous solutions adopting CSMA/CA to access networks. However, CSMA/CA can't give delay guarantee or QoS guarantee. TDMA can solve the problem, but TDMA takes no account of transmitting order so that it limits the improvement of network performance. This paper presented Q-TDMA, a cross-layer based TDMA protocol which allocates slots by virtual wireless links. Based on DSR routing information, Q-TDMA builds virtual wireless links, and allocates links to data flow. Q-TDMA also counts packets buffered in LLC queue to adjust priority and then adjust schedule dynamically. The simulation result shows that Q-TDMA performs better than TDMA. It's especially applicable to guarantee QoS for urgent data transmission in WBSN.