1. Bin Liu, Zhisheng Yan, and Chang Wen Chen
CA-MAC: A Hybrid Context-aware MAC Protocol for Wireless Body Area Networks
Bin Liu, Zhisheng Yan, and Chang Wen Chen
Dohwan Kim

2. Table of contents
WBAN
CA-MAC
Simulation
Conclusion

3. WBAN
Wireless body area network (WBAN) is a body- centric system which consists of body-worn sensors and master node.
Sensor nodes collect and transmit various kinds of data including heart rate, ECG, blood glucose and EEG.
TDMA-based MAC and contention-based MAC are known as two basic channel access mechanisms for wireless sensor network (WSN).

4. CA-MAC CA-MAC is a new hybrid contention/TDMA MAC.
The length of beacon and the whole frame is fixed but the proportion that contention part or TDMA part occupies is changed adaptively.

5. CA-MAC 𝐶𝐿 𝐼 𝑖 : contention length index
𝑁𝐶𝐷 𝑃 𝑖 : the number of consecutively dropped packets from one sensor node.
𝑇𝐷𝐶 : the times of data collision among all sensor nodes.

6. CA-MAC

7. CA-MAC

8. Simulation

9. Conclusion
CA-MAC can overcome challenges resulting from time-varying traffic and channel conditions in WBAN.