## 4 Implementation Details
### Generating Heterogeneous Arrivals
Due to the present limitation in the implementation, the bytes of \(T_{1}\) which are transmitted

Figure 3.1 Influence of Varying Fragment Size for Low Priority (CBR) Traffic. (**a**) Packet Size = 60B; (**b**) Packet Size = 120B; (**c**) Packet Size = 180B; (**d**) Packet Size = 240B; (**e**) Packet Size = 300B. prior to getting interrupted are considered lost. Therefore, with the increasing \(\mathrm{S_{FRAG}}\), the maximum delay is found to be increasing. This contradicts with the initial trends shown in Figure 14, where the delay is seen to be decreasing with increasing \(\mathrm{S_{FRAG}}\); as \(\mathrm{S_{FRAG}}\) increases and becomes equal to the packet size, the delay reduces as the packet is transmitted as a single unit without being interrupted. However, if the packet gets interrupted anywhere in between, it would face higher delay as compared to the case where \(\mathrm{S_{FRAG}}\) was low. Similarly, the influence of varying fragment size has been studied for the high priority traffic. The results for delay have been illustrated for each packet size (60B, 120B, 180B, 240B & 300B) in Figure 3.2 As compared to the results illustrated in Figure 14, those in Figure 15 depict opposite trend. This is because as the fragment size of \(T_{1}\) traffic would increase, \(T_{2}\) will face higher delays due to getting a lower chance to interrupt and having to wait for longer. Hence, it has been seen that for each packet size, the delay keeps on increasing for \(T_{1}\) and decreasing for \(T_{2}\), as the fragment size increases. Therefore, the fragment size should be chosen efficiently to improve the performance of MAC protocol for prioritized traffic scenarios. ## 7 Conclusions and Future Work

This paper has presented a high-level design and simulation results for a MAC scheme called FROG-MAC, which focuses on providing pre-emptive priority channel access to emergency data in WSNs. Existing protocols could not provide the emergency or high priority data with preemptive priority due to the design limitations. In contrast, FROG-MAC is proposed to offer the high priority

Figure 3.3 Influence of Varying Fragment Size for High Priority (Poisson) Traffic. (**a**) Packet Size = 60B; (**b**) Packet Size = 120B; (**c**) Packet Size = 180B; (**d**) Packet Size = 240B; (**e**) Packet Size = 300B. traffic with a chance of interrupting ongoing transmission of low priority traffic (using fragmentation). Therefore, FROG-MAC is expected to improve WSN performance for the applications requiring efficiency in terms of delay and reliability. MATLAB simulations show that by increasing the packet size, the delay and PDR both increase for both types of traffic, however the values were found to be significantly lower for the high priority traffic when fragmentation was applied. In addition, it has been observed that decreasing the fragment size of low priority traffic, high priority traffic becomes able to access the medium earlier, and hence its delay reduces. In future, we plan to fully develop a fragmentation-based MAC protocol FROG-MAC including all details such as CSMA, collision detection & avoidance, multi-hop transmissions etc. [PERSON] developed the idea, identified the research gap, worked on the protocol design and developed the implementation of FROG-MAC. This work is a part of [PERSON]'s doctoral dissertation. [PERSON] is the dissertation supervisor and moderated/offered guidance for all aspects of the paper. [PERSON] helped with the literature review and wrote the original draft. This research received no external funding. The authors declare no conflicts of interest. ## References

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