1. Max do Val Machado Raquel A. F. Mini Antonio A. F. Loureiro DCC/UFMG DCC/PUC Minas DCC/UFMG IEEE ICC 2009 proceedings Advisor ： Han-Chieh Chao Student ： Hsing-Hung Cho Date ： 2011/08/09 1

2. Outline ABSTRACT INTRODUCTION SENDER VS. RECEIVER-BASED DATA COMMUNICATION RECEIVER-BASED MEDIUM ACCESS CONTROL MODEL CHECKING SIMULATION RESULTS CONCLUSIONS 2

3. ABSTRACT Both MAC and network layers of the protocol stack are responsible for data communication in these networks This work proposes the Receiver-based Medium Access Control (Rb-MAC) protocol to be used in a combined solution with a receiver-based routing scheme Simulation results reveal that receiver-based data communication has a great data performance Authors use a model checking technique to perform the formal verification of Rb-MAC 3

4. INTRODUCTION Developing data communication protocols in a combined way is of prime importance in WSNs The goal of the MAC layer is to optimize the use of the wireless communication channel and to avoid collisions in the medium 4

5. INTRODUCTION MAC layer has another special task that is controlling the sleeping and waking up periods of a node, like Duty-cycle In networks with dynamic topology, such as the WSNs in which sensor nodes periodically go to sleep to save energy This work proposes a combined solution between MAC and network layers for WSNs considering the receiver-based perspective 5

6. INTRODUCTION In sender-based routing protocols using an updated neighbor table for choosing the next hop in the route if a node uses an outdated neighbor table, it can select unavailable sensor nodes to continue the routing process In receiver-based routing protocols need no table when a node receives a packet, it decides itself whether to forward the packet or not 6

7. INTRODUCTION Most of the MAC protocols for WSNs are based on principles that maintains an updated neighbor table and, consequently An energy-aware combined data communication solution should consider both MAC and routing protocols that do not require updated neighbor tables 7

8. SENDER VS. RECEIVER-BASED DATA COMMUNICATION Trajectory Based Forwarding (TBF) is a sender-based algorithm since the current node uses the curve equation to choose the next hop on the route Trajectory and Energy-based Dissemination (TEDD) is a receiver-based scheme since when a node receives a packet, it uses the curve equation to decide itself whether it should relay the packet or not 8

9. SENDER VS. RECEIVER-BASED DATA COMMUNICATION Sensor MAC (S-MAC) & Battery Aware MAC creating and update neighbor tables to deal with the dynamic topology of WSNs Geographic Random Forwarding (GeRaF) & Implicit Geographic Forwarding (IGF) there are some MAC protocols for WSNs that do not use these tables 9

10. RECEIVER-BASED MEDIUM ACCESS CONTROL 10

11. RECEIVER-BASED MEDIUM ACCESS CONTROL 11

12. MODEL CHECKING Using the symbolic model checker NuSMV to scan the states of a graph that represents our model ϕ 1: Each state s is reachable from the s0 and s0 is reachable from each state s. 12

13. MODEL CHECKING ϕ 2: If a node looses packets at the MAC layer, Rb-MAC is at the sleeping or collision states. ϕ 3: Rb-MAC is at the sleeping state if and only if its sleeping mechanism is at the sleeping state. 13

14. MODEL CHECKING ϕ 4: If Rb-MAC is at the sleeping state, the MAC and network layers do not receive nor send packets. 14

15. MODEL CHECKING ϕ 5, ϕ 6, ϕ 7 and ϕ 8 are fundamental to guarantee that both layers perform the receiving and the sending tasks without any interference 15

16. MODEL CHECKING ϕ 9: The MAC layer cannot receive and send packets simultaneously. ϕ 10: The network layer can receive and send packets simultaneously. 16

17. MODEL CHECKING ϕ 11 and ϕ 12 are important to guarantee the order in which the packet should be processed along the protocol stack 17

18. MODEL CHECKING ϕ 13 and ϕ 14 are crucial to the transmission phase of Rb-MAC since they guarantee the correctness of collision avoidance and treatment mechanisms 18

19. SIMULATION RESULTS The number of nodes is varied between 250 and 1250 The radio range of nodes is equal to 100 m They are randomly deployed in a 1000×1000 m2 sensor field Periodically performs a serie of unicasting disseminations to 10 sensor nodes chosen randomly at each round This node sends 20 messages for each destination Network Simulator is using (NS-2) 19

20. SIMULATION RESULTS We compare it with S-MAC For both Rb-MAC and S-MAC, we consider the values of 0.7 and 0.3 for the duty cycle 20

21. SIMULATION RESULTS 21

22. SIMULATION RESULTS 22

23. SIMULATION RESULTS 23

24. SIMULATION RESULTS 24

25. SIMULATION RESULTS 25

26. CONCLUSIONS Authors proposed Rb-MAC to be used in a combined data communication model with receiver-based routing protocols They compared this solution with a sender-based data communication that uses an updated neighbor table The proposed solution presents a great data delivery ratio, and reduces energy consumption, latency, number of transmissions, and collisions 26