An Energy Consumption Analytic Model for Wireless Sensor MAC Protocol

1. An Energy Consumption Analytic Model for Wireless Sensor MAC Protocol Eric MAKITA http://link.koreatech.ac.kr Septembre 2012

2. Abstract

3. Some sensor products adopt IEEE 802.11-like MAC Protocol. However, IEEE 802.11 MAC is not a good solution for WSN. • S(Sensor)-MAC proposes enhanced schemes such as periodic sleep and overhearing avoidance to provide a better choice for sensor applications.

4. This paper presents an analytic model for evaluating the energy consumption at nodes in a S-MAC based WSN.

5. I. INTRODUCTION

6. Sensor network lifetime will rely on the corresponding batteries of sensor nodes. • IEEE 802.11 is one of the dominating MAC Protocol in current times. However, the power control function of IEEE 802.11 can not satisfy the requirements of sensor network application. • In this paper, we propose an analytic model estimating energy consumption of sensor nodes adopting S-MAC.

7. II. RELATED WORK • [1]-Measuring and reducing energy consumption of network interfaces in hand-held devices • [2]- An energy-efficient MAC protocol for wirelesssensornetworks • [3]- PAMAS: Power awaremulti-accessprotocol with signalling for ad hoc networks Optimizingsensor networks in the energy-latency-density design space • Optimizing • [4]- sensor networks in the energy-latency-density design space, • [5]- University of california, berkeley, mica2 schematics

8. II. RELATED WORK • [6]- An adaptive energy efficient MAC protocol for wireless sensor networks • [7]- An adaptive energy-efficient and low-latency MAC for data gatheringin sensornetworks • [8]- Performance analysis of the IEEE 802.11 distributed coordination function • [9]- Redefining internet in the context of pervasive computing

9. II. RELATED WORK • [10]- Performance analysis and enhancement for the current and future IEEE 802.11 MAC protocols • [11]- Performance of reliabletransport protocol over IEEE 802.11 wireless LAN: Analysis and enhancement • [12]- Queueinganalysis and delay mitigation in IEEE 802.11 random access MAC basedwirelessnetworks • [13]- Data gathering in sensor networks using the energy*delay metric

10. III. S-MAC • In the conventional IEEE 802.11 protocol ,there are several disadvantages causing unnecessary energy waste. • Every nodes hears transmission of all neighboring nodes even if the packet is not destined to itself. • Besides, considerable control packet may increase overhead in energy consumption. • The last one is idle listening, a node keeping listening to possible traffic for itself all the time.

11. IV. S-MAC ANALYTIC MODEL • Energy consumption of a node running S-MAC : E(t) = NT (t)ET + NR(t)ER + TS(t)PS + TI (t)PI (1) • Energyconsumption for transmitting a packet: ET = PTx(tRTS + tdata) + PRx(tCS + tBO + tSL+tCTS+ tACK + 3tSIFS + DIFS) (2)

12. IV. S-MAC ANALYTIC MODEL • Energy consumption for receiving a packet: ER = PTx(tCTS + tACK) + PRx(tRTS + tdata+3tSIFS + tDIFS) (3) • Number time the nodesendspackets: • NT (t) = λTt (4) • Numbertime the nodereceivespackets: • NR(t) = λRt(5)

13. IV. S-MAC ANALYTIC MODEL • S-MAC sensor node goes into sleep mode in three cases: • scheduledsleeptime • Receiving a RTS frame from its neighboring nodes • Receiving a CTS frame from its neighboring.

14. IV. S-MAC ANALYTIC MODEL • Sleep time • Fig (6) • Idle Listening time • Fig (7) • In S-MAC, the sleep schedule for a node will be synchronized with all its neighbors • psucc=nτ (1 − τ )n−1/1 − (1 − τ )n (8) • Extra idle period occurs when a node finishes a packet transmitting or receiving. • e= NI ×Tframe/2 • By deriving the unknowns in (1) using (2) (3) (4) (5) (6) (7) (8) (9) , we can evaluate the energy consumption of a node in analytic method

15. IV. S-MAC ANALYTIC MODEL • The chain-hop topology used in validating our analytic model: Sink Source 0 1 2 3 4 Fig. 1

16. IV. S-MAC ANALYTIC MODEL • Another topology used in validating our analytic model Sink_1 Source_0 3 0 2 Fig. 2 1 4 Source_1 Sink_0

17. V- ANALYTIC RESULT A. Model Validation Fig. 3 The energy consumption of node 0 in Fig. 1 evaluated by analytic model and simulation

18. V- ANALYTIC RESULT Fig. 4 The energy consumption of node 2 in Fig. 1 evaluated by analytic model and simulation

19. V- ANALYTIC RESULT Fig. 5 The energy consumption of node 2 in Fig. 2 evaluated by analytic model and simulation

20. V- ANALYTIC RESULT • A grid topology used in analysis S-MAC based WSN design 0 1 0 0 4 0 0 7 8 Fig. 6 A grid topology used in analysis S-MAC based sensor network design

21. V- ANALYTIC RESULT Fig. 7 Relative energy consumption,relative latency and relative energy*delay of total network

22. B. Energy Efficiency of S-MAC • In many sensor network applications, energy consumption is not the only important design issue. • Periodic sleep scheme in S-MAC saves energy while nodes are idle, but this scheme also introduce additional delay for waiting the reviver back to listening from sleeping. • Choosing a shorter duty cycle would decrease the idle listening time, but increase the latency.

23. B. Energy Efficiency of S-MAC Fig. 8 Relative energy consumption of total network of 20 chain-hops.

24. B. Energy Efficiency of S-MAC • According to formula (1),the energy consumption of S-MAC based sensor nodes can be devided into 4 parts: • Sending packets • Receiving packets • Idle Listening • sleeping

25. VI. CONCLUSION AND FUTUR WORK • This paper introduces an analytic model to estimate the energy consumption S-MAC • S-MAC saves energy but sacrifices latency. To achieve better energy efficiency than S-MAC, the future work includes the improvement of energy consumption and reduction of packet latency of S-MAC.