Networking Group University of Trento http networking disi

Networking Group University of Trento http: //networking. disi. unitn. it SESAM: A Semi -Synchronous, Energy Savvy, Application-Aware MAC Renato Lo Cigno, Matteo Nardelli DISI, University of Trento, Italy Michael Welzl Institute of Computer Science, University of Innsbruck, Austria

Outline TRITon Project n Energy consumption n Mac Protocol in WSN n SESAM n Future work n Conclusion n Networking Group University of Trento http: //networking. disi. unitn. it

TRITon is a research and innovation project funded by the project members and the Autonomous Province of Trento (Provincia Autonoma di Trento, PAT) aimed at advancing the state of the art in the management of road tunnels, specifically to improve safety and reduce energy costs. An example application, central in TRITon, is adaptive lighting. In current deployments, the light intensity inside the tunnel is typically regulated based on design parameters and the current date and time, and regardless of the actual environmental conditions. Web Site: http: //triton. disi. unitn. it/ Networking Group University of Trento http: //networking. disi. unitn. it

In TRITon, the light intensity inside the tunnel will instead be regulated through a wireless sensor network (WSN). To bring state-of-the-art research and technology like WSN into road tunnel management, the traditional lab-centered research is not sufficient. Indeed, TRITon will transfer its results in real test-sites, four operational tunnels on road SS 45 bis near Trento. This will provide not only the ultimate test for the project outcomes, but also a direct and measurable benefit to the local population. Networking Group University of Trento http: //networking. disi. unitn. it

Outline TRITon Project n Energy consumption n Mac Protocol in WSN n SESAM n Future work n Conclusion n Networking Group University of Trento http: //networking. disi. unitn. it

Energy consumption Energy efficiency is one of the primary concern in a wireless sensor network expecially if the sensors are located in unfriendly environment like a road tunnel Low level MAC Idle power In Table we report the typical consumption value of a WSN node 802. 15. 4 1 μW Sense power 30 m. W Rx power 60 m. W Tx power 25 to 50 m. W Total energy consumption per node per day 600 Bench-MAC 0. 2 pck/min Bench-MAC 1. 0 pck/min Bench-MAC 5. 0 pck/min Energy [J] 500 Graph rappresent the energy consumption with different transmission rate 400 300 200 100 0 2 4 6 8 10 12 14 16 18 20 No. of stations Networking Group University of Trento http: //networking. disi. unitn. it

Energy consumption per day for each function; 1 pck/min 100 Bench-MAC Tx Bench-MAC Rx Bench-MAC Sense Energy [J] 80 60 40 20 0 2 4 6 8 10 12 14 16 18 20 No. of stations Networking Group University of Trento http: //networking. disi. unitn. it

Energy consumption Networking Group University of Trento http: //networking. disi. unitn. it

Outline TRITon Project n Energy consumption n Mac Protocol in WSN n SESAM n Future work n Networking Group University of Trento http: //networking. disi. unitn. it

Mac Protocol An extensive amount of work has been done on energy conserving MAC protocols. Existing approaches can be categorized as synchronous and asynchronous, although there are some hybrids. Synchronous: SMAC Asynchronous: BMAC PROS • periodic listening; • Low Power Listening (LPL) • collision avoidance; • Scalability • overhearing avoidance. CONS • preamble is longer than sleep period; • Nighbors synchronization • overhearing. • Sleep and listen period is predefined and constant • Complex implementation Networking Group University of Trento http: //networking. disi. unitn. it

Outline TRITon Project n Energy consumption n Mac Protocol in WSN n SESAM n Future work n Conclusion n Networking Group University of Trento http: //networking. disi. unitn. it

SESAM is a distributed MAC protocol, which, making use of application level information to predict future transmission instants between nodes. Our goal is: • Useless (re)-trasmissions; • receiving packets which are not for the node; • sensing the channel without need. Constraints are: • No global coordination, but only pairwise (i, j) implicit signaling; • Self-bootstrapping properties for new nodes entering the system and for the activation of a new traffic relation. Networking Group University of Trento http: //networking. disi. unitn. it

SESAM The system is based on low-level real time MAC functions able to do CSMA and generate acknowledgments. Elementary coordination for a single relation: Networking Group University of Trento http: //networking. disi. unitn. it

SESAM Housekeeping periods: Networking Group University of Trento http: //networking. disi. unitn. it

Result We compared SESAM with two version of a B-MAC like protocol. For all protocol we consider acknowelged transmission and absence of collision avoidance procedures Bench. MAC-0: Upon plain CDMA we insert a low power listening (LPL) functionality which enables nodes to sleep most of the time, and wake up periodically to sample the channel status; Bench. Mac-1: This is the 1 -persistant version of the protocol. The different with the Bench. MAC-0 are: if the channel is sensed busy the node wait until the trasmission ends and immediatly transmits the packet and all other nodes must keep sensing the channel after the end of a packet trasmission. Networking Group University of Trento http: //networking. disi. unitn. it

Result Total energy consumption per node per day 600 SESAM Banch. MAC 1 -P Banch. MAC 0 -P rate: 2 pck/min rate: 1 pck/min rate: 0, 5 pck/min 500 Energy [J] 400 300 200 100 0 2 4 6 8 10 12 14 16 18 20 No. of Station Networking Group University of Trento http: //networking. disi. unitn. it

Result Packet Lost for 10 station 100 τlp = 500 ms % Packet lost 80 60 Banch. MAC 0 -P Banch. MAC 1 -P 40 SESAM τlp = 50 ms 20 0 10 20 30 60 90 120 150 180 210 240 Packet/min Networking Group University of Trento http: //networking. disi. unitn. it

Outline TRITon Project n Energy consumption n Mac Protocol in WSN n SESAM n Future work n Conclusion n Networking Group University of Trento http: //networking. disi. unitn. it

Multi-housekeeping domain The most critical working conditions for a CSMA base WSN are with a wide area coverage using the same frequency channel Networking Group University of Trento http: //networking. disi. unitn. it

Multi-housekeeping domain - bootstrapping Power on Sensing channel Send msg. ACK to HK Y rx msg? Packet format: NEW HK = (ID node, HK domain, τ, NEW) ACK HK = (ID node, ID node sender, HK, τ, ACK) N end N sense? Y Send msg. NEW HK Syncro. to one or multi HK Networking Group University of Trento http: //networking. disi. unitn. it

Outline TRITon Project n Energy consumption n Mac Protocol in WSN n SESAM n Future work n Conclusion n Networking Group University of Trento http: //networking. disi. unitn. it

Conclusion Networking Group University of Trento http: //networking. disi. unitn. it