1. Enhancement of the S-MAC Protocol for Wireless Sensor Networks Faisal Hamady Mohamad Sabra Zahra Sabra Ayman Kayssi Ali Chehab Mohammad Mansour IEEE © 2010 Review paper khadijah salim bahwaireth KHADIJAH SALIM 435803601

2. WSN consist of nodes connected together to fulfill their task; these nodes have limited power resources. The primary issue of these sensor networks is the energy efficiency. Introduction KHADIJAH SALIM 435803602

3.  1- Random: there is no coordination between nodes, the wake and sleep periods occur in random intervals. The disadvantages are waste of energy because the node wakeup when no transmission occur, and collisions between nodes. Example : B-MAC. MAC Protocols KHADIJAH SALIM 435803603

4.  2- Slots: all nodes wakeup and sleep at the same time, need synchronization between nodes. example of these protocols is S-MAC, there is more collision between nodes.  3- Frames: here nodes do transmission in specific time slot, as in TDMA protocol. KHADIJAH SALIM 435803604

5. S-MAC Protocol KHADIJAH SALIM 435803605 S-MAC protocol is a medium access control protocol that is widely used in WSNs for energy conservation. The nodes alternating between fixed listen and sleep period according to its schedule(see Fig. 1).

6. S-MAC Protocol KHADIJAH SALIM 435803606 S-MAC allows neighboring nodes form virtual cluster by agree the same schedule, so these nodes sleep and wakeup at the same time. The node randomly choose a time to go to sleep. The node receives and follows its neighbor’s schedule by setting its schedule to be the same. If the node receives a different schedule after it select its own schedule, it adopts both schedules, this node consume much more power and called intermediate node or border node

7. S-MAC problem KHADIJAH SALIM 435803607

8. 8 SIN PROTOCOL  In SIN protocol, when the border node receives a schedule from announced node, it is decide based on its schedule status  a)if the node does not have any schedule, it is immediately accept the announced schedule.  b) if the node already has a schedule, when receiving an announced schedule, it will send a unicast packet (request) for announced node asking for a permission to follow announced schedule, Once the announced node receive these requests its replies to selective number of border nodes with Ack packets, Only nodes that receive Ack packets it follow both schedules.

9. S-MAC enhancement (SIN) KHADIJAH SALIM 435803609

10. S-MAC enhancement (SIN) KHADIJAH SALIM 4358036010 Shortly, we can say the border node is accept the announced schedule only, if it is receiving an acknowledgment from an announced node. As a result, the number of border node that following multiple schedules are decreased, and the energy- consumption also decreased.

11. Performance Evaluation: KHADIJAH SALIM 4358036011

12.  The life-time of nodes enhanced 11% to 13%.  And the battery efficiency for each node increased by a factor of 1.42. KHADIJAH SALIM 4358036012

13. Performance Evaluation: KHADIJAH SALIM 4358036013

14. The authors present a proposed protocol SIN, this protocol saving energy and enhancing the life time of battery by reducing the intermediate nodes. Therefore, the SIN protocol is designed and responsible for under moderate traffic rate. Conclutions KHADIJAH SALIM 4358036014