wireless sensor networks

May 16 • General • 2533 Views • 5 Comments on wireless sensor networks

Introduction of wireless sensor networks  :

In the wireless sensor networks WSN, Synchronous approaches share the schedule information that specifies the cycle of active and sleep period by the packets of control . On  other hand, asynchronous approaches do not exchange the synchronization information to  receive  or send data. Instead, they employ preamble sampling to do. In the  paper, we compare and analyze synchronous and asynchronous MAC protocols for WSNs or wireless sensor networks  with our two proposed schemes that is AD-MAC and AS-MAC . proposed schemes present an enhanced adaptive duty cycling and high low power listening algorithm for efficiency energy, respectively. The performance of those two MAC mechanisms with our proposed protocols will be investigated through simulation and analysis to design the effective MAC protocol in WSNs or wireless sensor networks.

Nodes in the wireless sensor network WSN  must typically operate unattended for long periods of time on limited battery capacity, and idle listening is a most significant sources of energy consumption in sensor nodes. In idle listening, where the node waits with its radio turned on, listening for a possible packet to be received even though none has been sent. Many solutions to that  problem of idle listening has been proposed utilizing the technique of duty cycling . In this technique, each sensor node normally  turns its radio on only periodically and alternating  between active and states of sleeping . For example  with  duty cycle 10% , a node has its radio on only 10% of the time, resulting in substantial energy savings. In the active state , a node is able to receive and  transmit  data, but in the state of sleeping , the node completely turns off its radio to save energy.

RELATED WORK

The idea of the  receiver-initiated transmission in a MAC protocol is not new, but we make the first attempt to combine this idea together with duty cycling in  context of MAC protocols for ad hoc wireless sensor networks, at where power efficiency is  major concern. Garcia-Luna-Aceves et al. proposed a receiver-initiated collision avoidance scheme for general wireless networks, where collision is the primary concern but the importance is of power efficiency. DATA Frame Transmissions from Contending Senders .The challenges in controlling transmissions from an not-predictable twofold number of contending senders:

• minimize the active time of  receiver for power efficiency;

• minimize the cost for the collision detection and recovery of lost the  data and whether or not the senders are hidden to each other.

To meet these goals in RI-MAC, a receiver employs beacon frames for the  coordination DATA frame transmissions from contending senders. The BW field in a beacon specifies the size  of back-off window senders should use when they contend for the medium. If a received beacon does not contain a BW field (i.e., a base beacon), senders for this receiver should start transmitting DATA without backing off.

EVALUATION

We evaluated the RI-MAC in the  network simulator and in an implementation in TinyOS on MICAz motes. We use simulations to explore the  RI-MAC’s performance in wide variety of networks, especially large network topologies which are hard to deploy and experiment with. As a protocol may not perform in the real world exactly as it does in simulation, for example due to the simplified physical layer models used , we also can  evaluated RI-MAC in the small test bed network of MICAz motes running Tiny OS that is our experimental results match our results obtained and further verify RI-MAC’s performance advantages over existing protocols.

Question answer :

Q1:  What are the  challenges in handling transmissions from an unpredictable number of contending senders?

Ans: • minimize the active time of a receiver for power efficiency,

• minimize the cost for collision detection and recovery of lost data, whether or not senders are hidden to each other.

Q2:  What is actually wireless sensor networks WSN or wireless sensor network ?

Ans: In the wireless sensor networks WSNs or wireless sensor networks , Synchronous approaches share the schedule information that specifies the cycle of active and sleep period by the packets of control . On  other hand, asynchronous approaches do not exchange the synchronization information to  receive  or send data. Instead, they employ preamble sampling to do. In the  paper, we compare and analyze synchronous and asynchronous MAC protocols for WSNs with our two proposed schemes that is AD-MAC and AS-MAC . proposed schemes present an enhanced adaptive duty cycling and high low power listening algorithm for efficiency energy, respectively. The performance of those two MAC mechanisms with our proposed protocols will be investigated through simulation and analysis to design the effective MAC protocol in WSNs.

Q3: What are the Simulation Radio Parameters give 2 example?

Ans: Bandwith, slot time

Q4: What are the Simulation MAC Protocol Parameters give 2 example?

Ans: Special Frame Size , Dwell Time.

Q5:  What we evaluated from this?

Ans:  We evaluated the RI-MAC in the  network simulator and in an implementation in TinyOS on MICAz motes. We use simulations to explore the  RI-MAC’s performance in wide variety of

networks, especially large network topologies which are hard to deploy and experiment with. As a protocol may not perform in the real world exactly as it does in simulation, for example due to the simplified physical layer models used ,

questions on wireless sensor networkswireless sensor networksWSN

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