Survey on wireless sensor networks:
Many recent advancements which took place in the wireless communications and electronics is the reason which enabled development of cost effective sensors, and those sensors are used for various applications like in household, military and other areas. The networks still have some technical problems which still need to be fixed and are currently being researched.
Primarily a wireless sensor network is a group of spatially spread sensors which are deployed to monitor and record the physical condition of the environment and also gather data like temperature, humidity, atmospheric pressure, sound and etc. The wireless sensor networks consist a few hundred to ...view middle of the document...
For this reason the designing of physical layer has major importance.
Data Link Layer:
Multiplexing of data streams, data frame detection, error control and medium acces is done in the data link layer. Point to point and point to multipoint connections are made reliable in this layer. Medium Access Control protocol in the wireless multihop network is to self organize sensor networks, where network infrastructure is created and share communication resources efficiently between sensor nodes. MAC schemes which are demand based are not well suited for sensor networks as they have bigger message overhead and link setup delay. For this reason a few more MAC protocols were proposed
• Self Organizing Medium Access Control Sensor Networks and the Eaves drop and register algorithm : The channel access mode here is fixed allocation of duplex time slots at fixed frequency and the sensor network specifies exploitation of large available bandwidth compared to sensor data rate. It has high power consumption.
• Hybrid TDMA/FDMA: It has centralized frequency and time division channel access mode. Optimum number of channels are calculated for minimum system energy. Power consumption is not too high nor too low.
• CSMA based MAC protocol: Contention based random access channel access mode is used here. It has amplification phase shift and pre-transmit delay, and the power consumption is low.
Network Layer :
The network layer provides inter-networking with external networks like sensor networks, control systems and the internet. The sink nodes can also be used as gateway to the other networks. Few design principles used for the network layer are
• Power efficiency
• sensor networks should be data centric
• attribute based addressing and location awareness
This layer is...