In recent years, with the rapid development of communication and sensor technologies, Wireless Sensor Networks (WSN) are emerging in many industrial and consumer area.
(WSN) is a group of static sensor nodes which gather information and deliver to the base station. In WSN sensor nodes deployed to monitor various physical and environmental parameters. Due to fast development in mobile Internet technology, mobile wireless sensor network (MWSN) has become a popular field of research and replacement of static WSN.
MWSN is a collection of mobile sensor nodes that aim to sense data from the environment and effectively deliver the base station.
Wireless Sensor Environments
Wireless sensor network (WSN) is a developing technology that improves the resource utilization in various fields such as home automation, e-health, smart grid, precision agriculture etc. It consists of sensor devices, which works autonomously with its sensing, communication and computation capabilities. In most of the sensor network applications the nodes will be deployed in remote areas, so replacing the battery often is impossible in many WSN scenarios. Hence energy is considered as a valuable resource in resource constrained wireless sensor networks.
WSN communication suffers from various problems with Self-organization nodes, and environment obstacles. To ensure the best performance of network it is necessary to try to solve the problems of unreliability of links, and to avoid successive retransmission of packet in order to reduce the energy consumption at each node to its task of routing in other words minimizing the route failed re-selection.
Consequently, the evaluation specifies the quality of link, minimize the errors and make the interchangeability between nodes more effective to solve the problems imposed by the unreliability of links. To overcome these problems of layers modules, most researchers proposed cross layer design.
The aim of Cross-layer design is to improve the performance of all layers and share key parameters between these layers.
Whole system performance can be improved if the MAC can get parameter from the PHY about when and how the noise level is changing, as a result the MAC can schedule transmission during the periods of time in which noise levels are lower.
All protocols proposed in WSN have to take in their account the basic inherent characteristics of the network which are: dynamic topology, variable link capacity and bandwidth constraints, energy constraints nodes and multi-hop communications. All these characteristics are seriously challenged the OSI layer design which is characterized by the modularity (Kawadia & Kumar,2005), and permit to create a new methodology named Cross-layer. Cross-layer design refers to an optimized approach design done by allowing layers to exchange state parameter in order to obtain performance gains. The sharing of parameter enables each layer to have global pictures of the constraints and characteristics of the network. Basically, the cross-layer design enables the network protocols and the applications to observe and respond to the changing networks and channel conditions (Rappaport & al,2002).
We can classify the shared parameter of layers as:
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Physical Layer Parameters (PLPs): By focusing on the effects of link quality, power control, a harmonization between Mac and physical layer is investigated. For example, given the current channel state condition, the MAC protocol may adjust some parameters in order to reduce the energy consumption.
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Mac Layer Parameters (MLPs): The link layer has notification mechanisms in case of absence of the acknowledge packet or the clear to send (CTS) packet which permit the network protocols to research newer routes and update their routing table.
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Network Layer Parameters (NLPs): In the route discovery process the network layer can use the parameter of the receive signal strength to choose reliable links to form stable routes by monitoring the signal quality to judge whether the neighbors are approaching or leaving (B Ramachandran & S Shanmugavel, 2008).
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The session layer parameters (SLPs), the transport layer parameters (TLPs) and the application layer parameters (ALPs) of the OSI model are not considered in our work.