Sensing is a technique used to gather information about a physical object or process, including the occurrence of events (i.e., changes in state such as a drop in temperature or pressure). An object performing such a sensing task is called a sensor. For example, the human body is equipped with sensors that are able to capture optical information from the environment (eyes), acoustic information such as sounds (ears), and smells (nose). These are examples of remote sensors, that is, they do not need to touch the monitored object to gather information.
A group of sensor nodes work collaboratively to perform a common application.
• In many WSN applications, the sensor nodes are battery driven and they are often very difficult to recharge or change the batteries.
• Prolonging network lifetimeis a critical issue.
• Sensors often have long period between transmissions (e.g., in seconds).
• Thus, a good WSN design needs to be energy efficient.
Devices are capable of detecting change:
• Temperature
• Pressure
• Humidity
• Sound
• And Many more …
Network Design Challenges
• Limited Energy Capacity
• Limited Hardware Resources
• Massive and Random Deployment
• Dynamic and Unreliable Environment
• Diverse Applications
Figure (1) shows a typical wireless sensor network setup with central monitoring.
Figure 1: A typical view of WSN with central monitoring
The protocol stack for WSNs consists of five protocol layers: the physical layer, data link layer, network layer, transport layer, and application layer, as shown in Figure 2 .
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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