RAYLEIGH FADING NETWORKS: A CROSS-LAYER WAY Abstract In this paper we are going to deal with, wireless ad-hoc and sensor networks over Rayleigh fading channels. First, we will model Rayleigh fading networks and show how to map the wireless fading channel to the upper layer parameters for cross-layer design. Based on the developed fading network model, we will consider two scarce resources of wireless networks, namely energy and medium, and develop a cross-layer way to improve their efficiency. In particular, we will first study the energy-efficiency and introduce a new parameter, Energy Cost Factor, as the counterpart of Transport Capacity in wireless transmission. The new parameter will be used to design energy-efficient networks. As to the medium resource, we will bring forward the Medium Resource Space, which not only organizes various medium resources in a systematic way but also considers a third dimension related to space reuse and internode interference. Finally, we will give a general discussion on the cross-layer design and show how power control and route selection jointly contribute to improving the resource efficiency. A few particular routing algorithms will also be studied in detail. BLOCK DIAGRAM R.F. SOURCE GAUSSIAN NOISE SOURCE GAUSSIAN NOISE SOURCE (pi/2) PHASE SHAPING SHIFTER FILTER SHAPING FILTER BALANCED MODULATOR BALANCED MODULATOR ADDER RAYLEIGH FADING R.F. SIGNAL EXISTING SYSTEM Rayleigh fading channel:Rayleigh fading is a statistical model for the effect of a propagation environment on a radio signal, such as that used by wireless devices. Rayleigh Fading Channel is a statistical model of the communication channel through which a radio signal propagates. It is composed of three words Rayleigh- It Corresponds to the Rayleigh Distribution in Continuous Probability Distribution. Fading - It means degradation of signal due to different objects in the environment. Channel: It corresponds to medium which is used for delivering the information. Therefore, it means that when a radio signal passes through a communication channel the power of the signal will vary according to Rayleigh distribution. An ad-hoc wireless network is a collection of wireless nodes that self organize into a network without the help of an existing infrastructure. Some or possibly all of these nodes are mobile. Since the network can be deployed rapidly and flexibly, it is attractive to numerous potential applications, ranging from multi-hop wireless broadband Internet access to highway automation to voice and video communications for disaster areas. DISADVANTAGES 1. In energy aware routing algorithms, the total energy consumption of a whole multi-hop route is used as the criterion, which typically requires central control 2. Energy is widely recognized as a scarce resource in wireless . Owing to the lack of well-matched physical models, the energy consumption functions adopted by previous works are usually inaccurate PROPOSED SYSTEM The concept of Transport Capacity is one which takes the distance between the source and destination into account in measuring the traffic load. This concept unveils the fundamental difference between wireless and wired transmissions, and inspires our definition of the new parameter Energy Cost Factor for measuring energy efficiency. We will illustrate this new measure with a few practical design examples and show how to design energy efficient networks by optimizing the proposed Energy Cost Factor. Medium resource or radio bandwidth is another scarce resource in wireless networks. Compared with point-to-point wireless link, the medium resource in wireless networks is more elusive. This is largely due to two highly related phenomenon’s in medium access, namely space reuse and internodes interference. Space reuse expands the medium resources by reuse channels at separated locations, while internode interference limits the degree of space reuse. But how to measure the medium resource extension due to space reuse and how to make use of it efficiently are still open problems. In this paper, we will bring forward the concept of Medium Resource Space, which not only organizes various resources in a systematic way but also considers the third dimension related to space reuse and internode interference. Based on the discussion on Medium Resource Space, we will further study how to design medium-efficient networks. It is widely acknowledges that the design of wireless fading networks should follow a cross-layer way. For instance, as will be shown in this paper, the route selection on the network layer plays an important role in determining the energy and medium consumption. Meanwhile, wireless networks are constrained by different factors, which leads to different design goals. As discussed above, energy and medium are two scarce resources in wireless networks, which should be exploited with caution. In light of these, we will give a general discussion on the cross layer design of wireless fading networks, and show how power control and route selection jointly contribute to improving the resource efficiency. Though, the energy-efficiency and the medium-efficiency are not compatible all the time, both of them can be improved by the same procedure, which demonstrates a cross-layer way. ADVANTAGES 1. The physical and MAC layer knowledge of the wireless medium is shared with higher layers, in order to provide efficient methods of allocating network resources 2. Cross-layer optimization is the escape from the pure waterfall-like concept of the OSI communications model with virtually strict boundaries between layers. 3. This enable the compensation for overload, latency or other mismatch of requirements and resources by any control input to another layer but that layer directly affected by the detected deficiency DOMAIN COMMUNICATION Wireless communication is the transfer of information over a distance without the use of electrical conductors or "wires". The distances involved may be short (a few meters as in television remote control) or long (thousands or millions of kilometers for radio communications). When the context is clear, the term is often shortened to "wireless". Wireless communication is generally considered to be a branch of telecommunications. SOFTWARE REQUIREMENT Matlab 7.0 and above MATLAB MATLAB is a high-performance language for technical computing. It integrates computation, visualization, and programming in an easy-to-use environment where problems and solutions are expressed in familiar mathematical notation. Typical uses include: Math and computation Algorithm development Modeling, simulation, and prototyping Data analysis, exploration, and visualization Scientific and engineering graphics Application development, including Graphical User Interface building MATLAB is an interactive system whose basic data element is an array that does not require dimensioning. This allows you to solve many technical computing problems, especially those with matrix and vector formulations, in a fraction of the time it would take to write a program in a scalar non-interactive language such as C or Fortran.