A typical concern of how application can secure the ieee 802. Ofdm physical layer is used in the broadband technology namely fixed wimax and ofdma is used in mobile. Wimax physical layer is based on the orthogonal frequency division multiplexing ofdm. The modulations formats used in evaluating wimax physical layers performance include.
The block diagram of wimax physical layer system is shown in figure 1 6. At the end final conclusion drawn on the basis of the results is given in section vii. The enodeb can estimate the code rate and modulation scheme by using the sounding reference signal srs. Results and simulations are analyzed in section vi. Discussion about physical layer threats to wimax technology and how these threats makes wimax network vulnerable. Experimental evaluation of the wimax downlink physical layer. The original version of the standard on which wimax is based ieee 802.
The model used 56rated convolutional code with qpsk digital modulation and the system performance can be. Simulation of physical layer of wimax network using opnet. A detailed explanation of the proposed wimaxmimo system can be studied in section v. Wimax worldwide interoperability for microwave access is a family of wireless broadband communication standards based on the ieee 802. The noise channel awgn, rayleigh fading, sui, data randomization techniques, fft and ifft, and adaptive modulation is used for the whole simulation procedure. Simulation of wimax physical layer using simulink and matlab is described in 12. Wimax market, technology and early solutions for the. A variety of digital modulation analysis measurements and displays will be covered, and a general structure of signal analysis will be presented. Orthogonal frequency division multiple access is used by wimax on its physical layer. Randomization it is the first process which is carried out in the wimax physical layer after the data packet is received from the higher layers and each of the burst in downlink as well as in the uplink is randomized. This paper discusses the model building of the wimax physical layer. Parameters that have a significant impact on the physicallayer data rate are channel bandwidth and the modulation and coding scheme used. This is the logical point to start in most test regimes.
Performance evaluation of fixed wimax physical layer under. Orthogonal frequency division multiple accesses use adaptive modulation technique such as bpsk,qpsk,16qam,64qam on the physical layer of wimax and it uses the concept of cyclic prefix that adds additional bits at the transmitter end. The radio link is a quickly varying link, often suffering from great interference. This paper discusses the model building of the wimax physical layer using simulink in matlab. Analysis of wimax physical layer using spatial diversity. Pdf a physical layer simulator for wimax in rayleigh fading. Matlab source code for the test vectors and simulink model for physical layer. Ofdm is a combination of glace, simple and effective technique to avoid the multiple path distortions. In this chapter, some elements of the transmission chains of wimax are described for both ofdm and ofdma phys. It is first version and likely to be revised very soon with other features. In this work, however, we succeeded in doing such an experimental evaluation with a lowmobility vehicle. It gives a detailed overview of the basic concepts of wimax fft, ofdm, frame structures, etc and explains the physical standard parts of ieee 802. The main blocks are implemented with the aid of the matlab programming language.
Wimax mac layer is a point to multipoint protocol p2mp. The model used 56rated convolutional code with qpsk digital. Performance evaluation of wimax physical layer using. Exponential effective signal to noice ratio mapping eesm. The physical layer block diagram of wimax transmitter has been described. The wimax physical layer article describes ofdm physical layer of wimax is as per ieee 802. A detailed explanation of the proposed wimax mimo system can be studied in section v. The specific phy technical descriptions are given in the wimax forumt2 documentations or the original ieee 802. All the necessary conditions were implemented in the simulation according to the 802. Simulating the wimax physical layer in rayleigh fading. Wimax market, technology and early solutions for the physical layer kim tran agilent technologies this presentation will cover some of the technical issues and measurements of 802. This thesis also contain implementation of all compulsory features of the wimax ofdm physical layer specified in ieee 802. Simulating the wimax physical layer in rayleigh fading channel.
Channel coding, whose main tasks are to prevent and to correct the transmission errors of wireless systems, must have a very good performance in order to maintain high data rates. Performance evaluation of wimax physical layer using matlab. The tests are described in some detail to allow the reader to appreciate. This task is done by various processing techniques. Topics covered include wimax genesis and framework, wimax topologies, protocol layers, mac layer, mac frames, wimax multiple access, the physical layer, qos management, radio resource management, bandwidth allocation, network architecture, mobility and security. Wimax physical layer the wimax physical layer is based on the orthogonal frequency division multiplexing ofdm, which is the transmission scheme of choice to enable the highspeed data, video, and multimedia communications. I am thankful for all my friends for their encouragement and great memories. The lte physical layer supports two types of frame structures as types 1 and 2. In this paper, the architecture of the wimax physical layer simulator is presented. Bpsk 4qam 16qam 64qam block arrangement to implement this work, it is necessary to first achieve a ber plot of the physical layer of wimax. This application note is one of three papers dealing with the wimax standard, covering the theoretical aspects of wimax. Toward broadband wireless metropolitan area networks yan zhang and hsiaohwa chen isbn. It also defines the type of modulation and demodulation as well as transmission power.
Simulation of physical layer of wimax network using opnet modeller. Physical layer phy test descriptions are focused around the rf connection and start with the transmitter tests in section four. Parameters that have a significant impact on the physical layer data rate are channel bandwidth and the modulation and coding scheme used. Request pdf wimax physical layer wimax air interface is based on a ieee standard emerged from 802.
Mac convergence, mac layer, mac privacy and the physical layer. Ofdm is the transmission scheme of choice to enable highspeed data, video, and multimedia communications and is used by a variety of commercial broadband systems, including dsl, wifi, digital video broadcasthandheld dvb. The physical layer supports many developed techniques for enhancing the reliability of link layer. Analysis of wimax physical layer using spatial multiplexing. One wimax base station can be accessed by more than 60 users. Performance characteristics of an operational wimax network. This is achieved by arranging the necessary blocks appropriately to give the desired result. This paper covers wimax frame and symbol structure and describes physical layer modules and functions of each in brief as per ieee 802. The wimax physical layer is based on the orthogonal. Now we will explain each of the blocks one by one in detail. Wimax model for physical layer the physical layer of wimax is quite flexible. A signicant body of published research in the wimax domain exists, but the focus of much of it is on the use of analytic or simulation models to evaluate aspects of physical layer protocols, medium access control protocols, or proposed scheduling algorithms. The experimental evaluation of the wimax downlink physical layer in highmobility scenarios is extremely difficult to carry out because it requires the realization of measurement campaigns with expensive fastmoving vehicles.
Developing an understanding of the wimax system can be best achieved by looking at a model of the wimax system. Ofdm is the transmission scheme of choice to enable highspeed data, video, and multimedia communications and is used by a variety of commercial broadband systems, including dsl, wifi, digital video broadcasthandheld dvbh, and mediaflo, besides wimax. Wimax stands for worldwide interoperability for microwave access support both fixed and mobile wireless broadband advance features of wimax ofdmbased physical layer high data rate adaptive modulation and coding multipleantenna techniques quality of service support. Data encoding method of converting a stream of data bits into. Wimax physical layer physical layer set up the connection between the communicating devices and is responsible for transmitting the bit sequence. Experimental evaluation of the wimax downlink physical. Further, the physical layer signal processing and as last the model of physical layer in matlab. Pdf a physical layer simulator for wimax in rayleigh.
The last section is dedicated to conclusions and further work objectives. Mac layer wimax equipment trial results future of wimax 8 what is wimax. The wimax physical layer is based on orthogonal frequency division multiplexing. Study of wimax physical layer under adaptive modulation. The type 1 structure is used for frequency division duplex fdd mode. It this paper we describe performance characteristics of an operational wimax. Ofdm is a good choice of high speed data transmission, multimedia communication and digital video services.
In individual parts of this thesis we will have closer look on wimax, multiple access scheme ofdma and ofdm modulation. Jan 12, 2008 the wimax can also be considered to be the main technology in the implementation of other networks like wireless sensor networks. Some simulation results are presentedand commented in section iv. Mobile wimax phy layer rf operation and measurement. The basics of the phy layer in wimax are presented in the proposed simulator is described in section iii. Pdf analysis of wimax physical layer using spatial. This model is based on physical layer specification of ieee 802.
The physical layer of wimax is having a base on ofdm. Although, the implementation of the physical layer inbuilt security enhancement of the cdma system application in 6 used encryption based security known as scrambling. Wimax is a wireless technology which offers high data rate transmission in broadband. Worldwide interoperability for microwave access wimax standard is based on the ieee 802.
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