Achieving optimal design of phase-locked loop (PLL) is a major challenge in WiMax technology in order to improve system behavior against noise and to enhance Quality of Service (QOS). A new loop filter design method for phase locked loop (PLLs) is introduced taking into consideration various design objectives: small settling time, small overshoot and meeting Mobile WiMax requirements. Optimizing conflicting objectives is accomplished via linear programming and semidefinite programming (especially Linear Matrix Inequality (LMI)) in conjunction with appropriate adjustment of certain design parameters. Digital filters, Infinite Impulse Response (IIR) and Finite Impulse Response (FIR) are designed using linear programming and convex programming.Simulations show that IIR digital lowpass filter with narrow transition band could not work properly with mobile WiMax system. Simulations show that FIR digital lowpass filter utilizing linear programming managed to improve the transient behavior. The FIR digital lowpass filter utilizing semidefinite programming (LMI) will much improve the transient behavior; therefore it is recommended for mobile WiMax systems.
Achieving an optimal design of phase-locked loop (PLL) is a major challenge in WiMAX technology in order to improve system behavior against noise and to enhance Quality of Service (QoS). A new loop filter design method for PLL is introduced taking into consideration various design objectives such as small settling time, small overshoot and meeting Fixed WiMAX requirements. Optimizing conflicting objectives is accomplished using semi-Definite programming (especially Linear Matrix Inequality (LMI)) in conjunction with appropriate adjustment of certain design parameters. Infinite Impulse Response (IIR) and Finite Impulse Response (FIR), Digital filters are designed by Semi-Definite Programming (SDP) using SeDuMi (self-dual minimization) toolbox software. Design efficiency and performance of the proposed method are illustrated by simulations and comparisons to other design methods. Simulations showed that the IIR which was designed by SDP is better than the IIR which designed by Linear Programming (LP).Also, the FIR which was designed by SDP using SeDuMi software is better than the FIR which was designed in by SDP using CVX (convex optimization tool) software.
Telecommunication industries are highly concerned with the wireless transmission of data which can use various transmission modes, from point- to-multipoint links. It contains full mobile internet access. Various applications have already been applied so far using WiMAX, as alternative to 3G mobile systems in developing countries, Wireless Digital Subscriber Line, Wireless Local Loop . IEEE 802.16e-2005 has been developed for mobile wireless communication which is based on OFDM technology and this enables going towards the 4G mobile in the future. In this thesis work, we built a simulation model based on 802.16e OFDM-PHY baseband and demonstrated in different simulation scenarios with different modulation techniques such as BPSK, QPSK and QAM (Both 16 and 64) to find out the best performance of physical layer for WiMAX Mobile. All the necessary conditions were implemented in the simulation according to 802.16e OFDMA-PHY specification. The noise channel AWGN, Rayleigh fading, SUI, data randomization techniques, FFT and IFFT, and Adaptive modulation is used for the whole simulation procedure. Performance has been concluded based on BER, SNR and Pe output through MATLAB Simulation.
In this project, Verilog HDL is used for the implementation due to its compatibility with pure digital hardware like FPGA’s. The Digital PLL is simulated and verified on FPGA to experience its advantages. The circuit comprises of a phase detector, loop filter, Numerically Controlled Oscillator (NCO), and two clock dividers. The circuit was stabilized to produce the frequency in the audio frequency range of 9.7 KHz. This agreed with the classical phase-locked loop model for the system. The stable long-term frequency clock was verified on the FPGA to generate the required locking frequency. The DC logic synthesis and a new synopsis low power flow was experimented for back annotation and to obtain the maximum possible operating frequency and area, timing and power estimation.
A phase locked loop (PLL) plays significant role in analog and digital systems. It is a control system that generates an output signal in-phase of the input reference signal. This report has presented a low-power PLL implemented in 130nm CMOS technology for communication systems. The improved power efficient design of PLL consists of a phase detector; a charge pump, low pass filter, and bulk driven three stage ring VCO. The VCO is the main part PLL design. The proposed three, five and seven stages ring VCOs are presented in this report. The proposed three stage ring VCO shows better performance in terms of tuning range (917.43 MHz-4189.53 MHz) and power consumption (14.67µW). The output frequency of VCO shows almost linear relationship with the control voltage. The key design objectives of PLL are size, power consumption, lock range and frequency range of the VCO. The proposed low power, small area PLL has great potential in implantable bio-medical and wireless systems.
I am proud to present my book which I believe will prove as a milestone in various engineering projects. My aim is to design and fabricate an industrial system communicating between two stations connected wirelessly via WiMAX. It covers all the technical details and focuses on its application in various industrial processes. WiMAX is an emerging technology which is gaining ground these days. The reason for publishing such a book is to cater for today’s growing needs of automation in industries. Monitoring instruments and sensors wirelessly is today’s demand. It decreases cabling costs and installation time and is ideal in electrically noisy or hostile environments. It can decrease human intervention by making the machinery automatic, save the operator from tedious job of continuous monitoring and avoid unauthorized usage hence increasing the accuracy and security of the system. It also covers the future applications of WiMAX e.g. Cellular networks, Broad-band access etc. I therefore conclude that this book is not specifically for industrial automation rather it can be considered as a powerful tool that formulates the basic building block of the wireless technology WiMAX.
This book presents an innovative approach to detect computational fault using design for testability (DFT) of CP-PLL (charge pump phase locked loop) to allow simple digital testing. The proposed structure is useful in mixed signal IC (incorporating both analog and digital block on the same chip) testing. With increasing complexity of mixed signal IC the demand of preparing the low cost testing circuitry also gets increased. Here CP-PLL is taken as the mixed signal IC wherein the proposed method uses the charge pump as stimulus generator and the VCO (voltage controlled oscillator) as measuring device for testing the CP-PLL. It avoids the need of interfacing any foreign component and decreases the area overhead of whole IC. Moreover, testing circuitry is applied at the digital part of the CP-PLL i.e. PFD (phase frequency detector) and the analog part i.e. charge pump; loop filter and VCO are controlled by PFD only. Consequently the efficiency of the testing process avoiding the loading effect at analog node is increased. Fault simulation results indicate that the proposed structure posses high fault coverage of 98.2% and less area overhead of about 3.025%.
WiMAX technology is currently the advanced technology in the world but the WiMAX physical layer has no control over the dynamic channel. For error correction, parity bits which are appended with the data bits are the over head which if the poor channel conditions arise, degrades the performance of the system extremely. Due to this fact the WiMAX equipment is defenseless against the unpredictable non linear change in the received signal. Using bit loading algorithms will result in minimizing the effect of channels which further facilitates the transmission. Bit-loading is a very dominant technique for transmission over frequency-selective fading channels. Further reduction in BER performance of the system can be achieved. The performance of the WiMAX system is tested with the bit-loading algorithms. The two algorithms Chow and Campello together develop an effective method for further minimizing the bit-error-rate of a WiMAX system. The adaptive bit loading techniques estimates the channel. With the help of this information an efficient strategy is incorporated to synchronize with the channel. It provides some consistency in the wireless channel.
In cellular mobile communication, since there will be conversation in progress in case of handover calls, GOS for them should be less than that for newly originating calls. Basically, there are three channel assignment schemes, fixed, dynamic & hybrid channel assignment schemes for handling newly originating and handover calls. In this study, capacity design for cellular mobile network in area inside ring road in Kathmandu valley has been done according to the findings of data collection and analysis of mobile communication service being provided by Nepal Telecom. Capacity planning has been done with GOS equal to 2% for newly originating calls and 1% for handover calls. In addition to capacity planning, efficient channel assignment scheme in terms of blocking and throughput has been evaluated with optimal utilization of the designed capacity for getting minimum blocking for both types of calls maintaining the blocking for handover calls always less than that for newly originating calls. The simulated values of GOS & throughput for all channel assignment schemes at different penetration have been compared and hybrid channel assignment scheme has been found to be most efficient.
In modern control systems, physical plant, controller, sensors and actuators are difficult to be located at the same place, and hence these components need to be connected over network media. When feedback control system is closed via a communication channel, then the control system is classified as a Networked Control Systems (NCS). This book presents the design of dissipative control system for NCS. The dissipativity analysis with quadratic supply function is quite general which includes H? and passivity as special cases. The NCS is modelled as a time delay systems. Two network features are considered: signal transmission delay and data packet dropout. Our objective is focused on the design of state feedback controller which guarantee asymptotic stability of the closed-loop systems. The proposed methods are given in the terms of Linear Matrix Inequality (LMI). If this LMI conditions feasible, a desired controller can be readily constructed. Finally, we consider an unstable system for systems simulation. It is shown that the state feedback controller proposed here make the closed-loop system stable with or without input disturbance.
Modern cellular phones and base stations have to serve a multitude of wireless communication standards with each standard using different frequency bands. For such applications, a universal programmable hardware is desirable which is often referred to as software-defined radio (SDR). This book describes agile frequency synthesizers representing key building blocks for an SDR transceiver. In this work, an innovative frequency generation scheme is derived to provide a multi-octave tuning range with very low phase noise and low spurs. A PLL phase noise model including a nonlinear phase detector is thoroughly discussed. Design techniques for low phase noise VCOs with mixed analog/digital tuning are presented. Further, the book investigates both single-loop and dual-loop PLL architectures in fractional-N synthesizers. An unconventional two-transistor based charge pump in a dual-loop PLL improves phase detector linearity and reduces charge pump noise. This results in a low in-band phase noise similar to an integer-N synthesizer. Finally, the book presents the design of fully integrated integer-N and fractional-N frequency synthesizers with detailed measurement results.
High-performance digital systems use clocks to sequence operations and synchronize between functional units and between ICs. Clock frequencies and data rates have been increasing with each generation of processing technology and processor architecture. Phase locked-loops (PLLs) are widely used to generate well-timed on-chip clocks in high-performance digital systems. A PLL is a closed loop frequency system that locks the phase of an output signal to an input reference signal. PLL‘s are widely used in computer, radio, and telecommunications systems where it is necessary to stabilize a generated signal or to detect signals. The term lock refers to a constant or zero phase difference between two signals. The signal from the feedback path is compared to the input reference signal,until the two signals are locked. If the phase is unmatched, this is called the unlocked state, and the signal is sent to each component in the loop to correct the phase difference. These components consist of the Phase Frequency Detector (PFD), the charge pump (CP), the low pass filter (LPF), the voltage controlled oscillator (VCO) and divide by counter.
With the development in internet applications and multimedia technology, users are accustomed to high-speed broadband at home and work and demand similar services even in nomadic or mobile environment. Mobile WiMAX provides broadband wireless access with mobility, large coverage and security. WiMAX physical layer is based on Orthogonal Frequency Division Multiplexing which mitigates multipath and eliminate intersymbol interference with the help of cyclic prefix. Scalable OFDMA on its physical layer allows data rate to scale with available channel bandwidth. WiMAX supports a number of modulation (BPSK, QPSK, 16-QAM & 64-QAM) and forward error correction coding scheme and can operate in both line of sight and non-line of sight environments. In this book, the performance of physical layer of mobile WiMAX is evaluated at different modulation schemes, coding rate, FEC coding schemes and noise levels with models of multipath fading channel based on the specification of IEEE Std. 802.16-2009. Scatter plots and SNR vs BER plot are obtained as performance analyzer. GUI tool is developed in MATLAB for simulation which can be useful for research scholar to simulate physical layer of WiMAX
The IEEE 802.16m standard of the Worldwide Interoperability for Microwave Access (WiMAX) was accepted as a 4G standard in 2011. The IEEE 802.16m is fully optimised for fixed wireless communication environments and can deliver very high throughput and excellent quality of service. However, in mobile communication environments the WiMAX quality of service experiences a graceful degradation as a direct function of the speed of mobile nodes. Unless some proactive measures such as forward error control and packet size optimisation are adopted and properly adjusted, many applications cannot be supported in WiMAX at high vehicular speeds. Bit error estimation as a function of vehicular speeds serves as a useful tool for any proactive measure. This book presents an analytical model for bit error estimation in WiMAX communications using the Nakagami-m fading model. This book also shows that the Nakagami-m model can be made adaptive as a function of speed to represent fading in a fixed environment as well as in a mobile environment.