Mohd Amaluddin Yusoff

Design of spectrally efficient ultra-wideband waveforms using Hermite-Rodriguez functions

Spectral efficiency is a major requirement in ultra-wideband (UWB) communication systems because of very low power spectral density (PSD) regulations imposed on the transmitted signals. Besides, large number of orthogonal waveforms is highly desirable in multiuser systems. In this study, the design of a set of spectrally efficient orthogonal waveforms is investigated. The design of UWB waveforms based on orthogonal Hermite–Rodriguez basis functions and linear frequency modulation (LFM) is proposed herein. The design is formulated as a quadratic semi-infinite programming problem with spectral and orthogonality constraints. Numerical examples are presented to illustrate the effectiveness of Hermite–Rodriguez-based waveforms with the proposed optimisation approach. Comparison with a recent result shows that the proposed approach compares favourably with those reported in the literatures in terms of the number of waveforms can be produced and the achievable spectral efficiency of the designed waveforms.

Design of UWB waveforms for narrowband interferences suppression

In this paper, we design a set of orthogonal waveforms which suppresses narrowband interferences (NBI) in ultra-wideband (UWB) communication systems. We use linear frequency modulation (LFM) and Hermite-Rodriguez basis functions. The problem is formulated as a semi-infinite quadratic optimization problem. Computationally efficient approach to solving the optimization problem is proposed. An example of multiple NBIs suppression problem is presented to illustrate the effectiveness of the proposed approach.

Speech processing in FPGA with C-to-RTL compiler technology

In most cases, speech processing algorithms are developed on off-the-shelf microprocessor or DSPs. Recently, the modern FPGA offers virtually unlimited computational resources that can be executed in parallel. Hence, FPGA outperform the DSP in terms of throughput and costs. The design process of FPGA is always considered time consuming and tedious progression. This paper is aimed to explore the technology that shorten the gap between embedded software and hardware, in particular, speech processing in FPGA with C-to-RTL Compiler. Furthermore, The migration and the co-design between software and hardware are also discussed.

UWB waveform set design using Löwdin's orthogonalization with Hermite Rodriguez functions

In this paper we design a set of spectrally efficient orthogonal waveforms based on Hermite Rodriguez functions. The design is formulated as a semi-infinite quadratic programming problem and subsequently Lowdin method is used to generate a set of orthogonal waveforms. This approach is able to produce many overlapping orthogonal waveforms with high spectral efficiency. (4 pages)

Innovative Ultrasonic Sensors-based 2D Keypad Using Chain Code Algorithm

This paper describes an elegant method for recognizing the pattern of alphabets and distinguishing different points and their orientation based on two ultrasonic distance sensors. Sequence of line segments, formed by a set of different points, is determined by chain code algorithm. The result shows the simplicity of the system utilizing ultrasonic sensors, which can be developed into a new type of keypad.

Waveform Set Design Using Hermite-Rodriguez Functions for CDMA Communications

In this paper, we consider the waveform set design for CDMA communications using orthogonal Hermite-Rodriguez basis functions. The waveform set design problem is formulated as a constrained L2 space optimization problem. For bandwidth efficiency, all the waveforms in the set are constrained to have approximately the same desired spectral shapes in a prescribed passband. To minimize intersymbol interference and co-channel interference, all the waveforms in the set are constrained to have low values of autocorrelation and cross-correlation. Numerical results are presented to illustrate the effectiveness of Hermite-Rodriguez functions and the usefulness of the design method to solve the waveform set design problem.