ABSTRAKSI: This final project will show the simulation of human blood circulation velocity by using Integrated-optic Doppler Velocimeter. The measurement and visualization will be using the MAT-LAB tool. This simulation is expected to make the learning process become easier in understanding the principal of the system.
Dalam tugas akhir ini diajukan model modulasi orthogonal umum untuk mengidentifikasi sejumlah skema modulasi yang secara luas telah digunakan dan mengoptimasikannya dengan tujuan agar dapat ditemukan lokal optimum sesuai dengan kondisi kanal non-gaussian, yang dimaksud dengan lokal optimum adalah kondisi saat bit error rate terendah. Secara umum, hanya lokal optimum yang benar-benar dapat dipertimbangkan agar masalah optimasi lebih mudah untuk diatasi. Pemodelan sinyal diusulkan berdasarkan vektor orthonormal yang diperoleh dari rotasi multidimensional. Pengoptimasian dilakukan dengan perubahan parameter sederhana pada modulasi. Parameter-parameternya adalah sudut rotasi sederhana dalam ruang multidimensional. Beberapa modulasi yang umum dan secara luas telah digunakan dapat direpresentasikan dengan model ini, contohnya adalah BPSK,QPSK dan OFDM.
Dari simulasi yang dilakukan, perubahan parameter sudut rotasi pada modulasi BPSK, QPSK dan OFDM dari model yang dirancang menghasilkan nilai BER yang berbeda untuk setiap parameternya dan pada sudut tertentu menghasilkan nilai BER terendah atau kondisi lokal optimum. Evaluasi performansi modulasi dari model yang dirancang menunjukkan bahwa modulasi dari model yang dirancang memiliki inerja yang lebih bagus dibanding modulasi dari mapper coding gray.
Kata Kunci : -ABSTRACT: Channel impairment and radio standard differences in telecommunication equipment need different hardware to match with the impairment, of course that will be a wasteful hardware. Those hardware components can be integrated into one hardware system with software support, which is called software radio. The goal of software radio is to enhance the functionality of equipment with software rather than hardware.In software radio, modulation must be changed to detect optimum scheme according to the channel condition. That’s why the change of modulation and modulation scheme optimization becomes important to develop software radio. The widely used modulation schemes have their own name, and classified as different modulation. They usually have a small number of parameters to be optimized.
This final project will propose general orthogonal modulation model to identify some widely used modulation and to optimize it in order to find the local optimum because of non-Gaussian channel impairment. Local optimum is a condition with the lowest bit error rate. In general, only a local optimum can be considered to keep the optimization problem feasible. The model proposed based on orthonormal vectors which are obtained by multidimensional rotation. In this model, a change of parameters corresponds to a change of modulation. The parameters are simply rotation angles in multidimensional spaces. Some widely used modulation can be represented with this model, for example is BPSK, QPSK and OFDM.
Result of the simulation is that the changes of rotation angle parameter on BPSK, QPSK and OFDM modulation of the proposed model have different BER for each parameter and in certain parameter has the lowest BER or local optimum condition. Performance evaluation from the proposed model shows that the modulations from the proposed model have better performance than modulation by coding gray mapper.
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