Enhanced MMSE FDE to Mitigate Multiuser Interference in MC-CDMA System

Carrier Frequency Offset (CFO) occurs due to asynchrony between transmitter and receiver local oscillator, and/or due to Doppler Effect that is caused by high mobility. Due to CFO, the orthogonality between subcarriers can be disrupted. In the uplink system, different carrier frequency offsets of different users at the receiver resulting multiuser interference (MUI), thus degrade the performance of MC-CDMA system. In the previous study, Modified Minimum Mean Square Error Frequency Domain Equalization (Modified MMSE FDE) has been proposed by Agnihotri which results in a better performance than the conventional MMSE. However, the achieved Bit Error Rate (BER) is not smaller than 10-2 for Signal to Noise Ratio (SNR) below 20. This research design a new algorithm in Multi-carrier Code Division Multiple Access (MC-CDMA) receiver side to mitigate MUI, that is called Enhanced MMSE FDE. Enhanced MMSE FDE is a modification of Modified MMSE-FDE to improve the system performance. Enhanced MMSE FDE takes into account the rest of MUI as well as Modified MMSE FDE to design FDE coefficient, but Enhanced MMSE FDE use CFO estimation that is not on Modified MMSE FDE. The value of CFO is estimated and regenerated in the receiver and then used to estimate MUI. MUI is assumed to be reconstructed and eliminated from the received signal. In order to get signal processing more efficient, Enhanced MMSE FDE takes only the real trace of FDE matrix. The simulation result shows that MC-CDMA with Enhanced MMSE FDE using Binary Phase Shift Keying (BPSK) and 64 subcarriers with 4 users gives better performance than MC-CDMA with Conventional MMSE and Modified MMSE FDE that have been performed by Agnihotri. However, the complexity of Enhanced MMSE FDE that takes the whole of FDE coefficient matrix is higher than Modified MMSE FDE. By taking only the real trace of FDE coefficient matrix, complexity of Enhanced MMSE FDE is getting simpler than taking the whole of FDE coefficient matrix. Furthermore, Enhanced MMSE FDE that takes only the real trace of FDE coefficient matrix is 2.93 % more efficient than Enhanced MMSE FDE that takes the whole of FDE coefficient matrix. Keyword-multiuser interference, Enhanced MMSE FDE, MC-CDMA

Perancangan Sistem Notifikasi Serta Kendali Suhu dan Kelembapan Menggunakan Aplikasi BLYNK Untuk Budidaya Jamur Tiram

Urban farming (gardening in the middle of the city) is increasingly in demand by modern society. Urban farming provides business opportunities as well as being a lifestyle trend. One of the plants that can be cultivated at home is oyster mushroom. Oyster mushroom cultivation is quite easy but requires a special environment to grow up. To do mushroom cultivation at home, it is necessary to manage temperature and humidity to achieve optimal temperature and humidity. A temperature and humidity control system that can be monitored and controlled through the smartphoneis the result of the study. Temperature and humidity detected by the DHT22 sensor, then read by NodeMCU and sent to the Blynk application via a WiFi connection are considered as the input system. WiFi used by NodeMCU is the same as WiFi used by smartphones. Blynk on a smartphone will display the temperature and humidity read by NodeMCU. If the temperature and humidity are out of the optimal temperature and humidity range for oyster mushrooms, a notification will appear on the smartphone. Temperature and humidity control can be done by pressing the ON / OFF button on Blynk to turn on and turn off the lights or the fan as needed, so that the temperature and humidity return to optimal. Based on testing, the system successfully displays temperature and humidity on a smartphone, displays notifications and makes control. The relative error of the temperature measurement is 2.6% and the relative error of the humidity measurement is 3.2%

ANALISIS EFFISIENSI PENGGUNAAN BAHAN BAKAR GAS “COMPRESSED NATURAL GAS” (CNG) DAN PERHITUNGAN PORTABLE (MOBILE REFUELING UNIT) UNTUK SEKTOR ANGKUTAN KOTA DI PONDOK LABU JAKARTA SELATAN

Bahan Bakar Minyak masih menjadi sumber energi utama di Indonesia hingga saat ini, baik untuk kendaraan bermotor maupun untuk bahan bakar industri, seiring dengan meningkatnya kebutuhan dan pertumbuhan industri otomotif di Jakarta. Bahan bakar gas jenis compressed natural gas (CNG) memiliki beberapa keuntungan diantaranya harga lebih murah, perawatan mesin lebih mudah dan ramah lingkungan dan dapat menjadi bahan bakar alternatif untuk kendaraan angkutan umum. Sejauh ini, kendala utamanya adalah ketersediaan infrastruktur stasiun pengisian bahan bakar gas (SPBG) yang belum banyak tersedia khususnya di araea Pondok Labu Jakarta Selatan. Untuk mengatasi hal tersebut maka diperlukan suatu penelitan dengan judul “Analisis Effisiensi Bahan Bakar Gas Compressed Natural Gas Dan Perhitungan Portable (Mobile Refueling Unit)”. Penelitian ini memiliki beberapa tujuan yakni : 1). Analisis kebutuhan bahan bakar gas untuk angkuatan kota (Angkot). 2). Mengetahui efisiensi dan kebutuhan MRU. Metode pelaksanaan meliputi penghitungan operasional angkutan kota masing-masing trayek dalam 15 jam perhari, kemudian dilakukan penghitungan jarak tempuh dan kebutuhan BBM per hari. Dengan menggunakan rumus dan penggunaan data pengamatan akan didapat jarak tempuh BBM dan jarak tempuh BBG, yang kemudian untuk menentukan efisiensi biaya hasil konversi BBM ke BBG. Untuk menetukan jumlah Mobile Refueling Unit (MRU) digunakan hasil perhitungan konsumsi BBG lalu dibagi dengan volume MRU. Dari hasil perhitungan menunjukkan bahwa konsumsi BBM sebesar 19067.92 liter per hari, jarak tempuh seluruh trayek sebesar 13.153 km, jarak tempuh BBM 3.060,11 dan jarak tempuh BBG sebesar 3.434,157. Effisiensi rata-rata untuk semua trayek sebesar 56,38125% serta jumlah MRU 10 unit perhari. Total kebutuhan CNG per tahun sebesar 258,07159 MMSCF