Analisis Efek Near Far Terhadap Interferensi Pada Sistem Komunikasi HF TRDMA

Prady, Amaludin Ibnu (2015) Analisis Efek Near Far Terhadap Interferensi Pada Sistem Komunikasi HF TRDMA. Undergraduate thesis, Institut Technology Sepuluh Nopember.

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Abstract

Sistem komunikasi radio High Frequency (HF) memiliki kelebihan yakni dapat memberikan transmisi jarak jauh, biaya relatif murah serta fleksibel. Namun, karena bandwidth kanal yang digunakan pada sistem komunikasi HF terbatas yaitu pada frekuensi 3-30 MHz, diperlukan suatu metode akses jamak yang mampu meningkatkan efisiensi penggunaan kanal. Salah satunya adalah dengan menggunakan metode Time-Reversal Division Multiple Access (TRDMA) pada komunikasi HF. Salah satu permasalahan yang perlu diatasi dalam mengimplementasikan TRDMA pada komunikasi HF adalah efek nearfar. Efek near-far adalah fenomena saat terdapat dua pemancar (atau lebih) yang memancarkan sinyal ke satu penerima yang sama, dalam konteks uplink pada proses multiple-access, yang bekerja dengan frekuensi yang sama. Karena bekerja di frekuensi yang sama, tentu akan ada efek interferensi antara keduanya, sehingga mempengaruhi kualitas sinyal pemancar utama, yang diukur menggunakan parameter signal to interference ratio (SIR). Pengaruh jarak setiap pemancar terhadap kualitas sinyal dari masing-masing pemancar tersebut itulah yang disebut sebagai efek near-far. Pada penelitian ini digunakan data dari rekomendasi ITU-R P.533 untuk mendapatkan kinerja komunikasi pada band HF. Dilakukan mekanisme kontrol daya pancar untuk mendapat hasil SIR ideal untuk semua user, dengan cara menyamakan daya di penerima untuk setiap pemancar, mendekati -120 dBW. Lalu dilakukan perhitungan SIR untuk pemancar utama Kupang dan Merauke, dengan penerima di Surabaya. Didapatkan hasil kinerja SIR komunikasi HF TRDMA, cukup baik hanya jika hanya ada 1 peng-interferensi. Sedangkan lebih dari itu nilainya sudah dibawah 0 dB, sehingga perlu digabungkan dengan teknik spread spectrum, dengan level yang rendah, agar tidak boros dalam penggunaan bandwidth. ========================================================================================================= High frequency (HF) radio communication systems has an advantage, that it can provide a long distances transmission, relatively cheap, and flexible. But consider that the channel bandwidth of HF frequency band was limited, from 3-30 MHz, it is necessary to use an multiple access method to increase channel usage efficiency. Once of it was by apllied Time Reversal Division Multiple Access (TRDMA) method for HF communication systems. One of the problem to be solved to implements TRDMA on HF communications system is near far effect. Near far effect is a phenomenon when there was two transmitter (or more) that propagates a signal to a same receiver, in an uplink context of a multiple access process, using a same frequency. Because of using a same frequency, there was an interference effect between them, that affect to signal quality of the main trasmitter, which caltulated by signal to interference ratio (SIR) parameter. The affection of distances and signal quality of each transmitter is named near far effect. In this research, is using data from ITU-R P.533 to get information about communication performance at high frequency band. We applied transmission power control to get an ideal SIR performance for each user, by equate received power for each user, approach -120 dBW for each user. Then SIR performance was calculated, with the receiver in Surabaya, and two main transmitter at Kupang and Merauke. So we get SIR performance of HF communication systems. It found that SIR performance of HF TRDMA communication systems is only have positive value in dB scale, when only has 1 interference link. When the interference link was 2 or more, the value was negative. So it need to be combined with other techniques such as spread spectrum with a low sequence level, that enough to increase SIR performance, but still efficient in using bandwidth.

Item Type: Thesis (Undergraduate)
Additional Information: RSE 621.384 151 Pra a
Uncontrolled Keywords: Komunikasi HF, TRDMA, Efek Near-Far, SIR
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK5103.2 Wireless communication systems. Two way wireless communication
Divisions: Faculty of Electrical Technology > Electrical Engineering > 20201-(S1) Undergraduate Thesis
Depositing User: Mr. Tondo Indra Nyata
Date Deposited: 14 Feb 2019 07:22
Last Modified: 14 Feb 2019 07:22
URI: https://repository.its.ac.id/id/eprint/62218

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