GMSK modulator implementation for Earth Explorations Satellite Service (EESS) application: article / Rasidi Nordin @ Radin

• Main Author: Nordin @ Radin, Rasidi
• Format: Article
• Language: English
• Published: 2013
• Subjects: Data transmission systems
• Online Access: https://ir.uitm.edu.my/id/eprint/107836/1/107836.pdf; https://ir.uitm.edu.my/id/eprint/107836/

Due to restriction of the spectrum for Earth Exploration Satellite Service (EESS) at 8.5 GHz X-Band allocation, the mission for EESS are looking higher order modulation scheme instead of traditionally phase shift keying (PSK)such as QPSK, OQPSK and 8-PSK. The main problems with the current modulation are the Bandwidth efficiency and the Inter-symbol Interference Tolerance. The objectives of this paper are to analyze GMSK perform in EESS, to identify the best BT value, to analyze the filtering effect to BW in GMSK, to simulate GMSK in satellite communication using matlab and to compare the performance of GMSK with the OQPSK filtering with square root raised cosine (RRC) in satellite communication. The methodology used in this paper is identify the current OQPSK method used, designed and simulate the GMSK modulation by using the same method used in OQPSK in Matlab and finally compare the simulation result of GMSK with the OQPSK filtered with RRC. The result shows that the GMSK performace is almost same as OQPSK in term of bit error rate (BER). However, the GMSK performance in terms of bandwith efficiency is better compare to the OQPSK. Inconclusions, the GMSK could be used at lower data rates with a performance almost similar to the OQPSK filtered with OQPSK.