Research Information System
4th International Scientific Conference on Advances in Wireless and Optical Communications (RTUWO), Riga, Latvia, 15 - 16 November 2018, pp.6-11, (Full Text)
This paper investigates the relay effects on bandwidth efficiency. The investigation considers that the relay terminals are serially placed between the transmitter and the receiver terminals. The investigation considers that the transmitter terminal possesses the channel state information and also considers log-normal fading channel for the performance analysis. Based on the channel conditions, the transmitter adjusts the modulation sizes in each slot by using the channel state information. During the adaptive transmission, the peak power constraint is addressed to provide eye safety. Results show that the proposed adaptive modulation system significantly enhances bandwidth efficiency in comparison to the non-adaptive system.