• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.4
• /
• pp.481-488
• /
• 2011

In this paper, we study a novel wireless interference cancellation system(ICS) repeater based on OFDM system with phase noise analysis and performance evaluation. Recently, there were many researches about wireless repeater. The previous study is just considering the feedback channel cancellation algorithm. But, in wireless repeater system, the phase noise effect can exist at up and down converter of wireless repeater. In wireless repeater system, if there are phase noise effects, the performance of system will get worse. So, the phase noise compensator is needed in wireless repeater. Therefore, we propose adaptive phase noise compensator based on OFDM system in order to effectively cancel phase noise. In order to cancel interference, we adapt adaptive phase noise compensator in wireless repeater system. The adaptive phase noise compensator compensates phase noise effect. Therefore, in this paper, we analyze phase noise of wireless repeater based on OFDM system. In this paper, when phase noise power is -15 dBc and phase noise cutoff frequency is 100 kHz at 4QAM, the BER performance of propose algorithm is better about 4 dB than with adaptive equalizer and without phase noise compensator at $10^{-4}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.6
• /
• pp.661-668
• /
• 2012

In this paper, a dual-fed small ICS repeater antenna with high isolation is designed, fabricated, and measured. Bandwidth and gain are optimized by changing the stub lengths near main patch and power divider, and also by changing the size of parasitic patch. To improve the isolation characteristic of the antenna, a dual-feeding method is applied in designing the antenna. The fabricated antenna has a VSWR less than 2, a gain over 7 dBi, and an isolation between the donor and the server antennas less than -65 dB from 1,920~2,170 MHz for 3G mobile communication.

• Journal of the Institute of Convergence Signal Processing
• /
• v.14 no.2
• /
• pp.110-116
• /
• 2013

The amplification rate of a RF repeater is limited by the feedbacked signals from the same repeater. And an ICS (Interference Cancellation System) repeater has been developed to remove the feedbacked signals. The ICS repeater estimates the amplitudes and the phases of the feedbacked signals and removes the estimated feedback signals from the received input signal of the repeater. However, it requires lots of hardware complexity and this leads to the increase the cost of the repeater. Moreover, the ICS repeater can not solve the pilot pollution problems. To solve these problems, we have studied the implementation and adaptation of smart antenna system for RF repeaters. We have designed a smart antenna system with a switching beam structure in order to reduce the hardware and computational complexity. After analyzing the proposed smart antenna system, we found out that the amplification rate of the proposed repeater increases 23dB compare to the amplification rate of ICS repeater and the output SINR increases 6dB compare to the ICS repeater.