Showing papers by "Youn-Ok Park published in 2016"
22 May 2016
TL;DR: In this paper, a 2.59GHz self-interference cancellation (SIC) circuit is presented for in-band full-duplex radio, which is based on an analog vector modulator whose output can automatically track the time-varying selfinterference signal through an analog LMS algorithm based weight calculation circuit.
Abstract: A 2.59GHz self-interference cancellation (SIC) circuit is presented for in-band full-duplex radio. The SIC circuit is based on an analog vector modulator whose output can automatically track the time-varying self-interference signal through an analog LMS algorithm based weight calculation circuit. By adding a variable gain stage after the vector modulator, the total dynamic range is significantly widened so that the SIC can deal with large Tx power variation and/or Tx-to-Rx attenuation. Implemented in 16.4 × 11.9 cm2 printed circuit board, the circuit achieves the cancellation ratio of 39.2 dB and 39.4 dB for 5MHz and 10MHz bandwidth 16-QAM signal, respectively. Also, the dynamic range is increased from 22 dB to 40 dB by properly setting the variable gain.
11 citations
TL;DR: It is shown that about 3dB Eb/N0 gain is obtained at the BER of 10-4 and the CPR of 10dB by the polarization-domain rotation scheme with optimal rotation angles compared with the conventional orthogonal dual-polarization transmission.
Abstract: We consider the problem of bit error rate BER degradation because of the power gain imbalance between horizontal H-polarization and vertical V-polarization components in an orthogonal dual-polarization transmission system. To alleviate the aforementioned BER degradation problem, we propose a non-orthogonal polarization-domain rotation scheme where the axes of H-polarization and V-polarization components are rotated with different angles at the transmitter and de-rotated at the receiver. In addition, in order to assess the effectiveness of the polarization-domain rotation scheme, we derive the closed-form BER expression under a practical dual-polarized channel model, which is represented by cross-polarization ratio and co-polarization ratio CPR. We also derive the approximated BER expressions for the two asymptotic values of CPR: balanced CPR and infinite CPR. With the derived BER expressions, we find the optimal rotation angles that jointly minimize the BER. According to the numerical results, it is shown that about 3dB Eb/N0 gain is obtained at the BER of 10-4 and the CPR of 10dB by the polarization-domain rotation scheme with optimal rotation angles compared with the conventional orthogonal dual-polarization transmission. Copyright © 2015 John Wiley & Sons, Ltd.
3 citations
01 Jan 2016
TL;DR: This paper proposes to utilize carrier aggregation (CA) from additional base stations for relieving the uneven beamforming zone area problem and proves this method is more efficient in improving cell throughput especially in mmWave environment.
Abstract: The 3-dimensional beamforming is a highly attractive issue in 5G telecommunication. Equipped with 2-dimensional antenna arrays, it allows vertical sectorization within a cell as well as horizontal one, by making a beamforming zone for the corresponding sector. However, there is considerable inequality among the areas of beamforming zone. Since the farther from the base station, the bigger the beamforming zone area is, the farther beamforming zone area is likely support more users than nearer beamforming zone. In this paper, we propose to utilize carrier aggregation (CA) from additional base stations for relieving the uneven beamforming zone area problem and prove this method is more efficient in improving cell throughput especially in mmWave environment. Even if the additional base station is more simple type which offers only a few beamformings, it can effectively improve the equality of UE's radio resource occupation.
TL;DR: The physical layer modem structure of Giga KOREA 5G system is described, which is composed of high performance baseband station as well as mobile station and their OFDM TDD modems.
Abstract: This paper describes the physical layer modem structure of Giga KOREA 5G system which is being developed by ETRI as a 5G telecommunications prototype. The objective of Giga KOREA 5G system is supporting maximum 100 Gbps data rate for each cell with wide-bandwidth baseband station and mobile station prototypes in mmWave (10~40 GHz) environment. To achieve this objective, its physical layer is composed of high performance baseband station as well as mobile station and their OFDM TDD modems. The important features of Giga KOREA 5G physical layer are carrier aggregation, multiple receiving beam searching in mobile station, high data rate channel encoder and decoder and high speed modulation and demodulation functions.