Showing papers by "Ji-Yun Seol published in 2016"

Introduction to QAM-FBMC: From Waveform Optimization to System Design

Abstract: The asynchronous heterogeneous network scenario is becoming one of the key features for 5G mobile communications. Compared to CP-OFDM, which is 4G waveform, superior spectrum confinement as well as higher spectral efficiency has been taken into consideration for 5G waveform design. In this article, we introduce a new waveform called QAM-FBMC that provides superior spectrum confinement and higher spectral efficiency simultaneously against CP-OFDM. The article explains fundamental trade-offs in waveform design and shows how they can be optimized for QAM-FBMC. We also introduce the transmission and reception procedures for QAM-FBMC including its similarities and differences compared to well-known waveforms such as CP-OFDM and OQAM-FBMC. Performance evaluation results show where the spectral efficiency gain of QAM-FBMC over CP-OFDM comes from.

Apparatus and method for transmitting reference signals in wireless communication system

Abstract: The present disclosure relates to a 5 th generation (5G) or pre-5G communication system for supporting a higher data transmission rate beyond the 4 th generation (4G) communication system such as long term evolution (LTE) The present invention relates to transmission of a reference signal in a wireless communication system, and an operation method of a terminal comprises the steps of: receiving control information for reference signals from a base station; and receiving the reference signals according to the control information Further, the present invention also comprises embodiments different from the embodiment described above

Apparatus and method for operating full-duplex scheme in communication system supporting beam-forming scheme

Abstract: The present invention relates to a 5th-generation (5G) or a pre-5G communication system provided for supporting higher data transmission rates than 4th-generation (4G) communication systems such as long term evolution (LTE). The present invention relates to a method in which an access point (AP) operates a full-duplex scheme in a communication system supporting a beam-forming scheme, the method comprising the steps of: generating a magnetic interference intensity table according to transmitted beam patterns and received beam patterns; determining, by the AP, a transmitted beam pattern and a received beam pattern for all stations (STAs) on the basis of channel measurement feedback information received from the stations, which provide service, and the electromagnetic-interference intensity table; and performing a communication operation with each of the stations on the basis of the determined transmitted beam pattern and received beam pattern.

Apparatus and method for cancelling self-interference signal in communication system supporting full-duplex scheme

Abstract: The present invention relates to a fifth generation (5G) or pre-5G communication system to support a data rate higher than that of a beyond-fourth generation (4G) communication system such as long-term evolution (LTE). The present invention relates to a method to cancel a self-interference signal in a communication system supporting a full duplex scheme, comprising: a step of estimating a self-interference channel; a step of performing pre-filtering operation with respect to a transmitted signal based on the estimated self-interference channel; a step of generating copied self-interference signals based on the estimated self-interference channel; and a step of cancelling self-interference signals based on the copied self-interference signals, wherein the pre-filtering operation includes operation of reducing the number of self-interference signals from a first number to a second number.

Advanced Quantizer Designs for FD-MIMO Systems Using Uniform Planar Arrays

Abstract: Uniform planar antenna (UPA) structures are expected to become popular for massive multiple-input multiple- output (MIMO) systems because they enable deployment of a large number of antennas in limited space. In frequency division duplexing (FDD) systems, quantized channel state information (CSI) should be fed back from users to base stations to make adaptive transmission possible. However, it is difficult to accurately quantize massive MIMO channels due to their large dimensions. In this paper, we propose practical CSI quantizers for full-dimension (FD) MIMO systems employing UPAs. We focus on quantizing and combining dominant beams in channels by keeping realistic channel properties and antenna structures into account. To scan a channel space, we also develop a multi-round beam search approach. Numerical results verify that the proposed quantizers show better quantization performance than the previous channel quantization techniques.

Method and apparatus for adjusting beam width in wireless communication system

Abstract: The method includes: receiving information on a battery threshold of a terminal from a base station; determining whether to use a reception beam width wider than a currently used reception beam width, by comparing a battery level of the terminal with the battery threshold; transmitting additional resource request information to the base station when it is determined that a wider reception beam width is used; and when an additional resource corresponding to the additional resource request information is allocated from the base station, blocking a power supply of at least one antenna reception circuit among multiple antenna reception circuits corresponding to multiple antenna elements in order to form at least one reception beam having the wide reception beam width

Method and apparatus for repeated transmission in multicarrier wireless communication system

Abstract: A method for signal transmission includes determining whether to perform repeated transmissions for a time length of a multiplication of L and M or more, wherein L indicates the overlapping factor of the system and M indicates a number of quadrature amplitude modulation (QAM) filter bank multi-carrier (FBMC) symbols, determining information on a type of the repeated transmissions to be performed, and transmitting FBMC symbols using a transmit power determined based on the type of the repeated transmissions. A base station includes a transceiver unit to send and receive signals, a control unit configured to determine whether to perform repeated transmissions for a time length of a multiplication of L and M or more, determine information on a type of the repeated transmissions to be performed, and transmit FBMC symbols using a transmit power determined based on the type of the repeated transmissions.

Device and method for transmitting/receiving reference signal in communication system supporting full-dimension multiple input multiple output mode

Abstract: The present invention relates to a 5th-generation (5G) or pre-5G communication system to be provided for supporting a data transmission rate higher than that of a 4th-generation (4G) communication system, such as long term evolution (LTE), and subsequent systems. According to the present invention, a method by which a transmission device transmits a reference signal in a communication system supporting a full-dimension multiple input multiple output (FD-MIMO) mode comprises the steps of: transmitting, to a reception device, reference signals through m number of antenna ports; and transmitting, to the reception device, reference signals through n number of antenna ports, wherein the m number of antenna ports have a first polarization characteristic, the n number of antenna ports have a second polarization characteristic, the m number of antenna ports are included in a first axis of a two-dimensional space to be generated on the basis of a vertical axis and a horizontal axis of a uniform planar array (UPA) antenna, and the n number of antenna ports are included in a second axis of the two-dimensional space.

Apparatus and method for performing beamforming operation in communication system supporting frequency division-multiple input multiple output scheme

Abstract: A pre-5th-generation (5G) or 5G communication system for supporting higher data rates beyond 4th-generation (4G) communication system, such as a long term evolution (LTE), is provided. A method for performing a beamforming operation in a communication system supporting a frequency division-multiple input multiple output (FD-MIMO) scheme is provided. The method includes detecting a rough beam of a first dominant beam, detecting at least two codeword candidates based on the rough beam of the first dominant beam, and selecting one of the at least two codeword candidates as a final codeword.

Method and apparatus for transmitting signal using space time block code or space frequency block code in multi-carrier system

Abstract: An STBC/SFBC-based signal transmission method and apparatus is provided for use in a multi-carrier system A method for a transmitter to transmit a signal to a receiver in a diversity transmission mode according to the present invention includes transmitting a filter index indicating a filter allocated to the receiver and transmitting Space Time Block Code (STBC) symbols to the receiver at symbol positions selected based on the filter index

Transparent operation of Kronecker product based full dimension MIMO to exploit 2D antenna array

Abstract: A concept of full-dimension MIMO (FD-MIMO) adopting 2-dimensional (2D) antenna array has been proposed with intent to cope with practical challenges of massive MIMO systems. In this paper, we investigate an FD-MIMO operation that can be transparently applied with current 3GPP LTE specifications, and propose a novel method that facilitates an accurate estimation of channel quality indicator (CQI) at base station (BS). We first introduce a feedback scheme in which horizontal and vertical dimension channel information are separately reported. To further improve accuracy of modulation and coding scheme (MCS) selection to maximize system throughput, we propose an enhanced feedback scheme that is helpful to more accurate CQI estimation at the BS. In the evaluation results, we show performance improvement of the proposed scheme over the conventional MIMO scheme.