Electronics and Telecommunications Research Institute

University-industry Cooperation Group of Kyung Hee University

Ajou University Industry-academic Cooperation Foundation

Chang Joo Kim

Jung Sun Um

Sung Hyun Hwang

Myung Sun Song

Byung Jang Jeong

Hoi Yoon Jung

Gwang Zeen Ko

Gwangzeen Ko

Bub Joo Kang

Je Hoon Yun

Sang Won Kim

Young Bae Ko

Byung Chan Kim

Kyung Yul Cheon

Yun Hee Kim

Sung Jin You

Jae Beom Kim

The present invention provides a method and system for performing distributed channel sensing in which channel information is collected by performing channel sensing according to a channel sensing priority which is determined according to a relative position of a cell to which a wireless connection device belongs from among a plurality of cells which logically partition the zone of the wireless network, and thus the overhead of the channel sensing which is generated in a cognitive wireless multi-hop network environment is reduced, and the transmission failure which occurs when the wireless connection device detects frequencies is reduced.

Method and system of distributed sensing for reducing spectrum sensing overhead in cognitive wireless multi-hop networks

A method of assigning a frequency channel using efficient spectrum sensing in a multiple Frequency Assignment system includes a channel sensing process, wherein a base station of a secondary user classifies multiple frequency channels licensed to a primary user into a plurality of channel state sets according to usage states, periodically senses channel states by changing a sensing period according to the types of classified channel state sets, and manages the sensed channel states as frequency channel state set information; a channel state set broadcasting process; and a channel assigning process. Accordingly, a frequency channel can be assigned to a secondary user requesting channel assignment using frequency channel state set information without a primary user experiencing interference noise.

Method of frequency channel assignment using effective spectrum sensing in multiple frequency assignment system

Provided is an apparatus for controlling subcarrier spacing in a system supporting multiple frequency bands. The apparatus for controlling a subcarrier spacing comprises: an interference detection unit detecting interference over multiple frequency bands; a system parameter provision unit providing system parameters related to a subcarrier spacing between the multiple frequency bands&#x2014;for example RF, FFT size, and channel bandwidth; a subcarrier spacing control unit controlling the subcarrier spacing such that the detected interference is reduced, on the basis of the system parameters. In a system operating with multiple bands, different subcarrier spacing can be applied by each band, thereby controlling interference occurring in each band.

Apparatus and method for controlling subcarrier spacing in a wireless communication system

A communication method of a transmitter using a preamble in a wireless communication system, includes determining at least two subcarriers from among a plurality of subcarriers, for the preamble; mapping a subcarrier sequence and a subcarrier phase value of the preamble to the at least two subcarriers; and transmitting the preamble using the at least two subcarriers. The preamble may include a real component having a first repeated pattern in a preset time interval, and an imaginary component having a second repeated pattern in the preset time interval, and a relationship between the first repeated pattern and the second repeated pattern may indicate characteristic information of the wireless communication system.

Communication method using a preamble to share characteristic information, method for generating the preamble, and communication system to which the methods are applied

A wireless communication system provides a method and device for transmitting a preamble. A transmitter generates a first preamble sequence used for frequency offset estimation and generates a second preamble sequence according to the transmission mode. The transmitter transmits the first and second preamble sequences. With respect to the second preamble sequence, the phase thereof may be shifted into different phase offsets according to the transmission mode.

Method and device for transmitting a preamble in a wireless communication system

The present invention relates to a method for reducing an average time period adopted at the time of evaluating an effect of electromagnetic fields of a mobile communication base station near the mobile communication base station on a human body and measurement is performed for 6 minutes at a predetermined measurement point for acquiring a whole body average by comparing a site measurement result targeting multiple base stations and uncertainty by repetitive measurement and when a 6-minute average value and an average value for a reduced time period which is shorter than 6 minutes are compared with each other, a standard deviation is equal to or lower than a predetermined level, e.g., 0.4 dB, it is sufficient even by the measurement for the reduced time period which is shorter than 6 minutes.

Method and device for evaluating influence of electromagnetic waves of base station on human body

The present invention relates to relay customer premises equipment (RCPE) for exchanging operational information and coexistence information of each cell between adjacent cells in a cellular system. The present invention enables effective control between multiple cells by directly transmitting operational information and coexistence information between cells over air links.

Relay station for cell information exchange between adjacent BSs over air links in cellular systems

Provided are a method for using a flexible bandwidth in an orthogonal frequency division multiple access (OFDMA)-based cognitive radio system, and a base station (BS) and a subscriber station using the method. The method includes: allocating a channel band from among unused channel bands having a bandwidth that is a natural number times a bandwidth resolution to customer premises equipment (CPE), wherein the bandwidth resolution is a predetermined bandwidth smaller than a bandwidth of a broadcast channel band, and transmitting an OFDMA-based signal comprising band allocation information indicating information regarding the allocated channel band.

Method for using flexible bandwidth in OFDMA-based cognitive radio system, base station and subscriber station using the same

Provided is a method of assigning a frequency channel using efficient spectrum sensing in a multiple Frequency Assignment (FA) system. The method includes a channel sensing process, wherein a base station (BS) of a secondary user classifies multiple frequency channels licensed to a primary user into a plurality of channel states by changing a sensing period according to the types of classified channel state sets, and manages the sensed channel states as frequency channel state set information; a channel state set broadcasting process, wherein the BS transmits the frequency channel state set information managed in the channel sensing process to secondary user terminals using a broadcast message; and a channel assigning process, wherein if the BS receives a channel assignment request message from a new secondary user terminal which has received the broadcast message, the BS assigns an unused frequency channel from among frequency channels licensed to the primary user to the new secondary user terminal using the frequency channel state set information. Accordingly, a frequency channel can be assigned to a secondary user requesting channel assignment using frequency channel state set information without a primary user experiencing interference noise.

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Daejeon, South Korea

Chang Joo Kim