Electronics and Telecommunications Research Institute

University-industry Cooperation Group of Kyung Hee University

Myung-Sun Song

Chang-Joo Kim

Sung-Hyun Hwang

Jung-Sun Um

Gwangzeen Ko

Bong-Su Kim

Kwang-Seon Kim

Woo-Jin Byun

Sung-Jin You

Sang-Won Kim

Tae-Jin Chung

Moon-Won Lee

Ki-Chan Eun

Min-Soo Kang

Changhyun Park

Bub-Joo Kang

Minsoo Kang

Chung-Gu Kang

Yun-Hee Kim

Byung-Jang Jeong

Hoi-Yoon Jung

Sunmin Lim

Min-Sheo Choi

Il-Hwan Kim

Hyung-Rae Park

Sung-Jin Yoo

Sun-Min Lim

Gwang-Zeen Ko

Jung-Sun 408-205 Jugong-4Danji Apt 908 Um

Provided is a method of generating a pilot pattern capable of perform adaptive channel estimation, and a method and apparatus of a base station and a method and apparatus of a terminal using the pilot pattern. The pilot pattern selects pilot symbol positions based on distances from pilots of previous orthogonal frequency division multiple access (OFDMA) symbols to a subcarrier position of a current OFDMA symbol in the frequency domain and the time domain, so that a low pilot density is maintained so as to effectively transmit data, and stable channel estimation performance can be obtained even in a bad channel environment. In addition, the minimum burst allocation size is determined according to the channel environment between the base station and the terminal, guaranteeing channel estimation performance suitable for the channel environment, and improving granularity, channel estimation latency, and channel estimation memory size.

Method of generating pilot pattern for adaptive channel estimation in OFDMA systems, method of transmitting/receiving using the pilot pattern and apparatus thereof

A method and an apparatus for controlling transmit power of a CR device are provided. The method includes acquiring CR environment information regarding a licensed user or an unlicensed user occupying an adjacent channel or an adjacent cell of the CR device; determining a transmit power value of the CR device using the CR environment information; and generating transmit power control information including the transmit power value. The method and apparatus guarantee reliable communication of the CR device and minimize interference with the licensed user.

Transmission power control method and device for cognitive radio device

Disclosed herein are an apparatus and a method of estimating a channel in consideration of a residual synchronization offset. The apparatus of estimating a channel in consideration of a residual synchronization offset includes: a channel estimating unit estimating the channel using pilots scattered over a plurality of OFDM symbols and calculating a first channel estimated value as the estimation result, in the case in which an OFDM symbol estimating the channel and an OFDM symbol compensating for the channel are different from each other; and a phase reflecting unit calculating a phase generated by the residual synchronization offset in proportion to a difference between a channel estimation time and a channel compensation time, reflecting the calculated phase in the first channel estimated value, and calculating a second channel estimated value as the reflection result.

Apparatus and method of estimating channel in consideration of residual synchronization offset

Provided is a hybrid beaconing method in which a centralized beaconing scheme and a distributed beaconing scheme are combined. In the hybrid beaconing method, a beaconing scheme is converted according to a network condition, and a centralized beaconing scheme or a distributed beaconing scheme is used to maintain an optimum network status.

Hybrid beaconing method

Provided is a method and apparatus for efficiently transmitting and receiving a frame including a header and a payload in a communication system. If the number of repeated items in the content of a header of the frame is high, specific preambles are allocated to the repeated items and the repeated items are omitted. Accordingly, data transfer efficiency can be improved.

Method and apparatus for compressing frame

Provided are a method of adaptively allocating appropriate hybrid bursts according to terminal attributes including terminal position, channel state, and service type in an orthogonal frequency-division multiple access (OFDMA) system, and an upstream-MAP information element (US-MAP IE) structure supporting the method. The method includes dividing an upstream subframe into a plurality of zones depending on the number of OFDMA symbols and allocating bursts of a zone to a terminal according to the terminal attributes. Bursts are formed by allocating slots along a time axis in the upstream subframe, and are formed by allocating slots along a frequency axis in a downstream subframe.

Method and apparatus of hybrid burst mapping in OFDMA systems

Provided are methods of spectrum sensing and assigning quiet periods in a cognitive radio system in order to increase the reliability of detection regarding whether an incumbent user appears in his/her frequency channel, customer premises equipment (CPE), a base station, and the structure of a super frame for performing the methods. The spectrum sensing method includes communicating with a base station (BS) and performing spectrum sensing for frequency channels having quiet periods (QPs) during the QPs of the frequency channels used in the cognitive radio system, wherein the QPs of the frequency channels do not overlap each other

Method for sensing spectrum and arranging quiet period in cognitive radio system, customer premise equipment, base station and superframe structure using the same

A resource reservation method between a master device and a slave device or between slave devices in a centralized network. In resource reservation between slave devices, optimal resources may be allocated by performing link measurement between the slave devices before allocating the resources.

Reserving resources in centralized network by scanning superframes equal to or greater than maximum number of superframes allowed without listening to beacon period

A channel switching method is provided for a base station to allocate a slot for data exchange with each of a plurality of terminals in a frequency channel that is not used by an incumbent user (IU). The method includes include transmitting a channel switching message for requesting to switch to a backup channel when a signal of the IU is sensed in the frequency channel; transmitting a beacon frame via the backup channel, wherein the beacon frame comprises allocation information about slots which are in the frequency channel and which are respectively allocated to each of the plurality of terminals; and allocating the slot for data exchange with each of the plurality of terminals to the backup channel according to the allocation information, and communicating with each of the plurality of terminals.

Channel switching apparatus and method of a base station and channel switching apparatus and method of a terminal based on the cognitive radio system

Provided are a network communication method and a network device using a preamble. According to the network communication method and the network device, network coexistence is easily achieved by using network identification transmitted in the preamble, and an unknown terminal, which has a low reception signal to noise ratio (SNR) and has not yet been connected to an existing network, is easily connected to the existing network.

Network communication method and network device using preamble

A method for managing a channel set for dynamic channel allocation, and a system for performing the method. The method includes predicting a channel state and a channel quality on a vacant channel based on channel information that is obtained by spectrum sensing and communication protocol. The predicting includes modeling an occupation pattern of the vacant channel to calculate a probability in which an incumbent user (IU) licensed to use the vacant channel appears on the vacant channel. The method also includes evaluating reliability on the prediction result, and giving a priority to the vacant channel based on the evaluated reliability.

Method and system for managing channel set for dynamic channel allocation

A method for detecting a received signal includes: dividing the entire band of the received signal into N frequency components where N is a natural number larger than one, and deciding a reference frequency component containing a reference frequency as a first priority sensing band among the N frequency components; deciding the sensing priorities of the other (N&#x2212;1) frequency components in such a manner that the sensing priorities spread in both directions from the first priority sensing band; calculating the magnitude of each of the N frequency components in accordance with the decided sensing priorities; comparing the calculated magnitude of the frequency component with a predetermined threshold value; and when the calculated magnitude of the frequency component is larger than the threshold value, determining that the received signal exists.

Method and apparatus for detecting received signal in wireless communication system

Provided is a digital predistortion linearizer applicable to millimeter-wave band point-to-point communications. The digital predistortion linearizer includes a transmission unit and a reception unit. The reception unit receives a first signal including a transmission signal and a distortion signal through a millimeter-wave propagation environment, detects the distortion signal from the first signal, and transmits information on the detected distortion signal with the first signal to the transmission unit. The transmission unit generates a predistortion signal using the information on the distortion signal and the first signal received from the reception unit, couples the generated predistortion signal with the transmission signal, and outputs the coupled signal.

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Daejeon, South Korea

Myung-Sun Song