摘要:
Provided is a large range management device (LRMD) of managing a communication between a plurality of small range devices (SRDs) and a plurality of large range devices (LRDs), the SRDs and the LRDs being located in a single cell and having different transmission coverage, the LRMD including an access slot allocation unit to allocate an SRD access slot to a radio resource for a downlink, to enable a first SRD to request an association from a network, a selection unit to select a communication relay device for relaying relay data of the first SRD, a relay slot allocation unit to allocate at least one SRD relay slot to a radio resource for an uplink, to enable the communication relay device to relay the relay data to a second SRD or another LRD, and a receiving unit to receive the relay data based on the at least one SRD relay slot
摘要:
There is a provided a method for managing a multiple frequency assignment using a terminal's RX performance in an orthogonal frequency division multiple access (OFDMA) wireless regional area network (WRAN) system, including: a) measuring a bit energy/noise power spectral density (Eb/No) and a received signal strength indicator (RSSI) which are received in the terminal; b) informing the measured Eb/No and RSSI of a base station; c) calculating a round trip delay (RTD) in the base station; d) determining a terminal performance level based on the measured Eb/No, RSSI and the calculated RTD; and e) determining a frequency channel and modulation scheme based on the determined performance level.
摘要:
A method and apparatus for allocating subchannels in an orthogonal frequency division multiple access (OFDMA) system is provided. In the method and apparatus, mixed bands in each of which adjacent subcarriers and distributed subcarriers are mixed are used to form a band of a basic physical resource. Accordingly, diversity subchannels each comprised of distributed subcarriers distributed over the whole band and band subchannels each comprised of adjacent subcarriers adjacent to parts of the band are formed in a single OFDMA symbol, thereby simultaneously and flexibly allocating subchannels to users.
摘要:
Provided are a transmission method and apparatus for allocating a subchannel and forming a stationary beam to maximize transmission efficiency in an OFDMA based wireless communication system. The method includes determining the subchannel for the equipment of each user based on the channel state of the equipment of each user, determining a beam index for the equipment of each user, based on location information and direction of arrival information of the equipment of each user, generating an OFDM symbol by mapping a modulation symbol corresponding to the equipment of each user to the determined subchannel, and transmitting the generated OFDM symbol to a wireless space by forming a beam following the determined beam index. Using the method, the equipment of each user can be allocated with an advantageous subchannel, can remove an interference signal at low cost, and can increase total throughput of an OFDMA system downlink.
摘要:
Provided are an apparatus and method for improving an image quality of an image sensor, capable of adaptively removing noise occurring in a de-mosaicking that is performed for generating three-channel data of R, G and B from a single channel pixel structure based on a bayer pattern. The apparatus includes a first converting unit for converting RGB color data into a YCbCr color data, the RGB color data being obtained from bayer data through a de-mosaicking, a noise removal unit for removing noise from a Cb and a Cr color data outputted from the first converting unit, and a second converting unit for converting the Cb and the Cr color data from the noise removal unit and a Y data from the first converting unit into the RGB color data.
摘要:
A data transmitter and receiver for improving a data rate, and more particularly, to an apparatus and method of transmitting and receiving an orthogonal frequency division multiplexing (OFDM) symbol in which a pilot signal is added to a data signal is provided. The apparatus includes a transmitter including: a pilot adder to add a pilot signal to a data signal; and a guard interval inserting unit to insert a guard interval to the data signal with the added pilot signal, and a receiver including: a guard interval removal unit to remove a guard interval in a received time domain signal; a fast Fourier transform (FFT) unit to transform the time domain signal in which the guard interval is removed to a frequency domain signal; a channel estimator to estimate a channel value from the time domain signal in which the guard interval is removed; an equalizer to equalize the frequency domain signal based on the estimated channel value; and a pilot signal removal unit to remove the pilot signal in the equalized frequency domain signal.
摘要:
A resource allocation method for an orthogonal frequency division multiplexing access (OFDMA) system is provided. The resource allocation method includes dividing a frequency band occupied by a predetermined number of OFDM symbols into a plurality of subbands and determining the number of diversity subchannels, each of which comprises at least two time-frequency resources respectively included in different subbands, and the number of subband selective subchannels, which comprise time-frequency resources that are not included in the diversity subchannels; and generating the diversity subchannels and the subband selective subchannels according to the determined numbers and allocating a physical channel comprised of a generated subchannel to a user in a cell. Accordingly, diversity is enhanced without reducing the freedom of selection of a subband.
摘要:
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.
摘要:
A wired/wireless communication receiver includes an equalizer through multipath delay estimation and a signal receiving method. The receiver includes a delay spread estimation unit, a factor updating unit, and an equalizer. The delay spread estimation unit estimates a delay spread value of a received signal and uses a symbol boundary information signal to determine a filtering tap length value and a filtering step size value from an estimated delay spread value. The factor updating unit updates filtering factors using the filtering tap length value and the filtering step size value. The equalizer compensates distortion of the received signal using the filtering factors.
摘要:
Provided is a large range management device (LRMD) of managing a communication between a plurality of small range devices (SRDs) and a plurality of large range devices (LRDs), the SRDs and the LRDs being located in a single cell and having different transmission coverage, the LRMD including an access slot allocation unit to allocate an SRD access slot to a radio resource for a downlink, to enable a first SRD to request an association from a network, a selection unit to select a communication relay device for relaying relay data of the first SRD, a relay slot allocation unit to allocate at least one SRD relay slot to a radio resource for an uplink, to enable the communication relay device to relay the relay data to a second SRD or another LRD, and a receiving unit to receive the relay data based on the at least one SRD relay slot.