Abstract:
A cell search method for an OFDM(Orthogonal Frequency Division Multiplexing) based FDD(Frequency Division Duplex) and TDD(Time Division Duplex) dual mode mobile station and base station transmission scheme is provided to realize a cell searcher for simply operating both an FDD mode and a TDD mode. A method for transmitting a forward synchronization signal includes the steps of: generating a frame including a plurality of sync blocks; and transmitting the frame through a forward link, wherein the frame includes a first SCH(Synchronization Channel) sequence and a plurality of second SCH sequence and specifies a cell identifier by the first SCH sequence and the plurality of second SCH sequence. The first SCH sequence supplies sync block timing information and the plurality of second SCH sequences supply frame timing information. Both the first SCH sequence and the second SCH sequences are used in TDD and FDD systems.
Abstract:
Downlink resource allocation for an OFDMA system is provided to transmit allocation information about resources to be used in an MS(Mobile Station) when a BS(Base Station) transmits downlink scheduling information to the MS, thereby maximizing the amount of resources used in data transmission and increasing a data transmission rate. A method for transmitting resource allocation information comprises the following steps of: constructing continuous physical resources as a sub band; constructing the sub band allocation information as a binary bitmap to transmit the constructed binary bitmap to a first control channel; and constructing allocation information within the sub band regarding the sub band as a binary bitmap to transmit the constructed binary bitmap to a second control channel.
Abstract:
An uplink signal transmission method of a communication system, a transmission device, a generation method, and a generation device are provided to randomize interference between users and cells when a frequency domain CDM(Code Division Multiplexing) method is used, thereby reducing the interference between users. At the first transmission time, the first sequence for distinguishing a terminal from another terminal is multiplied by the first transmission symbol to transmit the multiplied sequence. At the second transmission time different from the first transmission time, the second sequence for distinguishing the terminal from another terminal is multiplied by the second transmission symbol to transmit the multiplied sequence. The second sequence is different from the first sequence.
Abstract:
A data transmission method of an MS(Mobile Station) using a cell search signal and a device thereof are provided to enable the MS to determine a location by itself by using cell search signals received from base stations within a home cell and neighboring cells, and to estimate uplink delay time information, thereby omitting RACH(Random Access Channel) burst transmission. An MS receives cell search signals from base stations within a synchronized home cell and base stations within at least more than neighboring cell(S710). The MS calculates receiving time differences between the cell search signals received from the base stations within the home cell and the neighboring cells(S720). The MS calculates uplink delay time of the neighboring cells based on the receiving time differences(S730).
Abstract:
A cell search method in an OFDM(Orthogonal Frequency Division Multiplexing) cellular system, a frame transmission method therefor, and a forward link frame structure are provided to smoothly perform handover by effectively searching an adjacent cell, and reduce the amount of battery consumption of a mobile station. The first detecting unit obtains symbol synchronization by applying a matching filter to a reception signal(S800). A hop pattern correlation values are calculated by using reception synchronous channel symbols extracted from the reception signal based on the obtained symbol synchronization information, and a hop pattern of a target cell is detected based on the calculated hop pattern correlation values(S820). A code group and a frame boundary of the target cell are detected based on the detected hop pattern(S840). Pilot correlation values of common pilot channel symbols and scrambling codes belonging to the detected code group are calculated, and the scrambling codes of the target cell are detected based on the calculated pilot correlation value(S860). It is checked whether the detection results are reliable(S880).
Abstract:
A transmission method for obtaining random access diversity in a mobile station is provided to increase the RACH(Random Access CHannel) signature detection probability of a base station by applying a TSTD(Time Switching Transmit Diversity) technique, a frequency hopping technique, and a power ramping technique to RACH burst transmission in various combinations. A transmitting apparatus having two Tx antennas(140,150) in a mobile station comprises an OFDMA(Orthogonal Frequency Division Multiple Access) modulating unit(110), a transmitting unit(120), and a power controlling unit(130). The OFDMA modulating unit(110) allocates an RACH burst(S1) to a specific subband, executes OFDMA modulation, and makes an RACH burst signal(S2). If an ACK signal for the RACH burst is received from a base station, the OFDMA modulating unit(110) modulates user packet data containing an RACH message and transmits the modulated data to the transmitting unit(120). The transmitting unit(120) transmits the RACH burst signal(S2), outputted from the OFDMA modulating unit(110), to the base station using the Tx antennas(140,150) alternately. If the ACK signal for the RACH burst is received, the transmitting unit(120) amplifies and upconverts the OFDMA-modulated user packet data and transmits the data through a Tx antenna which receives the ACK signal. The power controlling unit(130) creates a control signal(S4) to control the power of the RACH burst signal(S2).
Abstract:
A method for transmitting signals in a base station and a method for transmitting feedback information in a mobile terminal are provided to decrease the amount of feedback information, transmitted to a base station from a mobile terminal, by previously allocating some precoding matrixes or Tx antennas to each frequency group. A base station segments an allocated frequency band into a plurality of frequency groups. The base station allocates one or more precoding matrixes among a plurality of precoding matrixes to each of the divided frequency groups. The base station receives feedback information from a mobile terminal. The base station transmits signals using the frequency of a frequency group corresponding to the received feedback information and the precoding matrixes allocated to the corresponding frequency group.
Abstract:
A method for creating a downlink signal and a method for cell searching are provided to enable a mobile station to execute fast synchronization acquisition and cell searching by dividing a frame into a plurality of synchronization blocks and arranging a frame synchronization identification sequence for each synchronization blocks. A downlink frame creation part creates a downlink frame containing a plurality of synchronization blocks, and arranges an identical cell ID code group at the synchronization intervals(S110). An IFFT(Inverse Fast Fourier Transform) computation part executes IFFT by using the downlink frame and creates a time domain signal(S120). A frame synchronization application part applies a frame synchronization identification sequence to each synchronization blocks and creates a downlink signal(S130). A transmitting part converts the created downlink signal into an analog signal, executes modulation and demodulation, and transmits the result through an antenna(S140).
Abstract:
An apparatus and a method for generating a downlink signal, and an apparatus and a method for searching a cell are provided to perform a rapid synchronization acquisition and a cell search by dividing one frame into a plurality of synchronization blocks and arranging a different synchronization identifying sequence in each synchronization block. A method for generating a downlink signal includes the steps of: generating a downlink frame(S110); arranging a cell group identifying sequence corresponding to a predetermined cell in a synchronization section of the downlink frame so that a plurality of repeated patterns are formed in a time domain(S130); transforming the downlink frame into a time domain signal; and multiplying a plurality of orthogonal identifying codes which form a frame synchronization identifying sequence in a time domain signal by the plurality of repeated patterns, and generating the downlink signal.
Abstract:
An apparatus for generating a down link signal, and a method and an apparatus for restoring data in a cellular system are provided to improve calculation efficiency of LLR(Log-Likelihood Ratio) for a soft decision by calculating interference fading and noise. A method for restoring data in a cellular system includes the steps of: performing equalization for compensating delivering time delay deviation and reduction for each frequency included in a received signal(S110); detecting interference element caused by fading inside a cell, and channel coefficients including fading element generated by neighboring cells(S120); detecting a dispersion of an AWGN(Additive White Gaussian Noise) element included in the received signal(S130); calculating the dispersion of entire noise element which the fading element and AWGN is considered(S140); calculating an LLR for a corresponding received signals(S150); and deciding the received signal by performing a soft decision by using the LLR.