Abstract: A method and apparatus for transmitting/receiving a Random Access Channel (RACH) signal in a communication system. A User Equipment (UE) selects one of Contention Resolution (CR) channels allocated for collision detection, and transmits the selected CR channel and a connection request message to an Evolved Node B (E-NB), and receives a response signal from the E-NB. The UE transmits the RACH signal, if a collision indicator is included in the response signal. The E-NB receives from each of UEs a connection request message and a CR channel, decodes the connection request message, and detects a collision between the UEs using the CR channel. The E-NB generates a response signal to the connection request message according to the decoding result, generates a collision indicator according to the collision detection result, and transmits to the UEs at least one of the generated response signal, the generated collision indicator, and a unique ID of a corresponding UE.

Abstract: A method for allocating frequency resources to be used for multiple terminals in a Frequency Division Multiplexing (FDM) wireless communication system in which a base station communicates with the multiple terminals in a predetermined service frequency band.

Abstract: Disclosed is a method for allocating resources in a base station of a wireless communication system that performs communication using frequency resources. The method includes dividing subcarriers into subcarrier sets each including a predetermined number of consecutive subcarriers, and generating a resource index table mapped to consecutive indexes such that a distance between subcarriers in the subcarrier sets is maximized; and determining an amount of resources to be transmitted through a downlink according to a channel condition, for data to be transmitted to each terminal, and allocating resources to the terminal using the index value in the resource index table.

Abstract: Provided is a method and an apparatus for transmitting uplink information items having various characteristics by using a single FFT block. The method includes determining if there is uplink signaling information to be transmitted when there is uplink data to be transmitted; time multiplexing the uplink data and a first pilot for the uplink data and transmitting the multiplexed uplink data and first pilot, when there is no uplink signaling information; and time multiplexing the uplink data, the first pilot for the uplink data, and a second pilot for the uplink data and the uplink signaling information, and transmitting the multiplexed uplink data, first pilot, and second pilot, when there is the uplink signaling information.

Abstract: A method and apparatus for allocating resources and signaling the allocated resources in an FDMA communication system where different frequency resources are allocated to different UEs for data transmission are provided, in which at least one of subbands mapped to subcarrier sets in a frequency domain is allocated to a UE, the subband index of each of the subbands being a BRO representation of the binary value of an offset indicating the position of a first subcarrier in a subcarrier set corresponding to the each subband, resource allocation information indicating the allocated at least one subband is sent to the UE, and one of data transmission and reception to and from the UE is performed in at least one subcarrier set corresponding to the at least one subband indicated by the resource allocation information.

Abstract: A method and apparatus for controlling transmission and reception of dedicated pilots according to an MCS level in a wireless communication system are provided, in which an MCS level is determined for a data channel, the amount of resources for sending dedicated pilots is determined in inverse proportion to the MCS level, a pilot channel signal including basic pilots mapped to resources allocated to a pilot channel, a control channel signal including control information mapped to resources allocated to a control channel, and a data channel signal including the dedicated pilots mapped to the determined amount of resources being part of resources allocated to the data channel and data mapped to the remaining of the resources allocated to the data channel are generated, and the pilot channel signal, the control channel signal, and the data channel signal are multiplexed and sent in the mapped resources.

Abstract: A transmission/reception apparatus and method are provided for channel estimation in a mobile communication system for transmitting packet data based on FDMA, and include a transmitter for transmitting signals through a pilot channel and a control channel, and a receiver for receiving the signals of the pilot channel and the control channel and estimating a channel for demodulation of a data channel using the signal of the pilot channel and information about transmission power used when the control channel is transmitted. The receiver includes a pilot channel receiver, a control channel receiver, a control channel signal reproducer, and a channel estimator for performing channel estimation using the signals received through the pilot channel, the control channel, the signal transmitted through the control channel by the transmitter, and the information about transmission power used when the control channel is transmitted by the transmitter.

Abstract: A transmission/reception method and apparatus in an Orthogonal Frequency Division Multiplexing (OFDM)-based wireless communication system are provided, in which a data transmitter adaptively selects a multiplexing scheme according to a code rate of the transmission packet or an effective SNR of a wireless channel for a corresponding terminal, when transmitting a packet data channel. The adaptive multiplexing scheme is equal in concept to a scheme of adaptively implementing unitary precoding. The unitary precoded multiplexing includes Orthogonal Frequency code Domain Multiplexing (OFCDM), Fast Fourier Transform-Spread-OFDM (FFT-S-OFDM), Fast Frequency Hopping-OFDM (FFH-OFDM), and the like. The method and apparatus adaptively selects the multiplexing scheme and transmits/receives data using the selected multiplexing scheme, thereby improving reception performance of the packet data.

Abstract: An apparatus and method are provided for transmitting and receiving a pilot signal using multiple antennas in an OFDM mobile communication system. In the pilot transmitting apparatus, at least one Walsh coverer Walsh-covers a pilot signal to be sent through each of transmit antennas. At least one transmitter allocates the Walsh-covered pilot signals to a predetermined subcarrier in every OFDM symbol and transmits the allocated pilot signals through the transmit antennas.

Abstract: A method, apparatus and system for efficiently transmitting and receiving channels are provided in a wireless communication system based on Orthogonal Frequency Division Multiplexing (OFDM). A multiplexing scheme differs according to a channel when a transmitter transmits a packet data channel, a common control channel and a control channel designated for a particular user. Uncoded 1-bit information is broadly dispersed in frequency and time domains using multiplexing technology for maximizing diversity gain in a channel for transmitting information of at least one bit to a particular user like an acknowledgement (ACK) channel. The transmitter converts a sequence obtained by multiplexing multiple bits to be transmitted to a plurality of users to parallel signals, and broadly disperses the parallel signals in the time and frequency domains.

Abstract: Provided is an apparatus for signal transmission in a Fast Frequency Hopping-Orthogonal Frequency Division Multiplexing (FFH-OFDM) communication system which divides all of the available frequency bands into a plurality of sub-carrier bands and includes a plurality of sub-channels each including at least one sub-carrier band.

Abstract: Provided is a method for configuring and managing a channel in a wireless communication system that divides a full frequency band into a plurality of sub-bands. The method comprises selecting at least one sub-band from the plurality of sub-bands and allocating each of a plurality of Adaptive Modulation and Coding (AMC) channels using the selected at least one sub-band; puncturing sub-carriers of at least one of the plurality of AMC channels according to a predetermined pattern; and allocating a diversity channel using the punctured sub-carriers.

Abstract: An apparatus for transmitting data in a frequency division multiple access based communication system is disclosed. The apparatus includes a symbol block generator for generating a symbol block in a predetermined symbol block period within one TTI when control information to be transmitted exists in the TTI, an FFT unit for performing FFT on the symbol block, and an IFFT unit for performing IFFT on signals output from the FFT unit and then transmitting the signals. The symbol block includes the control information and data to be transmitted. The TTI includes multiple symbol block periods.

Abstract: A transmitter and receiver for fast frequency hopping based on a cyclic frequency hopping pattern in an orthogonal frequency division multiplexing system. The transmitter outputs a transmission signal vector having a plurality of samples. In the receiver, a first Fast Fourier Transform (FFT) processor transforms a first received signal vector into a second received signal vector of a frequency domain by using FFT. An equalizer multiplies the received signal vector by an inverse matrix of a channel matrix representing characteristics of a channel from the transmitter to the receiver. A modified IFFT processor transforms output of the equalizer by using IFFT, and multiplies IFFT outputs of a last stage of the modified IFFT processor by predetermined gains associated with the cyclic frequency hopping pattern of the transmitter. A second FFT processor transforms output of the modified IFFT processor by using FFT to output a recovered received signal vector.

Abstract: A transmitter and receiver for fast frequency hopping (FFH) of a sample time unit in an orthogonal frequency division multiplexing (OFDM) communication system. The transmitter includes an FFH frequency modulator for converting the data elements of the data vector into a transmission signal vector that hops to a frequency in a sample time unit according to an FFH pattern of the sample time unit. The receiver includes a Fast Fourier Transform (FFF) processor for transforming a received signal vector after frequency hopping into a second received signal vector of a frequency domain by using FFT, a first equalizer for multiplying the received signal vector by an inverse matrix of a channel matrix representing characteristics of a channel from the transmitter to the receiver, and a frequency hopping recovery unit for outputting a recovered received signal vector.

Abstract: A method and apparatus for changing a Transmit Time Interval (TTI) based on a Hybrid Automatic Repeat Request (HARQ) process in a code division multiple access (CDMA) communication system that supports a packet data service through an Enhanced Uplink Dedicated transport Channel (E-DCH). According to the method and apparatus, a data transmission/reception is performed in a manner that a TTI change signal is received, the actual time point of TTI change is calculated based on the TTI change signal and the HARQ process of the previous TTI, and the TTI is changed at the calculated time point of TTI change.

Abstract: A method and apparatus for efficiently transmitting channel quality information in an OFDM communication system using dynamic channel allocation and adaptive modulation, and determining parameters required for time-division channel quality information transmission in an asynchronous CDMA communication system are provided. In the OFDM communication system in which a plurality of subcarriers are allocated to a plurality of UEs, the subcarriers are divided into a plurality of subcarrier groups each having at least one subcarrier. Each of the UEs determines and transmits the channel quality information of each of the subcarrier groups according to predetermined transmission parameters at transmission time points that do not overlap with those of other UEs. A Node B dynamically allocates the subcarriers to the UEs and their corresponding modulation schemes according to the channel quality information.