1066 results about "Channel code" patented technology

Carrier Interferometry (CI) provides wideband transmission protocols with frequency-band selectivity to improve interference rejection, reduce multipath fading, and enable operation across non-continuous frequency bands. Direct-sequence protocols, such as DS-CDMA, are provided with CI to greatly improve performance and reduce transceiver complexity. CI introduces families of orthogonal polyphase codes that can be used for channel coding, spreading, and/or multiple access. Unlike conventional DS-CDMA, CI coding is not necessary for energy spreading because a set of CI carriers has an inherently wide aggregate bandwidth. Instead, CI codes are used for channelization, energy smoothing in the frequency domain, and interference suppression. CI-based ultra-wideband protocols are implemented via frequency-domain processing to reduce synchronization problems, transceiver complexity, and poor multipath performance of conventional ultra-wideband systems. CI allows wideband protocols to be implemented with space-frequency processing and other array-processing techniques to provide either or both diversity combining and sub-space processing. CI also enables spatial processing without antenna arrays. Even the bandwidth efficiency of multicarrier protocols is greatly enhanced with CI. CI-based wavelets avoid time and frequency resolution trade-offs associated with conventional wavelet processing. CI-based Fourier transforms eliminate all multiplications, which greatly simplifies multi-frequency processing. The quantum-wave principles of CI improve all types of baseband and radio processing.

A system and method are disclosed for the management of WLANs in cases where unmanaged access points are present as well as with the addition or removal of access points. The disclosed system and method use signal data and network traffic statistics collected by mobile units to determine optimal configuration settings for the access points. The access point settings so managed can include the operating channel or center frequency, orthogonal signal coding used (optionally including the data rate), if any, and the transmission power. The solutions computed can account for the inherent trade-offs between wireless network coverage area and mutual interference that may arises when two or more access points use the same or overlapping frequency bands or channels and the same or similar signal coding.

Obtaining channel quality information in a wireless communication network is described. A base station allocates a resource to remote stations in order to receive channel quality information back from remote stations. The resource allocated to a remote station contains no higher layer data. A scheduler in the base station uses the channel quality information in order to schedule remote stations and/or to decide on the channel coding and/or modulation to be applied to the data transmission. A mechanism is provided to ensure that data transmitted on HS-DSCH is not transmitted to higher layers. This may provide a convenient method of obtaining channel quality information allowing for improved scheduling and thus improved performance of the communication system.

The present invention is related to a method and apparatus for implementing space frequency block coding (SFBC) in an orthogonal frequency division multiplexing (OFDM) wireless communication system. The present invention is applicable to both a closed loop mode and an open loop mode. In the closed loop mode, power loading and eigen-beamforming are performed based on channel state information (CSI). A channel coded data stream is multiplexed into two or more data streams. Power loading is performed based on the CSI on each of the multiplexed data streams. SFBC encoding is performed on the data streams for each of the paired subcarriers. Then, eigen-beamforming is performed based on the CSI to distribute eigenbeams to multiple transmit antennas. The power loading may be performed on two or more SFBC encoding blocks or on each eigenmodes. Additionally, the power loading may be performed across subcarriers or subcarrier groups for weak eigenmodes.

The subscriber station of claim 15, wherein the uplink data includes data to be transmitted, and a header having information on the data and the subscriber, and the uplink data generator adds the subheader includDisclosed is a method and device for requesting and reporting channel quality information in a mobile communication system. An uplink radio resource for a subscriber station having data to transmit is allocated and a CQI indicator for requesting channel quality information is added to the allocation information to be transmitted to a subscriber station. The subscriber station having received the uplink radio resource allocation information generates channel quality information by measuring the radio channel quality for communication with the base station according to existence of the indicator and transmits desired uplink data having the generated channel quality information to the base station. As a result, the seamless and efficient channel quality report can be performed in the wireless communication system, and the optical modulation and the channel coding level can be adapted for the subscriber to transmit or receive the data corresponding to the channel quality. ing the channel quality information to the header of the uplink data.

Disclosed is a digital communication system. A transmission system includes an error correction encoder part carrying out an error correction encoding for additional data inputted through a first path, a multiplexer (MUX) part, a control part, a channel coding part carrying out an RS encoding and a TCM encoding, and a VSB transmission part modulating the channel-coded data by a VSB method and outputting the modulated data. A receiver system includes a tuner part receiving and tuning additional data and ATSC data transmitted through a same channel, a TCM decoder decoding and outputting the ATSC data and additional data, a deinterleaver deinterleaving data outputted from the TCM decoder, a demultiplexer demultiplexing along a first path (ATSC) or a second path (additional data) in accordance with a kind of output data of the deinterleaver, a limiter carrying out a hard decision on data outputted by the first path, an ATSC decoder part including a derandomizer, and an additional error correction decoder part decoding additional-error-encoded data on additional data outputted through the second path.

A data transmission method for a MIMO (Multiple-input Multiple-Output) system allowing multiple terminals to share channelization codes according to the channel states, by receiving channel information from terminals, allocating channelization codes for each transmit antenna based upon the received channel information, and transmitting data via each transmit antenna according to the allocated channelization codes. When there are many user terminals and if the number of channelization codes are limited, namely, when the total number of channel codes used to distinguish the terminals is less than the total number of terminals, channelization code sharing per transmit antenna among multiple terminals is performed, such that the throughput of data that can be sent by using each channelization code is increased.

The universal forward error-correction coding system provides adjustable code rates and coding gains to greatly benefit the design of many modern digital communications (data storage) systems. The channel encoding and decoding methods are universal such that a single encoder and a single decoder can be used to implement all the forward error-correction codes of different code rates. This universal forward error-correction coding system also includes a novel systematic code generation procedure that has the capability of generating many classes of codes that provide the best balance between coding gain performance and implementation complexity.

A method and apparatus for increasing the data rate and providing antenna diversity using multiple transmit antennas is disclosed. A set of bits of a digital signal are used to generate a codeword. Codewords are provided according to a channel code. Delay elements may be provided in antenna output channels, or with suitable code construction delay may be omitted. n signals represent n symbols of a codeword are transmitted with n different transmit antennas. At the receiver MLSE or other decoding is used to decode the noisy received sequence. The parallel transmission and channel coding enables an increase the data rate over previous techniques, and recovery even under fading conditions. The channel coding may be concatenated with error correction codes under appropriate conditions.

Provided are a cell search method, a frame transmission method thereof, and a forward link frame structure thereof. The cell search method used by a terminal to search a target cell using reception signals received from a plurality of base stations, each base station transmitting a frame of its cell, in an Orthogonal Frequency-Division Multiplexing (OFDM) cellular system comprising a plurality cells to which a cell-specific scrambling code is assigned includes: detecting a hopping pattern of the target cell using reception sync channel symbols, which are signals corresponding to sync channel symbol positions of the reception signals, wherein the frame of each cell comprises M sync channel symbols code-hopped according to a hopping pattern of the cell, where M is a natural number equal to or greater than 2, each hopping pattern containing M sync channel code sequences and respectively corresponding to each code group to which a scrambling code of each cell belongs, and an arbitrary hopping pattern used in the OFDM cellular system differs from a cyclically shifted result of the hopping pattern, other hopping patterns, or cyclically shifted results of the other hopping patterns; and detecting a code group of the target cell based on the detected hopping pattern. Accordingly, a cell search time and the complexity of the cell search can be reduced.

A transmission apparatus in a Multiple Input Multiple Output (MIMO)-based wireless communication system. The transmission apparatus includes at least two antenna groups each having at least two antennas, wherein the antenna groups are spaced apart by a first distance and transmit antennas in each antenna group are spaced apart by a second distance which is shorter than the first distance. A channel coding and modulation unit channel-codes and modulates a desired transmission data stream. A precoding unit precodes the channel-coded and modulated signal separately for each antenna group and each antenna in the same antenna group. Thereafter, a transmission processing unit transmission-processes the output signal from the precoding unit.

The present invention discloses a method for channel coding and modulation mapping in HARQ of the LDPC code, comprising: performing structural LDPC encoding of an information bit sequence with a length of K input by a channel encoder, and sending a generated codeword to a HARQ buffer; rearranging codeword bits of a LDPC HARQ mother code in the HARQ buffer, and sequentially selecting codeword bits to generate a binary sequence of a HARQ packet; mapping codeword bits of the HARQ packet to a constellation, and high-order bits in encoding blocks of the HARQ packet being mapped to high reliability bits in the constellation. The present invention provides the LDPC codeword with the maximal constellation gain, so that the LDPC HARQ channel encoding has the optimal performance.

A transmitter includes: a data modulation and channel coding unit configured to perform data modulation and channel coding for a data channel with a modulation level and a channel coding rate updated for each transmission time interval; a multiplexing unit configured to multiplex a control channel and the data channel for each transmission time interval; and an adjusting means configured to adjust a length of the transmission time interval. Increasing a unit of information transmission in the time direction and/or the frequency direction depending on communication conditions can reduce a frequency of inserting (allocating) the control channel, and can improve data transmission efficiency.

A method and device for transmitting a first and second uplink signal, each having data and control information is provided. The method includes channel encoding the control information of the second uplink signal based on a number of symbols of control information to produce. The channel encoding includes determining the number of symbols in accordance with a payload size of the data of the first uplink signal and a total number of transmissible symbols of a Physical Uplink Shared Channel (PUSCH) of the first uplink signal.

A method and apparatus for generating Low-Density Parity Check (LDPC) codes of various block lengths from a structured LDPC code in a communication system is provided. To support various block lengths, predefined rules are applied to a parity check matrix of an LDPC code, and then shortening is selectively applied to the parity check matrix. Subsequently, if information data bits are input, the input data information bits are encoded into an LDPC codeword by using the parity check matrix according to a preset encoding scheme, and then the encoded LDPC codeword is transmitted after puncturing is selectively applied.

A channel encoding apparatus using a parallel concatenated low density parity check (LDPC) code. A first LDPC encoder generates a first component LDPC code according to information bits received. An interleaver interleaves the information bits according to a predetermined interleaving rule. A second LDPC encoder generates a second component LDPC code according to the interleaved information bits. A controller performs a control operation such that the information bits, the first component LDPC code which is first parity bits corresponding to the information bits, and the second component LDPC code which is second parity bits corresponding to the information bits are combined according to a predetermined code rate.

The present invention relates to a transmitter in an OFDM system for improving the PAPR, and a method thereof. According to the exemplary embodiment of the present invention, channel encoding is performed in order to correct a data transmission error of a radio channel, a predetermined bit of the channel encoded data is bit-inverted by using a mask bit or a mask bit sequence, and a PAPR of the signal is reduced. Accordingly, reduction of transmission efficiency which has been generated in block coding and DSI methods is not generated when the signal is transmitted because an additional bit is not required.

A coding system and method for a terminal including a multi-rate codec is disclosed. The terminal includes a multi-rate adaptive coder that is capable of transmitting a continuous voice stream transmission at a source code bit rate and a channel code bit rate. A quality of service probing module probes an end-to-end network path of the continuous voice stream transmission to obtain at least one quality of service parameter. A quality of service management module determines at least one constraint associated with the continuous voice stream transmission. An adaptive bit rate algorithm module dynamically adjusts the source code bit rate and the channel code bit rate as a function of the quality of service parameter and the constraint to obtain a maximum value of perceived user performance during the continuous voice stream transmission.

An encryption technique allowing use of classic Y-00 scheme performed using classic physical random numbers instead of quantum fluctuation in electrical communication and data storage in recording media, including a first modulation step for multilevel-modulating input data by associating with specific state pairs determined by physical random numbers, a second modulation step for outputting the output of the first step by irregularly associating with another signal by physical random numbers, and a channel coding step for channel-coding the output of the second step into desired codeword and outputting it as encrypted data, wherein the decoded signal obtained by channel-decoding the encrypted data can be discriminated which of specific state pairs the signal corresponds to and demodulated into the input data, and output by the first modulation by state pairs other than the specific state pairs and the second modulation by a physical random number different from the physical random number.

Disclosed are an apparatus and a method capable of preventing performance degradation during a channel decoding process. A bit interleaving is performed with respect to parity bits among coded bits output through a channel coding unit, thereby preventing a repetition period of the parity bits from matching a puncturing period for a rate matching. A bit de-interleaving is performed with respect to the parity bits during a channel decoding process, so that the parity bits have a repetition period identical to initial parity bits. Thus, the repetition period of the parity bits is not matched with the puncturing period for the rate matching, thereby preventing performance degradation during the channel decoding process.

A method for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code is provided. The method includes determining a number of parity bits for puncturing; dividing the parity bits at predetermined intervals, and determining a number of puncturing parity bits, which are subjected to puncturing within the predetermined intervals; determining a modulation scheme; determining positions of puncturing parity bits corresponding to the determined number of the puncturing parity bits within the predetermined intervals according to the modulation scheme; repeatedly performing puncturing on puncturing parity bits corresponding to the determined positions at the predetermined intervals; and transmitting remaining bits except for the punctured bits according to the modulation scheme.

A buffer 106 stores transmission data temporarily. A CQI transmission control section 113 outputs an instruction signal for generating CQI to a CQI generating section 107 when transmission data is accumulated in buffer 106. CQI generating section 107 generates CQI based on quality information when the instruction signal is input from CQI transmission control section 113, and does not generate CQI when the instruction signal is not input from CQI transmission control section 113. A base station information extracting section 108 extracts transmit parameter information and scheduling information included in received data. A channel coding section 109 encodes transmission data based on encoding rate information in the transmit parameter information. A modulator 110 modulates the transmission data based on modulation scheme information in the transmit parameter information. By this means, a large volume of packet data can be communicated at high speed on the uplink in optimum conditions according to communication environment.