6055 results about "Code rate" patented technology

Coding techniques for a (e.g., OFDM) communication system capable of transmitting data on a number of "transmission channels" at different information bit rates based on the channels' achieved SNR. A base code is used in combination with common or variable puncturing to achieve different coding rates required by the transmission channels. The data (i.e., information bits) for a data transmission is encoded with the base code, and the coded bits for each channel (or group of channels with the similar transmission capabilities) are punctured to achieve the required coding rate. The coded bits may be interleaved (e.g., to combat fading and remove correlation between coded bits in each modulation symbol) prior to puncturing. The unpunctured coded bits are grouped into non-binary symbols and mapped to modulation symbols (e.g., using Gray mapping). The modulation symbol may be "pre-conditioned" and prior to transmission.

Embodiments are directed to transmitting L1 pre-signaling information with predetermined modulation and code rate such that L1 pre-signaling information can be received without preliminary knowledge on the network. L1 pre-signaling information makes it possible to receive the L1 signaling information, data link layer information, and notification data that may have configurable code rates and modulation. Therefore, L1 pre-signaling information can be thought of as signaling metadata (i.e., information about other signaling information). L1 signaling is divided into pre-signaling and signaling parts. The pre-signaling part includes parameters used for receiving the L1 signaling information. L1 pre-signaling signaling enables the receiver to receive the signaling itself (L1 signaling and data link layer information) by informing the receiver about the type of modulation, coding, and the like, used to transmit the L1 signaling, data link layer, and notification information.

Embodiments are directed to mapping Physical Layer Pipes (PLPs) with the service_id and with components of a service through the Program Map Table (PMT). A descriptor may be defined for this purpose. In accordance with one or more embodiments, a PLP_identifier_descriptor may contain an identifier for a physical layer pipe (PLP_id). In addition, several other PLP related parameters may be carried within the PLP_identifier_descriptor, instead of carrying the parameters in OSI Layer 1. The PLP_identifier_descriptor may be carried in several different tables, including, but not limited to, a Program Map Table (PMT). The PLP_identifier_descriptor may include a physical layer pipe identifier and, optionally, parameters for modulation, code rate, and FEC block type. A receiver, in accordance with embodiments, may be able to access the actual service content based on a combination of the L1 signalling information, legacy PSI/SI information, and the signalling information set forth in the PLP_identifier_descriptor.

An enhanced 8-VSB reception system and E8-VSB data demultiplexing method, by which an E8-VSB signal can be stably received as well as a previous ATSC 8VSB signal, is disclosed. Herein, the enhanced data are coded at ½ code rate and ¼ code rate in the new E8-VSB transmission system compatible with the conventional ATSC 8VSB system, respectively. The ½ and ¼ enhanced data are multiplexed by 164-byte packet unit according to the previously determined multiplexing format and further pre-processed to output as the format of the MPEG transport packet. And, the pre-processed enhanced data and the main data are multiplexed again by 188-byte packet unit according to the previously determined multiplexing format. The E8-VSB map information, which was inserted in the field sync section in the E8-VSB transmission system to be transmitted, is extracted to generate the information indicating the attributes of the respective E8-VSB data. The normal data, ½ enhanced data, and ½ enhanced data are separated from each other to be decoded in the channel decoder.

The invention discloses a motion vector forecasting method in a resolution quantizing structure, wherein, forecasting motion vectors of macro blocks in enhancement layers are acquired by utilization of relativity of motion vectors of a time domain, a space domain and an interlayer domain. The realization process is that: on the time domain, candidate motion vectors of the time domain are acquired from motion vectors of macro blocks with the same position with the prior frame; on the space domain, candidate motion vectors of the space domain are acquired from motion vectors of adjacent blocks; on the interlayer domain, candidate motion vectors of the interlayer domain are acquired from corresponding motion vectors with low space domain resolution hierarchy; candidate motion vectors with minimum motion estimation cost are selected to be forecasting motion vectors by selection among the candidate motion vectors of the time domain, the space domain and the interlayer domain. The invention has the advantages of capability of acquiring more accurate forecasting motion vectors, capability of compressing code rate of motion vectors, and obtaining of performance gain.

A method for controlling errors in a wireless link layer using a simultaneous multiple copy scheme and an adaptive forward error correction (FEC) scheme in a wideband wireless communication is provided. The method for controlling errors in a link layer in wideband wireless communication using an automatic repeat request (ARQ) scheme, in which a wideband wireless channel is used for communication between a first node and a second node, includes the steps of (a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel using the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel, and transmitting a cell, in which a forward error correction (FEC) code having an encoding ratio that varies depending on the estimated error ratio is included in a protocol data unit (PDU) of a wireless link layer, through the forward channel and (b) re-transmitting the copy of a cell transmitted in the step (a), when feedback information that indicates that an error exists in the cell transmitted in the step (a) is received through the backward channel. It is possible to reduce the number of times of re-transmission by improving the probability of correcting forward errors using more error controlling bits as the state of the channel is worse and to minimize the waste of resources using less error controlling bits as the state of the channel is better, to thus obtain the optimal performance and guarantee the minimum delay time.

A forward link device of a multicarrier CDMA communication system with an overlay scheme in which a multicarrier system and an IS-95 system share same frequency bands. In the forward link device, four encoders encode input data of corresponding rates with a 1/3 coding rate, respectively. A first repeater repeats two times full rate symbols output from the first encoder, and second to fourth repeaters repeat symbols output from the second to fourth encoders, respectively, according to a predetermined number of times, to match the number of corresponding output symbols to the number of full rate symbols. First to fourth interleavers interleave the symbols output from the first to fourth repeaters, respectively, to uniformly distribute the symbols of the same data bit to the carriers.

A communications transceiver for transmitting and receiving coded communications, with the coding corresponding to a low-density parity check code, is disclosed. A set of available code word lengths and code rates are to be supported by the transceiver. These available code word lengths and code rates are implemented as a subset of starting code word lengths, which are length-reduced by shortening and puncturing selected bit positions in the starting code word length to attain the desired one of the available code word lengths and code rates. The bit positions to be shortened and punctured are selected in a manner that avoids interference between the shortened and punctured bit positions, and that attains excellent code performance.

Aspects of a method and system for rate selection algorithm to maximize throughput in closed loop multiple input multiple output (MIMO) wireless local area network (WLAN) system are provided and may comprise computing a maximum number of binary bits to be simultaneously transmitted via an RF channel based on signal quality. A modulation technique may be selected based on the computed maximum, communicating feedback information comprising the selected modulation technique. Subsequently transmitted data may be received via an RF channel which is modulated based on the feedback information. Another aspect of the method may comprise receiving feedback information comprising at least one of a selected modulation technique and coding rate via an RF channel, and transmitting subsequent data via said at least one of a plurality of RF channels which either modulated, or coded, based on the feedback information.

In one embodiment, a method for generating an adaptive air interface waveform includes generating a waveform that includes a variable carrier frequency and variable bandwidth signal. The variable bandwidth signal includes one or more subcarriers that are dynamically placeable over a range of frequencies, and each subcarrier is separately modulated according to a direct sequence (DS) spread spectrum (SS) technique. The waveform has an embedded pilot usable to optimize one or more spectrum efficiencies of the waveform. A modulation constellation, a code rate, and a code length of the generated waveform are adapted according to an available spectrum and one or more sub-carrier conditions.

An apparatus and method for generating an encoding matrix for a low density parity check (LDPC) code having a dual-diagonal matrix as a parity check matrix are disclosed. The apparatus and method construct an information sub-matrix of the encoding matrix with a predetermined number of square matrixes according to a predetermined code rate such that each of the square matrixes has columns and rows with a weight of 1 and has a different offset value, combine the square matrixes with the dual-diagonal matrix, and perform inter-row permutation on the information sub-matrix.

A system, computer readable program, and method for programming flash memory, the method includes: providing multiple pairs of most significant bit (MSB) page uncoded bit error rates (UBERs) and least significant bit (LSB) page UBERs; selecting a selected MSB page code rate and a selected LSB page code rate so that a selected MSB page UBER associated with the selected MSB page code rate and a selected LSB page UBER associated with the selected LSB page code rate support a highest average UBER out of the multiple pairs of MSB page UBERs and LSB page UBERs, wherein the selected MSB page code rate and the selected LSB page code rate are obtainable under a desired code rate constraint; and determining an encoding and programming scheme that may be based on the selected MSB page UBER, the selected MSB code rate, the selected LSB page UBER and the selected LSB code rate.

Data are encoded using convolutional coding prior to storage in a nonvolatile memory array, so that errors that occur when the data are read may be corrected even where there is a large number of such errors. Coding rates of less than one increase the amount of data to be stored but allow correction of large numbers of errors.

A method of generating a parity-check matrix of a low density parity-check (LDPC) code with a variable information length and a variable code rate, an encoding/decoding method, and an apparatus using the same are provided. The method of generating a parity-check matrix of an LDPC code includes: a first parity-check matrix generation process of generating a first parity-check matrix constructed with a first information block and a parity block; and an m-th parity-check matrix generation process of generating an m-th parity-check matrix by an m-th information block to a generated (m−1)-th parity-check matrix (1<m≦M, where M is a natural number equal to or greater than two). Accordingly, it is possible to provide an LDPC code with a variable information length and a variable code rate which has a low complexity for encoding/decoding and a high quality of correction and detection of errors.

A method of mobile communication including a transmitter having multiple transmitters and a receiver having multiple receivers. The method includes adding a cyclic redundancy check (CRC) code to a data block to be transmitted and spatially segmenting the data block according to a modulation scheme and a coding rate of each respective transmit antenna of the multiple antennas.

Apparatus, and an associated method, for allocating communication data for communication in a multi-channel communication system, such as an OFDM system. An adaptive bit, power, and code rate scheme for a sending station that utilizes LDPC codes selects together bit, power, and code rates of data that are to be communicated upon different ones of the channels in manners that optimize a selected performance criteria.

The present invention discloses a system and method for rate control of MPEG video streams to achieve a target bit rate in a transcoder at the best visual quality possible. The invention monitors video buffer fullness for selecting the amount of rate reduction necessary to achieve a target bit rate. The invention also utilizes a method for selective requantization of DCT coefficients to assure visual quality.