6117 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.

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.

A method and apparatus for encoding and decoding data using an overall code comprising an outer parity-check and an inner parallel concatenated convolutional, or turbo code. The overall code provides error probabilities that are significantly lower than can be achieved by using turbo codes alone. The output of the inner code can be punctured to maintain the same turbo code rate as the turbo code encoding without the outer code. Multiple parity-check codes can be concatanated either serially or in parallel as outer codes. Decoding can be performed with iterative a posteriori probability (APP) decoders or with other decoders, depending on the requirements of the system. The parity-check code can be applied to a subset of the bits to achieve unequal error protection. Moreover, the techniques presented can be mapped to higher order modulation schemes to achieve improved power and bandwidth efficiency.

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.

A method and system (102) provide adaptive modulation / coding with distribution of excess resources based on one or more system criteria. The system (102) may be any system with more than one modulation rate or more than one coding rate and may be a wireless communication system using CDMA, TDMA, OFDM or any other signal formats. Generally, the method determines excess resources of the system based on desired characteristics of links supported by the system. The excess resources may be any number of system resources, such as transmit power. These excess resources are then distributed to the links based on various system criteria, such as to increase system coverage, to increase system capacity, to modify a data rate profile of the system or to reduce interference in the system. Methods for providing such distribution of the excess resources are also provided for equal data rate systems.

Low density parity check (LDPC) codes (LDPCCs) have an identical code blocklength and different code rates. At least one of the rows of a higher-rate LDPC matrix is obtained by combining a plurality of rows of a lower-rate LDPC matrix with the identical code blocklength as the higher-rate LDPC matrix.

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 method for improving a cooperation between a packetized data bit-rate adaptation and a data packet re-transmission transmits data packets from a server to a client with a first bit-rate; stores transmitted data packets in a server buffer; stores transmitted data packets in a client buffer; signals impairment information related to an impairment of transmitted data packets during transmitting to the server, wherein the signaled impairment information is analyzed by the server to decide if a re-transmission of data packets stored in the server buffer is required; and signals client buffer information related to a state of the client buffer to the server, wherein the client buffer information is analyzed by the server to decide if a re-transmission of data packets is required.

To increase the robustness of a broadcast DTV signal, complete (207, 187) Reed-Solomon forward-error-correction codewords are coded using binary linear block codes that reduce code rate by two or slightly less, enabling a DTV receiver to correct bit errors. Also, a DTV receiver can use a (15, 8), (16, 8) or (8, 4) block code to locate erroneous bytes for decoding (207, 187) Reed-Solomon code, so twice as many erroneous bytes can be corrected in a 187-byte data packet. The reduced code rate permits robust transmission of a 187-byte data packet in only two data segments and its super-robust transmission using a restricted symbol alphabet in only four data segments. This simplifies time-division multiplexing of data segments used for ordinary 8VSB transmissions with those used for robust and super-robust transmissions. Procedures to make legacy DTV receivers disregard data segments used for robust and super-robust transmission are disclosed.

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.

A family of methods for interference averaging in multicarrier systems, such as orthogonal frequency division multiplexing (OFDM) systems. The methods can provide interference averaging in situations where an interfering co-channel is either partially or fully loaded. For partially loaded systems, subcarrier puncturing, frequency domain repetition, time domain repetition, and hybrid time-frequency repetition schemes are provided. For systems using adaptive modulation / coding rates, lower rates and transmit power can be selected in order to perform interference averaging in time-spread and frequency-spread OFDM schemes. In systems with downlink power control, frequency domain mixing can be used to perform interference averaging.

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.

The invention discloses a wireless communication method, device and system. The method comprises the steps of transmitting first authorization information to a first communication device and / or a second communication device, and enabling the second communication device to transmit second authorization information to the first communication device; enabling the first authorization information to at least comprise first resource distribution information for distributing resources; enabling the second authorization information to at least comprise a modulation mode for indicating business data and a modulation coding mode for a code rate; enabling the second communication device to transmit the business data to the first communication device in distributed resources, or enabling the first communication device to transmit the business data to the second communication device in the distributed resources. According to the wireless communication method and device, the problem of inefficiency in transmission and scheduling in device-to-device (D2D) communication is solved, control signaling spending is reduced relative to cellular communication, and the resource utilization rate in device-to-device communication is guaranteed.

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.

Two levels of error correction decoding are performed using first and second level decoders. A composite code formed by combining an inner component code and an outer component code can be used to decode the data and correct any errors. Performing two level decoding using a composite code allows the size of the inner parity block to be reduced to a single Reed-Solomon symbol while keeping a good code rate. The first level decoder generates soft information. The soft information can indicate a most likely error event for each possible syndrome value of the inner component code. The soft information can also include error metric values for each of the most likely error events. The second level decoder generates corrected syndrome values based on the soft information using the outer component code. The most likely trellis path that corresponds to the corrected syndrome values is then selected.

The invention discloses a method for downloading a media file in a content distribution network and a client. By means of method, the client can normally receive a service when a bandwidth changes, and burden is not brought to file management; and the method is easy to implement. The media file is partitioned into a plurality of virtual fragments according to fixed duration. The method comprises the following steps: the client downloads the primary index of media contents requested by a user for broadcasting, from a server, wherein secondary index addresses for media files at different code rates in specific to the media contents are recorded in the primary index; the client selects a code rate and downloads the secondary index of a media file at the selected code rate from the server according to the contents of the primary index, wherein the secondary index comprises the first address of the media file and time information relevant to the virtual segments in the media file; and the client downloads a corresponding media file from the server according to the secondary index and records the quantity of downloaded virtual segments according to the time information in a media file downloading process.

The disclosed technology provides systems and methods for encoding data based on a run-length-limited code and an error correction code to provide codewords. The codewords include RLL-encoded data that are produced based on the RLL code, and parity information that are produced based on the error correction code. The parity information is interleaved among the RLL-encoded data. In one embodiment, the codeword is produced by separately producing the RLL-encoded data and the parity information, and interleaving the parity information among the RLL-encoded data. In one embodiment, the codeword is produced by producing the RLL-encoded data, and using erasure decoding to compute the parity information.

A parallel concatenated low density parity check (LDPC) code having a variable code rate is provided by generating, upon receiving information bits, a first component LDPC code according to the information bits, interleaving the information bits according to a predetermined interleaving rule, and generating a second component LDPC code according to the interleaved information bits. With use of the parallel concatenated LDPC code, a mobile communication system can use a Hybrid Automatic Retransmission Request (HARQ) scheme and an Adaptive Modulation and Coding (AMC) scheme without restriction.

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.

An error correction encoding rate selection table is provided in an error correction processing unit of a packet transfer apparatus, and the table stores an error correction encoding rate preset to maintain a desired QoS in correspondence with a protocol type and an application type. When a transmission packet is transferred to a wireless transmission path, an encoding control unit judges the protocol type and application type of a transmission packet from a header of the transmission packet, in accordance with a judgment result and the error correction encoding rate selection table, an error correction encoding rate is selected, and the transmission packet is subjected to error correction encoding and transferred.

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.