112 results about "Repetition code" patented technology

A digital communications network system for multiple access has a head-end node and at least one station node at at least one other end node; the system comprises a head-end controller (3) capable of transmitting data and medium-access control information to at least one station (6), preferably a plurality of station means, over a set of downstream channels within a first frequency range, and receiving information from the station or stations over an upstream channel within a second frequency range; the upstream channel comprises at least one upstream subchannel, preferably a plurality of upstream subchannels; the system further comprises at least one connection, preferably a plurality of connections, for connecting the head-end controller with the station or stations; each station includes means for receiving data and medium-access control information from the head-end controller; further means are provided for sending a data stream at a first signal level over at least one upstream subchannel, preferably a plurality of upstream subchannels; the station further includes means for sending at least one ranging request message to the head-end controller over at least one upstream subchannel; the ranging request message of messages has/have a signal level that is lower than the first signal level of the data stream; the ranging request message or messages is/are being transmitted using repetition coding enabling the head-end controller to detect the ranging request message or messages having a signal level lower than the first signal level of the data stream; the repetition coding is selected for enhancing the level of spectral containment of the ranging request message(s) and for reducing interference with transmission over adjacent upstream subchannels.

Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors from the same transmitted vector. The symbols of the received signal vectors are combined, forming a combined received signal vector that may be treated as a single received signal vector. The combined signal vector is then decoded using a maximum-likelihood decoder. In some embodiments, the combined received signal vector may be processed prior to decoding. Systems and methods are also provided for computing soft information from a combined signal vector based on a decoding metric. Computationally intensive calculations can be extracted from the critical path and implemented in preprocessors and/or postprocessors.

The present invention relates to a multicarrier direct sequence code division multiple access (DS/CDMA) system using a turbo code with nonuniform repetition coding. In particular, it relates to a multicarrier DS/CDMA system using a turbo code with unequal diversity order in its code symbols instead of using a convolutional code.

A method includes grouping a data stream into a first plurality of subgroups, modulating a plurality of subcarriers with the first plurality of subgroups, adaptively applying a block code to said data stream comprising a repetition code, a Hamming code, and a plurality of uncoded bits based upon a channel characteristic of each of said plurality of subcarriers, and transmitting the data stream on the plurality of subcarriers.

A method of communicating data to M receiving antennas from N transmitting antennas, where M and N are integers, the method includes the steps of producing N data streams from outbound data, applying the N data streams to a space/time encoder to produce N encoded signals and transmitting the N encoded signals from N transmitting antennas. At least P transmitting antennas transmit space-time block-coded signals and (N-P) transmitting antennas transmit repetition code signals, where P is an integer. The transmission of the N encoded signals is performed such that the M receiving antennas receive at least three Orthogonal Frequency Division Multiplexing (OFDM) symbols per tone.

The invention discloses a Beidou navigation system D1 navigation message capture method. The method can adapt to all kinds of bit jump, increases the coherent integral gain, eliminates erroneous carrier frequency estimation caused by correlation peak splitting, and can be used to effectively and reliably capture a Beidou navigation system D1 navigation message. The method comprises the following steps: multiplying the signal sequence of a received D1 navigation message containing interference by a local carrier complex sequence and carrying out frequency mixing to realize carrier Doppler frequency offset stripping; then, expanding a local repetition code in two ways at the same time to obtain a local repetition code A and a local repetition code B; performing correlation operation on each of the two local repetition codes and the frequency mixing result; judging the results of the two correlation operations to obtain a carrier Doppler frequency offset estimated value fd and a ranging code phase delay estimated value Tau; and capturing the D1 navigation message.

The present invention provides systems and methods for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors from the same transmitted vector. The symbols of the received signal vectors are combine, forming a combined received signal vector that may be treated as a single received signal vector. The combined signal vector is then decoded using a maximum- likelihood decoder. In some embodiments, the combined received signal vector may be processed prior to decoding. Systems and methods are also provided for computing soft information from a combined signal vector based on a decoding metric. Computationally intensive calculations can be extracted from the critical path and implemented in preprocessors and/or postprocessors. One embodiment considers the MIMO HARQ reception using Cholesky decomposition or factoruzation of the metric.

The invention belongs to the fields of digital communication and digital storage and in particular relates to a multi-rate code encoding method for grouped Markov superposition coding based on time division. The method is used for encoding a binary information sequence u- with the length K being equal to (n-2)kBL into code words c- with the length N being equal to (n-2)nB(L+m<k>), wherein n is more than 2, k refers to a range of {1, 2,..., n-1}, namely a code rate set refers to {1/n, 2/n,..., (n-1)/n}, L is the number of (n-2)kB sequenced packets of equal length, m<k> is the memory length of subcodes with the code rate of k/n, and the memory length of an encoder is as shown in the specification. The method comprises the following steps: dividing the information sequence u- into L packets of equal length which are as shown in the specification, wherein t is equal to -1, -2,..., -(m<k>-1), -m<k>, and initializing a sequence v-(t) with the length of (n-2)nB; dividing a sequence which is as shown in the specification with the length of (n-2)kB into B packets at the moment t being equal to 0, 1,..., L-1 for performing time division encoding on [n, 1] repetition codes and [n, n-1] single parity check codes, thereby obtaining an encoding sequence which is as shown in the specification with the length of (n-2)nB; and calculating the t-th subsequence of the code words c- by combining the sequence as shown in the specification. The multi-rate codes based on time division provided by the invention are simple in design, wide in code rate range, low in decoding complexity and excellent in performance.

A receiver of a communication system includes means for receiving repetition-coded data. The receiver also includes means for generating symbol information from the received repetition-coded data. The receiver also includes means for storing symbol information over a predetermined period and means for making tentative symbol decisions by combining the stored symbol information.

The invention provides a coding method and apparatus in secondary ultrasonic communication. A plurality of frequency points in a secondary ultrasonic communication frequency band and four kinds of symbols are respectively set, wherein the four kinds of symbols respectively are a data synchronous code E, binary data "0", binary data "1", and a data repetition code "P"; to-be-sent data are determined and if two bits of identical data for continuous sending exit in the to-be-sent data, the data repetition code is used for replacing the second-bit data; the to-be-sent data are coded according to a data coding format and data frames after coding are transmitted, thereby realizing secondary ultrasonic communication. Besides, the data coding format successively includes a data communication start code, a check code, net load data, and a data transmission end mark code; and the data communication start code is formed by synthesis of the data synchronous code E and the data repetition code P. According to the invention, a problem that an error code occurs due to identical data continuous sending caused by inaccurate communication synchronization in the prior art can be solved; and the transmission accuracy rate can be improved.