摘要:
Methods and apparatus to encode message input symbols in accordance with an accumulate-repeat-accumulate code with repetition three or four are disclosed. Block circulant matrices are used. A first method and apparatus make use of the block-circulant structure of the parity check matrix. A second method and apparatus use block-circulant generator matrices.
摘要:
An apparatus and method for encoding low-density parity check codes. Together with a repeater, an interleaver and an accumulator, the apparatus comprises a precoder, thus forming accumulate-repeat-accumulate (ARA codes). Protographs representing various types of ARA codes, including AR3A, AR4A and ARJA codes, are described. High performance is obtained when compared to the performance of current repeat-accumulate (RA) or irregular-repeat-accumulate (IRA) codes.
摘要:
Methods and apparatus to encode message input symbols in accordance with an accumulate-repeat-accumulate code with repetition three or four are disclosed. Block circulant matrices are used. A first method and apparatus make use of the block-circulant structure of the parity check matrix. A second method and apparatus use block-circulant generator matrices.
摘要:
An apparatus and method for encoding low-density parity check codes. Together with a repeater, an interleaver and an accumulator, the apparatus comprises a precoder, thus forming accumulate-repeat-accumulate (ARA codes). Protographs representing various types of ARA codes, including AR3A, AR4A and ARJA codes, are described. High performance is obtained when compared to the performance of current repeat-accumulate (RA) or irregular-repeat-accumulate (IRA) codes.
摘要:
Encoder and decoder circuits that encode and decode a series of data words to/from a series of code words. The data words include L symbols. The code words include M symbols, where M is larger than L. A set of tightly coupled M links to convey respective symbols in each of the series of code words. The code words are selected such that between every two consecutive code words in a series of code words, an equal number of transitions from low to high and high to low occur on a subset of the M-links.
摘要:
A first device includes a linear transformation circuit to implement multiplication by a matrix D. The linear transformation circuit as an input to receive a vector having N digital values and an output to output N first output signals. The linear transformation circuit optionally includes a sign-adjustment circuit to adjust signs of a subset including at least M of the N first output signals in accordance with a set of coefficients H. The linear transformation circuit includes a digital-to-analog conversion (DAC) circuit coupled to the output of the sign-adjustment circuit. Outputs from the DAC circuit are summed to produce an output.
摘要:
Embodiments of a circuit are described. In this circuit, a transmit circuit provides signals to antenna elements during an acquisition mode, where a given signal to a given antenna element includes at least two frequency components having associated phases, and where the phase of a given frequency component in the given signal is different from phases of the given frequency component for the other antenna elements. Moreover, an output node couples the transmit circuit to the antenna elements that transmit the signals. Note that these signals establish an angle of a communication path between the circuit and another circuit.
摘要:
An encoder encodes data into a series of parallel codewords. Each codeword is expressed two sets of logic values (e.g., a set of logic 0s and a set of logic 1s) on output nodes. The encoder selects a current codeword from a group of codewords in a codespace which does not overlap the other group of codewords, i.e., codewords in a given group of codewords are not included in any other group of codewords in the codespace. This property allows a receiver of the codewords to be simplified. In particular, a mathematical operation performed on symbols in the current codeword uniquely specifies the corresponding group of codewords. This allows a decoder to decode the current codeword using comparisons of symbols received on a subset of all possible combinations of node pairs.
摘要:
Each symbol in a sequence of codewords is expressed as a voltage level representative of a one or zero, and each codeword includes both levels. Sense amplifiers at the receiver compare all pairs of symbols in each codeword. Comparisons based upon like symbol values provide mid-range sensed voltages, and comparisons based upon disparate symbols values provide relatively higher or lower sensed voltages. Sampling the high and low voltages produces determinate sample values, whereas sampling the midrange voltage produces indeterminate sample values. Sampling the sensed voltages thus produces a mix of indeterminate and determinate values for each codeword. Codewords are selected such that the number and placement of the determinate sample values identify each codeword, and subsequent codewords are selected so the nodes supporting the high and low sensed voltages sampled to obtain the determinate sample values transitioned to their current voltage from either the intermediate voltage or did not transition.
摘要:
An implementation of a signaling protocol for low power and large scale wireless networks provides a media access control (MAC) that produces a low rate two-way communication link between a commercial infrastructure and a very large number of small, low-cost devices known as electronic tags. The numerous tags attached to merchandise or shelves communicate with a number of access points (AP) distributed throughout a facility containing merchandise for sale or storage. A store controller maintains the pricing database for the point of sale (POS) registers of the facility. Price changes are transmitted in real time to the tag, thus updating the merchandise tags and the point of sales (POS) registers simultaneously. The tags contain a controller and a battery in which conservation of power is crucial to the life of the tags.