摘要:
A method includes determining one or more metrics indicative of at least one of (i) interference on a communication link, (ii) noise on the communication link, and (iii) performance of a receiver receiving packets via the communication link, selecting a modulation and coding scheme as a function of (i) the determined one or more metrics, and (ii) one or more Quality of Service requirements for the communication link, and correcting the selected modulation and coding scheme using a current value of a correction factor. The corrected modulation and coding scheme is to be used to generate one or more packets. The method also includes determining an error rate corresponding to packets previously transmitted over the communication link, and adjusting the correction factor based on the determined error rate. Adjusting the correction factor includes incrementing or decrementing the correction factor.
摘要:
Systems and methods are provided for computing soft information for digital information based on a received signal, where the received signal suffers from noise and interference. A receiver that decodes the received signal may estimate channel information, such as the channel gain, associated with the interfering source. The receiver may also obtain modulation information through a backbone network or by decoding control information transmitted by the interfering source. Using the modulation information and the channel information, the receiver may estimate the effect that interference has on the received signal, and may compute soft information (e.g., a log-likelihood ratio) for the digital information.
摘要:
In a method for synchronizing a receiver to a synchronous signal, in a signal having been processed based on an automatic gain control (AGC) with a varying gain, a symbol is detected. An estimated beginning of a subsequent frame is determined based on the detected symbol. A gain of the AGC is fixed for a period during which the estimated start of the subsequent frame is processed by the AGC. A transform of the signal is analyzed to determine if the estimated start of the subsequent frame corresponds to an actual start of the subsequent frame. If the estimated start of the subsequent frame does not corresponds to the actual start of the subsequent frame, the gain of the AGC is allowed to resume varying and, a further symbol in the signal is detected, the signal having been processed based on the varying gain of the AGC.
摘要:
In a wireless communication system wherein communication devices exchange information utilizing data units that conform to a first format, a beamforming training (BFT) data unit that conforms to a second format is transmitted, wherein a length of the BFT data unit is shorter than lengths supported by the first format, wherein the BFT data unit is for transmitting PHY beamforming training information. Information to indicate the BFT data unit conforms to the second format is transmitted to a receiving device. The BFT data unit is generated according to the second format, wherein the BFT data unit includes BFT information elements. The BFT data unit is then transmitted to the receiving device.
摘要:
Methods, software, circuits and systems involving a low complexity, tailbiting decoder. In various embodiments, the method relates to concatenating an initial and/or terminal subblock of the serial data block and outputting decoded data from an internal block of the modified data block. The circuitry generally includes a buffer, logic configured to concatenate an initial and/or terminal subblock to the serial data block, and a decoder configured to decode the data block, estimate starting and ending states for the data block, and output an internal portion of the serial data block and the one or more sequences as decoded data. The invention advantageously reduces the complexity of a suboptimal convolutional decoder, ensures smooth transitions at the beginning and end of the serial data block during decoding, and increases the reliability of the starting and ending states, without adding overhead to the transmitted data block.
摘要:
In a method for decoding plurality of information streams corresponding to a plurality of layers, where the plurality of information streams have been transmitted via a multiple input multiple output (MIMO) communication channel, a plurality of received signals are processed to decode information corresponding to a first layer. A plurality of modified received signals are generated using the decoded information corresponding to the first layer and the plurality of received signals. Bit metric values are generated for a second layer using MIMO maximum likelihood (ML) demodulation and using the plurality of modified received signals and channel and modulation information for interfering signals. Information corresponding to the second layer is decoded using the generated bit metric values.
摘要:
A method including: receiving, through a wireless channel, a plurality of modulated signals at a plurality of antennas, wherein each antenna receives a corresponding modulated signal; generating a plurality of autocorrelated signals by autocorrelating the plurality of modulated signals; determining whether a signal strength associated with each modulated signal is (i) below a threshold or (ii) above the threshold; for each modulated signal having a signal strength below the threshold, disabling the antenna that received the modulated signal having the signal strength below the threshold; combining the modulated signals having a signal strength above the threshold; generating weighted autocorrelated signals based on (i) the plurality of autocorrelated signals and (ii) the combined modulated signals; generating a combined weighted signal by summing the weighted autocorrelation signals; demodulating the combined weighted signal; and determining a state of the wireless channel based on the demodulation of the combined weighted signal.
摘要:
An adaptive receiver comprises a receiver module that receives an orthogonal frequency division multiplexing (OFDM) signal. An operating parameters module monitors at least one operating parameter of the receiver module and generates a select signal based the at least one operating parameter. An estimator module selects between first and second algorithms based on the select signal and selectively estimates a carrier frequency offset (CFO) of the OFDM signal using the one of the first and second algorithms. Alternately, an estimator module adjusts algorithm operating parameters of a first algorithm based on the select signal and selectively estimates a carrier frequency offset (CFO) of the OFDM signal using the selected algorithm operating parameters of the first algorithm.
摘要:
Techniques are provided for detecting a coded signal in the presence of interference. In an embodiment, a primary transmitter corresponds to a desired transmitter, and one or more secondary transmitters correspond to interfering transmitters. Received symbols, which include interference and additive noise, are filtered to recover a set of original message bits. An estimate of the set of original message bits may be determined using an ordered successive interference cancellation (SIC) decoder that uses either a SIC detector or an AWGN-based detector, depending on the signal-to-interference ratio at a primary receiver.
摘要:
A system including a differential demodulation module, a first summing module, and a second summing module. The differential demodulation module generates differentially demodulated signals based on having differentially demodulated received signals. The first summing module generates a combined signal by adding the differentially demodulated signals, wherein the combined signal includes a plurality of symbols. The second summing module generates a plurality of sums for each of a plurality of derived preamble sequences, wherein the derived preamble sequences are derived from preamble sequences, and wherein each of the derived preamble sequences includes a plurality of derived symbols. The second summing module further generates cross-correlation values for the derived preamble sequences based on the plurality of sums, wherein one of the cross-correlation values generated for one of the derived preamble sequences is a sum of the plurality of sums generated for the one of the derived preamble sequences.