Abstract: A fire-fighting device can cool a vertical wall where a horizontally-extending profiled element is disposed on the vertical wall. The fire-fighting device may comprise a guide plate that includes a first region arranged above the horizontally-extending profiled element, a second region arranged below the horizontally-extending profiled element, a third region arranged in a plane of the horizontally-extending profiled element and on a side of the horizontally-extending profiled element facing away from the vertical wall, and a fourth region in the second region. The guide plate may have a distance to the wall of 1 mm to 20 mm in the fourth region.

Abstract: A method and a receiver system for subcarrier-specific frequency offset correction including frequency offset estimation, updating and compensation. The method includes initial frequency offset estimation in time domain using packet preamble, frequency offset compensation during channel estimation symbols using the initial frequency offset estimate, and frequency offset update tracking during header and data part both being performed in the frequency domain. The initial frequency offset estimation includes using a sum over a number of time lagged autocorrelation results, corresponding to a number of the last consecutive symbols of the preamble part of the packet with the autocorrelations being the result of a sum over a window of cross-correlations between the incoming signal and the respective packet synchronization sequence.

Abstract: Pairs of parallel Viterbi decoders use windowed block data for decoding data at rates above 320 Mbps. Memory banks of the deinterleavers feeding the decoders operate such that some are receiving data while others are sending data to the decoders. Parallel input streams to every pair of decoders overlap for several traceback lengths of the decoder causing data input to a first decoder at the end of an input stream to be the same as the data input to a second decoder of the same pair at the beginning of an input stream. Then, the first decoder is able to post-synchronize its path metric with the second decoder and the second decoder is able to pre-synchronize its path metric with the first. Either, the deinterleaver data length is an integer multiple of the traceback length or the data input to only the first block of the first interleaver is padded.

Abstract: Frame synchronization methods and systems suited for packet communications systems, and particularly time frequency hopping packet communication systems, are disclosed. Frame synchronization is performed by performing a first correlation on information of received symbols and performing a second correlation on results of the first correlation. In systems with repeating synchronization information modulated by a cover sequence, the results of the second correlation may be used to determine symbol numbering of symbols in a packet.

Abstract: Method and system for extracting soft estimates of DCM or 16-QAM modulated symbols that are received from a noisy channel. Optimal soft demapping rules are approximated using equations that are division-free and eliminate the need for implementing exponential and logarithmic functions that are inconvenient for hardware implementation.

Abstract: A method and system for estimating DC offset and removing the excess DC offset from samples used by an overlap-and-add operation at the receiver of OFDM symbols in UWB communication. The DC offset for each sample within the overlap-and-add interval may be estimated using a sliding window, of the size required for an FFT, operation over past samples. The DC offset may be estimated for a sample within the overlap-and-add interval and updated for the succeeding samples. A size of the overlap-and-add interval may be fixed or may be allowed to vary according to switching characteristics of an analog RF stage preceding the overlap-and-add operation.

Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: A method and system for removing frequencies interfering with a UWB OFDM receiver from transmission frequencies of the UWB communication. A sensing mechanism is added to the receiver that develops an energy histogram for the frequencies in a received signal and develops a tone mask for masking the interfering frequencies. The tone mask is applied after a mapping stage in the transmitter of the UWB communication and removes the interfering frequencies from the transmitted signal. Various criteria based on energy averaging are used to identify and null and remove the interfering frequencies.

Abstract: An apparatus for and a method of performing packet detection in a receiver is provided. The apparatus is configured to determine a measure of a correlation between information of one or more received symbols and synchronization information. The apparatus is also configured to determine a measure of an energy value of one or more of the received symbols. The apparatus is also configured to determine if a packet has been detected based on the measure of the correlation and the measure of the energy value of the one or more received symbols.

Abstract: Architectures for ultrawideband transmitters and receivers including parallel processing chains. Some embodiments include a two byte interface with a MAC, and some embodiments include mappers mapping I-channel and Q-channel information from separate encoders.

Abstract: Systems and methods for packet detection for frequency hopping networks. Multiple receiver chains are set to different frequencies to check for packets at the different frequencies, at least until receipt of a preamble sequence in a packet is received. After detection of a packet at least some of the receiver chains are used to process received signals according to a frequency hopping pattern.

Abstract: Methods and systems using information derived during a signaling period of a scheduling-based Medium Access Control protocol to adjust operation effective during data transmission periods. For example, channel estimation and transmission power adjustments are made based on indications provided by received signals.

Abstract: A method for determining antenna usage in a multiple input multiple output (MIMO) wireless communication system. The method includes exchanging information between terminals concerning the number of transmit antennas and number of receive antennas. In some embodiments antenna usage is based on the number of transmit antennas, the number of receive antennas, and an indication of channel quality. In some embodiments less than all of the available antennas, particularly transmit antennas, are used at a given time, with unused transmit antennas varying over time.

Abstract: Techniques and systems for design and use of generalized LDPC codes. A generalized LDPC code comprises a set of codewords producing valid results when submitted to a validator comprising a set of variable nodes and a set of check nodes, with outputs of the variable nodes being connected to inputs of the check nodes by interleaver edges. Each check node and variable node is in the form of a code, with the output of a node being valid if its inputs form a valid codeword. An extrinsic information transfer function (EXIT) chart is used to form a check node curve and a variable node curve is matched to the check node curve. The variable nodes are then constructed so as to provide the information transfer properties indicated by the variable node curve.

Abstract: A rate adaptation scheme for a wireless transmission system. An information message encoded at a mother rate code is punctured to achieve an adapted rate approximate a selected code rate. The adapted code rate is such that all of the bits transmitted by multi bit symbols, such as OFDM symbols, are used to transmit information of the information message. The use of zero pad bits, or pad bits which cannot provide information regarding entirety of the information message is thereby reduced.

Abstract: A modulation and coding scheme for a communication system is based on use of nonsystematic repeat-accumulate codes for encoding channel information for transmission, and for employing a combined detection and decoding arrangement to decode the coded channel information. The nonsystematic repeat-accumulate codes may be generated by an encoder at a transmitter and decoded by a composite detector/decoder arrangement at a receiver.