Abstract: Systems (100) and methods (700) for processing a data signal in a communications system. The methods involve generating a first chaotic sequence at a transmitter (102). The methods also involve performing first basis function algorithms using the first chaotic sequence to generate first statistically orthogonal chaotic sequences. At least one sequence is selected from the first statistically orthogonal chaotic sequences for combining with a first data signal. The selected sequence is combined with a second data signal to obtain a modulated chaotic communication signal. The modulated chaotic communication signal is transmitted to a receiver (104). At the receiver, the received modulated chaotic communication signal is processed to obtain data therefrom. Notably, the signal processing generally involves performing a deterministic process (e.g., a Hidden Markov Model deterministic process).

Abstract: A system and apparatus are disclosed for a method and apparatus for equalizing signals. An apparatus that incorporates teachings of the present disclosure may include, for example, an equalizer (100) having a channel estimation calculator (102) for calculating a time domain channel estimation from a baseband signal, an FFT processor (104) for translating the time domain channel estimation to a frequency domain channel estimation, a tap weight calculator (106) for calculating a frequency domain tap weight according to the frequency domain channel estimation, an inverse FFT processor (108) for translating the frequency domain tap weight calculation to a time domain tap weight calculation, and a filter (110) for equalizing the baseband signal according to the time domain tap weight calculation.

Abstract: A signal reception apparatus of an orthogonal frequency division multiplexing (OFDM) communication system using a multiple input, multiple output (MIMO) scheme. The signal reception apparatus, when it uses the NR receive antennas, receives a time-domain preamble signal transmitted by a signal transmission apparatus corresponding thereto via each of the NR receive antennas, and estimates a channel according to a channel estimation scheme using the time-domain preamble signal received via each of the NR receive antennas. When the signal transmission apparatus uses NT transmit antennas, the time-domain preamble signal is a signal transmitted by the signal transmission apparatus via each of the NT transmit antennas for a second time period which is set according to a corresponding transmit antenna within a first time period.

Abstract: Disclosed are a radio transmission device and a radio transmission method which can reduce a processing amount or a memory amount while maintaining the randomizing effect of other cell interference. When using as a reference signal, a ZC sequence of the sequence length uniquely correlated to a transmission bandwidth of a reference signal, as the transmission bandwidth becomes smaller and the sequence length of the ZC sequence becomes shorter, the sequence is switched at a shorter time interval and as the transmission bandwidth becomes greater and the sequence length of the ZC sequence becomes longer, the switching is performed at a longer time interval. Thus, a reference signal is generated by using the ZC sequence in accordance with the timing into which the reference signal transmission bandwidth and the sequence are switched.

Abstract: A decoder and related method adaptively generate a clock window. A falling edge of a horizontal synchronization signal is detected, and the time difference between an actual frame code and a predefined frame code is determined. The beginning and the end of the clock window are then adaptively determined based on the falling edge and the time difference, such that symbol timing recovery through received clock run-in signals may be performed within the generated clock window.

Abstract: A synchronization method in a Ultra Wideband (UWB) receiver includes receiving a signal through a multipath channel, and synchronizing with a first multipath component of the received signal by computing a correlation value between the received signal and a template signal of the receiver in a predetermined search range. Since multipath components received at the receiver after the first multipath component of the received signal have lower power than that of the first multipath component, the synchronization with the first multipath component of the received signal may improve the performance in processes after the synchronization process.

Abstract: There is provided a wireless communication method, a wireless communication system, a base station and a mobile station which conduct wireless communication using an OFDM modulation scheme. The base station transmits a timing correction burst to the mobile station only when a correlation peak detected from a received OFDM symbol is within a predetermined timing detection range. If the timing correction burst is not introduced from the base station even after expiration of predetermined time duration, by copying a signal by a length different from a guard interval from the end of an effective symbol and adding the copied signal to the front of the effective symbol, the mobile station generates a new timing correction channel (second time), in which transmission timing of a previously generated timing correction channel is shifted.

Abstract: An information processing device is provided that includes a signal receiving portion, an absolute value conversion portion, and an input data decoding portion. The signal receiving portion receives a signal that is encoded such that mutually distinct first and second bit values are respectively expressed by pluralities of mutually distinct first amplitude values and second amplitude values, the first and second bit values also being encoded such that the same amplitude value does not occur twice in succession and such that the polarities of the amplitude values are inverted with each cycle. The absolute value conversion portion converts into absolute values the amplitude values of the signal that has been received by the signal receiving portion. The input data decoding portion decodes the first and second bit values based on the amplitude values in the signal that have been converted into absolute values by the absolute value conversion portion.

Abstract: In one aspect, the present invention greatly simplifies soft modulation calculations, in part by exploiting certain properties of Gray-mapped QAM constellations used in modulating symbols of interest. In at least one embodiment, the simplified processing includes performing the soft modulation separately for the real and imaginary parts of each symbol of interest, by using the Gray mapping to decompose each of the real and imaginary parts into binary soft modulations for each bit, and then using a computationally-efficient table lookup to calculate the binary soft modulation. Here, the look-up table comprises pre-computed bit contributions to the complex soft symbol value to be formed for the symbol of interest.

Abstract: The method includes an interference deduction mode for reducing interferences between a wideband device and a narrowband device. The method is performed within the wideband device and includes detecting an emission from and/or a reception performed by the narrowband device; determining from the detection step a group of at least one sub-carrier having frequencies interfering with the narrowband devices; and frequency shifting at least a part of frequency band of the wideband device including the group of at least one interfering sub-carriers with a chosen frequency shift such that at least a part of frequency band of the narrowband device is excluded from the frequency band of the wideband device.

Abstract: A MIMO transmitter has a modulator (40,41,42, 120, 122) a demultiplexer 100 arranged to divide the information into one or more demux streams for transmission over different ones of the channels, and a diversity splitter (110) to derive one or more sub-streams of the same information. A decorrelator (120) such as a scrambler (150, 155) decorrelates the sub-streams before or after the modulation. The arrangement is configurable to vary in use a ratio of demultiplexing and of diversity splitting. This balances between the gains from diversity and spatial multiplexing, without needing major changes to the transmit and receive processing.

Abstract: A method and apparatus for estimating a frequency response of a channel. The method includes adjusting phase components of estimates of the frequency response to provide phase-adjusted estimates; performing a smoothing operation on the phase-adjusted estimates to provide smoothed phase-adjusted estimates; and generating an output of a reverse phase adjustment, wherein the reverse phase adjustment is performed on the smoothed phase-adjusted estimates.

Abstract: Systems and methods for detecting data in a multiple input/multiple output signal. The method includes receiving a first signal associated with a first data value and a second signal associated with a second data value. A distance value between the received second signal and each possible second data value is calculated. Coordinates for a hypothetical first signal in light of a first possible second data value are calculated, and the first coordinate value is quantized to a nearest constellation point. A distance value between the received second signal and each possible second data value is calculated using the calculated constellation points. A determination is made of a log-likelihood ratio based on the determined distance values.

Abstract: A method and system adaptively reduce a peak-to-average power ratio in a communication system. Energy is clipped from at least one peak of a modulated signal. The modulated signal includes a plurality of sub-carriers. At least one data sub-carrier is adaptively selected for peak-to-average power ratio reduction use based on known scheduling information. The clipped energy is distributed among at least one data sub-carrier.

Abstract: Particular codebook entries used for a MIMO system of a lower dimension (i.e., having a relatively low number of antennas) can be used to generate a codebook for a MIMO system of a higher dimension (i.e., having a relatively high number of antennas). The entries in rank 1 of the codebook related to the MIMO system having four transmit antennas are used to newly construct entries for rank 1 through rank 8 of two base matrices for a MIMO base codebook related to eight transmit antennas.

Abstract: The present invention efficiently stores a training sequence in a communications system, where the training sequence exhibits certain desirable characteristics when used by a peak to average power constrained modulation format.

Abstract: Disclosed is an apparatus including an odd data receiving unit that receives an input signal, an even data receiving unit that also receives the input signal, and a pattern filter. The odd data receiving unit samples a half-rate DFE equalized signal with an odd data timing clock to output data decision data. The even data receiving unit samples the half-rate DFE equalized signal with an even data timing clock having the phase shifted by 180 degrees from the odd data timing clock to output data decision data. The pattern filter selects one of the edge decision data sampled at the odd edge timing and at the even edge timing in response to the value of a data pattern of three consecutive bits obtained from the data decision data sampled at the odd and even data timings.

Abstract: The present invention employs hierarchical modulation to simultaneously transmit information on different modulation layers using a carrier RF signal. Initially, first data to be transmitted is assigned to a first modulation layer and second data is assigned to a second modulation layer. In one embodiment of the present invention, the first and second data are assigned based on reliability criteria. The first and second modulation layers are hierarchical modulation layers of the carrier RF signal. Once assigned, the first data is transmitted using the first modulation layer of the carrier RF signal and the second data is transmitted using the second modulation layer of the carrier RF signal. In one embodiment of the present invention, information may be transmitted to one end user using one modulation layer, and information may be transmitted to a different end user using a different modulation layer.

Abstract: Embodiments of the present invention relate to a system for clock synthesis or data timing recovery. No analog continuous time oscillator is required, all the building blocks of a Frequency Locked Loop/Phase Locked Loop belonging in the digital discrete time domain. From a system-level perspective, the system is characterized by its strong non-linear behavior due to the intrinsic nature of some building blocks. This inherent non-linearity is responsible for some unusual, attractive property of the complete system. The system is able to multiply the input frequency clock by an arbitrarily large factor, ensuring in any case the convergence of the algorithm in two reference clock cycles.

Abstract: There is already disclosed a technique for an MB-OFDM communication system whereby an orthogonal demodulation section removes a DC offset generated in a received signal in a region where the received signal is an analog signal, but the removal of the DC offset in the analog region cannot prevent the DC offset from remaining, and therefore the DC offset needs to be effectively removed in a digital region. An offset canceling section 26 calculates an average value of amplitude of a signal which should have an average of amplitude within a predetermined time range of 0, subtracts the average value from the signal and thereby removes an offset included in the signal.