Abstract: Methods, apparatus and systems for measuring signal transition times for a four-level pulse modulated amplitude (PAM4) transmitter. During a test procedure, a PAM4 transmitter is configured to repetitively transmit a PAM4 symbol test pattern, which is captured as a signal waveform. The test pattern includes at least one rising signal sequence having a PAM4 symbol pattern of at least three ?1 PAM4 symbols followed by at least three +1 PAM4 symbols and at least one falling signal sequence having a PAM4 symbol pattern of at least three +1 PAM4 symbols followed by at least three ?1 PAM4 symbols. A voltage modulation amplitude (VMA) level for each of a ?1 and +1 PAM4 signal level is measured for at least one rising signal sequence and falling signal sequence to derive 20% and 80% VMA levels.

Abstract: A transmission device that performs multiple-input multiple-output (MIMO) transmission of transmit data using a plurality of fundamental bands. The transmission device includes an error correction coding unit, a mapping unit, and a MIMO coding unit. The error correction coding unit, for each data block of predefined length, performs error correction coding and thereby generates an error correction coded frame. The mapping unit maps each predefined number of bits in the error correction coded frame to a corresponding symbol and thereby generates an error correction coded block. The MIMO coding unit performs MIMO coding with respect to the error correction coded block. Components of data included in the error correction coded block are allocated to at least two of the fundamental bands and transmitted.

Abstract: An apparatus comprising a first loss of signal circuit, a second loss of a signal circuit and a gate circuit. The first loss of a signal circuit may be configured to (i) receive an input signal containing a series of data and (ii) generate a first indication signal when the input signal is operating within a first frequency range. The second loss of signal circuit may be configured to (i) receive the input signal and (ii) generate a second indication signal when the input signal is operating within a second frequency range. The gate circuit may be configured to generate an output signal in response to either the first indication signal or the second indication signal being active.

Abstract: During transmission of a signal, a decoder receives a data symbol sequence and one or more copies of the data symbol sequence. The data symbol sequence and each of the copies have unknown noise, including unknown phase shifts. The unknown phase shifts are estimated such that the data symbol sequence that was transmitted is substantially recovered.

Abstract: The invention relates to transmission and reception of clock synchronization data in a wireless communication system. According to the invention a device for transmitting clock synchronization data obtains at least one time reference of a wireless communication system clock, controls transmission of a frequency reference of the wireless communication system clock via an air interface of the wireless communication system, and provides transmission of the time reference via a transport network associated with the wireless communication system, while the base station receives the frequency reference, locks an own oscillator to the frequency of the frequency reference, receives the time reference from the transport network and adjusts timing that is controlled by the oscillator based on the time reference.

Abstract: Methods and apparatus for automatic gain control (AGC) and DC calibration for orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) systems are provided in an effort to avoid saturation of the analog-to-digital converter (ADC) in a radio frequency (RF) front end of a receiver, to handle dynamic received signal power, or to avoid interruptions in a communication link for DC calibration. For certain embodiments, the quantization error in the RF front end may also be decreased.

Abstract: A SerDes corn link with a retiming receiver is operable in link training (LT) mode. A SerDes transmitter includes a TX FIR channel driver to transmit TX Data with TX pre-emphasis EQ based on TX FIR coefficients. The retiming receiver includes an RTE (retimer/reclocker) with an RT FIR driver outputting retimed RX Data based on RT FIR coefficients. A link training unit (LTU) adjusts RT FIR coefficients based on a comparison of impulse cursor information for RX Data signals received at the RTE input and re-timed RX Data signals output from the RT FIR, so that the adjusted RT FIR coefficients correspond to the TX FIR coefficients (including reflecting LT changes in TX pre-emphasis EQ). In effect, the LTU performs a linear FIR coefficient translation from the TX FIR to the RT FIR, propagating LT FIR coefficient changes from RTE input to output.

Abstract: Methods and apparatus are provided for implementing a digital host-lock mode in a transceiver. The transmitter portion of a transceiver is synchronized to a recovered clock generated by the receiver portion of the transceiver by applying a receiver input signal to a clock and data recovery system in the receiver portion to generate the recovered clock and a frequency offset value. The frequency offset value comprises a digital word indicating a frequency offset between the recovered clock and the receiver input signal. A transmit clock is generated in the transmitter portion that is substantially synchronized to the recovered clock by applying the digital word to a clock signal generator.

Abstract: A method for determining signal phase rotation of sub-channels within a contiguous transmission bandwidth comprises the steps of: determining a fundamental set of phase rotations; performing a cyclic shift operation for the fundamental set of phase rotations to generate a cyclic-shifted set of phase rotations; multiplying the cyclic-shifted set of phase rotations by a complex constant to generate a final set of phase rotations; and determining the phase rotation of each sub-channel within the contiguous transmission bandwidth according to the final set of phase rotations.

Abstract: A system and method for channel interleaver and layer mapping in a communications system with spatial multiplexing are provided. A method for transmitting information over M layers, where M is a positive integer value representing a number of spatial layers, and M?2, includes receiving at least one codeword to transmit, grouping a plurality of symbols in the at least one codeword into M groups, mapping the M groups to the M layers, and transmitting the M layers. The at least one codeword includes the plurality of symbols, and each symbol includes two or more code bits.

Abstract: A broadband powerline communication system makes use of knowledge of the spectrum characteristics of a local radio environment in order to improve system performance. A determination is made of the spectrum characteristics of a radio environment in the vicinity of the broadband powerline communication system that is transmitting data on modulated carrier frequencies. In order to avoid interference, certain ones of the carrier frequencies otherwise used by the broadband powerline communication system may be selectively masked based on the determination. The spectrum characteristics may be determined 1) in advance and used to compile a configuration database comprising frequency masking parameters; 2) by monitoring the local radio environment using the transmitter/receiver nodes of the system; or 3) based upon receipt of an indication from a conflicting user that the user is experiencing interference. Various combinations of these spectrum characteristic determination techniques may also be used.

Abstract: Systems and methods are provided for decoding a signal vector in a transmit diversity scheme for varying channels. Information obtained in more than one symbol period are treated as a single received vector, and each of the received signal vectors may be processed to reduce the effects of varying channel characteristics. The received signal vectors may be combined by addition and decoded using a maximum-likelihood decoder. In some embodiments, the received signal vectors are processed separately and then combined. In other embodiments, the received signal vectors are combined and then processed. In some embodiments, zero-forced linear equalization techniques are used to processed the received signals. In some embodiments the signal vectors and varying channel response matrices are broken down to equivalent forms in order to simplify the processing.

Abstract: A wireless communication device is disclosed. The wireless communication device includes a frequency hopping communication circuit, a power spectral density circuit and a control circuit. The frequency hopping communication circuit includes a channel map. The frequency hopping communication circuit selects one of channel in a channel map to connect to another frequency hopping communication circuit according to the channel map. The power spectral density circuit for generating a power spectral density signal by measuring spectrums on all channels connected to the frequency hopping communication circuit. The control circuit receives the power spectral density and output statistical distribution data to the frequency hopping communication circuit. The frequency hopping communication circuit updates the channel map according to the statistical distribution data.

Abstract: A method of transmitting data using hybrid automatic repeat request (HARQ) is provided. The method includes transmitting an initial data, receiving a retransmission request for the initial data, generating a retransmission data by shifting the phase of the initial data on signal constellation and transmitting the retransmission data. Inter-cell interference or intra-cell interference can be mitigated.

Abstract: Described herein are an apparatus, system, and method for generating pulse modulated (PWM) signals. The apparatus (e.g., input-output transmitter) comprises: an edge detector to detect one of a rising or falling edges of a clock signal; a counter to count up or down in response to detecting one of the rising or falling edges of the clock signal, the counter to generate a select signal; and a control unit to receive a data signal for transmission to a receiver and to generate a PWM signal as output according to a value of the select signal and the data signal, wherein the receiver and the transmitter are a Mobile Industry Processor Interface (MIPI®) M-PHYSM receiver and transmitter.

Abstract: Systems and methods are disclosed for receivers of transmit chains of a MIMO system to receive transmit power information and to compute channel characteristics of the transmit chains to enable dynamic adjustment of the transmit power on the transmit chain to optimize an overall data throughput while meeting a maximum emission limit, such as a regulatory limit on emitted power. The transmit power and the data rate on the transmit chains may be independently controlled. The receiver of the MIMO system may determine the new transmit power for the transmit chains from the computed channel characteristics and the current transmit power of the transmit chains. Alternatively, the receiver may transmit the computed channel characteristics of the transmit chains to the transmitter for the transmitter to determine the new transmit power for the transmit chains. The transmitter may use the new transmit power to transmit new data on the transmit chains.

Abstract: A method for symbol synchronization of received digital signal and a digital signal reception apparatus are provided. The method comprises steps of correlating the received digital signal with the received signal delayed by one symbol so as to obtain a first correlation value result as a combined effort of a strongest path and other paths; removing substantially effect of the strongest path from the first correlation result so as to obtain a second correlation result which exhibits contribution of a fastest path; searching a maximum correlation value and its position of the fastest path so as to determine symbol synchronization timing for initiating FFT processing. The digital signal reception apparatus is characterized by a symbol timing detecting unit for determining symbol synchronization timing of the fastest path through substantially removing the effect of a strongest path.

Abstract: Methods and systems are disclosed for frequency-domain frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency domain components associated with subcarriers within the multi-carrier communication signals. A sliding-window correlation (e.g., two-dimensional sliding window) is applied to the received symbols represented in the frequency domain to detect frame boundaries for multi-carrier signals. The sliding-window frame synchronization can be applied by itself or can be applied in combination with one or more additional frame synchronization stages. The disclosed embodiments are particularly useful for frame synchronization of multi-carrier signals in PLC (power line communication) systems.

Abstract: A soft impact location system and method which detects and processes wide-band acoustic signatures for testing long-range munitions. The system incorporates a real-time digital signal-processing algorithm that detects the impact signature, processes it, and calculates the time-of-arrival (TOA). The system comprises a polyphase filter bank, boxcar filter, a detection analyzer for detecting an impact, and time-tagging software for calculating the time of impact. The system splits the received hydrophone signal into evenly spaced energy bands, processes each band individually, and then recombines the data to provide a precise time of detection.

Abstract: Methods and systems are disclosed for frequency-domain amplitude normalization for symbol correlation in multi-carrier communication systems. Digital samples associated with input signals received from a communication medium are processed using a Fast Fourier Transform (FFT) to generate complex frequency components. Each complex frequency component is normalized with respect to its amplitude, and the frequency-domain, amplitude-normalized frequency components are multiplied with frequency components for reference symbol(s) to generate frequency-domain correlation values. These frequency-domain correlation values are analyzed to determine if a correlation exists between the amplitude-normalized frequency components and the predetermined reference frequency components. A correlation detection output is then generated that indicates whether or not a symbol synchronization was achieved.