DM-RS symbols may be inserted in the beginning of a subframe, or in two parts of the subframe. In one aspect, a method, a computer-readable medium, and an apparatus for dynamically conveying DM-RS information are provided. The apparatus may be a base station. The apparatus may determine the number of DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols. The apparatus may transmit the number of the DM-RS symbols and/or the locations within the subframe for transmission of the DM-RS symbols to a UE. In another aspect, a UE may receive the number of DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols from a base station. The UE may decode the DM-RS symbols from the subframe based on the number of the DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols.

The present invention discloses a preamble sequence generating method and device, which are used to avoid a problem, caused by damages to a preamble sequence resulting from interference in an NB-PLC system, that it is difficult for a receive end to correctly perform timing synchronization. The method includes: determining a quantity m of orthogonal frequency division multiplexing OFDM symbols that constitute a single pattern in a preamble sequence, where m is not less than 2; and generating a preamble sequence according to m, so that every m OFDM symbols that are in the generated preamble sequence and consecutive in a time domain constitute a single pattern, and the generated preamble sequence includes at least two patterns, where the patterns are different from each other. Embodiments of the present invention further provide a timing synchronization method and device.

A transmission apparatus includes a data-block generating unit that generates and outputs a data block including fixed sequence symbols whose signal values are formed of a fixed sequence and data symbols, a pilot-block generating unit that generates and outputs a pilot block including the fixed sequence symbols and pilot symbols that are fixed symbols known on a reception side, and an output control unit to which the data block and the pilot block are inputted, which controls whether the data block or the pilot block is outputted.

In certain aspects, a circuit comprises a low noise amplifier (LNA) configured to receive a radio frequency (RF) signal, a first mixer coupled to the low noise amplifier (LNA), and a first trans-impedance filter coupled to the first mixer. The first trans-impedance filter comprises a tunable inductor and capacitor (LC) network configured to be a portion of a doubly terminated LC ladder filter and a trans-impedance amplifier (TIA) coupled to the tunable inductor and capacitor (LC) network. The circuit further comprises a second mixer coupled to the low noise amplifier (LNA) and a second trans-impedance filter coupled to the second mixer.

An exemplary embodiment of the present invention provides a pilot signal generating apparatus, including: a changed amount estimating unit which estimates a changed amount of a pilot symbol due to interference of a data symbol which is adjacent to a predefined position of the pilot symbol; and a symbol generating unit which generates the pilot symbol in consideration of the estimated changed amount.

Phase noise estimation and cancellation as disclosed herein may allow cost-efficient increase of capacity in communications by enabling very high QAM levels. The proposed solution is potentially applicable to any single carrier applications where phase noise is a limiting factor and a required order of modulation is very high. For example, disclosed embodiments may enable high QAM levels for microwave backhauls despite severe phase noise sensitivity. One embodiment involves a pilot-aided and BCJR-based sequential search algorithm that accurately estimates and subtracts fast-varying phase noise symbol-by-symbol. Residual BER performance is evaluated under the most challenging phase noise scenarios. FPGA emulation results show detection and removal of a significant amount of phase noise and zero BER performance even for complex 1K-QAM and above.

In some aspects, the disclosure is directed to methods and systems for receive-side distortion cancellation in orthogonal frequency division multiplexing (OFDM). Each of a plurality of OFDM receivers generates a distortion signal; modulates, amplifies, and demodulates the distortion signal; and then mixes a received signal with an inverse of the demodulated distortion signal, along with demodulated distortion signals provided by each other receiver. The resulting output signal may be de-mapped and decoded, with amplifier distortion reduced.

DM-RS symbols may be inserted in the beginning of a subframe, or in two parts of the subframe. In one aspect, a method, a computer-readable medium, and an apparatus for dynamically conveying DM-RS information are provided. The apparatus may be a base station. The apparatus may determine the number of DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols. The apparatus may transmit the number of the DM-RS symbols and/or the locations within the subframe for transmission of the DM-RS symbols to a UE. In another aspect, a UE may receive the number of DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols from a base station. The UE may decode the DM-RS symbols from the subframe based on the number of the DM-RS symbols and/or the locations within a subframe for transmission of the DM-RS symbols.

The present invention relates to an apparatus for obtaining a signal, which may comprise an electronic apparatus comprising: an antenna for receiving a signal via at least one channel from an external apparatus; a reference signal generation unit for generating a reference signal on the basis of frequency-related values and transmitting the reference signal to a signal correlation unit; a signal correlation unit for calculating a correlation value between the signal and the reference signal; a correlation maximum signal identifying unit for identifying a time value corresponding to a correlation value exceeding a preset reference value from among correlation values calculated from the signal correlation unit and delivering the identified time value to a least square calculation unit; and a least square calculation unit for calculating at least any one of a magnitude value and a phase value of a frequency on the basis of the identified time value and delivering the calculated value to the reference signal generation unit. However, the present invention is not limited to the above-described embodiment, but may include other embodiments.

A receiving node 202 and a method therein for estimating a time synchronization position m.sub.0 of a signal received from a transmitting node 204. The receiving node r.sub.1.sup.w receives a first signal from the transmitting node, wherein the first signal comprises a first training signal t.sub.1.sup.n. The first training signal is known to the receiving and transmitting nodes. The receiving node performs a non-linear transformation of the first signal r.sub.1.sup.w resulting in a first non-linearly transformed signal r,r, and a non-linear transformation of the first training signal resulting in a second non-linearly transformed signal t,t. Further, the receiving node performs a cross-correlation of the first non-linearly transformed signal and the second non-linearly transformed signal. The receiving node estimates the time synchronization position of the first signal based on the cross-correlation.