Abstract: Cathodes and lithium secondary batteries including the cathodes are disclosed. In some implementations, a cathode may include a cathode current collector and a cathode active material layer disposed on the cathode current collector and including cathode active material particles such that the cathode active material layer satisfies a specific equation. The cathode active material particles may include lithium metal oxide particles that include nickel, and may have a mole fraction of cobalt of 0.02 or less with respect to all elements except for lithium and oxygen.

Abstract: A battery pressure measuring sensor according to an embodiment of the present disclosure includes a substrate; a plurality of variable resistor units provided at a plurality of locations in consideration of a swelling characteristic of a battery on the substrate and configured to change a resistance value within a corresponding resistance range according to a pressure applied to each unit; and a plurality of sensing lines configured to be connected to the plurality of variable resistor units, respectively.

Abstract: A cathode for a lithium secondary battery includes a cathode current collector, and a cathode active material layer formed on the cathode current collector. The cathode active material layer includes cathode active material particles. The cathode active material particles include a lithium metal oxide particle containing nickel and having a mole fraction of cobalt of 0.02 or less among all elements except lithium and oxygen.

Abstract: A method and apparatus of transmitting a reference signal in a wireless communication system is provided. A reference signal sequence is generated by using a pseudo-random sequence. A portion or entirety of the reference signal sequence is mapped to at least one resource block and is transmitted. The pseudo-random sequence is generated by a gold sequence generator which is initialized with initial values obtained by using cell identifier. The reference signal provides low PAPR and high cross correlation characteristic.

Abstract: Provided is a transmission data frame in an orthogonal frequency division multiplexing (OFDM) burst mode transmission, and more particularly, a frequency offset estimating method and a channel equalizing method using a transmission data frame. In the transmission data frame used in the orthogonal frequency division multiplexing burst mode transmission, a length of a guard interval in a preamble area for frequency offset estimation and channel estimation varies depending on a channel environment not being limited in consideration of a size of a data symbol, and only data of ending part of the guard interval in the preamble is used to estimate frequency offset in consideration of intersymbol interference. In the frequency offset estimating method, desired frequency estimation efficiency can be satisfied with the small number of samples. Also, when channel equalization is performed, two symbols are averaged in a time area to reduce the accuracy of channel estimation due to Gaussian random noise.

Abstract: Disclosed is a method for compensating for a residual frequency offset in an orthogonal frequency division multiplexing system comprising the steps of: a) performing a fast fourier transform for an input signal to convert the input signal into a serial signal; b) detecting signal power of the serial signal to control the passthrough a signal greater than a predetermined critical value; c) selecting each section of a quadrant for each passed signal; d) estimating a phase error in each section of the quadrant for one orthogonal frequency division multiplexing symbol with respect to the selected section of the quadrant; and e) frequency-oscillating a signal based on the estimated phase error, generating the input signal by multiplying an oscillated signal by a band-passed signal, and then returning to step a).

Abstract: An approximation method and system for series expansion of functions include the steps and functions, respectively, of: expanding an input function in Taylor series up to an (N?1)-th term; expanding the input function in Taylor series up to the N-th term; multiplying the expanded result up to the (N?1)-th term by a predetermined weight ?; combining the expanded result up to the (N?1)-th term, multiplied by ?, and the expanded result up to the N-th term; and dividing the combined result by (?+1).

Abstract: Provided is a frame synchronization pattern design and synchronization method by which in a transmitter of a communications system employing an orthogonal frequency division multiplexing (OFDM), a frame synchronization pattern is inserted into the starting part of a symbol frame, and by detecting the frame synchronization pattern in a receiver, synchronization of the OFDM transmitter and receiver is performed. Also, provided are a transmitter synchronization apparatus including an OFDM symbol frame generation unit, a frame synchronization pattern insertion unit, and an OFDM transmission signal conversion unit, and a receiver synchronization apparatus comprising a frame synchronization pattern inserted OFDM symbol frame conversion unit, a frame synchronization pattern detection unit, and a source data generation unit.

Abstract: Disclosed is a method for compensating for a residual frequency offset in an orthogonal frequency division multiplexing system comprising the steps of: a) performing a fast fourier transform for an input signal to convert the input signal into a serial signal; b) detecting signal power of the serial signal to control the passthrough a signal greater than a predetermined critical value; c) selecting each section of a quadrant for each passed signal; d) estimating a phase error in each section of the quadrant for one orthogonal frequency division multiplexing symbol with respect to the selected section of the quadrant; and e) frequency-oscillating a signal based on the estimated phase error, generating the input signal by multiplying an oscillated signal by a band-passed signal, and then returning to step a).

Abstract: An approximation method and system for series expansion of functions include the steps and functions, respectively, of: expanding an input function in Taylor series up to an (N−1)-th term; expanding the input function in Taylor series up to the N-th term; multiplying the expanded result up to the (N−1)-th term by a predetermined weight &agr;; combining the expanded result up to the (N−1)-th term, multiplied by &agr;, and the expanded result up to the N-th term; and dividing the combined result by (&agr;+1).

Abstract: Provided is a transmission data frame in an orthogonal frequency division multiplexing (OFDM) burst mode transmission, and more particularly, a frequency offset estimating method and a channel equalizing method using a transmission data frame. In the transmission data frame used in the orthogonal frequency division multiplexing burst mode transmission, a length of a guard interval in a preamble area for frequency offset estimation and channel estimation varies depending on a channel environment not being limited in consideration of a size of a data symbol, and only data of ending part of the guard interval in the preamble is used to estimate frequency offset in consideration of intersymbol interference. In the frequency offset estimating method, desired frequency estimation efficiency can be satisfied with the small number of samples. Also, when channel equalization is performed, two symbols are averaged in a time area to reduce the accuracy of channel estimation due to Gaussian random noise.

Abstract: Provided is a frame synchronization pattern design and synchronization method by which in a transmitter of a communications system employing an orthogonal frequency division multiplexing (OFDM), a frame synchronization pattern is inserted into the starting part of a symbol frame, and by detecting the frame synchronization pattern in a receiver, synchronization of the OFDM transmitter and receiver is performed. Also, provided are a transmitter synchronization apparatus including an OFDM symbol frame generation unit, a frame synchronization pattern insertion unit, and an OFDM transmission signal conversion unit, and a receiver synchronization apparatus comprising a frame synchronization pattern inserted OFDM symbol frame conversion unit, a frame synchronization pattern detection unit, and a source data generation unit.