Abstract: An efficient system and method for modulation and demodulation to achieve a high data rate using Bit-Interleaved Coded Modulation and OFDM uses either a coherent or a non-coherent transmission scheme using differential modulation. In order to maintain a high data rate impervious to sudden phase changes, a communication system uses an efficient constellation having multiple rings with different sizes and modulation/demodulation schemes utilizing this constellation. In power line communications, the channel gain information is obtained easily at a receiver (100) while the phase information is not. Thus, the communication system uses an absolute magnitude and differential phase coding for modulation and demodulation of the signals.

Abstract: A semiconductor device having resistors in a peripheral area and fabrication method thereof are provided. A mold layer is formed on a semiconductor substrate. The mold layer is patterned to form first molding holes and a second molding hole in the mold layer. A storage node layer is formed on the mold layer as well as in the first and second molding holes. The storage node layer is patterned to form storage nodes in the first molding holes and a portion of a resistor in the second hole.

Abstract: A method for managing scanning of a plurality of channels in a wireless network is disclosed. The method comprises detecting by a station that a first channel in a plurality of channels is being used for a communication by another station, determining a duration of the communication based upon the communication information, setting a Network Allocation Vector for the station based on the determined duration, scanning a number of channels during the determined duration, and returning to the first channel upon at least one of a) completion of the step of scanning and b) an end of the determined duration.

Abstract: A phase-changeable memory device may include a substrate including a peripheral region and a cell region, a first pad on the peripheral region, a second pad on the cell region, a lower electrode on the second pad, an insulation layer pattern on the substrate, the insulation layer pattern including a first opening exposing the lower electrode and a second opening exposing the first pad, a phase-changeable layer pattern including a phase-changeable material and being in the first opening, a metal plug in the second opening, the metal plug having an upper surface higher than that of an upper surface of the phase-changeable layer pattern, an upper electrode formed on the phase-changeable layer pattern, and a conductive wiring formed on the metal plug.

Abstract: In a semiconductor memory device and method, phase-change memory cells are provided, each including a plurality of control transistors formed on different layers and variable resistance devices formed of a phase-change material. Each phase-change memory cell includes a plurality of control transistors formed on different layers, and a variable resistance device formed of a phase-change material. In one example, the number of the control transistors is two. The semiconductor memory device includes a global bit line; a plurality of local bit lines connected to or disconnected from the global bit line via local bit line selection circuits which correspond to the local bit lines, respectively; and a plurality of phase-change memory cell groups storing data while being connected to the local bit lines, respectively.

Abstract: A preamble for an OFDM signal synchronizes (104) and estimates (106) the sub-channels with only one code. One polyphase code sequence is used repeatedly for the preamble. The preamble is spread out over the bandwidth, which is the same as an OFDM symbol in the frequency domain and has good autocorrelation characteristics in the time domain. All OFDM signals are added with this preamble at the beginning of the OFDM signal and transmitted on the channel at a transmitter (50). At the receiving end, the receiver (100) first does the autocorrelation process to find out a peak value for synchronization in the time domain. Then, since the polyphase code is known at the receiver, the signal to noise ratio for each sub-carrier is calculated in the frequency domain and smoothed using the normal (Gaussian) distribution to provide the channel estimation. Since the synchronization and channel estimation are processed with a single preamble, the overhead for these two functions is significantly reduced.

Abstract: An efficient system and method for modulation and demodulation to achieve a high data rate using Bit-Interleaved Coded Modulation and OFDM uses either a coherent or a non-coherent transmission scheme using differential modulation. In order to maintain a high data rate impervious to sudden phase changes, a communication system uses an efficient constellation having multiple rings with different sizes and modulation/demodulation schemes utilizing this constellation. In power line communications, the channel gain information is obtained easily at a receiver (100) while the phase information is not. Thus, the communication system uses an absolute magnitude and differential phase coding for modulation and demodulation of the signals.

Abstract: A semiconductor device having resistors in a peripheral area and fabrication method thereof are provided. A mold layer is formed on a semiconductor substrate. The mold layer is patterned to form first molding holes and a second molding hole in the mold layer. A storage node layer is formed on the mold layer as well as in the first and second molding holes. The storage node layer is patterned to form storage nodes in the first molding holes and a portion of a resistor in the second hole.

Abstract: A method of fabricating a semiconductor device having a cell array area and a peripheral circuit area is provided. A mold layer is formed on a substrate in the cell array area and the peripheral circuit area. A plurality of first molding holes are formed in the mold layer in the cell array area. A second molding hole is formed in the mold layer in the peripheral circuit area. A storage node layer is formed on the mold layer, in the first molding holes and in the second molding hole. A plurality of storage nodes are formed in the first molding holes and a first portion of a resistor is formed in the second molding hole by removing a portion of the storage node layer. The first portion of the resistor is formed of the storage node layer.

Abstract: A semiconductor device having resistors in a peripheral area and fabrication method thereof are provided. A mold layer is formed on a semiconductor substrate. The mold layer is patterned to form first molding holes and a second molding hole in the mold layer. A storage node layer is formed on the mold layer as well as in the first and second molding holes. The storage node layer is patterned to form storage nodes in the first molding holes and a portion of a resistor in the second hole.