Abstract: A method for performing a multi-stage dilation of optical fibers is described, the method comprising performing successive dilation steps such that the adiabatic condition is maintained throughout the fiber. There is also described various optical devices employing such multi-stage dilated optical fibers, as well as methods of manufacture of the optical devices.

Abstract: A method for transmitting data in a wireless communication system provides transmitting a cluster allocation message, which informs at least one user equipment that the user equipment belongs to a cluster, to the at least one user equipment, and receiving a response to the cluster allocation message from user equipments belonging to the cluster. Small envelope correlation coefficient can be obtained without increasing the size of a user equipment.

Abstract: A method for performing a multi-stage dilation of optical fibres is described, the method comprising performing successive dilation steps such that the adiabatic condition is maintained throughout the fibre. There is also described various optical devices employing such multi-stage dilated optical fibres, as well as methods of manufacture of the optical devices.

Abstract: A radio frequency (RF) signal transmission/reception apparatus and an RF signal transmission/reception method are disclosed. The RF signal transmission/reception apparatus is adapted to perform a transmission/reception duplex function using a bi-directional mixer at the IF band or baseband, not at the RF band. When a reception signal of the RF band is passed through the bi-directional mixer, it is converted into a signal in any one of the IF band and the baseband. Also, when a transmission signal in any one of the IF band and the baseband is passed through the bi-directional mixer, it is converted into a signal of the RF band.

Abstract: The invention provides simultaneous suppression of PMD and PDG in a fiber Raman amplifier. One embodiment employs a two-section fiber with one section being unspun and the other, longer, section having a periodic spin profile. The other embodiment employs a single segment fiber having a periodic exponentially varying spin profile.

Abstract: A radio frequency (RF) signal transmission/reception apparatus and an RF signal transmission/reception method are disclosed. The RF signal transmission/reception apparatus is adapted to perform a transmission/reception duplex function using a bi-directional mixer at the IF band or baseband, not at the RF band. When a reception signal of the RF band is passed through the bi-directional mixer, it is converted into a signal in any one of the IF band and the baseband. Also, when a transmission signal in any one of the IF band and the baseband is passed through the bi-directional mixer, it is converted into a signal of the RF band.

Abstract: A quasi-parallel receiver may simultaneously receive signals within several subchannels that comprise a wideband channel. The receiver includes a subchannel filter selection switch that provides a baseband signal to a selected one of a plurality of subchannel low-pass filters. A heterodyne frequency generator provides one of a plurality of heterodyne frequencies to convert an RF signal received within a selected subchannel to the baseband signal. The subchannel low-pass filters accumulate signal information from an associated one of a plurality of subchannels during a filter-input sampling interval. In some embodiments, individual analog-to-digital converters receive the accumulated signal outputs from an associated subchannel filter and generate digital signals for a subsequent Fourier transformation. In some embodiments, a normalized signal output may be provided to the analog-to-digital converters, allowing the use of lower resolution analog-to-digital converters.

Abstract: A reconfigurable multichannel receiver may selectively operate in increased throughput modes and/or increased range modes. In some embodiments, the receiver may select two or more antennas from a plurality of spatially diverse antennas to receive more than one subchannel of a wideband orthogonal frequency division multiplexed (OFDM) channel. Maximum-ratio combining may be performed on corresponding symbol-modulated subcarriers from the two or more antennas, and a single OFDM symbol may be generated from contributions from the subchannels received by the two or more antennas. In other embodiments, more than one subchannel of a wideband OFDM channel may be received through a single antenna selected from a plurality of spatially diverse antennas. In other embodiments, a single subchannel may be received by a plurality of spatially diverse antennas and maximum-ratio combining may be performed on corresponding symbol-modulated subcarriers received by the antennas.