摘要:
Provided is a crystalline form E of ertapenem sodium. Further provided is a method for preparing a crystalline form E of ertapenem sodium, characterized by using an aqueous ertapenem sodium solution at a low concentration as a raw material. The crystalline form E can be easily filtered and dried, the properties in the drying process are stable, and the purity of the crystal is high and can be up to 98.5% or higher.
摘要:
Provided is a crystalline form E of ertapenem sodium. Further provided is a method for preparing a crystalline form E of ertapenem sodium, characterized by using an aqueous ertapenem sodium solution at a low concentration as a raw material. The crystalline form E can be easily filtered and dried, the properties in the drying process are stable, and the purity of the crystal is high and can be up to 98.5% or higher.
摘要:
A system and method of DFT-S-OFDM modulation is provided that uses a set of frequency domain patterns. For a given transmitter, for a set of DFT-S-OFDM symbols, the frequency domain pattern changes according to a time domain hopping pattern. Advantageously, the time domain hopping patterns are defined to allow only a certain amount of overlap, for example for only one DFT-S-OFDM symbol, between any two time domain hopping patterns. This functions to reduce the effect of a collision, when two transmitters use the same frequency pattern, they will do so only for part of the overall transmission. Optionally, frequency domain spectral spreading is used in the transmitter. This can further reduce the PAPR. In the receiver, successive interference cancellation may be employed to reduce the effect of colliding transmissions.
摘要:
Embodiments of the invention provide orthogonal Frequency Division Multiplexing-Space-time Block Codes (OFDMSTBC) mappings for code rate 1, 2 and 4 codes for 4 Transmit Antennas. To overcome the innate weakness of known codes, a new class of STBC codes is provided which is particularly suited for OFDM applications, although other applications are also contemplated. Codes for STBC mappings in the time direction, the frequency direction and a combined time frequency mapping for multiple antennas are provided. In OFDM applications, these codes exploit the properties of OFDM and FEC codes to substantially maintain the advantages of Alamouti codes. Furthermore, while the detailed examples given herein focus on four antenna applications, they can be easily extended to systems with more than four antennas.
摘要:
An apparatus and method for transmitting data with conditional zero padding is provided. In accordance with an embodiment of the disclosure, a transmitter transmits data to a receiver by transmitting symbols such that each symbol is preceded by a cyclic prefix of a fixed length and the symbol conditionally includes enough zero padding to avoid ISI (Inter-Symbol Interference) between consecutive symbols. In some implementations, if the fixed length for cyclic prefixes is long enough to avoid ISI between consecutive symbols, then the symbols may omit zero padding. Otherwise, the symbols may include enough zero padding to avoid ISI between consecutive symbols. The zero padding may be zero tail or zero head.
摘要:
The present invention provides methods and devices for mitigating inter-cell interference in communication environments having a plurality of cells. In some embodiments, a time-frequency transmission resource that includes multiple sub-carriers over multiple OFDM symbol intervals is partitioned into a first zone and a second zone. In the first zone, transmissions are transmitted on at least one frequency sub-band which is common to all of the plurality of cells. In the second zone, transmissions are transmitted on at least one frequency sub-band which is used by less than all of the plurality of cells, so as to mitigate inter-cell interference. In some embodiments, in the first zone transmissions are transmitted using a transmission power which is common to all of the plurality of cells and in the second zone transmissions are transmitted using a transmission power which is used by less than all of the plurality of cells so as to mitigate inter-cell interference.
摘要:
In a method of transmitting a data stream from a transmitter in a multiple-input-multiple-output (MIMO) wireless communication system, where the transmitter comprises a plurality of transmit antennas, a discrete Fourier transform (DFT) is applied to the data stream to generate a plurality of symbol sequences; symbols of a first symbol sequence from the plurality of symbol sequences are paired with symbols of a second symbol sequence from the plurality of symbol sequences to generate a plurality of symbol pairs, wherein the pairing results in an orphan symbol; a space-time block code (STBC) is applied to the symbol pairs to generate a plurality of sets of STBC symbols, each set of STBC symbols being associated with a corresponding one of the plurality of antennas; a cyclic delay diversity (CDD) operation is applied to the orphan symbol to generate a plurality of CDD symbols, each CDD symbol being associated with a corresponding one of the plurality of antennas; and each one of the antennas transmits the corresponding set of STBC symbols and the corresponding CDD symbol.
摘要:
A method includes outputting a first graphical representation corresponding to a first group of one or more audio files and a second graphical representation corresponding to a second group of one or more audio files, wherein the first group is defined based on a respective first metadata attribute value for each audio file from the first group; receiving a user selection of the first graphical representation; and, in response to the user selection, moving the second graphical representation, thereby defining an expansion area, and outputting, within the expansion area, at least one additional graphical representation corresponding to a subgroup of the first group, wherein the subgroup is defined based at least in part on a respective second metadata attribute value for each audio file from the subgroup.
摘要:
To perform rank adaptation for a mobile station in a wireless network, it is determined whether the mobile station is fast moving. In response to determining that the mobile station is fast moving, an open loop multi-antenna mode is selected to perform wireless communication between the mobile station and a base station. Also, selection is made from among plural ranks for the wireless communication according to the open loop multi-antenna mode between the mobile station and the base station.
摘要:
Methods and articles for processing information to display a plurality of items. In one aspect, the method includes outputting, by a processor, data indicative of presentation of at least some of the plurality of items in a first configuration such that the plurality of items appear to be arranged for movement relative a central point; receiving an input signal indicative of a input path; determining a projection of the input path onto a notional line that corresponds to a trajectory of at least one of the plurality of items as it appears to move; and outputting data indicative of presentation of at least some of the plurality of items in a second configuration in which the plurality of items appear to have moved relative to the central point, wherein the apparent movement of the plurality of items is based at least in part on the projection.