摘要:
Wireless communications systems and methods related to over-the-air uplink-downlink (UL-DL) reciprocity calibration. A central unit transmits downlink (DL) calibration reference signal (RS) and a calibration request. The central unit receives, in response to the calibration request, a first uplink (UL) calibration RS and a first DL channel estimate associated with a first transmission point (TP) and a first wireless communication device. The central unit transmits a DL coordinated multipoint (CoMP) joint transmission signal according to an uplink-downlink (UL-DL) reciprocity calibration. The UL-DL reciprocity calibration is based on at least a first UL channel estimate based on the first UL calibration RS, the first DL channel estimate, a second UL channel estimate associated with a second TP and the first wireless communication device, and a second DL channel estimate associated with the second TP and the first wireless communication device.
摘要:
The Data Recovery with Inverse Transformation (DRIT) comprises methods and systems for reversing transmission channel transfer function in order to achieve a direct recovery of original data from a received signal distorted by a transmission link.
摘要:
Systems and techniques are disclosed to enhance the efficiency of available bandwidth between UEs and base stations. A UE transmits a sounding reference signal to the base station, which characterizes the uplink channel based on the SRS received and, using reciprocity, applies the channel characterization for the downlink channel. The base station may form the beam to the UE based on the uplink channel information obtained from the SRS. As the downlink channel changes the base station needs updated information to maintain its beamforming, meaning it needs a new SRS. Transmission of the SRS takes resources; to minimize this, the UE or the base station can determine a period during which the downlink channel will predictably remain coherent and set up a schedule for sending SRS. Alternatively, the UE or the base station can determine on demand that the channel is losing coherence and initiate an on demand SRS.
摘要:
Systems and techniques are disclosed to enhance the efficiency of available bandwidth between UEs and base stations. A UE transmits a sounding reference signal to the base station, which characterizes the uplink channel based on the SRS received and, using reciprocity, applies the channel characterization for the downlink channel. The base station may form the beam to the UE based on the uplink channel information obtained from the SRS. As the downlink channel changes the base station needs updated information to maintain its beamforming, meaning it needs a new SRS. Transmission of the SRS takes resources; to minimize this, the UE or the base station can determine a period during which the downlink channel will predictably remain coherent and set up a schedule for sending SRS. Alternatively, the UE or the base station can determine on demand that the channel is losing coherence and initiate an on demand SRS.
摘要:
A communication device operating in time division duplex (TDD) mode using multiple antennas is provided herein. The communication device uses receive channel estimation measurements to perform transmit beamforming and multiple input multiple output (MIMO) transmission, based on self-calibration of the various up/down paths via a method of transmission and reception between its own antennas, thus achieving reciprocity mapping between up and down links. Either user equipment (UE) or a base station may routinely perform this self-calibration to obtain the most current correction factor for the channel reciprocity to reflect the most current operating conditions present during TDD MIMO operation.
摘要:
The Clock and Data Recovery Techniques (CDRT) contribute Inverse Signal Transformation (IST) reversing transmission channel transfer function to achieve a direct recovery of original data from and synchronization of receiver clock to received signals affected by deterministic and random distortions introduced by the channel. The CDRT include also Phase Frequency Recovery Techniques (PFRT) and Direct Synthesis of Receiver Clock (DSRC) presenting feed-forward phase control configurations using an oscillator clock for synthesizing a receiver clock synchronous to a received data carrying signal.
摘要:
A transmission control device includes a memory; and a processor connected to the memory and configured to: specify layers corresponding to a number of hops of a link generated between a plurality of transmission points each of which wirelessly transmits a signal; and allocate radio resources which are used for transmission and reception of the signal and consecutive on a time axis to transmission points belonging to adjacent layers while sequentially switching the specified layers.
摘要:
The data recovery from sub-carriers (DRSC) of a received OFDM signal, contributes a method and a circuit for utilizing parameters of OFDM sub-carriers comprised in the received OFDM signal or subspaces comprising the OFDM sub-carriers for recovering transmitted data symbols from the received OFDM signal affected by deterministic and random distortions introduced by a transmission link.
摘要:
This application presents a direct data recovery from subspaces or parameters subranges of a received OFDM signal preidentified as corresponding to specific data symbols, by applying adaptive inverse signal transformation (AIST) method for reversing both original data coding and deterministic and random distortions introduced by a transmission channel, wherein both reversals are achieved by the same conversion of the subspaces or parameter subranges into data transmitted originally in order to eliminate an intermediate recovery of signals or parameters transmitted originally within the received OFDM signal. The AIST includes using both amplitudes and gradients of amplitudes of OFDM tone signals.
摘要:
The present invention relates to an apparatus and method for adaptive channel transmission using a channel state, and according to one embodiment of the present invention, a method for channel transmission of a remote node includes intermittently receiving a forward channel transmitted from a host node, estimating a reverse channel state based on the received forward channel, determining whether the estimated reverse channel state satisfies a preset channel condition, and adaptively transmitting a reverse channel based on the determined result.