484results about How to "Reduce Feedback Overhead" patented technology

There is provided a method for configuring a power distribution within a cellular network system. The cellular network system includes at least one cooperation area. The at least one cooperation area is defined by at least two base stations, each including at least one antenna, wherein each base station has at least one beam. The method includes configuring the base stations to transmit at a first transmit power level for providing a first receiving power level for a user equipment at a center region of the cooperation area, and configuring the base stations to transmit at a second transmit power level for providing a second receiving power level at a border region of the cooperation area, wherein the second receiving power level is lower than the first receiving power level.

A space-time-frequency domain based information feedback method, system, user equipment and base station for wireless transmission technical fields is provided. The user equipment measures and evaluates quality of wireless transmission downlinks in MIMO system, obtains rank, precoding matrix index and channel quality indicator information in the wireless transmission downlinks, processes information of the wireless transmission downlink respectively in space domain, frequency domain and time domain by using space selectivity, frequency selectivity and time selectivity characteristics of a channel, and feeds back downlink information to the base station through uplinks by using feedback schemes. The base station optimizes a transmitter according to feedback information from the user equipment.

The invention provides a pre-coding method for an MIMO (multi-input multi-output) system of 8 transmitting antennas. A dual code text is adopted in the method, and the dual code text is determined by selectively succeeding partial code words of LTE (long term evolution) and then performing certain extension. The method for pre-coding by using the dual code text reduces the feedback overhead of the system, acquires good performance gain, and is suitable for a multi-user multi-input multi-output (MU-MIMO) system.

The invention discloses a method for multi-input multi-output transmission for precoding. The method comprises the following steps: a fundamental matrix is selected, a column vector is selected from the fundamental matrix according to the dimension of a precoding matrix under each rank, the precoding matrixes are combined into codebooks, and the codebooks are respectively stored into the transmitting end and the receiving end of a multi-input multi-output transmission system; the receiving end selects precoding matrixes from the codebooks, and feeds back the indexes thereof to the transmitting end; the transmitting end uses the precoding matrixes corresponding to the indexes when the next transmission is performed, performs linear transformation in spatial domain to signals to be transmitted and then transmits the signals. The invention also discloses a method for multi-input multi-output codebook coding for precoding. The method enables the system to meet the feedback expenses and obtains good performance gain.

Embodiments of the present invention generally relate to methods and apparatuses for the channel measurement and feedback of a multi-dimensional antenna array. Specifically, according to embodiments of the present invention, the primary inventive idea is to allow a base station equipped with a multi-dimensional antenna array to configure more than one class of CSI-RS, wherein each class of CSI-RS is for use in a channel measurement at the UE for a different dimension of the multi-dimensional antenna array. The base station then transmits the generated configuration information to the UE so that the UE may perform channel measurement specific to different dimensions, for example, by selecting different codebooks for the channel measurement for different dimensions. In this way, it is possible to increase the channel measurement precision of the multi-dimensional antenna array, reduce the measurement feedback overhead and improve the system performance.

The invention discloses a method for multiplexing the uplink control information (UCI) in an uplink channel. Firstly, the UCI is classified by the UE, and different types of the UCI are respectively subjected to encoding, rate matching and modulating. Secondly, the UE respectively maps different types of the UCI on the uplink channel. The invention also discloses a method and a device for multiplexing the P-CSI and the A-CSI in the uplink channel, a method and a device for determining the number of modulation symbols occupied by the UCI, and a method and a device for determining an uplink physical resource block for uplink transmission. The invention provides a general physical resource mapping method for processing various types of the uplink information, and ensures the reliability requirements of different types of the UCI information. Meanwhile, the P-CSI fed back together with the A-CSI is optimized, so that the feedback overhead is reduced. Moreover, uplink channel resources allocated by a base station can be fully utilized. Therefore, the utilization rate of uplink resources is increased.

A system and method for reduced feedback in MU-MIMO communications is provided. A method for transmitter operations includes transmitting a pilot signal, receiving channel information feedback from a set of K communications devices served by a transmitter, where K is a non-negative integer value and K≧2, selecting M communications devices out of the set of K communications devices, where M is a non-negative integer value and M≦K, computing a precoder for each of the M selected communications devices based on the channel information feedback, and simultaneously transmitting information to the M selected communications devices. The channel information feedback includes partial information for a communications channel between the transmitter and a communications device, the selecting being based on the channel information feedback, and the information transmitted to each communications device in the M selected communications devices being precoded using a computed precoder associated with the communications device.

A communication apparatus capable of improving the spectrum usage rate of a system, especially, the spectrum usage rate in connection with both a fast fading and a channel estimation error as compared with the conventional sub-band adaptive method, while reducing the degree of the difficulty in achieving the adaptation, and further reducing the feedback overhead. In this apparatus, a sub-band group AMC parameter selecting part (318) selects an AMC parameter of each sub-band. An adaptive reception control part (503) must control an adaptive demodulating / decoding part (311), while controlling a parallel / serial converter (312) in a stage preceding the adaptive demodulation and decoding processes, and combining received symbols in the same sub-band group for demodulation and decoding.

A system and method for wireless communications with adaptive codebooks are provided. A method for communications node operations includes estimating a communications channel between the communications node and a controller serving the communications node, quantizing the estimated communications channel based on an adapted codebook, estimating statistics of the communications channel, transmitting a first indicator of the quantized estimated communications channel, adjusting the adapted codebook based on the estimated statistics, and receiving a transmission from the controller. The transmission is precoded based on the first indicator of the quantized estimated communications channel.

A method and apparatus of transmitting data in a coordinated multi-cell wireless communication system is provided. A base station receives information about beam-forming vectors, aligned with a channel to a user equipment placed in a neighbor cell, and about nulling beam-forming vectors for the channel to the user equipment from the neighbor cell, determines a transmission beam-forming vector based on the information, and transmits data to the user equipment using the transmission beam-forming vector.

The invention discloses a resource reuse method and a resource reuse system for improving the energy efficiency of a D2D (device-to-device) system. The method comprises the following steps that 1, the position estimation is carried out on the emitting end and the receiving end of D2D user pairs, and the position information is obtained; 2, whether the distance from the sending end to the receiving end is greater than the threshold value or not is judged according to the position information, when the distance is greater than the threshold value, the current timeslot idle cellular users are selected to be used as a relay node, in addition, the operation enters the third step, and otherwise, the operation directly enters the third step; 3, the cellular users with resources distributed by a base station and each group of D2D users are respectively combined, and an energy efficiency matrix and a velocity matrix are built; 4, the resource reuse decision making is carried out on the basis of the preset criterion, and the channel reuse matrix is obtained through solving; 5, the reuse cellular users of each group of D2D user pairs and the corresponding optimum emitting velocity are determined. The resource reuse can be carried out at the same time as the expenditure reduction realization only according to the position information of users in a cell, and the total energy efficiency of a communication system is improved.

The present invention relates to a beamforming method and apparatus. A beamforming method for use in a base station for transmitting a plurality of streams through a plurality of antennas includes: receiving feedback information including information on a first codeword selected from a codebook including a plurality of codewords from each of a plurality of user terminals; grouping the plurality of user terminals by use of the feedback information from each user terminal; determining a user terminal to which a plurality of streams will be assigned of the plurality of user terminals, and determining a second codeword to be used for beamforming from the codebook by use of the feedback information of each user terminal and grouping information; and multiplying data to be transmitted through the plurality of steams by the second codeword and a unitary matrix.

A spatial channel state information (CSI) feedback technique is incorporated into multiple-input multiple-output mobile communications technologies. Spatial channel state information is measured at receiving equipment and then decomposed into components. The components are then quantized using codebook(s) and fed back as multiple indices to transmitting equipment.

The invention discloses a multi-user multiple input multiple output (MU-MIMO) transmission method in a wireless communication system, a base station and a user terminal. The method comprises the following steps that: the base station receives detection pilot frequency SRS of N users to perform channel estimation and acquires downlink channel information according to the channel estimation result and channel reciprocity of the system, wherein N is more than 1; the base station performs quick response (QR) decomposition on the downlink channel information, acquires a multi-user beamforming (MU-BF) matrix P (i) of the ith user from a Q matrix acquired through decomposition, and acquires a downlink single-user beamforming (SU-BF) matrix V (i) of the ith user further, wherein i=1, ...,N; and the base station performs beamforming processing on transmitting data of the ith user according to the MU-BF matrix P (i) and the SU-BF matrix V (i). The method and equipment acquire beamforming matrixes for uplink and downlink MU-MIMO transmission by means of the channel reciprocity of the system and the QR decomposition, and the MU-MIMO transmission performance can be improved.

The invention relates to a spatial-orthogonality-based large-scale MIMO system pilot frequency distribution method. The method comprises the following steps: 1) obtaining the statistical covariance matrix information of every user terminal channel through a base station; 2) under the condition that the statistical covariance matrix information is known, obtaining the condition for achieving no-speed-loss transmission when two users located in different cells on the same time-frequency block perform pilot frequency multiplexing; 3) according to the information obtained in step 1), contrasting and calculating the spatial orthogonality degree among the channels of different users through the base station, and utilizing the condition of achieving the no-speed-loss transmission in step 2) to perform greedy packet scheduling on the users under the principle of maximizing the system sum speed; and 4) performing pilot frequency distribution on every user group. Under the condition that the user side does not know instantaneous channel state information, the spatial-orthogonality-based large-scale MIMO system pilot frequency distribution method can achieve the pilot frequency multiplexing and meanwhile effectively reduce the influence caused by the problem of pilot frequency pollution and improve the system throughput performance.

The present document provides a method for feeding back channel state information and a user equipment. The method includes: a user equipment determining a second parameter y of a feedback mode according to the number of Channel-State Information-reference signals (CSI-RS) ports configured by a high layer signaling or according to the number of CSI-RS ports and indication information indicating whether to feed back a pre-coding matrix indicator (PMI) and rank indicator (RI); the user equipment determining the feedback mode according to a transmission mode configured by the high layer signaling, a first parameter x of the feedback mode and the second parameter y of the feedback mode; and the user equipment feeding back the channel state information according to the determined feedback mode. The present document improves the system flexibility and performance and reduces the feedback overhead.

The invention discloses a large-scale MIMO time-varying channel state information compression feedback and reconstruction method. The method comprises the steps that a channel matrix sequence is acquired, T channel matrixes are subjected to DFT separately, and a channel matrix sequence which is sparse in the angle delay domain is obtained; a channel feedback and reconstruction model CsiNet-LSTM isconstructed, the channel matrix sequence is input to a coder, and codewords are output; the codewords are sequentially input to a decoder, and a reconstructed channel matrix sequence is output; the channel feedback and reconstruction model is trained to gradually approximate to the channel matrix sequence to obtain model parameters; each channel matrix in the output reconstructed channel matrix sequence is subjected to two-dimensional inverse DFT, and a reconstruction value of an original space-frequency domain matrix sequence is obtained through recovery; and channel state information to befed back and reconstructed is input to the model, and a reconstruction value is output. According to the method, the feedback overhead of large-scale MIMO channel information can be reduced, the reconstruction precision is improved, and the excellent robustness is particularly achieved on decrease of the compression ratio.

The invention discloses a method for determining a feedback codebook, a terminal device, and a network device. The method comprises the steps: enabling a receiving end device to obtain time unit aggregation information and DAI indication information transmitted by a transmitting end device, and determining the feedback information of at least one transmission block according to the time unit aggregation information and DAI indication information; finally transmitting the feedback information of at least one transmission block to the transmitting end device. The method can improve a mode that an NR system determines the HARQ feedback information, so as to support a scenario of the aggregation or dispatching of a flexible number of time units, thereby preventing the terminal device and the base station for understanding the HARQ feedback information inconsistently and wrongly while guaranteeing the downlink control overhead and uplink feedback overhead.

The invention provides a method and a device for feeding back channel state information. The method for feeding back the channel state information includes the following steps: determining a first category of channel state information (CSI) based on a variety of assumed conditions, sending the first category of the CSI to a base station, receiving configuration signaling which is sent by the base station, wherein the configuration signaling is used for indicating a part of assumed conditions which are selected by the base station according to the first category of the CSI from the variety of the assumed conditions, and sending a second category of the CSI based on the part of the assumed conditions to the base station. According to the method and the device for feeding back the channel state information, the first category of the CSI based on the variety of the assumed conditions and the second category of the CSI based on the part of the assumed conditions are fed back to the base station through user equipment (UE), all the CSI of a plurality of transfer points does not need to be fed back, and therefore feedback overhead is reduced.

Multipoint broadcasting requires the base stations to be phase-synchronized. Methods and apparatus are described that provide phase synchronization of base stations with the downlink-channel phase feedback by mobile users. Also described are methods and apparatus that make phase synchronization of base stations independent of multipoint-broadcast sessions, thus reducing the synchronization overhead and improving network capacity. The methods and apparatus utilize model-based downlink-channel phase feedback that reduces most of the feedback overhead. Applications of the described methods and apparatus include wireless multipoint broadcast systems, also known as coordinated multipoint transmission, or CoMP, in LTE-A (long-term evolution, advanced) systems, and frequency and phase synchronization of a cluster of base stations, or more generally, of a cluster of wireless devices.

A collaborative MIMO method using a sounding channel in a multi-cell environment is disclosed. The method includes acquiring, by a first base station providing a service for a first cell, first CSI of a first downlink channel between the first base station and a mobile station, transmitting, to a second base station, a signal including information requesting that the second base station providing a service for a second cell acquire second CSI of a second downlink channel between the second base station and the mobile station, and acquiring, by the second base station, the second CSI. The mobile station is served by the first base station.

The invention provides a method and a device for selecting a precoding matrix. The characteristics that a gap between adjacent antennae of tightly spaced cross polarization linear array antennae is small, the diagonal elements of a correlation matrix are 1 and the like are fully considered, and a corresponding code book for the quantification and feedback of the correlation matrix is designed, so that high system performance is achieved at low feedback overhead and complexity.

The invention discloses a large-scale MIMO channel joint estimation and feedback method based on deep learning. The method comprises the steps: performing initial channel estimation at a user side; constructing a channel estimation subnet CEnet, and minimizing the estimation error through training; constructing a channel feedback subnet; at the user side, inputting the optimized channel estimation value, and outputting compressed code words; at the base station end, inputting the code words, and outputting the reconstructed channel matrix. And the two subnets jointly form a channel estimation and feedback joint network CEFnet. A previous CSI feedback network assumes that perfect channel state information is obtained, does not consider that a channel in practice is obtained by estimation, and has errors and noise. According to the invention, a complete downlink channel estimation and feedback process is realized by constructing a channel estimation and feedback joint network CEFnet, the purpose of eliminating errors and noise is achieved by using a brand new network architecture, and the reconstruction precision is improved while the feedback overhead is reduced.

An apparatus and method for transmitting / receiving a Channel Quality Information (CQI) in a communication system are provided. A Mobile Station (MS) receives first information indicating a representative MS selected from a group of MSs located within a preset range and in similar channel statuses, the group including the MS, determines from the first information whether the MS is designated as the representative MS, and transmits a CQI of the MS as a representative CQI of the MSs included in the group to a Base Station (BS), if the MS is designated as the representative MS.

The invention provides a method for scheduling downlink transmission executed at a network node, and the corresponding network node. The method comprises the steps of detecting the maximum number of CBGs that can be segmented in each transmission block (TB) of downlink transmission according to the number of the TBs scheduled in downlink transmission to be implemented and the maximum number of coding block groups (CBGs) that can be segmented in downlink transmission; based on the maximum number of the CBGs that can be segmented in each TB of downlink transmission, determining CBG configurationof the scheduled CBG in the corresponding TB; and sending a downlink control signal used for instructing the CBG configuration. In addition, the invention also provides a method for feeding back a hybrid automatic retransmission request acknowledgement (HARQ-ACK) executed at the user equipment (UE), the corresponding user equipment, and a communication system comprising the network node and the user equipment.

The invention discloses a feedback method for channel state information. The feedback method includes the steps that UE receives a mode which is configured by a base station and used for reporting the channel station information (CSI); the UE measures a base station signal and interference, determines a rank, pre-coding matrixes and CQI used for downlink transmission under the current channel condition and obtains PMIs for instructing the pre-coding matrix according to the pre-coding matrixes; the UE reports the rank, the PMIs and the CQI in the uplink direction. A codebook used for feeding back the CSI is a sub-codebook of a standard codebook, and the higher the correlation between any two codes in the codebook is, the smaller the code distance between the two corresponding PMIs is. The feedback method can be applied to improving the transmission performance of a system.

The invention discloses a feedback method of channel quality information (CQI) and a terminal. In the method, the terminal feeds back CQI to the network side, wherein CQI comprises the wideband CQI index of the serving cell and the wideband differential CQI index offset level of each coordinating cell in a plurality of coordinating cells; and the wideband differential CQI index offset level of the coordinating cell is the wideband CQI index of the serving cell minus the wideband CQI index of the coordinating cell. The technical scheme provided by the invention solves the problem that the overhead is high when the terminal feeds back CQI during CoMP transmission in the related art, thus further reducing the feedback overhead of the terminal.

A system and method for channel status information feedback in a wireless communications system is provided. A method includes receiving a transmission containing feedback information from a mobile station (MS) having N total antennas, M receive / transmit antennas, N−M receive-only antennas, wherein N and M are integers and N>M, decoding the received transmission, computing estimates of CSI for channel elements of N−M receive-only antennas using the decoded transmission, computing estimates of CSI for channel elements of M receive / transmit antennas using channel reciprocity, and computing a precoding matrix from the channel elements for the N−M receive-only antennas and the M receive / transmit antennas.

The invention discloses a method and a device for sending a sounding reference signal. The method comprises the following steps of: allocating sounding reference signal resources for detecting each cell to user equipment in at least two cells of which uplink channels need to be detected by the user equipment; instructing the user equipment to send the sounding reference signal on the allocated sounding reference signal resources. The user equipment can detect the channels of a plurality of cells by using the method; and the method is used for multi-point cooperative transmission, can prevent the user equipment from feeding back the channel information of the plurality of cells, reduce the feedback expenses and improve the system performance.

A system for link adaptation in a MIMO-OFDM system. In this system, the V-BLAST processor (308) performs V-BLAST processing and separates receive signals for the multiple antennas of the transmitter into data streams. The vector information output section (312) sends feedback vector information obtained from V-BLAST processing to the transmitter. The adaptive bit assignment section (304) adaptively controls the number of bits to be assigned to each of the sub-carriers on different antennas, based on the feedback vector information. The adaptive power allocation section (306) adaptively allocates power to each antenna, based on the feedback vector information.