251 results about "Multi user interference" patented technology

Provided are an apparatus and method for eliminating multi-user interference in a codebook-based beamforming system. A transmitter for providing a service to multi-users in the codebook-based beamforming system includes a beamformer for generating beamformed user signals by multiplying transmit data of users, to whom the service is to be provided, by corresponding weighting factor vectors using feedback information; a null space generator for generating a null space matrix orthogonal to weighting factor vectors of other users; and a projector for projecting the beamformed user signals on the corresponding null space matrix and transmitting the resulting signals through a plurality of antennas. Because the multi-user signals can maintain orthogonality, the performance degradation caused by the multi-user interference can be prevented.

A modem that provides efficient use of wireless network bandwidth in the presence of multi-user interference and noise comprising a multi-user detection module (115), a data formatting module (120), a control processor (125) and a demultiplexer (135).

The present invention relates to improved multiple access communications. In one form, the invention relates to an improved signal processing method and apparatus for an iterative method of determining the reception of a signal in a multi user packet based wireless OFDM (Orthogonal Frequency Division Multiplexing) communication system. In other forms the present invention provides recursive filtering for joint iterative decoding in a variety of systems and functions such as linear multiple access channel decoders, iterative equalisation, iterative joint channel estimation and detection / decoding, iterative space-time processing, iterative multi user interference cancellation and iterative demodulation. In one particular form the present invention provides an iterative decoding circuit for a wireless multiuser communications receiver comprising a first signal processing means for receiving at least one received signal, said first signal processing means comprising at least two linear iterative filters such that the first linear iterative filter provides an estimate of a selected received signal to an estimated signal output and a second linear iterative filter provides estimates of at least one other received signal, delayed by one iteration cycle, to an input of said first linear iterative filter, a second signal processing means for receiving the estimated signal output of the first linear iterative filter and providing a further received signal estimate to the input of the first signal processing means in a succeeding iteration cycle of the decoding circuit.

A Multi-User Detection device and method for DS-CDMA to allow enhanced signal reception under Multi-User Interference (MUI) at either the Remote Station or the Base Station is disclosed. The method includes the steps of relaying current channelization code use at Base Stations to Remote Stations operating in the vicinity of the Base Stations. This information is used by an MUD device at the Remote Station, to improve its ability to separate signals transmitted from different Base Stations. The downlink channelization code information is used to recreate the interference received by all neighboring Base Stations transmissions at the Remote Station. The same method can be applied at the Base Station side. The Uplink Channelization Code Usage information is relayed to each Base Station from its neighboring Base Stations. Recreating the total Remote Station interference at the Base Station allows a multistage interference cancellation based MUD to enhance its capability of receiving Remote Stations in its coverage area.

A method for allocating information transfer capacity in a mobile communication system, and a mobile communication system are provided. In the method according to the invention, the information transfer capacity is allocated to the user by forming a high capacity service site inside a cell of a base station by using a remote unit of a base station. The invention enables allocation of capacity to a specific mobile station with a low cost of multi-user interference generated to other receivers in the cell.

A receiver circuit identifies one or more interfering signals received with a desired signal by generating and evaluating one or more hypothesized interferers. By testing these hypotheses, such as through joint synchronization and channel estimation for the desired signal and the one or more hypothesized interferers, the circuit identifies which hypothesized interferer(s) best correspond to the dominant interfering signal(s) actually received. Channel models thus obtained for the dominant interferer(s) may be used in, for example, generating a whitening filter used in interference suppression, or jointly demodulating the desired and interfering signal(s).

The present invention relates to improved multiple access communications. In one form, the invention relates to an improved signal processing method and apparatus for an iterative method of determining the reception of a signal in a multi user packet based wireless OFDM (Orthogonal Frequency Division Multiplexing) communication system. In other forms the present invention provides recursive filtering for joint iterative decoding in a variety of systems and functions such as linear multiple access channel decoders, iterative equalisation, iterative joint channel estimation and detection / decoding, iterative space-time processing, iterative multi user interference cancellation and iterative demodulation. In one particular form the present invention provides an iterative decoding circuit for a wireless multiuser communications receiver comprising a first signal processing means for receiving at least one received signal, said first signal processing means comprising at least two linear iterative filters such that the first linear iterative filter provides an estimate of a selected received signal to an estimated signal output and a second linear iterative filter provides estimates of at least one other received signal, delayed by one iteration cycle, to an input of said first linear iterative filter, a second signal processing means for receiving the estimated signal output of the first linear iterative filter and providing a further received signal estimate to the input of the first signal processing means in a succeeding iteration cycle of the decoding circuit.

A modem that provides efficient use of wireless network bandwidth in the presence of multiuser interference and noise is disclosed. The modem design provides for compatibility with existing network hardware and protocols so that new efficient modems may be added to the network without removing installed hardware and software.

A method and an apparatus are provided for eliminating multi-user interference in a multi-antenna system. In a BS, precoding vector information of at least one interfering user terminal interfering with a user terminal and information about a ratio of the transmission (TX) power of the user terminal to the total TX power of the BS are detected. A control signal including the detected information is transmitted to the user terminal.

A DS-CDMA (Direct Sequence-Code Division Multiple Access) multi-user interference canceller cancels interference waves of a plurality of users. The DS-CDMA includes a variable gain controller for comparing reception characteristics of reception signals received from the plurality of users prior to interference cancellation processing with reception characteristics upon the interference cancellation processing and evaluating a comparison result, and controlling gains prior to baseband decoding of the reception signals so as to maximize improvements of the reception characteristics of the reception signals on the basis of an evaluation result. A CDMA multi-user system using the above canceller is also disclosed.

An interference relay channel (IRC) utilizes a single relay to assist communications between multiple source-destination links under the half-duplex (HD) constraint. It is assumed that each source has an independent message and its transmitted signal may cause interference at the other destinations. It is also assumed that each node only estimates its backward channels and has no knowledge of its forward channels as well as the other links. The role of the relay is to generate signals to cooperate with the intended signal and mitigate the interference at all destinations.

Provided is a radio communication system in which a base station apparatus with a plurality of transmission antennas spatially multiplexes and transmits a transmission signal addressed to a plurality of mobile station apparatuses, and in which the mobile station apparatuses receive the signal transmitted from the base station apparatus. The mobile station apparatuses select a desired precoding vector from predetermined candidates, and give the base station apparatus information identifying the selected precoding vector. The base station apparatus generates a linear filter on the basis of the information from the mobile station apparatuses, grasps multi-user interference that at least one of the mobile station apparatuses is subjected to when the generated linear filter is used, generates a new transmission signal by subtracting the multi-user interference from the transmission signal, and spatially multiplexes the transmission signal addressed to the plurality of mobile station apparatuses by multiplying the new transmission signal by the linear filter. Thus, favorable reception characteristics can be obtained while CSI feedback is performed efficiently.

The embodiment of the invention discloses a method and a device for pre-coding and decoding in a distributed multi-antenna system and relates to the technical field of wireless communication. By adopting the method and the device, the capacity of a multi-user interference system can be effectively improved, and the mutual interference among users can be reduced. The method for pre-coding in the distributed multi-antenna system comprises the following steps: getting an initial pre-coding matrix at the transmitting end; determining a receiving filter at the receiving end, wherein the receiving filter is orthogonal to an initial equivalent channel matrix of a channel which completely contains interference, and the initial equivalent channel matrix is got by utilizing the initial pre-coding matrix to calculate; performing multi-user pre-coding on an equivalent channel constituted by the receiving filter and the initial equivalent channel matrix, removing the interference in the initial equivalent channel matrix, and getting a pre-coding matrix at the transmitting end; and further performing the multi-user pre-coding through the pre-coding matrix. The method and the device can be widely applied in the technologies, such as LTE (long term evolution), LTE-Advanced, CoMP (coordinated multi-point) and the like.

The embodiment of the invention provides a multiuser interference suppression method, a terminal and a base station. The multiuser interference suppression method comprises the steps of layer-mapping and pre-coding business data of each user among matching users to obtain pre-encoded output data, mapping the pre-encoded output data and a public pilot frequency sequence to a port of an antenna array and sending the pre-encoded output data and the public pilot frequency sequence to each user. Correspondingly, the embodiment of the invention further provides a data receiving method, a base station and a terminal. All users among the matching users in a cell or a cooperation area use a same set of pilot frequency sequence based on the public pilot frequency sequence of the matching users. Unlike the existing technical scheme, a user-specific pilot frequency is not required in the invention. Pilot frequencies of different users must be orthogonal. Therefore, the number of matching users is not limited by the number of orthogonal pilot frequency sequences, the CoMP mode can be better supported, and the precision of channel estimation can be improved.

A method of mitigating narrow band interference (NBI) in ultra wide band (UWB) systems operating around 10 GHz mitigates multiuser interference from IEEE 802.22 and WiMAX, wherein the multiuser interference interferes with both trained and blind UWB systems, with the trained UWB system using pilot symbol assisted modulation. The method passes a received UWB signal through a band pass filter (BPF), wherein the BPF is located at a UWB receiver and the UWB signal is a Hanning modulated pulse centered at 4 GHz frequency. The method further measures a plurality of test functions, determines a number of active users, notch filters NBI signals, based on the determined number of active users, passes the notch filtered signal through a quadratic programming algorithm, to perform joint decoding, estimates an arrival of a UWB payload, and demodulates the UWB payload, based on the estimated arrival of the UWB payload.

A method for allocating information transfer capacity in a mobile communication system, and a mobile communication system are provided. In the method according to the invention, the information transfer capacity is allocated to the user by forming a high capacity service site inside a cell of a base station by using a remote unit of a base station. The invention enables allocation of capacity to a specific mobile station with a low cost of multi-user interference generated to other receivers in the cell.

The invention relates to an adaptive joint linear precoding method applicable to multi-base station coordination, belonging to the technical field of wireless communication. In the method, the multiple coordinative base stations form a coordination region; each coordinative base station acquires current channel status information from the coordinative base station to each user in the coordinationregion so as to obtain current channel matrixes; the coordinative base stations and signal leakage interference-to-noise ratios at the time of data transmission for the users are subjected to maximumprocessing to obtain anti-multiuser interference precoding matrixes; the equivalent channel matrixes of the users are subjected to singular value decomposition to obtain anti-multithread interferenceprecoding matrixes and decoding matrixes of the users for all corporative base stations; power allocation factors of the users are obtained in accordance with the channel matrixes; and the precoding matrixes of all coordinative base stations in the coordinative region for the jth user are obtained. The method has the advantages of low complicity and less overhead, is easy to realize, can be used to reduce the error rate in the wireless communication and improve transmission performance of communication systems, and particularly is suitable for a coordinative multiple point (CoMP) system of the multi-base station coordination.

The invention discloses an achieving method for MU-MIMO precoding. The method includes the detailed steps that a first precoding matrix is obtained through performing improved QR decomposition on expanding matrixes H of joint channel matrixes HS of all users to eliminate multi-user interference, precoding matrixes of all the users are determined according to a QR decomposition result, and therefore calculation complexity is reduced; then a lattice reduction method is used for obtaining a second precoding matrix better in performance. Compared with a traditional MU-MIMO precoding method, the method is lower in complexity, and meanwhile system performance is improved.

The invention relates to a joint multi-user detecting and decoding method based on a belief propagation algorithm and belongs to communication technical field, and in particular, relates to a joint multi-user detecting and decoding method for eliminating interference among multiple users based on a belief propagation algorithm in a multi-user communication system. The extrinsic information of bits and the extrinsic information of symbols of a user and are repeatedly iterated at encoding / decoding nodes and mapping / inverse mapping nodes. After the number of the iteration is satisfied, the joint multi-user detecting and decoding method may achieve joint interference elimination and decoding among multiple users. Compared with a conventional multi-user interference eliminating method, the joint multi-user detecting and decoding method is capable of effectively decreasing the computation complexity of an interference eliminating algorithm and increasing the performance of the interference elimination.

Provided are an apparatus and method for eliminating multi-user interference in a codebook-based beamforming system. A transmitter for providing a service to multi-users in the codebook-based beamforming system includes a beamformer for generating beamformed user signals by multiplying transmit data of users, to whom the service is to be provided, by corresponding weighting factor vectors using feedback information; a null space generator for generating a null space matrix orthogonal to weighting factor vectors of other users; and a projector for projecting the beamformed user signals on the corresponding null space matrix and transmitting the resulting signals through a plurality of antennas. Because the multi-user signals can maintain orthogonality, the performance degradation caused by the multi-user interference can be prevented.

An embodiment of the invention discloses a multi-input multi-output system data transmission method, a receiving method and a device thereof, wherein the data transmission method comprises the following steps: executing channel coding to the data information, interweaving, modulating and preprocessing the data information; and transmitting the data information which is executed with channel coding, interweaving, modulating and preprocessing to each receiving end, wherein the data information to be transmitted to each receiving end is interweaved respectively with different interweaving patterns. The receiving method comprises the following steps: receiving data information and interweaving pattern information; normally processing the data information; determining whether the data information which is processed normally passes through a CRC checking, if yes, obtaining the data information which is processed normally; and if not, executing iteration processing and then obtaining the data information. The embodiment of the invention can reduce the performance reduction caused by multi-user interference between the receiving ends of multi-input multi-output system thereby improving the capability of system.

The receiver includes the receiving antenna, the frame decomposition module (FDM), DFT-S OFDM demodulation module, and channel estimation disturbance elimination module (CEDEM). The receiving antenna is in use for receiving time domain radio signal of pilot signal with orthogonal code domain. FDM carries out decomposing sub frame for received signal in time domain so as to obtain time domain pilot signal with orthogonal code domain separated out from sub frame signal. DFT-S OFDM demodulation module demodulates the received time domain pilot signal. The demodulated pilot signal is sent to CEDEM. Removing out multi-user disturbance and multipath disturbance, CEDEM outputs user channel response in time domain or in frequency domain. The invention also discloses the system for estimating channel of pilot signal in up going multi-user code domain.

The invention discloses a precoding method, a precoding device, a decoding method and a decoding device, relates to the technical field of wireless communication, and realizes an excellent-performance interference alignment method. The capacity of a multi-user interference system can be effectively improved, and mutual interference between users can be reduced. The precoding method comprises the following steps of: calculating a precoding matrix of each transmitting end according to the sum of mean-square errors of a data vector to be transmitted by each transmitting end; and precoding the data of each transmitting end by utilizing the precoding matrix. The invention has wide application prospect, for example, the invention can be applied to long-term evolution (LTE), LTE-Advanced CoMP technology and the like.

The invention discloses a IDMA ascending and descending communication system based on time-division multiplex (TDD)and time reverse (TR), named as time-division multiplex time reverse interlace multiple address (TDR-IDMA)system, wherein the invention uses time-division complex to reversely rotate the respond time of channel impact and taking reverse value as the front signal processor at the receiver of ascending channel and the signal pre-treating device at the sender of the descending channel. Via the weak correlation of channel impact responses of different users, the front signal processor can effectively restrain multiple user interferences, thereby the iterate multi-user check at the receiver of base station can be quickly contracted, and the signal preprocessor at the sender of the descending channel can support the signal check of mobile terminal, and the time-division multiplex can arrange channel evaluator of mobile receiver to base station, to simply the complexity of descending receiver most and improve descending data transmission rate. Compared with traditional IDMA system, the TDR-IDMA has quick multi-user and simplified mobile device.

The invention discloses a signal-space-alignment-based common-channel multi-user interference suppression method, which mainly aims to solve the problem of common-channel multi-user interference. The method comprises that: in a multiple access stage in a first timeslot, a communication node transmits independent signals to other receiving communication nodes by a collaborative relay node, simultaneously receives signals from the other communication nodes, and performs signal space alignment on the signals expected to be subjected to network coding to reduce the number of independent information streams received by the relay node; and in a broadcasting transmission stage in a second timeslot, the collaborative relay node broadcasts and transmits the network coded signals, and each communication node eliminates interference signals in the broadcast signals by utilizing interface suppression beam forming, and decodes the network coded signals by utilizing own transmitted signals to obtain an estimated value of the signals expected to be received. By the method, the interference suppression technical advantages of the signal space alignment and the network coding are effectively fused, network capacity is increased, and bandwidth utilization rate is increased; and the method can be used for distributed transmission networks.

A double-antenna multi-carrier wave MIMO (multi-input and multi-output) communication method based on mutual complementing codes relates to a double-antenna multi-carrier wave communication method based on mutual complementing codes and solves the problems that the existing encoded MIMO system is poor in multi-user interference resisting performance, poor in multi-path interference resisting performance, and poor in Doppler effect capacity. The system adopts the mutual complementing codes to carry out spread spectrum, and adopts a multi-carrier wave system framework in signal emitting process; and the system adopts the mutual complementing codes to carry out demodulation spread in signal receiving process. The system adopts the mutual complementing codes to be used as spread spectrum codes of system carrier waves and adopts the multi-carrier wave system framework, so that the multi-user interference resisting performance of the MIMO system is greatly improved, under an AWGN (additive white Gaussian noise) channel, the complete multi-user interference resisting performance can be realized, under time selective fading brought by Doppler frequency shift, the system can resist multi-user interference with 75 percent rate, and under frequency selective fading caused by multi-path interference, the system can resist the multi-user interference with 50 percent rate.

The invention discloses a frequency deviation and phase deviation combination measurement method and an apparatus thereof. In the invention, during testing a mobile communication terminal, without regard to a condition of multi-user interference, the frequency deviation and phase deviation combination measurement method based on a matrix pretreatment mechanism is provided. The method is characterized by: using the structure matrix constructed previously to perform economical simplification QR decomposition; calculating least squares solution of a tropic of a sampling numerical curve so as to obtain the optimal solution of the frequency deviation and the phase deviation. By using the method and the apparatus of the invention, the combination measurement of the frequency deviation and the phase deviation can be realized. Compared to the prior art, an algorithm efficiency is higher and applicability is stronger.

The invention discloses an uplink multi-user code domain pilot channel estimation system. An training sequence generator is used for generating an M point pilot sequence and then transmitting the M point pilot sequence to a framing module; the framing module receives the pilot sequence demodulated by the DFT-S OFDM demodulation module and assembled into a sub-frame for transmitting to the antenna to send out; the frame decomposition module is used for carrying out a sub-frame decomposition to the time domain signal received by the antenna and obtaining the time domain pilot signal of the code domain orthogonality separated from the sub-frame signal; the DFT-S OFDM demodulation module is used for modulating the received time domain pilot signal and transmitting to the channel estimation interference elimination module; and the channel estimation interference elimination module is used for wiping out a multi-user interference and a multi-path interference, and outputting a user domain or frequency domain channel responding.