63 results about "Spatial multiplexing gain" patented technology

The invention discloses a multiple-input-multiple-output visible light MIMO system comprising a receiver which comprises multiple PD receptors; multiple light sources which are arranged at different positions, wherein the connecting lines between any two light sources of the multiple light sources and the receiver are not in the same straight line; and a controller which independently controls each light source to emit light signals in different power in a training phase respectively so that a gain matrix is obtained according to light intensity of each light source received by the receiver, multiple light sources are controlled to emit the light signals simultaneously in a communication phase, emitting power of each light source is obtained according to the gain matrix and light intensity received by the receiver at the time, and thus the light signals emitted by different light sources can be distinguished. According to the system of the embodiment, correlation among all sub-channels can be effectively reduced, spatial multiplexing efficiency can be enhanced and spatial multiplexing gain can be acquired.

A visible light communication (VLC) transceiver and a VLC system are provided. The VLC transceiver includes a substrate, a lens module and a plurality of channel units. The channel units are disposed on the substrate in an array to provide different bidirectional communication channels. Wherein, each of the channel units respectively includes at least a visible light emitter and at least a visible light receiver. The channel units can enhance communication bandwidth by using modulation technology such as spatial multiplexing or time multiplexing. The lens module is disposed on an optical path of the channel units. The lens module actively tracks the receiving situation of the visible light receiver to improve the signal quality of high-speed multiplexing communication.

In a wireless communication system a base station apparatus and a mobile station apparatus communicate with each other. The base station sets the number of spatial multiplexing sequences (rank) of data being used by the mobile station when transmitting a PUSCH, further sets orthogonal resources used by the mobile station for the same number of reference signals as the set number of spatial multiplexing sequences which are transmitted together with the PUSCH, and transmits downlink control information indicating the number of spatial multiplexing sequences and information indicating the orthogonal resources for the reference signals. The mobile station receives the downlink control information, selects orthogonal resources to respectively apply to the reference signals, applies the selected orthogonal resources to generate the reference signals, and transmits the generated reference signals to the base station apparatus.

A method is provided for transmitting radio signals. Two channels are defined by two transmit antennas, having two orthogonal directions, together with two receive antennas, having two orthogonal directions. An optimal quality of one received signal is determined by signal processing, which emulates a rotation of the two orthogonal receive directions, and a mutual interference of the signals received on the two channels, due to a polarization mismatch, is cancelled, based on a corresponding optimal rotation angle.

The invention discloses a rate-self adaptive method under spatial multiplexing in millimeter wave high speed communication. An algorithm based on static analysis and an algorithm based on dynamic link quality measurement are combined to select an appropriate transmission rate. A short time frame error rate is calculated through static analysis of the number of ACKs successfully received in a BlK-ACK (block acknowledgment) frame, the short time frame error rate is compared with a preset threshold to decide whether to adjust the rate, RSSI information and an available MCS are combined to determine whether to adjust the rate, an appropriate rate is selected, then transmitting power is adjusted, and the handling capacity is further improved. The rate-self adaptive method under spatial multiplexing in millimeter wave high speed communication has robustness, and the problem of repeat rate jump is solved to a large extent. Meanwhile, the transmitting power can be adjusted in a self-adaptive mode, the transmitting power is reduced to reduced interference of a communication link with other communication links, potential multiplexing power is increased, and integral performance of the system is improved.

A system for optimizing power allocation for each optical transmitter in an optical transmission system, the system comprises at least two intensity modulated optical transmitters, each of which is controlled by a modulator; an optical channel that can be spatially multiplexed by a multiplexer; and at least two optical detectors, for detecting the transmitted modulated signals. Each of the modulators are adapted to modulate the transmitters such that the electrical power consumption of the optical transmitters is minimized by a modulation scheme of the modulators, that uses energy efficient convex optimization to multiplex the transmitted optical signals, by the multiplexer in a multiple-input-multiple-output (MIMO) scheme. Each of the modulators are adapted to modulate the transmitters such that the capacity is maximized by a modulation scheme of the modulators, that uses energy efficient convex optimization to multiplex the transmitted optical signals, by the multiplexer in a multiple-input-multiple-output (MIMO) scheme.

An apparatus and method for selecting antennas and nodes in a multi-input multi-output (MIMO) communication system are provided. The apparatus includes a reception unit which detects a communication initiation signal from among a plurality of received signals, a first combination unit which calculates communication capacity based on the communication initiation signal, searches for a combination of transmission antennas that can maximize the communication capacity, and performs communication using the identified combination of transmission antennas, a second combination unit which calculates an average signal-to-noise ratio (SNR) of each node based on the communication initiation signal and selects a node with a highest average SNR and performs communication using the selected node, and a selection unit which activates one of the first combination unit and the second combination unit and inactivates the other combination unit. When the quality of signals transmitted between wireless nodes deteriorates due to a poor channel environment, a node that can minimize the shadowing effect caused by an obstacle that blocks the path of transmission of signals is selected using space diversity. Therefore, it is possible to minimize link communication failures. In addition, it is possible to maximize communication capacity by achieving spatial multiplexing gain using an array antenna that is mounted on a node.

The invention discloses a direction antenna spatial multiplexing method for a millimeter wave system. Firstly, an information collection mechanism and evaluation criteria are defined, and then the following steps are carried out. The steps comprise 1, feeding back beam reference pairs of a transmitting and receiving end to a PCP/AP in a beam forming process, thereby forming a beam reference pair information table BFT; 2, transforming the beam reference pair information table BFT into a link beam difference value table LDT; 3, performing a spatial multiplexing dispatching algorithm, and generating an optimum link dispatching method; and 4, sending a generation scheme to each STA by the PCP/AP through BTI, and performing the generation scheme in a next SP period by the STA. According to the method, the detection time of signal interference between links is reduced, the simple, easy-judging and effective evaluation criteria are designed, the feasible, fast and effectively dispatching scheme is provided, the spatial multiplexing gain can be effectively improved, and the throughput of the whole millimeter wave system can be improved.

The invention provides a double-bounce half-duplex MIMO (Multiple-input Multiple-output) relay network distributed type beam forming method, and provides two distributed type beam forming schemes, namely, RZF (Regularized Zero Forcing) and IRZF (Information Regularized Zero Forcing)-MF (Matched Filter), which take a multi-antenna multi-relay double-bounce half-duplex wireless network into account, are based on RZF precoding technology and MF technology, and are suitable for a rice channel. At a relay node, beam formation is received and transmitted by utilizing the RZF technology in the RZF scheme, and the beam formation is received and transmitted by respectively utilizing the IRZF technology and MF technology in the IRZF-MF scheme. According to the schemes, the relay node is required to obtain self channel state information in the forward direction and the backward direction, at a target node, a QR receiver is used for continuous interference eliminating detection to obtain maximum spatial multiplexing gain. The test result shows that the two schemes provided by the invention can be completely suitable for rice channel conditions, and the channel capacity approximate to the upper bound of the capacity can be obtained under the channel conditions.

Disclosed are an apparatus and a method for detecting signals in a spatial multiplexing system. An embodiment of the invention provides a signal detection apparatus for a single receiver unit equipped with a plurality of antennas in a system having at least one transmitter unit configured to transmit data streams by spatial multiplexing, where the signal detection apparatus includes: a partial linear coefficient generator unit configured to generate a linear weighting matrix by using a preset algorithm on a channel matrix formed between the transmitter unit and the single receiver unit; a partial symbol remover unit configured to generate a first symbol vector by removing all transmittable symbols for each transmitting antenna from all received data streams; and a partial symbol detector unit configured to generate a transmission symbol candidate vector by using the linear weighting matrix and the first symbol vector.

The invention discloses a spatial multiplexing link scheduling method applied to a millimeter wave WPAN. The method includes the following steps that firstly, a signal detection broadcasting period in which interference is directionally measured is set before time slot allocation of a current signal transmission frame is started; secondly, a co-channel mutual interference statistical table of links is established; thirdly, allowed link interference tolerance values of the links are calculated, and a link interference tolerance table is established; fourthly, according to the number of the links, the current signal transmission frame is divided into multiple time slots corresponding to the links one by one, each link serves as a main link in the corresponding time slot, and other links allowed simultaneous transmission to be conducted except for the main links are determined in the corresponding time slots according to the method that actual interference values among the links are compared with the interference tolerance values of the links. According to the link scheduling method, all the links can be connected in the same transmission period, fairness of the links is guaranteed to a certain degree, spatial multiplexing gains are utilized to the maximum degree, priority is given to the links which slightly interfere with the main links to enter the corresponding time slots, each time slot can contain the parallel links as many as possible, and system throughput is maximized.

The invention provides a multi-channel multiple access method based on an MIMO transmission mechanism. During the competitive stage, a node reuses a data antenna to carry out channel competition in a common control channel, after the channel competition is successes, selection of the data channel and confirmation of data transmission period duration are completed through interaction information in a 2*2MIMO manner, and during a transmission stage, the node reuses a control antenna to transmit a data packet in a data channel. The multi-channel multiple access method based on the MIMO transmission mechanism is simple to implement, and can be implemented in firmware which supports multi-channel network cards, and can be implemented in a driving program at the same time, and the network throughput is greatly increased; by employing a distributed working mode, a centralized control node and whole network time synchronization are not needed, a control packet and the data packet can be transmitted in a 2*2MIMO transmission manner, substantial spatial multiplexing gain can be brought about, furthermore the system performance is greatly improved, the network throughput is increased, and the end-to-end time delay is reduced.

A transmission method using a massive MIMO (Multiple-Input and Multiple-Output) scheme with an arrangement 108 of N_m×N_b antenna elements at the transmitter, arranged in N_m sets of N_b antenna elements or N_b sets of N_m antenna elements based on SC-FDE (Single-Carrier with Frequency Domain Equalization) schemes with large constellations that is compatible with low-cost, highly-efficient, nonlinear amplifiers 106, while allowing spatial multiplexing gains.

The transmission structure of this transmission method decomposes in 103 the modulated symbols from 102 associated to a given constellation as the sum of N_m polar components that are modulated as N_m BPSK (Binary Phase Shift Keying) signals. Each of these BPSK signals can be regarded as an OQPSK (Offset Quadrature Phase Shift Keying) signal in the serial format that is specially designed to have good tradeoffs between reduced envelope fluctuations and a compact spectrum.

The invention belongs to the technical field of wireless communication, and in particular relates to a superimposed pilot method based on spatial multiplexing in a large scale MIMO system, applied toan uplink multi-cell multi-user large scale MIMO system. The superimposed pilot method comprises the following steps of designing a sending signal and processing a received signal; performing channelestimation according to the received signal and by using an MMSE estimation method; using maximization of a signal to noise ratio as an optimization target to determine the optimal power distribution;and improving channel estimation via iterative operation. Compared with the traditional pilot method based on spatial multiplexing, the superimposed pilot method based on spatial multiplexing can achieve higher throughput of system, and the provided iteration algorithm can improve channel estimation and thus further enhance system performance.

The invention discloses a co-frequency co-time full duplex communication system and method based on spatial modulation. According to the invention, a sending information flow is divided into an antenna selection information flow and a constellation modulation information flow by using the spatial modulation technology, the antenna selection information transmits one part of sending information, and the emission symbol obtained after constellation modulation transmits the other part of sending information, so that the spatial multiplexing gain of the communication system is improved; a precoding vector is obtained through a self-interference channel matrix, a transmitting symbol is multiplied by the precoding vector, and is eliminated on a receiving antenna, so that the part of antennas canbe used for receiving same-frequency simultaneous signals from another communication node, and a same-frequency simultaneous full duplex communication mode is realized; and the combination of the twomeans improves the spectral efficiency of the communication system.

The invention provides a method and a device for determining a downlink weight vector of multiple pieces of user equipment. The method comprises the following steps that: a base station acquires an accuracy alpha<l> of channel state information of each piece of user equipment; the base station determines a value of each element beta<l,i> in a weight projection expected matrix beta according to a relationship between a module value square alpha<2> of accuracy information and a reciprocal (defined in the description) of a total number of transmitting antenna dimensions; and the base station determines the downlink weight vector of each piece of user equipment in the multiple pieces of user equipment according to the weight projection expected matrix beta. According to the method and the device in the embodiment, the accuracy of the channel state information of each piece of user equipment is taken as one of bases for determining the downlink weight vector, so that the determined downlink weight vector is closer to a practical situation of a communication system compared with the prior art in which the accuracy of the channel state information of each piece of user equipment is assumed to be an ideal value, thereby achieving a higher spatial multiplexing gain.