51 results about "Cooperative beamforming" patented technology

A system and method for opportunistically designing collaborative beamforming vectors is disclosed for a wireless multiple input, multiple output (MIMO) space division multiple access (SDMA) communication system by sequentially designing beamforming vectors for ranked channels in order to exploit the instantaneous channel conditions to improve per user average SNR performance. Each subscriber station independently transmits information to a base station that allows the base station to determine beamforming vectors for each subscriber station by ranking the subscriber stations by channel strength. Using sequential nullspace methods, the ranked channel matrices are then used to select the channel matrix H_i for the best subscriber station, to design the w_i, v_i for the best subscriber station as the left and right singular vectors of the MIMO channel matrix H_i, to transform the remaining channels and to continue the process until beamforming vectors are designed for all channels.

A method for estimating a communication channel comprising one or more sub-channels between at least a first transceiver and at least a second transceiver is provided. The method comprises transmitting a first set of training data from the first transceiver to the second transceiver, receiving observed signals at the second transceiver, re-transmitting said observed signal back to the first transceiver, and calculating a roundtrip channel estimate at the first transceiver. The method further comprises transmitting a second set of training data from the second transceiver to the first transceiver, receiving observed signals at the first transceiver, and calculating a reverse link channel estimate. From the roundtrip channel estimate and the reverse link channel estimate, a forward link channel estimate is computed at the first transceiver.

Disclosed is a protocol for transmitting data through cooperation between access points in an overlapped basic service set (OBSS) environment. A cooperative beamforming communication method may include negotiating, by a first access point, a cooperative transmit beamforming with a second access point having an OBSS area with the first access point; transmitting, by the first access point, a clear-to-send (CTS) to the second access point; and performing, by the first access point, the cooperative transmit beamforming with the second access point during a cooperative transmit beamforming duration determined through the negotiation after a predetermined time interval is elapsed, when transmission of the CTS is completed.

The present invention relates to a method for operating a secondary station in a network, the secondary station comprising a transceiver adapted for simultaneously receiving transmissions from a primary station controlling a first cell and at least one primary station controlling a second cell, the method comprising the secondary station

• • (a) selecting a first precoding matrix for the first cell out a primary set of precoding matrices for the first cell,
  • (b) selecting a subset of at least one precoding matrix for the at least one second cell in dependence on the first precoding matrix, out of a set of subsets of precoding matrices for the second cell,
  • (c) selecting a second precoding matrix for the at least one second cell out of the selected subset of precoding matrices for the second cell,
  • (d) transmitting a first indicator representative of the first precoding matrix.

Certain aspects of the present disclosure support techniques for cooperative beamforming based on inter-cell coordination. Signaling design allows coordinated downlink transmissions with reduced inter-cell interference.

The invention discloses a cooperative beamforming method for a large-scale MIMO system, and belongs to the field of wireless communication. The method comprises the steps: constructing a downlink large-scale MIMO heterogeneous network among a macro base station, a small base station and a user; considering the circuit power consumption of the base station, researching a system energy efficiency optimization problem satisfying QoS and antenna transmitting power constraints, and fully mining characteristics of a neural network; through the satisfactory performance of deep learning in regressiveproblems, fitting an optimal beamforming solution by extracting channel gain matrix characteristics; performing offline training by utilizing the neural network, and transferring a part of calculationto an offline part. Only a small amount of linear and nonlinear calculation is needed when the trained neural network is applied to solve, and the time delay is greatly reduced while the energy efficiency of the system is improved.

The invention discloses an information energy cooperative beam forming method based on a cognitive two-way relay network. According to the invention, the secondary user sending ends of multiple antennas collect energy from the signals of a primary user according to a power allocation scheme so as to forward the signals of the primary user and send their own signals. The purpose of the invention isto design beam forming matrixes, vectors and power allocation factors suitable for secondary user sending ends, so that the achievable rate at each secondary user is enabled to be maximal. Herein, the ideal channel state information for all known links of the secondary user sending ends is considered, and an optimization scheme based on Charnes-Cooper translation and one-dimensional search is provided. Through introducing the semi-definite relaxation method, an original optimization problem is converted into a convex semi-definite optimization problem. After that, the interior point method isadopted to solve and obtain an optimal beam forming matrix and a vector. According to the invention, through the cooperation of the information and the energy, the spectrum and energy insufficient problem can be alleviated to a certain degree, so that the system performance is improved.

A Tx beamforming method for multi-sector cooperative transmission in a multi-antenna system includes determining a transmission mode of sector boundary users according to a channel condition; determining a multi-sector cooperative Tx beam for supporting multiple users, based on the transmission mode of the user; determining a user combination for multi-sector cooperative beamforming by considering the determined multi-sector cooperative Tx beam; and performing sector cooperative Tx beamforming with the determined user combination. Thus, the overall system capacity can be enhanced.

The invention provides an asynchronous random access method based on a multi-satellite cooperative beam forming technology. The asynchronous random access method comprises the steps of time-frequencysynchronization, collision detection, multi-satellite cooperative beam forming and cooperative interference elimination. Aiming at the characteristics of mass connection, strong burstiness and short data packets of services in the satellite Internet of Things, and in combination with the characteristic that the number of visible satellites of a future giant low-orbit satellite constellation is large, the problem that deadlock is likely to occur in a random access system under the high-load condition is relieved; simulation results show that compared with a traditional pure ALOHA, a time slot ALOHA and a multi-satellite cooperative asynchronous random access scheme proposed by a former person, the asynchronous random access method provided by the invention has better throughput performance.

The invention discloses a high-orbit and low-orbit frequency spectrum sharing method based on formation satellite distributed beam forming, which aims at a scene of frequency spectrum sharing between high-orbit and low-orbit satellite communication systems and considers that a GEO satellite communication system primary user and an LEO satellite communication system secondary user share the same frequency in an uplink. A novel frequency spectrum sharing method based on a formation satellite cooperative beam forming technology is provided, the interference problem in a high and low orbit satellite communication system frequency sharing scene is solved from an airspace angle by using a satellite cluster of low orbit formation flight, and the communication performance of a secondary user is ensured; by analyzing same-frequency interference when high and low orbit satellite systems coexist and adopting a self-adaptive beam forming method of a linear constraint minimum variance criterion, the receiving pattern direction of formation satellites is adjusted, so that the main lobe direction of a beam is aligned with a low orbit satellite user communicating with the beam, the null direction is aligned with a GEO ground station, the signal to interference and noise ratio of the low orbit satellite system is improved, and the signal to interference and noise ratio of the formation satellites is improved. And the same-frequency interference between the double satellite systems is relieved from the spatial domain dimension.

A coordinated beamforming method and apparatus based on partial interference alignment, the method includes: selecting an optimal partial interference alignment mode from selectable partial interference alignment modes of terminals covered by base stations in a coordinating cluster of a coordinated multiple points transmission according to a chordal distance criterion; and transmitting, by the base stations, signals to the terminals by adopting the optimal partial interference alignment mode.

The invention discloses a single base station power constraint and rate maximization multipoint cooperation wave beam forming and power distribution method. The method comprises the following steps: firstly, converting sum rate maximization problem into an emission power minimization problem satisfying a minimum rate requirement; secondly, using a second-order cone programming optimization method to solve the emission power minimization problem so as to obtain an emission wave beam vector and emission power; then, taking the obtained wave beam vector as a constant, converting the sum rate maximization optimization problem into the sum rate maximization optimization problem of a single-input single-output communication network, and using a convex approximation method and a geometric programming optimization method to solve the sum rate maximization optimization problem so as to obtain the emission power of the sum rate maximization when the emission wave beam vector is given. Compared to the current sum rate maximization multipoint cooperation wave beam forming method, by using the method of the invention, calculating complexity is low and the sum rate obtained through the method of the invention approximates the optimal sum rate searched by an exhaustive method.

The invention provides a distributed beam forming method based on 2bit feedback. Received signal strength is monitored and disturbance amplitude is selected by using feedback control information fully, thus maximizing the convergence speed of a system. When the RSS (Received Signal Strength) is relatively small, namely when the RSS is far smaller than a demanded value of the system, a disturbance step size is equal to a greater value Lambda1, thus being beneficial for accelerating the convergence speed; when the RSS is increased, namely when the RSS is a little smaller than the demanded value of the system, the disturbance step size is equal to a smaller value Lambda2, thus being beneficial for reducing wrong disturbance times; moreover, when random disturbance is ineffective, a correction factor is updated to the reverse value of random disturbance in a former time slot and is used for correcting a disturbance direction. According to the method, different disturbance step sizes are selected by strengthening monitoring on the RSS; the convergence process is more intelligent; rapid convergence is carried out when the rapid convergence is necessary; the force is enhanced when precise control is necessary; the 2bit feedback algorithm is applicable to various scenes; and the convergence speed of the feedback system is remarkably increased.

The invention discloses an unmanned aerial vehicle relay communication method based on virtual array antenna cooperative beam forming. The method comprises the following steps: 1, determining the number of unmanned aerial vehicle nodes forming an unmanned aerial vehicle antenna array; 2, determining an azimuth angle and an elevation angle according to positions of the unmanned aerial vehicle nodes and a position of a remote base station needing communication; 3, establishing a calculation model of a transmission rate from the unmanned aerial vehicle antenna array to a receiving base station, a calculation model of the maximum sidelobe level of the unmanned aerial vehicle antenna array and a calculation model of energy consumption of a unmanned aerial vehicle, and determining optimal positions of the unmanned aerial vehicle nodes, an optimal base station communicating with the unmanned aerial vehicle antenna array and an optimal excitation current weight by taking the maximum transmission rate from the unmanned aerial vehicle antenna array to the receiving base station, the minimum maximum sidelobe level of the unmanned aerial vehicle antenna array and the minimum energy consumption of the unmanned aerial vehicle as optimization targets; and 4, after the unmanned aerial vehicle nodes move to the optimal positions, forming a virtual antenna array and transmitting data to the optimal base station by utilizing cooperative beam forming.

A device includes circuitry configured to implement one or more PHY communications protocols to simultaneously communicate with one or more stations via communication links on one or more wireless networks, communicate with additional devices via a backhaul network, and exchange collaboration data, including at least one of protocol data or collaborative beamforming data, with the additional devices via the backhaul network to maintain signal parameters of communications signals with the one or more stations.