System and method for spatial multiplexing for coordinated multi-point transmission
First Claim
1. A method for communications device operations, the method comprising:
- receiving transmissions from at least two access points;
measuring channels between the communications device and each of the at least two access points in accordance with the received transmissions;
computing beamforming weights in accordance with the measured channels, wherein the computing is in accordance with attempting to maximize a capacity of a communications system containing the communications device and the at least two access points with the beamforming weights, and wherein the attempting to maximize the capacity comprises computing a value of a cost function in accordance with the measured channels and the beamforming weights, and determining a convergence of the value of the cost function;
transmitting the beamforming weights to the at least two access points; and
receiving coordinated multi-point (CoMP) transmissions from the at least two access points, wherein each of the (CoMP) transmissions is beamformed using one of the beamforming weights, and wherein the at least two access points comprises first and second access points, each having two transmit antennas, wherein the communications device includes two antennas, and wherein computing beamforming weights comprises determining w1 and w2 such that a capacity function expressible as
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Abstract
A system and method for spatial multiplexing for coordinated multi-point transmission are provided. A method for communications device operations includes receiving transmissions from at least two access points, measuring channels between the communications device and each of the at least two access points based on the received transmissions, computing beamforming weights based on the measured channels, and transmitting the beamforming weights to the at least two access points. The computing is based on attempting to maximize a capacity of a communications system containing the communications device and the at least two access points with the beamforming weights, and the beamforming weights are used at the at least two access points to beamform transmissions to the communications device using coordinated multi-point transmission.
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Citations
20 Claims
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1. A method for communications device operations, the method comprising:
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receiving transmissions from at least two access points; measuring channels between the communications device and each of the at least two access points in accordance with the received transmissions; computing beamforming weights in accordance with the measured channels, wherein the computing is in accordance with attempting to maximize a capacity of a communications system containing the communications device and the at least two access points with the beamforming weights, and wherein the attempting to maximize the capacity comprises computing a value of a cost function in accordance with the measured channels and the beamforming weights, and determining a convergence of the value of the cost function; transmitting the beamforming weights to the at least two access points; and receiving coordinated multi-point (CoMP) transmissions from the at least two access points, wherein each of the (CoMP) transmissions is beamformed using one of the beamforming weights, and wherein the at least two access points comprises first and second access points, each having two transmit antennas, wherein the communications device includes two antennas, and wherein computing beamforming weights comprises determining w1 and w2 such that a capacity function expressible as - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for operations at a first access point, the method comprising:
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transmitting a pilot signal; receiving beamforming weights from a communications device served by the first access point, wherein the first access point and at least one additional access point is transmitting to the communications device using coordinated multi-point transmission over channels measured by the communications device, wherein the beamforming weights are used to beamform transmissions to the communications device, the beamforming weights having been computed at the communications device in accordance with the measured channels and in accordance with an attempt to maximize a capacity of a communications system containing the communications device, the first access point, and the at least one additional access point, wherein the attempt to maximize the capacity includes computing a value of a cost function in accordance with the measured channels and the beamforming weights, and determining a convergence of the value of the cost function; beamforming a transmission with the beamforming weights; and transmitting the beamformed transmission to the communications device, wherein the at least one additional access point comprises a second access point, wherein the first and second access points each has two transmit antennas, wherein the communications device includes two antennas, and wherein the beamforming weights comprise w1 and w2 such that a capacity function expressible as - View Dependent Claims (15, 16, 17)
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18. A communications device comprising:
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a receiver to be coupled to a receive antenna in order to receive signals detected by the receive antenna; a transmitter to be coupled to a transmit antenna in order to transmit signals with the transmit antenna; and a controller coupled to the receiver and to the transmitter, the controller configured to measure a channel between the communications device and an access point of a plurality of access points transmitting to the communications device, and to compute beamforming weights for use by the plurality of access points transmitting to the communications device in coordinated multi-point transmissions, wherein the controller computes the beamforming weights in accordance with attempting to maximize a capacity of a communications system containing the communications device and the access points, wherein the controller comprises a measure channel unit configured to measure channels between the communications device and each access point in the plurality of access points in accordance with transmissions made by each access point; and a beamforming weights compute unit coupled to the measure channel unit and configured to iteratively compute values of the beamforming weights in accordance with the channel measurements, to compute a value of a cost function in accordance with the channel measurements and the beamforming weights, and to determine a convergence of the value of the cost function, and wherein the plurality of access points comprises first and second access points, each having two transmit antennas, wherein the communications device includes two antennas, and wherein the beamforming weights compute unit configured to compute the values of the beamforming weights comprises the beamforming weights compute unit configured to determine w1 and w2 such that a capacity function expressible as - View Dependent Claims (19, 20)
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Specification