摘要:
The present invention relates to a method and arrangement for reducing feedback data in a communication system, said communication system comprising a number of transmitter antennas, nτ, and a number of receiver antennas, nR, for parallel spatially independent transmission and reception of signals, wherein a channel response is represented by a matrix (G) containing nR×nτ complex variables. The method comprises the steps of: decomposing an expression of said channel response matrix (G) into products of a unitary transform (V), nR×nT diagonal matrix (Λ) and a conjugate transpose of a unitary matrix (W). Choosing said unitary matrix (W) such that its diagonal elements are real, substituting said channel response matrix (G) with a representative subset of elements in said decomposed expression of said channel response matrix (G), said representative subset comprising diagonal of a first matrix (Λ) and lower triangle of a second matrix (W) excluding the diagonal.
摘要:
Bandwidth is allocated in a radio packet data system by sending achievable data rate estimate information from an access terminal to an access network. The achievable data rate estimate information is associated with scenarios corresponding to state combinations of a plurality of transmitters in the access network in which each transmitter is in either a serving, active, or idle state and one or more of the plurality of transmitters is in the idle state in one or more of the scenarios.
摘要:
The present invention relates to a method and arrangement for reducing feedback data in a communication system, said communication system comprising a number of transmitter antennas, nτ, and a number of receiver antennas, nR, for parallel spatially independent transmission and reception of signals, wherein a channel response is represented by a matrix (G) containing nR×nτ complex variables. The method comprises the steps of: decomposing an expression of said channel response matrix (G) into products of a unitary transform (V), nR×nτ diagonal matrix (Λ) and a conjugate transpose of a unitary matrix (W). Choosing said unitary matrix (W) such that its diagonal elements are real, substituting said channel response matrix (G) with a representative subset of elements in said decomposed expression of said channel response matrix (G), said representative subset comprising diagonal of a first matrix (Λ) and lower triangle of a second matrix (W) excluding the diagonal.
摘要:
A method and apparatus for channel estimation based on extracting channel information, including noise spectral density, from a received signal, and advantageously exploiting that information for improved channel estimation accuracy. One embodiment is directed to a method of generating channel estimates in a wireless communication receiver, for processing a received communication signal. The method includes generating first channel estimates from a set of pilot observations obtained from the received communication signal, using a first channel estimation process that is not dependent on knowledge of channel statistics. The method further includes estimating channel statistics and a noise variance from the first channel estimates, and generating second channel estimates from the set of pilot observations, the estimated channel statistics, and the estimated noise variance, using a second channel estimation process that is dependent on knowledge of the channel statistics.
摘要:
A method and apparatus for channel estimation based on extracting channel information, including noise spectral density, from a received signal, and advantageously exploiting that information for improved channel estimation accuracy. One embodiment is directed to a method of generating channel estimates in a wireless communication receiver, for processing a received communication signal. The method includes generating first channel estimates from a set of pilot observations obtained from the received communication signal, using a first channel estimation process that is not dependent on knowledge of channel statistics. The method further includes estimating channel statistics and a noise variance from the first channel estimates, and generating second channel estimates from the set of pilot observations, the estimated channel statistics, and the estimated noise variance, using a second channel estimation process that is dependent on knowledge of the channel statistics.
摘要:
A wireless communication receiver improves signal impairment correlation estimation in MIMO/MISO systems by considering different transmit power allocations and different transmit antenna power distributions in its impairment correlation calculations. The receiver may be implemented in according to a variety of architectures, including, but not limited to, Successive Interference Cancellation (SIC) Generalized RAKE (G-RAKE), Joint Detection (JD) G-RAKE, and Minimum Mean Squared Error (MMSE) G-RAKE. Regardless of the particular receiver architecture adopted, the improved impairment correlations may be used to calculate improved (RAKE) signal combining weights and/or improve channel quality estimates for reporting by receivers operating in Wideband CDMA (W-CDMA) systems transmitting HSDPA channels via MIMO or MISO transmitters. A transmitter may be configured to facilitate impairment correlation determinations by wireless communication receivers operating in MIMO/MISO environments, by signaling one or more values, e.g., data-to-pilot signal transmit power ratios and/or transmit antenna power distributions for the data and pilot signals.
摘要:
In a wireless network, plural downlink signals from plural base stations are transmitted to a terminal. The plural downlink signals all carry the same information to the terminal. The terminal provides feedback on the downlink channels. The feedback provides information on the taps of the channels. The amount of information fed back is constrained. Based on the feedback, transmission parameters of the downlink signals are adjusted. The process of transmitting, providing feedback, and adjusting the parameters continue so that the energy of the downlink signal is enhanced at the terminal location and suppressed elsewhere. Beam forming can be used to further suppress the energy signature at locations other than the terminal location.
摘要:
A receiver and a method are described herein for reducing an amount of channel state information related to a transmit channel correlation matrix ΦTX that is feedback to a transmitter. In addition, to a transmitter and a method are described herein for reconstructing the transmit channel correlation matrix φTX using the reduced channel state feedback information received from the receiver.
摘要:
In MIMO systems, two or more transmit signals are transmitted from different antenna clusters having one or more transmit antennas each. A precoding circuit weight the transmit signals transmitted from each transmit antenna using a common set of frequency independent antenna weights for all antenna clusters. The antenna weights are computed based on correlations between transmit antennas in the same antenna cluster.
摘要:
A method for determining antenna weights for use in transmitting data from a plurality of base stations to a user device is disclosed. The antenna weights are determined using an input covariance matrix (S), and the input covariance matrix is determined subject to a predetermined power constraint and a predetermined, non-zero interference constraint.