Abstract: A radio communication sent by a transmitter having M transmit antennas is received by a receiver having N receive antennas, where M is a positive integer greater than or equal to one and N is positive integer greater than one. Thus, N output signals, one for each receive antenna, are received. The signal transmitted from each transmit antenna includes predetermined pilot symbols known by the receiver and information symbols to be determined by the receiver. Weights for estimating each of M×N single-input/single-output channels between transmit and receive antennas are determined based on jointly processing pilot symbols received on all of the N receive antennas. The M×N channels are estimated based on the determined weights, and those estimated channels are used to determine the information symbols. An iterative procedure is used to estimate the M×N channels using a noise correlation matrix estimate and to estimate the noise correlation matrix using the M×N channel estimates.

Abstract: Pre-coder techniques disclosed herein are based on long-term statistical channel information for reducing channel feedback overhead and transmitter complexity. In an embodiment, a receiver includes two or more receive antennas spaced approximately ?/2 apart and a baseband processor. The baseband processor computes channel correlations for different combinations of transmit antennas and each receive antenna and averages the channel correlations over the different receive antennas to form a frequency-independent channel correlation matrix. The baseband processor also computes a scalar representing noise variance at the receive antennas and feeds back the frequency-independent channel correlation matrix and the scalar for use in performing transmitter pre-coding computations.

Abstract: A method of supplying channel information in a wireless communication system comprises a mobile terminal normally providing a basic channel report to the wireless communication system; the mobile terminal receiving at least one common feedback criterion broadcast to a plurality of mobile terminals; the mobile terminal determining if the mobile terminal satisfies a condition based on the at least one common feedback criterion; and the mobile terminal selectively providing an enhanced channel report to the wireless communication system based on the determining. The basic channel report may comprise information related to a first set of channel parameters, and the enhanced channel report may provide greater detail on the first set of channel parameters and/or relate to a second set of channel parameters. A method of a base station adaptively controlling channel information reporting by broadcast transmitting at least one common feedback criterion is also presented.

Abstract: A base station schedules one of a plurality of mobile terminals based on an expected SIR of an effective traffic channel associated with a non-scheduled mobile terminal. The expected SIR is generated by computing the expected SIR of a hypothesized traffic channel with a pre-filter adapted to the non-scheduled mobile terminal that would result if the non-scheduled mobile terminal was scheduled. A base station then schedules transmissions to the plurality of mobile terminals based on the computed expected SIR. The expected SIR may be computed so as to compensate for mismatch between the hypothesized traffic channel and a pilot channel associated with the non-scheduled mobile terminal. Alternatively, the expected SIR may be directly computed based on an estimate of the pre-filter of the hypothesized traffic channel.

Abstract: 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, n?, 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×n? 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×n? diagonal matrix (?) 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 (?) and lower triangle of a second matrix (W) excluding the diagonal.

Abstract: According to one or more method and apparatus embodiments taught herein, network base stations reduce temporal variations in the interference perceived by mobile stations operating within the network by slowing down the rate at which they change or otherwise update the linear precoding settings applied to their transmitted Orthogonal Frequency Division Multiplex (OFDM) signals in comparison to the rate at which the base stations perform link adaptation. That is, the precoding-related component of measured interference (e.g., other-cell interference) at the mobile stations is made quasi-stationary with respect to channel quality reporting and link adaptation intervals by fixing the preceding settings used by each base station over time intervals substantially longer than the channel reporting/link adaptation intervals.

Abstract: A method of variable rate vector quantization reduces the amount of channel state feedback. Channel coefficients of a communication channel are determined and second order statistics (e.g., variances) of the channel taps are computed). Bit allocation for the channel taps are determined based on the coefficients statistics. The channel taps are individually quantized at rates determined based on said bit allocations.

Abstract: 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.

Abstract: Diversity radio transmission is accomplished with excellent performance using multiple antennas receiving a transmission signal from a single power amplifier. A data signal to be transmitted is provided to a first antenna, and a phase-shifted version of the data signal is applied a second antenna. The relative phase shift between the data signal transmitted over the two transmit antennas ensures the two antenna signals can be constructively combined at the receiver. In one non-limiting example embodiment, the relative phase shift is determined by processing pilot signals sent along with the data signal and which are transmitted with predetermined phase shifts.

Abstract: Multi-antenna transmission control presented herein involves generating a set of virtual channel realizations at the transmitter that shares the same second-order statistics as the actual channel realizations observed for a targeted receiver. By making the control-related quantities of interest at the transmitter depend on the long-term statistics of the channel, the actual channel realizations are not needed for transmission control, e.g., for accurate Multiple-Input-Multiple-Output (MIMO) preceding. As such, the use of virtual channel realizations enables transmission control that approaches the “closed-loop” channel capacity that would be provided by full feedback of the (instantaneous) actual channel realizations, without requiring the overhead signaling burden that attends full feedback.

Abstract: A base station maximizes a uplink data transmission rate from multiple mobiles treated by the base station as a virtual single uplink transmitter. The base station identifies a set of mobile stations as a candidate transmitting set and determines a transmit power allowable from the mobile stations in the candidate transmitting set. A subset of those mobile stations in the candidate transmitting set is identified. Uplink data transmission rates are assigned and communicated to the subset of mobile stations in the candidate transmitting set so as to optimize a total number of bits processed by the base station associated with the uplink transmissions received from the subset of candidate mobile stations. The optimization may accomplish one or more objectives in addition to optimizing the total number of bits processed.

Abstract: A method is described herein for reducing the number of feedback bits needed to send channel state information over a feedback channel from a receiving unit (e.g., mobile terminal, base station) to a transmitter unit (e.g., base station, mobile terminal) in a wireless communication system.

Abstract: A receiver includes a receiver circuit that decodes multiple signals of interest contained in a composite received signal. The receiver comprises a plurality of successive signal detection stages to detect respective signals contained in the composite received signal. Each detection circuit comprises at least one Generalized RAKE combining circuit and generates a detected signal at an output. Each but the last stage further comprises a signal regeneration circuit that cancels the signal of interest detected by that stage from a stage input signal provided to the next stage such that successive detection of the signals of interest benefits from cumulative cancellation of the previously detected signals.

Abstract: 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.

Abstract: A method and apparatus for generating channel quality information, such as may be used for transmit link adaptation, provide different operating modes, such as a first mode that may be used when propagation channel estimates are not reliable, and a second mode that may be used when the propagation channel estimates are reliable. In one or more embodiments, channel quality information is generated using receiver performance information that characterizes receiver performance in terms of a defined channel quality metric, e.g., supported data rates, for different values of receiver input signal quality over a range of propagation channel realizations.

Abstract: A control channel for MIMO users operating in conjunction with an HS-DSCH system shares channelization codes with an HS-SCCH control channel. MIMO control channel information can be signaled from a transmit antenna selected based on information produced by the intended recipient. The modulation format used by a MIMO control channel can be selected based on the number of antenna streams in the corresponding MIMO data transmission.

Abstract: A mobile phone is described herein that has control (or at least partial control) over which virtual antenna(s) in one or more base stations should be used for transmissions. In one embodiment, the mobile phone performs the following steps: (1) receives an antenna subset list (from the scheduling unit) which identifies a configuration of virtual antennas that is associated with the base station(s); (2) uses the antenna subset list to select which virtual antenna(s) in the configuration of virtual antennas should be used for transmissions; and (3) sends an antenna selection signal (to the scheduling unit) which contains information that instructs/requests the base station(s)/scheduling unit to use the selected virtual antenna(s) for transmissions.

Abstract: Processing of loop-back information returned by one or more mobile stations that are served by a wireless communication network permits the network to compensate its transmit signals for increased transmission efficiency and reduced signal interference at the mobile stations. Generally, the network forms one or more transmit signals as a combination of different signals intended for the different mobile stations, and remembers transmit information associated with these transmit signals. The mobile stations return loop-back signals to the network, which determines transmit signal compensation information by comparing loop-back information to memorized information. The mobile stations may loop-back samples from composite received signals, from processed received signal samples, or loop-back estimates.

Abstract: A receiver reduces interference in a received symbol of interest attributable to an interfering symbol using knowledge of the symbol spreading codes. The receiver comprises a plurality of correlators generating despread values for the received symbol of interest and the interfering symbol, and a combiner to combine the despread values using combining weights calculated based on spreading code correlations between spreading codes for the received symbol of interest and the interfering symbol.

Abstract: 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.