According to one of the aspects, there is provided a method for providing channel state feedback related to a wireless link between a transmitter having multiple transmit antennas and a receiver having at least one receive antenna. The method comprises determining (S1) channel estimates for at least a subset of the effective channels between the transmitter and the receiver, each effective channel including a propagation channel, and signal paths in the transmitter and the receiver. The method also comprises determining (S2) frequency-independent and/or inter-antenna-independent channel state information associated with phase relaxation of at least the subset of the effective channels based on the channel estimates, and generating (S3) channel state feedback including at least a representation of the frequency-independent and/or inter-antenna-independent channel state information associated with the phase relaxation. The method further comprises transmitting (S4) the channel state feedback to the transmitter.

Apparatuses, methods, and systems for beamforming to multiple users using switched passive time-delay structures are disclosed. One method includes an input switch that receives a plurality of input signals for transmission. Further, the apparatus includes a plurality of passive time-delay structures, wherein the input switch selectively connects the plurality of input signals to at least one of the plurality of passive time-delay structures, and wherein each of the passive time-delay structures is preconfigured to provide a plurality of delayed signals wherein each of the plurality of delayed signals is a delayed version of a one of the plurality of input signals. The apparatus further includes an antenna array, wherein the antenna array receives the plurality of delayed signals of the passive time-delay structures, and generates a beamforming pattern corresponding with a selected one of the passive time-delay structures.

A method and system are provided for scheduling data transmission in a Multiple-Input Multiple-Output (MIMO) system. The MIMO system may comprise at least one MIMO transmitter and at least one MIMO receiver. Feedback from one or more receivers may be used by a transmitter to improve quality, capacity, and scheduling in MIMO communication systems. The method may include generating or receiving information pertaining to a MIMO channel metric and information pertaining to a Channel Quality Indicator (CQI) in respect of a transmitted signal; and sending a next transmission to a receiver using a MIMO mode selected in accordance with the information pertaining to the MIMO channel metric, and an adaptive coding and modulation selected in accordance with the information pertaining to the CQI.

Aspects of the present invention provide additional MAC functionality to support the PHY features of a wireless communication system framework. The additional MAC functionality aids in enabling feedback from wireless terminals to base stations. In some aspects of the invention the feedback is provided on an allocated feedback channel. In other aspects of the invention the feedback is provided by MAC protocol data units (PDU) in a header, mini-header, or subheader. The feedback may be transmitted from the wireless terminal to the base station autonomously by the wireless terminal or in response to an indication from the base station that feedback is requested. Aspects of the invention also provide for allocating feedback resources to form a dedicated feedback channel. One or more of these enhancements is included in a given implementation. Base stations and wireless terminals are also described upon which methods described herein can be implemented.

A method and system are provided for scheduling data transmission in a Multiple-Input Multiple-Output (MIMO) system. The MIMO system may comprise at least one MIMO transmitter and at least one MIMO receiver. Feedback from one or more receivers may be used by a transmitter to improve quality, capacity, and scheduling in MIMO communication systems. The method may include generating or receiving information pertaining to a MIMO channel metric and information pertaining to a Channel Quality Indicator (CQI) in respect of a transmitted signal; and sending a next transmission to a receiver using a MIMO mode selected in accordance with the information pertaining to the MIMO channel metric, and an adaptive coding and modulation selected in accordance with the information pertaining to the CQI.

Aspects of the present invention provide additional MAC functionality to support the PHY features of a wireless communication system framework. The additional MAC functionality aids in enabling feedback from wireless terminals to base stations. In some aspects of the invention the feedback is provided on an allocated feedback channel. In other aspects of the invention the feedback is provided by MAC protocol data units (PDU) in a header, mini-header, or subheader. The feedback may be transmitted from the wireless terminal to the base station autonomously by the wireless terminal or in response to an indication from the base station that feedback is requested. Aspects of the invention also provide for allocating feedback resources to form a dedicated feedback channel. One or more of these enhancements is included in a given implementation. Base stations and wireless terminals are also described upon which methods described herein can be implemented.

Apparatuses, methods, and systems for processing beamforming signals of a passive time-delay structure are disclosed. One apparatus includes a node that includes baseband processing circuitry that is operative to receive and processes transmission signals, a passive time-delay structure that is preconfigured to generate a plurality of output signal, an antenna array, wherein the antenna array is operative to receive and transmit the plurality of output signals of the passive time-delay structure, wherein delays of the passive time-delay structure provide for the formation of a beamforming pattern by the transmitted plurality of output signals, and a controller. The controller is operative to determine a characterization of the beamforming pattern. The baseband processing circuitry operates to process the transmission signals based at least in part on the characterization of the beamforming pattern, and the node transmits the processed transmission signals to the one or more transceivers.

A method for measuring and feeding back channel information and a corresponding apparatus are provided. In an embodiment the method includes determining, by a first network device, a first codebook from a first codebook set, wherein the first codebook set comprises at least two first codebooks, wherein a sub-vector W.sub.x of each first codebook is formed by a zero vector and a non-zero vector, wherein vectors forming the W.sub.x are associated with different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector $\left[\begin{array}{c}{V}_a^0\\ 0\\ V_a^1\\ 0\end{array}\right]$
and/or at least one second sub-vector $\left[\begin{array}{c}0\\ V_b^0\\ 0\\ V_b^1\end{array}\right],$
and wherein V.sub.a.sup.0 and V.sub.a.sup.1 are elements in the vector V.sub.a, and V.sub.b.sup.0 and V.sub.b.sup.1 are elements in the vector V.sub.b and sending a codebook index to a second network device, wherein the codebook index is associated with the first codebook selected from the first codebook set.

Techniques described herein describe aspects of signal adjustments in user equipment-coordination set, UECS, joint transmissions. A base station analyzes a first joint transmission from multiple user equipments, UEs, participating in a UECS, where the multiple UEs include a coordinating UE of the UECS and at least one non-coordinating UE participating in the UECS. The base station determines that the first joint transmission fails to meet a performance metric and directs the multiple UEs participating in the UECS to add signal adjustments to a second joint transmission.

Certain aspects of the present disclosure provide various techniques for beam recovery. For example, a method for wireless communication by a network entity may include providing configuration information to a user equipment (UE) indicating a sequence of target beams and timing information to try each target beam in the sequence, and attempting to communicate with the UE using one or more of the target beams according to the timing information, in response to a beam failure.