Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit an indication of support for selectively using transmission diversity for communicating. The UE may transmit one or more communications selectively using transmission diversity. Numerous other aspects are described.

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.

A test transmission can be used to train and/or select a signal. For example, a cellular network can configure a receiver with a recommended receiver signal sweeping pattern for mobile devices. A transmitter device can duplicate a data packet transmission and send it to a receiver device to ensure that the receiver can receive the duplicated packets from different signals. Consequently, the duplicated data packet can be indicated in the associated control channel so that the receiver is aware that the data packet is a duplicated transmission, and based on this info and configuration data, the receiver can select a more favorable signal.

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 wireless communication system includes a wireless transmit/receive unit (WTRU). The WTRU is configured to generate at least one local codebook based on a baseline codebook, and select a codeword from the local codebook that is associated with feedback.

A device includes a wireless interface configured for wirelessly transmitting a signal to a receiver; and a precoder unit configured for obtaining a first data signal to be transmitted and a second data signal to be transmitted; and for performing a first multipath-precoding of the first data signal according to a first set of paths between the device and the receiver to obtain a first precoded signal; and for performing a second multipath-precoding of the second data signal according to a second set of paths between the device and the receiver to obtain and a second precoded signal; wherein the precoder unit is configured for generating the first precoded signal and the second precoded signal such that the second precoded signal is delayed with respect to the first precoded signal at the receiver. The device is configured for transmitting the first precoded signal and the second precoded signal.

Systems and methods for closed loop MIMO (multiple input and multiple output) wireless communication are provided. Various transmit formats including spatial multiplexing and STTD are defined in which vector or matrix weighting is employed using information fed back from receivers. The feedback information may include channel matrix or SVD-based feedback.

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.

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.

A test transmission can be used to train and/or select a signal. For example, a cellular network can configure a receiver with a recommended receiver signal sweeping pattern for mobile devices. A transmitter device can duplicate a data packet transmission and send it to a receiver device to ensure that the receiver can receive the duplicated packets from different signals. Consequently, the duplicated data packet can be indicated in the associated control channel so that the receiver is aware that the data packet is a duplicated transmission, and based on this info and configuration data, the receiver can select a more favorable signal.