An enhanced linear combination codebook framework can support power allocation between transmission layers. Scaling between the layers of the codebook can be unequal so that power allocated between the layers can depend on the channel. For example, the network can configure the codebook to use radio resource control signaling to send codebook data to the UE.

Precoding is a technique that may be used in wireless communications when antenna spacing in a multiple-input multiple-output (MIMO) system is smaller than optimum spacing conditions. A precoding system and method are disclosed herein that distributes power among streams to trade-off increased data throughput and complexity of interference cancellation. Distributing power among streams may increase data throughput compared to singular value decomposition (SVD) precoding, but interference may be reduced compared to other methods that result in relatively high interference.

Precoding is a technique that may be used in wireless communications when antenna spacing in a multiple-input multiple-output (MIMO) system is smaller than optimum spacing conditions. A precoding system and method are disclosed herein that distributes power among streams to trade-off increased data throughput and complexity of interference cancellation. Distributing power among streams may increase data throughput compared to singular value decomposition (SVD) precoding, but interference may be reduced compared to other methods that result in relatively high interference.

A communication device for providing an explicit channel state information, CSI, feedback in a wireless communication system includes a transceiver to receive, from a transmitter a radio signal via a radio time-variant frequency MIMO channel, the radio signal including downlink reference signals according to a reference signal configuration, and downlink signals including the reference signal configuration, and a processor. The processor estimates the CSI using measurements on the downlink reference signals of the radio channel according to the reference signal configuration over one or more time instants/slots, constructs a frequency-domain channel tensor using the CSI estimate, performs a higher-order principal component analysis, HO-PCA, on the channel tensor, identifies a plurality of dominant principal components of the channel tensor, thereby obtaining a compressed channel tensor, and reports to the transmitter the explicit CSI including the dominant principal components of the channel tensor.

An enhanced linear combination codebook framework can support power allocation between transmission layers. Scaling between the layers of the codebook can be unequal so that power allocated between the layers can depend on the channel. For example, the network can configure the codebook to use radio resource control signaling to send codebook data to the UE.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Methods and systems for sensing a physiological characteristic of a subject. At least one receiver antenna can be provided in proximity to a portion of the subject's body to obtain at least one receiver signal resulting from at least one transmitter signal that has propagated to the receiver antenna and has been reflected, diffracted, scattered, or transmitted by or through the portion of the subject's body. One or more coherent signal pairs can be formed. Then, amplitude and phase information of a plurality of frequency components for each signal pair can be determined. A set of comparison values can be determined for each signal pair by comparing respective frequency component phases and respective frequency component amplitudes of the signals. Physiological characteristics of the subject can then be determined from these comparison values.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

A system and method are described which enable planned evolution and obsolescence of multiuser wireless spectrum. One embodiment of such a system includes one or multiple centralized processors and one or multiple distributed nodes that communicate via wireline or wireless connections. The distributed nodes may share their identification number and other reconfigurable system parameters with the centralized processor. The information about all distributed nodes may be stored in a database that is shared by all centralized processors. The reconfigurable system parameters may comprise power emission, frequency band, modulation/coding scheme. The distributed nodes may be software defined radios such as FPGA, DSP, GPU and/or GPCPU that run algorithms for baseband signal processing and may be reconfigured remotely by the centralized processor. A cloud wireless system may be used wherein the distributed nodes are reconfigured periodically or instantly to adjust to the evolving wireless architecture.

According to the present disclosure, there are provided methods and devices for estimating a high-dimensional MIMO channel by expressing the MIMO channel in the form of a flow function to determine a change from an input state to an output state. This may be considered similar to a manner in which fluid dynamic problems are solved. Instead of using linearization to estimate all of the coefficients of a matrix representing a MIMO channel, a receiver may determine the MIMO channel rank by detecting leading modes in a subspace of the entire MIMO channel matrix.