Techniques are described for carrier frequency offset (CFO) and channel estimation of orthogonal frequency division multiplexing (OFDM) transmissions over multiple-input multiple-output (MIMO) frequency-selective fading channels. A wireless transmitter forms blocks of symbols by inserting training symbols within two or more blocks of information-bearing symbols. The transmitter applies a hopping code to each of the blocks of symbols to insert a null subcarrier at a different position within each of the blocks of symbols, and a modulator outputs a wireless signal in accordance with the blocks of symbols. A receiver receives the wireless signal and estimates the CFO, and outputs a stream of estimated symbols based on the estimated CFO.

Channel state information (CSI) feedback in a wireless communication system is disclosed. A precoding matrix is generated for multi-antenna transmission based on precoding matrix indicator (PMI) feedback, wherein the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first codebook and a second codebook. In one embodiment, the first codebook comprises at least a first precoding matrix constructed with a first group of adjacent Discrete-Fourier-Transform (DFT) vectors. In another embodiment, the first codebook comprises at least a second precoding matrix constructed with a second group of uniformly distributed non-adjacent DFT vectors. In yet another embodiment, the first codebook comprises at least a first precoding matrix and a second precoding matrix, where said first precoding matrix is constructed with a first group of adjacent DFT vectors, and said second precoding matrix is constructed with a second group of uniformly distributed non-adjacent DFT vectors.

A wireless device may support a plurality of channel state information (CSI) processes. The wireless device may send an indication of a number of supported CSI processes to a first base station. The first base station may send to the wireless device a handover command, instructing the wireless device to handover to a second base station. The handover command may comprise configuration parameters for CSI processes associated with the second base station. The configuration parameters may be based on the number of CSI processes supported by the wireless device.

Embodiments of the present disclosure relate to a device, method, apparatus and computer readable storage medium for channel estimation in a multiple input multiple output (MIMO) system. The MIMO system comprises a receiver configured with a plurality of receiving antennas and a transmitter configured with a plurality of transmitting antennas. In example embodiments, a plurality of data symbols are detected based on channel estimation from a plurality of signals received by the plurality of receiving antenna from the plurality of transmitting antennas. The plurality of detected data symbols are adjusted based on a set of constellation points for a modulation mode used by the transmitter and associated with the plurality of signals. The channel estimation is updated based on the plurality of adjusted data symbols.

An electronic device is provided. The electronic device includes: a panel, a first support component, and a second support component. The panel includes a bottom surface, a first corner and a second corner, and the bottom surface is connected between the first corner and the second corner. The first support component includes a first side portion that supports the first corner of the panel. The first side portion has a first length and a first Young's modulus. The second support component includes a second side portion that supports the second corner of the panel. The second side portion has a second length and a second Young's modulus. The first length and the second length satisfy the following inequalities: $10\times \sqrt{\frac{W}{2k1\times \tan 1^{°}}}\le L1<\frac{P}{2},\mathrm{and}$

A system comprising a plurality of nodes communicatively coupled to one another via at least one wireless link and a controller communicatively coupled to at least one of the nodes, wherein the controller (1) coordinates at least one scan that measures interference introduced into the wireless link, (2) identifies, based at least in part on the scan, one or more characteristics of the wireless link, (3) determines, based at least in part on the characteristics of the wireless link, that the node is eligible for a tapered codebook that, when implemented, modifies at least one feature of an antenna array that supports the wireless link in connection with the node, and then (4) directs the node to implement the tapered codebook. Various other apparatuses, systems, and methods are also disclosed.

Methods, apparatus, and systems for wireless communications are disclosed. A first base station may receive one or more message from a second base station. The messages may include downlink beamforming information elements for a downlink cell. Each downlink beamforming information element may be associated with a respective group of resource blocks of a plurality of groups of resource blocks in the downlink cell. The first base station may select a first beamforming codeword for at least one group of resource blocks of the plurality of groups of resource blocks based on the downlink beamforming information associated with the at least one group of resource blocks. The first base station may transmit, to a wireless device, signals on the at least one group of resource blocks employing the first beamforming codeword.

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.

This document discloses a reflector antenna system with movable MIMO multiple feeds and adaptive field focusing method for wireless communication in multipath fading environment; the system comprises antenna reflector, multiple feeds, the equal number of the signal receiving channels and signal transmitting channels to the feeds, all the channels are capable to measure and adjust the amplitude and time delay of signals, and the method for amplitude and time delay adjustment of the powered signals. In signal receiving mode the antenna system makes the signal components arrived through unknown multipath superimpose synchronously; in signal transmitting mode, the system let the wave components radiated from different transmitting channels superimpose synchronously, realizing adaptive field focusing at the antenna of the communication target. This antenna system is suitable for point to point wireless communication in wireless propagation environment with multipath fading effect, showing remarkable improvement of SNR of the signals transmitted and received.

Systems for mitigating interference in a massive MIMO wireless network include an access node, a plurality of antennae communicatively coupled to the access node, and a processor communicatively coupled to the access node. The processor can be configured to perform operations including communicating with one or more wireless devices within a wireless sector utilizing one or more antennae from the plurality of antennae, and monitoring an interference level within the wireless sector. Upon the interference level meeting a threshold, the processor may be configured to utilize fewer antennae to communicate with the one or more wireless devices. Conversely, upon the interference level not meeting the threshold, the processor may be configured to utilize more antennae to communicate with the one or more wireless devices.