The present disclosure relates to methods and devices for mitigating inter-cluster interference in clusters where one or more network nodes are transmitting in coordination using several transceiver antennas. In particular the disclosure relates to improved precoder algorithms to be used for coordinated multipoint transmission applications. The disclosure also relates to corresponding computer programs. The disclosure proposes a method, performed in a communication system, of mitigating inter-cluster interference, wherein the communication system is configured to coordinate transmissions of one or more wireless devices within two or more wireless device categories and one or more network nodes, wherein the one or more network nodes are transmitting in coordination to the wireless devices in the cluster using several transceiver antennas.

Various embodiments disclosed herein provide for a reciprocity based channel state information acquisition scheme for frequency division duplex wireless communications systems. By converting channel state information from a traditional frequency-time domain to a Delay-Doppler domain, the channel state information feedback overhead can be reduced since the multi-path of radio propagation is reciprocal in terms of each ray and each cluster of antenna elements. Since the surrounding objects create the same multipath fading for both uplink and downlink transmissions, modeling the channel state information in the Delay-Doppler domain, and adjusting the sign of the Doppler value (negative/positive) can account for the multipath characteristics in both uplink and downlink.

A beamformee device includes a channel estimator, first and second beamforming matrix providers and a dimension reduction unit. The channel estimator receives a NDP through a channel, and obtains channel information of the channel based on the NDP. The first beamforming matrix provider provides wideband beamforming matrices based on the channel information. The dimension reduction unit generates equivalent channel information based on the wideband beamforming matrices. The second beamforming matrix provider provides beamforming matrices based on the equivalent channel information. The wideband beamforming matrices and the subcarrier beamforming matrices are fed back to the beamformer device. Any one or any combination of the plurality of wideband beamforming matrices and the plurality of subcarrier beamforming matrices are selected from codebooks.

Aspects of the subject disclosure may include, for example, determining a coherence block for each user equipment (UE) of a plurality of UEs being served by the first cell, resulting in a plurality of coherence blocks, responsive to the determining, identifying a smallest coherence block from the plurality of coherence blocks, identifying a pilot sequence length based on the smallest coherence block, determining a plurality of orthogonal pilot sequences based on the identifying the pilot sequence length, designating, from the plurality of orthogonal pilot sequences, a first group of orthogonal pilot sequences for use in the first cell, and distributing, to each neighboring cell of a plurality of neighboring cells adjacent to the first cell, a respective group of orthogonal pilot sequences from a remainder of the plurality of orthogonal pilot sequences, to prevent pilot contamination between the first cell and the plurality of neighboring cells. Other embodiments are disclosed.

Aspects of the subject disclosure may include, for example, identifying a coherence time for a user equipment (UE), identifying a coherence bandwidth for the UE, determining a coherence block based on the coherence time and the coherence bandwidth, and, based on a first determination that the coherence block satisfies a threshold, permitting the UE to transmit sounding reference signal (SRS) data over a smaller SRS bandwidth that is smaller than a default SRS bandwidth, at a lower periodicity that is lower than a default periodicity, or a combination thereof, thereby conserving power resources of the UE. Other embodiments are disclosed.

Methods and apparatuses for a channel estimation and prediction operation in a wireless communication systems. A method of a BS comprises: receiving an SRS; partitioning, based on a partition policy, a frequency band of the SRS into sub-bandwidths in a frequency domain; generating, based on previously stored CSI in memory and the partition policy, a set of chunks corresponding to respective sub-bandwidths; performing CHPD operations corresponding to the respective sub-bandwidths to generate channel parameters, wherein different CHPD operations are applied to the respective sub-bandwidths; combining the channel parameters predicted from the respective sub-bandwidths in the frequency domain; and performing, based on the combined channel parameters, a channel estimation and prediction operation.

Multi-stage distributed beamforming for distributed mosaic wireless networks is provided. Embodiments described herein present systems, devices, and methods that provide increased range, data rate, and robustness to interference and jamming. A distributed mosaic wireless network includes a transmitter, a receiver, and one or more distributed clusters of radios referred to herein as mosaics or relay mosaics. Each mosaic consists of several distributed, cooperative radio transceivers (e.g., mosaic nodes) that relay a signal sent by the transmitter towards the receiver. In some embodiments, a single-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to the receiver. In some embodiments, a multi-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to a second mosaic, which then relays this signal by beamforming to the receiver.

A communication device and methods for computing a noise covariance matrix by using unused resources as determined from a first information. The methods and devices are configured to demodulate and decode the first information; determine one or more resource elements during which data is not transmitted to the communication device based on the first information; obtain samples for the one or more determined resource elements; and compute a noise covariance matrix based on the obtained samples.

A beamformee device includes a channel estimator, first and second beamforming matrix providers and a dimension reduction unit. The channel estimator receives a NDP through a channel, and obtains channel information of the channel based on the NDP. The first beamforming matrix provider provides wideband beamforming matrices based on the channel information. The dimension reduction unit generates equivalent channel information based on the wideband beamforming matrices. The second beamforming matrix provider provides beamforming matrices based on the equivalent channel information. The wideband beamforming matrices and the subcarrier beamforming matrices are fed back to the beamformer device. Any one or any combination of the plurality of wideband beamforming matrices and the plurality of subcarrier beamforming matrices are selected from codebooks.

Methods, systems, and devices for wireless communications are described. A communication device, such as a user equipment (UE) and a base station, for example, an eNodeB (eNB), a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) may support techniques for transformation of analog beamforming codebooks. The communication device may modify an analog beamforming codebook based on a covariance matrix associated with interference and noise in a wireless communication system. For example, the communication device may rotate the analog beamforming codebook based on the estimated covariance matrix, or scale one or more beam weights associated with the analog beamforming codebook based on the estimated covariance matrix, or both. The communication device may thereby perform wireless communication with another communication device in the wireless communication system using the modified analog beamforming codebook.