It is provided a method, including decomposing a channel matrix obtained from a reception channel from a sender to a reception antenna array into its singular vectors, wherein the singular vectors include left-singular vectors and right-singular vectors; allocating powers to the right-singular vectors to obtain power-allocated right-singular vectors; identifying maximum antenna gain directions based on a response function of the reception antenna array and all or a subset of the power-allocated right-singular vectors; calculating, for each of the maximum antenna gain directions or a subset thereof, a respective transmission beamforming vector based on a response function of a transmission antenna array; applying the transmission beamforming vectors or a subset thereof to a transmission via the transmission antenna array to the sender.

Embodiments of the disclosure relate to selective multichannel amplification in a distributed communication system. In this regard, a remote antenna unit (RAU) in the distributed communication system receives downlink digital signals associated with downlink channels having respective downlink channel bandwidths. The RAU digitally scales the downlink digital signals based on respective digital scaling factors to generate scaled downlink digital signals having a substantially equal channel power density in the downlink channels. By digitally scaling the downlink digital signals to provide the substantially equal channel power density in the downlink channels, it is possible to provide substantially uniform radio frequency (RF) coverage range across the downlink channels, thus helping to improve overall RF coverage and user experience in a coverage area of the distributed communication system.

In a closed-loop wireless communication system, a codebook-based feedback mechanism is provided to enable non-unitary precoding for multi-stream transmission, where in each stream is optimized with suitable transmission power allocation and AMC. The codebook-based feedback mechanism uses a precoding codebook having a power allocation matrix which is constrained to specify that beamforming always applies full power to a predetermined beam. With this constraint, a one-bit power allocation feedback index may be used to switch between beamforming and spatial multiplexing.

The method comprises receiving periodic CSI feedback configuration information including a periodicity value and an offset value corresponding to a first CSI report, and at least one periodicity value and at least one offset value corresponding to a second CSI report, measuring a first CSI reference signal (CSI-RS) and a second CSI-RS configured for a periodic CSI reporting based on at least two different enhanced MIMO types (eMIMO-Types), generating the first CSI report and the second CSI report for the first eMIMO-Type and the second eMIMO-Type, respectively, determining a periodic reporting interval for each of the first CSI report and the second CSI report, and reporting the first and second CSI reports based on the determined periodic reporting intervals using a physical uplink control channel (PUCCH) format 2 or a PUCCH format 3 or a combination of the PUCCH format 2 and the PUCCH format 3.

The method comprises receiving periodic CSI feedback configuration information including a periodicity value and an offset value corresponding to a first CSI report, and at least one periodicity value and at least one offset value corresponding to a second CSI report, measuring a first CSI reference signal (CSI-RS) and a second CSI-RS configured for a periodic CSI reporting based on at least two different enhanced MIMO types (eMIMO-Types), generating the first CSI report and the second CSI report for the first eMIMO-Type and the second eMIMO-Type, respectively, determining a periodic reporting interval for each of the first CSI report and the second CSI report, and reporting the first and second CSI reports based on the determined periodic reporting intervals using a physical uplink control channel (PUCCH) format 2 or a PUCCH format 3 or a combination of the PUCCH format 2 and the PUCCH format 3.

It is provided a method, including decomposing a channel matrix obtained from a reception channel from a sender to a reception antenna array into its singular vectors, wherein the singular vectors include left-singular vectors and right-singular vectors; allocating powers to the right-singular vectors to obtain power-allocated right-singular vectors; identifying maximum antenna gain directions based on a response function of the reception antenna array and all or a subset of the power-allocated right-singular vectors; calculating, for each of the maximum antenna gain directions or a subset thereof, a respective transmission beamforming vector based on a response function of a transmission antenna array; applying the transmission beamforming vectors or a subset thereof to a transmission via the transmission antenna array to the sender.

Embodiments of the disclosure relate to selective multichannel amplification in a distributed communication system. In this regard, a remote antenna unit (RAU) in the distributed communication system receives downlink digital signals associated with downlink channels having respective downlink channel bandwidths. The RAU digitally scales the downlink digital signals based on respective digital scaling factors to generate scaled downlink digital signals having a substantially equal channel power density in the downlink channels. By digitally scaling the downlink digital signals to provide the substantially equal channel power density in the downlink channels, it is possible to provide substantially uniform radio frequency (RF) coverage range across the downlink channels, thus helping to improve overall RF coverage and user experience in a coverage area of the distributed communication system.

The method comprises receiving periodic CSI feedback configuration information including a periodicity value and an offset value corresponding to a first CSI report, and at least one periodicity value and at least one offset value corresponding to a second CSI report, measuring a first CSI reference signal (CSI-RS) and a second CSI-RS configured for a periodic CSI reporting based on at least two different enhanced MIMO types (eMIMO-Types), generating the first CSI report and the second CSI report for the first eMIMO-Type and the second eMIMO-Type, respectively, determining a periodic reporting interval for each of the first CSI report and the second CSI report, and reporting the first and second CSI reports based on the determined periodic reporting intervals using a physical uplink control channel (PUCCH) format 2 or a PUCCH format 3 or a combination of the PUCCH format 2 and the PUCCH format 3.

A method for transmitting an uplink signal based on a codebook by a UE in a wireless communication system includes: receiving, from a base station, downlink control information (DCI) for determining a precoding matrix applied to transmission of the uplink signal; determining the precoding matrix applied to the transmission of the uplink signal from a codebook subset related to the transmission of the uplink signal based on the DCI; and transmitting, to the base station, the uplink signal based on the determined precoding matrix, I which based on that a difference between phase values applied to antenna ports for the transmission of the uplink signal is maintained in some antenna ports among all antenna port pairs, the codebook subset includes at least one specific precoding matrix applying different phase values to antenna ports included in all or some of the some antenna ports.

Configuration of a line of sight, multiple input, multiple output circular antenna array involves setting an integer number of antenna arrays up to a number of antenna ports for the circular antenna array and a maximum radius for any antenna ring within the circular antenna array. A capacity is determined for each of a plurality of different combinations of each of: an integer number of antenna rings up to a predetermined maximum number of antenna rings, a number of the antenna arrays for each of the number of antenna rings, and angular offsets for that antenna arrays on each of the antenna rings. The determined capacities for the plurality of different combinations are compared.