Facebook, Inc.

Sungwoo Park

Ali Yazdan Panah

Jeonghun Park

Apparatuses, methods, and systems for selecting an ADC for each RF chain of an RRU are disclosed. One embodiment of the RRU includes a plurality of antennas and a plurality of RF chains configured to receive a plurality of wireless signals, A plurality of outputs of the RRU connected to a front-haul, wherein the front-haul electrically connects the plurality of outputs of the RRU to a baseband unit (BBU), wherein each of the outputs is connected to an output of one of a plurality of ADCs. Further, the RRU selects a one of the plurality of ADCs having the plurality of ADC resolutions for each of the RF chains based on the capacity of the front-haul, a channel gain of each of the RF chains, and a performance parameter of the RRU. A switch connects each of the RF chains to a corresponding one of the plurality of ADCs.

Selection of an ADC for each RF chain of a remote radio head unit

Apparatuses, methods, and systems for beamforming in antenna systems are disclosed. A method includes determining an unconstrained analog precoding matrix (F), wherein the unconstrained analog precoding matrix (F) is determined based on M dominant eigenvectors of the sum of spatial channel covariance matrices of K users, and wherein K indicates a number of users communicating with a base station. The method further includes determining a constrained analog precoding matrix (F) based on the unconstrained analog precoding matrix (F), determining a compensation matrix (F), digitally multiplying K inputs with a multiple-input multiple-output (MIMO) precoding matrix (F) generating M outputs, digitally multiplying the M outputs with the compensation matrix (F) generating M compensation outputs, generating M analog frequency-up-converted signals based on the M compensation outputs, and analog multiplying the M analog frequency-up-converted signals with the analog precoding matrix (F) generating N output signals for transmission, wherein N is greater than M.

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Austin, TX, United States of America

Sungwoo Park