Abstract: Base stations for MIMO wireless systems embodying efficient channel estimation techniques. One illustrative embodiment includes: an array of multiple antennas to exchange uplink and downlink signals with spatially-distributed user terminals; multiple transmit chains, each coupled to one of the multiple antennas by a respective transceiver that also couples that antenna to a respective one of multiple receive chains; and a controller. Each of the receive chains opportunistically derives estimated uplink channel response coefficients from packet headers in the wireless uplink signals, and the controller determines a steering transform based at least in part on the estimated channel response coefficients. The transmit chains apply the steering transform to spatially-distinct downlink signals to produce antenna-specific downlink signals for each antenna in the array.

Abstract: Disclosed embodiments include methods for control channel design in many-antenna multi-user (MU) multiple-input multiple-output (MIMO) wireless systems. A beacon comprising an identifier of a many-antenna base station is encoded into a base sequence. A plurality of synchronization sequences is generated based on the encoded base sequence and a set of orthogonal beam sequences. The many-antenna base-station transmits, using a plurality of antennas, the plurality of synchronization sequences in a plurality of beam directions associated with the set of orthogonal beam sequences for synchronization and associated with users without knowledge of channel state information (CSI).

Abstract: Technique for full-duplex transmission in many-antenna multi-user (MU) multiple-input multiple-output (MIMO) systems is presented in this disclosure. An estimate of a self-interference channel between a plurality of transmit antennas and a plurality of receive antennas is first obtained. A precoder for self-interference reduction is generated based on minimizing a self-interference power related to the self-interference channel that is present at the plurality of receive antennas. Transmission data are modified using the precoder by projecting the transmission data onto a defined number of singular vectors of the self-interference channel that correspond to the defined number of smallest singular values of the self-interference channel. Data are received in full-duplex mode via the plurality of receive antennas simultaneously with transmitting the modified transmission data.

Abstract: Base stations for MIMO wireless systems embodying efficient channel estimation techniques. One illustrative embodiment includes: an array of multiple antennas to exchange uplink and downlink signals with spatially-distributed user terminals; multiple transmit chains, each coupled to one of the multiple antennas by a respective transceiver that also couples that antenna to a respective one of multiple receive chains; and a controller. Each of the receive chains opportunistically derives estimated uplink channel response coefficients from packet headers in the wireless uplink signals, and the controller determines a steering transform based at least in part on the estimated channel response coefficients. The transmit chains apply the steering transform to spatially-distinct downlink signals to produce antenna-specific downlink signals for each antenna in the array.