Method for Efficient and Cost Effective Orthogonal Angular Beamforming

A method to quantize the RF signal beams and index them in claim (2) in the two-dimensional angular space over the UPA,

• a. using a reference antenna element, e.g., the center element (0,0), of the UPA,
• b. using a reference component one-dimensional ULA and another component one-dimensional ULA of the UPA, intersecting at the reference antenna element,
• c. using one-dimensional Fourier Transform to transform the signals from the antenna space of the reference component ULAs into the one-dimensional angular space respectively,
• d. combining the two separate dimensions to form a composite, two-dimensional angular signal paths of the twos angles of the elevation and azimuth in the direction of the RF signal impinging upon (as the receiver), or emitting from (as the transmitter), the UPA,
• e. the composite angular signal paths form a channel vector for the UE, with each element of the channel vector corresponding to an element of the UPA in two dimensions.

A method to form the channel vector for each available UE transmitting a signal to, or receiving a signal from, the UPA of claim (2), from the channel estimation of that UE,

• a. producing the first one-dimensional angular channel vector from the first reference component ULA and producing the second one-dimensional angular channel vector from the second reference component ULA, using one-dimensional Fourier Transform,
• b. using the angular cosines and sines of the two angular channel vectors to construct the combined two-dimensional channel vector of the whole UPA for that UE,
• c. calculating the complex gain of each element of the two-dimensional channel vector, corresponding to each two-dimensional angular signal path, as a function of the complex gains of the elements of the respective one-dimensional channel vectors,
• d. each element of the two-dimensional channel vector, corresponding to the two-dimensional angular signal path, is the gain multiplied by the phases determined by the two-dimensional UPA steering vector (as the transmitter) or response vector (as the receiver).

A schedule method to produce a K×M composite channel matrix in the downlink of claim (9), where

• a. the kth UE corresponding to the UE's channel vector from the available UEs is scheduled to transmit,
• b. the scheduled UE, based on the total gain of the channel vector, i.e., of its signal paths, results in higher SNR of the received signal, from the BS to the UE,
• c. the total gain of the channel vector is defined as the norm of the channel vector,
• d. the objective of scheduling UEs is to create a channel matrix that has no more than/non-zero gain elements in each component channel vector of the channel matrix, where/is no greater than a small integer, e.g., 4, such that the non-zero gain values per channel vector results in a simplified matrix inversion solution.

A filtering method to produce a K×M composite channel matrix in the downlink of claim (11), where

• a. the channel vector of the kth UE contains more than one non-zero gain values,
• b. each channel vector element is filtered by its total gain as the ratio of the gain value to the total gain,
• c. if the gain of the element is lower than a threshold, the outlier non-zero gain is zeroed so that those corresponding angular signal paths are available to other UEs,
• d. the threshold is either an absolute value, or a ratio of the gain to the total gain of the channel vector,
• e. the total gain of the channel vector is defined as the norm of the channel vector.

A nulling method to produce a composite channel matrix for K UEs in the downlink, after the filtering of each channel vector from claim (12), where

• a. the same angular signal path are non-zero for both UE k and UE i,
• b. the signal quality of UE k is much greater than that of UE i, by a threshold,
• c. the angular signal path is set to null in the channel vector for UE i,
• d. the threshold above may be determined as an absolute value, or it may be determined as a ratio to the total gain of the channel vector.

A clustering method to produce a composite channel matrix for K UEs, after the filtering of the channel vector from claim (12), where

• a. the channel vector of the kth UE contains n (n<M) non-zero gain values,
• b. the channel vector is organized into b (b<K and b<=n) contiguous clusters of non-zero gain values,
• c. each contiguous cluster consists of any angular signal path of non-zero gain values that is at least adjacent to another angular signal path in the same cluster,
• d. two angular signal paths are adjacent if they are located next to each other in the two-dimensional angular space of the UPA,
• e. thus intra-path diversity of all the high gain angular signal paths of a UE are retained, for each cluster, in the channel matrix that results in enhanced signal quality.

A splitting method to produce a composite channel matrix for K UEs, after the clustering of the channel vector from claim (15), where

• a. the channel vector of the kth UE contains b clusters of angular signal paths of non-zero gain values,
• b. the channel vector is split into b independent channel vectors, each of which contains a single cluster,
• c. b pseudo-UEs, corresponding to each split (new) channel vector, is added into the set of available UEs, and the size of the set of available UEs is incremented,
• d. thus a UE is able to produce more than one pseudo-UEs, which provides inter-path diversity between independently faded signal paths to the same UE, which enhances overall signal quality when the signal paths to the user is poor.