Codebook design for composite beamforming in next-generation mmWave systems

A base station in a wireless communication system, comprising:

• a memory device for storing program code;
• and
• a hardware processor operatively coupled to the memory device for running the program code to:
• select a beamformer from a beamforming codebook;
• and
• transmit a signal from antenna elements using the selected beamformer by adjusting a gain and a phase of the signal, the antenna elements corresponding to an absolute value and an angle of a respective complex beamforming coefficient from the selected beamformer, wherein the respective complex beamforming coefficient is obtained by the hardware processor by:
• calculating beamforming coefficients of the antenna elements for a composite beam as a summation of beamforming coefficients of corresponding ones of the antenna elements of a beamforming vector for the plurality of disjoint beam lobes of the composite beam;
• and
• normalizing the beamforming vector of the calculated beamforming coefficients such that an absolute value of an m-th beamforming coefficient of the beamforming vector for a constituent beam lobe q is proportional to sinc(δq(n+m)), wherein δq and η are two constant values and sinc(x) is a function defined as sin(x)/x, where sin(x) is the sinusoidal function;
• wherein the beamformer is a composite beam comprised of a plurality of disjoint beam lobes, and each of the plurality of disjoint beam lobes covers a desired angular interval.