Research Article

Genetic Algorithm-Based Beam Refinement for Initial Access in Millimeter Wave Mobile Networks

Algorithm 1

GA-based beam refinement algorithm.
In each time slot with instantaneous channel realization , do the followings:
(I)Initialization: Consider , e.g., , sets of precoding matrices and combining matrices ,
, randomly selected from the pre-defined codebook and .
(II) Selection: For each and , evaluate the instantaneous value of the objective metric ,
, for example end-to-end throughput (5). Find the best beamforming matrix which
results in the best value of the considered metric, named as the Queen, e.g., and satisfies
, if the end-to-end throughput is the objective function.
(III) Save the Queen: ,
(IV) Genetic operation I-Crossover: Create , e.g., , beamforming matrices and ,
, around the Queen and . These sets are generated
by making small changes in the Queen and .
(V) , , .
(VI) Genetic operation II-Mutation: Regenerate the remaining sets and , ,
randomly with the same procedure as in Step (I).
(VII) Go back to Step (II) and run for iterations, is a fixed number decided by designer.
Return the final Queen as the beam selection rule for the current time slot.