A pilot selection method adapted for selecting rank-2 pilot patterns for a macrocell advanced base station (ABS), a femtocell ABS and a non-macrocell and non-femtocell ABS is proposed along with a wireless communication system and a base station thereof. Different rank-2 pilot pattern is selected for a femtocell ABS from its overlay macrocell ABS and non-macrocell and non-femtocell ABS rank-2 pilot patterns. Another pilot selection method for selecting a rank-1 pilot pattern for a femtocell ABS co-located with at least a macrocell ABS is also proposed. Different rank-1 pilot pattern is selected for a femtocell ABS from its overlay macrocell ABSs using rank-1 and/or rank-2 pilot patterns, where some of the macrocell ABSs can use rank-2 pilot patterns and the rest of the macrocell ABSs just use rank-1 pilot patterns. Also, different rank-1 pilot pattern is selected for the femtocell ABS from its neighboring femtocell ABSs using rank-1 pilot patterns.