Table 1 Simulation parameters

Carrier frequency

2 GHz

Bandwidth

10 MHz

BS height

25 m

User height

3(n-1)+1.5 m,$n\backsim [1,8]$

Cell radius

500 m

BS transmit power

46 dBm

User speed

3 km /h

Number of users

10/50

Channel model

Winner II C2 NLOS

Noise density

-174 dBm/Hz

Pathloss

34.5+35 log(d)

Channel estimation

Ideal

Receiver algorithm

MMSE

Long-term feedback

100 TTIs

Short-term feedback

1 TTI

Antenna configuration

BS: UPA

$d_{\mathit{\text{tx}}}^{(h)}=0.5\lambda ,d_{\mathit{\text{tx}}}^{(v)}=2\lambda$

$N_{\mathit{\text{tx}}}^{(v)}\times N_{\mathit{\text{tx}}}^{(h)}=8\times 8$

UE: N _rx  = 1

Antenna element

$A_H(\varphi )=-min\left[12{\left(\frac{\varphi }{{\varphi }_{3\mathit{\text{dB}}}}\right)}^2,A_m\right]$

$A_V(\theta )=-min\left[12{\left(\frac{\theta }{{\theta }_{3\mathit{\text{dB}}}}\right)}^2,{\mathit{\text{SLA}}}_v\right]$

A(ϕ,θ) = - min{-[A _H (ϕ) + A _V (θ)],A _m }

ϕ_{3 d B} = 70°,θ_{3 d B} = 65°

A _m  = 25 dB,SLA _v  = 20 dB

Codebook

3D: KPC

$\beta =4,N_v=2N_{\mathit{\text{tx}}}^{(v)},N_h=4N_{\mathit{\text{tx}}}^{(h)}$

2D: DFT

Codebook segment

3D: uniformly segmentation

Non-overlapping: 4 × 8 subsets

Horizontally overlapping: 4 × 16 subsets

Vertically overlapping: 8 × 8 subsets

Horizontally and vertically overlapping: 8 × 16 subsets

2D: uniformly segmentation

Non-overlapping: 8 subsets