Qos-aware Multilayer uav deployment to Provide VoWiFi Service over 5g networks

N + ∑_k∈Z I
SINR = ^Prx , ð14Þ

neglect it for simplicity. L_LoS and L_NLoS represent the average path loss for LoS and NLoS components, respectively, and
can be expressed as [44]
where P_rx represents the received signal power, N accounts for the noise, and each I_k∀k ∈ Z stands for the received interference from any overlapping transmissions.

^LLoS
ð^dÞ ^{= 20 log10
.}4πf _c d^Σ _{+ ξ}

LoS
, ð10Þ

Since we assume that the sources of interference are negligi- ble due to a correct channel planning, SINR can be reduced to SNR and it can be calculated as

c

c
^LNLoSð^dÞ ^{= 20 log10}.^{4πf c d}Σ ^{+ ξNLoS, ð11Þ}
where the first term accounts for the free space propaga- tion loss ξ_LoS and ξ_NLoS represent any additional losses due to the environment (a list of values can be found in [45]) and f _c is the channel frequency.
Finally, the probability of receiving each component is
given by [48]
SINR _dB.^!x , ^!y Σ = RSSI.^!x , ^!y Σ − F − N _dB, ð15Þ

.

.
^Nj_dB ^{= −174 + 10 log10}ð^CBWÞ^{, ð16Þ}
where N is the noise, F accounts for the receiver’s noise figure, and C_BW stands for the signal bandwidth, which depends on the IEEE 802.11 standard revision under consideration.

^PLoS

1 ₁₂

ð^θÞ ^{= , ð Þ}
_{1+ αe}−βθ·180/π+βα

2. 
   Speech Quality and Throughput Evaluation. The goal of this evaluation is to guarantee that (a) the speech quality,
   

given by the QoS function Rð^!d _i, ^!a _jÞ for every D-UAV–A-

^PNLoSð^θÞ ^{=1 − PLoS}ð^θÞ^{, ð13Þ}
where α and β are environment-dependent constants (e.g., rural and urban) as defined in [45] (e.g., α = β =0 for no buildings).

(i) The Signal-to-Interference-plus-Noise-Ratio (SINR) can be calculated by subtracting every noise and

UAV association in the system, is over a minimum threshold (R_min) and (b) that the aggregated throughput at D-UAVs do not exceed the maximum capacity of 5G links (S_max). Both constraints can be formally represented as (17) and (18), respectively.