QoS-Aware Multilayer UAV Deployment to Provide VoWiFi Service over 5G Networks

Table 1

Related work comparison.

Ref.	Objective function	Variables			Network technologies		Considerations
		Placement	Trajectory	Resource allocation	Access	Backbone	SINR	BW	Speech quality	Energy
[17]	max. throughput	✓	✗	✗	FDMA	FDMA	✓	✗	✗	✗
[18]	max. throughput	✓	✗	✓	Cellular	Cellular	✓	✗	✗	✓
[19]	max. throughput	✓	✗	✓	Cellular	Cellular	✓	✓	✗	✗
[20]	max. downlink rate	✓	✗	✓	Cellular	Cellular	✓	✗	✗	✗
[21]	min. maximum traffic demand	✓	✗	✓	Cellular	Cellular	✓	✗	✗	✗
[22]	min. path loss	✓	✗	✓	NOMA	Cellular	✓	✗	✗	✓
[23]	min. transmit power or max. rate	✓	✗	✓	NOMA	Cellular	✓	✗	✗	✓
[24]	min. UAVs and max. coverage	✓	✓	✓	Cellular	Cellular	✓	✓	✗	✗
[25]	min. UAVs and max. coverage	✓	✓	✓	Cellular	Cellular	✓	✓	✗	✗
[26]	max. energy efficiency	✗	✓	✗	mmWave	Cellular	✓	✗	✗	✓
[27]	min. power allocation	✗	✓	✓	OFDMA	OFDMA	✓	✗	✗	✓
[28]	min. energy consumption	✗	✓	✓	Cellular	Cellular	✓	✗	✗	✓
[29]	max. spectrum and energy eff.	✗	✓	✓	TDD	TDD	✗	✗	✗	✓
[30]	max. spectrum and energy eff.	✗	✓	✓	TDD	TDD	✗	✗	✗	✓
[31]	max. minimum throughput	✗	✓	✓	Cellular	Cellular	✗	✓	✗	✗
[32]	max. minimum user rate	✗	✓	✓	OFDMA	OFDMA	✓	✗	✗	✗
[33]	max. minimum user rate	✗	✓	✓	TDMA	TDMA	✓	✗	✗	✓
[34]	max. end-to-end throughput	✗	✓	✓	Cellular	Cellular	✓	✗	✗	✓
[35]	max. end-to-end throughput	✗	✓	✓	Cellular	Cellular	✓	✗	✗	✓
[36]	min. outage probability	✗	✓	✓	Cellular	Cellular	✓	✗	✗	✓
[15]	min. UAVs and user radio energy	✓ (single-layer)	✗	✓	WiFi	N/A	✓	✓	✓	✓
[16]	min. UAVs and UAVs’ energy	✓ (single-layer)	✗	✓	WiFi	N/A	✓	✓	✓	✓
This paper	min. UAVs and user coverage	✓ (multilayer)	✗	✓	WiFi	5G	✓	✓	✓	✗