3D Placement of a New Tethered UAV to UAV Relay System for Coverage Maximization
1.1. Related Work
- Proposing a new relay system TU2U2G system. It uses the TUAV as a viable alternative to replace a BS and provide seamless service over a cable that simultaneously supplies a stable power and a reliable wired data-link connection from a ground control station . Compared to the BS, TUAV improves the system coverage due to its high altitude. Also, it overcomes antenna down-tilting, which increases the path loss between the BS and the UAV in the cellular system .
- Formulating the optimization problem to maximize UAV relay station coverage under the power budget and maximum UAV height constraints. For simplicity, the 3D placement of the UAV is decoupled to the vertical and horizontal placement. Then, a 3D placement algorithm for the system is proposed.
- Numerical results are presented. TU2U2G the system shows better results than the cellular system in terms of optimum UAV height, maximum coverage radius, and maximum distance between the BS and the UAV.
2. System Models
2.1. Channels Models
2.1.1. A2G Channel
2.1.2. U2U Channel
2.2. UAV Transmission Power, SNR, and Probability of Coverage
2.3. Problem Formulation
3. The Proposed 3D Placement of UAV
3.1. Altitude Optimization for Maximum Coverage
3.1.1. Finding the UAV Height for Maximum Coverage Radius between UAV and Ground User
3.1.2. Finding the UAV Height for Maximum Distance between TUAV and UAV
3.2. Horizontal Placement of UAV
3.3. 3D Placement Algorithm
|Algorithm 1: Obtain Optimal 3D Location (d, R, , )|
Finding by solving the problem in (24).
Then, substituting by in (5) to calculate .
Then, substituting by and in (25) to calculate .
2 Obtain ∆
Finding by solving the problem in (26).
Then, substituting by in (7) to calculate .
Then, substituting by and in (27) to calculate ∆.
|3 Calculate∆ = absolute value of ()|
If (∆ > ∆) then
∆h = ∆
∆h = ∆
If ( > ) then
If (∆ = 0) then
= + ∆
= + ∆
|4 ObtainR from (25)|
|5 Obtaind from (27)|
6 Solve a problem: obtain UAV coverage center ( and users’ coverage N by solving the problem (15)
4. Numerical Results
Conflicts of Interest
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|Ref No.||UAV Placement for||Pros||Cons|
|||Coverage maximization||Jointly optimizes the 3D UAV placement and path loss compensation factor||References [6,7,8,9,10,11,12,13,14,15,16] consider only the power constraints of the communication link between UAV and the ground user mobile station (MS) but do not consider the power constraints of the communication link between a UAV and the BS|
|||Minimizes the total transmit power required to provide wireless coverage for indoor users|
|||Maximizes the number of covered users with minimum transmission power|
|||Maximizes the number of served users with different quality-of-service requirements|
|||finds the optimum UAV altitude|
|||Throughput maximization||A joint trajectory and resource allocation algorithm|
|||A joint transmit power and trajectory optimization algorithm|
|||Optimizing the scheduling of multi-user communication and association jointly with the trajectory of UAVs and power control|
|||Joint optimization of Trajectory and resource allocation|
|||Algorithm for downlink sum-rate maximization|
|||Algorithm for UAV placement based on sparse recovery|
|||Throughput maximization||Maximizes the average achievable rate through the one-dimensional linear search||References [17,18,19,20,21,22,23,24,25] are proposed for UAVs to assist the cellular network. However, the antenna down-tilting and low height of the cellular base station (BS) limits the ability of the UAV relay station to reach high altitudes due to the power constraint on the path between a UAV and a BS.|
|||The optimization problem is formulated to maximize the system throughput.|
|||An algorithm to find the UAV optimal position based on LOS information|
|||Explores the relationship between system throughput and placement of a UAV|
|||Jointly optimizes throughput and the UAV’s trajectory|
|||Sum logarithmic rate of the users maximize||An algorithm to find the 3D locations of UAVs besides the user-BS associations and bandwidth allocations of the wireless backhaul|
|||Data rate maximization||Algorithms for deploying a multi-relay network to maximize the end-to-end achievable rate|
|||Power loss, outage probability, and BER minimization||An approach to find the optimum altitude of UAV|
|||Optimizing the overall network delays||An approach to optimize the overall network delays|
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Safwat, N.E.-D.; Hafez, I.M.; Newagy, F. 3D Placement of a New Tethered UAV to UAV Relay System for Coverage Maximization. Electronics 2022, 11, 385. https://doi.org/10.3390/electronics11030385
Safwat NE-D, Hafez IM, Newagy F. 3D Placement of a New Tethered UAV to UAV Relay System for Coverage Maximization. Electronics. 2022; 11(3):385. https://doi.org/10.3390/electronics11030385Chicago/Turabian Style
Safwat, Nour El-Din, Ismail Mohammed Hafez, and Fatma Newagy. 2022. "3D Placement of a New Tethered UAV to UAV Relay System for Coverage Maximization" Electronics 11, no. 3: 385. https://doi.org/10.3390/electronics11030385