Cooperative clustering for enhancing MU-massive-MISO-based UAV communication
Methods, apparatuses, and systems for organizing data delivering unmanned aerial vehicles (UAVs) are provided. Inter-cluster coordinators can organize data delivering unmanned aerial vehicle base stations (UAV-BSs). Various beamforming techniques (e.g., LZFBF and ZFBF) can be incorporated, and the inter-cluster coordinator can operate on a base station that serves as a controlling network node.
1. A method for identifying optimum hovering locations for unmanned aerial vehicle base stations (UAV-BSs) communications, the method comprising:
identifying user locations;
defining a hovering grid that includes the user locations;
determining an absolute value of directional cosine separation |Ω k,un | for each grid point, which is the separation between directional cosines between the uth user and the kth user of the nth UAV-BS;
detecting all grid points (y,z) with directional cosine separation |Ω k,un |=2/N t ×q and q≤N t −1, wherein N t is the number of antenna arrays for the nth UAV-BS and q is an integer;
calculating the distance from all grid points (y,z) to each user; and
assigning grid point (y,z) to the UAV-BSs (y n ,z n ) based on the minimum distance to their intended user.
2. The method of claim 1 , wherein the hovering grid is symmetric around two or more users.
3. The method of claim 1 , wherein the directional cosine separation for each grid point is determined by Ω k,un =cos Φ un −cos Φ kn , which is the separation between directional cosines between the uth user and the kth user of the nth UAV-BS.
4. The method of claim 1 , wherein the method is executed partially or entirely within one or more of the UAV-BSs.
5. The method of claim 1 , further comprising incorporating transmit (Tx) beamforming.
6. The method of claim 1 , further comprising incorporating linear zero-force (LZFBF) beamforming.
7. The method of claim 1 , wherein the method does not include sending channel state information.
8. The method of claim 1 , wherein if no grid points are found in the detecting all grid points (y,z) with directional cosine separation |Ω k,un |=2/N t ×q and q≤N t −1, the method further comprises selecting grid points with directional cosine separation closest to an integer multiple of 2/N t that can satisfy the constraints in
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9. The method of claim 1 , wherein the method further comprises incorporating linear single user beamforming (LSUBF).
10. The method of claim 1 , wherein the method further comprises incorporating zero-forcing beamforming (ZFBF).
11. The method of claim 1 , wherein the method includes millimeter wave communication technology.
12. An inter-cluster coordinator for identifying optimum hovering locations for unmanned aerial vehicle base stations (UAV-BSs) comprising a processor, volatile and non-volatile memory, antennas suitable for communicating with the unmanned aerial vehicle base stations (UAV-BSs) and a non-transitory machine-readable medium with computer executable instructions stored thereon that when executed by a processor perform the method of:
identifying user locations;
defining a hovering grid that includes the user locations;
determining an absolute value of directional cosine separation |Ω k,un | for each grid point, which is the separation between directional cosines between the uth user and the kth user of the nth UAV-BS;
detecting all grid points (y,z) with directional cosine separation |Ω k,un |=2/N t ×q and q≤N t −1, wherein N t is the number of uniform linear antenna arrays for the nth UAV-BS and q is an integer;
calculating the distance from all grid points (y,z) to each user; and
assigning grid point (y,z) to the UAV-BSs (y n ,z n ) based on the minimum distance to their intended user.
13. The inter-cluster coordinator of claim 12 , wherein the inter-cluster coordinator is a UAV-BS.
14. The inter-cluster coordinator of claim 12 , wherein the method further comprises transmit (Tx) beamforming.
15. The inter-cluster coordinator of claim 12 , wherein the method further comprises linear zero-force (LZFBF) beamforming.
16. The inter-cluster coordinator of claim 12 , wherein the method does not include sending channel state information.
17. The inter-cluster coordinator of claim 12 , wherein the method includes incorporating millimeter wave communication technology.