Is appropriate for the link between the SN as well as the RN. Relay Nodes-to-UAV and UAV-to-Sink links [403]: Communication requirements that have medium transmission distances including IEEE802.11 (WiFi) are appropriate for connections in between RNs and UAVs or UAVs and Sinks. The communication normal has communication distances from 100 m to various hundred meters, and transfer prices from 1 Mbps to 54 Mbps. Regular IEEE 802.16 features a speed of up to 70 Mbps. Therefore, it is actually suitable for UAVs operating at high altitudes of various kilometers. The model of the transmission channel involving the UAV with height h and coverage radius R and the ground stations is pointed out within the paper [44]. The path loss are going to be calculated according to the formula: L(h, R) = P( LOS).L LOS P( NLOS).L NLOS P( LOS) = 1 1 .exp(- [ 180 . – ]) (1) (two) (3) (4)4.. f c .d) LOS c 4.. f c .d L NLOS (dB) = 20log NLOS c L LOS (dB) = 20.log(exactly where P( LOS) is definitely the probability to have line of sight (LOS) at angle , P(NLOS) is definitely the probability to have non-line of sight (NLOS) at angle , may be the angle among the antenna on the UAV and also the antenna in the ground station, L LOS and L NLOS would be the path loss for line of sight and non-line of sight path, and is often a continual, f c is definitely the carrier frequency, d could be the distance in between the UAV as well as the ground station, c may be the flight speed of the UAV, LOS and NLOS are contingency loss. Electronics 2021, ten,six ofTable 1. Typical communication technologies for UAV-assisted WSNs information collection.Sort of LinksIEEEStandards IEEE 802.15.Specifications Unlicensed, 2.4 GHz, TDMA Unlicensed, two.four GHz, DSSS Unlicensed, 2.4 GHz, DSSS Unlicensed, five GHz, OFDM Unlicensed, 5 GHz, QAM Unlicensed, 2.four GHz, DSSS Unlicensed, 2.four GHz, DSSS, OFDM Unlicensed, 2.four GHz and 5 GHz, DSSS, OFDM three GHz 3000 MHz Unlicensed, two.four GHz, DSSS, OFDMTRDelayCRProtocol55 Mbps25 ns100 mUWBSensor to cluster head [379]Short distance IEEE 802.15.4 Extended distance250 Dimethoate Protocol kbps15 ms100 m 1600 m 2500 mZigbee ZigbeeProIEEE 802.15.250 kbps15 ms Slot time: 9 , SIFS: 16 , DIFS: 34 , Propagation delay: 1 DIFS: 34 SIFS: 16 Slot time: 9 Slot time: 20 , SIFS: 10 , DIFS: 50 , Propagation delay: 1 DIFS: 50 SIFS: 20 Slot time: 20 Slot time: 9 , SIFS: 16 , DIFS: 34 , Propagation delay: 1IEEE 802.11a Higher data rate IEEE 802.11ac Air to Air and UAV to Ground station [403]54 Mbps120 m6933 Mbps120 mLow to medium data rate Low to higher data rate Medium to high data rateIEEE 802.11b11 Mbps140 mIEEE 802.11g54 Mbps140 mWi-FiIEEE 802.11n600 Mbps250 mUHF VHF UAV to UAV [45,46] IEEE 802.11g54 MbpsDIFS: 50 SIFS: 20 Slot time: 20140 mWi-FiAcronym: UWB: ultra-wideband; CH: cluster head; DSSS: direct sequence spread spectrum; TDMA: time-division multiplexing; OFDM: orthogonal frequency division multiplexing; QAM: quadrature amplitude modulation; DIFS: distributed coordination function (DCF) inter-frame spacing; SIFS: shortest inter-frame spacing; UHF: ultra higher frequency; VHF: incredibly high frequency; TR: transmitting rate; CR: communication variety.UAVs-to-UAVs communication links [45,46]: Collaborative communications are crucial inside a group in the UAVs for networking assistance and service elements, as shown inside the Figure three. They will share/exchange or forward information to every single other. The UAVs use several different communication technologies to communicate among them or with other systems, for instance the Ground Handle Stations (GCS), WSNs, and on-ground mobile robots.Electronics 2021, 10,7 ofSimilarly, we’ve got the model of your communication channel b.
