Sum-Rate Analysis for High Altitude Platform (HAP) Drones with Tethered Balloon Relay

High altitude platform (HAP) drones can provide broadband wireless connectivity to ground users in rural areas by establishing line-of-sight (LoS) links and exploiting effective beamforming techniques. However, at high altitudes, acquiring the channel state information (CSI) for HAPs, which is a key component to perform beamforming, is challenging. In this paper, by exploiting an interference alignment (IA) technique, a novel method for achieving the maximum sum-rate in HAP-based communications without CSI is proposed. In particular, to realize IA, a multiple-antenna tethered balloon is used as a relay between multiple HAP drones and ground stations (GSs). Here, a multiple-input multiple-output X network system is considered. The capacity of the considered M*N X network with a tethered balloon relay is derived in closed-form. Simulation results corroborate the theoretical findings and show that the proposed approach yields the maximum sum-rate in multiple HAPs-GSs communications in absence of CSI. The results also show the existence of an optimal balloon's altitude for which the sum-rate is maximized.Comment: Accepted in IEEE Communications Letter

Effect of imperfect CSI on interference alignment in multiple-High Altitude Platforms based communication

Interference Alignment (IA) offers maximum sum-rate in a wireless X channel. Though IA was proposed for maximizing sum-rate, its application for exploiting high data rate in air-to-ground communication has not been explored much. In this paper, the application of IA in a High Altitude Platform (HAP) to Ground Station (GS) communication is considered. Recent studies suggest that IA provides maximum sum-rate for a 2 × 2 transmitter–receiver system. However, independent channels are required to achieve IA conditions. The application of IA is proposed here for a generalized channel in an HAP-to-GS communication link that takes into account angle-of-departure and angle-of-arrival at the transmitter and at the receiver, respectively. We verify the minimum distance criteria in receiving nodes to achieve independent channels. Receivers are placed at optimal distance for best error performance. Furthermore, in view of an actual scenario, we investigate the effect of imperfect CSI, resulting from changes in imperfection in HAP's stabilization, in the performance of our model. The performance, in terms of Bit Error Rate (BER), is presented for IA and non-IA based communication. For this purpose, an analytical expression is developed for the probability of error. A perfect match is shown between the error rate measured with Monte Carlo simulations and the error probability found using the derived analytical expressions

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Not AvailableSplitting of the genus Penaeus sensu lato into six new genera based on morphological features alone has been controversial in penaeid shrimp taxonomy. Several studies focused on building phylogenetic relations among the genera of Penaeus sensu lato. However, they lack in utilizing full mitochondrial DNA genome of shrimp representing all the six controversial genera. For the first time, the present study targeted the testing of all the six genera of Penaeus sensu lato for phylogenetic relations utilizing complete mitochondrial genome sequence. In addition, the study reports for the first time about the complete mitochondrial DNA genome sequence of Fenneropenaeus indicus, an important candidate species in aquaculture and fisheries, and utilized it for phylogenomics. The maximum likelihood and Bayesian approaches were deployed to generate and comprehend the phylogenetic relationship among the shrimp in the suborder, Dendrobranchiata. The phylogenetic relations established with limited taxon sampling considered in the study pointed to the monophyly of Penaeus sensu lato and suggested collapsing of the new genera to a single genus. Further, trends in mitogenome-wide estimates of average amino acid identity in the order Decapoda and the genus Penaeus sensu lato supported restoration of the old genus, Penaeus, rather promoting the creation of new genera.Not Availabl

Sum-Rate Analysis for High Altitude Platform (HAP) Drones with Tethered Balloon Relay

High altitude platform (HAP) drones can provide broadband wireless connectivity to ground users in rural areas by establishing line-of-sight links and exploiting effective beamforming techniques. However, at high altitudes, acquiring the channel state information (CSI) for HAPs, which is a key requirement to perform beamforming, is challenging. In this paper, by exploiting an interference alignment (IA) technique, a novel method for achieving the maximum sum-rate in HAP-based communications without CSI is proposed. In particular, to realize IA, a multiple-antenna tethered balloon is used as a relay between multiple HAP drones and ground stations (GSs). Here, a multiple-input multiple-output X network system is considered. The capacity of the considered M × N X network with a tethered balloon relay is derived in closed-form. Simulation results corroborate the theoretical findings and show that the proposed approach yields the maximum sum-rate in multiple HAPs-GSs communications in absence of CSI. The results also show the existence of an optimal balloon's altitude for which the sum-rate is maximized

QoS-data rate optimization for fast fading interference alignment X network

Quality of service (QoS) and high data rate are two main parameters that drive the research in wireless communication. Perfect Channel State Information (CSI) at both transmitter and receiver sides is an important condition for achieving QoS and high data rate. But, achieving perfect CSI in mobile transmitters/receivers under fast fading is challenging. That is, frequent CSI updating is required to satisfy QoS requirements under fast fading scenario. In this paper, we consider a multiple transmitter-receiver system, called X network, that has data flow in all the channels. Interference alignment (IA) is a practical solution to achieve maximum capacity in an X network. The present contribution explores the performance of the system with a mobile receiver (or transmitter) that employs CSI estimation using pilot symbols, and further optimize the performance so as to cater both bit error rate (BER) and data rate requirements. Using Monte-Carlo simulations, a novel algorithm is proposed to calculate optimal pilot overhead in M×2 X network or 2×M X network by setting an upper bound on BER. With simulation results we show that the optimal overhead varies with Doppler frequency and Signal-to-Noise Ratio (SNR)

Multiple-high altitude platforms aided system architecture for achieving maximum last mile capacity in satellite communication

Satellite communication provides services to users over wide area. However, the propagation delay and the link budget associated with the long path make the communication difficult. Better link budget and smaller user antennas make high-altitude platform (HAP) based communication one of the favourite choice to last mile users over satellite connectivity. HAPs with overlapped service area form an interference limited system. To this end, interference alignment is proposed as promising solution to maximize capacity between multiple HAPs and ground stations. In this context, explicit expressions for system’s sum-rate and bit error rate (BER) are derived. The sum-rate and BER performance of the proposed scheme are studied for different Rician factors representing different geographical locations. Monte Carlo simulations are used to validate the analytical expressions

Mobile Coverage in Rural Sweden: Analysis of a Comparative Measurement Campaign

Under the umbrella of 1G to 5G, different technologies have been used to provide mobile communication. Various technologies are being proposed to bring a person in remote area under coverage. However, a statistical analysis on what these users get from already existing technologies has not been carried out. We fill this gap by carrying out such a study using a measurement campaign, where we present a framework for analyzing mobile signal strength experienced at the user end. Measurements are taken throughout the Norrbotten county, the northernmost county in Sweden, using mobile phones recording various parameters at regular intervals. Based on measured signal strength, a coverage map has been made via inverse distance weighting (IDW) interpolation. Based on the coverage map, various analyses are carried out on signal strength over residential areas and roads of Norrbotten. Overall, we lay a framework to analyze and quantify the effect of signal strength on users