The use of unmanned aerial vehicles (UAVs) is growing rapidly across many civil application domains, including real-time monitoring, providing wireless coverage, remote sensing, search and rescue, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. Smart UAVs are the next big revolution in the UAV technology promising to provide new opportunities in different applications, especially in civil infrastructure in terms of reduced risks and lower cost. Civil infrastructure is expected to dominate more than $45 Billion market value of UAV usage. In this paper, we present UAV civil applications and their challenges. We also discuss the current research trends and provide future insights for potential UAV uses. Furthermore, we present the key challenges for UAV civil applications, including charging challenges, collision avoidance and swarming challenges, and networking and security-related challenges. Based on our review of the recent literature, we discuss open research challenges and draw high-level insights on how these challenges might be approached.

Unmanned Aerial Vehicles: A Survey on Civil Applications and Key Research Challenges

Techniques are described for efficiently estimating and compensating for the effects of a communication channel in a multi-carrier wireless communication system. The techniques exploit the fact that the transmitted symbols are drawn from a finite-alphabet to efficiently estimate the propagation channel for multi-carrier communication systems, such systems using OFDM modulation. A transmitter transmits data through a communication channel according to the modulation format. A receiver includes a demodulator to demodulate the data and an estimator to estimate the channel based on the demodulated data. The channel estimator applies a power-law operation to the demodulated data to identify the channel. The techniques can be used in both blind and semi-blind modes of channel estimation.

Channel estimation for wireless ofdm systems

Many use cases of UAVs require beyond visual LOS communications. Mobile networks offer wide-area, high-speed, and secure wireless connectivity, which can enhance control and safety of UAV operations and enable beyond visual LOS use cases. In this article, we share some of our experience in LTE connectivity for low-altitude small UAVs. We first identify the typical airborne connectivity requirements and characteristics, highlight the different propagation conditions for UAVs and mobiles on the ground with measurement and ray tracing results, and present simulation results to shed light on the feasibility of providing LTE connectivity for UAVs. We also present several ideas on potential enhancements for improving LTE connectivity performance and identify fruitful avenues for future research.

The Sky Is Not the Limit: LTE for Unmanned Aerial Vehicles

The 5G System is being developed and enhanced to provide unparalleled connectivity to connect everyone and everything, everywhere. The first version of the 5G System, based on the Release 15 (“Rel-15”) version of the specifications developed by 3GPP, comprising the 5G Core (5GC) and 5G New Radio (NR) with 5G User Equipment (UE), is currently being deployed commercially throughout the world both at sub-6 GHz and at mmWave frequencies. Concurrently, the second phase of 5G is being standardized by 3GPP in the Release 16 (“Rel-16”) version of the specifications which will be completed by March 2020. While the main focus of Rel-15 was on enhanced mobile broadband services, the focus of Rel-16 is on new features for URLLC (Ultra-Reliable Low Latency Communication) and Industrial IoT, including Time Sensitive Communication (TSC), enhanced Location Services, and support for Non-Public Networks (NPNs). In addition, some crucial new features, such as NR on unlicensed bands (NR-U), Integrated Access & Backhaul (IAB) and NR Vehicle-to-X (V2X), are also being introduced as part of Rel-16, as well as enhancements for massive MIMO, wireless and wireline convergence, the Service Based Architecture (SBA) and Network Slicing. Finally, the number of use cases, types of connectivity and users, and applications running on top of 5G networks, are all expected to increase dramatically, thus motivating additional security features to counter security threats which are expected to increase in number, scale and variety. In this paper, we discuss the Rel-16 features and provide an outlook towards Rel-17 and beyond, covering both new features and enhancements of existing features. 5G Evolution will focus on three main areas: enhancements to features introduced in Rel-15 and Rel-16, features that are needed for operational enhancements, and new features to further expand the applicability of the 5G System to new markets and use cases.

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5G Evolution: A View on 5G Cellular Technology Beyond 3GPP Release 15

Methods and systems for sending and receiving an enhanced downlink control channel are disclosed. The method may include receiving control channel information via an enhanced control channel. The method may also include using the control channel information to receive a shared channel. The method may include detecting the presence of the enhanced control channel in a given subframe. The enhanced control channel may be transmitted over multiple antenna ports. For example, code divisional multiplexing and de-multiplexing and the use of common and UE-specific reference signals may be utilized. New control channel elements may be defined, and enhanced control channel state information (CSI) feedback may be utilized. The presence or absence of legacy control channels may affect the demodulation and or decoding methods. The method may be implemented at a WTRU.

Systems and methods for an enhanced control channel

This paper addresses the problem of joint channel and frequency offset estimation and tracking for OFDM systems. The proposed method is based on extended Kalman filtering. The channel taps and the frequency offset are estimated in the time-domain while equalization is performed in the frequency domain. Simulation results demonstrate accurate the tracking capability of the algorithm in scenarios when the channels are time-frequency selective. The frequency offset may be slowly or abruptly changing in time.

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Joint time-domain tracking of channel and frequency offset for OFDM systems

An apparatus and method for selecting a beam group and a subset of beams in a communication system are disclosed. The method includes: measuring channel state information (CSI) on a downlink from a base station (920); identifying a selected beam group out of a set of beam groups according to a wideband property of the CSI (930); identifying a selected subset of beams in the selected beam group according to at least one subband (940). Wherein the characteristic of the set of beam groups depends on a transmission rank and the number of beams in the selected subset of beams is equal to the transmission rank. The method further includes: generating encoded feedback information identifying the selected beam group and the selected subset of beams for each subband in a double codebook format (950), transmitting the encoded feedback information to the base station. A computer program product comprising the computer program code which is configured to cause the apparatus to implement above operations is also disclosed.

Apparatus, method and computer program product for selecting beam group and subset of beams in communication system

In this article, we present a practical coordinated multipoint (CoMP) system for LTE-Advanced. In this CoMP system, cooperation is enabled for cell-edge users via dynamic switching between the normal single-cell operation and CoMP. We first formulate a general CoMP system model of several CoMP schemes. We then investigate a practical finite-rate feedback design that simultaneously supports interference coordination, joint transmission (JT), and dynamic point selection (DPS) with a varying number of cooperating transmission points while operating a single-cell transmission as a fallback mode. We provide both link-level and system-level results for the evaluation of different feedback options for general CoMP operation. The results show that there are substantial performance gains in cell-edge throughputs for both JT and DPS CoMP over the baseline Release 10 LTE-Advanced with practical feedback options. We also show that CoMP can enable improved mobility management in real networks.

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System-level performance of LTE-Advanced with joint transmission and dynamic point selection schemes

From one perspective, a fixed rank r (r>1 is an integer) is determined from received signaling; at least one codeword of rank r is selected from a codebook of antenna weights for controlling inter-cell interference between a serving cell and a neighboring cell; and the selected at least one codeword of rank-r is reported to the serving cell. From a different perspective, the fixed rank r is derived and signaled to user equipments UEs operating in a serving cell; there is received from a UE in the serving cell a report indicating the at least one rank-r codeword; and an indication of the at least one rank-r codeword is forwarded to the neighboring cell. Methods, apparatus and computer programs are detailed as well as embodiments in which different ranks are used for different neighboring cells and narrowband/wideband PMI reporting which can also be different for different neighboring cells.

Best Companion PMI-Based Beamforming

In this paper we address the problem of channel estimation for multiple-input multiple-output OFDM systems for mobile users. A channel tracking and equalization method stemming from Kalman filtering is proposed for time-frequency selective channels. Tracking of the MIMO channel matrix is performed in the time-domain and equalization in the frequency domain. The computational complexity is significantly reduced by applying the matrix inversion lemma. Simulation results are presented using a realistic channel model in typical urban scenarios.

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Mihai Enescu

Papers

Joint time-domain tracking of channel and frequency offset for OFDM systems

Apparatus, method and computer program product for selecting beam group and subset of beams in communication system

System-level performance of LTE-Advanced with joint transmission and dynamic point selection schemes

Best Companion PMI-Based Beamforming

Time-domain method for tracking dispersive channels in MIMO OFDM systems