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

The present invention is designed to provide a user terminal, a radio base station and a radio communication method of novel structures that can achieve a good communication environment. A radio base station non-orthogonal-multiplexes downlink signals for a plurality of user terminals over a given radio resource, a user terminal having received the downlink signals for the plurality of user terminals decodes downlink signal for another user terminal, judges whether or not the downlink signal for the other user terminal has been successfully received, based on the decoding result of the downlink signal, reports a judgement result as to whether or not the downlink signal for the other user terminal has been successfully received and a judgement result as to whether or not a downlink signal for the user terminal has been successfully received, to the radio base station, and then the radio base station executes retransmission control of downlink signals based on reports from the user terminal.

User terminal, radio base station and radio communication method

Cell-free Massive multiple-input multiple-output (MIMO) comprises a large number of distributed low-cost low-power single antenna access points (APs) connected to a network controller. The number of AP antennas is significantly larger than the number of users. The system is not partitioned into cells and each user is served by all APs simultaneously. The simplest linear precoding schemes are conjugate beamforming and zero-forcing. Max–min power control provides equal throughput to all users and is considered in this paper. Surprisingly, under max–min power control, most APs are found to transmit at less than full power. The zero-forcing precoder significantly outperforms conjugate beamforming. For zero-forcing, a near-optimal power control algorithm is developed that is considerably simpler than exact max–min power control. An alternative to cell-free systems is small-cell operation in which each user is served by only one AP for which power optimization algorithms are also developed. Cell-free Massive MIMO is shown to provide five- to ten-fold improvement in 95%-likely per-user throughput over small-cell operation.

Precoding and Power Optimization in Cell-Free Massive MIMO Systems

In this paper, we propose a multi-carrier transmission scheme to overcome the problem of intercarrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) systems. In the proposed scheme, called universal-filtered multi-carrier (UFMC), a filtering operation is applied to a group of consecutive subcarriers (e.g. a given allocation of a single user) in order to reduce out-of-band sidelobe levels and subsequently minimize the potential ICI between adjacent users in case of asynchronous transmissions. We consider a coordinated multi-point (CoMP) reception technique, where a number of base stations (BSs) send the received signals from user equipments (UEs) to a CoMP central unit (CCU) for joint detection and processing. We examine the impact of carrier frequency offset (CFO) on the performance of the proposed scheme and compare the results with the performance of cyclic prefix based orthogonal frequency division multiplexing (CP-OFDM) systems. We use computer experiments to illustrate the efficiency of the proposed multi-carrier scheme. The results indicate that the UFMC scheme outperforms the OFDM for both perfect and non-perfect frequency synchronization between the UEs and BSs.

http://www.ece.tufts.edu/ee/108/Reading7.pdf

Universal-filtered multi-carrier technique for wireless systems beyond LTE

The present invention is designed to improve spectral efficiency in a radio communication system which can use non-orthogonal multiple access (NOMA). Steps are provided in which a radio base station configures one of a plurality of transmission mode including a first transmission mode, which groups a plurality of transmission methods including a transmission method to employ non-orthogonal multiple access (NOMA) and multiple-user multiple-input and multiple-output (MU-MIMO), and a second transmission mode, which groups a plurality of transmission methods including a transmission method to employ this NOMA and open-loop transmit diversity, and transmits a downlink signal for this user terminal based on the configured transmission mode.

Radio base station, user terminal, and radio communication method

This article presents an elaborate coordination technique among multiple cell sites called coordinated multipoint transmission and reception in the Third Generation Partnership Project for LTE-Advanced. After addressing major radio access techniques in the LTE Release 8 specifications, system requirements and applied radio access techniques that satisfy the requirements for LTE-Advanced are described including CoMP transmission and reception. Then CoMP transmission and reception schemes and the related radio interface, which were agreed upon or are currently being discussed in the 3GPP, are presented. Finally, system-level simulation evaluations show that the CoMP transmission and reception schemes have a significant effect in terms of improving the cell edge user throughput based on LTE-Advanced simulation conditions.

Coordinated multipoint transmission/reception techniques for LTE-advanced [Coordinated and Distributed MIMO]

It is an object of the present invention to adequately report the SRS transmission timing and SRS parameters to a mobile terminal apparatus, when an aperiodic SRS is adopted, and efficiently use radio resources to be used for SRS transmission. A radio base station apparatus that reports SRS transmission control information to a mobile terminal apparatus and controls transmission of an SRS by the mobile terminal apparatus, and the radio base station apparatus has an SRS setting section that selects bit information to report to the mobile terminal apparatus, from a table having bit information to indicate not to trigger the SRS and bit information to indicate to trigger the SRS using a default SRS parameter, and a reporting section that reports the bit information for the mobile terminal apparatus using a downlink control channel.

Radio base station apparatus, mobile terminal apparatus and radio communication method

An objective is to improve communication quality by reducing an insertion loss or the like of a diplexer inserted to reduce a leakage from an uplink band to a downlink band in different bands. A mobile communication method according to the present invention includes the steps of: transmitting simultaneous transmission capability information from a mobile station UE to a radio base station eNB, the simultaneous transmission capability information indicating whether or not the mobile station UE can transmit uplink data signals via multiple carriers in the same sub-frame while performing uplink CA; performing scheduling for the mobile station UE by the radio base station eNB on the basis of the simultaneous transmission capability information; and performing communication by the mobile station UE on the basis of the scheduling information.

Mobile communication method, wireless base station, and mobile station

In a radio communication system including a mobile station and a base station apparatus for communicating with the mobile station according to a SC-FDMA scheme in uplink, the mobile station includes a transmitting unit configured to transmit at least one of a first signal and a second signal; and a Sounding RS transmitting unit configured to determine a transmission band for a Sounding Reference Signal (Sounding RS) based on mapping information of at least one of the first signal and the second signal

Base station apparatus, mobile station, radio communication system, and communication control method

The present invention is designed to provide a radio communication system, a user terminal and a radio communication method that make it possible to monitor communication quality adequately even when a new radio resource structure is employed. A radio communication system is provided, which transmits downlink control information from a radio base station to a user terminal by using an enhanced downlink control channel that is frequency-division-multiplexed with a downlink shared data channel, and which also monitors downlink quality based on the received quality of downlink reference signals that are transmitted from the radio base station to the user terminal, and, in this radio communication system, the user terminal determines radio link failures by comparing the received quality of the downlink reference signals transmitted from the radio base station, against one or both of first criteria, which are constituted of two thresholds that correspond to predetermined block error rates of a downlink control channel, and second criteria, which are constituted of two thresholds that are different from the two thresholds of the first criteria.

Daisuke Nishikawa

Papers

Coordinated multipoint transmission/reception techniques for LTE-advanced [Coordinated and Distributed MIMO]

Radio base station apparatus, mobile terminal apparatus and radio communication method

Mobile communication method, wireless base station, and mobile station

Base station apparatus, mobile station, radio communication system, and communication control method

Radio communication system, user terminal and radio communication method