Haejoon Jung

This paper aims to unlock the unlicensed band potential in realizing the Industry 4.0 communication goals of the Fifth-Generation (5G) and beyond. New Radio in the Unlicensed band (NR-U) is a new NR Release 16 mode of operation that has the capability to offer the necessary technology for cellular operators to integrate the unlicensed spectrum into 5G networks. NR-U enables both uplink and downlink operation in unlicensed bands, supporting 5G advanced features of ultra-high-speed, high bandwidth

Wireless power and bidirectional wireless data transfer system using a conventional 2-coil inductive link is presented for Internet-of-Things (IoT) and mobile applications without any additional coil or antenna. The proposed system utilizes the dual-band frequency shift-keying and the load shift-keying for the downlink and uplink telemetries, respectively, while ∼140 mW power is delivered to the receiver in the 2-coil inductive link. The data rates for downlink and uplink telemetries are 800 kb/

Concurrent cooperative transmission (CCT) is a cooperative transmission (CT) technique where multiple radios transmit diversity versions of the same message at the same time. Through array gain and diversity gain, CCT achieves a signal-to-noise (SNR) advantage, which can be used for better link reliability and transmission range extension. CCT range extension can enable broadcasting with fewer hops, balance energy in wireless sensor networks, and overcome network partitions. However, there are f

A wireless sensor network (WSN) refers to a network of sensor nodes that collaboratively work to sense, monitor, and control their surrounding environments. As WSNs are integrated into the Internet of Things, it is crucial to protect the network against malicious security attacks considering its wide applicability, such as military monitoring, healthcare, and civilian applications. Thus, in this paper, we consider a physical-layer security technique exploiting analog cooperative beamforming (ACB

Over-the-air computation (AirComp) is a powerful technique to combine data collected from an enormous number of nodes with limited bandwidth availability. When unmanned aerial vehicles are involved in AirComp as flying fusion centers (FFCs), ultrafast data aggregation can be achieved for ubiquitous sensing and environmental surveillance applications. However, one of the main challenges in AirComp is channel estimation. Whereas most of existing studies assume perfect channel estimation, in this l

To extend the transmission range governed by limited transmit power, collaborative beamforming (CB) can be employed with a virtual antenna array (VAA) constructed by an unmanned aerial vehicle (UAV) swarm. CB techniques combined with physical layer security (PLS) algorithms are known to better secure transmissions of sensitive information in the presence of eavesdropping attacks, compared to co-located antenna-based schemes. In particular, analog collaborative beamforming (ACB) with random VAA t

In this letter, we consider the fifth-generation (5G) wireless backhaul network with small cells and millimeter-wave (mm-Wave) communication. We assume mm-Wave wireless backhaul is used for a physically separated 5G macro base station (MBS) to communicate with small-cell base stations (SBSs) that have wired connections to each other. Thus, a user in the coverage of the SBSs can receive its desired signal when at least one of the SBSs is connected to the 5G MBS. However, a blockage problem of lin

In this letter, we propose an analog cooperative beamforming (ACB) technique using random antenna arrays for physical-layer (PHY) secure communications, where the array elements are assumed to be uniformly distributed in a spherical volume. Motivated by the fact that the sidelobe of radiating elements at undesired directions can be used for eavesdropping, the proposed ACB aims at randomizing the radiation pattern at the undesired directions for PHY secure communications. To achieve this aim, it

Traditional rural landscapes emerged from the long term interaction of the natural and anthropogenic environment. These landscapes are now threatened by drastic social-ecological changes. Recent international trends on sustaining cultural landscapes place great emphasis on understanding of multiple values, presented in the landscape, by considering various stakeholder perspectives. It is now recognized that strong community engagement with the landscape should be translated into conservation and

We consider device-to-device (D2D) communications in millimeter-wave (mm Wave) for the future fifth generation (5G) cellular networks. While the mm Wave systems can support multiple D2D pairs simultaneously through beamforming with highly directional antenna arrays, the mm Wave channel is significantly more susceptible to blockage compared to microwave; mm Wave channel studies indicate that if line-of-sight (LoS) paths are blocked, reliable mm Wave communications may not be achieved for high dat

With the rapid proliferation of the Internet of Things (IoT), small devices in various applications generate, process, and exchange security and safety-critical data as well as privacy-sensitive information. However, due to limited hardware capabilities of such small devices, the IoT networks are inherently vulnerable to security attacks. In this context, the analog cooperative beamforming (ACB)-based physical layer security (PLS) technique can be a suitable solution to guarantee security in the

Physical-layer security (PLS) is a promising alternative or complement to cryptography-based solutions, because security key management and distribution required in such schemes are challenging in future wireless technologies with a distributed nature (e.g., Internet-of-Things (IoT) and massive machine-type communication). Motivated by this fact, in this paper, we investigate a PLS algorithm using linear virtual antenna array (VAA) constructed by multiple single-antenna nodes in mobile ad hoc ne

The Opportunistic Large Array (OLA) is one type of cooperative transmission, which provides fast and reliable broadcasts and unicasts in multi-hop networks. While the existing literature on OLAs assumes one-shot transmission with a single packet, we analyze multi-packet OLA transmission within a single flow along strip-shaped networks or OLA-based cooperative routes. When multiple packets are transmitted from the same source using the same channel before the previous packet has cleared the netwo