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The existence of high multipath resolution allows Rake collectors to maximize the signal-to-noise ratio efficiently. However, previous studies show that the conventional Rake receivers do not consider the multipath effect caused by long channel response such as in ultra-wideband wireless system. In this paper, we propose a new statistical selection (SS)-Rake receiver in long multipath channel. The...
Backscatter communication enables a device to transmit or receive data using only the energy harvested from ambient RF signals. It can be realized via employing energy-efficient modulation and demodulation mechanisms. Specifically, a threshold-based demodulation method integrated with signal smoothing has generally been employed for backscatter communications. However, previous proposals considering...
In this paper, we propose a non-orthogonal random access (NORA) technique for the uplink 5G networks, in which user equipments (UEs) make use of the channel inversion so that their received power at the base station (BS) can satisfy a certain threshold condition. In particular, each UE opportunistically adjusts its transmit power according to its channel gain. We also mathematically analyze the system...
In this paper, we investigate the state of the art for the deployment of ECN (Explicit Congestion Notification) on the Internet from a different viewpoint. We carefully choose four data sets as the hosts to be tested. We negotiate an ECN-Capable and a Not-ECN-Capable connections with each host and collect all packets belonging to the connections. By analyzing the TCP/IP header fields of packets belong...
While many companies have launched various wireless chargers in mobile industries, conventional wireless power transfer (WPT) technologies are available only for a very short distance due to large attenuation of the magnetic fields. A magnetic beamforming WPT system achieves an enhanced power transfer efficiency (PTE) with a longer wireless charging distance than conventional WPT technologies by adjusting...
Recently, utilization of position information by global navigation satellite system (GNSS) is expected in various fields. However, it's difficult to show unambiguously accuracy since positioning accuracy varies by measurement environment. We bring sky view factor (SVF) to evaluation of positioning accuracy, and evaluate it positioning accuracy of long time data in the places where SVF are high or...
In recent years, GPS has been widely used as a positioning system using satellites. However, GPS receivers cannot position calculation their own positions when they can watch less than three Satellites directly. Therefore, in an environment where there are many obstacles such as urban area, there is a problem that it may be not possible to receive four or more GPS signals from GPS satellites. In this...
Safety and non-safety application services require a guarantee of network performance, mostly in terms of throughput and packet collision. The current radio propagation path loss models use mean additional attenuation sophisticated fading model and do not consider the obstacle caused due to obstacles of vehicles in LOS of transmitting and receiving vehicles. This affects the attenuation signal at...
With the increase in population and automobiles, the traffic jam in urban areas is becoming a critical issue. These traffic jams especially at the intersections not only increase the delay for drivers, but also increase fuel consumption and the air pollution. The fixed-time traffic light controller is one of critical factors that affect the traffic flow at intersections. This paper proposes a new...
In this paper, we study channel-aware (CA) randomization for secure transmissions in a multicarrier system based on partial channel state information (CSI). In order to see the performance gain by CA randomization, we consider the secrecy rate and show that i) a positive secrecy rate can be obtained even if the channel to an adversary is stochastically more capable than the channel to a legitimate...
V2X technology provides communication services between a vehicle and networks, vehicles, and pedestrians. Especially, LTE based V2X is one of the emerging technologies in communications and automotive industries. To transmit and receive safety message among vehicles with V2X communication, new physical frame structure and receiver algorithm are introduced in 3GPP standardization. In particular, V2X...
Most of IoT applications include large number of distributed sensors which are interesting in specific geographical area. A large number of IoT entities have multiple relations and dynamic connections with each other. And there are many group communication requirements. Flexible multicast mechanism will be essential in such environments but it is difficult to satisfy verious requirements by means...
An offset quadrature amplitude modulation (OQAM)-filterbank based multicarrier (FBMC) has been attracted and nominated as one of new waveforms for 5G communications due to its capability of frequency selectivity, robustness to carrier frequency offset (CFO) and omission of cyclic prefix (CP). Regardless of these advantages, many researchers have claimed pros and cons for the usage of FBMC, among those...
Recent smart devices offer technologies that can measure indoor as well as outdoor locations. In the case of outdoor positioning, a global positioning system (GPS) is generally used. There is a limit to the method of using the GPS signal for indoor positioning. A typical indoor positioning method is to use a beacon based on bluetooth low energy (BLE). However, this method has disadvantages that needs...
In the past, most of the drone was developed for military use, but recently it has been rapidly growing into industrial and civilian markets due to its potential to be applied to various fields. The industry of drones is attracting attention as a model of manufacturing and service convergence, creating synergy by converging with information technology and various services. However, the operating time...
The millimeter wave bands will be used for 5G or IoT to overcome frequency insufficiency. This paper shows relations of received power, multipath delay spread and distance in urban low-rise environments at both 28 and 38 GHz. The wideband characteristics had been measured with a channel sounder, a directional antenna for transmitter, and an omni-directional antenna for receiver in Daejeon area.
This paper presents numerical simulation results to evaluate the interference effect from maritime ESIM to 5G mobile service using 28GHz frequency band. An interference scenario considering the real deployment are established and the Minimum Coupling Loss method is used. From the numerical results, we confirm that the separate distance need to guarantee 5G service quality for outdoor environments...
We have developed a fast tunable laser assembly (FTLA) and 10-Gb/s burst mode receiver (BMR) for realizing photonic switched optical networks. Experimental results show that the FTLA enables to support 90 ITU channels with 50-GHz grids at C-band and switching time in wide tuning range is less than 3-μs. Furthermore, the BMR recovers 10-Gb/s burst signals within 400-ns and a receiver sensitivity of...
This paper considers a wireless power transfer system with multiple antennas by using the multicarrier signal waveforms. A prior art optimizes the waveform with the channel state information at the transmitter (CSIT) to improve the energy harvesting efficiency of the receiver with the non-linear model. The impact of the imperfect CSIT on the energy harvesting capability is studied as a function of...
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