NLOS Conditions Research Articles

Analisis Koeksistensi Jaringan LTE Non Lisensi dan Wi-Fi Pada Frekuensi 5GHz

By the 2020 the traffic internet demand will be increasing, so that the utilization of spectrum frequency should be maximize and use wisely. LTE-U which is using unlicensed spectrum frequency may be option to fulfil the demand of the internet traffic. Unfortunately it has to adapt and coexistence with Wi-Fi which already exist in unlicensed spectrum frequency. In this research, will talk about the minimum distance needed so that LTE-U eNodeB and Wi-Fi can be coexistence in indoor and outdoor deployment LOS and NLOS condition. The coexistence analyze in ACIR value. The result, minimum distance needed is in range 16 m-35 m for indoor deployment. In the other hand 51 m-199 m for outdoor deployment. With software simulation in 51 m distance the mean CINR value is 15 dB, and for 16 m distance the mean SIR value is 0.62 dB.

QoS Analysis of Wireless Sensor Networks for Temperature and Humidity Monitoring and Control of Soybean Seed Storage Based IOT Using NodeMCU

Based on data from Central Bureau of Statistics in 2016 - 2020 soybean production deficit, the main factor is the decline in the quality of soybean seeds temperature and humidity sensitive. And so we need a system of monitoring and control of temperature and humidity container store soya beans. Wireless sensor network wireless technology that consists of a collection of sensor nodes distributed on a given area can support the communication between the sensor nodes using the system and sensor NodeMCU DHT11. This research was to analyze the WSN QoS monitoring system and temperature and humidity control soybean seed store container-based IOT using NodeMCU clients and coordinators are connected to an access point for sending data to the server in realtime. Tests carried out by putting the sensor node at 3 points with a distance variation of the coordinator and a data packet transmission interval. The test results obtained using a star topology indoor NLOS conditions optimal distance sensor node 3 which is 4 meters and the delivery interval 40s with packet loss value of 0-20%, delay 1.154 - 5,92s, jitter 0.241 to 7.57 ms, and throughput 66.32 bits / s. WSN protocol IOT uses MQTT NodeMCU and goes well with a low throughput value is 529.81 bps to 544.85 bps can still generate a delay kualiatas 200.33 to 270.83 ms and packet loss from 0 to 1.284% which is good. 92s, jitter 0.241 to 7.57 ms, and the throughput of 66.32 bits / s. WSN protocol IOT uses MQTT NodeMCU and goes well with a low throughput value is 529.81 bps to 544.85 bps can still generate a delay kualiatas 200.33 to 270.83 ms and packet loss from 0 to 1.284% which is good. 92s, jitter 0.241 to 7.57 ms, and the throughput of 66.32 bits / s. WSN protocol IOT uses MQTT NodeMCU and goes well with a low throughput value is 529.81 bps to 544.85 bps can still generate a delay kualiatas 200.33 to 270.83 ms and packet loss from 0 to 1.284% which is good.

Novel MF-TDMA/SCPC switching algorithm for DVB-RCS/RCS2 return link in railway scenario

This work focuses on the return channel resource allocation in the DVB-RCS/RCS2 system for mobile terminals. A continuous carrier (CC) operation mode based on DVB-S2/S2X is considered and investigated. The paper focuses on the possibility of transmitting simultaneously in multifrequency–time division multiple access (MF-TDMA) or single channel per carrier (SCPC) medium access techniques, as suggested by a previous DVB-RCS+M standard. The introduction of this capability has also been analyzed for a new DVB-RCS2 standard that gives the possibility of using both return link (RL) modalities. Moreover, we propose a detailed study of the RL channel in a satellite platform in order to understand the operative range of SCPC and MF-TDMA techniques. The contribution seeks to provide some threshold indications to network operators for dynamically managing satellite resources.We considered the railway market, which is characterized by an N-LOS condition due to blockage caused by tunnels, vegetation, and buildings, as the reference scenario. Furthermore, we introduced a transparent gap filler (GF) solution to overcome this issue. Simulation campaigns are shown, in order to give satellite operators some guidelines, when they want to make use of this hybrid channel modality.

Transparent Gap Filler Solution over a DVB-RCS2 Satellite Platform in a Railway Scenario: Performance Evaluation Study

In this work, a performance study of a system equipped with a transparent Gap Filler solution in a DVB-RCS2 satellite platform has been provided. In particular, a simulation model based on a 3-state Markov chain, overcoming the blockage status through the introduction of a transparent Gap Filler (using devices on both tunnel sides) has been implemented. The handover time, due to switching mechanism between satellite and Gap Filler, has been taken into account. As reference scenario, the railway market has been considered, which is characterized by a N-LOS condition, due to service disruptions caused by tunnels, vegetation and buildings. The system performance, in terms of end-to-end delay, queue size and packet loss percentage, have been evaluated, in order to prove the goodness of communications in a real railroad path.

Assessing Capabilities of Commercial WiMAX Networks for Deliverling Real-Time Surveillance Video Traffic in Uplink

Abstract Streaming video in uplink is an interesting opportunity for network operators for capitalizing unused part of bandwidth (due to Internet asymmetry). The uplink seems not optimized nowadays due to lack of business cases. The main challenge however is bursty and unpredictable nature of wireless channel observed especially as mobility comes into play in current broadband networks. That is why in this paper, we have approached the diagnosis of commercial mobile WiMAX network towards the capabilities of assuring real-time video in uplink direction. We present results of drive tests showing that delay in WiMAX networks for LOS-NLOS (Line of sight - No n line of sight) mobile conditions is largely contributed by uplink direction (60-90% of RTT (Round trip time)) whereas downlink directions hardly ever exceeds 40ms. We show that enabling MIMO-A(Multiple Input Multiple Output) can decrease delays by 100ms in NLOS conditions and decrease delay variation by up to 90%. For each of tests we have presented exact probabilities of particular modulations involved based on channel realizations.

An empirical investigation of RSSI-based distance estimation for wireless indoor positioning system

RSSI-based distance estimation techniques for wireless indoor positioning system require extensive offline calibration to construct propagation model in order to describe the relationship between received signal strength and distance. This paper investigates the accuracy of the well-known propagation models against the measured data at indoor building. From the results, the dual slope model exhibits the best propagation model and it is chosen as the reference for further investigation. The accuracy of dual slope model in distance estimation suffers from the degradation due to the presence of Non Line of Sight NLOS condition between mobile station and access point. Therefore, to further improve the accuracy, this paper studies the effect of breakpoint distance and evaluates two simple techniques, running variance and kurtosis index, to identify the NLOS condition. Once the NLOS condition is identified, the best dual slope model can be selected for accurate distance estimation.

Secret key generation exploiting Ultra-wideband indoor wireless channel characteristics

Existing algorithms of secret key generation from Ultra-wideband UWB channels mostly exploited received signal strength to extract secret bits, however, this method is limited in key match probability. To investigate the issue, an efficient secret key generation mechanism using multipath relative delay is developed. Furthermore, a statistical characterization of UWB channels for a Chinese residential scenario is studied to simulate the proposed scheme. Simulation results demonstrate that our mechanism can achieve better performance in terms of common secret bit generation compared with the conventional method using received signal strength as a common random source, and the number of multipath proportionally affects key generation rate and key-mismatch probability. Additionally, for the first time, we verify key generation mechanism in both line-of-sight LOS and non-line-of-sight NLOS UWB channels. The results indicate that communicating transceivers have a slightly lower key-mismatch probability in NLOS condition than in LOS condition, as NLOS channels can provide a larger number of multipath. Copyright © 2014 John Wiley & Sons, Ltd.

Development of Wireless Patient’s Vital Sign Monitor Using Wireless LAN (IEEE.802.11.b/g) Protocol

Vital sign monitor is typical medical instrument for basic physiological measurement. Medical practitioner assesses a patient’s health condition by observing measurement results shown in display. In this research, we designed low cost, wireless, PC-based vital sign monitor. Signals captured in designed vital sign monitor are electrocardiogram (ECG), photoplethysmogram (PPG), and body temperature. Captured data are transmitted via wireless LAN module so that medical practitioner is able to monitor patient’s condition remotely from another room or place. The system worked well for maximum transmission distance about 45 meters for LOS condition and 20 meter for NLOS condition. DOI: http://dx.doi.org/10.11591/ijece.v4i6.6429

A TOA Location Method Using ROS Scattering Model in NLOS Environment

In most cellular propagation environments, a LOS propagation path does not exist to all of the BSs that participate in locating a target MS. The signal received by the receiver is a multipath and interference mixed signal, which is NLOS signal. In NLOS conditions, the traditional location algorithms perform poorly. Therefore, a scattering-model-based location method for cellular network was proposed in this paper. Based on the Ring of Scatters (ROS) model, with the use of the mean value of the TOA measurements, the method mitigated the effects of NLOS.

NLOS 상태 추정을 이용한 위치 정보 신뢰성 기반의 정밀 위치 측정 시스템

이동형 장치의 위치 정보를 확보하기 위해 다양한 위치 측정 시스템이 연구되고 있으며 현재 가장 많이 이용하는 시스템은 위성 정보를 이용하는 GPS와 무선 네트워크를 이용하는 RTLS가 있다. 장치 주변의 장애물은 장치와 위성 혹은 무선 통신 앵커와 NLOS 상태를 유발하며 측정 정확도를 떨어뜨린다. 본 논문에서는 대상의 위치 측정을 위해 두 개의 시스템을 함께 이용해 장치 주변의 NLOS 상태를 파악하여 장치간의 측정 신뢰성 정보를 추정함으로써 측위 정확도를 향상시키는 기법을 제안한다. 또한 NLOS 상태의 파악을 위한 위성 정보의 분석 방법에 대해서 설명하고 이를 이용한 위치 측정 시스템을 제안한다. 본 시스템의 성능평가를 위해 다양한 환경에서의 NLOS 상태 판별에 대한 테스트를 수행하였으며 해당 측정결과를 이용한 위치 측정 시스템을 구현하여 시뮬레이션 하였다. NLOS 상태 파악을 위한 실험 결과 약 97% 정도의 성공률로 NLOS 상태를 판별하였다. 또한 NLOS 상태 판별 정보를 이용한 동작 성능을 모의실험한 결과 단독으로 위치 측정한 결과에 비해 성능이 89% 향상되는 것을 확인하였다. Recently, mobile devices were increased and there was a sharp rise in demand. To exploit the location information of each device, many researcher was studying locating systems. The favorite locating or positioning systems were a GPS using satellites and a RTLS using wireless communication between devices. If some obstacle existed nearby the target device, The system have difference of performance. The obstacles near targets were caused signal disconnection and reflection because of NLOS condition. As the result, the NLOS condition degrade the locating performance. In this paper, we propose a locating system which is cooperated two systems using information reliability estimates from LOS/NLOS condition. We developed proposed system. In addition, we performed fields test and simulation tests at various environment for performance evaluation. As the result, the test showed 97% success rate to estimate NLOS condition. Furthermore, the simulation result of our locating system was increased to 89% compared with a single system.

Analysis of TDOA based radar target positioning in LOS and NLOS environments

We present the analysis of a radar target positioning technique in both Line-of-Sight LOS and Non-Line-of-Sight NLOS environments. A Time-Difference-of-Arrival TDOA method is investigated to find the target position and its positioning accuracy in terms of the Cramer-Rao Lower Bound CRLB. Explicit analytical results are derived under both the only LOS condition and the mixed LOS and NLOS condition. Numerical examples are provided for further quantitative evaluation.

AN ADVANCED UWB CHANNEL MODEL FOR BODY-CENTRIC WIRELESS NETWORKS

This paper presents a novel ultra wideband (UWB) channel model in the 3{10GHz range for body-centric wireless communications. The tests are performed in both indoor anechoic chamber environments, addressing on-body and ofi-body propagation scenarios. The body channel model is extracted by using a single spatial grid over all the body, and by distinguishing between LOS and NLOS condition. The large number and the uniform placement of the receiver locations attempt a representation of the body propagation links more comprehensive than previously published models. The statistical reliability of the model is investigated by applying jointly the Kolmogorov-Smirnov and the Akaike criteria. The analysis suggested that the Lognormal model flts the channel amplitude distributions with a percentage ‚ 64%. The on-body indoor channel amplitudes are modeled with a stochastic terms of about 4{5dB higher than previously published models. Finally, a Negative-Binomial and Inverse Gaussian distribution are used to model the expected number of paths and interarrival time, respectively. Based on the results presented in this paper, clear recommendations are given with regards to the optimum statistical distribution of an accurate UWB body-centric radio channel modeling.

WiMAX Technology can offer Coverage in Both LOS and NLOS Conditions

WIMAX technology can provide coverage in LOS and NLOS conditions, NLOS has many implementation advantages that enable operators to deliver broadband data to wide range of customer, WIMAX technology has many advantages that allow it to provide NLOS solutions, with essential feature such as OFDM technology, adaptive modulation and error correction. WIMAX has many optional features, such as ARQ, sub-channeling, diversity and space-time coding, It will prove invaluable to operators wishing to provide quality and performance that rivals wireline technology. WiMAX’s advanced technology provides the best of both worlds’ large coverage distances of up to 50 kilometers under LOS conditions and typical cell radii of up to 5 miles/8 km under NLOS conditions. Keywords: LOS, NLOS, WiMax, CPE, Base Station, OFDM, Sub-Channelization, Directional antennas

A Dual-Linearly-Polarized MEMS-Reconfigurable Antenna for Narrowband MIMO Communication Systems

The design and characterization is described of a compact dual-linearly-polarized reconfigurable 2-port antenna. The antenna can operate in two different selectable linear polarization bases, thus being capable of reconfiguring/rotating its polarization base from vertical/horizontal (0°/90°), to slant ±45°. The antenna has been implemented on a quartz substrate, and uses monolithically integrated micro-electromechanical (MEM) switches to select between the two aforementioned polarization bases. The antenna operates at 3.8 GHz and presents a fractional bandwidth of 1.7%. The interest of the proposed antenna is two-fold. First, in LOS scenarios, the antenna enables polarization tracking in polarization-sensitive communication schemes. Second, there are the gains of using it in a multiple-input multiple-output (MIMO) communication system employing orthogonal space-time block codes (OSTBC) to improve the diversity order/gain of the system in NLOS conditions. These benefits were verified through channel measurements conducted in LOS and NLOS propagation scenarios. Despite the simplicity of the antenna, the achievable polarization matching gains (in LOS scenarios) and diversity gains (in NLOS scenarios) are remarkable. These gains come at no expenses of introducing additional receive ports to the system (increasing the number of radio-frequency (RF) transceivers), rather as a result of the reconfigurable capabilities of the proposed antenna.

Unified approach to predicting cellular characteristics in urban environments with rectangular grid‐plan streets

This work presents theoretical predictions obtained by Blaunstein et al. [1997], Blaunstein and Levin [1996], Walfisch and Bertoni [1988], Xia et al. [1993], Xia and Bertoni [1992], and Bertoni et al. [1994] for estimating microcell characteristics in a street environment in order to improve the effective service to individual subscribers to cellular wireless systems. In the case when the investigated region is built in a grid‐like manner with regularly distributed rows of buildings and both antennas are located under the average building height in conditions of line of sight (LOS) along the street, we use the model of a three‐dimensional (3‐D) multislit waveguide, according to Blaunstein et al. [1997] and Blaunstein and Levin [1996], to estimate the path loss at the street level. In the case of obstructive (NLOS) conditions, when both antennas are placed below and above the rooftops in an environment with strong shadowing surrounding them, we use the 2‐D model of multidiffraction from the building roofs and walls, according to Walfisch and Bertoni [1988], Xia et al. [1993], Xia and Bertoni [1992], and Bertoni et al. [1994], modified in conjunction with actual variations of building heights, the distances between them, and the actual base station antenna height variations; at street intersections we use the crossing‐waveguide model according to Blaunstein and Levin [1997]. The contributions to path loss are obtained to predict the experimentally observed coverage effects and a cell radius in LOS and NLOS conditions to predict the microcell shape for cellular map construction in urban and suburban areas with regularly distributed rows of buildings and rectangularly crossing streets.

Prediction of cellular characteristics for various urban environments

The propagation channel for UHF/X-band waves in the city is modeled for two typical cases in the urban scene: (a) by regularly distributed rows of buildings placed on a flat terrain; and (b) by an array of randomly distributed buildings placed on rough terrain. The law of distribution of buildings in both cases is assumed to be Poisson. The loss characteristics in such urban propagation channels, as well as the co-channel interference parameter, the carrier-to-interference ratio (C/I), are investigated. In case (a), the three-dimensional multi-slit waveguide model is used for LOS conditions, and the two-dimensional multi-diffraction model is used for NLOS conditions. In case (b), the statistical parametric model of wave propagation is used, including single and multiple scattering effects, diffraction from buildings' roofs, the actual built-up relief, and various positions of receiver and transmitter antennas on rough terrain. The full algorithm for predicting propagation and cellular characteristics to increase the accuracy of radio and cellular maps is presented.

Applications of the Hahn-Banach Theorem in Approximation Theory

Applications of the Hahn-Banach Theorem in Approximation Theory