Path Loss Exponent Values Research Articles

Path Loss Characterization in an Outdoor Corridor Environment for IoT-5G in a Smart Campus University at 850 MHz and 3.5 GHz Frequency Bands.

The usage scenarios defined in the ITU-M2150-1 recommendation for IMT-2020 systems, including enhanced Mobile Broadband (eMBB), Ultra-reliable Low-latency Communication (URLLC), and massive Machine Type Communication (mMTC), allow the possibility of accessing different services through the set of Radio Interface Technologies (RITs), Long-term Evolution (LTE), and New Radio (NR), which are components of RIT. The potential of the low and medium frequency bands allocated by the Federal Communications Commission (FCC) for the fifth generation of mobile communications (5G) is described. In addition, in the Internet of Things (IoT) applications that will be covered by the case of use of the mMTC are framed. In this sense, a propagation channel measurement campaign was carried out at 850 MHz and 5.9 GHz in a covered corridor environment, located in an open space within the facilities of the Pedagogical and Technological University of Colombia campus. The measurements were carried out in the time domain using a channel sounder based on a Universal Software Radio Peripheral (USRP) to obtain the received signal power levels over a range of separation distances between the transmitter and receiver from 2.00 m to 67.5 m. Then, a link budget was proposed to describe the path loss behavior as a function of these distances to obtain the parameters for the close-in free space reference distance (CI) and the floating intercept (FI) path loss prediction models. These parameters were estimated from the measurements made using the Minimum Mean Square Error (MMSE) approach. The estimated path loss exponent (PLE) values for both the CI and FI path loss models at 850 MHz and 3.5 GHz are in the range of 2.21 to 2.41, respectively. This shows that the multipath effect causes a lack of constructive interference to the received power signal for this type of outdoor corridor scenario. These results can be used in simulation tools to evaluate the path loss behavior and optimize the deployment of device and sensor network infrastructure to enable 5G-IoT connectivity in smart university campus scenarios.

Maximizing Signal Quality for One Dimensional Cells In Mobile Communications

In this work, the cellular network performance based on other cell interference predictions is presented. It presents a mathematical model of co-channel interference analysis in hexagonal and linear cell shapes through a log-distance propagation model to investigate the effect of path loss exponent value on the received signal quality of the downlink. Simulation results obtained show that as the power exponent value increase, the interfering signals attenuation is increased resulting in received signal quality improvement. The signal-to-interference ratio (SIR) received by subscribers close to the cell edge will be less due to the contribution of the near-interfering cells especially when multiple layers of interfering cells are considered. The simulations confirmed that the impact of multi tiers of interfering cells cannot be ignored in systems of small cluster size as they may contribute to system performance degradation.

Channel Analysis for 3.5 GHz Frequency in Airport

This letter presents an analysis of the radio propagation channel based on measurements at the 3.5 GHz frequency. The measurement campaigns were carried out inside the Valde-Cans airport using line-of-sight (LOS) transmissions. First, the channel small-scale dispersion parameters were extracted through channel probing and the results are similar to those obtained by ITU-R P.1238 for the bands below 15 GHz considering commercial indoor environments as well as for those using the 3.5 GHz band in outdoor environments utilizing WiMax OFDM-256 signals. Then, the floating-intercept (FI) and close-in (CI) models are applied and analyzed to evaluate the received signal behavior for co-polarized and cross polarized antennas. The results show that the CI path loss exponent values are close to the free space propagation loss model, while the FI model provides a lower root mean square error (RMSE) to the measured data. The results show that the FI and CI models are suitable for large-scale indoor propagation loss modeling for 5G networks with a frequency of 3.5 GHz.

Millimeter-Wave Channel Measurements and Path Loss Characterization in a Typical Indoor Office Environment

In this paper, a path loss characterization at millimeter-wave (mmWave) frequencies is performed in a typical indoor office environment. Path loss results were derived from propagation channel measurements collected in the 25–40 GHz frequency band, in both line-of-sight (LOS) and obstructed-LOS (OLOS) propagation conditions. The channel measurements were performed using a frequency-domain channel sounder, which integrates an amplified radio over fiber (RoF) link to avoid the high losses at mmWave. The path loss was analyzed in the 26 GHz, 28 GHz, 33 GHz and 38 GHz frequency bands through the close-in free space reference distance (CI) and the floating-intercept (FI) models. These models take into account the distance dependence of the path loss for a single frequency. Nevertheless, to jointly study the distance and frequency dependence of the path loss, multi-frequency models were considered. The parameters of the ABG (A-alpha, B-beta and G-gamma) and the close-in free space reference distance with frequency path loss exponent (CIF) models were derived from the channel measurements in the whole 25–40 GHz band under the minimum mean square error (MMSE) approach. The results show that, in general, there is some relationship between the model parameters and the frequency. Path loss exponent (PLE) values smaller than the theoretical free space propagation were obtained, showing that there are a waveguide effect and a constructive interference of multipath components (MPCs). Since the measurements were obtained in the same environment and with the same configuration and measurement setup, it is possible to establish realistic comparisons between the model parameters and the propagation behavior at the different frequencies considered. The results provided here allow us to have a better knowledge of the propagation at mmWave frequencies and may be of interest to other researchers in the simulation and performance evaluation of future wireless communication systems in indoor hotspot environments.

Simulation and Measurement of on-body and off-body Communication Propagation Channels by using dual-band Magnetic Antenna Textile

Evolution of Wireless Body Area Network (WBAN) in telemedicine field keep increased along with needs and enhancement of services, nevertheless an efficient and effective form of communication becomes essential for any type of wireless communication network. One of the most important parameter for designing communication network is path loss exponent. Based on that, the purpose of this research is to know the propagation characteristics for on-body and off-body communication by comparing the simulation and measurement using magnetic textile antenna at 2.45 GHz and 924 MHz with distance variation in LOS and NLOS conditions. In this research, friis formula is used to get the path loss exponent value that shows the characteristics of propagation. The calculation of path loss exponent value for simulation and measurement for on-body communication with LOS and NLOS conditions are between 1.7-1.9 while off-body with LOS and NLOS conditions are between 2.1-5.2. These results show that the body affects path loss exponents value and have own characteristics.

Path Loss and Channel Modeling at 3.5GHz for 5G Cellular System

Wireless channel characterization is the basis of the architecture of the wireless communication system. The detailed propagation models are indeed the requirement for fifth generation communication network design. This paper presents the characteristics of channel propagation for a fifth-generation system in Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) scenarios with co-polarization (V-V) and cross polarization (V-H) in a second floor/Communication Engineering Department/Electronics college building at 3.5GHz frequency. The comparison between two path loss models shows that the Close-In (CI) of free space reference distance path loss model is more suitable than Floating-Intercept (FI) path loss model. The results of both models show that the path loss exponent value (n) is ranged between 1.7 and 2.9 for the LOS scenario, while it was between 2.1 and 3.1 for NLOS scenario for both co-polarization and cross polarization.

Variations of GSM Path Loss Exponent with Propagation Distance at L-Band Frequencies in Different Microcellular Environment of Southwestern Nigeria

Propagation path loss exponent is an important component of system design, and knowing the values helps to avoid surprises when the actual service begins. The path loss exponent is known to be critical in establishing the coverage of any new cellular network. Estimating the path loss exponent of any environment requires raising new data sets, which can be accomplished by conducting experiments. With this objective, the present study reports the L-band signal RSS level measurements of 6 GSM base stations in the urban, suburban and rural environments of Ondo and Ekiti States in the Southwestern region of Nigeria. Using a Sony Ericsson TEMS phone monitoring device—connected to a laptop equipped with TEMS software and base station cell reference—and a GPS device, RSS measurements were performed in each sector of the base station up to 1200 m, employing a single sector verification method. The values of path loss exponents were computed from the deduced values of path loss at 50 m intervals up to distances of 1200 m. Close to the base station, the following exponent values were observed—between 2.0 and 3.8 in the urban environment, 2.0 to 2.8 in the suburban environment while for the rural environment, 1.5 to 2.6 we're observed. After the breakpoint distance, higher path loss exponent values of up to 6 was recorded in the urban environment, exponent value of up to 4.3 was observed in the suburban environment and up to 3.5 exponent value in the rural environment. It was also observed that the rural environment presented the longest breakpoint distance of 500 m. The high path loss exponents observed, especially in the urban environment, could cause GSM operators to rethink the margins they have provided. This study is useful for the design of upcoming network systems in these regions and in similar regions.

Developed channel propagation models and path loss measurements for wireless communication systems using regression analysis techniques

BackgroundThe development of powerful and flexible management addresses is due to the improvement of deeply reliable gadgets and the advancement of the concept of cellular. The cellular principle was a major way of solving the wavelength crowding problem and the user capacity. It offered high capacity without major technological changes with limited allocation in spectrum. Wireless communication is an innovation in media transmission that allows remote transmission in all types of terrain between convenient gadgets. For estimating a transmitter 's radio coverage area, propagation models that anticipate the mean signal strength for an arbitrary transmitter–receiver separation distance are crucial as they are called large-scale propagation models so even though they define the average signal strength over long periods of time and large distances from the transmitter.ResultsDeveloped propagation models are presented according to the measured path loss values in exemplary urban and suburban areas at the operating frequency of 3.5 ghz by using the regression analysis. The measurements are implemented by using a spectrum analyzer FSH6 to get the channel response as shown in the stated tables and graphs. Based on the obtained results, it was observed that the path loss could be calculated as a function of distance and during the practical measurements 32 m was precise as a presumption for the break point distance. The values of path loss exponent (n) are defined and calculated for both of urban and suburban regions. Measurements results are analyzed and compared in order to study their influence for every specific environment. It was noticed that any radio signal will suffer attenuation when it travels from the transmitter to the receiver as a variety of various phenomena give rise to this radio path loss.ConclusionsThe interaction between both the electromagnetic radiation and the environment tends to decrease the quality of the signal being sent from the transmitter to the destination which causes the loss of the path. Propagation models are the basis for channel estimation, as they attempt to identify how a radio transmission changes from the transmitter to the receiver throughout its path. The gained results from this research will be supportive for the arrangement of network planners and researchers as proof and directory materials before future location establishment.

One‐to‐one non‐linear transformation for RSS‐based localization with unknown transmit power

For most of the positioning algorithms, based on the received signal strength, the objective function of the estimator is linearized so that the conventional least square algorithm can be executed. This would necessitate using a data model containing many noisy elements which implicitly violates the least squares assumptions. To avoid this violation, an optimized data modelling would have to be set up as shown in this paper. The authors then trivially provide the solution of this new least square problem which is still a primary coarse position estimation because of ignoring the non-linear relationships existing among parameters of the estimation. To extract quantitative information from these non-linear relationships, the authors also propose two new signal space points for using Taylor-series expansion as effectively as possible in accordance of the new data model. The proposed algorithms work without any knowledge about the transmit power. The performance evaluation of the proposed idea indicates that the new suggested estimators perform significantly better than the other existing linear position estimators for a large range of noise variance and path-loss exponent values.

Dynamic optimized cooperation in multi‐source multi‐relay wireless networks with random linear network coding

The authors present a strategy that improves the reliability of data transmission from multiple sources towards a destination D via multiple relays over wireless channels. After the broadcast phase, the destination selects the best cooperative direct link sources with the highest instantaneous signal-to-noise ratio , then generates and sends the random linear network coding coefficient matrix to the relays. After receiving the random linear network coding–coded symbols (packets) from the relays, D completes the reception and decoding of all source nodes packets. Monte Carlo simulations are conducted with Galois field (GF) () symbols ( = 2, 4 and 8) and the results are compared with the scenario of static cooperative direct links. An important decrease of symbol error rate (SER) is achieved. Furthermore, the efficiency of this approach is confirmed for the whole range of possible values of path loss exponent on direct links, that is, all types of environment between source nodes and destination D.

Path Loss Characterization in an Indoor Laboratory Environment at 3.7 GHz in Line-Of-Sight Condition

The objective of this work is to propose experimental path loss propagation models for communication channels in indoor environments. In this sense, an experimental path loss characterization has been achieved, according to the measurements campaign carried out in a typical scenario of a university campus. These narrowband measurements were collected in the laboratory environment at 3.7 GHz in line-of-sight (LOS) condition. Also, these measurements were carried out at night to simulate stationary channel conditions. Thus, the results obtained show the values of the parameters of the close-in (CI) free space reference distance and floating-intercept (FI) path loss models, in terms of the transmitter and receiver separation distance. It should be noted that these values of the path loss models have been extracted applying linear regression techniques to the measured data. Also, these values agree with the path loss exponent values presented by other researchers in similar scenarios. The path loss behavior can be described with the implementation of these models. However, more measurement campaigns are needed to improve the understanding of propagation channel features, as well as to obtain better precision in the results obtained. This, in order to optimize the deployment and performance of next fifth-generation (5G) networks that combine indoor environments to offer their services and applications.

Network Planning for Deep Fading Area at 1.8 GHz LTE Network

In the current scenario path loss, coverage and capacity by operating network under fading condition is research challenge. In this paper, signal strength of long term evolution network operating at 1.8 GHz is recorded for analysis. During the measurement, the range of received signal strength varies in between − 72 and − 104 dBm for basement data transmission. The variation of received signal at 12 distinct points in the basement was marked sincerely. Based on this received signal the link budget is formulated and presented. The capacity of a network on given link budget is calculated and verified. The data recorded for such environment using spectrum analyzer and simulating with Matlab is presented. The behaviour of signal referred to a value of path loss exponent i.e. 4.55. The path loss exponent provides the real coverage under urban area in fading condition. Using different models of prediction, real path loss under fading is calculated and based upon this path loss value a model is proposed for next generation networks.

Body-to-Body Channel Characterization and Modeling Inside an Underground Mine

In this article, the use of circularly polarized multiple-input–multiple-output (MIMO) antenna systems is proposed as a new solution for future body-to-body (B2B) applications. Four B2B channels have been characterized inside a mine. The statistical parameters of the B2B channels using co-positioned (CP) and 90° rotated (90R) antennas have been determined. Path loss (PL) exponent values varied between 2.33 and 1.26. The time dispersion parameters and channel capacities are computed for both CP and 90R scenarios. Moreover, channel correlation matrices and the Rician K-factor have been determined and discussed in terms of their effect on capacity and root mean square (rms) delay spread. Overall, the circularly polarized setup exhibits the best performance in terms of PL, rms delay spread, and channel capacity. The nonline-of-sight (NLOS) situation caused a significant drop in channel capacity due to the significant increase in PL, and an increase in the rms delay spread due to the multipath richness. The MIMO-NLOS scenario exhibits the highest throughput gain of 1.752 (at an SNR of 20 dB), due to its low branch correlation. A model of the B2B impulse response has been created based on a statistical–empirical approach to determine the optimal path amplitudes and time of arrival.

Effects of Solar Radio Emissions on Outdoor Radio Propagation at 38 GHz Bands for D2D Communications

This letter presents empirical data documenting the effects of solar radio emissions on outdoor radio propagation at 38 GHz millimeter-wave (mmWave) band for both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. Comparing the measurement data collected during a sunny day with the counterpart data collected at night, higher path loss exponent (PLE) values were observed during the day compared to nighttime. This is attributable to the decrease in the carrier-to-noise ratio for day-time signal propagation in sunny sky compared to nighttime. About 4% and 25% increase in PLE values was observed during the day for LOS and NLOS scenarios, respectively. This translates into corresponding decrease in the radio coverage of the wireless transmitter during the day compared to nighttime. Time-domain waveforms were also examined, and it was found that the average received signal envelope was 103 times below a given threshold during the day, and 19 times below the same threshold at night. This, thus, shows that the received signal envelope fades out many more times during the day compared to nighttime.

Channel Path-Loss Measurement and Modeling in Wireless Data Network (IEEE 802.11n) Using Artificial Neural Network

Careful network planning has become increasingly critical with the rising deployment, coverage, and congestion of wireless local area networks (WLANs).This paper investigates and determine the Path-loss exponent value for the ubiquitous wireless local area network at the Federal University Oye-Ekiti for the line of sight and non-line of sight (N-LOS). Aside this, the paper also models the wireless network using artificial neural network (ANN) technology by training some neurons based on data collected from a drive-test.
 The proposed ANN model performed with accuracy and is offered as a simple, yet strong predictive model for network planning – having both speed and accuracy. Results show, that for the area under study, Oye Campus has a higher standard deviation of 5.76dBm as against ikole Campus with 1.44dBm, this is because of dense vegetation at Oye Campus.
 In view of this, the paper provides a predictive site survey for rapid wireless Access point deployment.

Investigation of indoor propagation of WLAN signals

<p>The propagation of radio waves inside a typical university building is investigated by simulation and measurements. The Line of sight (LOS) and Obstructed Line of sight (OLOS) propagation scenarios were considered. The received power from a WLAN access point operating at 2.45GHz was determined from the simulations and measurements at various positions, orientations, and heights of the Tx and Rx antennas. The path loss exponents were estimated from the obtained simulation and measurement results of the received power variation with distance. The obtained path loss exponent values were found between 1.15-1.63 for LOS propagation and 2.14-2.55 for OLOS.</p>

Radio-propagation measurements and modeling in indoor stairwells at millimeter-wave bands

A good understanding of signal wave attenuation along a stairwell is necessary for successful wireless network planning. In this study, the propagation characteristics in indoor multi-floor stairwell environments are examined under the millimeter frequency band. An extensive signal measurement is conducted in two stairwells. These measurements provide information important for ensuring consistent radio transmission of data in such environment, which then enables immediate response during emergency operations. In these measurements, directional horn antennas for co-polarization and cross-polarization in transmitters and receivers are used for different millimeter frequencies (26, 28, 32, and 38 GHz). The feasibility of using the millimeter wave, which is suitable for indoor 5G wireless networks, in two different indoor stairwell environments is investigated. Four different models are employed for path loss investigation. Under single frequencies, the close-in free-space reference distance and floating-intercept path loss models are adopted. For multiple frequencies, the close-in free space reference distance with frequency dependent path loss exponent and alpha-beta-gamma models are applied. The measurements provide data on the received power at multi-floor stairwells through the stair steps, which are useful for path loss study. Accordingly, the path loss exponent values, standard deviations, and other parameters are obtained.

Capacity of UAV Relaying Networks

Unmanned aerial vehicles (UAVs), benefit by low cost, fast deployment, and large coverage, are widely applied as aerial relays in providing communication services for the areas with heavy traffic load or disasters. In this paper, the capacity of UAV relaying networks is studied, where the UAVs act as relays for the ground users. Two scenarios of UAVs distributed on an aerial 2-D plane and in a 3-D space are studied. The analysis reveals that in order to control the air-to-ground interference, the altitude of UAVs is at most in the same order to the distance between two adjacent UAVs. Besides, it is discovered that the pathloss exponent value α = 2.5 is a watershed for the capacity of UAV relaying networks, i.e., when α ≤ 2.5, the capacity of UAV relaying networks with the 2-D deployment of UAVs is greater than that with the 3-D deployment of UAVs. Otherwise, the capacity of UAV relaying networks with the 3-D deployment of UAVs is larger than that with the 2-D deployment of UAVs. Furthermore, the mobility of UAVs is studied, and it is verified that the mobility can orderly improve the capacity of UAV relaying networks. The theoretical analysis of this paper provides a guideline for the deployment of UAVs as aerial relays.

Path Loss Model for Outdoor Parking Environments at 28 GHz and 38 GHz for 5G Wireless Networks

It has been widely speculated that the performance of the next generation Internet of Things (IoT) based wireless network should meet a transmission speed on the order of 1000 times more than current wireless networks; energy consumption on the order of 10 times less and access delay of less than 1 ns that will be provided by future 5G systems. To increase the current mobile broadband capacity in future 5G systems, the millimeter wave (mmWave) band will be used with huge amounts of bandwidth available in this band. Hence, to support this wider bandwith at the mmWave band, new radio access technology (RAT) should be provided for 5G systems. The new RAT with symmetry design for downlink and uplink should support different scenarios such as device to device (D2D) and multi-hop communications. This paper presents the path loss models in parking lot environment which represents the multi-end users for future 5G applications. To completely assess the typical performance of 5G wireless network systems across these different frequency bands, it is necessary to develop path loss (PL) models across these wide frequency ranges. The short wavelength of the highest frequency bands provides many scatterings from different objects. Cars and other objects are some examples of scatterings, which represent a critical issue at millimeter-wave bands. This paper presents the large-scale propagation characteristics for millimeter-wave in a parking lot environment. A new physical-based path loss model for parking lots is proposed. The path loss was investigated based on different models. The measurement was conducted at 28 GHz and 38 GHz frequencies for different scenarios. Results showed that the path loss exponent values were approximately identical at 28 GHz and 38 GHz for different scenarios of parking lots. It was found that the proposed compensation factor varied between 10.6 dB and 23.1 dB and between 13.1 and 19.1 in 28 GHz and 38 GHz, respectively. The proposed path loss models showed that more compensation factors are required for more scattering objects, especially at 28 GHz.

Path loss model for indoor emergency stairwell environment at millimeter wave band for 5G network

The unused millimeter-wave (mmWave) spectrum offers a superb opportunity to increase mobile broadband capacity due to the enormous amount of available bandwidth. Different candidate operating frequencies for 5G wireless networks are available at the mmWave band. For 5G wireless networks, the emergency case is one of the applications. This paper presents the outcome of indoor emergency stairwell measurement campaigns for 5G system at 26 GHz, 28 GHz, 32 GHz, and 38 GHz, which were conducted at the University Technology Malaysia, Kuala Lumpur, Malaysia. To effectively evaluate the performance of 5G wireless systems in these different bands, single- and multifrequency path loss models are proposed for this environment. This paper proposes a new path loss model based on a new physical anchor point referred to as physical-anchor stair (PAS) path loss model. In a single-frequency large-scale case study, the PAS and the floating intercept (FI) path loss model are investigated at the 20 GHz and 30 GHz bands. Moreover, this study is extended to cover the multifrequency path such as the alpha, beta, and gamma model and the close-in free space path loss model with frequency weight (CIF) model. The CIF model is developed in this paper. The proposed PAS model shows high accuracy (physically based model) and less complexity compared with the studied models. Results show that the path loss exponent values vary between 6.6 and 7.9 for all measured frequencies using the proposed PAS model and between 9.1 and 10.9 using the FI model.