Radio Zone Research Articles

Method of Calculating the Boundaries of the Active Protection Mobile Radio Zone

Method of Calculating the Boundaries of the Active Protection Mobile Radio Zone

On the possibility of organizing communication for e-Navigation in the coastal zone using radio-technical posts of the vessel traffic control system

The concept of e-Navigation is to unify activities for the collection, integration, exchange, presentation and analysis of information on vessels and in coastal services through electronic technologies to improve the navigation safety, and the quality and efficiency of the relevant services.The generalized analysis of the obtained data is used to determine the appropriate actions in the prevailing conditions, to improve the process of the vessel’s transition from berth to berth (in ports of departure and destination) and the corresponding services that ensure the safety of navigation, environmental protection, information exchange between intelligent transport systems.The basis for fulfilling the assigned tasks are three basic components of e-Navigation: vessel systems; coastal and satellite systems; communication infrastructure. The purpose of the paper is the possibility of applying broadband radio communications for unmanned navigation in the coastal zone. The research object is the analysis of broadband communication systems; the subject is the assumed range of the WiMAX radio communication zone. EMC Planner 1.1_170328 is used to simulate the anticipated WiMAX radio zone.

Digital Vulnerability: The Unequal Risk of E-Contact with the Criminal Justice System

Increased citizen interaction with the criminal justice system on digital platforms renders citizens more vulnerable to breaches of information to third parties. We introduce the concept of digital vulnerability to measure the extent to which technology produces unequal exposure to risk of data breaches. Using police-dispatcher radio communication, we examine the extent to which dispatchers reveal identifiable information about callers reporting crime. Data come from sixty audio-recorded hours of police-dispatcher radio communication across three racially distinct police radio zones in Chicago. Findings revealed that one of every ten calls made to police in zones serving racial minorities disclosed caller names or home addresses. We discuss implications for research on racial inequality in criminal justice contact, police-community relations, and policies concerning police-dispatcher radio communication.

Experimental Investigations of Cochannel Interference Reduction Effect at High Elevation Base Station Using Beam Tilt and Orthogonal Polarization

This paper addresses the problem of cochannel interference (CCI) generated in a mixed cell architecture in microcellular systems. In this type of microcellular systems in which both microcells and macrocells coexist in the same geographical urban area, the base station antennas mounted on the rooftops of buildings to cover wide circular radio zones suffer severe CCI from the surrounding low base stations. A dielectric-loaded slotted-cylinder antenna (DSCA) is applied to horizontally polarized omnidirectional array antennas in a height-diversity configuration with the high gain of 8 dBi, which is comparable to that of a collinear antenna, to reduce the CCI. The measurements conducted in a suburban area clarify the reduction in the CCI for three techniques. The beam-tilt technique reduces the CCI level by approximately 10 dB for both collinear antennas and the DSCA array antennas. The use of horizontal polarization reduces the CCI level by approximately 13 dB for the DSCA array antennas with and without beam tilt. The combination of the beam tilt and horizontal polarization or the DSCA array antennas with beam tilt significantly reduces the CCI level by approximately 23 dB.

A new perspective on the radio active zone at the Galactic center – feedback from nuclear activities

AbstractBased on our deep image of Sgr A using broadband data observed with the VLA† at 6 cm, we present a new perspective of the radio bright zone at the Galactic center. We further show the radio detection of the X-ray Cannonball, a candidate neutron star associated with the Galactic center SNR Sgr A East. The radio image is compared with the Chandra X-ray image to show the detailed structure of the radio counterparts of the bipolar X-ray lobes. The bipolar lobes are likely produced by the winds from the activities within Sgr A West, which could be collimated by the inertia of gas in the CND, or by the momentum driving of Sgr A*; and the poloidal magnetic fields likely play an important role in the collimation. The less-collimated SE lobe, in comparison to the NW one, is perhaps due to the fact that the Sgr A East SN might have locally reconfigured the magnetic field toward negative galactic latitudes. In agreement with the X-ray observations, the time-scale of ∼1 × 104 yr estimated for the outermost radio ring appears to be comparable to the inferred age of the Sgr A East SNR.

Determining a radio signal consistent reception zone within cell boundaries under urban conditions

The cell part of a cellular mobile communication system is determined where the radio signal level exceeds the reception threshold value with allowance for multibeam radiowave propagation (with the Rayleigh fading distribution).

A Study of Radio Zone Length of Dual-Polarized Omnidirectional Antennas Mounted on Rooftop for Personal Handy-Phone System

This paper proposes a dual-polarized omnidirectional antenna for base-station antennas that are mounted on the rooftops of buildings. The antenna suppresses the degradation in the received-signal level due to the inclination of mobile antennas in the personal handy-phone system (PHS). The proposed polarization-diversity antenna is comprised of a dielectric-loaded slotted-cylinder antenna for horizontally polarized waves and a conventional collinear array antenna for vertically polarized waves in a height-diversity configuration. The structure of the proposed antenna and its fundamental characteristics, such as the input impedance and radiation pattern, are shown. The change in the radio zone length (RZL) due to the inclination angle of the mobile antenna is measured to estimate the improvement offered by the proposed antenna in an urban area. It is shown that the RZLs of the collinear antennas in line-of-sight (LOS) environments are decreased by 73% when the mobile antenna is inclined at 90 , whereas the proposed polarization-diversity antenna restrains the degradation to approximately 20%, regardless of the inclination angle without downtilt and from 20% to 40% for a 15 downtilt. The RZLs of the collinear tilt antennas in non-LOS (NLOS) environments are below approximately 20%, compared to those of the collinear tilt antennas for the LOS route. We show that the RZLs in the NLOS environments are short compared to those for the LOS environments in microcell systems such as PHS with a high-elevation base station, even when the polarization-diversity technique is applied to the base station.

New Method for Evaluating Height Gain at Subscriber Station for Wireless Access Systems in Microwave Band

This paper presents a model for the variation in height of the subscriber station (SS) antenna with respect to the path loss for microwave-band wireless access systems. The propagation mechanism that causes the dependency of the height variation characteristics of the received level at an SS on the SS location and operating frequency is clarified in terms of geometrical optics (GO) using the uniform geometrical theory of diffraction (UTD). The height variation characteristics strongly depend on whether or not regular reflected waves that have a higher level than that of the diffracted wave arrive at the SS. A representation of the model is shown. The model is validated using measured data at 2.2, 5.2, and 25.15 GHz and the validity of the model is shown. This model is useful in the radio zone design of microwave-band broadband wireless access (BWA) systems operating in a non-line-of-sight environment, and in estimating the height gain at a mobile station antenna for mobile communications.

Propagation characteristics in an underground shopping area for 5‐GHz‐band wireless access systems

Abstract5‐GHz‐band wireless access systems, such as the RLAN (Radio Local Area Network) system of IEEE 802.11a, HiperLAN/2, HiSWANa, and AWA, are deployed for indoor use at transmission rates over 20 Mbps. These 5‐GHz access systems are expected to extend service areas from the office to the so‐called “hot spots” in public areas. Underground shopping malls are one type of service area where the application of such nomadic wireless access service can be expected. In order to design radio zone configurations, it is necessary to know broadband propagation characteristics of an underground mall environment even if results obtained by previous measurements in the narrow band are available.This paper presents results of an experimental study on the propagation characteristics for broadband wireless access systems in an underground mall environment. First, broadband propagation path losses are measured and formulated considering the shadowing by human body. A ray trace simulation is used to clarify the basic propagation mechanism in such a closed environment. Next, it was determined that values of the delay spread at different distances during rush hour periods did not exceed 65 ns, which is lower than the permitted maximum value of the present 5‐GHz systems. The final conclusion is that the above propagation characteristics corroborate results of transmission tests carried out by using the AWA equipment. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 55–64, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20059

Mobile communication system having a control station which selects speech coding schemes for a mobile station

Communication is carried out on the basis of an optimum speech coding scheme that is matched to the speech coding schemes provided by the radio zones, and to the speech coding capabilities of the mobile stations. To achieve this, when a traffic channel is set up between a mobile station and a switch, a traffic channel selection condition that has been specified by the switch on the basis of the speech coding capabilities of the mobile station that made the SETUP request and of the mobile station to which the call is made, is stored in the control station. The control station grasps which speech coding scheme is currently being used in the radio zone which it controls. Moreover, by transferring the selection conditions specified by the switch and using these conditions as information required for channel setup by another control station, communication can be carried out using a high-priority speech coding scheme when handover occurs. This happens when channel selection takes place in another radio zone spanning control stations, or when a mobile station has moved to a radio zone in which a high-priority speech coding scheme can be used. As a result, traffic channels based on the optimum speech coding scheme can be changed over smoothly.

A Direct Image of the Inner Torus of NGC 1068

We present the first VLBI observations of the compact source S1 in the radio jet of NGC 1068. Roughly 1 pc in length and 0.2 pc wide, S1 resolves into clumps aligned perpendicular to the local radio jet axis. The radio continuum emission arises from a hot (Te ~ 106 K), dense (ne ~ 106 cm-3) plasma, and the source of the radio emission is either thermal free-free emission or Thomson-reflected synchrotron emission. The clouds comprising S1 are opaque to soft X-radiation, and we therefore propose that S1 is the inner, ionized region, or ‘hot zone,’ of the obscuring medium surrounding the active nucleus. The covering fraction of the hot zone is small, Cf ⋦ 10%. Since the covering fraction of the dusty, obscuring medium is probably much larger, the obscuring disk must either flare or warp outside of the hot zone. That the radio jet and hot zone axes are perpendicular also suggests that the hot zone may be considered to trace the outermost extent of the accretion disk.

A mobile packet communication with a chained isolated radio zone network system

AbstractA mobile packet communication with a chained isolated radio zone network system is proposed that provides nonrealtime media services including voice messages, images, and navigation information, etc., to terminals in cars. In this system, microradio zones are located along a road to establish the communication between a radio base station and a terminal by using packets in a common format. A terminal receives the signal by the paging channel covering a wide area and transmits packets sequentially when a terminal passes radio zones. Therefore, only three radio frequencies, inbound, outbound, and paging channels, are enough and location registration of all terminals is not necessary to realize the proposed system. When transmission and reception of multiple packets is not completed in a single radio zone, it can be done in other radio zones. Since every terminal has a different staying time in each radio zone, the relationship between staying time and throughput, and the relationship between staying time and message transmission ratio are examined and evaluated by the simulation.

A method to place micro radio zones in mobile packet communication with a chained isolated radio zone network system

AbstractThe authors have already explored a mobile packet communication system for car drivers in which navigational information (maps, pictures, and voice) and stored information (voice message, facsimile, and data) could be sent by common format packets. Because the radio zones in these systems are isolated from each other, efficient use of radio frequencies is desirable. However, since traffic distribution and automobile speeds differ at different locations, the position and number of radiozones has a large effect on system efficiency. This paper describes a method in which radio zones are placed on a given route network by using a car traffic flow simulator that is applicable to mobile communication. Car motion and speed are simulated; the volume of traffic in each radio zone and the traffic that can be processed in each zone are calculated using a model that is quite close to an actual route network. These values are compared with transmission efficiency in a single radio zone. Radio zones are located by deleting existing radio zones that have had poor transmission; relevant results are then discussed.

Microtexture in the pulsar radio emission zone

This paper completes an analysis of a non-linear mechanism for pulsar radio radiation. This non-linear process results from the evolution of relativistic two-stream instability in the pulsar magnetosphere, which gives rise to strong Langmuir turbulence. There are stable Langmuir soliton-like solutions, called Langmuir microstructures, which may form a lattice in the magnetosphere. These Langmuir microstructures naturally produce three different types of radiation. The first is direct radiation of the microstructures themselves when perturbed in a direction perpendicular to the magnetic field lines

UHF band spatial correlation characteristics of mobile base station antennas

Spatial correlation characteristics of the base station antenna in a mobile propagation path have been studied in the past in the case where the antenna height is sufficiently greater than the average building height in the surrounding area. However, for effective use of frequencies, the base station antenna height may be reduced so that the radio zone can be made smaller. To this end, it is necessary to determine the method for computing the spatial correlation characeristics in the case where the base station antenna height is comparable to the average building height. In this paper, the arriving angle distribution of the multiple waves in an urban area is measured and the ration of the scattered wave level to the main arriving wave level is related to the antenna height and the antenna gain. Also, a method is proposed for deriving the spatial corrrelation coefficient by means of a and its usefulness is verified by measured results.

Discrete Minimal Radio Zone Communication System in RACS Project and its Performance Evaluation

A new type of road-automobile communication system called Discrete Minimal Radio Zone Communication System is now under development in Japan. The composition, technological characteristics and applicability of the system to navigation, traffic information, traffic management and route guidance are discussed. To evaluate the performance of the communication system, simulation studies using traffic data measured by detectors are carried out. The results of the simulations imply that the system is highly eligiable as a two-way communication link between road and vehicles to realize various objectives related to road traffic environment.

Location of mobile subscriber station on land mobile radio with MSSC

AbstractAs for radio channel control of a cellular mobile communication system, location measurement is an important technique for determining the base station to be Connected with the mobile station. This paper describes the radio zone selection characteristic when a part of the control channel is time‐shared by base stations and the reception level of each base station is measured at mobile stations. MSSC (Multitransmitter Simul/Sequential Casting) of control channels is proposed, which improves the location measurement and is suitable for a high‐capacity system. The MSSC channel consists of simul‐cast parts and sequential‐cast parts. Its speech connection control sequence when applied to the cellular mobile communication system is shown. Next, the relation between the reception level variation characteristic in land mobile communication and the average reception level measurement accuracy when burst signals are received several times is studied. Both analytical results and laboratory experimental simulation results are shown. Finally, the zone selecting rate of a mobile station is calculated and the effect of the proposed control channel configuration is clarified.

Mobile location using signal strength measurements in a cellular system

In a high-capacity mobile telephone system using cellular technology, a mobile location technique which determines the radio zone in which a moving vehicle exists is one of the most important techniques for the system control. A mobile location technique using a signal strength measurement scheme is described. The probability that a mobile is judged to exist in a certain zone (zone selection rate) is first defined. Dependency of this rate on land mobile propagation characteristics is then discussed in detail. A field test for the justification of this location technique was carried out in the Tokyo metropolitan area in which the field test results agreed well with the estimated values.

Multiple radio zone plans in mobile radio systems

Multiple zone structure in a land mobile system seems to offer a flexibility in radio zone planning by using different interference distances conforming to the different system requirements in a system, thus improving the frequency utilization. A multiple zone structure can be formed by a tessellation of basic zone groups with an identical shape in parallel translation on a plane. To assure the possibility of the tessellation, two types of basic zone groups are investigated. One has several hexagonally shaped zones covered by an omnidirectional antenna beam from the zone center, while another is constructed as a subdivision of hexagons covered by a directive antenna beam. The former is expected to facilitate reduced interference distance between adjacent frequencies. An estimate of the latter type has shown better frequency economy than that in a conventional zone structure.