An approach to estimating land mobile radio coverage

This paper reports some propagation and coverage prediction results using various models provided to the Federal Communications Commission, Spectrum Management Task Force.     

A design concept for reconfigurable mobile radio networks with slowfrequency-hopping signaling

A design concept to support both the initial planning and the management of land mobile radio networks with slow frequency-hopping signaling is proposed. It is applicable to the networks with advanced architecture of which the Pan European networks may be an example. The design consists of two planning processes: spatial and frequency planning. A novel heuristic is used to optimize the base station locations with respect to the total interference-to-signal ratio in a network. This ensures economic coverage of the network service area as well as efficient frequency reuse. A repeated application of the same heuristic to the currently measured and/or predicted data offers powerful means to manage a network in order to keep its resources highly available to their users, as is shown in a simulation example which includes not only sources of unintentional (cochannel, adjacent channel, and intermodulation) interference but also sources of intentional (jammer) interference     

The simulcasting technique: An approach to total-area radio coverage

The simulcasting technique described provides total-area radio coverage on an automatic basis where the use of multiple transmitter and receiver sites is required to achieve acceptable communications coverage over rugged terrain or wide areas. In this technique the same audio information is simultaneously broadcast over several transmitters operating on a single nominal-carrier frequency. Special attention must be given to transmitter-frequency stability and audio envelope characteristics. A master tone-distribution system is essential when incorporating a continuous tone-controlled squelch system (CTCSS). Use of the simulcasting technique reduces effects of fading in a mobile environment through transmitter space diversity. An application of the simulcasting technique to a coordinated FM-UHF law-enforcement communications system in Orange County, CA, is described.     

An unified numerical approach for computing the outage probabilityfor mobile radio systems

A general finite-range integral for the probability of outage in mobile radio systems is derived. The method handles noninteger Nakagami-fading indices, unequal Rice factors, unequal shadowing spreads, and unequal transmitted powers as well as all the common fading distributions (Rayleigh, Rice, Nakagami-m, Nakagami-q, lognormal-Rice, Suzuki, and lognormal-Nakagami-m). The integral expression can also be approximated by a Gauss-Chebychev quadrature (GCQ) formula requiring knowledge of the moment generating function at only a small number of points. An estimate of the remainder term is also derived. This numerical technique allows computing the outage with arbitrary precision and it is extremely easy to program     

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.     

Land mobile radio systems in Poland

The current situation of land mobile radio (LMR) systems in Poland is described. This includes paging, dispatch, trunking, and cellular systems. Frequency plan and organization of LMR communication in Poland are presented. Finally, the plan for the future development of LMR systems in Poland, prepared by the Ministry of Telecommunications, is summarized     

A practical approach to radio propagation measurements—As used in the design of mobile radio communications systems

The design of a mobile or portable radio communications system requires the consideration of a number of unique engineering factors which do not necessarily apply to the design of a fixed, or point-to-point system. The design procedure is a combination of theoretical and empirical methods, which when taken with measured data, produce a system design meeting the required specifications. This paper will treat that portion of the system design pertaining to radio frequency propagation and system coverage. It stresses a realistic measurement program which will provide coverage data in support of the system design.     

An analytical approach to the coverage of a hemisphere by n planar phased arrays

The coverage of a hemisphere byNplanar phased arrays arranged in pyramids or pyramidal frustra is discussed. Transformations between the spherical coordinates of individual arrays and of the hemisphere of coverage are derived. These results are then used to determine the minimum value of the maximum scan angle required of each array and the positioning of the arrays. Numerical results are given. These transformations are also used to minimize the number of elements needed in a given array aperture. This is shown for an example with both equilateral triangular and rectangular element spacing. It is further demonstrated how the use of an isosceles triangular element spacing affords additional reduction of the number of elements needed.     

On the analytical computation of the interference statistics withapplications to the performance evaluation of mobile radio systems

We provide a general analytical framework for the computation of the interference statistics in mobile radio cellular systems. This approach, which takes into account log-normal shadowing, distance path loss, best cell site selection and power control based on signal strength, applies to various cellular environments, including narrowband systems (e.g., IS-54 and Group Special Mobiles GSM) and code-division multiple-access (CDMA) systems. Some examples of application are provided     

An approach to agent-based service composition and its application to mobile business processes

This paper describes an architecture model for multiagent systems that was developed in the European project LEAP (Lightweight Extensible Agent Platform). Its main feature is a set of generic services that are implemented independently of the agents and can be installed into the agents by the application developer in a flexible way. Moreover, two applications using this architecture model are described that were also developed within the LEAP project. The application domain is the support of mobile, virtual teams for the German automobile club ADAC and for British Telecommunications.     

Benefits and feasibility of the partial loading approach incellular mobile radio systems

This paper analyzes the feasibility and potential benefits of following a novel design strategy for cellular systems known as partial loading. This strategy seeks low channel occupancy per cell at the capacity limit, as opposed to the high channel occupancy per cell of more conventional design strategies. By doing so, a considerable flexibility for the radio resource management is obtained, which can be exploited both to increase system capacity and to ease the accommodation of highly fluctuating traffic. A comprehensive system capacity analysis has been performed, based on an analytical model, and it is shown that the introduction of flexibility through partial loading has a capacity cost associated with it. However, it is shown that when that flexibility is properly exploited by adaptive radio link control techniques, such as link adaptation, frequency hopping, or call admission control policies, that cost is more than compensated for, making the partial loading approach a very attractive strategy for the evolution of current TDMA systems and the design of future ones     

Outage statistics in CDMA mobile radio systems

The statistics of the outage events in the reverse link of a direct sequence code-division multiple access (DS/CDMA) wireless system are investigated taking into account the effects of correlated Rician fading. The outage probability and the average fade duration are derived by assuming a constant multipath intensity profile, which includes a direct-path component in the first path. Simulations have been carried out which validate the analytical results     

Doppler spread estimation in mobile radio systems

In this letter, Doppler spread estimation in digital mobile radio systems is described. A maximum-likelihood approach is derived, and used to develop suboptimal approaches with lower complexity. The proposed algorithms rely on periodic channel estimation and can be used in both TDMA and CDMA systems     

Vehicle location in cellular mobile radio systems

A tutorial discussion of vehicle location as used to control cellular mobile radio systems is presented. Early concepts and misconceptions concerning vehicle location are described, and the relation between location "accuracy" and system performance optimization is discussed. Measurement parameters commonly used for vehicle location are described, and considerations relating to the algorithm used in the location process are presented.     

Capacity of cellular mobile radio systems

A lower bound to the Shannon capacity of the uplink channel of a cellular system, with perfect channel state information (CSI) at the receiver, is evaluated against the reuse distance and the level of shadowing affecting the interfering signals. Capacity is normalised to the covered area and expressed in bit/s/Hz/unit area     

Elements of cellular mobile radio systems

A major concern in a cellular mobile radio system is the co-channel interference. Therefore, the reduction of co-channel interference becomes a main thrust for the system design engineers. We use the co-channel interference reduction factor as a design criterion and predict the signal-to-interference (S/I) ratios in different system configurations. The handoff mechanism and algorithmic considerations, the traffic capacity and procedure for splitting cells, and the near-end-to-far-end ratio interference and reduction are the elements described.     

Outage possibilities in mobile radio systems suffering cochannelinterference

Mobile radio systems are usually designed on the basis of providing adequate reception quality to a specified area. The outage probability equations are used to determine the quality of radio reception when that quality is limited by a minimum required signal level, interference from a cochannel transmitter, and variability in the received signal levels. Considering Rayleigh fading and lognormal shadowing as joint causes of signal variation, average outage probability expressions are derived for mobile radio systems of a uniform nature. These expressions are used to investigate the influence of various system and propagation characteristics on reception quality     

Propagation and coverage prediction for cellular radio systems

The development of a computerized UHF signal propagation and coverage prediction system for Singapore is described. This system consists of a terrain database, a propagation prediction model, and a subsystem to plot coverage patterns. The predicted results were verified by field strength measurements. The comparison showed that the errors of the prediction for two UHF bands have a standard deviation of less than 10 dB     

Security services for protecting radio mobile systems

The development of radio networks has brought the problem of security specifically related to mobility of terminals sharply into focus, and has created the need for radio network operators to implement new security functionalities. The security level of the analog radio mobile systems (the so-called “first generation ” systems was very low, and these systems were often exposed to massive fraud. The development of digital radio mobile systems (the so-called “second generation” systems: GSM, DECT,. allowed the systematic introduction of cryptology based protection mechanisms. Hence, for gsm networks for instance, the main fraud and confidentiality problems were taken into account at the design stage and a security architecture was implemented to provide security services to users and network operators. The third generation mobile telecommunication systems belonging to the imt- 2000 family (which are still under specification within standardisation bodies in particular within the 3gpp worldwide third generation partnership project) will, in the forthcoming years, provide a wide variety of services on a single terminal in a multi-environment (domestic, public, business), multi-operator, and multi-service provider context. Security will be based on second generation systems security functions that have proved to be needed and reliable, and shall be adapted and improved to resolve security threats underlying to new services supplied by third generation radio systems. This document presents examples of security solutions currently implemented for protecting second generation radio mobile systems against frauds and attacks and gives an overview of potential solutions for protecting future third generation radio mobile telecommunication systems.