A Diversity Reception Scheme for TETRA Multi-carrier System
Abstract—A maximal ratio combination(MRC) diversity
reception scheme for TETRA multi-carrier system is present.
TETRA enhance data service(TEDS) standard adopts Filter-
Bank Multi-Carrier Modulation(FBMCM) and QAM schemes
in order to improve the transmission rate. Space diversity is
considered as an efficient way to reduce the impact of fading.
TEDS specifies its own preamble for timing synchronization,
frequency offset estimation and channel equalizer. In this
paper, a MRC diversity reception scheme which makes use of
the special preamble is proposed. Simulation result shows that
the proposed schemes exhibit good performances in the
channel model defined in TETRA.
Traffic Performance Evaluation of Data Links in TETRA and TETRAPOL
Abstract
TETRA and TETRAPOL are competitors in the market of Professional Mobile Radio (PMR). In a previous
study [1] we compared the trunked mobile radio systems TETRA V + D and TETRAPOL by evaluating random
access performance. Here we present a comparison of the TETRA and TETRAPOL error correction schemes
involved to secure LLC data links. The traffic performance of both systems was compared for ETSI scenario
8 [2]. Realistic models for the effects of propagation circumstances and co-channel interference are taken into
account. The results of the traffic performance measurements exhibit differences in connection set-up times
and transmission delays for data links in TETRA and TETRAPOL systems in favour of the TETRA system
and reveal a strong dependency on random access delays
Research on the Assignment Mechanism of TETRA Event Labels
Abstract— An event label is temporary shortened form of address
defined in TETRA specifications, and it can save more bits in the
air interface, compared to a Short Subscriber Identity (SSI).
Because there is quite limited literature related to event labels,
event labels are not supported in most TETRA systems yet. A
novel assignment mechanism, including the data structure and a
detailed SDL state chart, is presented in this paper. This paper
introduces the basic concept of event labels and evaluates the
impact of event labels in four most common used TETRA
services: voice call setup, short data service, group
attachment/detachment and packet data service. Simulation
results show event labels will improve the performance of short
data services, group attachment/ detachment and packet data
services.
Abstract—In finite TETRA system, base stations can be formed
in wireless muti-hop fashion. This paper investigates two
fundamental characteristics of a wireless base station network:
its connectivity and its maximum coverage area. First, by
analyzing the isolated node, we obtain the relationships
between the number of nodes, transmission range and network
connectedness. Based on the results of connectivity, we
calculate the minimum number of frequencies of each base
station should maintain. Furthermore, we propose a theorem
to determine the topology of a connected network achieving the
maximum coverage area.
Characterization of Impedance Variations in
antennas for TETRA terminals
Abstract—Antenna input impedance is usually considered as
a non-dynamical magnitude, which remains constant during the
transmission or reception process. The main advantage is that
it allows to simplify matching circuit design. However, in an
actual situation, the impedance value is a dynamic quantity
that can be very different compared to the static value. In this
paper, we propose a histogram based method in order to identify
the impedance variation of TETRA antennas. The statistical
approach is carried out in the matching domain rather than in the
impedance domain, because in this way the random vector has
a compact support. The method is applied to model a practical
situation where the terminal position changes from the user’s
pocket to the head, obtaining a bimodal distribution which cannot
be identified directly by means of parametric methods. We prove
experimentally that the dynamical values are different from the
results obtained in an anechoic chamber, and it is required to
perform a cluster analysis or a non parametric method to identify
accuratelly the probability density function which characterizes
the antenna impedance.
Performance Evaluation of Phase Modulation
Schemes for TETRA Application
Abstract—Phase Modulation schemes have been extensively
used in mobile systems. TETRA -1 supports π/4-DQPSK,
where as TEDS supports π/8-D8PSK along with QAM
schemes in order to achieve higher data rate. In this paper
the performance of phase modulation schemes over TETRA
propagation models TU-5, TU-50 and HT-200 is presented.
Implementation of higher order modulation schemes help
understanding the performance of Phase modulations
schemes for broadband TETRA. Implementation efficiency
is analysed in terms of Message Error Rate (MER) against
Es/No over SCH\F channel for downlink bursts in the
400MHz TETRA frequency bands.
Voice End-to-End Encrypted for TETRA
Radiocommunication System
Abstract— The standard TETRA (Terrestrial Trunked Radio)
system addresses a number of security issues, one being the
cryptographic protection of signaling data and user data on the
highly exposed air interface. However, user data travels
unencrypted within the network infrastructure. This precludes
the use of TETRA systems by those users who regard their
transmissions as particularly sensitive, and whose Security Policy
requires all such data to be appropriately encrypted whilst in
transit between the end terminals in any system. End-to-end
encryption addresses these concerns by encrypting data within
the transmitting terminal, and only decrypting it within the
receiving terminal. The plain data is never exposed within the
infrastructure; in fact the infrastructure contains no mechanism
to recover it should it wish to do so.
A Real-Time Intelligent Wireless
Mobile Station Location Estimator with
Application to TETRA Network
Abstract—Mobile location estimation has received considerable interest over the past few years due to its great potential in different
applications such as logistics, patrol, and fleet management. Many mobile location estimation techniques had been proposed to
improve the accuracy of location estimation. Location estimation based on artificial intelligence techniques is a recent alternative
approach. In this paper, Adaptive Neuro-Fuzzy Inference system (ANFIS) is used as a robust location estimator to locate the mobile
station (MS) using the MS geo-fencing area data within 9 km from a serving base station. Extensive evaluations and comparisons have
been performed, and a set of statistical parameters has been obtained. From the comparison of the proposed ANFIS estimator with the
neural-network-based estimators, it is found that ANFIS estimator is faster and more robust. Its Average Computation Time (ACT) is
0.076 sec. While the ACT for Multilayer Perceptron (MLP) and Radial-Based Function (RBF) neural networks is 0.88 and 1.7,
respectively. Whereas on comparing ANFIS with other techniques, it is found that in ANFIS estimator, 67 percent of the estimated
location errors do not exceed 149 m, while these for the statistical, multiple linear regression, and geometric are 170, 280, and 2,346 m,
respectively. Thus, the results clearly reveal that the proposed ANFIS estimator outperforms all other techniques.
General System Architecture of TETRA Network for Public Safety Services
Abstract – In the ten years since TETRA (Terrestrial Trunked Radio) standard from ETSI (European
Telecommunications Standards Institute) has been available on the worldwide market, it has become the leading
PMR (Private/Professional Mobile Radio) technology of choice especially in networks for public safety. Since it
was first standardized the system evolved in various directions, both in application and technology point of view.
This paper gives an overview of general TETRA system arhitectures available on the market today. It also gives
an in depth analisys of a specific IP based TETRA system core elements and their function in the overall
communication process.
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TETRA conference papers
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