The Effect of Human Presence on Signal Power
Received at a TETRA Handled Device
Abstract - The attenuation of the radio signal in the near field of a
tetra handled device due the the presence of human body is measured.
By including a confidence margin for the mean and the standard
deviation of the measurements we find in open area 8.4dB attenuation
when the handled device is at talking position close lo the head and
19.3dB when it is placed at the belt. In urban environment the
corresponding values ore 11.2 and 9.2d dB respectively. Detailed
measurements are presented and discussed.
Radio Channel Description and Quality of Service
for TETRA Direct Mode Operation in Forest Environments
Abstract- This paper describes radio channel and BER investigations
performed in various scenarios typical to the TETRA Direct Mode Operation
(DMO), in a forest area. The data from radio channel sounding measurements
was analyzed in terms of average fade duration and envelop CDF.
The same data was used to evaluate the unprotected BER on a TETRA
communication link. The BER level distribution was compared to the the
distribution obtained when simulating a pedestrian speed TETRA DMO
radio channel. The dynamics of the mobiles can have a strong influence
on the radio link quality. As a general tendency, higher practical BER values
can be expected as compared to the simulations when using the simple
TETRA radio channel model.
An NAI resolution mechanism for GPRS and TETRA PMR networks
INTRODUCTION
Dialup users of data networks that use the Point-Point Protocol
(PPP) make use of a Network Address Identifier (NAI) [4] for
user identification. NAI is also being used for roaming and
tunneling service in data networks. On the other hand, cellular
networks make use of an alternative user identification format
which is usually the International Mobile Subscriber Identity
(IMSI) or the Mobile Identification Number (MIN). Similarly,
Terrestrial Trunked Radio (TETRA) based Professional
Mobile Radio (PMR) networks make use of the Individual
TETRA Subscriber Identity (ITSI) for user identification.
With the impending integration of cellular RMR networks and
data networks, it is desirable to have a one-one mapping
between IMSI/MIN/ITSI and NAI. An operational procedure
is needed whereby such a mapping occurs within the network
and is transparent to the user. The MobileIP working group
‘within the IETF is currently investigating such a mapping [3]
for cellular networks. However, no mechanisms have been
described for GPRS or TETRA networks. In this report, we
outline a mechanism for such a mapping and the associated
operational procedures when the cellular network is a General
Packet Radio Service (GPRS) [l] network and also when the
access network is a TETRA PMR network.
Link adaptation to improve coverage in
TETRA PMR system
An investigation is presented into the application of link
adaptation, the alteration of channel coding depending on the
channel quality, to speech transmission in terrestrial trunked radio
(TETRA) systems. A comparison is made of the performance of
the technique to that obtained under quasi-synchronous operation
which is also proposed for TETRA range extension.
DYNAMIC BEARER SELECTIONS SCHEMES IN AN ADAPTIVE TETRA
RESOURCE MANAGER AND THEIR INFLUENCE ON QOS
Abstract - This paper investigates the use of link adaptation
techniques for the TETRA air interface. For this purpose, a
radio resource management scheme is presented along with
the notion of quality of service (QoS) contract. A QoS
contract is the means for specifying the expected network
performance and optionally enables the user
applicatiodservice to specify a degree of degradation
tolerance over the wireless link. The paper presents
simulation results showing the effect of various parameters
on what can be delivered by the TETRA system.
Furthermore, a service adaptation scheme for multimedia
applications is presented for complementing link adaptation.
Simulation Analysis of the Air Interface
Protocol for TETRA system
Abstract: In this paper, the developing
prospect of the digital trunking system is
introduced firstly. On the basis of the computer
simulation for the TETRA air interface protocol,
the collision ratio and the mean number of
success access in the MCCH with the random
access method of the ALOHA protocol is
analyzed and proved, as well as the relationship
between call loss, channel utilization and the
system traffic. And then the capacity for the
users of the standard mode of TETRA system is
calculated
SPACE DIVERSITY RECEPTION TECHNIQUES FOR THE TETRA PMR
SYSTEM
In mobile radio systems the effects of fading can be
counteracted by the use of diversity techniques either at
the base station or the mobile. Since reducing fading,
diversity schemes contribute to the reduction of the bit
error rate that degrades the performance of any
modulation scheme. This paper attempts to determine
the performance of a typical TETRA system, without
diversity for a variety of operating conditions and
environments. This will provide a benchmark for
assessing any benefits that diversity techniques will
bring. Also it aims to find the limits of performance that
can be achieved by using a two-branch
Sorne shel.t--range radio devices are suffering interference
from the Tetra radio system. Nick Long reviews the origins of
this problem and the lessons for radio designers
Quasi-Synchronous Digital Trunked TETRA Performance
Abstract— In some private mobile radio/public access mobile
radio (PMR/PAMR) applications, there is a stringent need
for high-coverage locations probabilities. A spectrally efficient
approach in this case is the use of several radio transmitters
operating in simulcast mode. There have been several analog
mobile radio systems working in this way up to now, but less
is known about the performance of digital trunked radio systems
operating in simulcast mode. In this paper, predicted digital
Trans-European Trunk RAdio (TETRA) system performance
results operating in quasi-synchronous mode are presented. These
results were obtained by simulation of such a system under a wide
range of operational conditions. A comparison is also presented
with the European analog standard MPT 1327 currently in operation.
It has been concluded that quasi-synchronous techniques
well known in analog PMR/PAMR can also be successfully used
in digital PMR/PAMR applications.
PERFORMANCE IMPROVEMENT BY USING DIFFERENT
TRANSMISSION TECHNIQUES FOR THE DIGITAL MOBILE RADIO
SYSTEM TETRA
Abstract.-This paper deals with different transmission
techniques in order to improve the TETRA system
performances. First of all, it describes briefly what is
TETRA and which are the propagation models standardised.
After that it will be explained what type of equalizers and
diversity systems have been evaluated. Finally, results of
simulations will be shown and analysed as well as some
conclusions.
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