Application
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Digital Video Broadcasting to Handhelds (DVB-H) allows the provision of
multimedia services to the mobile user (Mobile TV) in a cost-effective
way by the
interworking of broadcasting transmitters with cellular 2G
and 3G user terminals.
AWE Communications provides a planning tool
for DVB-H networks considering the OFDM air interface and the SFN
deployment (incl. the guard interval for possible interferences
introduced by
neighboring transmitters).
The DVB-H radio network planning tool allows the investigation of the
network performance in terms of coverage, SNIR and system margin for
different network configurations incl. gap-fillers within
various environments (rural,
urban,
and indoor).
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Structure
of the DVB-H RNP tool. Click to enlarge.
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Propagation
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Based on the accurate prediction of the radio channel in terms of
path loss delay profiles by
using deterministic ray-optical
wave propagation models the defined DVB-H network is evaluated.
The
calculation of the different path loss delay profiles forms the basis
for the DVB-H system simulation.
For the wave
propagation analysis basically two
different approaches are possible, depending on the network
architecture and the environment. The radio coverage is computed with
the rural/suburban and
urban
wave propagation models
included in the ProMan
tool.
As an example for
both scenarios the following figures describe
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Prediction
of received power
based
on clutter/topo data
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Prediction
of received power
in
urban scenario based on 3D vector data
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Network
Planning
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The DVB-H system
simulator includes a detailed modelling of the DVB-H architecture
(transmitter and user terminal segment). In the
simulator the different parameters influencing the link budget are
considered and the OFDM air interface
is modeled in a detailed manner (with different parameters like guard
interval). By taking into
account the predicted path loss delay profiles of the corresponding
links, different performance measures are
calculated (for different reception conditions portable/mobile).
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Features of network
planning module:
- Transmission in UHF band (or S band for DVB-SH)
- Different transmission modes (2K, 4K, 8K)
trading-off mobility (robustness against Doppler) and SFN size
- Consideration of OFDM air inferface (long
symbol duration with high number of sub-carriers)
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Consideration
of link budget parameters for each contribution (adaptation of power
and delay)
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Superposition
of signals from different transmitters according to their delay
- Consideration of guard interval to avoid
inter-symbol interference
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Define
OFDM receiver according to given parameters (weighting functions for
signal/interference power)
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Evaluation
of C/N and SNIR ratios for different receiver types (portable/mobile)
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Simulated
SNIR coverage
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Databases
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The propagation models in WinProp work with many different types of
databases depending on the scenario which is analyzed (e.g. topography, clutter or building data). Further
information concerning the databases can be found on the database page.
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DVB-H
Radio Network Deployment
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For the network deployment basically two
different approaches are possible. The radio planning tool of AWE
Communications is designed for the
planning of both network types:
- Broadcast Network Approach (DVB-H)
- Usage
of high towers
- Addition of local gap-fillers
- in UHF band
High power
transmitters as well as
local gap-fillers (e.g. for urban & indoor coverage) can be
considered in the DVB-H mode
(see figure). The number of
gap-fillers (depending on their configuration) can be determined in
order
to achieve coverage over an urban area. But also the number of high
power transmitters on nation-wide scale.
In the cellular approach the satellite coverage is extended with
terrestrial repeaters according to DVB-SH
(see
figure), the planning tool must consider not only satellites or terrestrial transmitters. It must
work with both, satellites and
terrestrial transmitters. Especially the interference between satellite
and terrestrial network makes it complicated to plan the broadcasting
network.
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