الفهرس 
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Abstract
Demands on broadband data service are increasing dramatically each year.
Following terrestrial trends, satellite communication systems have moved from the
traditional TV broadcasting to provide interactive broadband services even to urban users.
The cellular and land-line networks are mainly designed to deliver broadband services to
metropolitan and large urban centres. However, High Throughput Satellite (HTS)
technology has the advantage of accepting these demands over wide geographically
regions, including areas without backbone connectivity (maritime, aeronautic, rural, etc..)
and high densely populated areas that has an existing communication infrastructure.
Consequently, high throughput satellite is an alternative competitive solution. However,
to stay competitive with economical terrestrial solutions in urban areas, it is necessary to
reduce the cost per transmitted bit by increasing the capacity of the satellite systems.
Geostationary HTS is an evolution of the conventional spacecraft, and it is a satellite
system that uses a large number of geographically spot beams distributed over a specified
service area. Present HTS technology employs the frequency reuse technique to the spot
beam approach to support high overall throughput. The current design can increase the
satellite capacity to be in hundreds of gigabits per second (Gbps) compared to a few Gbps
for Fixed Satellite Services (FSS) satellites.
This dissertation takes the challenge of investigating the interference model for a
new methodology called Coded beam HTS (CB-HTS) that based on applying an
Orthogonal- Code Division Multiple Access (CDMA) technique on the multibeam HTS
system, this new approach increases the system capacity and efficiently utilize the overall
satellite bandwidth for each spot beam. while the present technology limits the spot beam
bandwidth to a portion of the available satellite bandwidth, depending on the frequency reuse factor. The CB-HTS was introduced and analysed in previous work with the
assumptions of no other beams interferences and ideal CDMA codes are used.
The contribution of this thesis can be summarised in three points. First, it proposes
an interference model for coded beam high throughput satellite ( CB-HTS) using Digital
Video Broadcasting standards - S2 (DVB-S2), MODCODE for a multibeam satellite
communication system. As a result, for CB-HTS, inter-beam interference, intra-beam
interference, and other beam interference is characterized.
Second, Signal to interference ratio (S/I) and the other beam interference factor both
are described and calculated for different positions inside the beam especially at the border,
which is considered the most critical position regards the interference issue. Also, the total
user -downlink system capacity is calculated for the CB-HTS using a bandwidth of 1.05
GHz in Ka-band, the BATS system of with 302 beams over Europe, to provide a visual
representation of the throughput and capacity. Third, the performance for the CB-HTS and
the conventional HTS system are compared with (multi-FDMA/TDMA). In addition to a
comparison between CB-HTS system with neglecting the inter-beam interference and with considering it .