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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 . |