Statistical characterization of the interference on the return link of a broadband satellite system (original) (raw)

Interference in Cellular Satellite Systems

Satellite Communications, 2010

Since satellite systems are bandwidth limited, the subdivision of beams into smaller portions allow for frequency reuse to increase capacity. The available bandwidth is shared among these beams as depicted in Figure 1 for reuse factor of n.

Irregular beam sizes and non-uniform bandwidth allocation in HTS multibeam satellite systems

Current HTS multibeam satellite systems assume a uniform offered traffic per beam, but it is foreseen that future traffic demands will be highly uneven over the coverage area. Then imbalances result in some user beams being overprovisioned whilst others are under provisioned resulting in lower satisfaction for user traffic demands. One of the major challenges in designing a future broadband satellite system is how to increase the operators revenue and cope with the uneven traffic demands simultaneously. In the literature, it has been proposed to overcome these imbalances either by applying non-uniform bandwidth distribution (in the frequency domain or beam hopping - in the time domain) or by engineering the beam sizes such as to balance the traffic demands over the beams. In this paper, we propose a joint optimisation of non-uniform bandwidth allocation and non-uniform beam sizes to better match the traffic demands, increase the total useful capacity and utilise the limited space resources more efficiently. The proposed method is applied for a hypothetical traffic scenario over Europe, where a maximum number of 200 user beams is assumed. Only the forward direction is studied herein. The DVB-S2 air interface is considered. A transparent payload is considered, where the user links operate in Ka-band. The results of the forward link are presented and compared with a uniform design and a case with only non-uniform bandwidth allocation. The improvements due the joint optimisation are presented, and the implications to the system design are discussed.

The Single Frequency Satellite Network Concept: Multiple Beams for Unified Coverage

GLOBECOM 2009 - 2009 IEEE Global Telecommunications Conference, 2009

This paper investigates the concept of Single Frequency Satellite Networks (SFSNs), whereby multiple satellite beams that have no form of mutual phase coherence are unified through baseband signal processing to achieve uniform coverage across wide areas. We present a realistic application scenario and its link budget analysis, which allows to highlight the advantages with respect to a classic single beam approach. Our technique is based on the use of orthogonal frequency division multiplexing and on the creation of synthetic multipath at the gateway, realizing a form of delay diversity. The synthetic power delay profile is beam specific, and it is the key instrument that allows to avoid destructive interference amongst the signals transmitted from the multiple beams. The main benefit is that homogeneous coverage is guaranteed with a generic multi-beam antenna, that can be easily reconfigured according to traffic and service needs.

Interference Coordination for the Return Link of a Multibeam Satellite System

Future internet demands are being increased dramatically year by year. Terrestrial systems are unable to satisfy these demands in all geographical areas and thus broadband access by satellite is a key service provision platform. Considering the traffic demands, the raw capacity should approach a Terabit/s by 2020 to meet these demands. The satellite communications network will be a star-based topology, where User Terminals (UT) from multiple beams communicate via central Gateway Earth Stations (GES). The return link from UT to satellite will use DVB-RCS2 Multi-Frequency Time Division Multiple Access (MF-TDMA) transmission scheme in Ka band (30GHz), while the return feeder link from satellite to GES in Q band (40 GHz). Due to generation of large number of narrow user beams, the interference starts becoming a limiting factor in the system’s dimensioning. Herein, interference coordination schemes, borrowed from terrestrial cellular systems, are examined in terms of applicability and C/I performance. In addition, an algorithm for dynamic interference coordination is proposed to schedule the transmissions of the users in time-frequency domain of the return link, aiming to improve the C/I. The performance of these schemes and the proposed algorithm is assessed over a 302 user beams satellite system with practical antenna radiation patterns.

Throughput distribution analysis of return link multi-gateway interference cancellation strategies for multi-beam broadband satellite systems

2012 IEEE Globecom Workshops, 2012

This paper presents the study of the throughput distribution for several interference cancellation and gateway cooperation strategies for the return link of a multi-gateway multibeam broadband satellite system. Different coverage schemes and frequency reuse patterns are considered, taking into account practical system parameters and antenna design. Aim of this work is to provide a tool to ease the seek of design trade-offs, as between spectral efficiency and system complexity. This is addressed showing the distribution of SINR (signal-to-interference plus noise ratio) and the throughput distribution considering different interference cancellation techniques, leveraging on different degrees of cooperation between gateways.

Beam Coverage Comparison of LEO Satellite Systems Based on User Diversification

IEEE Access, 2019

To achieve global network coverage and the need for high-speed communication, the idea of providing Internet access from space has made a strong comeback in recent years. The low earth orbit (LEO) communication satellite constellation is once again on the stage of the world with its unique features and new technology. In order to provide faster and more affordable communication resources, low-orbit satellites need be customized to design satellites. The beam coverage design is essential to the user-customized design. This paper combines the user traffic demand model and the low-orbit satellite beam coverage model to analyze the impact of beam coverage characteristics on the performance of low-orbit satellite systems. The user traffic model bases on the user simulative distribution (uniform, normal) and the user geographic distribution (according to the AIS and ADS-B historical data acquired by STU-2B and STU-2C which are the LEO satellites launched in Sep, 2015, Jiuquan, China). The beam coverage model compares the OneWeb system to the SpaceX system. The beam coverage model takes the variability in performance induced by atmospheric conditions for the user links into account. Follow that this paper proposes a system method to simulate the two satellite system which described by the throughput, delay, access probability. Finally, the sensitivity of beam coverage to user diversification is summarized and discussed.

Optimal packet allocation methods in multi-beam satellite architecture using FTDMA on the Return Link

29th AIAA International Communications Satellite Systems Conference (ICSSC-2011), 2011

This paper introduces new techniques to enhance the construction of frames in a MF-TDMA communication system for a high throughput broadband Satellite system. It is a function of one main parameter: the Carrier-over-Interference (C/I) performance at antenna level taking into account geographical constraints. The satellite architecture uses a multi-beam coverage implementing frequency re-use and spatial separation on a Return Link.

Performance study of multiuser interference mitigation schemes for hybrid broadband multibeam satellite architectures

EURASIP Journal on Wireless Communications and Networking, 2012

As the demand for higher throughput satellites increases, multibeam architectures with smaller beam spots are becoming common place. If the same frequency is strongly reused, the resulting interference when serving simultaneously many users requires some sort of pre or post-cancelation process. This article focuses on precoding and multiuser detection schemes for multibeam satellites, comparing hybrid on-board on-ground beamforming techniques with fully ground-based beamforming. Both techniques rely on the exchange of radiating element signals between the satellite and the corresponding gateway but, in the latter case, the interference mitigation process acts on all the radiating signals instead of the user beams directly, with the corresponding extra degrees of freedom for those cases for which the number of radiating elements is higher than the number of user beams. The analysis carried out in this study has shown that the potential advantage of ground-based beamforming may exceed 20% of the total throughput.

Cognitive spectrum utilization in Ka band multibeam satellite communications

IEEE Communications Magazine, 2015

Multibeam satellite networks in Ka band have been designed to accommodate the increasing traffic demands of the coming years. However, these systems are spectrum limited due to the current spectrum allocation policies. This paper investigates the potentials of applying cognitive radio techniques in satellite communications in order to increase the spectrum opportunities for future generation of satellite networks without interfering operation of incumbent services. These extra spectrum opportunities can potentially amount to 2.4 GHz of bandwidth in downlink, and to 2 GHz of bandwidth in uplink for high density fixed satellite services (HDFSS).