Joint Precoding and On-Board Beamforming for Multiple gateway Multibeam Satellite Systems

in IEEE Journal on Selected topic in Communication (in press)

This paper aims to design joint precoding and onboard beamforming of a multiple gateway multibeam satellite system, either in a hybrid space-ground mode, or in a totally on-board one. In such an ... [more ▼]

This paper aims to design joint precoding and onboard beamforming of a multiple gateway multibeam satellite system, either in a hybrid space-ground mode, or in a totally on-board one. In such an architecture, with employing high throughput full frequency reuse pattern over both user and feeder links, each gateway serves a cluster of adjacent beams such that the adjacent clusters are served through a set of gateways that are located at different geographical areas. However, such a system brings in two challenges to overcome. First, the interference in both user and feeder links is the bottleneck of the whole system and applying interference mitigation techniques becomes necessary. Second, as the data demand increases, the ground and space segments should employ extensive bandwidth resources in the feeder link accordingly. This entails embedding an extra number of gateways aiming to support a fair balance between the increasing demand and the corresponding required feeder link resources. To solve these problems, this study investigates the impact of employing a joint multiple gateway architecture and on-board beamforming scheme. It is shown that by properly designing the on-board beamforming scheme, the number of gateways can be kept affordable even if the data demand increases. Moreover, Zero Forcing (ZF) precoding techniques are considered to cope with the interference in both user and feeder links which embed in the following premises: (i) each gateway constructs a part of block ZF precoding matrix, (ii) the satellite and gateways perform the precoding scheme, and (iii) a joint design of ZF precoding and on-board beamforming at the payload of the satellite so that no signal processing scheme is conceived at the gateways. The provided simulation results depict the performance gain obtained by our proposed schemes. [less ▲]

Deploying Dynamic On-Board Signal Processing Schemes for Multibeam Satellite Systems

in Deploying Dynamic On-Board Signal Processing Schemes for Multibeam Satellite Systems (2019)

This paper designs dynamic on-board signal processing schemes in a multiple gateway multibeam satellite system where full frequency reuse pattern is considered among the beams and feeds. In particular, we ... [more ▼]

This paper designs dynamic on-board signal processing schemes in a multiple gateway multibeam satellite system where full frequency reuse pattern is considered among the beams and feeds. In particular, we deploy on-board Joint Precoding, Feed selection and Signal switching mechanism (JPFS) so that the following advantages are realized, I) No need of Channel State Information (CSI) exchange among the gateways and satellite, since the performance of precoding is highly sensitive to the quality of CSI, II) In case one gateway fails, rerouting signals through other gateways can be applied without any extra signal processing, III) Properly selecting on-board feed/s to serve each user which generates maximum gain toward corresponding user, IV) Flexibly switching the signals received from the gateways to requested users where each user can dynamically request traffic from any gateway, and V) Multiple user with multiple traffic streams can be dynamically served at each beam. However, deploying such JPFS architecture imposes high complexity to the satellite payload. To tackle this issue, this study aims at deploying JPFS that can provide affordable complexity at the payload. In addition, while increasing the data demand imposes extensive bandwidth resources requirement in the feeder link, the proposed JPFS design works efficiently with available feeder link resources even if the data demand increases. The proposed design is evaluated with a close-to-real beam pattern and the latest broadband communication standard for satellite communications. [less ▲]

On-Board Precoding in a Multiple Gateway Multibeam Satellite System

in Proceedings of IEEE VTC Fall 2018 (2018)

This paper present On-Board Precoding (OBP) for a multiple gateway multibeam satellite system where full frequency reuse pattern is employed at both user and feeder links. By reducing the Channel State ... [more ▼]

This paper present On-Board Precoding (OBP) for a multiple gateway multibeam satellite system where full frequency reuse pattern is employed at both user and feeder links. By reducing the Channel State Information (CSI) roundtrip delay to half, OBP offers significant benefits in the emerging multiple gateway scenario in terms of lower gateways coordination. However, two critical issues need to be addressed: (a) interference in both user and feeder links is the bottleneck of the whole system and employing interference mitigation techniques is essential, (b) clear push towards non-adaptive (fixed) payload implementation, leading to low computationally complex satellite architectures. In order to fulfill requirements (a) and (b), this paper studies the impact of employing a fixed OBP technique at the payload which is sufficiently robust to the variations in both user and feeder link channels. In addition to (a) and (b), the provided simulation results depict the performance gain obtained by our proposed OBP with respect to the conventional interference mitigation techniques in multiple gateway multibeam systems. [less ▲]

Precoder Design for Multibeam Mobile Satellite Systems

in Proceedings of IEEE Asilomar Conference on Signals, Systems and Computers (2018)