Cross-polarisation discrimination-induced interference in dual-polarised high-capacity satellite communication systems

The design of spectrally-efficient, high-throughput satellite (HTS) systems with capacity approaching one terabit per second requires operating at Ka-band frequencies and above, where there are several gigahertz of allocated radio spectrum, using multiple spot beams with dual orthogonal polarisation mode. At these high frequencies, rain attenuation poses a major obstacle to the design of high-availability satellite links which are needed for the realisation of ubiquitous broadband multimedia communication services including high-speed Internet access at rural and remote locations. Furthermore, depolarisation-induced interference in such systems could have a performance-limiting impact if a co-channel cross-polar signal combines with system noise to drive the carrier-to-noise-plus-interference ratio (CNIR) below an acceptable threshold. This paper employs real measurement data to investigate the impact of depolarisation-induced interference on dual-polarised HTS systems for temperate and tropical climatic regions. Scenarios that cause significant system performance degradation are analysed, including the effects of signal frequency, antenna size, and regional rainfall rate. The impact of depolarisation on system performance is quantified by the reductions in the CNIR and link availability of a dual-polarised system when compared with those of a similarly-dimensioned single-polarised system

DECENT: Decentralized and efficient key management to secure communication in dense and dynamic environments

Intelligent Transportation Systems (ITS), one aspect of the Smart City paradigm, aim to improve the efficiency, convenience, and safety of travelers. The integration of (vehicular) communication technologies allows communication between the on-board communication units (OBUs) of vehicles, roadside units (RSUs), and vulnerable road users (VRUs), and contribute to the efficacy of ITS applications. However, these additional sources of information must be reliable and accurate. Security primitives such as confidentiality, integrity, and authenticity are required, but only achievable when supported with a suitable cryptographic key management scheme. This paper presents the design of a decentralized and efficient key management scheme, abbreviated as the DECENT scheme. This scheme provides secure multihop communication in dense and dynamic network environments while functioning in a self-organized manner. Through threshold secret sharing techniques, network nodes act as a distributed trusted third party (TTP) such that a threshold number of nodes can collaborate to execute key management functions. These functions include decentralized node admission and key updating. Novelties include (i) the unique self-healing characteristic, meaning that DECENT is capable of independently recovering from network compromise, and (ii) guidelines for choosing an appropriate security threshold in any deployment scenario which maximizes the level of security while simultaneously guaranteeing that decentralized key management services can be provided

Key management for beyond 5G mobile small cells: a survey

The highly anticipated 5G network is projected to be introduced in 2020. 5G stakeholders are unanimous that densification of mobile networks is the way forward. The densification will be realized by means of small cell technology, and it is capable of providing coverage with a high data capacity. The EU-funded H2020-MSCA project “SECRET” introduced covering the urban landscape with mobile small cells, since these take advantages of the dynamic network topology and optimizes network services in a cost-effective fashion. By taking advantage of the device-to-device communications technology, large amounts of data can be transmitted over multiple hops and, therefore, offload the general network. However, this introduction of mobile small cells presents various security and privacy challenges. Cryptographic security solutions are capable of solving these as long as they are supported by a key management scheme. It is assumed that the network infrastructure and mobile devices from network users are unable to act as a centralized trust anchor since these are vulnerable targets to malicious attacks. Security must, therefore, be guaranteed by means of a key management scheme that decentralizes trust. Therefore, this paper surveys the state-of-the-art key management schemes proposed for similar network architectures (e.g., mobile ad hoc networks and ad hoc device-to-device networks) that decentralize trust. Furthermore, these key management schemes are evaluated for adaptability in a network of mobile small cells

Distributed trusted authority-based key management for beyond 5G network coding-enabled mobile small cells

The 5G cellular network is projected to be introduced in 2020 and takes advantage of the small cell technology to deliver ubiquitous 5G services in an energy efficient manner. The next logical step is the introduction of network coding enabled mobile small cells (NC-MSCs). These are networks of mobile devices which can be set up on-the-fly, based on demand, and cover the urban landscape. Furthermore, they allow network offloading through multi-hop device-to-device (D2D) communication to provide high data rate services. In this paper we introduce DISTANT, a decentralized key management scheme specifically designed to provide security in a network which takes advantage of the benefits of NC-MSCs. In our key management scheme, we distribute the certification authority (CA) functions using threshold secret sharing. Each network node is provided with a share of the master private key such that key management services are available “anywhere, anytime”. Finally, our distributed CA takes advantage of the self-generated certificate paradigm. Certificates can therefore be issued and renewed without the interaction of the distributed CA which minimizes the communication overhead

Public key cryptography without certificates for beyond 5G mobile small cells

The 5G network takes advantage of the small cells technology. The next logical step is to cover the urban landscape with mobile small cells, to optimize network services. However, the introduction of mobile small cells raises various security challenges. Cryptographic solutions are capable of solving these as long as they are supported by appropriate key management schemes. The threshold-tolerant identity-based cryptosystem forms a solid basis for key management schemes for mobile small cells. However, this approach is unable to sustain security over time. Therefore, we introduce two extensions, proactive secret sharing and private key cloaking, to address this challenge

DISTANT: DIStributed trusted Authority-based key managemeNT for beyond 5G wireless mobile small cells

The 5G mobile network is embracing new technologies to keep providing network subscribers with a high Quality of Service (QoS). However, this has become increasingly difficult in the urban landscape as more devices are being connected and each device is requesting increasing amounts of data. Network operators rely on the small cell technology to maintain coverage and service for its subscribers, but this technology is incapable of mitigating the increasing workload on the network infrastructure and preventing the associated network delays. The next logical step is to cover the urban landscape with mobile small cells, since these take advantage of the dynamic network topology and optimizes network services in a cost-effective fashion while taking advantage of the high device density. However, the introduction of mobile small cells raises various security challenges. Cryptographic solutions are capable of solving these as long as they are supported by an appropriate key management scheme. In this article, we propose DISTANT: a DIStributed Trusted Authoritybased key managemeNT scheme. This key management scheme is specifically designed to provide security in a network which takes advantage of the mobile small cell technology. The scheme relies on threshold secret sharing to decentralize trust and utilizes the self-generated certificates paradigm. Through an extensive security analysis and communication overhead evaluation, we conclude that our design provides an improved level of security and has a low communication overhead compared to previous works