625 research outputs found
Cooperative Retransmissions Through Collisions
Interference in wireless networks is one of the key capacity-limiting
factors. Recently developed interference-embracing techniques show promising
performance on turning collisions into useful transmissions. However, the
interference-embracing techniques are hard to apply in practical applications
due to their strict requirements. In this paper, we consider utilising the
interference-embracing techniques in a common scenario of two interfering
sender-receiver pairs. By employing opportunistic listening and analog network
coding (ANC), we show that compared to traditional ARQ retransmission, a higher
retransmission throughput can be achieved by allowing two interfering senders
to cooperatively retransmit selected lost packets at the same time. This
simultaneous retransmission is facilitated by a simple handshaking procedure
without introducing additional overhead. Simulation results demonstrate the
superior performance of the proposed cooperative retransmission.Comment: IEEE ICC 2011, Kyoto, Japan. 5 pages, 5 figures, 2 tables. Analog
Network Coding, Retransmission, Access Point, WLAN, interference, collision,
capacity, packet los
The future of camera networks: staying smart in a chaotic world
Camera networks become smart when they can interpret video data on board, in order to carry out tasks as a collective, such as target tracking and (re-)identi cation of objects of interest. Unlike today’s deployments, which are mainly restricted to lab settings and highly controlled high-value applications, future smart camera networks will be messy and unpredictable. They will operate on a vast scale, drawing on mobile resources connected in networks structured in complex and changing ways. They will comprise heterogeneous and decentralised aggregations of visual sensors, which will come together in temporary alliances, in unforeseen and rapidly unfolding scenarios. The potential to include and harness citizen-contributed mobile streaming, body-worn video, and robot- mounted cameras, alongside more traditional xed or PTZ cameras, and supported by other non-visual sensors, leads to a number of di cult and important challenges. In this position paper, we discuss a variety of potential uses for such complex smart camera networks, and some of the challenges that arise when staying smart in the presence of such complexity. We present a general discussion on the challenges of heterogeneity, coordination, self-recon gurability, mobility, and collaboration in camera networks
Satellite-Based Communications Security: A Survey of Threats, Solutions, and Research Challenges
Satellite-based Communication systems are gaining renewed momentum in
Industry and Academia, thanks to innovative services introduced by leading tech
companies and the promising impact they can deliver towards the global
connectivity objective tackled by early 6G initiatives. On the one hand, the
emergence of new manufacturing processes and radio technologies promises to
reduce service costs while guaranteeing outstanding communication latency,
available bandwidth, flexibility, and coverage range. On the other hand,
cybersecurity techniques and solutions applied in SATCOM links should be
updated to reflect the substantial advancements in attacker capabilities
characterizing the last two decades. However, business urgency and
opportunities are leading operators towards challenging system trade-offs,
resulting in an increased attack surface and a general relaxation of the
available security services. In this paper, we tackle the cited problems and
present a comprehensive survey on the link-layer security threats, solutions,
and challenges faced when deploying and operating SATCOM systems.Specifically,
we classify the literature on security for SATCOM systems into two main
branches, i.e., physical-layer security and cryptography schemes.Then, we
further identify specific research domains for each of the identified branches,
focusing on dedicated security issues, including, e.g., physical-layer
confidentiality, anti-jamming schemes, anti-spoofing strategies, and
quantum-based key distribution schemes. For each of the above domains, we
highlight the most essential techniques, peculiarities, advantages,
disadvantages, lessons learned, and future directions.Finally, we also identify
emerging research topics whose additional investigation by Academia and
Industry could further attract researchers and investors, ultimately unleashing
the full potential behind ubiquitous satellite communications.Comment: 72 page
- …