1,402 research outputs found
On the Interplay Between Edge Caching and HARQ in Fog-RAN
In a Fog Radio Access Network (Fog-RAN), edge caching is combined with
cloud-aided transmission in order to compensate for the limited hit probability
of the caches at the base stations (BSs). Unlike the typical wired scenarios
studied in the networking literature in which entire files are typically
cached, recent research has suggested that fractional caching at the BSs of a
wireless system can be beneficial. This paper investigates the benefits of
fractional caching in a scenario with a cloud processor connected via a
wireless fronthaul link to a BS, which serves a number of mobile users on a
wireless downlink channel using orthogonal spectral resources. The fronthaul
and downlink channels occupy orthogonal frequency bands. The end-to-end
delivery latency for given requests of the users depends on the HARQ processes
run on the two links to counteract fading-induced outages. An analytical
framework based on theory of Markov chains with rewards is provided that
enables the optimization of fractional edge caching at the BSs. Numerical
results demonstrate meaningful advantages for fractional caching due to the
interplay between caching and HARQ transmission. The gains are observed in the
typical case in which the performance is limited by the wireless downlink
channel and the file popularity distribution is not too skewed
Backscatter from the Data Plane --- Threats to Stability and Security in Information-Centric Networking
Information-centric networking proposals attract much attention in the
ongoing search for a future communication paradigm of the Internet. Replacing
the host-to-host connectivity by a data-oriented publish/subscribe service
eases content distribution and authentication by concept, while eliminating
threats from unwanted traffic at an end host as are common in today's Internet.
However, current approaches to content routing heavily rely on data-driven
protocol events and thereby introduce a strong coupling of the control to the
data plane in the underlying routing infrastructure. In this paper, threats to
the stability and security of the content distribution system are analyzed in
theory and practical experiments. We derive relations between state resources
and the performance of routers and demonstrate how this coupling can be misused
in practice. We discuss new attack vectors present in its current state of
development, as well as possibilities and limitations to mitigate them.Comment: 15 page
Coded Slotted ALOHA: A Graph-Based Method for Uncoordinated Multiple Access
In this paper, a random access scheme is introduced which relies on the
combination of packet erasure correcting codes and successive interference
cancellation (SIC). The scheme is named coded slotted ALOHA. A bipartite graph
representation of the SIC process, resembling iterative decoding of generalized
low-density parity-check codes over the erasure channel, is exploited to
optimize the selection probabilities of the component erasure correcting codes
via density evolution analysis. The capacity (in packets per slot) of the
scheme is then analyzed in the context of the collision channel without
feedback. Moreover, a capacity bound is developed and component code
distributions tightly approaching the bound are derived.Comment: The final version to appear in IEEE Trans. Inf. Theory. 18 pages, 10
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