4,926 research outputs found
Outer bounds on the error correction capacity region for non-multicast networks
In this paper we study the capacity regions of non-multicast networks that are susceptible to adversarial errors. We derive outer bounds on the error correction capacity region and give a family of single- and two-source two-sink 3-layer networks for which these bounds are tight
The Balanced Unicast and Multicast Capacity Regions of Large Wireless Networks
We consider the question of determining the scaling of the -dimensional
balanced unicast and the -dimensional balanced multicast capacity
regions of a wireless network with nodes placed uniformly at random in a
square region of area and communicating over Gaussian fading channels. We
identify this scaling of both the balanced unicast and multicast capacity
regions in terms of , out of total possible, cuts. These cuts
only depend on the geometry of the locations of the source nodes and their
destination nodes and the traffic demands between them, and thus can be readily
evaluated. Our results are constructive and provide optimal (in the scaling
sense) communication schemes.Comment: 37 pages, 7 figures, to appear in IEEE Transactions on Information
Theor
Physical Layer Service Integration in 5G: Potentials and Challenges
High transmission rate and secure communication have been identified as the
key targets that need to be effectively addressed by fifth generation (5G)
wireless systems. In this context, the concept of physical-layer security
becomes attractive, as it can establish perfect security using only the
characteristics of wireless medium. Nonetheless, to further increase the
spectral efficiency, an emerging concept, termed physical-layer service
integration (PHY-SI), has been recognized as an effective means. Its basic idea
is to combine multiple coexisting services, i.e., multicast/broadcast service
and confidential service, into one integral service for one-time transmission
at the transmitter side. This article first provides a tutorial on typical
PHY-SI models. Furthermore, we propose some state-of-the-art solutions to
improve the overall performance of PHY-SI in certain important communication
scenarios. In particular, we highlight the extension of several concepts
borrowed from conventional single-service communications, such as artificial
noise (AN), eigenmode transmission etc., to the scenario of PHY-SI. These
techniques are shown to be effective in the design of reliable and robust
PHY-SI schemes. Finally, several potential research directions are identified
for future work.Comment: 12 pages, 7 figure
The Three Node Wireless Network: Achievable Rates and Cooperation Strategies
We consider a wireless network composed of three nodes and limited by the
half-duplex and total power constraints. This formulation encompasses many of
the special cases studied in the literature and allows for capturing the common
features shared by them. Here, we focus on three special cases, namely 1) Relay
Channel, 2) Multicast Channel, and 3) Conference Channel. These special cases
are judicially chosen to reflect varying degrees of complexity while
highlighting the common ground shared by the different variants of the three
node wireless network. For the relay channel, we propose a new cooperation
scheme that exploits the wireless feedback gain. This scheme combines the
benefits of decode-and-forward and compress-and-forward strategies and avoids
the idealistic feedback assumption adopted in earlier works. Our analysis of
the achievable rate of this scheme reveals the diminishing feedback gain at
both the low and high signal-to-noise ratio regimes. Inspired by the proposed
feedback strategy, we identify a greedy cooperation framework applicable to
both the multicast and conference channels. Our performance analysis reveals
several nice properties of the proposed greedy approach and the central role of
cooperative source-channel coding in exploiting the receiver side information
in the wireless network setting. Our proofs for the cooperative multicast with
side-information rely on novel nested and independent binning encoders along
with a list decoder.Comment: 52 page
Rate regions for coherent and noncoherent multisource network error correction
In this paper we derive capacity regions for network error correction with both known and unknown topologies (coherent and non-coherent network coding) under a multiple-source multicast transmission scenario. For the multiple-source non-multicast scenario, given any achievable network code for the error-free case, we construct a code with a reduced rate region for the case with errors
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