10,819 research outputs found
Perfect Output Feedback in the Two-User Decentralized Interference Channel
In this paper, the -Nash equilibrium (-NE) region of the two-user
Gaussian interference channel (IC) with perfect output feedback is approximated
to within bit/s/Hz and arbitrarily close to bit/s/Hz. The
relevance of the -NE region is that it provides the set of rate-pairs
that are achievable and stable in the IC when both transmitter-receiver pairs
autonomously tune their own transmit-receive configurations seeking an
-optimal individual transmission rate. Therefore, any rate tuple outside
the -NE region is not stable as there always exists one link able to
increase by at least bits/s/Hz its own transmission rate by updating its
own transmit-receive configuration. The main insights that arise from this work
are: The -NE region achieved with feedback is larger than or equal
to the -NE region without feedback. More importantly, for each rate pair
achievable at an -NE without feedback, there exists at least one rate
pair achievable at an -NE with feedback that is weakly Pareto superior.
There always exists an -NE transmit-receive configuration that
achieves a rate pair that is at most bit/s/Hz per user away from the outer
bound of the capacity region.Comment: Revised version (Aug. 2015
Incremental Relaying for the Gaussian Interference Channel with a Degraded Broadcasting Relay
This paper studies incremental relay strategies for a two-user Gaussian
relay-interference channel with an in-band-reception and
out-of-band-transmission relay, where the link between the relay and the two
receivers is modelled as a degraded broadcast channel. It is shown that
generalized hash-and-forward (GHF) can achieve the capacity region of this
channel to within a constant number of bits in a certain weak relay regime,
where the transmitter-to-relay link gains are not unboundedly stronger than the
interference links between the transmitters and the receivers. The GHF relaying
strategy is ideally suited for the broadcasting relay because it can be
implemented in an incremental fashion, i.e., the relay message to one receiver
is a degraded version of the message to the other receiver. A
generalized-degree-of-freedom (GDoF) analysis in the high signal-to-noise ratio
(SNR) regime reveals that in the symmetric channel setting, each common relay
bit can improve the sum rate roughly by either one bit or two bits
asymptotically depending on the operating regime, and the rate gain can be
interpreted as coming solely from the improvement of the common message rates,
or alternatively in the very weak interference regime as solely coming from the
rate improvement of the private messages. Further, this paper studies an
asymmetric case in which the relay has only a single single link to one of the
destinations. It is shown that with only one relay-destination link, the
approximate capacity region can be established for a larger regime of channel
parameters. Further, from a GDoF point of view, the sum-capacity gain due to
the relay can now be thought as coming from either signal relaying only, or
interference forwarding only.Comment: To appear in IEEE Trans. on Inf. Theor
An Achievable Rate Region for Three-Pair Interference Channels with Noise
An achievable rate region for certain noisy three-user-pair interference
channels is proposed. The channel class under consideration generalizes the
three-pair deterministic interference channel (3-DIC) in the same way as the
Telatar-Tse noisy two-pair interference channel generalizes the El Gamal-Costa
injective channel. Specifically, arbitrary noise is introduced that acts on the
combined interference signal before it affects the desired signal. This class
of channels includes the Gaussian case.
The rate region includes the best-known inner bound on the 3-DIC capacity
region, dominates treating interference as noise, and subsumes the
Han-Kobayashi region for the two-pair case.Comment: 9 pages, 3 figures; abbreviated version to be presented at IEEE
International Symposium on Information Theory (ISIT 2012
Distributed Full-duplex via Wireless Side Channels: Bounds and Protocols
In this paper, we study a three-node full-duplex network, where a base
station is engaged in simultaneous up- and downlink communication in the same
frequency band with two half-duplex mobile nodes. To reduce the impact of
inter- node interference between the two mobile nodes on the system capacity,
we study how an orthogonal side-channel between the two mobile nodes can be
leveraged to achieve full-duplex-like multiplexing gains. We propose and
characterize the achievable rates of four distributed full-duplex schemes,
labeled bin-and- cancel, compress-and-cancel, estimate-and-cancel and decode-
and-cancel. Of the four, bin-and-cancel is shown to achieve within 1 bit/s/Hz
of the capacity region for all values of channel parameters. In contrast, the
other three schemes achieve the near-optimal performance only in certain
regimes of channel values. Asymptotic multiplexing gains of all proposed
schemes are derived to show that the side-channel is extremely effective in
regimes where inter-node interference has the highest impact.Comment: Published in IEEE Transactions on Wireless Communications, August
201
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