26,899 research outputs found
On lossy transmission of correlated sources over a multiple access channel
We study lossy communication of correlated sources over a multiple access channel. In particular, we provide a joint source-channel coding scheme for transmitting correlated sources with decoder side information, and study the conditions under which separate source and channel coding is optimal. For the latter, the encoders and/or the decoder have access to a common observation conditioned on which the two sources are independent. By establishing necessary and sufficient conditions, we show the optimality of separation when the encoders and the decoder both have access to the common observation. We also demonstrate that separation is optimal when only the encoders have access to the common observation whose lossless recovery is required at the decoder. As a special case, we study separation for sources with a common part. Our results indicate that side information can have significant impact on the optimality of source-channel separation in lossy transmission
Joint Source-Channel Coding for Broadcast Channel with Cooperating Receivers
It is known that, as opposed to point-to-point channel, separate source and
channel coding is not optimal in general for sending correlated sources over
multiuser channels. In some works joint source-channel coding has been
investigated for some certain multiuser channels; i.g., multiple access channel
(MAC) and broadcast channel (BC). In this paper, we obtain a sufficient
condition for transmitting arbitrarily correlated sources over a discrete
memoryless BC with cooperating receivers, where the receivers are allowed to
exchange messages via a pair of noisy cooperative links. It is seen that our
results is a general form of previous ones and includes them as its special
cases.Comment: to appear in Proceedings of IEEE Information Theory Workshop - Fall
(ITW'2015
Source-Channel Coding for the Multiple-Access Relay Channel
This work considers reliable transmission of general correlated sources over
the multiple-access relay channel (MARC) and the multiple-access broadcast
relay channel (MABRC). In MARCs only the destination is interested in a
reconstruction of the sources, while in MABRCs both the relay and the
destination want to reconstruct the sources. We assume that both the relay and
the destination have correlated side information. We find sufficient conditions
for reliable communication based on operational separation, as well as
necessary conditions on the achievable source-channel rate. For correlated
sources transmitted over fading Gaussian MARCs and MABRCs we find conditions
under which informational separation is optimal.Comment: Presented in ISWCS 2011, Aachen, German
Source-Channel Coding Theorems for the Multiple-Access Relay Channel
We study reliable transmission of arbitrarily correlated sources over
multiple-access relay channels (MARCs) and multiple-access broadcast relay
channels (MABRCs). In MARCs only the destination is interested in
reconstructing the sources, while in MABRCs both the relay and the destination
want to reconstruct them. In addition to arbitrary correlation among the source
signals at the users, both the relay and the destination have side information
correlated with the source signals. Our objective is to determine whether a
given pair of sources can be losslessly transmitted to the destination for a
given number of channel symbols per source sample, defined as the
source-channel rate. Sufficient conditions for reliable communication based on
operational separation, as well as necessary conditions on the achievable
source-channel rates are characterized. Since operational separation is
generally not optimal for MARCs and MABRCs, sufficient conditions for reliable
communication using joint source-channel coding schemes based on a combination
of the correlation preserving mapping technique with Slepian-Wolf source coding
are also derived. For correlated sources transmitted over fading Gaussian MARCs
and MABRCs, we present conditions under which separation (i.e., separate and
stand-alone source and channel codes) is optimal. This is the first time
optimality of separation is proved for MARCs and MABRCs.Comment: Accepted to IEEE Transaction on Information Theor
Interference Channel with a Half-Duplex Out-of-Band Relay
A Gaussian interference channel (IC) aided by a half-duplex relay is
considered, in which the relay receives and transmits in an orthogonal band
with respect to the IC. The system thus consists of two parallel channels, the
IC and the channel over which the relay is active, which is referred to as
Out-of-Band Relay Channel (OBRC). The OBRC is operated by separating a multiple
access phase from the sources to the relay and a broadcast phase from the relay
to the destinations. Conditions under which the optimal operation, in terms of
the sum-capacity, entails either signal relaying and/or interference forwarding
by the relay are identified. These conditions also assess the optimality of
either separable or non-separable transmission over the IC and OBRC.
Specifically, the optimality of signal relaying and separable coding is
established for scenarios where the relay-to-destination channels set the
performance bottleneck with respect to the source-to-relay channels on the
OBRC. Optimality of interference forwarding and non-separable operation is also
established in special cases.Comment: 5 pages, 5 figures, to appear in Proceedings of IEEE ISIT 201
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