193,664 research outputs found
Rate Regions for the Partially-Cooperative Relay Broadcast Channel with Non-causal Side Information
In this work, we consider a partially cooperative relay broadcast channel
(PC-RBC) controlled by random parameters. We provide rate regions for two
different situations: 1) when side information (SI) S^n on the random
parameters is non-causally known at both the source and the relay and, 2) when
side information S^n is non-causally known at the source only. These achievable
regions are derived for the general discrete memoryless case first and then
extended to the case when the channel is degraded Gaussian and the SI is
additive i.i.d. Gaussian. In this case, the source uses generalized dirty paper
coding (GDPC), i.e., DPC combined with partial state cancellation, when only
the source is informed, and DPC alone when both the source and the relay are
informed. It appears that, even though it can not completely eliminate the
effect of the SI (in contrast to the case of source and relay being informed),
GDPC is particularly useful when only the source is informed.Comment: 7 pages, Proc. of IEEE International Symposium on Information theory,
ISIT 2007, Nice, Franc
Lossy Source Transmission over the Relay Channel
Lossy transmission over a relay channel in which the relay has access to
correlated side information is considered. First, a joint source-channel
decode-and-forward scheme is proposed for general discrete memoryless sources
and channels. Then the Gaussian relay channel where the source and the side
information are jointly Gaussian is analyzed. For this Gaussian model, several
new source-channel cooperation schemes are introduced and analyzed in terms of
the squared-error distortion at the destination. A comparison of the proposed
upper bounds with the cut-set lower bound is given, and it is seen that joint
source-channel cooperation improves the reconstruction quality significantly.
Moreover, the performance of the joint code is close to the lower bound on
distortion for a wide range of source and channel parameters.Comment: Proceedings of the 2008 IEEE International Symposium on Information
Theory, Toronto, ON, Canada, July 6 - 11, 200
On Joint Source-Channel Coding for Correlated Sources Over Multiple-Access Relay Channels
We study the transmission of correlated sources over discrete memoryless (DM)
multiple-access-relay channels (MARCs), in which both the relay and the
destination have access to side information arbitrarily correlated with the
sources. As the optimal transmission scheme is an open problem, in this work we
propose a new joint source-channel coding scheme based on a novel combination
of the correlation preserving mapping (CPM) technique with Slepian-Wolf (SW)
source coding, and obtain the corresponding sufficient conditions. The proposed
coding scheme is based on the decode-and-forward strategy, and utilizes CPM for
encoding information simultaneously to the relay and the destination, whereas
the cooperation information from the relay is encoded via SW source coding. It
is shown that there are cases in which the new scheme strictly outperforms the
schemes available in the literature. This is the first instance of a
source-channel code that uses CPM for encoding information to two different
nodes (relay and destination). In addition to sufficient conditions, we present
three different sets of single-letter necessary conditions for reliable
transmission of correlated sources over DM MARCs. The newly derived conditions
are shown to be at least as tight as the previously known necessary conditions.Comment: Accepted to TI
Interactive Relay Assisted Source Coding
This paper investigates a source coding problem in which two terminals
communicating through a relay wish to estimate one another's source within some
distortion constraint. The relay has access to side information that is
correlated with the sources. Two different schemes based on the order of
communication, \emph{distributed source coding/delivery} and \emph{two cascaded
rounds}, are proposed and inner and outer bounds for the resulting
rate-distortion regions are provided. Examples are provided to show that
neither rate-distortion region includes the other one.Comment: Invited Paper submitted to GlobalSIP: IEEE Global Conference on
Signal and Information Processing 201
On the Effective Capacity of Two-Hop Communication Systems
In this paper, two-hop communication between a source and a destination with
the aid of an intermediate relay node is considered. Both the source and
intermediate relay node are assumed to operate under statistical quality of
service (QoS) constraints imposed as limitations on the buffer overflow
probabilities. It is further assumed that the nodes send the information at
fixed power levels and have perfect channel side information. In this scenario,
the maximum constant arrival rates that can be supported by this two-hop link
are characterized by finding the effective capacity. Through this analysis, the
impact upon the throughput of having buffer constraints at the source and
intermediate-hop nodes is identified.Comment: submitted to ICC 201
Cellular Systems with Full-Duplex Compress-and-Forward Relaying and Cooperative Base Stations
In this paper the advantages provided by multicell processing of signals
transmitted by mobile terminals (MTs) which are received via dedicated relay
terminals (RTs) are studied. It is assumed that each RT is capable of
full-duplex operation and receives the transmission of adjacent relay
terminals. Focusing on intra-cell TDMA and non-fading channels, a simplified
relay-aided uplink cellular model based on a model introduced by Wyner is
considered. Assuming a nomadic application in which the RTs are oblivious to
the MTs' codebooks, a form of distributed compress-and-forward (CF) scheme with
decoder side information is employed. The per-cell sum-rate of the CF scheme is
derived and is given as a solution of a simple fixed point equation. This
achievable rate reveals that the CF scheme is able to completely eliminate the
inter-relay interference, and it approaches a ``cut-set-like'' upper bound for
strong RTs transmission power. The CF rate is also shown to surpass the rate of
an amplify-and-forward scheme via numerical calculations for a wide range of
the system parameters.Comment: Proceedings of the 2008 IEEE International Symposium on Information
Theory, Toronto, ON, Canada, July 6 - 11, 200
Robust MMSE Precoding Strategy for Multiuser MIMO Relay Systems with Switched Relaying and Side Information
In this work, we propose a minimum mean squared error (MMSE) robust base station (BS) precoding strategy based on switched relaying (SR) processing and limited transmission of side information for interference suppression in the downlink of multiuser multiple-input multiple-output (MIMO) relay systems. The BS and the MIMO relay station (RS) are both equipped with a codebook of interleaving matrices. For a given channel state information (CSI) the selection function at the BS chooses the optimum interleaving matrix from the codebook based on two optimization criteria to design the robust precoder. Prior to the payload transmission the BS sends the index corresponding to the selected interleaving matrix to the RS, where the best interleaving matrix is selected to build the optimum relay processing matrix. The entries of the codebook are randomly generated unitary matrices. Simulation results show that the performance of the proposed techniques is significantly better than prior art in the case of imperfect CSI.
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