17,289 research outputs found
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
Spatially-Coupled LDPC Codes for Decode-and-Forward Relaying of Two Correlated Sources over the BEC
We present a decode-and-forward transmission scheme based on
spatially-coupled low-density parity-check (SC-LDPC) codes for a network
consisting of two (possibly correlated) sources, one relay, and one
destination. The links between the nodes are modeled as binary erasure
channels. Joint source-channel coding with joint channel decoding is used to
exploit the correlation. The relay performs network coding. We derive
analytical bounds on the achievable rates for the binary erasure time-division
multiple-access relay channel with correlated sources. We then design bilayer
SC-LDPC codes and analyze their asymptotic performance for this scenario. We
prove analytically that the proposed coding scheme achieves the theoretical
limit for symmetric channel conditions and uncorrelated sources. Using density
evolution, we furthermore demonstrate that our scheme approaches the
theoretical limit also for non-symmetric channel conditions and when the
sources are correlated, and we observe the threshold saturation effect that is
typical for spatially-coupled systems. Finally, we give simulation results for
large block lengths, which validate the DE analysis.Comment: IEEE Transactions on Communications, to appea
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
Data mixing at the source, relay, and in the air in multiple-access relay networks
The concept of cooperative relay is an essential technique for future cellular networks such as wireless mesh networking or wireless ad-hoc networking. In a practical relay network, channel coding, network coding, and antenna arrays, will coexist and yet the joint optimization of these conventional coding schemes and cooperative relay is not well understood. To build a design guideline for relay network, this dissertation develop a joint optimization methodology for multiple coding schemes in multiple access relay network.
There are four major contributions in this thesis: First, we jointly optimize conventional coding schemes and radio resources of multiple access relay network with multiple antennas. The combined design of MIMO transmission modes, channel coding at the source, network coding at the relay have been investigated. We develop optimal design rule that minimize the end-to-end error probability. Second, we derive the fundamental tradeoff between achievable rate and reliability of multiple access relay network with multiple antennas. We consider three MIMO transmission modes, spatial multiplexing (SM), Alamouti coding as transmit diversity (TD), and Golden Coding, and random linear network coding at the relay. We compare the average decoding error probability of each transmission mode. Third, we present an interference cancellation scheme for multi-user MIMO. The proposed Log-likelihood-ratio (LLR) ordered successive interference cancellation (SIC) scheme provides 1 ~ 3 dB gain over the conventional SNR-ordered SIC and the gain increases with increasing number of users. Finally, we present a new architecture for MIMO receivers that cancel the co-channel interference (CCI) using a single radio frequency (RF) and baseband (BB) chain, while still achieving nearly the same bit error rate that can be provided by the conventional receiver requiring multiple RF/BB chains
On the Design of a Novel Joint Network-Channel Coding Scheme for the Multiple Access Relay Channel
This paper proposes a novel joint non-binary network-channel code for the
Time-Division Decode-and-Forward Multiple Access Relay Channel (TD-DF-MARC),
where the relay linearly combines -- over a non-binary finite field -- the
coded sequences from the source nodes. A method based on an EXIT chart analysis
is derived for selecting the best coefficients of the linear combination.
Moreover, it is shown that for different setups of the system, different
coefficients should be chosen in order to improve the performance. This
conclusion contrasts with previous works where a random selection was
considered. Monte Carlo simulations show that the proposed scheme outperforms,
in terms of its gap to the outage probabilities, the previously published joint
network-channel coding approaches. Besides, this gain is achieved by using very
short-length codewords, which makes the scheme particularly attractive for
low-latency applications.Comment: 28 pages, 9 figures; Submitted to IEEE Journal on Selected Areas in
Communications - Special Issue on Theories and Methods for Advanced Wireless
Relays, 201
- …