11,759 research outputs found
A Unified Scheme for Two-Receiver Broadcast Channels with Receiver Message Side Information
This paper investigates the capacity regions of two-receiver broadcast
channels where each receiver (i) has both common and private-message requests,
and (ii) knows part of the private message requested by the other receiver as
side information. We first propose a transmission scheme and derive an inner
bound for the two-receiver memoryless broadcast channel. We next prove that
this inner bound is tight for the deterministic channel and the more capable
channel, thereby establishing their capacity regions. We show that this inner
bound is also tight for all classes of two-receiver broadcast channels whose
capacity regions were known prior to this work. Our proposed scheme is
consequently a unified capacity-achieving scheme for these classes of broadcast
channels.Comment: accepted and to be presented at the 2015 IEEE International Symposium
on Information Theory (ISIT 2015
The capacity region of classes of product broadcast channels
We establish a new outer bound for the capacity region of product broadcast
channels. This outer bound matches Marton's inner bound for a variety of
classes of product broadcast channels whose capacity regions were previously
unknown. These classes include product of reversely semi-deterministic and
product of reversely more-capable channels. A significant consequence of this
new outer bound is that it establishes, via an example, that the previously
best known outer-bound is strictly suboptimal for the general broadcast
channel. Our example is comprised of a product broadcast channel with two
semi-deterministic components in reverse orientation.Comment: full version of isit pape
A Comparison of Superposition Coding Schemes
There are two variants of superposition coding schemes. Cover's original
superposition coding scheme has code clouds of the identical shape, while
Bergmans's superposition coding scheme has code clouds of independently
generated shapes. These two schemes yield identical achievable rate regions in
several scenarios, such as the capacity region for degraded broadcast channels.
This paper shows that under the optimal maximum likelihood decoding, these two
superposition coding schemes can result in different rate regions. In
particular, it is shown that for the two-receiver broadcast channel, Cover's
superposition coding scheme can achieve rates strictly larger than Bergmans's
scheme.Comment: 5 pages, 3 figures, 1 table, submitted to IEEE International
Symposium on Information Theory (ISIT 2013
Achieving Marton's Region for Broadcast Channels Using Polar Codes
This paper presents polar coding schemes for the 2-user discrete memoryless
broadcast channel (DM-BC) which achieve Marton's region with both common and
private messages. This is the best achievable rate region known to date, and it
is tight for all classes of 2-user DM-BCs whose capacity regions are known. To
accomplish this task, we first construct polar codes for both the superposition
as well as the binning strategy. By combining these two schemes, we obtain
Marton's region with private messages only. Finally, we show how to handle the
case of common information. The proposed coding schemes possess the usual
advantages of polar codes, i.e., they have low encoding and decoding complexity
and a super-polynomial decay rate of the error probability.
We follow the lead of Goela, Abbe, and Gastpar, who recently introduced polar
codes emulating the superposition and binning schemes. In order to align the
polar indices, for both schemes, their solution involves some degradedness
constraints that are assumed to hold between the auxiliary random variables and
the channel outputs. To remove these constraints, we consider the transmission
of blocks and employ a chaining construction that guarantees the proper
alignment of the polarized indices. The techniques described in this work are
quite general, and they can be adopted to many other multi-terminal scenarios
whenever there polar indices need to be aligned.Comment: 26 pages, 11 figures, accepted to IEEE Trans. Inform. Theory and
presented in part at ISIT'1
- …