1,883 research outputs found
State-Dependent Relay Channel with Private Messages with Partial Causal and Non-Causal Channel State Information
In this paper, we introduce a discrete memoryless State-Dependent Relay
Channel with Private Messages (SD-RCPM) as a generalization of the
state-dependent relay channel. We investigate two main cases: SD-RCPM with
non-causal Channel State Information (CSI), and SD-RCPM with causal CSI. In
each case, it is assumed that partial CSI is available at the source and relay.
For non-causal case, we establish an achievable rate region using
Gel'fand-Pinsker type coding scheme at the nodes informed of CSI, and
Compress-and-Forward (CF) scheme at the relay. Using Shannon's strategy and CF
scheme, an achievable rate region for causal case is obtained. As an example,
the Gaussian version of SD-RCPM is considered, and an achievable rate region
for Gaussian SD-RCPM with non-causal perfect CSI only at the source, is
derived. Providing numerical examples, we illustrate the comparison between
achievable rate regions derived using CF and Decode-and-Forward (DF) schemes.Comment: 5 pages, 2 figures, to be presented at the IEEE International
Symposium on Information Theory (ISIT 2010), Austin, Texas, June 201
Polar Codes over Fading Channels with Power and Delay Constraints
The inherent nature of polar codes being channel specific makes it difficult
to use them in a setting where the communication channel changes with time. In
particular, to be able to use polar codes in a wireless scenario, varying
attenuation due to fading needs to be mitigated. To the best of our knowledge,
there has been no comprehensive work in this direction thus far. In this work,
a practical scheme involving channel inversion with the knowledge of the
channel state at the transmitter, is proposed. An additional practical
constraint on the permissible average and peak power is imposed, which in turn
makes the channel equivalent to an additive white Gaussian noise (AWGN) channel
cascaded with an erasure channel. It is shown that the constructed polar code
could be made to achieve the symmetric capacity of this channel. Further, a
means to compute the optimal design rate of the polar code for a given power
constraint is also discussed.Comment: 6 pages, 6 figure
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