13,950 research outputs found
Cooperative Binning for Semi-deterministic Channels with Non-causal State Information
The capacity of the semi-deterministic relay channel (SD-RC) with non-causal
channel state information (CSI) only at the encoder and decoder is
characterized. The capacity is achieved by a scheme based on
cooperative-bin-forward. This scheme allows cooperation between the transmitter
and the relay without the need to decode a part of the message by the relay.
The transmission is divided into blocks and each deterministic output of the
channel (observed by the relay) is mapped to a bin. The bin index is used by
the encoder and the relay to choose the cooperation codeword in the next
transmission block. In causal settings the cooperation is independent of the
state. In \emph{non-causal} settings dependency between the relay's
transmission and the state can increase the transmission rates. The encoder
implicitly conveys partial state information to the relay. In particular, it
uses the states of the next block and selects a cooperation codeword
accordingly and the relay transmission depends on the cooperation codeword and
therefore also on the states. We also consider the multiple access channel with
partial cribbing as a semi-deterministic channel. The capacity region of this
channel with non-causal CSI is achieved by the new scheme. Examining the result
in several cases, we introduce a new problem of a point-to-point (PTP) channel
where the state is provided to the transmitter by a state encoder.
Interestingly, even though the CSI is also available at the receiver, we
provide an example which shows that the capacity with non-causal CSI at the
state encoder is strictly larger than the capacity with causal CSI
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
Trading Wireless Information and Power Transfer: Relay Selection to Minimize the Outage Probability
This paper studies the outage probability minimization problem for a multiple
relay network with energy harvesting constraints. The relays are hybrid nodes
used for simultaneous wireless information and power transfer from the source
radio frequency (RF) signals. There is a trade-off associated with the amount
of time a relay node is used for energy and information transfer. Large
intervals of information transfer implies little time for energy harvesting
from RF signals and thus, high probability of outage events. We propose relay
selection schemes for a cooperative system with a fixed number of RF powered
relays. We address both causal and non-causal channel state information cases
at the relay--destination link and evaluate the trade-off associated with
information/power transfer in the context of minimization of outage
probability.Comment: IEEE GlobalSiP, 201
Relay X Channels without Channel State Information at the Transmit Sides: Degrees of Freedom
This paper focuses on the two-user relay-assisted X channel with no channel state information (CSI) available at the transmitter side. Two relaying modes, namely half-duplex decode-and-forward (DF) and cognitive relays, are considered and the degrees of freedom (DoF) are characterized. It is shown that assisted by a half-duplex DF relay that is equipped with 2M antennas, the X channel with two M-antenna users has 4M/3 DoF, which is achievable through interference alignment (IA). Furthermore, it is shown that in this channel, an M-antenna cognitive relay (with non-causal access to information streams) provides 2M DoF using interference cancellation (IC) technique. In this setting, IC outperforms interference alignment in the cognitive relay mode, since the latter achieves 4M/3 DoF
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