Abstract:
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We consider the orthogonal multiple relay channel at the low
SNR regime.The source transmits to the destination and all the
possible relays in one channel and the relays transmit in different
and orthogonal channels making use of the transmission received
from the source. This cooperative strategy achieves diversity gains
at a high cost in bandwidth efficiency, due to the orthogonality of
the transmissions. However, it has the desired benefit of allowing
all the nodes in the network to behave as in a point to point
channel. Based on the max-flow min-cut upper bound for relay
networks, we explore the capacity limits of this kind of communication,
obtaining an upper bound on the capacity when full channel
state information (CSI) is available at every network node. This
focus gives insight on the design of the transmitting strategy and
define how feedback from relays and destination can be performed
practically and optimally, giving ideas for higher layer protocols. |