670 research outputs found
A Comparative Study of Relaying Schemes with Decode-and-Forward over Nakagami-m Fading Channels
Utilizing relaying techniques to improve performance of wireless systems is a
promising avenue. However, it is crucial to understand what type of relaying
schemes should be used for achieving different performance objectives under
realistic fading conditions. In this paper, we present a general framework for
modelling and evaluating the performance of relaying schemes based on the
decode-and-forward (DF) protocol over independent and not necessarily
identically distributed (INID) Nakagami-m fading channels. In particular, we
present closed-form expressions for the statistics of the instantaneous output
signal-to-noise ratio of four significant relaying schemes with DF; two based
on repetitive transmission and the other two based on relay selection (RS).
These expressions are then used to obtain closed-form expressions for the
outage probability and the average symbol error probability for several
modulations of all considered relaying schemes over INID Nakagami-m fading.
Importantly, it is shown that when the channel state information for RS is
perfect, RS-based transmission schemes always outperform repetitive ones.
Furthermore, when the direct link between the source and the destination nodes
is sufficiently strong, relaying may not result in any gains and in this case
it should be switched-off.Comment: Submitted to Journal of Computer Systems, Networks, and
Communication
Error Rate Analysis of GF(q) Network Coded Detect-and-Forward Wireless Relay Networks Using Equivalent Relay Channel Models
This paper investigates simple means of analyzing the error rate performance
of a general q-ary Galois Field network coded detect-and-forward cooperative
relay network with known relay error statistics at the destination. Equivalent
relay channels are used in obtaining an approximate error rate of the relay
network, from which the diversity order is found. Error rate analyses using
equivalent relay channel models are shown to be closely matched with simulation
results. Using the equivalent relay channels, low complexity receivers are
developed whose performances are close to that of the optimal maximum
likelihood receiver.Comment: 28 pages, 10 figures. This work has been submitted to the IEEE for
possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl
On the Performance of Multiple Antenna Cooperative Spectrum Sharing Protocol under Nakagami-m Fading
In a cooperative spectrum sharing (CSS) protocol, two wireless systems
operate over the same frequency band albeit with different priorities. The
secondary (or cognitive) system which has a lower priority, helps the higher
priority primary system to achieve its target rate by acting as a relay and
allocating a fraction of its power to forward the primary signal. The secondary
system in return is benefited by transmitting its own data on primary system's
spectrum. In this paper, we have analyzed the performance of multiple antenna
cooperative spectrum sharing protocol under Nakagami-m Fading. Closed form
expressions for outage probability have been obtained by varying the parameters
m and Omega of the Nakagami-m fading channels. Apart from above, we have shown
the impact of power allocation factor (alpha) and parameter m on the region of
secondary spectrum access, conventionally defined as critical radius for the
secondary system. A comparison between theoretical and simulated results is
also presented to corroborate the theoretical results obtained in this paperComment: Accepted in the proceedings of IEEE PIMRC 2015 Hong Kong, Chin
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