998 research outputs found
HARQ Feedback in Spectrum Sharing Networks
This letter studies the throughput and the outage probability of spectrum
sharing networks utilizing hybrid automatic repeat request (HARQ) feedback. We
focus on the repetition time diversity and the incremental redundancy HARQ
protocols where the results are obtained for both continuous and bursting
communication models. The channel data transmission efficiency is investigated
in the presence of both secondary user peak transmission power and primary user
received interference power constraints. Finally, we evaluate the effect of
secondary-primary channel state information imperfection on the performance of
the secondary channel. Simulation results show that, while the throughput is
not necessarily increased by HARQ, substantial outage probability reduction is
achieved in all conditions.Comment: Published in IEEE Communications Letter
Reinforcement-based data transmission in temporally-correlated fading channels: Partial CSIT scenario
Reinforcement algorithms refer to the schemes where the results of the
previous trials and a reward-punishment rule are used for parameter setting in
the next steps. In this paper, we use the concept of reinforcement algorithms
to develop different data transmission models in wireless networks. Considering
temporally-correlated fading channels, the results are presented for the cases
with partial channel state information at the transmitter (CSIT). As
demonstrated, the implementation of reinforcement algorithms improves the
performance of communication setups remarkably, with the same feedback
load/complexity as in the state-of-the-art schemes.Comment: Accepted for publication in ISWCS 201
Enabling Realistic Cross-Layer Analysis based on Satellite Physical Layer Traces
We present a solution to evaluate the performance of transport protocols as a function of link layer reliability schemes (i.e. ARQ, FEC and Hybrid ARQ) applied to satellite physical layer traces. As modelling such traces is complex and may require approximations, the use of real traces will minimise the potential for erroneous performance evaluations resulting from imperfect models. Our Trace Manager Tool (TMT) produces the corresponding link layer output, which is then used within the ns-2 network simulator via the additionally developed ns-2 interface module. We first present the analytical models for the link layer with bursty erasure packets and for the link layer reliability mechanisms with bursty erasures. Then, we present details of the TMT tool and our validation methodology, demonstrating that the selected performance metrics (recovery delay and throughput efficiency) exhibit a good match between the theoretical results and those obtained with TMT. Finally, we present results showing the impact of different link layer reliability mechanisms on the performance of TCP Cubic transport layer protocol
Enabling Realistic Cross-Layer Analysis based on Satellite Physical Layer Traces
We present a solution to evaluate the performance of transport protocols as a
function of link layer reliability schemes (i.e. ARQ, FEC and Hybrid ARQ)
applied to satellite physical layer traces. As modelling such traces is complex
and may require approximations, the use of real traces will minimise the
potential for erroneous performance evaluations resulting from imperfect
models. Our Trace Manager Tool (TMT) produces the corresponding link layer
output, which is then used within the ns-2 network simulator via the
additionally developed ns-2 interface module. We first present the analytical
models for the link layer with bursty erasure packets and for the link layer
reliability mechanisms with bursty erasures. Then, we present details of the
TMT tool and our validation methodology, demonstrating that the selected
performance metrics (recovery delay and throughput efficiency) exhibit a good
match between the theoretical results and those obtained with TMT. Finally, we
present results showing the impact of different link layer reliability
mechanisms on the performance of TCP Cubic transport layer protocol.Comment: 6 pages, 5 figures and 1 table. Submitted at PIMRC 201
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