28,201 research outputs found
General Model for Infrastructure Multi-channel Wireless LANs
In this paper we develop an integrated model for request mechanism and data
transmission in multi-channel wireless local area networks. We calculated the
performance parameters for single and multi-channel wireless networks when the
channel is noisy. The proposed model is general it can be applied to different
wireless networks such as IEEE802.11x, IEEE802.16, CDMA operated networks and
Hiperlan\2.Comment: 11 Pages, IJCN
Flow Allocation for Maximum Throughput and Bounded Delay on Multiple Disjoint Paths for Random Access Wireless Multihop Networks
In this paper, we consider random access, wireless, multi-hop networks, with
multi-packet reception capabilities, where multiple flows are forwarded to the
gateways through node disjoint paths. We explore the issue of allocating flow
on multiple paths, exhibiting both intra- and inter-path interference, in order
to maximize average aggregate flow throughput (AAT) and also provide bounded
packet delay. A distributed flow allocation scheme is proposed where allocation
of flow on paths is formulated as an optimization problem. Through an
illustrative topology it is shown that the corresponding problem is non-convex.
Furthermore, a simple, but accurate model is employed for the average aggregate
throughput achieved by all flows, that captures both intra- and inter-path
interference through the SINR model. The proposed scheme is evaluated through
Ns2 simulations of several random wireless scenarios. Simulation results reveal
that, the model employed, accurately captures the AAT observed in the simulated
scenarios, even when the assumption of saturated queues is removed. Simulation
results also show that the proposed scheme achieves significantly higher AAT,
for the vast majority of the wireless scenarios explored, than the following
flow allocation schemes: one that assigns flows on paths on a round-robin
fashion, one that optimally utilizes the best path only, and another one that
assigns the maximum possible flow on each path. Finally, a variant of the
proposed scheme is explored, where interference for each link is approximated
by considering its dominant interfering nodes only.Comment: IEEE Transactions on Vehicular Technolog
Relay-assisted Multiple Access with Full-duplex Multi-Packet Reception
The effect of full-duplex cooperative relaying in a random access multiuser
network is investigated here. First, we model the self-interference incurred
due to full-duplex operation, assuming multi-packet reception capabilities for
both the relay and the destination node. Traffic at the source nodes is
considered saturated and the cooperative relay, which does not have packets of
its own, stores a source packet that it receives successfully in its queue when
the transmission to the destination has failed. We obtain analytical
expressions for key performance metrics at the relay, such as arrival and
service rates, stability conditions, and average queue length, as functions of
the transmission probabilities, the self interference coefficient, and the
links' outage probabilities. Furthermore, we study the impact of the relay node
and the self-interference coefficient on the per-user and aggregate throughput,
and the average delay per packet. We show that perfect self-interference
cancelation plays a crucial role when the SINR threshold is small, since it may
result to worse performance in throughput and delay comparing with the
half-duplex case. This is because perfect self-interference cancelation can
cause an unstable queue at the relay under some conditions.Comment: Accepted for publication in the IEEE Transactions on Wireless
Communication
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