9,574 research outputs found
An Extended Network Coding Opportunity Discovery Scheme in Wireless Networks
Network coding is known as a promising approach to improve wireless network
performance. How to discover the coding opportunity in relay nodes is really
important for it. There are more coding chances, there are more times it can
improve network throughput by network coding operation. In this paper, an
extended network coding opportunity discovery scheme (ExCODE) is proposed,
which is realized by appending the current node ID and all its 1-hop neighbors'
IDs to the packet. ExCODE enables the next hop relay node to know which nodes
else have already overheard the packet, so it can discover the potential coding
opportunities as much as possible. ExCODE expands the region of discovering
coding chance to n-hops, and have more opportunities to execute network coding
operation in each relay node. At last, we implement ExCODE over the AODV
protocol, and efficiency of the proposed mechanism is demonstrated with NS2
simulations, compared to the existing coding opportunity discovery scheme.Comment: 15 pages and 7 figure
On Capacity and Delay of Multi-channel Wireless Networks with Infrastructure Support
In this paper, we propose a novel multi-channel network with infrastructure
support, called an MC-IS network, which has not been studied in the literature.
To the best of our knowledge, we are the first to study such an MC-IS network.
Our proposed MC-IS network has a number of advantages over three existing
conventional networks, namely a single-channel wireless ad hoc network (called
an SC-AH network), a multi-channel wireless ad hoc network (called an MC-AH
network) and a single-channel network with infrastructure support (called an
SC-IS network). In particular, the network capacity of our proposed MC-IS
network is times higher than that of an SC-AH network and an
MC-AH network and the same as that of an SC-IS network, where is the number
of nodes in the network. The average delay of our MC-IS network is times lower than that of an SC-AH network and an MC-AH network, and
times lower than the average delay of an SC-IS network, where
and denote the number of channels dedicated for infrastructure
communications and the number of interfaces mounted at each infrastructure
node, respectively. Our analysis on an MC-IS network equipped with
omni-directional antennas only has been extended to an MC-IS network equipped
with directional antennas only, which are named as an MC-IS-DA network. We show
that an MC-IS-DA network has an even lower delay of compared with an SC-IS network and our
MC-IS network. For example, when and , an
MC-IS-DA network can further reduce the delay by 24 times lower that of an
MC-IS network and reduce the delay by 288 times lower than that of an SC-IS
network.Comment: accepted, IEEE Transactions on Vehicular Technology, 201
Throughput-Delay Trade-off for Hierarchical Cooperation in Ad Hoc Wireless Networks
Hierarchical cooperation has recently been shown to achieve better throughput
scaling than classical multihop schemes under certain assumptions on the
channel model in static wireless networks. However, the end-to-end delay of
this scheme turns out to be significantly larger than those of multihop
schemes. A modification of the scheme is proposed here that achieves a
throughput-delay trade-off for T(n) between
and , where D(n) and T(n) are
respectively the average delay per bit and the aggregate throughput in a
network of n nodes. This trade-off complements the previous results of El Gamal
et al., which show that the throughput-delay trade-off for multihop schemes is
given by D(n)=T(n) where T(n) lies between and .
Meanwhile, the present paper considers the network multiple-access problem,
which may be of interest in its own right.Comment: 9 pages, 6 figures, to appear in IEEE Transactions on Information
Theory, submitted Dec 200
PACE: Simple Multi-hop Scheduling for Single-radio 802.11-based Stub Wireless Mesh Networks
IEEE 802.11-based Stub Wireless Mesh Networks (WMNs) are a cost-effective and flexible solution to extend wired network infrastructures. Yet, they suffer from two major problems: inefficiency and unfairness. A number of approaches have been proposed to tackle these problems, but they are too restrictive, highly complex, or require time synchronization and modifications to the IEEE 802.11 MAC.
PACE is a simple multi-hop scheduling mechanism for Stub WMNs overlaid on the IEEE 802.11 MAC that jointly addresses the inefficiency and unfairness problems. It limits transmissions to a single mesh node at each time and ensures that each node has the opportunity to transmit a packet in each network-wide transmission round. Simulation results demonstrate that PACE can achieve optimal network capacity utilization and greatly outperforms state of the art CSMA/CA-based solutions as far as goodput, delay, and fairness are concerned
Scalability of broadcast performance in wireless network-on-chip
Networks-on-Chip (NoCs) are currently the paradigm of choice to interconnect the cores of a chip multiprocessor. However, conventional NoCs may not suffice to fulfill the on-chip communication requirements of processors with hundreds or thousands of cores. The main reason is that the performance of such networks drops as the number of cores grows, especially in the presence of multicast and broadcast traffic. This not only limits the scalability of current multiprocessor architectures, but also sets a performance wall that prevents the development of architectures that generate moderate-to-high levels of multicast. In this paper, a Wireless Network-on-Chip (WNoC) where all cores share a single broadband channel is presented. Such design is conceived to provide low latency and ordered delivery for multicast/broadcast traffic, in an attempt to complement a wireline NoC that will transport the rest of communication flows. To assess the feasibility of this approach, the network performance of WNoC is analyzed as a function of the system size and the channel capacity, and then compared to that of wireline NoCs with embedded multicast support. Based on this evaluation, preliminary results on the potential performance of the proposed hybrid scheme are provided, together with guidelines for the design of MAC protocols for WNoC.Peer ReviewedPostprint (published version
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