1,963 research outputs found
Experimentation with MANETs of Smartphones
Mobile AdHoc NETworks (MANETs) have been identified as a key emerging
technology for scenarios in which IEEE 802.11 or cellular communications are
either infeasible, inefficient, or cost-ineffective. Smartphones are the most
adequate network nodes in many of these scenarios, but it is not
straightforward to build a network with them. We extensively survey existing
possibilities to build applications on top of ad-hoc smartphone networks for
experimentation purposes, and introduce a taxonomy to classify them. We present
AdHocDroid, an Android package that creates an IP-level MANET of (rooted)
Android smartphones, and make it publicly available to the community.
AdHocDroid supports standard TCP/IP applications, providing real smartphone
IEEE 802.11 MANET and the capability to easily change the routing protocol. We
tested our framework on several smartphones and a laptop. We validate the MANET
running off-the-shelf applications, and reporting on experimental performance
evaluation, including network metrics and battery discharge rate.Comment: 6 pages, 7 figures, 1 tabl
WIMAX Basics from PHY Layer to Scheduling and Multicasting Approaches
WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations
Wireless industrial monitoring and control networks: the journey so far and the road ahead
While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks
Layer 2 Path Selection Protocol for Wireless Mesh Networks with Smart Antennas
In this thesis the possibilities of smart antenna systems in wireless mesh networks are examined. With respect to the individual smart antenna tradeoffs, a routing protocol (Modified HWMP, MHWMP) for IEEE 802.11s mesh networks is presented, that exploits the full range of benefits provided by smart antennas: MHWMP actively switches between the PHY-layer transmission/reception modes (multiplexing, beamforming and diversity) according to the wireless channel conditions. Spatial multiplexing and beamforming are used for unicast data transmissions, while antenna diversity is employed for efficient broadcasts. To adapt to the directional channel environment and to take full benefit of the PHY capabilities, a respective MAC scheme is employed. The presented protocol is tested in extensive simulation and the results are examined.:1 Introduction
2 Wireless Mesh Networks
3 IEEE 802.11s
4 Smart Antenna Concepts
5 State of the Art: Wireless Mesh Networks with Smart Antennas
6 New Concepts
7 System Model
8 Results and Discussion
9 Conclusion and Future Wor
A Survey on Scheduling in IEEE 802.16 Mesh Mode
Cataloged from PDF version of article.IEEE 802.16 standard (also known as WiMAX)
defines the wireless broadband network technology which aims
to solve the so called last mile problem via providing high
bandwidth Internet even to the rural areas for which the cable
deployment is very costly. The standard mainly focuses on the
MAC and PHY layer issues, supporting two transmission modes:
PMP (Point-to-Multipoint) and mesh modes. Mesh mode is an
optional mode developed as an extension to PMP mode and it
has the advantage of having an improving performance as more
subscribers are added to the system using multi-hop routes. In
802.16 MAC protocol, mesh mode slot allocation and reservation
mechanisms are left open which makes this topic a hot research
area. Hence, the focus of this survey will mostly be on the mesh
mode, and the proposed scheduling algorithms and performance
evaluation methods
On Modeling and Analysis of MIMO Wireless Mesh Networks with Triangular Overlay Topology
Multiple input multiple output (MIMO) wireless
mesh networks (WMNs) aim to provide the last-mile broadband
wireless access to the Internet. Along with the algorithmic development
for WMNs, some fundamental mathematical problems
also emerge in various aspects such as routing, scheduling, and
channel assignment, all of which require an effective mathematical
model and rigorous analysis of network properties. In
this paper, we propose to employ Cartesian product of graphs
(CPG) as a multichannel modeling approach and explore a
set of unique properties of triangular WMNs. In each layer of
CPG with a single channel, we design a node coordinate scheme
that retains the symmetric property of triangular meshes and
develop a function for the assignment of node identity numbers
based on their coordinates. We also derive a necessary-sufficient
condition for interference-free links and combinatorial formulas
to determine the number of the shortest paths for channel
realization in triangular WMNs
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