5,217 research outputs found
LPDQ: a self-scheduled TDMA MAC protocol for one-hop dynamic lowpower wireless networks
Current Medium Access Control (MAC) protocols for data collection scenarios with a large number of nodes that generate bursty traffic are based on Low-Power Listening (LPL) for network synchronization and Frame Slotted ALOHA (FSA) as the channel access mechanism. However, FSA has an efficiency bounded to 36.8% due to contention effects, which reduces packet throughput and increases energy consumption. In this paper, we target such scenarios by presenting Low-Power Distributed Queuing (LPDQ), a highly efficient and low-power MAC protocol. LPDQ is able to self-schedule data transmissions, acting as a FSA MAC under light traffic and seamlessly converging to a Time Division Multiple Access (TDMA) MAC under congestion. The paper presents the design principles and the implementation details of LPDQ using low-power commercial radio transceivers. Experiments demonstrate an efficiency close to 99% that is independent of the number of nodes and is fair in terms of resource allocation.Peer ReviewedPostprint (author’s final draft
Millimeter Wave Ad Hoc Networks: Noise-limited or Interference-limited?
In millimeter wave (mmWave) communication systems, narrow beam operations
overcome severe channel attenuations, reduce multiuser interference, and thus
introduce the new concept of noise-limited mmWave wireless networks. The regime
of the network, whether noise-limited or interference-limited, heavily reflects
on the medium access control (MAC) layer throughput and on proper resource
allocation and interference management strategies. Yet, alternating presence of
these regimes and, more importantly, their dependence on the mmWave design
parameters are ignored in the current approaches to mmWave MAC layer design,
with the potential disastrous consequences on the throughput/delay performance.
In this paper, tractable closed-form expressions for collision probability and
MAC layer throughput of mmWave networks, operating under slotted ALOHA and
TDMA, are derived. The new analysis reveals that mmWave networks may exhibit a
non-negligible transitional behavior from a noise-limited regime to an
interference-limited regime, depending on the density of the transmitters,
density and size of obstacles, transmission probability, beamwidth, and
transmit power. It is concluded that a new framework of adaptive hybrid
resource allocation procedure, containing a proactive contention-based phase
followed by a reactive contention-free one with dynamic phase durations, is
necessary to cope with such transitional behavior.Comment: accepted in IEEE GLOBECOM'1
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
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
Cross Layer Aware Adaptive MAC based on Knowledge Based Reasoning for Cognitive Radio Computer Networks
In this paper we are proposing a new concept in MAC layer protocol design for
Cognitive radio by combining information held by physical layer and MAC layer
with analytical engine based on knowledge based reasoning approach. In the
proposed system a cross layer information regarding signal to interference and
noise ratio (SINR) and received power are analyzed with help of knowledge based
reasoning system to determine minimum power to transmit and size of contention
window, to minimize backoff, collision, save power and drop packets. The
performance analysis of the proposed protocol indicates improvement in power
saving, lowering backoff and significant decrease in number of drop packets.
The simulation environment was implement using OMNET++ discrete simulation tool
with Mobilty framework and MiXiM simulation library.Comment: 8 page
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