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40
On neighbor discovery in wireless networks with directional antennas
- In IEEE INFOCOM
, 2005
"... Neighbor discovery is one of the first steps in the initializa-tion of a wireless ad hoc network. In this paper, we design and analyze practical algorithms for neighbor discovery in wireless networks. We first consider an ALOHA-like neigh-bor discovery algorithm in a synchronous system, proposed in ..."
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Cited by 111 (4 self)
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Neighbor discovery is one of the first steps in the initializa-tion of a wireless ad hoc network. In this paper, we design and analyze practical algorithms for neighbor discovery in wireless networks. We first consider an ALOHA-like neigh-bor discovery algorithm in a synchronous system, proposed in an earlier work. When nodes do not have a collision de-tection mechanism, we show that this algorithm reduces to the classical Coupon Collector’s Problem. Consequently, we show that each node discovers all its n neighbors in an ex-pected time equal to ne(lnn+c), for some constant c. When nodes have a collision detection mechanism, we propose an algorithm based on receiver status feedback which yields a lnn improvement over the ALOHA-like algorithm. Our algorithms do not require nodes to have any estimate of the number of neighbors. In particular, we show that not knowing n results in no more than a factor of two slow-down in the algorithm performance. In the absence of node synchronization, we develop asynchronous neighbor discov-ery algorithms that are only a factor of two slower than their synchronous counterparts. We show that our algorithms can achieve neighbor discovery despite allowing nodes to begin execution at different time instants. Furthermore, our al-gorithms allow each node to detect when to terminate the neighbor discovery phase.
Revisiting Neighbor Discovery with Interferences Consideration
- in Proceedings of the 3rd ACM International Workshop on Performance Evaluation of Wireless Ad Hoc, Sensor and Ubiquitous Networks
, 2006
"... In wireless multi-hop networks, hello protocols for neighbor discovery are a basic service offered by the networking stack. However, their study usually rely on rather simplistic models which do not take into account problems resulting from low level layers, such as the physical layer. One of the pe ..."
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Cited by 17 (2 self)
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In wireless multi-hop networks, hello protocols for neighbor discovery are a basic service offered by the networking stack. However, their study usually rely on rather simplistic models which do not take into account problems resulting from low level layers, such as the physical layer. One of the peculiarities of radio communications is the presence of interferences which decrease the capacity of the medium. In this paper, we consider a random hello protocol inspired by aloha and we study the impact of the interferences on the neighbor discovery process. As expected, we prove that, in average and in the presence of interferences, a node discovers only a subset of its neighbors. We propose then an analytical model to compute the average number of nodes that a given node may expect to discover in its neighborhood. Finally, we present a hello protocol with sleep periods. We show how to optimize this protocol using our hybrid model. A real scenario stemming from the CAPNET project is then analyzed and studied.
1 Interference analysis for highly directional 60 GHz mesh networks: the case for rethinking medium
, 2010
"... access control ..."
1 Blockage and Directivity in 60 GHz Wireless Personal Area Networks: From Cross-Layer Model to Multihop MAC
"... Abstract—We present a cross-layer modeling and design approach for multiGigabit indoor wireless personal area networks (WPANs) utilizing the unlicensed millimeter (mm) wave spectrum in the 60 GHz band. Our approach accounts for the following two characteristics that sharply distinguish mm wave netwo ..."
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Cited by 12 (1 self)
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Abstract—We present a cross-layer modeling and design approach for multiGigabit indoor wireless personal area networks (WPANs) utilizing the unlicensed millimeter (mm) wave spectrum in the 60 GHz band. Our approach accounts for the following two characteristics that sharply distinguish mm wave networking from that at lower carrier frequencies. First, mm wave links are inherently directional: directivity is required to overcome the higher path loss at smaller wavelengths, and it is feasible with compact, low-cost circuit board antenna arrays. Second, indoor mm wave links are highly susceptible to blockage because of the limited ability to diffract around obstacles such as the human body and furniture. We develop a diffraction-based model to determine network link connectivity as a function of the locations of stationary and moving obstacles. For a centralized WPAN controlled by an access point, it is shown that multihop communication, with the introduction of a small number of relay nodes, is effective in maintaining network connectivity in scenarios where single-hop communication would suffer unacceptable outages. The proposed multihop MAC protocol accounts for the fact that every link in the WPAN is highly directional, and is shown, using packet level simulations, to maintain high network utilization with low overhead. Index Terms—Wireless personal area networks (WPAN), Millimeter wave WPANs, Millimeter wave propagation, 60 GHz networks, Medium Access Control (MAC). I.
A distributed asynchronous directionalto-directional MAC protocol for wireless ad hoc networks
- IEEE Trans. Veh. Tech
, 2009
"... Abstract—The use of directional antennas in ad hoc networks has received growing attention because of its high spatial reuse and high antenna gains. The medium access control (MAC) protocol design with directional antennas is nontrivial due to the deafness and collision problems. The existing protoc ..."
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Cited by 9 (1 self)
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Abstract—The use of directional antennas in ad hoc networks has received growing attention because of its high spatial reuse and high antenna gains. The medium access control (MAC) protocol design with directional antennas is nontrivial due to the deafness and collision problems. The existing protocols assumed that the nodes can operate in both directional and omnidirectional modes. However, using both modes leads to the asymmetry-in-gain prob-lem. In this paper, we propose a directional-to-directional (DtD) MAC protocol, where both senders and receivers operate in a directional-only mode. We also derive the saturation throughput of ad hoc networks using DtD MAC. The analytical and simulation results show that DtD MAC can significantly improve the through-put and maintain good fairness among competing flows. We further evaluate the DtD MAC with millimeter-wave (mmWave) communication technologies, which rely on a directional antenna to perform well and can achieve gigabit data rates. The results obtained are exciting and show that DtD MAC is a promising candidate for mmWave ad hoc networks. Index Terms—Ad hoc networks, directional antennas, medium access control (MAC) protocols, millimeter wave (mmWave). I.
Directional Neighbor Discovery in 60 GHz Indoor Wireless Networks
"... The unlicensed 60 GHz band brings the promise of multi-gigabit data rates to support new applications such as high definition video over wireless links. Signal propagation in the 60 GHz band significantly differs from that in the traditionally used 2.4 and 5 GHz bands. The propagation and penetratio ..."
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Cited by 7 (0 self)
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The unlicensed 60 GHz band brings the promise of multi-gigabit data rates to support new applications such as high definition video over wireless links. Signal propagation in the 60 GHz band significantly differs from that in the traditionally used 2.4 and 5 GHz bands. The propagation and penetration losses in the 60 GHz band are much higher. Furthermore, the signals are often reflected in indoor settings. Previous physical layer studies show that the use of directional antennas can significantly help in coping with these effects. In this paper, we address the problem of neighbor discovery in the 60 GHz band. We account for not only discovery via direct line-of-sight paths, but also via reflected beams. To the best of our knowledge, none of the previous efforts on higher layer protocols for use with directional antennas account for reflections. We consider two approaches for neighbor discovery (a) direct discovery
A directional-to-directional mac protocol for ad-hoc networks
, 2008
"... Abstract — The use of directional antennae in ad hoc networks has received growing attention in recent years. However, most existing directional MAC protocols assume interchangeable di-rectional and omnidirectional modes of operation. Such operation reduces the spatial gain and introduces the asymme ..."
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Cited by 3 (1 self)
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Abstract — The use of directional antennae in ad hoc networks has received growing attention in recent years. However, most existing directional MAC protocols assume interchangeable di-rectional and omnidirectional modes of operation. Such operation reduces the spatial gain and introduces the asymmetry-in-gain problem. In this paper, we propose a directional-to-directional (DtD) MAC protocol for ad-hoc networks that operates in the directional mode exclusively. The protocol is fully distributed, does not require any synchronization, eliminates the asymmetry-in-gain problem, and alleviates the deafness problem. To study the performance of the proposed DtD MAC, we develop an analytical model that estimates the saturation throughput as a function of the number of antenna sectors, packet size and number of contending nodes. The analytical results are validated by extensive simulations with the QualNet simulator. We show that the DtD MAC protocol is practical to take the advantage of directional antennae to improve network throughput and achieve better fairness in ad-hoc networks. I.
Many-to-Many Communication for Mobile Ad Hoc Networks
, 2007
"... We introduce a collaboration-driven approach to the sharing of the available bandwidth in wireless ad hoc networks, which we call many-to-many communication, that allows concurrent multi-packet transmissions (MPTs) and multi-packet receptions (MPRs). Many-to-many communication also permits one-time ..."
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Cited by 3 (0 self)
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We introduce a collaboration-driven approach to the sharing of the available bandwidth in wireless ad hoc networks, which we call many-to-many communication, that allows concurrent multi-packet transmissions (MPTs) and multi-packet receptions (MPRs). Many-to-many communication also permits one-time multi-copy relaying of the same packet, which reduces the packet delivery delay compared to single-copy relaying without any penalty in capacity. Our scheme is based on the integration of multi-user detection and position-location information with frequency and code division in mobile ad hoc networks (MANETs). Transmissions are divided in frequency and codes according to node locations, and successive interference cancellation (SIC) is used at receivers to allow them to decode and use all transmissions from strong interfering sources. Consequently, the interference is divided into constructive interference (COI) and destructive interference (DEI). We show that, if each node is allowed to expand its bandwidth, both the link’s Shannon capacity and the per source-destination throughput scale like O(n α 2) (upper-bound) and Ω[f(n)] (lower-bound), for n nodes in the network, a path loss parameter α> 2, and 1≤f(n)<n α
An Integrated Scheme for Fully-Directional Neighbor Discovery and Topology
- Management in Mobile Ad hoc Networks,” in MASS
, 2006
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Exploiting Diversity Gain in MIMO Equipped Ad hoc Networks
"... Abstract—MIMO links coupled with space-time codes can combat fading and hence can significantly increase the capacity of ad hoc networks. This ability of providing “ diversity gain ” can increase the capacity of ad hoc networks. Currently, most of the studies on MIMO links systems are focused on the ..."
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Cited by 3 (1 self)
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Abstract—MIMO links coupled with space-time codes can combat fading and hence can significantly increase the capacity of ad hoc networks. This ability of providing “ diversity gain ” can increase the capacity of ad hoc networks. Currently, most of the studies on MIMO links systems are focused on the physical layer without taking into consideration the intricacies of a network-wide deployment. In this work we study the benefits of a network-wide deployment of MIMO links in mobile ad hoc networks. In particular, we examine the trade-offs between using the possible diversity gain for an increase in range or an increase in rate. We make minor modifications to traditionally used MAC and routing schemes popularly considered for ad hoc networks and perform extensive simulations to understand the above trade-offs. We quantify the performance trade-offs in terms of the achieved throughput and end-to-end latency. Our studies can serve as a precursor to the design of adaptive schemes that can exploit the achievable diversity to increase range/rate depending on the scenario at hand. I.
