Opportunistic routing in wireless mesh networks

Advances in communication and networking technologies are rapidly making ubiquitous network connectivity a reality. In recent years, Wireless Mesh Networks (WMNs) have already become very popular and been receiving an increasing amount of attention by the research community. Basically, a WMN consists of simple mesh routers and mesh clients, where mesh routers form the backbone of WMN. Due to the limited transmission range of the radio, many pairs of nodes in WMN may not be able to communicate directly, hence they need other intermediate nodes to forward packets for them. Routing in such networks is an important issue and it poses great challenges. Opportunistic Routing (OR) has been investigated in recent years as a way to increase the performance of WMNs by exploiting its broadcast nature. In OR, in contrast to traditional routing, instead of pre-selecting a single specic node to be the next-hop as a forwarder for a packet, an ordered set of nodes (referred to as candidates) is selected as the potential next-hop forwarders. Thus, the source can use multiple potential paths to deliver the packets to the destination. More specically, when the current node transmits a packet, all the candidates that successfully receive it will coordinate with each other to determine which one will actually forward it, while the others will simply discard the packet. This dissertation studies the properties, performance, maximum gain, candidate selection algorithms and multicast delivery issues about Opportunistic Routing in WMNs. Firstly, we focus on the performance analysis of OR by proposing a Discrete Time Markov Chain (DTMC). This model can be used to evaluate OR in terms of expected number of transmissions from the source to the destination. Secondly, we apply our Markov model to compare relevant candidate selection algorithms that have been proposed in the literature. They range from non-optimum, but simple, to optimum, but with a high computational cost. Thirdly, the set of candidates which a node uses and priority order of them have a signicant impact on the performance of OR. Therefore, using a good metric and algorithm to select and order the candidates are key factors in designing an OR protocol. As the next contribution we propose a new metric that measures the expected distance progress of sending a packet using a set of candidates. Based on this metric we propose a candidate selection algorithm which its performance is very close to the optimum algorithm although our algorithm runs much faster. Fourthly, we have investigated the maximum gain that can be obtained using OR. We have obtained some equations that yield the distances of the candidates in OR such that the per transmission progress towards the destination is maximized. Based on these equations we have proposed a novel candidate selection algorithm. Our new algorithm only needs the geographical location of nodes. The performance of our proposal is very close to the optimum candidate selection algorithm although our algorithm runs much faster. Finally, using OR to support multicast is an other issue that we have investigated in this thesis. We do so by proposing a new multicast protocol which uses OR. Unlike traditional multicast protocols, there is no designated next-hop forwarder for each destination in our protocol, thus the delivery ratio is maximized by taking advantage of spatial diversity

Candidate Selection Algorithms in Opportunistic Routing based on Distance Progress

Opportunistic Routing (OR) is a new class of routing protocols that selects the next-hop forwarder on-the-fly. In contrast to traditionally routing, OR does not select a single node as the next-hop forwarder, but a set of forwarder candidates. When a packet is transmitted, the candidates coordinate such that the best one receiving the packet will forward it, while the others will discard the packet. The selection and prioritization of candidates, referred to as candidate selection algorithm, has a great impact on OR performance. In this paper we propose and study two new candidate selection algorithms based on the geographic position of nodes. This information is used by the candidate selection algorithms in order to maximize the distance progress towards the destination. We compare our proposals with other well-known candidate selection algorithms proposed in the literature through mathematical analysis and simulation. We show that candidate selection algorithms based on distance progress achieve almost the same performance as the optimum algorithms proposed in the literature, while the computational cost is dramatically reduced.Darehshoorzadeh, A.; Cerdà-Alabern, L.; Pla, V. (2015). Candidate Selection Algorithms in Opportunistic Routing based on Distance Progress. International Journal of Ad Hoc and Ubiquitous Computing. 20(3):137-147. doi:10.1504/IJAHUC.2015.073168S13714720

Modeling and comparison of candidate selection algorithms in opportunistic routing

Opportunistic Routing (OR) has been investigated in recent years as a way to increase the performance of multihop wireless networks by exploiting its broadcast nature. In contrast to traditional routing, where traffic is sent along pre-determined paths, in OR an ordered set of candidates is selected for each next-hop. Upon each transmission, the candidates coordinate such that the most priority one receiving the packet actually forwards it. Most of the research in OR has been addressed to investigate candidate selection algorithms. In this paper we propose a discrete time Markov chain to assess the improvement that may be achieved using opportunistic routing. We use our model to compare a selected group of candidate selection algorithms that have been proposed in the literature. Our main conclusion is that optimality is obtained at a high computational cost, with a performance gain very similar to that of much simpler but non-optimal algorithms. Therefore, we conclude that fast and simple OR candidate selection algorithms may be preferable in dynamic networks, where the candidates sets are likely to be updated frequently. © 2011 Elsevier B.V. All rights reserved.This work was supported by the Spanish government through projects TIN2010-21378-C02-01 and TIN2010-21378-C02-02, by the Generalitat de Catalunya through project 2009-SGR-1167, and by the European Commission through the NoE EuroNF.Darehshoorzadeh, A.; Cerdà-Alabern, L.; Pla, V. (2011). Modeling and comparison of candidate selection algorithms in opportunistic routing. Computer Networks. 55(13):2886-2898. https://doi.org/10.1016/j.comnet.2011.06.009S28862898551

Optimum Node Placement in Wireless Opportunistic Routing Networks

In recent years there has been a growing interest in opportunistic routing as a way to increase the capacity of wireless networks by exploiting its broadcast nature. In contrast to traditional uni-path routing, in opportunistic routing the nodes overhearing neighbor¿s transmissions can become candidates to forward the packets towards the destination. In this paper we address the question: What is the maximum performance that can be obtained using opportunistic routing? To answer this question we use an analytical model that allows to compute the optimal position of the nodes, such that the progress towards the destination is maximized. We use this model to compute bounds to the minimum expected number of transmissions that can be achieved in a network using opportunistic routing.This work was supported by the Spanish Ministerio de Ciencia e Innovacion through the Projects TIN2010-21378-C02-01 and TIN2010-21378-C02-02 and by the Generalitat de Catalunya through Project 2009-SGR-1167.Cerdá Alabern, L.; Darehshoorzadeh, A.; Pla, V. (2013). Optimum Node Placement in Wireless Opportunistic Routing Networks. Ad Hoc Networks. 11(8):2273-2287. https://doi.org/10.1016/j.adhoc.2013.05.010S2273228711

Distance progress based opportunistic routing for wireless mesh networks

Opportunistic Routing (OR) has been proposed to improve the performance of multihop wireless networks by exploiting its broadcast nature. In contrast to traditional routing, where traffic is sent along pre-determined paths, in OR an ordered set of candidates is selected as the next-hop potential forwarders. The candidate selection is a key issue in OR and many algorithms have been proposed in the literature. In this paper, we define a new metric for candidate selection based on the expected distance progress of sending a packet under OR. By using this metric we propose a hop-by-hop candidate selection and prioritization algorithm that we call Distance Progress Based Opportunistic Routing , DPOR. In contrast to other algorithms, in DPOR each node selects its candidates set independently, without considering the other nodes’ candidates sets. DPOR only relies on the neighbors’ geographic position of forwarder and the links delivery probability between forwarder and its neighbors. We compare our proposal with four other relevant candidate selection algorithms. Our results show that DPOR performance is almost the same as optimum candidate selection algorithm, while DPOR requires less information and run much fasterPeer Reviewe

Selected topics in opportunistic routing in wireless networks

Oportunistic Routing (OR) has been investigated in recent years as a way to increase the performance of Wireless Mesh Networks. In OR, in contrast to traditional routing, instead of pre-selecting a single specific node to be the next-hop as a forwarder for a packet, an ordered set of nodes, called candidates, is selected. When the current node transmits a packet, all the candidates that successfully receive it will coordinate with each other to determine which one will actually forward it, while the others will simply discard the packet. This book is a research approach to OR. Analytic models and simulation are used to investigate main issues in OR. These include practical ones, as the selection of candifates and theoretical ones, as the maximum performance that may be achieved using OR.Postprint (published version

Multicast delivery using opportunistic routing in wireless mesh networks

Opportunistic routing (OR) has been proposed to improve the efficiency of unicast protocols in wireless networks. In OR, an ordered set of nodes is selected as the next-hop potential forwarders. In this paper, we investigate how OR can be used to improve multicast delivery by proposing a new multicast routing protocol based on opportunistic routing for wireless mesh networks, named multicast opportunistic routing protocol (MORP). MORP opportunistically employs a set of forwarders to send a packet toward all destinations. Each forwarder is responsible for sending the packet to a subset of destinations. Based on the candidates that successfully receive the packet in each transmission, MORP builds a tree on-the-fly. We compare our proposal with two well known ODMRP and ADMR multicast protocols. Our results demonstrate that MORP outperforms ODMRP and ADMR, reducing the number of data transmissions and increasing the delivery ratio.Peer Reviewe

A new multicast opportunistic routing protocol for wireless mesh networks

Opportunistic Routing (OR) has been proposed to improve the efficiency of unicast protocols in wireless networks. In contrast to traditional routing, instead of preselecting a single specific node to be the next-hop forwarder, an ordered set of nodes (referred to as candidates) is selected as the next-hop potential forwarders. In this paper, we propose a new multicast routing protocol based on OR for wireless mesh networks, named Multicast OR Protocol (MORP). We compare our proposal with the well known ODMRP Multicast protocol. Our results show that Multicast-OR outperforms ODMRP, reducing the number of transmissions and increasing the packet delivery ratio.Peer Reviewe

Modeling and comparison of candidate selection algorithms in opportunistic routing

Opportunistic Routing (OR) has been investigated in recent years as a way to increase the performance of multihop wireless networks by exploiting its broadcast nature. In contrast to traditional routing, where traffic is sent along pre-determined paths, in OR an ordered set of candidates is selected for each next-hop. Upon each transmission, the candidates coordinate such that the most priority one receiving the packet actually forward it. Most of the research in OR has been ddressed to investigate candidate selection algorithms. In this paper we compare a selected group of algorithms that have been proposed in the literature. Our main conclusion is that optimality is obtained at a high computational cost, with a performance gain very similar to that of much simpler but non optimal algorithms. Therefore, we conclude that fast and simple OR candidate selection algorithms may be preferable in dynamic networks, where the candidate sets are likely to be updated frequently.Peer Reviewe

Selected topics in opportunistic routing in wireless networks

Oportunistic Routing (OR) has been investigated in recent years as a way to increase the performance of Wireless Mesh Networks. In OR, in contrast to traditional routing, instead of pre-selecting a single specific node to be the next-hop as a forwarder for a packet, an ordered set of nodes, called candidates, is selected. When the current node transmits a packet, all the candidates that successfully receive it will coordinate with each other to determine which one will actually forward it, while the others will simply discard the packet. This book is a research approach to OR. Analytic models and simulation are used to investigate main issues in OR. These include practical ones, as the selection of candifates and theoretical ones, as the maximum performance that may be achieved using OR