Wireless communication between sensors allows the formation of flexible sensor networks, which can be deployed rapidly over wide or inaccessible areas However, the need to gather data from all sensors in the network imposes constraints on the distances between sensors This survey describes the state of the art in techniques for determining the minimum density and optimal locations of relay nodes and ordinary sensors to ensure connectivity, subject to various degrees of uncertainty in the locations of the nodes

https://www.mdpi.com/1424-8220/9/10/7664/pdf

Connectivity, coverage and placement in wireless sensor networks.

Broadcast or flooding is a dissemination technique of paramount importance in wireless ad hoc networks. The broadcast scheme is widely used within routing protocols by a wide range of wireless ad hoc networks such as mobile ad hoc networks, vehicular ad hoc networks, and wireless sensor networks, and used to spread emergency messages in critical scenarios after a disaster scenario and/or an accidents. As the type broadcast scheme used plays an important role in the performance of the network, it has to be selected carefully. Though several types of broadcast schemes have been proposed, probabilistic broadcast schemes have been demonstrated to be suitable schemes for wireless ad hoc networks due to a range of benefits offered by them such as low overhead, balanced energy consumption, and robustness against failures and mobility of nodes. In the last decade, many probabilistic broadcast schemes have been proposed by researchers. In addition to reviewing the main features of the probabilistic schemes found in the literature, we also present a classification of the probabilistic schemes, an exhaustive review of the evaluation methodology including their performance metrics, types of network simulators, their comparisons, and present some examples of real implementations, in this paper.

/pdf/a-survey-on-probabilistic-broadcast-schemes-for-wireless-ad-7b3rmky4fl.pdf

A survey on probabilistic broadcast schemes for wireless ad hoc networks

A comparative study of scenario-driven multi-hop broadcast protocols for VANETs

Wireless Community Networks (WCNs) are created and managed by a local community with the goal of sharing Internet connection and offering local services. This paper analyses the data collected on three large WCNs, ranging from 131 to 226 nodes, and used daily by thousands of people. We first analyse the topologies to get insights in the fundamental properties, next we concentrate on two crucial aspects: (i) the routing layer and (ii) metrics on the centrality of nodes and the network robustness. All the networks use the Optimized Link State Routing (OLSR) protocol extended with the Expected Transmission Count (ETX) metric. We analyse the quality of the routes and two different techniques to select the Multi-Point Relay (MPR) nodes. The centrality and robustness analysis shows that, in spite of being fully decentralized networks, an adversary that can control a small fraction of carefully chosen nodes can intercept up to 90% of the traffic. The collected data-sets are available as Open Data, so that they can be easily accessed by any interested researcher, and new studies on different topics can be performed. In fact, WCN are just an example of large wireless mesh networks, so our methodology can be applied to any other large mesh network, including commercial ISP networks.

/pdf/a-week-in-the-life-of-three-large-wireless-community-4byy9v8cth.pdf

A week in the life of three large Wireless Community Networks

Design of a multi-hop dynamic consensus algorithm over wireless sensor networks

Almost every routing protocol in mobile ad hoc networks (MANETs) depends on a broadcast scheme to disseminate routing information. For this reason, creating an efficient broadcast scheme is important and a large variety of approaches have been proposed. Among them, multipoint relay (MPR) is one of the distributed broadcast schemes which is efficient and simple. Based on the MPR concept, many broadcast schemes have been proposed, which generally focus on different performance issues. In this article we present a comprehensive survey of MPR-based broadcast schemes, classified into three categories based on their objectives. Different heuristics are described, and the evaluation of their performances is provided in light of their costs. Advantages and limitations of different broadcast schemes are also highlighted.

A survey of multipoint relay based broadcast schemes in wireless ad hoc networks

Flooding methods have been widely used by routing protocols to disseminate route information and control messages in wireless ad hoc and sensor networks both. However, most of the efficient flooding approaches proposed in the research literature are designed for ad hoc networks only, and they might not be suitable for wireless sensor networks due to their higher node densities, constrained energy and memory resources in sensor nodes. In this paper, we present a distributed low-cost flooding algorithm that is designed particularly for wireless sensor networks. We prove that our new algorithm has O(n + Delta) time and O(n) signaling message complexity, where n is the total number of nodes in a network and Delta is the maximum node degree. Moreover, we show that our low-cost algorithm has a constant approximation ratio, and its signaling message size is also bounded by a constant. Our simulation study demonstrates that our new algorithm not only generates fewer forwarding nodes, but it also uses much less number of signaling messages and has significantly smaller signaling message size than other algorithms published in the literature.

A Low-Cost Flooding Algorithm for Wireless Sensor Networks

Resource reservation protocol (RSVP) is a network-control protocol used to guarantee Quality-of-Service (QoS) requirements for real-time applications such as Voice-over-IP (VoIP) or Video-over-IP (VIP). However, RSVP was designed for end-systems whose IP addresses do not change. Once mobility of an end-system is allowed, the dynamically changing mobile IP address inevitably impacts on RSVP performance. Our study aims to first quantify the significance of this impact, and then propose a modified RSVP mechanism that provides improved performance during handoffs. Our simulations reveal that the deployment of standard RSVP over Mobile IPv6 (MIPv6) does not yield a satisfactory result, particularly in the case of VIP traffic. Fast Handovers for Mobile IPv6 (FMIPv6) was found to be providing the best performance in all tested scenarios, followed by Hierarchical Mobile IPv6 (HMIPv6) with a single exception: during low handoff rates with VoIP traffic, MIPv6 outperformed HMIPv6. We then designed a new RSVP mechanism, and tested it against standard RSVP. We found that the proposed approach provides a significant improvement of 54.1% in the Total Interruption in QoS (TIQoS) when deployed over a MIPv6 wireless network. For HMIPv6, performance depended primarily on the number of hierarchical levels in the network, with no improvement in TIQoS for single-level hierarchy and up to 37% for a 5-level hierarchy. FMIPv6 on the other hand, provided no room for improvement due to pre-handoff signaling and the tunneling mechanism used to ensure a mobile node (MN)'s connectivity during a handoff, regardless of the RSVP mechanism used. Copyright © 2007 John Wiley & Sons, Ltd.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/wcm.560

Mobility protocols and RSVP performance in wireless IPv6 networks: shortcomings and solutions

RSVP is considered the Integrated Services (IntServ) standard in providing QoS guarantees while Mobile IP is the standardized IETF proposal to facilitate terminal mobility in wireless IP networks. Since the former provides QoS guarantees and the later offers IP mobility, one would think that simply superimposing the two technologies would yield an optimum solution. This however is evidently not the case since RSVP was initially designed with static nodes in mind. This paper attempts to highlight the key issues involved with such an interaction by providing a testbed to quantitatively analyse how RSVP and MIPv6 hosts would likely to interact under different congestion scenarios. This paper also evaluates the potential effects and/or advantages of applying Mobile IPv6 enhancements such as Hierarchical Mobile IPv6 and Fast Handovers. As speculated, simply deploying default RSVP over MIPv6 does not yield an optimum result. More importantly, we show that in high congestion scenarios the IP-in-IP encapsulation introduced by HMIPv6 creates additional end-to-end packet delay and a slightly higher packet loss than MIPv6; thereby degrading the Mean Opinion Score (MOS). Based on our findings, MIPv6 with Fast Handovers (FMIPv6) operates best with RSVP due to minimal loss of packets during handoffs in addition to a smaller IP header when compared to HMIPv6. Finally we summarise the basic requirements needed to achieve an optimum QoS solution

Interaction of RSVP and Mobile IPv6 Protocols: An Evaluation of Performance on Wireless Networks

Mobile IP is the standardized IETF proposal to facilitate terminal mobility in wireless IP networks while RSVP is considered the integrated services standard in providing QoS guarantees. Since the former offers IP mobility and the later provides QoS guarantees, one would think that simply superimposing the two technologies would yield an optimum solution. This however is evidently not the case since RSVP was initially designed with static nodes in mind. A key issue relates to the IP-in-IP encapsulation of packets. This conceals the identity of RSVP packets from intermediate routers which fail to recognize them, thereby not reserving the necessary resources. Another issue arises in the event of a handoff where the interruption in QoS causes a notable degradation in application level performance. To address these issues, we propose a mobility extension which is fully compatible with RFC2205, and can therefore be implemented with minimal changes to end nodes. We assess our proposal by evaluating VoIP performance using parametric simulations. Our results indicate 27.9% improvement in QoS interruption when using mobile IP, and 12.5% with hierarchical mobile IP.

Nallasamy Mani

Papers

A survey of multipoint relay based broadcast schemes in wireless ad hoc networks

A Low-Cost Flooding Algorithm for Wireless Sensor Networks

Mobility protocols and RSVP performance in wireless IPv6 networks: shortcomings and solutions

Interaction of RSVP and Mobile IPv6 Protocols: An Evaluation of Performance on Wireless Networks

WLC40-3: A Mechanism for Enhancing VoIP Performance over Wireless Networks using Embedded Mobility-Specific Information in RSVP Objects