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Identifying Design Requirements for Wireless Routing Link Metrics
Abstract
In this paper, we identify and analyze the requirements to design a new
routing link metric for wireless multihop networks. Considering these
requirements, when a link metric is proposed, then both the design and
implementation of the link metric with a routing protocol become easy.
Secondly, the underlying network issues can easily be tackled. Thirdly, an
appreciable performance of the network is guaranteed. Along with the existing
implementation of three link metrics Expected Transmission Count (ETX), Minimum
Delay (MD), and Minimum Loss (ML), we implement inverse ETX; invETX with
Optimized Link State Routing (OLSR) using NS-2.34. The simulation results show
that how the computational burden of a metric degrades the performance of the
respective protocol and how a metric has to trade-off between different
performance parameters.
... This issue is especially challenging as these networks are built to work in specific scenarios. For example, a monitoring network can require a reasonable level of Packet Delivery Ratio (PDR) [8,9]. On the other hand, when the goal is to enable a VoIP (Voice over Internet Protocol) content, the network needs to keep under control the Endto-End Delay (E2ED) [8,9]. ...
... For example, a monitoring network can require a reasonable level of Packet Delivery Ratio (PDR) [8,9]. On the other hand, when the goal is to enable a VoIP (Voice over Internet Protocol) content, the network needs to keep under control the Endto-End Delay (E2ED) [8,9]. Therefore, distinct applications can demand different Quality of Service (QoS) guarantees [6,[10][11][12]. ...
... In this light, the routing protocols should also consider the different applications can have conflicting quality requirements. As a result, future routing mechanisms must support two or more QoS requirements and take into account the trade-off between them, since state-of-the-art protocols do not have these features natively [9,13]. ...
Ad hoc wireless networks have aroused much interest of the scientific community in the last two decades. The provision of Quality of Service (QoS) is a prominent challenge in this research field, since these networks are prone to suffer from instabilities related to wireless medium and mobility. Depending on application, the protocol needs to consider two or more QoS criteria when solving the routing problem. In this context, this work proposes a multicriteria and adaptive framework for proactive routing in order to generate promising compromise solutions by considering critical network quality indicators. Two new methods are proposed—one based on weighted sum method and another based on compromise method (\(\varepsilon\)-constraint)—and compared with the standard weighted sum method. Aiming to map a single final solution, a utility function is proposed to support the definition of the parameters (weights and constraints) of each method. The results show the framework, jointly with the proposed methods, were efficient in promoting significant improvements in the quality indicators investigated in static and mobile scenarios.
... For example, a metric may/can produce computational overhead and it may also pay cost in terms of other performance metric(s) like achieving minimized end-to-end delay at the cost lower throughput or higher routing overhead. Thus, we analyze/investigate almost all possible design requirements given in [7]. In this paper, we present a mathematical framework for a proposed quality link metric; Bandwidth adjusted Inverse ETX (BIETX). ...
... d exp firstly detects and then handles asymmetry by incorporating loss ratios in forward and reverse directions. Computation of d exp , by taking the product of delivery ratios same as in [7] and [12] leads to avoidance of computational overhead that is generated due to ETX which firstly calculates inverse of all expected delivery ratios and then adds them up. There are two techniques to measure L cap i.e., packet-pair with different size and back-to-back probes with equal size. ...
... From [7], we conclude that routing load is an important issue in SWMhNs and this issue becomes critical whenever the network load increases with increase in either the number of packets or the number of nodes. In OLSR, shortest interval has been used for exchanging topological information in comparison to Destination Sequence Distance Vector (DSDV) and Fish-eye State Routing (FSR) [14] i.e., IntraScopeInterval in FSR and 'full-dump-period' in DSDV are equal to 15s, and, T C IN T ERV AL = 5s in OLSR, resulting in the generation of more routing overhead. ...
In this work, we propose a novel quality link metric; Bandwidth adjusted Inverse ETX (BIETX) for Static Wireless Multi-hop Networks (SWMhNs). The proposed metric considers two path selection parameters into account i.e., packet delivery ratio and link capacity. For computing packet delivery ratios in BIETX, the mechanism of Expected Transmission Count (ETX) is adopted. On the other hand, we take two methods of computing link capacity in BIETX. These methods are based upon the size of pair probes; equal size and different size. We also enhance Optimized Link State Routing (OLSR) protocol while using BIETX. A comparative analysis of proposed metric with equal size and different size pair probe; BIETX-1 and BIETX-2, with two existing quality metrics (ETX and Expected Transmission Time (ETT)) in SWMhNs is also a part of this work. From simulation results, we conclude that BIETX-2 outperforms rest of the metrics because of low routing load in ad-hoc probes, and low routing latencies due to enhancements of routing update frequencies and window size in OLSR.
... An efficiently designed QLM better helps a routing protocol to achieve appreciable performance by dealing with these issues. In our previous work [1], design requirements of QLM are discussed in detail. Moreover, a new QLM, Inverse Expected Transmission Count (InvETX), is also compared with Expected Transmission Count (ETX) [2], Minimum Loss (ML) [3], and Minimum Delay (MD) [4] in Optimized Link State Routing (OLSR) [5] protocol. ...
... achieving high packet delivery ratio on the cost of increased end-to-end delay). Therefore, we analyze almost all possible design requirements in [1]. Further, in our previous work, we implement three existing link metrics, ETX, MD,and ML, and one newly proposed metric, InvETX OLSR, using NS-2.34. ...
... The maximum reachability of a node belonging to Minimizing Longer path increases routing (1) By minimizing the number of transmi- Hop count [14] path length latency and reduces throughssions and (2) path selection with miniput of a path mum loss rates or higher probabilities of successful transmissions, etc. Balancing traffic Overloaded traffic causes drop Divert traffic from congested path or Transmission load rate due to congestion overloaded nodes to underloaded or reduction [15] idle ones Minimizing delay Delay results time-out buffer Delay can be reduced with selection ETX [15], [14], per of a path having minimum intraflow hop RTT, [11] per and interflow interferences along with hop PktPair [11] queuing delays and maximum link capacity ML [3] Maximizing networks capacity directly effects (1) Minimize interferences or retransmissions, MIC [14] aggregating throughput and (2) allow the multiple bandwidth rates to coexist in a network where a higher channel rate is used over each link Minimizing energy A path with an unreliable Reduction in retransmissions during MTPR [17], consumption link produces longer delay due routing to optimize communication delay MBCR [18] to higher retransmission rates and ultimately results in an increase in energy consumption Minimizing channel/ Data flow switching on different Interface assignment strategy keeps MIC [14], interface switching channels results in delay one interface fixed on a specific channel, WCETT [14] while other interfaces can be switched among the remaining channels; when necessary, Minimizing the Computational overhead consumes computations should be considered InvETX [1] computational memory, processing capability, that must not consume memory, processing overhead and battery power capability, and, most importantly, battery power Minimizing Intraflow and interflow interferences During path calculation, capture diversity MCR protocol interference result in bandwidth starvation of channel assignments and link capacity [14] and [14] Maximizing Instability in path weight results Load sensitivity or topology- Link affinity metric [19] route stability in drop rates dependent metrics solve instability issues with MCMR [20] Maximizing Faulty routes cause drop rates This problem can be solved through wireless ad hoc fault tolerance/ in high network flows providing redundant information of network [21] minimizing route alternative paths sensitivity Avoiding short-and Redundant links due to short- (1) Minimum TTL value that eliminates OLSR in long-lived and long-lived loops resulted in mini-loops [16]; (2) fresh sequence sparse WMNs [16] loops more path lengths and consequently number, etc. quently increased E2ED Considering E2ED in static networks cause A suitable trade-off helps to increase ML [3] performance drop rate efficiency trade-offs Also, the MPR(u) set of a node (u), a subset of H 1 (u), can be defined as follows: ...
In this paper, we propose a new Quality Link Metric (QLM), “Inverse Expected Transmission Count
(InvETX),” in Optimized Link State Routing (OLSR) protocol. Then, we compare performance of three existing
QLMs which are based on loss probability measurements: Expected Transmission Count (ETX), Minimum Delay (MD), and Minimum Loss (ML) in Static Wireless Multihop Networks (SWMhNs). A novel contribution of this paper is enhancement in conventional OLSR to achieve high efficiency in terms of optimized routing load and routing latency. For this purpose, first we present a mathematical framework, and then to validate this frame work, we select three performance parameters to simulate default and enhanced versions of OLSR. The three chosen performance parameters are throughput, Normalized Routing Load, and End-to-End Delay. From the simulation results, we conclude that adjusting the frequencies of topological information exchange results in high efficiency.
... An efficiently designed QLM better helps a routing protocol to achieve appreciable performance by dealing with these issues. In our previous work[1], design requirements of QLM are discussed in detail. Moreover, a new QLM; InvETX, is also compared with Expected Transmission Count (ETX)[2], Minimum Loss (ML) and Minimum Delay (MD)[4]in Optimized Link State Routing (OLSR)[5]protocol. ...
... For example, a routing protocol achieves higher throughput at the cost of end-to-end delay or routing overhead. Therefore, we analyze possible design requirements in[1]. Further, in our previous work, we implement three existing link metrics; ETX, MD,and ML, and one newly proposed metric; InvETX OLSR using NS-2.34. ...
... As a result, InvET X achieves higher throughputs than M L and ET X. Similarly, M L performs better than ET X. From[1], we analyze that routing load is a critical issue in SWMhNs when network load increases either with increase in number of nodes or with increase in number of packets. As, OLSR uses the shortest interval for exchanging topological information as compared to DSDV, i.e., 'full-dump-period' in DSDV, whereas, in OLSR T C IN T ERV AL = 5s, therefore, it causes more routing overhead. ...
In this paper, we propose a new Quality Link Metric (QLM), ``Inverse Expected
Transmission Count (InvETX)'' in Optimized Link State Routing (OLSR) protocol.
Then we compare performance of three existing QLMs which are based on loss
probability measurements; Expected Transmission Count (ETX), Minimum Delay
(MD), Minimum Loss (ML) in Static Wireless Multi-hop Networks (SWMhNs). A novel
contribution of this paper is enhancement in conventional OLSR to achieve high
efficiency in terms of optimized routing load and routing latency. For this
purpose, first we present a mathematical framework, and then to validate this
frame work, we select three performance parameters to simulate default and
enhanced versions of OLSR. Three chosen performance parameters are; throughput,
Normalized Routing Load and End-to-End Delay. From simulation results, we
conclude that adjusting the frequencies of topological information exchange
results in high efficiency.
... Several QLMs have been proposed, like, Expected Transmission Count (ETX)[2], Expected Transmission Time (ETT) [3], Interference and Bandwidth Adjusted ETX (IBETX) [4], Expected Link Performance (ELP) [5], Minimum Loss (ML) [6], Minimum Delay (MD)[7] and Inverse ETX (InvETX) [8]. The metrics, ETX, ML, MD and InvETX have already been implemented [8] with a proactive routing protocol, Optimized Link State Routing (OLSR) [9] using Link State routing technique . ...
... Several QLMs have been proposed, like, Expected Transmission Count (ETX)[2], Expected Transmission Time (ETT) [3], Interference and Bandwidth Adjusted ETX (IBETX) [4], Expected Link Performance (ELP) [5], Minimum Loss (ML) [6], Minimum Delay (MD)[7] and Inverse ETX (InvETX) [8]. The metrics, ETX, ML, MD and InvETX have already been implemented [8] with a proactive routing protocol, Optimized Link State Routing (OLSR) [9] using Link State routing technique . While, ETX, IBETX, and ELP are implemented with Destination Sequenced Distance Vector (DSDV) [10] based on distance vector routing algorithm. ...
... Previouse implementation of QLMs in routing protocols have not considered routing load for performance measurements. We, in our previous work [8] have considered routing load while analyzing the performance of OLSR which is a link state based proactive routing protocol. Now, in the same way, we are evaluating the performance of those link metrics along with ETT in this paper. ...
... Several QLMs have been proposed, like, Expected Transmission Count (ETX)[2], Expected Transmission Time (ETT) [3], Interference and Bandwidth Adjusted ETX (IBETX) [4], Expected Link Performance (ELP) [5], Minimum Loss (ML) [6], Minimum Delay (MD)[7] and Inverse ETX (InvETX) [8]. The metrics, ETX, ML, MD and InvETX have already been implemented [8] with a proactive routing protocol, Optimized Link State Routing (OLSR) [9] using Link State routing technique . ...
... Several QLMs have been proposed, like, Expected Transmission Count (ETX)[2], Expected Transmission Time (ETT) [3], Interference and Bandwidth Adjusted ETX (IBETX) [4], Expected Link Performance (ELP) [5], Minimum Loss (ML) [6], Minimum Delay (MD)[7] and Inverse ETX (InvETX) [8]. The metrics, ETX, ML, MD and InvETX have already been implemented [8] with a proactive routing protocol, Optimized Link State Routing (OLSR) [9] using Link State routing technique . While, ETX, IBETX, and ELP are implemented with Destination Sequenced Distance Vector (DSDV) [10] based on distance vector routing algorithm. ...
... Previouse implementation of QLMs in routing protocols have not considered routing load for performance measurements. We, in our previous work [8] have considered routing load while analyzing the performance of OLSR which is a link state based proactive routing protocol. Now, in the same way, we are evaluating the performance of those link metrics along with ETT in this paper. ...
In this paper, we compare and analyze performance of five quality link
metrics forWireless Multi-hop Networks (WMhNs). The metrics are based on loss
probability measurements; ETX, ETT, InvETX, ML and MD, in a distance vector
routing protocol; DSDV. Among these selected metrics, we have implemented ML,
MD, InvETX and ETT in DSDV which are previously implemented with different
protocols; ML, MD, InvETX are implemented with OLSR, while ETT is implemented
in MR-LQSR. For our comparison, we have selected Throughput, Normalized Routing
Load (NRL) and End-to-End Delay (E2ED) as performance parameters. Finally, we
deduce that InvETX due to low computational burden and link asymmetry
measurement outperforms among all metrics.
... Giving measurable QoS ensures a viable data transfer capacity. Similarly, on observing the patterns on how the Internet has transformed people lives by trading various types of data among countless customers, WSNs may sooner rather than later be similarly emerge to be critical players by providing data about the physical wonders of intrigue and eventually having the option to recognise and control them to develop increasingly precise models of the physical world [8][9][10]. This is due to the fact that WSNs are completely different from traditional systems in this regard. ...
Quality of Service (QoS) in Wireless Sensor Networks (WSN) are contemplated as one on the major attributes in evaluating the overall efficiency of them. Some of the qualities of WSNs include incredibly asset compelled sensors, irregular arrangement of sensors in the scene of deployment, novel information driven correspondence conventions that presents remarkable challenges in the improvement of Quality of Service support in Wireless Sensor Networks. The appropriation of WSN by applications require complex tasks that extends from human services to mechanical checking that are necessary for a wide range of day-to-day and remote applications. WSN has increased a lot of consideration in the present exploration for supporting a wide assortment of utilizations including the interactive media applications. Interactive media applications that are proposed are viewed as delay-sensitive and time-critical applications and require enough vitality and correspondence assets. The proposed QoS-dependent and varied clustered routing (QoS–VCR) algorithm preserves the vitality in the system.
... The authors in [16] identify a diversity of possible requirements to be addressed in a MANET, such as: minimizing hop-count, minimizing delay, maximizing data delivery, minimizing energy consumption, minimizing computational overhead, maximizing route stability, balancing traffic load, among others. The work also relates these requirements to the main link evaluation metrics and points out the associated performance trade-offs. ...
Ad-hoc Wireless Networks provide a major base for ubiquitous computing development. In such networks, the communication occurs by multiple hops in a shared medium. In order to meet the different requirements of the applications, routing solutions aware of Quality of Service (QoS) have been developing. However, single-criterion strategies are unable to cope with conflicting objectives that commonly appear in these networks. This work proposes a multicriteria approach that considers End-to-End Delay (E2ED) and Packet Delivery Probability (PDP) as vital criteria in the route discovery process. For this purpose, Optimized Link State Routing Protocol (OLSR) with a modified Dijkstra algorithm is applied, wherein the bi-objective problem is transformed into a mono-objective problem through the epsilon-constraint technique. Extensive simulations have demonstrated that the multicriteria method can provide efficient routing in mobile environments, and it has outperformed the best results of single-criterion methods in terms of Packet Loss Ratio (PLR) by nearly 5-35 %. The results also have shown the potential of the model in finding a proper trade-off in relation to the number of hops and End-to-End Delay.
... The outcome displays the improved performance as compared to the existing protocol. In future, one can modify this problem statement to implement various link metrics that like ETX link metrics [16,17]. ...
... Because, a link metric provides all available end-to-end paths and the best path information to the respective protocol. So, in future, we are interested to develop a new link metric, like [41] and [42]. ...
Mobile Ad-hoc NETworks (MANETs) are comprised of wireless mobile nodes that are communicating
with each other without any infrastructure. Vehicular Ad-hoc NETwork (VANET) is
a special type of MANETs in which vehicles with high mobility need to communicate with each
other. In our project, a framework for link availability for static as well as dynamic network and
also experimental parameters in which Packet Delivery Ratio (PDR), effect of link duration over
End-to-End Delay (E2ED) and Normalized Routing Overhead (NRO) in terms of control packets
is analyzed and modeled for MANETs and VANETs. Moreover, this project also contributes the
performance comparison of three reactive routing potocols; Ad-hoc On-Demand Distance Vector
(AODV), DYnamic Source Routing (DSR), DYnamic MANET On-Demand (DYMO) and
three proactive protocols; Destination Sequenced Distance Vector (DSDV), Fish-eye State Routing
(FSR) and Optimized Link State Routing (OLSR). A novel contribution of this work is enhancement
of efficiency of these protocols except DSDV. Three performance parameters; PDR, E2ED
and NRO with varying scalabilities are measured to analyze performance of the selected protocols
both with default and enhanced version. From extensive simulations, it is observed that DSR
outperforms both in MANETs and in VANETs at the cost of delay. Moreover, DSR performs better
in VANETs as compared to MANETs. The NS-2 is used for simulation with TwoRayGround
propagation model. The Simulation of Urban MObility (SUMO) and Vehicular Ad-hoc Networks
Mobility Simulator (VanetMobiSim) are used to generate the mobility pattern for VANETs.
... Performance of the selected protocols are then analysed and compared using the proposed model. In [15], a new routing link metric is designed, and in [16], a new quality link metric called inverse expected transmission count (InvETX) is proposed. The main contribution of [16] is improvement of the optimized link state routing (OLSR) protocol in terms of optimized routing load and routing latency. ...
One of the most important issues in wireless sensor networks (WSNs) is to reduce energy consumption and increase the network lifetime. Proper election of cluster head is one of the approaches to reduce energy consumption in the network. Among existing methods, low-energy adaptive cluster hierarchy (LEACH) is the most prevalent routing algorithm, in which the cluster head is elected based on a given threshold. In LEACH algorithm, only the cluster heads are allowed to send information to the base station (BS). In this paper, a novel routing protocol based on super cluster head election using fuzzy logic in three levels (SCHFTL) is proposed, in which a super cluster head is elected among the cluster heads. The super cluster head election is performed based on a fuzzy description in three levels using Mamdani inference engine. Effectiveness of the proposed SCHFTL routing protocol is verified through MATLAB simulations in terms of death, time of the first node and network lifetime compared with LEACH, cluster head election mechanism using fuzzy logic (CHEF) and fuzzy-based master cluster head election leach (F-MCHEL) protocols.
... where En is the initial energy of any of the four energy levels, r is the node at a specific energy level, ET X p is the expected transmission count [42] of a path P , InvET X p is the inverse expected transmission count [43], and MLp is the minimum loss [44]. The P metric values for the hybrid, high, medium, and low energy level nodes are given by Eqs. 19, 20, 21, and 22, respectively. ...
Wireless sensor networks (WSNs) have gained much attention in today’s research domain for supporting a wide variety of applications including the multimedia applications. Multimedia applications that are regarded as the quality-ofservice (QoS)-aware, delay sensitive, and bandwidth hungry applications, require enough energy and communication resources. WSNs being the energy-scarce network have now been designed in such a way that they can support these delay-sensitive and time-critical applications. In this paper, we propose an energyefficient routing protocol for heterogeneous WSNs to support the delay sensitive, bandwidth hungry, time-critical, and QoSaware applications. The proposed QoS-aware and heterogeneously clustered routing (QHCR) protocol not only conserves the energy in the network, but also provides the dedicated paths for the real-time and delay sensitive applications. The inclusion of different energy-levels for the heterogeneous WSNs also provide the stability in the networks while minimizing the delay for the delay-sensitive applications. Extensive simulations have been performed to validate the effectiveness of our proposed scheme. Our proposed routing scheme outperforms other state-of-the-art schemes in terms of the delay performances.
... Koksal et al. [5] presented a modified ETX metric, which combined the average and the variability of the error probability to optimize the decision results. Javaid et al. [6] presented a comprehensive study on the design requirements for routing link metrics and an inverse ETX (invETX) link metric for wireless multi-hop networks. In Boushaba et al. [7], considered the packet loss, intraflow and interflow interference, and load at gateways to select the best paths to reach the selected gateways and present a novel source-based routing (SBR) metric method. ...
The routing protocol is one of the most important aspects of the wireless sensor network, determining network connectivity, delay, energy balancing, reliability and other factors. Furthermore, a minimum hop-count does not mean minimum delay and energy consumption. To overcome the routing protocol’s shortcomings, we proposed an energy-efficient expected transmission count routing decision strategy (E³TX) for wireless sensor networks. E³TX makes use of two physical parameters, received signal strength indicator (RSSI) and battery voltage, to obtain the final decision via our proposed decision strategy. In our strategy, the received signal strength indicator is used to predict the future packet reception rate (PRR), and the battery voltage is used to estimate the residual energy of network nodes to balance their load. In order to estimate the packet reception rate via the received signal strength indicator with greater accuracy, we performed multiple experiments to build the relationship model between RSSI and PRR. In this article, we use NS-2.35 to evaluate and compare the performance of E³TX with AODV, AOMDV and BIETX. Our simulation results show that our proposed E³TX performs well when compared to the previous studies, not only in terms of energy consumption, but also in reliable data transmission and end-to-end delay.
... These metrics trade-off between different performance parameters, the computational burden of some metrics also degrades the performance of the respective protocol [9]. Considering that the functionality of SG is dependent on the ability of different applications meeting certain performance requirements, proposing multiple metric implemented within the existing routing protocols can guarantee the QoS of the variety of traffic in SG AMI network. ...
Routing in Neighbourhood Area Network (NAN) for Smart Grid's Advanced Metering Infrastructure (AMI) raises the need for Quality of Service (QoS)-Aware routing. This is due to the expanded list of applications that will result in the transmission of different types of traffic between NAN devices (i.e smart meters). In wireless mesh network (WMN) routing, a combination of multiple link metrics, though complex, has been identified as a possible solution for QoS routing. These complexities (i.e Np complete problem) can be resolved through the use of Analytical Hierarchy Process (AHP) algorithm and pruning techniques. With the assumption that smart meters transmit IP packets of different sizes at different interval to represent AMI traffic, a case study of the performance of three Optimised Link State Routing (OLSR) link metrics is carried out on a grid topology NAN based WMN in ns-2 network simulator. The best two performing metric were used to show the possibility of combining multiple metrics with OLSR through the AHP algorithm to fulfill the QoS routing requirements of targeted AMI application traffic in NANs.
... In this paper, the scenario we have presented is through the motivation of [24] and [25]. In [26], they have done evaluation of protocols through radio propagation model Nakagami which is well suited for all these models. ...
In this paper, a novel framework is presented through link and path duration for link availability of paths. Further, we evaluate and analyze our work by varying the number of nodes, pause time and speed in VANETs. We select three routing protocols namely Ad-hoc On-demand Distance Vector (AODV), Dynamic Source Routing (DSR) and Fish-eye State Routing (FSR). Performance of these protocols is analyzed using Packet Delivery Ratio (PDR), Normalized Routing Overhead (NRO), End-to-End Delay (E2ED), Average Link Duration (ALD) and Average Path Duration (APD) against varying scalability, pause time and speed as performance metrices. We perform these simulations with NS-2 implementing Nakagami radio propagation model. The SUMO simulator is used to generate a random mobility pattern for VANETs. To find link duration and path duration we also use MATLAB. From the extensive simulations, we observe that AODV and DSR outperform better among all three routing protocols.
... In future, Routing Link Matrices can also be applied on this proposed technique. Routing can be done by adapting many different approaches as done in[14],[15]and[16]. Application of Routing Link Matrices on the proposed scheme can be useful in achieving efficient consumption of energy in the network. ...
In this paper, we propose Regional Energy Efficient Cluster Heads based on Maximum Energy (REECH-ME) Routing Protocol for Wireless Sensor Networks (WSNs). The main purpose of this protocol is to improve the network lifetime and particularly the stability period of the network. In REECH-ME, the node with the maximum energy in a region becomes Cluster Head (CH) of that region for that particular round and the number of the cluster heads in each round remains the same. Our technique outperforms LEACH [1] which uses probabilistic approach for the selection of CHs. We also implement the Uniform Random Distribution Model to find the packet drop to make this protocol more practical. We also calculate the confidence interval of all our results which helps us to visualize the possible deviation of our graphs from the mean value.
... Because, a link metric provides all available end-to-end paths and the best path information to the respective protocol. So, in future, we are interested to develop a new link metric, like [21] and [22]. ...
This paper evaluates and compares the performance of two routing protocols, one is reactive, Dynamic MANET On-Demand (DYMO) and other is proactive, Optimized Link State Routing (OLSR) in Mobile Ad-hoc Networks (MANETs) and Vehicular Ad-hoc Networks (VANETs). Performance of these protocols is analyzed using three performance metrics; Packet Delivery Ratio, Normalized Routing Overhead and End-to-End Delay against varying scalabilities of nodes. We perform these simulations with NS-2 using TwoRayGround propagation model. The SUMO simulator is used to generate a random mobility pattern for VANETs. From the extensive simulations, we observe that DYMO performs better than OLSR for both VANETs and MANETs at the cost of delay. Moreover, DYMO performs better in VANETs as compared to MANETs.
... In future, we will implement different performance metrics of AM-DisCNT, as authors have done in [17], [18], [19] and [20]. ...
The nodes in wireless sensor networks (WSNs) contain limited energy
resources, which are needed to transmit data to base station (BS). Routing
protocols are designed to reduce the energy consumption. Clustering algorithms
are best in this aspect. Such clustering algorithms increase the stability and
lifetime of the network. However, every routing protocol is not suitable for
heterogeneous environments. AM-DisCNT is proposed and evaluated as a new energy
efficient protocol for wireless sensor networks. AM-DisCNT uses circular
deployment for even consumption of energy in entire wireless sensor network.
Cluster-head selection is on the basis of energy. Highest energy node becomes
CH for that round. Energy is again compared in the next round to check the
highest energy node of that round. The simulation results show that AM-DisCNT
performs better than the existing heterogeneous protocols on the basis of
network lifetime, throughput and stability of the system.
... On the other hand in MOD DSR due to reduction in the size of route. In future work, we are interested to implement Expected Transmission Count (ETX) link metric with mathematical modeling, as demonstrated in111213. ...
In this paper, a framework is presented for node distribution with respect to
density, network connectivity and communication time. According to modeled
framework we evaluate and compare the performance of three routing protocols;
Ad-hoc On-demand Distance Vector (AODV), Dynamic Source Routing (DSR) and
Fisheye State Routing (FSR) in MANETs and VANETs using two Mac-layer protocols;
802.11 and 802.11p. We have further modified these protocols by changing their
routing information exchange intervals; MOD AODV, MOD DSR and MOD FSR. A
comprehensive simulation work is performed in NS-2 for the comparison of these
routing protocols for varying mobilities and scalabilities of nodes. To
evaluate their efficiency; throughput, End-to-End Delay (E2ED) and Normalized
Routing Load (NRL) of these protocols are taken into account as performance
parameters. After extensive simulations, we observe that AODV outperforms both
with MANETs and VANETs.
... In this work, we study the three performance metrics: Network lifetime , Residual energy and throughput. In future, we will study ETX link metrics and we will implement this metric in our scheme as implemented and demonstrated in [21] [22] [23]. ...
In this research work, we advise gateway based energy-efficient routing
protocol (M-GEAR) for Wireless Sensor Networks (WSNs). We divide the sensor
nodes into four logical regions on the basis of their location in the sensing
field. We install Base Station (BS) out of the sensing area and a gateway node
at the centre of the sensing area. If the distance of a sensor node from BS or
gateway is less than predefined distance threshold, the node uses direct
communication. We divide the rest of nodes into two equal regions whose
distance is beyond the threshold distance. We select cluster heads (CHs)in each
region which are independent of the other region. These CHs are selected on the
basis of a probability. We compare performance of our protocol with LEACH (Low
Energy Adaptive Clustering Hierarchy). Performance analysis and compared
statistic results show that our proposed protocol perform well in terms of
energy consumption and network lifetime.
... Our simulation results shows that proposed routing scheme enhance the network stability time and packet delivered to sink. Path loss is also investigated in this protocol and in future work, we will implement Expected Transmission Count (ETX) link metrics as demonstrated in [22] [23] [24]. ...
In this work, we propose a reliable, power efficient and high throughput
routing protocol for Wireless Body Area Networks (WBANs). We use multi-hop
topology to achieve minimum energy consumption and longer network lifetime. We
propose a cost function to select parent node or forwarder. Proposed cost
function selects a parent node which has high residual energy and minimum
distance to sink. Residual energy parameter balances the energy consumption
among the sensor nodes while distance parameter ensures successful packet
delivery to sink. Simulation results show that our proposed protocol maximize
the network stability period and nodes stay alive for longer period. Longer
stability period contributes high packet delivery to sink which is major
interest for continuous patient monitoring.
... Future work focuses on estimating the delay in propagating data from body sensors to the destination node in DARE protocol and also to investigate mobility in patients body. Authors in [20][21][22][23], work on routing metrics based on ETX (Expected Transmission Count) which, shows better performance than minimum hop count metric, under the availability of link. In view of this, the plan focus to work on routing link metrics as well. ...
In recent years, interests in the applications of Wireless Body Area Sensor
Network (WBASN) is noticeably developed. WBASN is playing a significant role to
get the real time and precise data with reduced level of energy consumption. It
comprises of tiny, lightweight and energy restricted sensors, placed in/on the
human body, to monitor any ambiguity in body organs and measure various
biomedical parameters. In this study, a protocol named Distance Aware Relaying
Energy-efficient (DARE) to monitor patients in multi-hop Body Area Sensor
Networks (BASNs) is proposed. The protocol operates by investigating the ward
of a hospital comprising of eight patients, under different topologies by
positioning the sink at different locations or making it static or mobile.
Seven sensors are attached to each patient, measuring different parameters of
Electrocardiogram (ECG), pulse rate, heart rate, temperature level, glucose
level, toxins level and motion. To reduce the energy consumption, these sensors
communicate with the sink via an on-body relay, affixed on the chest of each
patient. The body relay possesses higher energy resources as compared to the
body sensors as, they perform aggregation and relaying of data to the sink
node. A comparison is also conducted conducted with another protocol of BAN
named, Mobility-supporting Adaptive Threshold-based Thermal-aware
Energy-efficient Multi-hop ProTocol (M-ATTEMPT). The simulation results show
that, the proposed protocol achieves increased network lifetime and efficiently
reduces the energy consumption, in relative to M-ATTEMPT protocol.
... In future, Routing Link Matrices can also be applied on this proposed technique. Routing can be done by adapting many different approaches as done in [14], [15] and [16]. Application of Routing Link Matrices on the proposed scheme can be useful in achieving efficient consumption of energy in the network. ...
In this paper, we propose Regional Energy Efficient Cluster Heads based on
Maximum Energy (REECH-ME) Routing Protocol for Wireless Sensor Networks (WSNs)
. The main purpose of this protocol is to improve the network lifetime and
particularly the stability period of the network. In REECH-ME, the node with
the maximum energy in a region becomes Cluster Head (CH) of that region for
that particular round and the number of the cluster heads in each round remains
the same. Our technique outperforms LEACH which uses probabilistic approach for
the selection of CHs. We also implement the Uniform Random Distribution Model
to find the packet drop to make this protocol more practical. We also calculate
the confidence interval of all our results which helps us to visualize the
possible deviation of our graphs from the mean value.
... Hence, THE-FAME gives better results in both energy and delay profiles as compared to multi-hop routing scheme. In future work, we will implement Expected Transmission Count (ETX) link metrics as demonstrated in [21] [22] [23] [24]. ...
Wireless Body Area Sensor Network (WBASN) is a technology employed mainly for
patient health monitoring. New research is being done to take the technology to
the next level i.e. player's fatigue monitoring in sports. Muscle fatigue is
the main cause of player's performance degradation. This type of fatigue can be
measured by sensing the accumulation of lactic acid in muscles. Excess of
lactic acid makes muscles feel lethargic. Keeping this in mind we propose a
protocol \underline{TH}reshold based \underline{E}nergy-efficient
\underline{FA}tigue \underline{ME}asurement (THE-FAME) for soccer players using
WBASN. In THE-FAME protocol, a composite parameter has been used that consists
of a threshold parameter for lactic acid accumulation and a parameter for
measuring distance covered by a particular player. When any parameters's value
in this composite parameter shows an increase beyond threshold, the players is
declared to be in a fatigue state. The size of battery and sensor should be
very small for the sake of players' best performance. These sensor nodes,
implanted inside player's body, are made energy efficient by using multiple
sinks instead of a single sink. Matlab simulation results show the
effectiveness of THE-FAME.
... Besides the evaluating the performance of DSDV, OLSR and DYMO we also made some modifications to these routing protocols and observed their performance at the end we came up with the result that with minor. In future, we are interested to apply the same analysis on quality link metrics proposed in9101112 and at MAC layer as [13, 14]. ...
In this paper, we present path loss model for VANETs and simulate three
routing protocols; Destination Sequenced Distance Vector (DSDV), Optimized Link
State Routing (OLSR) and Dynamic MANET On-demand (DYMO) to evaluate and compare
their performance using NS-2. The main contribution of this work is enhancement
of existing techniques to achieve high efficiency of the underlying networks.
After extensive simulations in NS-2, we conclude that DSDV best performs with
802.11p while DYMO gives outstanding performance with 802.11.
... On the other hand in MOD DSR due to reduction in the size of route cache improves overall performance in high speeds. In future, we are interested to apply the same analysis on quality link metrics proposed in101112 and at MAC layer as [13, 14]. a. MANET's NRL vs Scalibility b. ...
This paper presents a framework for node distribution with respect to
density, network connectivity and communication time. Using NS2, we evaluate
and compare performance of three routing protocols; Ad-hoc On-demand Distance
Vector (AODV), Dynamic Source Routing (DSR) and Fisheye State Routing (FSR)
both in MANETs (IEEE 802.11) and VANETs (IEEE 802.11p). We further enhanced
these protocols by changing their routing information exchange intervals; MOD
AODV, MOD DSR and MOD FSR. A comprehensive simulation work is performed for the
comparison of these routing protocols for varying motilities and scalabilities
of nodes. As a result, we can say that AODV outperforms DSR and FSR both in
MANETs and VANETs.
... Because, a link metric provides all available end-to-end paths and the best path information to the respective protocol. So, in future, we are interested to develop a new link metric, like [17] and [18]. ...
Mobile Ad-hoc NETworks (MANETs) comprise on wireless mobile nodes that are
communicating with each other without any infrastructure. Vehicular Ad-hoc
NETwork (VANET) is a special type of MANETs in which vehicles with high
mobility need to communicate with each other. In this paper, we present a novel
framework for link availability of paths for static as well as dynamic
networks. Moreover, we evaluate our frame work for routing protocols
performance with different number of nodes in MANETs and in VANETs. We select
three routing protocols namely Ad-hoc On-demand Distance Vector (AODV),
Fish-eye State Routing (FSR) and Optimized Link State Routing (OLSR).
Furthermore, we have also modified default parameters of selected protocols to
check their efficiencies. Performance of these protocols is analyzed using
three performance metrics; Packet Delivery Ratio (PDR), Normalized Routing
Overhead (NRO) and End-to-End Delay (E2ED) against varying scalabilities of
nodes. We perform these simulations with NS-2 using TwoRayGround propagation
model. The SUMO simulator is used to generate a random mobility pattern for
VANETs. From the extensive simulations, we observe that AODV outperforms among
all three protocols.
... Our simulation results show that DSR performs better at the cost of delay both in MANETs and in VANETs. In future, we are interested to develop a new link metric, like [16] and [17]. ...
In this paper, a framework for experimental parameters in which Packet
Delivery Ratio (PDR), effect of link duration over End-to-End Delay (E2ED) and
Normalized Routing Overhead (NRO) in terms of control packets is analyzed and
modeled for Mobile Ad-Hoc NETworks (MANETs) and Vehicular Ad-Hoc NETworks
(VANETs) with the assumption that nodes (vehicles) are sparsely moving in two
different road. Moreover, this paper contributes the performance comparison of
one Proactive Routing Protocol; Destination Sequenced Distance vector (DSDV)
and two reactive protocols; DYnamic Source Routing (DSR) and DYnamic MANET
On-Demand (DYMO). A novel contribution of this work is enhancements in default
versions of selected routing protocols. Three performance parameters; PDR, E2ED
and NRO with varying scalabilities are measured to analyze the performance of
selected routing protocols with their original and enhanced versions. From
extensive simulations, it is observed that DSR outperforms among all three
protocols at the cost of delay. NS-2 simulator is used for simulation with
TwoRayGround propagation model to evaluate analytical results.
... For delay sensitive applications, DYMO in reactive protocols and OLSR in proactive protocols are the plausible choices. During all this evaluation, we come to realize that the most important component of a routing protocol is routing link metric, so, future we are interested to propose and implement a new ETX-based routing link metric with AODV and OLSR, as discussed in [14], [15], [16]. ...
In this paper, we evaluate, analyze, and compare the impact of mobility on the behavior of three reactive protocols (AODV, DSR, DYMO) and three proactive protocols (DSDV, FSR, OLSR) in multi-hop wireless networks. We take into account throughput, end-to-end delay, and normalized routing load as performance parameters. Based upon the extensive simulation results in NS-2, we rank all of six protocols according to the performance parameters. Besides providing the interesting facts regarding the response of each protocol on varying mobilities and speeds, we also study the trade-offs, the routing protocols have to make. Such as, to achieve throughput, a protocol has to pay some cost in the form of increased end-to-end delay or routing overhead.
... While the reduction of network bandwidth utilization is more useful when data flows are increased. In future, we are interested to re-implement these reactive protocols with new routing link metric; IBETX (Interference and Bandwidth Adjusted Expected Transmission Count) [20] and Inverse ETX [21]. Because, these metrics have achieved reduced overhead by a proactive protocol Destination Sequenced Distance Vector (DSDV). ...
In this paper, we have modeled the routing over- head generated by three
reactive routing protocols; Ad-hoc On-demand Distance Vector (AODV), Dynamic
Source Routing (DSR) and DYnamic MANET On-deman (DYMO). Routing performed by
reactive protocols consists of two phases; route discovery and route
maintenance. Total cost paid by a protocol for efficient routing is sum of the
cost paid in the form of energy consumed and time spent. These protocols
majorly focus on the optimization performed by expanding ring search algorithm
to control the flooding generated by the mechanism of blind flooding. So, we
have modeled the energy consumed and time spent per packet both for route
discovery and route maintenance. The proposed framework is evaluated in NS-2 to
compare performance of the chosen routing protocols.
The Thirteenth International Conference on Wireless and Mobile Communications (ICWMC 2017), held between July 23 - 27, 2017 - Nice, France, followed on the previous events on advanced wireless technologies, wireless networking, and wireless applications.
ICWMC 2017 addressed wireless related topics concerning integration of latest technological advances to realize mobile and ubiquitous service environments for advanced applications and services in wireless networks. Mobility and wireless, special services and lessons learnt from particular deployment complemented the traditional wireless topics.
We take here the opportunity to warmly thank all the members of the ICWMC 2017 Technical Program Committee, as well as the numerous reviewers. The creation of such a high quality conference program would not have been possible without their involvement. We also kindly thank all the authors who dedicated much of their time and efforts to contribute to ICWMC 2017. We truly believe that, thanks to all these efforts, the final conference program consisted of top quality contributions.
Also, this event could not have been a reality without the support of many individuals, organizations, and sponsors. We are grateful to the members of the ICWMC 2017 organizing committee for their help in handling the logistics and for their work to make this professional meeting a success.
We hope that ICWMC 2017 was a successful international forum for the exchange of ideas and results between academia and industry and for the promotion of progress in the area of wireless and mobile communications.
We are convinced that the participants found the event useful and communications very open. We also hope that Nice provided a pleasant environment during the conference and everyone saved some time for exploring this beautiful city.
This dissertation endeavors to contribute enhancements in goodputsof the IEEE 802.11-based Wireless Multi-hop Networks (WMhNs).By performing exhaustive simulations, for the deep analysis and detailed assessment of both reactive (AODV, DSR, DYMO) and proactive (DSDV, FSR, OLSR) protocols for varying mobilities, speeds, network loads and scalabilities, it is observed that a routing link metric is a significant component of a routing protocol. In addition to finding all available paths, the fastest end-to-end route is selected by a link metric for the routing protocol. This study aims the quality routing. In the class of quality link metrics, Expected Transmission Count (ETX) is extensively used. Thus, the most recently proposed ETX-based metrics have been analyzed. Though, newly developed metrics over perform ETX but still they can be improved. By profound analysis and particularized comparison of routing protocols depending upon their classes (reactive and proactive) and ETX-based metrics, we come to realize that users always demand proficient networks. In fact, WMhNs are facing several troubles which they expect to be resolved by the routing protocol operating them. Consequently, the protocol depends upon the link metric for providing quality paths. So, we identify and analyze the requirements to design a new routing link metric for WMhNs. Because, considering these requirements, when a link metric is proposed, then : firstly, both the design and implementation of the link metric with a routing protocol become easy. Secondly, the underlying network issues can easily be tackled. Thirdly, an appreciable performance of the network is guaranteed. Keeping in view the issues of WMhNs, increasing demands of users and capabilities of routing protocols, we propose and implement a new quality link metric, Interference and Bandwidth Adjusted ETX (IBETX). As, MAC layer affects the link performance and consequently the route quality, the metric therefore, tackles the issue by achieving twofold MAC-awareness. Firstly, interference is calculated using cross-layered approach by sending probes to MAC layer. Secondly, the nominal bit rate information is provided to all nodes in the same contention domain by considering the bandwidth sharing mechanism of 802.11. Like ETX, our metric also calculates link delivery ratios that directly affect throughput and selects those routes that bypass dense regions in the network. Simulation results by NS-2 show that IBETX gives 19% higher through put than ETX and 10% higher than Expected Throughput (ETP). Our metric also succeeds to reduce average end-to-end delay up to 16% less than Expected Link Performance (ELP) and 24% less than ETX
Wireless ad-hoc networks are characterized by a collection of wireless mobile nodes that dynamically form a temporary network without the use of any pre-defined network infrastructure or centralized administration. They have attributes such multi-hop wireless connectivity, continuously changing topology and easy deployment. The increasing demands that are made by users pose a challenge in the improvement of the quality of wireless ad-hoc networks. The performance of wireless ad-hoc networks depend on the efficiency of routing protocols, especially the routing metric operating within it. In this paper, the performance of the recently proposed routing metric Interference Bandwidth Adjusted Expected transmission count (IBETX) metric is compared with two prominent existing metrics, the Expected transmission count (ETX) and the Inverse Expected Transmission count (InvETX) over the Destination Sequenced Distance Vector (DSDV) routing protocol. The performance differentials are analysed using varying packet rates and node densities. From the simulations results, IBETX metric outperforms the ETX and InvETX metric because it implements the bandwidth sharing mechanism and makes use of the information available at the MAC layer. It can also be noted that it is very sensitive to data traffic rate. It performs well in low and medium node densities.
Self-Organizing Networks (SONs) are attractive for applications where flexibility, resilience, and a large network service area are required. In order to meet the requirements of those applications, the principal issue is to guarantee efficient routing in SONs. Hence, the design and selection of appropriate routing metrics is important. A mass of metrics have been proposed in the past several decades. Among all the metrics, Expected Transmission Count (ETX) has drawn the most attention. Since the proposal of ETX, many ETX-based or extended metrics have been proposed. ETX and its descendants compose the ETX family. This paper is an attempt to analyze, compare and summarize traffic-based routing metrics in the ETX family. Details of each routing metric are presented and analyzed. Some of our viewpoints on the principal for designing metrics in SONs are presented.
Due to small size of sensor nodes deployed in Wireless Sensor Networks
(WSNs), energy utilization is a key issue. Poor channel conditions lead to
retransmissions and hence, result in energy wastage. Error control strategies
are usually utilized to accommodate channel impairments like noise and fading
in order to optimize energy consumption for network lifetime enhancement.
Meanwhile, cooperative communication also emerges to be an appropriate
candidate to combat the effects of channel fading. Energy efficiency of
cooperative scheme when applied with Automatic Repeat Request (ARQ), Hybrid-ARQ
(HARQ) and Forward Error Correction (FEC) is investigated in this work.
Moreover, the expressions for energy efficiency of Direct Transmission, Single
Relay Cooperation and Multi Relay Cooperation are also derived. In all, our
work is focused towards energy optimal communication in WSNs. Our results show
that error control strategies with cooperative schemes can significantly
enhance system performance in form of energy optimization.
Due to small size of sensor nodes deployed in Wireless Sensor Networks (WSNs), energy utilization is a key issue. Poor channel conditions lead to retransmissions and hence, result in energy wastage. Error control strategies are usually utilized to accommodate channel impairments like noise and fading in order to optimize energy consumption for network lifetime enhancement. Meanwhile, cooperative communication also emerges to be an appropriate candidate to combat the effects of channel fading. Energy efficiency of cooperative scheme when applied with Automatic Repeat Request (ARQ), Hybrid-ARQ (HARQ) and Forward Error Correction (FEC) is investigated in this work. Moreover, the expressions for energy efficiency of Direct Transmission, Single Relay Cooperation and Multi Relay Cooperation are also derived. In all, our work is focused towards energy optimal communication in WSNs. Our results show that error control strategies along with the cooperative scheme significantly enhances system performance in the form of energy optimization.
In this paper, we present a detailed framework consisting of modeling of
routing overhead generated by three widely used proactive routing protocols;
Destination-Sequenced Distance Vector (DSDV), Fish-eye State Routing (FSR) and
Optimized Link State Routing (OLSR). The questions like, how these protocols
differ from each other on the basis of implementing different routing
strategies, how neighbor estimation errors affect broadcast of route requests,
how reduction of broadcast overhead achieves bandwidth, how to cope with the
problem of mobility and density, etc, are attempted to respond. In all of the
above mentioned situations, routing overhead and delay generated by the chosen
protocols can exactly be calculated from our modeled equations. Finally, we
analyze the performance of selected routing protocols using our proposed
framework in NS-2 by considering different performance parameters; Route
REQuest (RREQ) packet generation, End-to-End Delay (E2ED) and Normalized
Routing Load (NRL) with respect to varying rates of mobility and density of
nodes in the underlying wireless network.
This document describes the Optimized Link State Routing (OLSR)
protocol for mobile ad hoc networks. The protocol is an optimization
of the classical link state algorithm tailored to the requirements of
a mobile wireless LAN. The key concept used in the protocol is that
of multipoint relays (MPRs). MPRs are selected nodes which forward
broadcast messages during the flooding process. This technique
substantially reduces the message overhead as compared to a classical
flooding mechanism, where every node retransmits each message when it
receives the first copy of the message. In OLSR, link state
information is generated only by nodes elected as MPRs. Thus, a
second optimization is achieved by minimizing the number of control
messages flooded in the network. As a third optimization, an MPR
node may chose to report only links between itself and its MPR
selectors. Hence, as contrary to the classic link state algorithm,
partial link state information is distributed in the network. This
information is then used for route calculation. OLSR provides
optimal routes (in terms of number of hops). The protocol is
particularly suitable for large and dense networks as the technique
of MPRs works well in this context.
This document describes the Optimized Link State Routing (OLSR)
protocol for mobile ad hoc networks. The protocol is an optimization
of the classical link state algorithm tailored to the requirements of
a mobile wireless LAN. The key concept used in the protocol is that
of multipoint relays (MPRs). MPRs are selected nodes which forward
broadcast messages during the flooding process. This technique
substantially reduces the message overhead as compared to a classical
flooding mechanism, where every node retransmits each message when it
receives the first copy of the message. In OLSR, link state
information is generated only by nodes elected as MPRs. Thus, a
second optimization is achieved by minimizing the number of control
messages flooded in the network. As a third optimization, an MPR
node may chose to report only links between itself and its MPR
selectors. Hence, as contrary to the classic link state algorithm,
partial link state information is distributed in the network. This
information is then used for route calculation. OLSR provides
optimal routes (in terms of number of hops). The protocol is
particularly suitable for large and dense networks as the technique
of MPRs works well in this context.
This work is based on measurements of the ReMesh wireless mesh network deployed over the city of Niterói, Brazil. It uses a modified version of the OLSR ad hoc routing protocol. OLSR has the goal of maximizing throughput by minimizing the number of transmissions over the wireless shared medium selecting routes based on the sum of the expected transmission count (ETX) of each link from a source node towards a destination node. Because of routing instabilities and the high packet loss rates (PLR) observed with the original OLSR algorithm, this work uses an algorithm for selecting multi-hop paths based on minimum loss probability along the entire path. Test results show that the mesh network performance has been improved, leading to more stable routes, lower packet loss rates, shorter delays and in many cases a small increase in network throughput.
Designing routing metrics is critical for perfor-mance in wireless mesh networks. The unique characteristics of mesh networks, such as static nodes and the shared nature of the wireless medium, invalidate existing solutions from both wired and wireless networks and impose unique requirements on designing routing metrics for mesh networks. In this paper, we focus on identifying these requirements. We first analyze the possible types of routing protocols that can be used and show that proactive hop-by-hop routing protocols are the most appropriate for mesh networks. Then, we examine the requirements for designing routing metrics according to the characteristics of mesh networks and the type of routing protocols used. Finally, we study several existing routing metrics, including hop count, ETX, ETT, WCETT and MIC in terms of their ability to satisfy these requirements. Our simulation results of the performance of these metrics confirm our analysis of these metrics.
Wireless mesh networks (WMNs) can be used in many different ap-plications. However, they lack standards and, as a consequence, a number of issues must still be addressed to ensure the proper functioning of these networks. Amongst these issues, routing is this paper's main concern. Thus, we propose the use of multiple metrics with the proactive Optimized Link State Routing (OLSR) protocol, in order to provide quality of service routing. Even though it has already been proved that routing with multiple metrics is an NP-complete problem, we show how the techniques of Analytic Hierarchy Process (AHP) and Pruning may be combined to perform multiple-metric routing, offering the best available routes based on the considered metrics. A study on the performance of the metrics considered for the proposal is also carried out in the NS simulator.
Multi-hop wireless mesh networks are increasingly being deployed for last-mile Internet access. Typically, network algorithms such as routing, channel assignment and topology control for such net- works rely heavily on metrics that intend to capture link "quality" across the network. However, the underlying dynamics of the pro- posed link metrics themselves have not yet been studied in detail. In this paper, we study the dynamics of the most popular link metrics in real network deployments. Using two wireless mesh testbeds, we measure a number of link metrics across different hardware plat- forms and network environments. The collected measurements al- low us to study the stability and sensitivity of the different metrics to various conditions. Our study provides several insights and fu- ture research directions on how network algorithms need to adapt to link dynamics as well as how popular and widely used link metrics can be improved.
Routing protocols for wireless ad hoc networks have traditionally focused on finding paths with minimum hop count. However, such paths can include slow or lossy links, leading to poor throughput. A routing algorithm can select better paths by explicitly taking the quality of the wireless links into account. In this paper, we conduct a detailed, empirical evaluation of the performance of three link-quality metrics---ETX, per-hop RTT, and per-hop packet pair---and compare them against minimum hop count. We study these metrics using a DSR-based routing protocol running in a wireless testbed. We find that the ETX metric has the best performance when all nodes are stationary. We also find that the per-hop RTT and per-hop packet-pair metrics perform poorly due to self-interference. Interestingly, the hop-count metric outperforms all of the link-quality metrics in a scenario where the sender is mobile.
One of the main problems faced by ad hoc networks is providing specific quality of service guarantees for multimedia applications, mainly due to factors such as radio signal fading and node mobility. Since mesh networks are a special type of ad hoc network, they inherit these networks' problems. This paper's main goal is to present OLSR-MD, an extension to OLSR (optimized link state routing), to provide quality of service based on link delay measurements. An evaluation of OLSR-MD in a mesh network to be deployed at the Federal University of Para, by means of ns2 (version 2.30) simulations, showed that this protocol performed better than other OLSR based alternatives studied in the simulations.
We present a new metric for routing in multi-radio, multi-hop wireless networks. We focus on wireless networks with stationary nodes, such as community wireless networks.The goal of the metric is to choose a high-throughput path between a source and a destination. Our metric assigns weights to individual links based on the Expected Transmission Time (ETT) of a packet over the link. The ETT is a function of the loss rate and the bandwidth of the link. The individual link weights are combined into a path metric called Weighted Cumulative ETT (WCETT) that explicitly accounts for the interference among links that use the same channel. The WCETT metric is incorporated into a routing protocol that we call Multi-Radio Link-Quality Source Routing.We studied the performance of our metric by implementing it in a wireless testbed consisting of 23 nodes, each equipped with two 802.11 wireless cards. We find that in a multi-radio environment, our metric significantly outperforms previously-proposed routing metrics by making judicious use of the second radio.
Many wireless sensor network applications must resolve the inherent conflict between energy efficient communication and the need to achieve desired quality of service such as end-to-end communication delay. To address this challenge, we propose the real-time power-aware routing (RPAR) protocol, which achieves application-specified communication delays at low energy cost by dynamically adapting transmission power and routing decisions. RPAR features a power-aware forwarding policy and an efficient neighborhood manager that are optimized for resource-constrained wireless sensors. Moreover, RPAR addresses important practical issues in wireless sensor networks, including lossy links, scalability, and severe memory and bandwidth constraints. Simulations based on a realistic radio model of MICA2 motes show that RPAR significantly reduces the number of deadlines missed and energy consumption compared to existing real-time and energy-efficient routing protocols
Load balancing is critical for improving performance in wireless mesh networks. The unique characteristics of mesh networks, such as static nodes and the shared nature of the wireless medium, invalidate existing solutions from both wired and wireless networks and introduce new challenges for providing load balancing. In this paper, we focus on addressing these challenges. We first formulate the objective of load balancing in mesh networks and provide a theoretical solution to optimally achieve this objective. Then, we investigate some existing practical approaches to load balancing in mesh networks and show that none of them sufficiently address these challenges and some may even cause non-optimal paths and forwarding loops. In response, we propose a new path weight function, called MIC, and a novel routing scheme, called LIBRA, to provide interference-aware and multi-channel/multi-radio aware load balancing for mesh networks, while still ensuring routing optimality and loop-freedom. We use extensive simulations to evaluate our scheme by comparing it with both the theoretical optimal solution and existing practical solutions. The results show close-to-optimum performance and indicate that LIBRA is a good candidate for load balancing and routing in wireless mesh networks.
Besides energy constraint, wireless sensor networks should also be able to provide bounded communication delay when they are used to support real-time applications. In this paper, a new routing metric is proposed. It takes into account both energy and delay constraints. It can be used in AODV. By mathematical analysis and simulations, we have shown the efficiency of this new routing metric.
The lifetime of a mobile ad hoc network (MANET) depends on the durability of the battery resource of the mobile hosts. Earlier research has proposed several routing protocols specifically on MANET, but most studies have not focused on the limitations of battery resource. We propose a new energy-aware routing protocol, which can increase the durability of the energy resource and, therefore, the lifetime of the mobile hosts and the MANET. The proposed protocol can conserve energy by shortening the idle period of the mobile hosts without increasing the probability of packet loss or reducing routing fidelity. Simulation results indicate that this new energy-conserving protocol can extend the lifetime of a MANET
A mobile, multi-hop wireless computer network, also termed an
ad-hoc network, can be envisioned as a collection of routers, equipped
with wireless transmitter/receiver, which are free to move about
arbitrarily. The basic assumption in an ad-hoc network is that some
nodes willing to communicate may be outside the wireless transmission
range of each other but may be able to communicate if other nodes in the
network are willing to forward packets from them. However, the
successful operation of an ad-hoc network will be hampered if an
intermediate node, participating in a communication between two nodes,
moves out of range suddenly or switches itself off in between message
transfer. The objective of this paper is to introduce a parameter,
affinity that characterizes the strength of relationship between two
nodes and to propose a distributed routing scheme between two nodes in
order to find a set of paths between them which are more stable and less
congested in a specific context. Thus, the communication in an ad-hoc
wireless network can be effective by making the nodes in the system
communication-aware in the sense that each node should know its affinity
with its neighbors and should be aware of the impact of its movement on
the communication structure of the underlying network
An ad-hoc network is the cooperative engagement of a collection of Mobile Hosts without the required intervention of any centralized Access Point. In this paper we present an innovative design for the operation of such ad-hoc networks. The basic idea of the design is to operate each Mobile Host as a specialized router, which periodically advertises its view of the interconnection topology with other Mobile Hosts within the network. This amounts to a new sort of routing protocol. We have investigated modifications to the basic BellmanFord routing mechanisms, as specified by the Routing Information Protocol, making it suitable for a dynamic and self-starting network mechanism as is required by users wishing to utilize ad-hoc networks. Our modifications address some of the previous objections to the use of Bellman-Ford, related to the poor looping properties of such algorithms in the face of broken links and the resulting time dependent nature of the interconnection topology describing th...
Next generation fixed wireless broadband networks are being increasingly deployed as mesh networks in order to provide and extend access to the internet. These networks are characterized by the use of multiple orthogonal channels and nodes with the ability to simultaneously communicate with many neighbors using multi- ple radios (interfaces) over orthogonal channels. Networks based on the IEEE 802.11a/b/g and 802.16 standards are examples of these systems. However, due to the limited number of available or- thogonal channels, interference is still a factor in such networks. Recent results have attempted to characterize the achievable ca- pacity of such networks, both in the deterministic(1) and asymp- totic(2) sense. In this paper, we build on these previous works and provide an experimental verification of asymptotic capacity result in (2) by using the deterministic model first proposed in (1). Our simulation results are based on a novel joint channel assignment and scheduling algorithm which is shown to achieve near-optimal capacity limits in random network topologies. The results in this paper are the first to provide an experimental verification of the- oretical results in (2) and give an insight into the behavior of the capacity region of a multi-hop multi-radio mesh network.
Wireless technologies, such as IEEE 802.11a, that are used in ad hoc networks provide for multiple non-overlapping channels. Most ad hoc network protocols that are currently available are designed to use a single channel. However, the available network capacity can be increased by using multiple channels. This paper presents new protocols specifically designed to exploit multiple channels. Our protocols simplify the use of multiple channels by using multiple interfaces, although the number of interfaces per host is typically smaller than the number of channels. We propose a link layer protocol to manage multiple channels, and it can be implemented over existing IEEE 802.11 hardware. We also propose a new routing metric for multi-channel multi-interface networks, and the metric is incorporated into an on-demand routing protocol that operates over the link layer protocol. Simulation results demonstrate the effectiveness of the proposed approach in significantly increasing network capacity, by utilizing all the available channels, even when the number of interfaces per host is smaller than the number of channels.
Being most popular and IETF standard metric, minimum hop count is appropriately used by ad hoc networks, as new paths must rapidly be found in the situations where quality paths could not be found in due time due to high node mobility. There always has been a tradeoff between throughput and energy consumption, but stationary topology of WMNs and high node density of WSN's benefit the algorithms to consider quality-aware routing to choose the best routes. In this paper, we analytically review ongoing research on wireless routing metrics which are based on ETX (expected transmission count) as it performs better than minimum hop count under link availability. Performances over ETX, target platforms and design requirements of these ETX based metrics are high-lighted. Consequences of the criteria being adopted (in addition to expected link layer transmissions & retransmissions) in the form of incremental: (1) performance overheads and computational complexity causing inefficient use of network resources and instability of the routing algorithm, (2) throughput gains achieved with better utilization of wireless medium resources have been elaborated.
The use of Fish eye scoping has been introduced to reduce the overhead of the OLSR routing protocol. This simple method is based on reducing the scope (TTL) of some topology updates, thus giving routers a precise view of their close neighborhood and a more and more approximate view of farther nodes. Fish Eye OLSR (OFLSR) has been showed to have excellent scaling properties and low network overhead. However, if deployed in relatively sparse networks, this scoping limitation of topology updates can result in long living routing loops, thus limiting the potential applications of such mechanisms in some practical wireless mesh networks. In this paper, we address the transient mini-loop problem due to fisheye scoping. We first analyze the occurrence of mini-loops. We discuss potential solutions and propose a pragmatic and distributed off-line heuristic, which allows each router to compute ldquosaferdquo scope for topology updates. With our method, every mesh router calculates in advance the minimum TTL value that avoids mini-loops at the ldquoscoperdquo boundary - optimal scope that will be set for generating topology update message whenever a neighbor link lost is detected. Simulations show that the proposed algorithm drastically improves safety of Fish Eye OLSR while still retaining its scaling and performance properties.
Finding a path with enough throughput in multihop wireless ad hoc networks is a critical task of QoS Routing. Previous studies on routing algorithms focused on networks with a single channel rate. The capability of supporting multiple channel rates, which is common in wireless systems, has not been carefully studied in routing algorithms. In this paper, we first carry out a comprehensive study on the impacts of multiple rates, interference and packet loss rate on the maximum end-to-end throughput or path capacity. A linear programming problem is formulated to determine the path capacity of any given path. This problem is also extended to a joint routing and link scheduling optimization problem to find a path with the largest path capacity. We show that interference clique transmission time is inversely proportional to the upper bound of the path capacity, and hence we propose to use it as a new routing metric. Moreover, we evaluate the capability of various routing metrics such as hop count, expected transmission times, end-to-end transmission delay or medium time, link rate, bandwidth distance product, and interference clique transmission time to discover a high throughput path. The results show that different routing metrics lead to paths with significantly different path capacity, and the interference clique transmission time tends to discover paths with higher throughput than other metrics.
Next generation fixed wireless broadband networks are being increasingly deployed as mesh networks in order to provide and extend access to the internet. These networks are characterized by the use of multiple orthogonal channels and nodes with the ability to simultaneously communicate with many neighbors using multiple radios (interfaces) over orthogonal channels. Networks based on the IEEE 802.11a/b/g and 802.16 standards are examples of these systems. However, due to the limited number of available orthogonal channels, interference is still a factor in such networks. In this paper, we propose a network model that captures the key practical aspects of such systems and characterize the constraints binding their behavior. We provide necessary conditions to verify the feasibility of rate vectors in these networks, and use them to derive upper bounds on the capacity in terms of achievable throughput, using a fast primal-dual algorithm. We then develop two link channel assignment schemes, one static and the other dynamic, in order to derive lower bounds on the achievable throughput. We demonstrate through simulations that the dynamic link channel assignment scheme performs close to optimal on the average, while the static link channel assignment algorithm also performs very well. The methods proposed in this paper can be a valuable tool for network designers in planning network deployment and for optimizing different performance objectives.
In this paper, we propose a new quality link metric, interference and bandwidth adjusted ETX (IBETX) for wireless multi-hop networks. As MAC layer affects the link performance and consequently the route quality, the metric therefore, tackles the issue by achieving twofold MAC-awareness. Firstly, interference is calculated using cross-layered approach by sending probes to MAC layer. Secondly, the nominal bit rate information is provided to all nodes in the same contention domain by considering the bandwidth sharing mechanism of 802.11. Like ETX, our metric also calculates link delivery ratios that directly affect throughput and selects those routes that bypass dense regions in the network. Simulation results by NS-2 show that IBETX gives 19% higher throughput than ETX and 10% higher than Expected Throughput (ETP). Our metric also succeeds to reduce average end-to-end delay up to 16% less than Expected Link Performance (ELP) and 24% less than ETX.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004. Vita. Includes bibliographical references (leaves 111-118). This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. The expected transmission count (ETX) metric is a new route metric for finding high-throughput paths in multi-hop wireless networks. The ETX of a path is the expected total number of packet transmissions (including retransmissions) required to successfully deliver a packet along that path. For practical networks, paths with the minimum ETX have the highest throughput. The ETX metric incorporates the effects of link loss ratios, asymmetry in the loss ratios between the two directions of each link, and interference among the successive links of a path. Busy networks that use the ETX route metric will also maximize total network throughput. We describe the design and implementation of ETX as a metric for the DSDV and DSR routing protocols, as well as modifications to DSDV and DSR which make them work well with ETX. Measurements taken from a 29-node 802.11b test-bed show that using ETX improves performance significantly over the widely-used minimum hop-count metric. For long paths the throughput increase is often a factor of two or more, suggesting that ETX will become more useful as networks grow larger and paths become longer. We also present a simple model for predicting how packet delivery ratio varies with packet size, and detailed measurements which characterize the test-bed's distribution of link delivery ratios and route throughputs. by Douglas S.J. Couto. Ph.D.
There has been increased interest recently from military, civil,
and commercial sectors in networks capable of self-organization. Routing
and channel assignment for multi-hop communications in these networks
are complex problems, given the interactions between the various
transmissions, all of which must share some fixed bandwidth, and by the
lack of a central controller. By enforcing a “reuse
distance” similar to the frequency reuse factor in AMPS cellular
service, we can route and assign channels to (place) arriving calls in a
peer-to-peer network so as to significantly reduce power requirements
and interference
Using multiple metrics with the optimized link state routing protocol for wireless mesh networks
- W Moreira
- E Aguiar
- A Abelm
- M Stanton