Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Sensor networks are meant for sensing and disseminating information about the environment they sense. The criticality of a sensed phenomenon determines its importance to the end user. Hence, data dissemination in a sensor network should be information aware. Such information awareness is essential firstly to disseminate critical information more reliably and secondly to consume network resources proportional to the criticality of information. In this paper, we describe a protocol called RelnForM to deliver packets at desired reliability at a proportionate communication cost. RelnForm sends multiple copies of each packet along multiple paths from source to sink, such that data is delivered at the desired reliability. It uses the concept of dynamic packet state in context of sensor networks, to control the number of paths required for the desired reliability, and does so using only local knowledge of channel error rates and topology. We show that for uniform unit disk graphs, the number of edge-disjoint paths between nodes is equal to the average node degree with very high probability. RelnForm utilizes this property in its randomized forwarding mechanism which results in use of all possible paths and efficient load balancing. <s> BIB001 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> In this paper, we present a real-time communication protocol for sensor networks, called SPEED. The protocol provides three types of real-time communication services, namely, real-time unicast, real-time area-multicast and real-time area-anycast. SPEED is specifically tailored to be a stateless, localized algorithm with minimal control overhead End-to-end soft real-time communication is achieved by maintaining a desired delivery speed across the sensor network through a novel combination of feedback control and non-deterministic geographic forwarding. SPEED is a highly efficient and scalable protocol for sensor networks where the resources of each node are scarce. Theoretical analysis, simulation experiments and a real implementation on Berkeley motes are provided to validate our claims. <s> BIB002 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Wireless sensor networks are being built to facilitate automated information gathering in military, industrial, environmental and surveillance applications. Many such applications of Sensor Networks require improved QoS (packet delivery within a defined deadline) guarantees as well as high reliability. These applications demand high packet delivery ratio and are extremely delay-sensitive. However, certain factors limit the ability of the multihop sensor network to achieve the desired goals. These factors include the delay caused by network congestion, hot regions in the network, limited energy of the sensor nodes, packet loss due to collisions and link failure. In this paper, we propose an energy aware dual-path routing scheme for real-time traffic, which balances node energy utilization to increase the network lifetime, takes network congestion into account to reduce the routing delay across the network and increases the reliability of the packets reaching the destination by introducing minimal data redundancy. This paper also introduces an adaptive prioritized Medium Access Layer (MAC) to provide a differentiated service model for real-time packets. Our claims are well supported by simulation results. <s> BIB003 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> In this paper, we present a novel packet delivery mechanism called Multi-Path and Multi-SPEED Routing Protocol (MMSPEED) for probabilistic QoS guarantee in wireless sensor networks. The QoS provisioning is performed in two quality domains, namely, timeliness and reliability. Multiple QoS levels are provided in the timeliness domain by guaranteeing multiple packet delivery speed options. In the reliability domain, various reliability requirements are supported by probabilistic multipath forwarding. These mechanisms for QoS provisioning are realized in a localized way without global network information by employing localized geographic packet forwarding augmented with dynamic compensation, which compensates for local decision inaccuracies as a packet travels towards its destination. This way, MMSPEED can guarantee end-to-end requirements in a localized way, which is desirable for scalability and adaptability to large scale dynamic sensor networks. Simulation results show that MMSPEED provides QoS differentiation in both reliability and timeliness domains and, as a result, significantly improves the effective capacity of a sensor network in terms of number of flows that meet both reliability and timeliness requirements up to 50 percent (12 flows versus 18 flows). <s> BIB004 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> 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. <s> BIB005 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> In this article, multipath multi-speed (MMSPEED) protocol will be considered as a wireless multimedia sensor network (WMSN) routing protocol. Experimental results show that MMSPEED protocol has significant potential in video applications but it does not compatible with special features of multimedia traffic such as high video frame rate, packet's information dependency and frames different reliability. Awareness of MMSPEED about of embedded information in the received packet can lead to better resource utilization in network and MAC layers. Simulation results show that video PSNR significantly increases due to multimedia-aware improvements over MMSPEED. <s> BIB006 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Image and video sensing data in the multimedia wireless sensor networks make many requirements in the resource of bandwidth and energy. For the purpose of real-time transmission of multimedia data, this paper proposes a new QoS protocol applied to multimedia wireless sensor networks REAR. In this protocol metadata is used to establish multi-path routing for reducing the energy consumption and a cost function is constructed to evaluate the consumption of the transmission links which trades off the relationship of energy and delay, and then a QoS routing is chosen. The experiments show that the protocol could ensure the real-time transmission of multimedia data and prolong the lifetime of sensor networks. <s> BIB007 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> As a novel information acquiring and processing technology, compared to other traditional sensor networks, wireless multimedia sensor networks pay more attention to the information-intensive data (e.g. audio, video, image). Potential applications of wireless multimedia sensor networks span a wide spectrum from military to industrial, from commercial to environmental monitoring. This paper discusses QoS routing problem model with multiple QoS constraints, which may deal with the delay, delay jitter and bandwidth, and presents QoS routing algorithm with multiple constraints based on genetic algorithm, and gives the algorithm idiographic flow. Simulating results show that higher routing successful ratio and faster convergence is achieved in the algorithm. <s> BIB008 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> In this paper, we propose an efficient Two-Phase geographic Greedy Forwarding (TPGF) routing algorithm for WMSNs. TPGF takes into account both the requirements of real time multimedia transmission and the realistic characteristics of WMSNs. It finds one shortest (near-shortest) path per execution and can be executed repeatedly to find more on-demand shortest (near-shortest) node-disjoint routing paths. TPGF supports three features: (1) hole-bypassing, (2) the shortest path transmission, and (3) multipath transmission, at the same time. TPGF is a pure geographic greedy forwarding routing algorithm, which does not include the face routing, e.g., right/left hand rules, and does not use planarization algorithms, e.g., GG or RNG. This point allows more links to be available for TPGF to explore more routing paths, and enables TPGF to be different from many existing geographic routing algorithms. Both theoretical analysis and simulation comparison in this paper indicate that TPGF is highly suitable for multimedia transmission in WMSNs. <s> BIB009 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Wireless Multimedia Sensor Network(WMSN) is a blooming field due to the development of CMOS cameras and Microphones which are wirelessly interconnected devices that are able to retrieve multimedia content such as video and audio streams, still images and scalar sensor data from the environment. As of today, almost all deployed wireless sensor data networks measure scalar physical parameters like temperature, pressure humidity etc. To capture the image, video Wireless Multimedia Sensor nodes (WMSn) are to be deployed. The node of WMSn is equipped with cameras, microphones, and sensors producing multimedia content. Routing in Wireless Sensor Network is an important issue since WMS nodes that senses the data need to be communicated to the base station. The key issues in design of routing protocol in the WMSN are energy efficiency, adaptive routing, multimedia packet scheduling, Quality of service (QOS) and high bandwidth demand. Many routing protocols have been proposed for the WMSN. The design of more efficient protocols in terms of energy awareness, video packet scheduling and QOS in terms of check point arrangement is still remains a challenge. This paper discuss the design of the routing protocol in wireless multimedia sensor network which is power aware, reliable and has low latency in delivering the sensing data from source or sink node to the destination node. The new proposed architecture called ASARC: ACTUATION SENSOR ADAPTIVE ROUTING WITH CHECK POINT. ASARC provides actuation of sensor on demand basis and selection of path for communication between any two nodes such as sensor or relay node without video distortion. This feature enhances the lifetime of the network and also it supports security and QOS. <s> BIB010 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Automated information gathering in military, industrial, environmental and surveillance applications which requires improved QoS guarantees as well as high reliability is well supported with Wireless Multimedia Sensor Networks (WMSNs). In this paper, we propose a more reliable energy efficient multi-path routing scheme for multimedia-traffic. The proposed protocol quickly chooses partial disjoint paths in case of node failure to minimize routing overhead. Hence increases the reliability of the packets reaching the destination with minimum delay. Extensive simulations are carried out to show that proposed protocol achieves an efficient tradeoff among reliability, energy consumption and end to end delay. It provides higher packet delivery ratios and lower routing overheads compared to the Maximally Radio disjoint Multipath Routing (MR2) and Hop Count Multipath routing (HCMR) protocols. <s> BIB011 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> The increase in the usefulness of WSNs, have lead to the transmission of multimedia content over these networks. This has escorted to the concept of Wireless Multimedia Sensor networks (WMSNs). Due to resource constrained structure of WSNs, special attention is required to route data in these networks. In this paper, we propose a novel routing protocol for WMSNs which establishes paths on the basis of traffic load, hop count and node energy. The protocol aims to find completely or partially disjoint paths for routing multimedia traffic with relatively minimum distance. Simulation results have shown that the proposed protocol is capable of finding intelligent path such that it increases throughput and avoid creation of network holes near the sink. <s> BIB012 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Recently, wireless multimedia sensor networks (WMSNs) have emerged as one of the most important technologies, driven by the development of powerful multimedia device such as CMOS. WMSNs require several factors such as resource constraints, specific QoS, high bandwidth and so on. In this paper, we propose a hierarchical heterogeneous network model based routing protocol for WMSNs. In our proposal, proposed network model is classified into monitoring class, delivery class and aggregation class. Also we define two kinds of the routing path in order to ensure bandwidth and QoS. In simulation results, we illustrate the performance of our proposal. <s> BIB013 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> In Wireless Multimedia Sensor Networks (WMSN), routing is essential to promote high data rate accommodation. During the query and data dissemination phases, optimal routing is a vital role since the multimedia content is conditional to strict QoS requirements. But the existing works on Multipath routing rarely consider losses and delay at the sink leading to energy degradation, involve unnecessary additional paths which cause high overhead. To overcome these issues, in this paper, we proposed an adaptive multi constraint Multipath routing protocol which minimizes loss rate, energy consumption and delay. We consider a cluster based architecture where inter cluster routing is performed based on a weighted cost function. The cost function is based on the parameters such as loss rate, residual energy and delay. In order to save energy, nodes which don't take part in routing are put to sleep mode. The simulation results prove that the proposed protocol is efficient in terms of energy efficiency, delay and packet delivery ratio when compared to the QoS aware routing from the literature. <s> BIB014 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Graphical abstractDisplay Omitted HighlightsA new multi-objective approach for the routing problem in Wireless Multimedia Sensor Networks (WMSNs) is proposed.Classical approximations optimize a single objective or Quality of Service (QoS) parameter.Classical approximations do not take into account the conflicting nature of QoS parameters which leads to sub-optimal solutions.The proposed approach takes into account multiple QoS requirements such as delay and the Expected Transmission Count (ETX).The case studies applying the proposed approach shows clear improvements on the QoS routing solutions. In this paper, a new multi-objective approach for the routing problem in Wireless Multimedia Sensor Networks (WMSNs) is proposed. It takes into account Quality of Service (QoS) requirements such as delay and the Expected Transmission Count (ETX). Classical approximations optimize a single objective or QoS parameter, not taking into account the conflicting nature of these parameters which leads to sub-optimal solutions. The case studies applying the proposed approach show clear improvements on the QoS routing solutions. For example, in terms of delay, the approximate mean improvement ratios obtained for scenarios 1 and 2 were of 15 and 28 times, respectively. <s> BIB015 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> “MAEE Routing Protocol for WMSNs”, routes image packets to the sink optimally, utilizing less energy of the node. MAEE uses MMRE+AOMDV protocol to build the multiple paths and then score them using path conditions based on availability of resources. Simulation is performed using ns-2.27 platform and results evaluated in the simulation demonstrate a significant performance parameter improvement. <s> BIB016 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Technological developments in the micro-electronics and wireless communications, in addition to obtain ability of cheap CMOS cameras and micro phones, have led to appearance of next generation networks known as Wireless Multimedia Sensor Networks (WMSNs). WMSN can retrieve image, video, audio and scalar sensor data from the physical environment. Wireless multimedia sensor networks will not only enhance existing sensor network applications like tracking, home automation, and environmental monitor, but they will also enable several new applications such as: Advanced Health Care Delivery, Industrial Process Control, Traffic Congestion Avoidance Systems. In this paper a technique called EEQAR is used to select energy efficient QoS routing which is based on cluster hierarchy. To achieve a enhanced performance, EEQAR routing implements cellular topology to form the cluster structure and balance the energy consumption by structure movement. The simulation results shows that EEQAR performs high efficiency on network lifetime and QoS in wireless multimedia sensor network. <s> BIB017 </s> Survey of QoS routing protocols in Wireless Multimedia Sensor Networks <s> Triple-Metric Link/Path Cost-Dependent Routing Protocols. <s> Wireless Multimedia Sensor Networks (WMSNs) consist of networks of interconnected devices involved in retrieving multimedia content, such as, video, audio, acoustic, and scalar data, from the environment. The goal of these networks is optimized delivery of multimedia content based on quality of service (QoS) parameters, such as delay, jitter and distortion. In multimedia communications each packet has strict playout deadlines, thus late arriving packets and lost packets are treated equally. It is a challenging task to guarantee soft delay deadlines along with energy minimization, in resource constrained, high data rate WMSNs. Conventional layered approach does not provide optimal solution for guaranteeing soft delay deadlines due to the large amount of overhead involved at each layer. Cross layer approach is fast gaining popularity, due to its ability to exploit the interdependence between different layers, to guarantee QoS constraints like latency, distortion, reliability, throughput and error rate. The paper presents a channel utilization and delay aware routing (CUDAR) protocol for WMSNs. This protocol is based on a cross-layer approach, which provides soft end-to-end delay guarantees along with efficient utilization of resources. Extensive simulation analysis of CUDAR shows that it provides better delay guarantees than existing protocols and consequently reduces jitter and distortion in WMSN communication. <s> BIB018
These types of QoS routing protocols make routing decision based on three metrics. Such schemes which determine link/path cost by a proper fusion of three metrics are categorized as triple-metric link/path cost-dependent routing schemes. Table 3 shows comparative summary of routing schemes under this category. ReInForM provides end-to-end reliability in the presence of channel errors using a packet duplication technique over randomly chosen multipaths BIB001 . Path selection is based on hop count toward the sink node, desired reliability, and local channel error rate. The source adds information in the packet header about these three metrics as the Dynamic Packet State (DPS) field. Along with the data, it transmits multiple copies of the same packet through multiple paths. At every intermediate node, DPS controls a number of paths for desired reliability; that is, after receiving each packet, every intermediate node will decide how many copies of the packet should be forwarded to neighboring nodes. Multiple path selection is performed randomly, which helps in load balancing. However, this protocol achieves reliability by duplicating packets, which consumes more bandwidth and more energy. Mahapatra et al. explore a reliable, dual path, energyaware, real-time routing scheme BIB003 . This scheme provides simple service differentiation using an adaptive, prioritized MAC layer. It finds the next forwarding node based on remaining distance, delay, and remaining energy. Here, the source node computes the priority for each neighboring node based on delay and remaining energy. Based on computed priority, the best two nodes are selected by the source node, which forwards a copy of the data packet to each of them. Intermediate nodes forward the data packet to only one best neighboring node, which results in minimization of duplicate data packets in the network. Current load or congestion in the neighboring nodes will be known from the exchange of HELLO PKT. Simple service differentiation is implemented using a prioritized MAC layer, which assigns higher priority to real-time packets. For random urgent packets, this scheme results in unacceptable path discovery latency. MMSPEED is a multipath, multispeed geographic protocol that guarantees reliability and timeliness with service differentiation BIB004 . In this work, the idea of SPEED BIB002 is extended to provide multiple delivery speed options for each incoming packet at the node. These speed options are mapped to MAC layer priority class. For timeliness, various speed options are available of which different traffic flows can choose options based on an end-to-end deadline. Probabilistic multipath forwarding is used, which compensates for local decision inaccuracies during the journey of a packet from source to destination. Intermediate nodes enhance the speed of the packet, resulting in meeting the delay deadline for that packet. Depending upon the reliability requirement, each node forwards multiple copies of a packet to selected neighbors. MMSPEED is further explored for multimedia-aware service differentiation in the network and MAC layer BIB006 . In multimedia-aware MMSPEED, routings paths are categorized into two types, namely, near optimum paths, which are dedicated to I-frames, and marginal paths, which are dedicated to P-frames. This differentiated routing is implemented with only two speeds. The higher speed is for I-frame packets, and the intermediate speed is for Pframe packets. Additionally, this differentiation is extended by the MAC layer using IEEE802.11e to maintain two separate queues. This work shows results with improved Peak Signalto-Noise Ratio (PSNR) or improved video quality for multiple flows. In both works, the number of hops and residual energy metrics are not considered in the routing decision. RPAR, or the Real-time Power-Aware Routing protocol, allows a tradeoff between communication delay and transmission power BIB005 . This tradeoff control is achieved by specifying packet deadlines. In RPAR, a packet is forwarded based on a dynamic velocity-assignment policy and a most energy-efficient policy. The velocity-assignment policy dynamically assigns required velocity to a packet based on current network conditions at every node. This dynamic assignment will result in assigning a logical priority to every packet in the queue. The transmission power of a sensor node is increased or decreased based on the velocity requirement. RPAR handles lossy links, bandwidth constraints, and memory constraints, but transmitting a packet at high power levels in RPAR increases interference, resulting in a decrease in throughput. Additionally, power adaption policy degrades performance when a node is congested. Real-time and Energy Aware Routing (REAR) is an eventdriven protocol that uses metadata instead of real data in path exploration BIB007 . It uses a link-cost evaluation function based on three metrics, namely, distance, remaining energy, and queuing delay of neighboring nodes. It uses an advanced Dijkstra's algorithm to find routes based on a link-cost function. Logical priority is implemented with the help of two queues, one for real-time data and the other for nonrealtime data. A metadata consultation mechanism between neighboring nodes is used to reduce energy consumption and queuing delay at every node. However, the metadata exchange mechanism is not a good option for multimedia streaming applications. In addition, this scheme does not support reliable data transmission. Another work by Dong at al. makes use of a genetic algorithm to understand the QoS routing for WMSNs BIB008 . It is based on a cluster network model consisting of functions, namely, encoding, production of the initial population, determination of fitness, method of selection, crossover operation, and mutation operation. For the initial population, it uses a random walk to find a routing path between source and destination. A fitness function depends on three metric parameters, namely, bandwidth, delay, and delay jitter. In this work, the convergence rate is vague with respect to the crossover probability. Since node energy is not considered in routing decision network may survive for less amount of period. Cluster-based ASARC supports actuating multimedia sensors to maximize event information with a minimum level of redundancy BIB010 . In the case of an event, a sensor actuation algorithm is used to actuate one or more multimedia sensor nodes from sleep mode. Routing path selection is based on residual power, distance, and routing delay with respect to the neighboring node. It uses a Reed-Solomon encoding scheme at the source throughout data transmission. To improve the data transmission rate, the source adapts a distortion prediction model. Using this model, the source decides which packets to drop to maintain distortion at a minimum level. Additionally, it implements a checkpoint feature in the sensor cluster, which periodically saves machine states and intermediate data. Because of extra overhead in ASARC, complexity level is high, and power consumption is not to the level of expectation. EEIAMR is a reliable multipath interference-aware routing algorithm that improves energy efficiency BIB011 . It discovers multiple paths based on the distance between neighboring nodes with respect to the sink, minimum hop count on the path, and residual energy. For the interference-aware feature, the neighboring node with maximum energy and farthest from the preceding node is chosen as the next intermediate node. Out of the multiple paths found, the source selects only one best path to forward the data. A selection of only one path limits the protocol to critical end-to-end delay applications. During data transmission, if the path node fails, then the previous node of the failed path finds an interference-aware alternate path without initiating a new route discovery phase. Less routing overhead reduces energy consumption in EEIAMR, resulting in improved network lifetime, but partial node-disjoint paths may result in energy failure of a common node, disabling these paths. In addition, less number of paths are discovered by EEIAMR. HLEAR is a Hop and Load-based Energy-Aware Reactive protocol with swarm intelligence BIB012 . It is based on a routing metric beta ( ), which is derived from the hop count, current traffic load, and residual energy of a node. A node with the lowest value is considered the best intermediate candidate on the path. Additionally, a node with four currently active routes is not permitted to participate in the route discovery process. Similarly, nodes with minimum cut-off residual energy are marked as swap nodes and are not allowed in the route discovery process, preventing the creation of holes near the sink. HLEAR is not scalable because it is based on a tabledriven approach. Another work by Kim et al. based on a heterogeneous hierarchical model uses two paths from the sensing node to the base station BIB013 . These two paths are the delivery path and the control path. The delivery path is used to send multimedia data from the source node to the base station via relay nodes. The next intermediate relay node is selected based on a cost function, which depends on distance, remaining energy, and bandwidth of a node. A relay node with one existing delivery path is not considered for the establishment of another delivery path. This criterion of only one delivery path through a relay node plays a significant role in the prevention of congestion in the network. However, command paths can be overlapped in one relay node because command data is very small compared with actual data. This protocol also uses security keys to protect against a fraudulent attacker causing an energy collapse of relay nodes. An isolation and recovery step during the establishment of a delivery path affects already-existing delivery paths that simply increase complexity and time. Additionally, the protocol consumes more energy because of the discovery of two different paths. AMPMCR is an adaptive multipath multiconstraint multitier hierarchical routing protocol BIB014 . Intercluster routing is based on a cost function that considers three metric parameters, namely, delay, loss rate, and remaining energy. Based on these metric values, paths are classified into delaysensitive paths, loss-sensitive paths, critical paths, and normal paths. If all three metric values provided by the paths are resourceful, then it is called a normal path. In case the path discovered is not a normal path, multiple paths are discovered. Additionally, depending upon network load, to boost the lifetime of the network, a few nodes in multipath routing are kept in the passive state. Simulation results show that AMPMCR minimizes packet loss rate, delay, and energy consumption. However, during multipath route discovery, it uses flooding, which consumes more energy. WMSNs routing is also achieved using multiobjective optimization algorithms BIB015 . Based on different objectives, a diverse set of optimal solutions is produced. Multiobjective routing is based on three metrics, namely, node delay, ETX, and number of hops on a path. It uses a genetic multiobjective evolutionary algorithm, called Strength Pareto Evolutionary Algorithm (SPEA). Here, a breadth-first search algorithm is used to create the initial population. Fitness values are based on ETX and delay, which is assigned to individual initial population samples. Crossover and mutation genetic operators are used to find feasible solutions. SPEA ensures better solutions in early runs, and it finds the path with minimum ETX and delay, satisfying both essential objectives. Because node energy is not considered in routing decision, network lifetime may be shorter. Maximal Minimal nodal Residual Energy-(MMRE-) AOMDV based Energy Efficient (MAEE) is a multipath, highly reliable protocol designed to transmit images in lossy networks BIB016 . Multiple routing paths are found based on residual energy, ETX, and buffer size of the node. Images are classified into two types, namely, Overlapping Region (OVR) images and Nonoverlapping Region (NOVR) images. Packets with OVR images are given higher priority over NOVR images. This protocol makes use of good quality links resulting into less packet loss, which increases throughput and decreases delay. However, MAEE is not scalable and is not entirely efficient to deliver images to the destination. Energy Efficient QoS Assurance Routing (EEQAR) is hierarchical protocol that aims to increase network lifetime BIB017 . Intracluster routing is based on three metrics, namely, remaining energy, QoS trust value, and data correlation coefficient. After each round, the location of cluster head varies resulting in restructuring of cluster topology. Nodes that are idle are put into sleep mode. For intercluster routing this protocol adapts TPGF BIB009 . Two types of Transmission Powers are used by the cluster heads, namely, the higher power level for intercluster routing and lower power level for intracluster routing. This protocol does not support packet priority and congestion. Also, contrary to the claim, results related to QoS are not presented and not compared with any previous protocols. Channel Utilization and Delay Aware Routing (CUDAR) is a multisource protocol that uses cross-layer approach to offer high throughput, better delay, and low jitter in WMSNs BIB018 . Forwarding node is selected based on crosslayer communication between the network layer and MAC layer. To reduce energy consumption, it uses adaptive channel utilization module in MAC layer. CUDAR uses only three routing metrics to achieve most relevant information about best forwarding node, that is, PST, channel utilization, and remaining energy. Nodes are chosen with lesser PST and contention which further reduces congestion and delay. Results show that throughput gradually increases with increase in the number of source nodes. However, relatively increase in network lifetime is not significant as compared to previous protocols.