We propose a Reinforcement Learning (RL) framework for hybrid truck-drone Last-Mile Delivery (LMD), where drones launch from a truck and either rendezvous with it or return to the depot after serving customers, subject to vehicle range limits and customer-defined deadlines. Deliveries completed after the latest allowable service time are treated as deadline violations (lateness) and are penalized in the objective. To provide an exact reference, a Mixed Integer Linear Programming (MILP) model is formulated. It serves both as a benchmark for evaluating the RL approach and as a practical method when the delivery set is small or when minimizing lateness is the primary objective, since the exact MILP solution is guaranteed to be optimal but become computationally expensive to solve as problem size grows due to the combinatorial increase in routing and coordination possibilities. The RL method is introduced as a scalable alternative for larger hybrid truck-drone deployments because it maintains practical computation times through iterative learning and avoids the exponential growth in solving effort associated with exact optimization. The RL framework employs an$\epsilon $-greedy policy with decay and a reward structure that mirrors the MILP objective. Traffic congestion is incorporated through a scaling matrix that adjusts truck travel times on road segments, while drones remain unaffected due to aerial operation. RL is further benchmarked against Genetic Algorithm (GA) and Particle Swarm Optimiztion (PSO), which are also formulated to align with the same MILP objective to ensure a consistent basis for comparison. Results show that the RL component scales more efficiently with increasing delivery size while maintaining competitive solution quality.

Closed-loop Distributed Denial-of-Service (DDoS) mitigation in Fifth Generation (5G) networks must balance attack blocking with operational safety by minimizing collateral damage to benign users. Network operators using the Network Data Analytics Function (NWDAF) face a dilemma: existing Machine Learning (ML)-based security solutions provide binary classifications but lack a mechanism to translate model outputs into quantifiable, proportional, and automated mitigation actions. This paper proposes a two-stage management framework that maps network analytics to graduated mitigation decisions using a risk-calibrated decision gate and severity-based policy thresholds. First, Isotonic Regression calibrates model outputs and triggers mitigation only for high-confidence detections, reducing false-positive harm. Second, for admitted threats, the Dynamic Mitigation Severity Score (DMSS) quantifies severity by aggregating normalized Shapley Additive exPlanations (SHAP) contributions of key 5G features. Thresholds optimized to minimize benign terminations select one of three actions: Terminate, Throttle, or Monitor. Experiments on a public 5G DDoS testbed show that, unlike deep learning baselines prone to severe collateral damage, the framework maintains high threat coverage while nearly eliminating benign terminations. Calibration further reduces Expected Calibration Error (ECE) and improves probability reliability. The DMSS ranks volumetric floods as the most severe attacks, and sensitivity analysis shows stable policy thresholds across operating points. The resulting 3rd Generation Partnership Project (3GPP)-aligned framework supports closed-loop mitigation and explicit control of the trade-off between security coverage and operational safety in 5G/Beyond 5G (B5G) networks.

A Smart City (SC) is a viable solution for green and sustainable living, especially with the current explosion in global population and rural-urban immigration. One of the fields that is not getting much attention in the Smart Economy (SE) is customer satisfaction. The SE is a component of SC that is concerned with using Information and Communication Technology (ICT) to improve stages of the traditional economy. In this paper, we propose a fog computing-based shopping recommendation system. Our simulations used Al-Madinah city as a case study. It aims to improve the customer shopping experience. Customers in shopping malls can connect to the system via Wi-Fi. Then the system recommends products to the shoppers according to their preferences. It optimizes shoppers' schedules using price, the distance between the shops, and the congestion. It also improves customers' savings by up to 30%. It also increases the shopping speed by up to 6.12% compared to the system proposed in the literature.

Routing discovery is a pivotal component of the communication stack in low-power and lossy networks (LLNs). The IPv6 routing protocol for LLNs, termed RPL, has been recently standardized to provide routing discovery in a wide range of LLN-based deployments realizing the Internet-of-Things (IoT) vision. RPL was mainly designed with the assumption that the predominant traffic flow would be gathering data toward a single destination, typically the root node. However, node-to-node (N2N) communication, where the root is neither a source nor destination, is a prime requirement in most of the LLN-based applications, such as actuating, decision making, and controlling applications. RPL in its current form does not cater well to such applications where there is a good number of inward N2N traffic flows. In this article, we propose a hybrid routing mechanism based on RPL for high N2N communications in LLNs referred to by HRPL. HRPL is implemented on Contiki and evaluated through extensive simulations on Cooja. HRPL is fully backward compatible with RPL where HRPL and RPL nodes can work together seamlessly in a hybrid network. Results show that HRPL provides a considerable improvement in the packet delivery ratio relative to the standardized RPL-based modes and to the RPL-based opportunistic routing approach. While HRPL requires a slightly larger memory footprint more than that for RPL, HRPL manages to significantly reduce the control plane packets, number of hops, and MAC transmissions needed to successfully deliver N2N data packets. Accordingly, this is translated to lower packet delay and less energy consumption.

Wireless sensor networks (WSNs) are mainly data-driven networks adopted to improve the Internet of Things (IoT) in terms of data throughput, energy efficiency, and self-management. Improving the data lifespan of WSN impacts the performance of the IoT. Achieving data reliability in applications of WSNs deployed in harsh environments is challenging due to the extreme constraints in resources of sensor nodes (SNs). Motivated by the inexpensive infrastructure of WSNs, a number of distributed storage systems have been proposed focusing on achieving data survivability rather than network reliability. In this article, we focus on data storage at the things layer (wireless sensors). We evaluate the performance of a number of distributed data storage systems (DDSSs) over WSN running over the ZigBee MAC protocol. Based on our findings, we introduce a new efficient-energy data dissemination scheme called data survivability with energy efficiency (DSwEE) that outperforms the existing schemes. We compare DSwEE against two prominent protocols in data storage, namely, decentralized erasure code for data survivability (DEC-DS) and decentralized erasure code encode-and-disseminate (DEC-EaD). Results show that DSwEE achieves better performance than both DEC-DS and DEC-EaD in terms of the energy consumption and data recoverability for localized failures, which improves the lifespan of the network.

Localization awareness is a fundamental requirement in many Internet of Things (IoT) and other wireless sensor applications. The information transmitted by an individual entity or node is of limited use without the knowledge of its location. Research in this area is mostly geared towards multi-hop range-free localization algorithm as that only utilizes connectivity (neighbors) information. This work focuses on anchor-based, range-free localization algorithm, particularly in anisotropic networks. We observe that the pioneer Distance Vector Hop or DV-Hop algorithm, which provides accurate estimation in isotropic networks, can be enhanced to compute localization estimation for anisotropic networks with similar or comparable accuracy. The recently proposed algorithms for anisotropic networks are complex with communication and computational overheads. These algorithms may also be overkill for several location dependent protocols and applications. This paper proposes a scheme, called DV-maxHop, which reaches comparable accuracy quickly utilizing simpler, practical and proven variant of the DV-Hop algorithm. We evaluate the performance of our scheme using extensive simulation on several topologies under the effect of multiple anisotropic factors such as the existence of obstacles, sparse and non-uniform sensor distribution, and irregular radio propagation pattern. Even for isotropic networks, our scheme out-performed recent algorithms with lower computational overheads as well as reduced energy or communication cost due to its faster convergence. We also introduce the formulation and simulation of Multi-objective Optimization to obtain the optimal solution.

Energy efficiency in specific clustering protocols is highly desired in wireless sensor networks. Most existing clustering protocols periodically form clusters and statically assign cluster heads (CHs) and thus are not energy efficient. Every non-CH node of these protocols sends data to the CH in every time slot of a frame allocated to them using the time division multiple access scheme, which is an energy-consuming process. Moreover, these protocols do not provide any fault tolerance mechanism. Considering these limitations, we have proposed an efficient fault-tolerant and energy-efficient clustering protocol for a wireless sensor network. The performance of the proposed protocol was tested by means of a simulation and compared against the low energy adaptive clustering hierarchy and dynamic static clustering protocols. Simulation results showed that the fault-tolerant and energy-efficient clustering protocol has better performance than both the low energy adaptive clustering hierarchy and dynamic static clustering protocols in terms of energy efficiency and reliability. Copyright © 2012 John Wiley & Sons, Ltd.

Wireless Sensor Networks (WSNs) consume a lot of energy in infrastructure creation and maintenance which also include topology control, i.e., coverage and connectivity. Several sleep-based topology control protocols have been proposed for better performance. While the existing protocols serve their purpose, they still consume high energy. We propose an energy-efficient protocol for Coverage, Connectivity and Communication (C3) in WSNs. The proposed protocol runs in four steps: divide the network into virtual rings using RSSI, define clusters having cluster heads at alternating rings, make dings that are rings inside clusters using triangular tessellation, and start sending data through cluster heads which may involve gateways. It achieves better performance by using near-optimal deployment, load balancing, and energy-efficient communication. Simulation results show that C3 protocol can guarantee 1-connected network, partial coverage of greater than 90% and energy-efficient communication, while consuming 20-25% energy compared to the Layered Diffusion-based Coverage Control (LDCC), and the Coverage and Connectivity Protocol (CCP).

Time synchronization plays an important role in distributed systems. Distributed wireless sensor networks (WSN) often require accurate time synchronization for coordination and data reliability. But precision of time synchronization is limited to scope and criticality of the application. Energy, lifetime and time synchronization are important parameters of any wireless sensor network. Flooding Time Synchronization Protocol (FTSP) and Recursive Time Synchronization Protocol (RTSP) are two state of the art protocols for time synchronization in WSNs. In this paper, a comparative analysis of both protocols under two different topologies i.e. bus and tree, using message count as performance parameter. Xbee Pro and Arduino Mega are used for communication and logical design implementation of both protocols, respectively.

Sand and dust storms (SDSs) offer very serious hazards to the environment, economy and health. An early warning of the upcoming SDS would allow people to take precautionary measures. Traditionally, satellite imaging is used to detect large-scale and long-term SDSs. However, small-scale and short-term SDSs may go undetected due to the poor spatial and temporal resolution of satellites. We propose a hybrid design of sand and dust storm detection system (SDSDS) using wireless sensor network (WSN) and satellite imaging in order to detect SDSs of all types. A layered architecture of context-aware system is used. While the WSN provides real time data from the area of interest, near-real time METEOSAT MSG images are obtained from their website. An experimental prototype is developed for evaluation of the proposed system. Performance studies show that such a hybrid approach can effectively detect and predict SDSs of all types.

There has been a tremendous growth in the use of wireless networks on Saudi Arabian highways, especially in the eastern region, which are subject to several sandstorms and sand dunes that yield to reduced visibility, unsafe roads and sometimes it is life threatening. This makes wireless sensor networks (WSNs) bring very promising, desired and effective natural solution to provide safe roads. This paper presents an agent-based system architecture approach for data dissemination in a WSN for sandstorm monitoring. This system architecture consists of three layers of agents, including the interface, routing and data collection layer. The interface agent interacts with the users to fulfill their interests, whereas the data collection layer has direct access to sensor nodes. The routing agent generates the optimized query plan to the cluster agent, performs data dissemination and efficient in-network processing with the other agents at the routing layer, and captures the required data through the data collection layer. This paper provides the agents' architecture, design and implementations that enable them to communicate and work together to disseminate and gather data in WSNs.

Over the past few years, with the trend of mobile computing, Mobile Ad hoc Network (MANET) has become one of the most important wireless communication mechanisms among all. Unlike traditional network, MANET does not have a fixed infrastructure, every single node in the network works as both a receiver and a transmitter. Nodes directly communicate with each other when they are both within their communication ranges. Otherwise, they rely on their neighbors to store and forward packets. As MANET does not require any fixed infrastructure and it is capable of self configuring, these unique characteristics made MANET ideal to be deployed in a remote or mission critical area like military use or remote exploration. However, the open medium and wide distribution of nodes in MANET leave it vulnerable to various means of attacks. It is crucial to develop suitable intrusion detection scheme to protect MANET from malicious attackers. In our previous research, we have proposed a mechanism called Enhanced Adaptive Acknowledgement (EAACK) scheme. Nevertheless, it suffers from the threat that it fails to detect misbehaving node when the attackers are smart enough to forge the acknowledgement packets. In this paper, we introduce Digital Signature Algorithm (DSA) into the EAACK scheme, and investigate the performance of DSA in MANET. The purpose of this paper is to present an improved version of EAACK called EAACK2 that performs better in the presence of false misbehavior and partial dropping.

A Mobile Ad-hoc NETwork (MANET) is an infrastructureless network consisting of self-configuring mobile nodes connected by wireless links. Nodes rely on each other to store and forward packets. Most of the proposed MANET protocols assume cooperative and friendly network context, and do not address security issues. Furthermore, MANETs are highly vulnerable for passive and active attacks because of their open medium, rapidly changing topology, lack of centralized monitoring. Encryption and authentication solutions, which are considered as the first line of defense, are not sufficient to protect MANETs from packet dropping attacks. Most of the current Intrusion Detection Systems (IDSs) for MANETS rely on the Watchdog technique. In this research we study the behavior of this technique and propose a novel mechanism, named: Adaptive ACKnowledgment (AACK), for solving two significant problems: the limited transmission power and receiver collision. This mechanism is an enhancement to the TWOACK scheme where its detection overhead is reduced while the detection efficiency is increased. NS2 is used to simulate and evaluate the proposed scheme and compare it against the TWOACK and Watchdog methods. The obtained results show that the new AACK scheme outperforms both of the TWOACK and Watchdog methods in terms of network packet delivery ratio and routing overhead.

There has been a tremendous growth in the use of wireless communication in the past few decades. Mobile Ad hoc NETwork (MANET) is one of the most important one among various wireless communication mechanisms. In MANET, each node in a network performs as both a transmitter and a receiver. They rely on each other to store and forward packets. Its unique infrastructureless network and self-configuring capability makes it ideal for many mission critical applications, including military use and remote exploration. However, these characteristics also make MANET vulnerable to passive and active attacks due to its open medium, changing topology and lack of centralized monitoring. To address the new security challenges, Intrusion Detection System (IDS) is required to detect the malicious attackers before they can accomplish any significant damages to the network. Many existing IDSs for MANETs are based upon Watchdog mechanism. In this paper, we propose a new IDS called Enhanced Adaptive ACKnowledgement (EAACK) that solves four significant problems of Watchdog mechanism, which are ambiguous collisions, receiver collisions, limited transmission power and false misbehavior report. We use Network Simulator 2 to simulate the proposed mechanism and compare the results with existing mechanisms.

The 3rd Generation Partnership Project (3GPP) has adopted an interworking architecture between Universal Mobile Telecommunication System (UMTS) and Wireless Local Area Networks (WLANs). This architecture imposes a set of security requirements on subscribers connecting from within interworked WLANs to be able to access their 3G home packet-switched services. Providing seamless handoff and session continuity of ongoing communication is a critical task in UMTS/WLAN integrated networks. However, the 3GPP does not specify how mobility can be supported. This paper provides a performance evaluation for the three candidate solutions: Mobile IP (MIP), Session Initiation Protocol (SIP), and mobile Stream Control Transmission Protocol (mSCTP) that may be used to provide session continuity in the integrated network. The vertical handoff delay figure is analyzed using simulations for different WLAN speeds and its major components due to the involved signaling procedures are quantified. The results are derived from our developed OPNET based simulation model that accounts for the detailed prescribed signaling procedures as per the related standards and Request for Comments (RFCs) documents, and the main network entities in the adopted architecture. The presented analysis provides insight into the potential performance bottlenecks in the integrated network. Major findings of the work show that the security related signaling and the signaling pertaining to obtaining a new Internet Protocol (IP) address, each contribute about 40% of the total delay for all the three solutions. Enhancements targeting these procedures will help reduce the overall delay while supporting seamless handoff between the two networks.

It is generally hard to find the optimal solution for sub-channel and power allocation for a multiuser Orthogonal Frequency Division Multiplexing (OFDM) system that maximizes the overall system capacity given the proportional rate constraint. Most existing solutions either utilize a suboptimal sub-channel allocation and attempt to compute the optimal power allocation or assume uniform power distribution among sub-channels and attempt to optimize using the sub-channel allocation. It is observed that derived solutions do not necessarily satisfy the proportional rate constraint, also referred to as the fairness constraint, supplied in the problem formulation. This paper proposes an iterative algorithm that computes the optimal power allocation for a given sub-channel allocation scheme. Unlike previous solutions, the proposed solution does not make any assumptions regarding the channels or regarding the proportionality constants. Furthermore, the proposed solution satisfies the proportional rate constraint in the strictest sense and therefore can provide absolute or hard rate guarantees as opposed to soft ones as the case for previous algorithms. Presented numerical example, shows that the our algorithm outperforms the original optimal power allocation algorithm and achieves strict satisfaction of the fairness constraint.

Shrinking size and increasing deployment density of wireless sensor nodes implies to smaller equipped battery size. This means emerging wireless sensor nodes must compete for efficient energy utilization. MAC protocols play a vital role in energy consumption of sensor node as it controls the radio activities. Customized or open source simulators play an important role to measure the performance effectiveness of MAC protocols. Due to the fact that they are flexible, reduce experimental overhead and cost. Nevertheless, these benefits come at the cost of results accuracy. In this paper, we investigate differences of the behaviour of our agent based S-MAC protocols in real deployment compared to the results produced using our custom based simulator, which ignores the lower layers effects such as packet collision and overhearing and using an ns2, an open source simulator, which provides a complete protocol stack. We further try to find and explain the rationale of the variance of results produced by real deployment and that of simulators.

Nowadays, wireless sensor networks are deployed in a wide range of applications such as military. To enable sinks to avoid physical attacks from adversaries, most of WSNs adopt sink-location privacy mechanisms. By utilizing these mechanisms, an adversary cannot analyze packet traffic and perform hop-by-hop trace-back, and thus deduce the location of a sink. In this paper, we propose an attack approach to track anonymous sinks. It utilizes a Pseudo-Noise (PN) code to mark a data flow in an invisible manner. An adversary is able to interfere with a source nodepsilas traffic by embedding a secure signal into the nodepsilas traffic. The signal is carried along with the traffic from the source node to the sink. Therefore, the attacker can recognize the location of a sink node by tracking the invisible secure signal. Through our simulation experiments, we conclude that the proposed attack approach is able to track an anonymous sink without additional traffic overhead.

Energy efficiency in the clustering protocols in highly desired in Wireless Sensor Network (WSN). The Dynamic Static Clustering (DSC) protocol is an energy efficient clustering protocol; however, it does not provide any fault tolerance mechanism. Moreover, the non-Cluster Head nodes send data to the Cluster Heads (CH) in every time slot of a frame allocated to them using TDMA scheme, which is an energy consuming process. Considering these limitations of the DSC protocol, we have proposed a more energy efficient and fault tolerant Dynamic Static Clustering (FT-DSC) protocol of WSN to enhance the performance of DSC. The performance of the proposal protocol has been tested by means of simulation and compared against the original DSC protocol. Simulation results show that the FT-DSC protocol has better performance than the DSC protocol in terms of energy efficiency and reliability.

An embedded sensor network is a system of nodes, each of which is equipped with a certain amount of sensing, actuating, computation, communication and storage components. Two major components of sensor nodes are sensing unit and wireless transceiver. They directly interact with nodes in wireless sensor networks (WSNs) that are easily prone to failure due to hardware failure, communication link errors, energy depletion, malicious attacks, etc. Even if the sensor node hardware is in excellent condition, still the communication between sensor nodes depends on many factors such as signal strength, obstacles and interference. Degradation in these factors results in low reliability of sensor nodes. One of the key prerequisite for an effective, efficient embedded sensor network is utilization of low-cost, low-overhead and high-resilient fault-inference techniques. Our attempt is to address fault-inference issues in sensor networks using an agent-based approach. Our proposed approach involves an intelligent agent that outfitted with a fault-inference engine. This engine profits from Expectation Maximization (EM) algorithm to evaluate fault probabilities of sensor nodes. Our experiment in a wireless sensor testbed is conducted to demonstrate the correctness and effectiveness of our approach.

Radio Frequency Identification (RFID) is becoming attractive technology as an alternative to barcode systems. RFID systems provide an automatic identification method, relying on storing and remotely retrieving data using RFID tags or transponders. An RFID tag is an object that can be attached to or incorporated into a product, animal, or person for the purpose of identification using radio waves. Chip-based RFID tags contain silicon chips and antennae. In this paper, we develop a smart shopping system that allows customers to manage their shopping list while shopping and only pay the bill at the checkout counter. The shopping cart has the ability to automatically calculate and display the total prices of all the products inside it. This makes it easy for the customer to know how much he or she has to pay while shopping and not at the checkout counter. This way the customer can also control his or her budget and receive faster service at the checkout. An advantage for the shop owners is that they would need a fewer cashiers, which would result in a large cut in their costs. In this paper, we also provide a mathematical model to calculate the estimated delay for each cart to access the system through the ad hoc or WLAN networks.

Implementing wireless sensor networks present new challenges compared with theoretical networks. In addition, results derived from the implementation might differ from theoretical results. Moreover, some routing protocols when implemented might fail to perform. In this paper, we implement three routing protocols namely: Dynamic MANET On-demand, Collection Tree and Dissemination Protocols using a TELOSB sensor network. Our aim is to compare their performances. To demonstrate the pros and cons of these protocols, several performance metrics are carried out. True sensors' readings are measured for future use in our simulation experiments.

Mobile IP is one of the popular mobility solution and a viable candidate for the Beyond 3rd Generation (B3G) networks such as the integrated 3rd Generation Universal Mobile Telecommunications System (UMTS) and the Wireless Local Area Networks (WLANs). Mobile IP has many configuration and enhancements that are proposed by IETF such as the Care-of-Address (CoA), Collocated CoA Mobile IPv6, and route optimizations. In this paper, we present a side-by-side performance evaluation and comparisons of the UMTS to WLAN handoff delay that results from using each configuration in the lately adopted UMTS/WLAN interworking architecture by 3GPP. In addition, we analyze the delay components due to 3GPP security and Internet protocol integration requirements. Simulation results show that under low network loading all configurations yield similar performances. However, Mobile IP with IPv6 configuration is more sensitive for network loads and wireless access speeds. In fact, it produces the highest delay figures at high load. Moreover, 3GPP security procedures contribute to more than 60% of the handoff delay for all the configurations.

The IEEE 802.11i amendment has been finalized to address the security issues in wireless local area networks. A prodigious amount of research has demonstrated that the IEEE 802.11i specification is sufficient to prevent unauthorized access and use. In this paper, we analyze the IEEE 802.11i wireless networking amendment with respect to data confidentiality, integrity, mutual authentication and availability. Our analysis indicates that a number of serious threats have still not been addressed by the 802.11i amendment. This includes DoS attacks, insider attacks, offline guessing attacks, etc. Furthermore, configuring security features on a commercial Wi-Fi network is moderately-to-very difficult. Towards this end, this paper proposes an improved authentication mechanism which adopts asymmetric cryptography and thus accomplishes link-layer frame protection. Through our further analysis and discussion, we conclude that the proposed mechanism not only prevents potential security threats but also accomplishes autonomic security configuration without human intervention.

The performance of wireless networks under video traffic is subjected to two-fold constraints. Both power minimization and other QoS requirements such delay, delay jitter etc. need to be taken care of properly. Mobile Ad Hoc Networks (MANETs) are more sensitive to these issues where each mobile device acts like a router and thus, routing delay adds significantly to overall end-to-end delay. In this paper, we analyze the performance of the Warning Energy Aware Clusterhead/Virtual Base Station-On demand (WEAC/VBS-O) protocol, proposed earlier by one of the authors [1], in terms of average delay, multihop communication and power minimization aspects subject to video traffic. The H.263 standard is utilized to model video traffic in our simulation design. Primarily, we establish a single hop communication between nodes. It is then extended to multihop communication. However, we found that the protocol can support up to two hops for an acceptable network performance provided there is a significant number of nodes in the network. Hence, we modelled the same network with H.264 and showed that the hop count increases from two to five with better performance. We also took power minimization issue into consideration and minimize power consumption by making use of HCB model by applying it within the neighborhood of the node. Simulation results showed that this strategy does minimize power consumption and it did not degrade multihop communication improvement. With the idea that maximum power saving is achieved if the relaying node lies in the middle of source and destination node for HCB model [2]. Furthermore, we saw the effect of sudden demise of cluster heads in the Warning Energy Aware Cluster head (WEAC) protocol based on our previous work [3]. Subsequently, we compared the results when some clusterheads (CHs) have sudden death to the results when there is no switching of CH based on selected performance metrics. We found that there is little power loss if the relaying node is not in the middle of source and destination node. However, performance is seriously degraded on the introduction of sudden demise of CH during simulation as far as average end-to-end delay is concerned.

Packet reservation multiple access (PRMA) can be considered as a merge of slotted ALOHA protocol and time division multiple access (TDMA) protocol. Independent terminals transmit packets to base station by contending to access an available time slots. A terminal that succeeds in reserving a certain time slot keeps on this reservation for transmitting its subsequent packets. Speech activity detection is used in PRMA to improve system capacity. In this work we propose a simpler contention mechanism that does not depend on a predetermined permission probability as in the original PRMA. In the new method, terminals select the contention slot uniformly from the pool of remaining free slots in the current frame. We evaluate the performance of the new contention mechanism in terms of various metrics including maximum number of carried voice calls and packet delays for a given acceptable drop rate of voice packets. We show that the new mechanism is superior to that of the original PRMA for loaded systems and is expected to be insensitive for traffic source burstiness.

Transporting video over wireless networks has twofold constraints. Not only should it satisfy delay requirements but power minimization and QoS issues should be handled carefully also. Mobile ad hoc networks (MANETs) are more sensitive to these issues where each mobile device acts like a router and thus, routing delay adds significantly to overall end-to-end delay. In this paper, we analyze the performance of the warning energy aware cluster head/virtual base station-on demand (WEAC/VBS-O) protocol, proposed earlier by one of the authors, in terms of average delay, multihop communication and power minimization aspects subject to video traffic. We use H.263 standard to model video traffic in our simulation design. Primarily, we establish a single hop communication between nodes. It is then extended to multihop communication. However, we find that the protocol can support up to 2 hops for an acceptable network performance provided there is a significant number of nodes in the network. We also take power minimization issue into consideration and minimize power consumption by making use of HCB model by applying it within the neighborhood of the node. Simulation results show that this strategy does minimize power consumption and it does not degrade multihop communication improvement. We finally show that the protocol is quite suitable for video traffic as it fulfils delay and other necessary requirements for a typical ad hoc network.

Increasing speed of hardware device and versatile functionalities of small equipments e.g. laptop, PDA etc. are introducing various voice oriented applications with mobility. Like other computer networks, in Mobile Ad-hoc Network (MANET) voice transmission is very much demanding and necessary. In this research paper we have a feasibility analysis of voice transmission over MANET. Since voice applications consume more energy than typical applications, we use an energy aware routing protocol known as WEAC for the study. We have a comparative study among several audio codecs (G. 711, G. 729 and G 723.1) and by simulation we show that the G 729 codec is suitable to use for voice transmission over MANET in terms of latency. We show that it is possible to launch voice transmission with acceptable quality over MANET using G 729 and WEAC protocol.

In current and next 3G and beyond mobile wireless systems, sharing the radio access network has become an important issue for 3G mobile operators. Sharing network infrastructure amongst operators offers an alternative solution to reduce the investment in the coverage phase of WCDMA, allows increased coverage, reduces time to market, and allows earlier user acceptance for WCDMA and its related services. In this paper a novel radio resource management strategy known as adaptive partitioning with borrowing (APB) is proposed to cope with the implied new architectural changes. This strategy is devoted to achieve an efficient usage of the available pool of radio resources while satisfying the required quality of service (QoS) in heterogeneous traffic 3G wireless networks. Grade of service (GoS) and resources utilization are considered in this study to evaluate the network performance. Simulation results indicate that the proposed APB resource allocation provides higher resource utilization under all load conditions leading in turn to increased revenue. Moreover it provides the best balance between the system utilization and the required QoS

Wireless mobile ad hoc networks depend on batteries or other fatiguing means for their energy. Power aware design and estimation of transmit power requires familiarity with the energy consumption behavior in wireless systems. Moreover, selection of gateways has not been introduced thoroughly. This paper introduces a mathematical analysis for power adjustment and then we use these equations in selecting gateways in the simulation experiments according to two different criteria: the gateway with the highest energy level and the gateway with the least number of neighbors

We introduce the virtual base station on-demand (VBS-O) routing protocol for wireless mobile ad hoc communications, which built on top of any mobile infrastructure protocol, the warning energy aware clusterhead (WEAC) infrastructure protocol. The WEAC protocol establishes a dynamic wireless mobile infrastructure to mimic the operation of the fixed infrastructure in cellular networks. In the WEAC protocol, a mobile station is elected from a set of nominees, based on its energy level, to act as a temporary base station within its zone. Mobile stations elected as VBSs are used to track other mobile stations in the ad hoc network. The VBS-O routing algorithm utilizes the mobility-tracking mechanism of the WEAC infrastructure creation protocol to route the packets. The VBS-O architecture complying with QoS guarantees imposes the use of a MAC method that guarantees the successful transmission of packets under high mobility and/or heavy load circumstances, and hence meets the QoS constraints dictated by the communications application.

In this paper, we propose a novel cluster-based infrastructure creation protocol, namely: warning energy aware clusterhead (WEAC). WEAC establishes a dynamic wireless mobile infrastructure. As in all cluster-based infrastructure protocols, in the WEAC protocol, a mobile node is elected from a set of nominees to act as a temporary base station for a period of time within its zone. We study the characteristics and performance of the WEAC protocol by means of simulation. It is shown that the WEAC protocol scales well to large networks of mobile stations, and it outperforms other routing energy saving amongst the network. The WEAC protocol would facilitate the development of a comprehensive and promising framework for quality of service (QoS) management in wireless mobile ad hoc networks once the proper integration of the MAC protocol with the routing and call admission control mechanisms is established. At that time, it would lay the groundwork for assigning bandwidth, and/or implementing priorities, and hence for QoS-based routing by conveying the quality of a path prior to call setup.