In next-generation vehicular networks (5G/6G), efficiently offloading computationally intensive tasks to edge/cloud servers is critical to ensuring low latency and scalable service delivery. However, existing solutions often overlook the revenue concerns of service providers and rely on static, region-limited load balancing. In this paper, we propose ReLoad, a Deep Reinforcement Learning (DRL)-based task offloading framework that jointly maximizes service provider revenue and ensures dynamic load balancing. Our scheme leverages cloud-managed, resource-aware clustering of edge servers, allowing adaptive workload distribution even under heavy traffic fluctuations. Within each cluster, a DRL agent with attention-based feature extraction decides whether to offload tasks to an edge server or the cloud, thereby balancing computation costs, communication overhead, and user payments. Simulation results show that ReLoad achieves up to 10% higher task success rates and 20% greater profitability compared to existing approaches, demonstrating its effectiveness in real-time vehicular offloading for 5G/6G edge environments.

Safety services of Vehicular Ad Hoc Network (VANET) require reliable broadcasts. We propose a reliable broadcast mechanism for urban roads called VANET Broadcasting for Urban areas based on Road Layout (VBURL), which tries to minimize the dependency on information that may become inaccurate to maximize the efficiency of broadcast. Specifically, the proposed mechanism takes into account the road layout information accessible from the digital map and only the real‐time information obtained from the broadcast messages or beacons. VBURL basically makes the vehicle that is farthest from the current forwarding vehicle take the role of next forwarding vehicle and, if possible, makes an additional broadcast happen at the intersections where the effect of signal attenuation caused by the road side obstacles is low in order to have prompt and reliable dissemination of safety messages towards all roads connected to the intersections. The simulation results verified that VBURL achieves the same high performance as that of the compared legacy schemes in terms of reliability with much higher efficiency. Even though the message reception delay of VBURL is slightly longer than those of compared schemes, it is far less significant to impair the original purpose of safety message.

Wireless sensor networks (WSNs) serving in hostile environments are susceptible to multiple collocated failures due to explosives and natural calamities such as avalanches, landslides, etc., which can partition the network into disjoint segments. In such a scenario, federating the segments becomes essential for reestablishing communication among segments and resuming the WSN operation. Placing relays has been a popular strategy for forming a connected inter-segment topology. In this paper, we tackle the federation problem while considering constrained relay availability. We exploit the use of a limited number of mobile relays to provide intermittent inter-segment connectivity. We propose FLOWER, a novel algorithm for Federation with LOW inter-segment latency and Even Relay load. FLOWER groups the segments into clusters and forms a star inter-cluster topology where each cluster is served by a distinct mobile relay. A cluster at the center of the area serves as a hub to bound inter-segment communication delay. In addition, FLOWER opts to prolong the lifetime of the mobile relays by balancing the energy overhead due to travel and wireless communication. We validate its performance through extensive simulation experiments.

In today's Internet, New Reno is the most widely deployed connection oriented transport layer protocol. However, the performance of New Reno degrades significantly when New Reno operates in Multi-hop Wireless Networks (MWNs). Frequent retransmission timeouts, which is one of the well-known problems of the performance degradation of New Reno over MWNs. In MWNs, retransmission timeout is unavoidable when multiple packets are lost from one window of data during fast recovery. In this paper, we propose a sender side algorithm, called SRA (Sudden Recovery Algorithm) for handling retransmission timeouts due to the multiple losses of newly sent packets during fast recovery and thereby improve the performance of New Reno over MWNs. Simulation results show that SRA achieves significant improvements in throughput than current TCP versions especially when retransmission timeouts happens during fast recovery.

Reliability as well as efficiency of transmissions is of a paramount issue for the safety critical services of VANET due to the urgency and/or significance of the messages. To this end,various retransmission mechanisms have been studied for reliable broadcast message delivery in VANETs. Most of the existing approaches, though, rely on periodic beacons for retransmission decisions and intrinsically require high control overheads. Especially, in urban environments where the traffic density tends to be high, minimizing control overheads is important not only for the efficiency but also for the reliability of user message delivery. In this paper, we propose an efficient broadcast message delivery mechanism, which does not rely on the periodic beacon exchanges. Based on the observation that the broadcast message delivery could be particularly difficult at the intersections due to the signal diffraction and attenuation caused by the obstacles such as buildings around the corners of the intersection, a novel mechanism to make efficient and effective retransmissions across an intersection is proposed. Simulation results show that the proposed mechanism can provide similar or better reliability while incurring prominently less overheads than the existing approaches.

Location service can be used to provide location information of vehicles for various applications including the position-based routing protocols in vehicular ad-hoc networks (VANET). The performance and the overhead of location service in VANET largely depends on the mechanisms to assign the vehicles to the location servers. Utilizing hash functions to determine the location server of a vehicle allows the mapping between the server and the vehicle to last long, and also enables even distribution of vehicles to the available servers. However, the geographical proximity of the vehicles and the servers is hard to be taken into account. On the other hand, the region based approaches divide the geographical area into subdivisions and assign local servers to the vehicles. Due to the high mobility of vehicles, though, the mapping between the servers and the vehicles changes frequently. We propose a dynamic mobile group based location service management (MG-LSM) mechanism, which dynamically groups the vehicles running nearby according to their moving direction with one of the vehicles in the group taking the role of location server. Since the location server is moving together with the vehicles receiving the service, geographical proximity between the location server and the vehicles can be maintained while the mapping between the location servers and the vehicles lasts long due to the characteristics of VANET mobility, i.e., majority of the vehicles running on the same road segment move with a similar velocity maintaining the proximity for a while. Through a simulation, the performance of the MG-LSM is compared with an existing approach. The simulation results show that the MG-LSM provides more accurate location discovery service with lower overhead.

With the advance of various wireless access technologies, the demand for a mobile user equipped with multiple air interfaces simultaneously executing diverse applications emerged. In such network environment, per- application mobility management is a key to allow each application of an end user device to dynamically and fully take advantage of the most suitable access technology. In this paper, we devised a comprehensive architectural platform with cross- layer techniques to realize this disruptive technology, i.e., per- application mobility management. Four core functional modules composing the proposed platform for end user devices are defined: Monitoring Agents, Profile Database, Decision Engine, and IP Agent. We show through simulations that the presented platform provides an improved QoS as it selectively utilizes the best available networks depending on different QoS constraints of different applications.

In this paper, we propose a wireless network domain structure which deploys a special cell, called a gray cell. The boundaries of wireless network regions are surrounded by the gray cells, and the gray cells are supposed to belong to all of its neighboring regions. Based on this wireless domain structure, we propose a mechanism which completely removes the waste of redundant resource reservation in the wireless network domain while greatly reducing the risk of reservation disruption caused by inter-region handovers. Using simulation, it is shown that the proposed mechanism can deal with inter-region handover as effectively as it does with intra-region handover. It is also shown that the proposed mechanism outperforms existing mechanisms with respect to reservation disruption time and packet losses caused by handovers.

In order to provide continuous QoS guarantees to a mobile user, it is required to deploy a mechanism which reserves resources in advance at the locations to which the mobile user is expected to move. An important issue with regards to these mechanisms is to minimize the waste of resources caused by redundant reservations while keeping up the QoS services to the user. In this paper, we propose a wireless network domain structure which deploys a special cell, called a gray cell. The boundaries of wireless network regions are surrounded by the gray cells, and the gray cells are supposed to belong to all of their neighboring regions. Based on this structure, we propose a mechanism which completely removes the waste of redundant resource reservation while greatly reducing the risk of reservation disruption caused by inter-region handovers. Using simulation, it is shown that the proposed mechanism can deal with inter-region handover as effectively as it does with intra-region handover. It is also presented that the proposed mechanism outperforms existing mechanisms with respect to reservation disruption time and packet losses caused by handovers.

This paper proposes a new QoS framework, called the on-demand QoS path framework (ODP). ODP provides end-to-end QoS guarantees to individual flows with minimal overhead, while keeping the scalability characteristic of Diff-Serv. ODP exercises per-flow admission control and end-to-end bandwidth reservation at the edge of the network and only differentiates traffic classes in the core of the network. In addition, to adapt to dynamically changing traffic load, ODP monitors the bandwidth utilization of the network and performs dynamic bandwidth reconfiguration in the network core. Through extensive simulations, the performance of ODP is investigated and compared with that of IntServ and DiffServ frameworks. The simulation results clearly show that ODP provides end-to-end QoS guarantees to individual flows, which DiffServ can not provide, with much less overhead than IntServ.

Supporting transmission of stream media over wireless mobile networks is often difficult because packets may be lost due to the rerouting of packets during handoff, and also because bursts of packet loss may occur during handoff due to the disparity in the amount of available bandwidth among different cells. In this paper, we propose an end-to-end multipath handoff scheme that provides smooth handoff for stream media in wireless networks with different amounts of available bandwidth from cell to cell. In the proposed scheme, multiple paths are established during handoff to reach a mobile destination node. The stream media sources are equipped with an adaptive multilayer encoder, and important layers in the encoded video stream are duplicated and transmitted over multiple paths during handoff. The effectiveness of the proposed multipath handoff scheme is verified and compared with existing schemes through extensive simulations. The simulation results show that the proposed scheme provides higher throughput and better quality for stream media.

The emergence of multiprotocol label switching (MPLS) with its efficient support of explicit routing provides basic mechanisms for facilitating traffic engineering. Exploiting this capability of MPLS, we propose an adaptive multipath traffic engineering mechanism named LDM (load distribution over multipath). The main goal of LDM is to enhance the network utilization as well as the network performance by adaptively splitting traffic load among multiple paths. LDM takes pure dynamic approach not requiring any a priori traffic load statistics. Routing decisions are made at the flow level, and traffic proportioning reflects both the length and the load of a path. LDM also dynamically selects a few good label switched paths (LSPs) according to the state of the entire network. We use simulation to compare the performance of LDM with the performance of several representative dynamic load distribution approaches as well as the traditional static shortest path only routing. The numerical results show that LDM outperforms the compared approaches in both the blocking ratio as well as the performance of the accepted traffic flows.

We propose centralized server based QoS routing schemes, where a route server is responsible for determining QoS paths on behalf of all the routers in a routing domain. In the proposed server based schemes, the dynamic link QoS state information, which is required for a QoS path computation, is implicitly maintained at the route server as it assigns or gets back QoS paths. By maintaining the network state information this way, we may not only eliminate the overhead to exchange network state update messages but also achieve higher routing performance by utilizing accurate network state information in the path computation. We discuss path caching techniques for reducing the amount of path computation overhead at the route server, and evaluate the performance of the proposed schemes using simulation. The simulation results show that the path caching schemes may significantly reduce the route server load. The proposed schemes are also compared to the distributed QoS routing schemes proposed in the literature. It has been shown that the proposed server based schemes not only enhance the routing performance, but they are also competitive with respect to routing overheads.

While existing research shows that reactive congestion control mechanisms are capable of providing high video quality and channel utilization for point-to-point real-time video, there has been relatively little study of the reactive congestion control of point-to-multipoint video, especially in ATM networks. Problems complicating the provision of multipoint, feedback-based real-time video service include: (1) implosion of feedback returning to the source as the number of multicast destinations increases and (2) variance in the amount of available bandwidth on different branches in the multipoint connection. A new service architecture is proposed for real-time multicast video, and two multipoint feedback mechanisms to support this service are introduced and studied. The mechanisms support a minimum bandwidth guarantee and the best effort support of video traffic exceeding the minimum rate. They both rely on adaptive, multilayered coding at the video source and closed-loop feedback from the network in order to control both the high and low priority video generation rates of the video encoder. Simulation results show that the studied feedback mechanisms provide, at the minimum, a quality of video comparable to a constant bit rate (CBR) connection reserving the same amount of bandwidth. When unutilized network bandwidth becomes available, the mechanisms are capable of exploiting it to dynamically improve video quality beyond the minimum guaranteed level.