Hop Link Research Articles

Dynamic Traffic Grooming Based on Virtualization-Plane-Aided Optimization for Elastic Optical Satellite Networks

With the increase in global wireless traffic, the use of large-scale satellite networking to provide ubiquitous access is one of the essential trends of future 6G network development. Elastic optical satellite networks (EOSNs) are widely considered a flexible solution for future satellite communication. However, with the continuous proliferation of network devices and users, the growing disparity between user demands and the limited bandwidth and capacity of the network is becoming increasingly noticeable. This has led to issues such as constrained network resource utilization and resource fragmentation. Therefore, EOSNs must efficiently address the challenge of allocating scarce bandwidth resources. Effective traffic grooming methods will be applied to EOSNs to solve the problem of bandwidth shortage. This paper proposed a dynamic traffic grooming algorithm based on virtualization-plane-aided optimization (DTG-VPO) to facilitate the bandwidth allocation for EOSNs. Firstly, the nodes of the alternative paths were graded, and the weights of the subsequent hop links were modified. Then, the path was evaluated using link weights, alternative paths were selected in the virtual and physical topologies, respectively, and a path set was constructed. Finally, a resource block evaluation parameter was designed to quantify the quality of candidate resource blocks and rank them. A series of simulations have evaluated the traffic-blocking probability and wavelength utilization under different traffic loads. The link resource was more fully utilized compared with other traffic grooming algorithms. The blocking probability can be reduced by 75%, while wavelength utilization can be improved by 8.1%.

An improved RPL algorithm for low-power and lossy networks

The routing protocol for low-power and lossy networks (RPL), standardized by Internet Engineering Task Force (IETF), is mainly designed to use for Low-power and Lossy Networks (LLNs). To solve the problems of several important routing metrics are not evaluated, the optimal path may contain long single hop links, lack of scientific multi-routing metrics evaluation method and mechanism to balance the parent child number (especially the parent with one hop away from root), this paper proposes an improved RPL algorithm for LLN (I-RPL). First of all, we propose the evaluated routing metrics: child number of parent, candidate parent number, hop count, ETX and energy consumption index. Meanwhile, we improve the path ETX calculation method to avoid selecting optimal path containing long single hop links. Then we design a novel lexical method to synthetically evaluate candidate parents. Meanwhile, based on the evaluation results of candidate parents, we design a novel objective function and a new calculation node rank method which can also be used for selecting the optimal path. Finally, evaluation results show that I-RPL outperforms ETXOF and several other improvements in terms of packet delivery ratio, latency, etc.

Design of a Novel Wireless NoC Architecture for Chip Multiprocessor

The Network on chip is a new communication method of System on Chip. It is the main part of multi-core technology. A large number of embedded cores can be combined on a single chip. Due to the multi-hop characteristics of communication, there are some problems in the design of traditional NoC, such as high latency and power consumption. Thus, to handle the communication problem of long-distance transmission of traditional NoC, wireless Networks on Chip (WiNoC) has been proposed. Using WiNoC to design the multi-core System on Chip can significantly reduce the latency and energy consumption of the network. The advantage of using wireless network on chip is to replace the multi-hop path of traditional network on chip with wireless single hop link. However, due to the limited space on the chip and the cost, it is very important to determine the optimal number and correct location of wireless hubs. In this paper, we propose a new method to obtain the optimum configuration of a WiNoC by using the Co-evolutionary Algorithms (CA) and a wireless NoC architecture based on mesh. This work examines the effect of VC and sub-net size on WiNoC performance efficiency and energy under different packet injection rate (PIR) and the number of cores (64, 144 and 256). The simulation experiment of the algorithm proposed in the whole architecture has been implemented on the Noxim platform.

Throughput Maximization of a UAV Assisted CR Network With NOMA-Based Communication and Energy-Harvesting

The performance of an unmanned aerial vehicle (UAV) assisted cooperative cognitive radio (CR) network is studied in this paper. The study is carried out for line-of-sight (LOS) links between UAV and a ground user and UAV aerodynamic power consumption of UAV. The UAV consists of an RF energy harvester and it is also a CR enabled device. It harvests energy from RF signal of source nodes. It rotates periodically over a circular region of interest (CROI) for finding the vacant primary user (PU) band. It uses a PU band to set a link between ground nodes, while the direct links between them suffer from severe fading. The decision about the status of a PU band is made cooperatively. In cooperative sensing, all the sources along with the UAV take sensing decisions and send them to fusion centre (FC). A two stage fusion scheme is proposed to take the overall decision. The considered network model uses non-orthogonal multiple access (NOMA) scheme to forward the information of a source to its corresponding destination. Analytical expressions of harvested energy, overall sensing decision and throughput are developed. The analytical expressions capture the effect of fading as well as change in distances (source-UAV and UAV-destination) due to the circular flight of the UAV. Impact of imperfect successive interference cancellation (SIC) on the system performance is also studied. Power allocation in the second hop link is optimized to maximize the network throughput. Energy-efficiency of the considered network is evaluated. For a given UAV flight period, radius of the circular trajectory, and the velocity of the UAV is optimized to maximize the energy-efficiency. Sensing performance of the considered system model is studied in terms of false alarm. Network throughput is investigated for several network parameters such as fading parameter, the number of sources, the number of UAV's sensing slots, the velocity of UAV, the radius of the UAV trajectory etc. Sensing angle and harvesting angle are optimized to maximize the throughput. Results show that the value of fading parameter, radius of UAV trajectory, and UAV velocity has significant impact on throughput. The performance of NOMA is compared with orthogonal multiple access (OMA).

Design o f Wireless Ad Hoc System u sing Adaptive Multi Hop Link State Optimal Routing Protocol

Now a days for the radio network communication multi-hop routing is used. This multi-hop routing technique covers larger coverage area. Therefore to reach at specific location data is transferred in form of packets from one node to other node. But for the transmission of radio signals over the large distance, large number of transreceivers are required and these transreceivers requires large power to operate. As a result, multi-hop routing can saves energy over separate routing. Therefore it is necessity to design a cost effective multi-hop routing technique for successful transmission of ratio packet data. In this paper a hop by hop adaptive link state optional routing (HALO) is explained. It is the first packet transmitting solution with hop by hop and link state routing, which reduces the cost of transporting data across a packet switch network[3]. The triple model is designed for multi hop packet routing. In this work each node of network iteratively and separately improves the small part of traffic bound. This algorithm finds the shortest path of specific location for every iteration and it is calculated by the marginal cost of the various links of network. The marginal link cost is used to calculate the shortest path between the node and the destination location. This marginal link cost is gathered from link state updates. The various networks changes are automatically identified by the adaptive method which is used in this paper. Due to this the exchange between the packets on wrong node is reduced over the overhead traffic. To validate these theoretical results the experimental evaluations and mathematical calculations are also reported in this work. Net beans java is the programmed use in this proposed project.

Link Stability Based Approach for Route Discovery in MANET Using DSR

Background: Mobile Ad-hoc network is a set of devices which are capable of communicating with each other without the help of any central entity or fixed infrastructure. The absence of fixed access points makes MANET flexible and deployable at the extreme geographical territories. Each device has routing capabilities to facilitate communication among nodes in the network. Objectives: 1) To selects the stable path which has lowest hop count. 2) To use backup path in case of link break up to minimize delay incurred in finding out the alternate path. Methods: Dynamic source routing is modified to choose the most stable path and a backup path is cached to save the route discovery time in case of link failure. Results: The modified-DSR based on Link stability and hop count is performing better as compared to DSR most of the time. Conclusion: A modified-DSR is proposed that selects the path using hop count and link stability as parameters. The advantage of modified-DSR is that if a link breaks in between data communication then back up path can be used for carrying out the data transfer. Analysis is done by varying the node density and counting number of packets received .Modified-DSR gives better results for light to moderate network and DSR performs better if the number of nodes increases beyond a certain limit.

Qos Improvement Using Hybrid Genetic Algorithm Based AODV In Manet

Multi hop links are used to communicate between nodes in a Mobile Ad Hoc Network (MANET). Data packets are routed through intermediate nodes in the network to the destination node since each node functions as a router. Dynamic routing protocols are being developed for network communication efficiency. Routing protocols in MANETS face problems such as versatility, scalability, and restricted bandwidth. A fuzzy logic approach is suggested as part of the study. In this work, a fuzzy logic methodology is planned to choose the best routes in order to better QoS End-to-end delay (Ae), when a node leaves the network (Nl), A fuzzy rule-based scheme NR includes the number of packets dropped (ND) and the number of path error RRER caused parameters. Simulations are carried out in this study using the proposed fuzzy approach process Simulations are carried out in this study using the future process fuzzy approach. The measurement criteria are throughput and the number of packets dropped. The tentative results obtained show that the proposed fuzzy approach improves the QoS better than existing regular Ad hoc On-demand Distance Vector ( AODV) routing protocol. In the final stage of investigation, the use of a hybrid optimization approach to choose the best route is suggested. The proposed hybrid optimization is based on the Genetic Algorithm (GA) and the Hill Climbing algorithm. The hybrid optimization aids in the resolution of the local minimum problem Hill-climbing begins with an infeasible solution and continues until a viable solution is found, at which point the viable solution is returned to GA. The simulation results show that the throughput is high. When compared to the AODV protocol, the proposed Fuzzy-Hybrid GA method yields about 29.56 percent more and 6.33 percent more when compared to the Fuzzy-GA solution.

V2V Routing in VANET Based on Heuristic Q-Learning

Designing efficient routing algorithms in vehicular ad hoc networks (VANETs) plays an important role in the emerging intelligent transportation systems. In this paper, a routing algorithm based on the improved Q-learning is proposed for vehicle-to-vehicle (V2V) communications in VANETs. Firstly, a link maintenance time model is established, and the maintenance time is taken as an important parameter in the design of routing algorithm to ensure the reliability of each hop link. Aiming at the low efficiency and slow convergence of Q-learning, heuristic function and evaluation function are introduced to accelerate the update of Q-value of current optimal action, reduce unnecessary exploration, accelerate the convergence speed of Q-learning process and improve learning efficiency. The learning task is dispersed in each vehicle node in the new routing algorithm and it maintains the reliable routing path by periodically exchanging beacon information with surrounding nodes, guides the node’s forwarding action by combining the delay information between nodes to improve the efficiency of data forwarding. The performance of the algorithm is evaluated by NS2 simulator. The results show that the algorithm has a good effect on the package delivery rate and end-to-end delay.

Design of Shrewd Underwater Routing Synergy Using Porous Energy Shells

During the course of ubiquitous data monitoring in the underwater environment, achieving sustainable communication links among the sensor nodes with astute link quality seems an ordeal challenge. Energy utilization has a direct impact because all active devices are battery dependent and no charging or replacement actions can be made when cost- effective data packet delivery has been set as the benchmark. Hop link inspection and the selection of a Shrewd link through a resurrecting link factor have been nothing short of a bleak challenge, and only possible after meticulous research to develop a shrewd underwater routing synergy using extra porous energy shells (SURS-PES) which has never been conducted before. After broadcasting packets, the sensor node conducts a link inspection phase, thereby, if any link is found to be less than or equal to 50% shaky, the destination receiving node adds its residual energy status and returns it to the source node which adds some unusable energy porous shell to strengthen the link from 5% to a maximum of 90% and sends it only to the targeted node, therefore, an unaltered data packet delivery is anticipated. Performance evaluation was carried out using an NS2 simulator and the obtained results were compared with depth-based routing (DBR) and energy efficient DBR (EEDBR) to observe the outcomes with results that confirmed the previously mentioned direction for research in this area.

Underwater Resurrection Routing Synergy using Astucious Energy Pods

The accomplishment of sustainable communication among source and destination sink node is a rigors challenge and even establishing bodacious communication link between these nodes is nothing short of a miracle because data routes are governed by the underwater environment. Energy consumption has a significant influence as all active devices rely on the battery. As cost-effective data packet transmission is established as a norm, no charging or replacement can be achieved. Hop link evaluation and shrewd connection discovery by way of a resurrecting linking element were just a genuinely grim task, and only feasible to create the extra powered energy pods (URR-SAEP) that had never been carried out before after detailed study. After packet transfer, the sensor node performs the link inspection process, and when a link is deemed shaky at less than or equivalent to 50 percent of capacity, the target node incorporates its residual capacity status and returns it to the source node that attaches other unoptimizable energy pods to improve only the targeted node link from 50 percent to 90 percent. Performance evaluation using NS2 with Aqua-Sim 2.0 simulator has been obtained comparing with DBR and EEDBR protocols in terms of point-to-point delay, Packet dissemination ratio, Network lifespan and Energy Diminution.

Design and Evaluation of “BTTN”: A Backscattering Tag-to-Tag Network

Radio frequency (RF)-powered backscatter communication between passive tags holds tremendous potential as an enabling technology for a ubiquitous “Internet of Things.” We develop a backscattering tag-to-tag network (BTTN), comprised of passive tags capable of large-scale, passive, and multihop communication with each other via backscatter modulation of an external RF excitation signal. The low sensitivity and lack of active demodulator on passive tags present significant challenges to the communication, including a unique phase cancellation problem, which significantly affects the range and robustness of a passive tag-to-tag link. We overcome these challenges using innovative tag architecture and also develop a novel multiphase backscatter modulation technique with a learning mechanism that overcomes the phase cancellation problem. This improves the link performance bringing passive tag-to-tag communication closer to practical use. The additional hardware compared to the conventional radio frequency identification tag architecture includes one more terminating impedance in the modulator. The data rate is reduced due to backscatter at two different phases while the increase in the power consumption is negligible. We develop prototype BTTN tag hardware and firmware and evaluate its performance. The prototype achieves link ranges of up to 3 m at 5 kb/s with an excitation power level of only -20 dBm while successfully overcoming phase cancellation. We further extend BTTN operation to a multihop network where we demonstrate a four hop link capable of communicating over 12 m under similar conditions.

A Stable Routing Algorithm for Mobile Ad Hoc Network Using Fuzzy Logic System

The mobile ad hoc network (MANET) is an infrastructure-less network, where the nodes communicate either directly or indirectly through intermediate nodes. The network topology can change frequently due to its dynamic nature and limited resource availability. In MANET energy-efficient routing is a major issue because nodes are operated with a limited battery power. The energy-efficient routing algorithm can confirm the high performance by increasing the network lifetime. In order to make the network more scalable, the routing algorithm needs to maximise the usage of network resources. This paper proposes a novel routing approach energy aware fuzzy controlled routing (EAFCR) algorithm. The proposed algorithm enriches the intelligence to the node by applying the fuzzy decision tools to develop a more stable and energy-efficient route during the route discovery phase. The fuzzy logic system uses the per hop delay, available energy and link quality to form a more stable route. With the proposed EAFCR algorithm, the packet delivery ratio, end-to-end delay, residual energy, and throughput show an improvement of 3.05%, 1.38%, 4.25% and 3.3% respectively, than the existing fuzzy logic modified AODV routing (FMAR) protocol.

Determination of Array Gain of Single Hop to Achieve the Performance of a 2-Hop Wireless Link

In adaptive beamforming system adaptive algorithm of digital filter is applied to update the weighting vector of the antenna elements to get antenna gain along the desired direction and attenuation along the jammer. The objective of the paper is to evaluate the threshold gain of the adaptive beam former along the line of sight (LOS) between the transmitter and the receiver (including jammer suppression) to make the single hop link comparable with 2-hop link. The single hop and 2-hop communication systems are compared in context of symbol error rate (SER) under fading condition theoretically and verified by simulation. Finally we evaluate the numerical value of threshold gain of adaptive beamformer of two antenna elements under Rayleigh and Nakagami-m fading conditions.

Effect of AQM-Based RLC Buffer Management on the eNB Scheduling Algorithm in LTE Network

With the advancement of the Long-Term Evolution (LTE) network and smart-phones, most of today’s internet content is delivered via cellular links. Due to the nature of wireless signal propagation, the capacity of the last hop link can vary within a short period of time. Unfortunately, Transmission Control Protocol (TCP) does not perform well in such scenarios, potentially leading to poor Quality of Service (QoS) (e.g., end-to-end throughput and delay) for the end user. In this work, we have studied the effect of Active Queue Management (AQM) based congestion control and intra LTE handover on the performance of different Medium Access Control (MAC) schedulers with TCP traffic by ns3 simulation. A proper AQM design in the Radio Link Control (RLC) buffer of eNB in the LTE network leads to the avoidance of forced drops and link under-utilization along with robustness to a variety of network traffic-loads. We first demonstrate that the original Random Early Detection (RED) linear dropping function cannot cope well with different traffic-load scenarios. Then, we establish a heuristic approach in which different non-linear functions are proposed with one parameter free to define. In our simulations, we demonstrate that the performance of different schedulers can be enhanced via proper dropping function.

Multi-criteria routing metric for supporting data-differentiated service in hybrid wireless mesh networks in coal mines

Mesh clients in hybrid wireless mesh networks can perform the routing functionality, as well as provide end-user applications that are more suitable for tunnels, to improve the connectivity of backbone networks. In this article, based on the diversity of data and limited power supply of mesh clients in hybrid wireless mesh networks in underground mines, we propose a multi-criteria routing metric to support data-differentiated service. This routing metric divides data into two types: urgent and non-urgent. End-to-end delay is calculated when transmitting urgent data, and hop count and link load are measured when transmitting non-urgent data. In order to optimize the utilization of mesh clients and to prolong the network lifetime, mesh clients and mesh routers are given different weights in the calculation of hop count. Based on the QualNet7.1 simulation platform, the performance of the proposed routing metric in transmitting urgent and non-urgent data is evaluated through numerous simulations. Simulation results indicate that the routes selected using the proposed routing metric can effectively reduce the average end-to-end delay when transmitting urgent data and reduce the utilization rate of mesh clients while simultaneously guaranteeing the capability of the network when transmitting non-urgent data. This finding satisfies the differentiated service requirements of data of different types for hybrid wireless mesh networks in coal mines.

An SRAM-based novel hardware architecture for longest prefix matching for IP route lookup

A static random access memory (SRAM)-based novel hardware architecture for longest prefix match (LPM) search scheme has been proposed in this paper. The key concept of this architecture is to store the IP prefixes virtually in the forwarding table. This architecture reduces memory consumption by using a two-tier hierarchical SRAM-based memory structure for maintaining the next hop port information. Originally, next hop addresses are kept in the shared global memory called next hop global memory (NHGM) and its links are maintained in another memory, called next hop link memory (NHLM). This approximately reduces memory consumption by 50---62.5% compared to existing SRAM-based schemes. The proposed architecture consumes single memory write cycle to store an IP prefix and also takes single memory read cycle for LPM search. However, finding next hop information incurs two memory read cycles due to hierarchical next hop memory structure. The proposed scheme performs an LPM lookup operation in 1.05---1.31 ns in IPv4 and between 1.05 and 1.6 ns in IPv6. This results into LPM search throughput of 950 million lookups per second (MLPS) to 760 MLPS in IPv4 and between 620 and 950 MLPS in IPv6. The average search throughput achievable from this architecture is roughly 850 MLPS in IPv4 and 780 MLPS in IPv6. The numerical results show that this architecture significantly reduces memory requirement, power consumption, and transistor-count/bit requirement.

Efficient Resource Scheduling by Exploiting Relay Cache for Cellular Networks

In relay-enhanced cellular systems, throughput of User Equipment (UE) is constrained by the bottleneck of the two-hop link, backhaul link (or the first hop link), and access link (the second hop link). To maximize the throughput, resource allocation should be coordinated between these two hops. A common resource scheduling algorithm, Adaptive Distributed Proportional Fair, only ensures that the throughput of the first hop is greater than or equal to that of the second hop. But it cannot guarantee a good balance of the throughput and fairness between the two hops. In this paper, we propose a Two-Hop Balanced Distributed Scheduling (TBS) algorithm by exploiting relay cache for non-real-time data traffic. The evolved Node Basestation (eNB) adaptively adjusts the number of Resource Blocks (RBs) allocated to the backhaul link and direct links based on the cache information of relays. Each relay allocates RBs for relay UEs based on the size of the relay UE’s Transport Block. We also design a relay UE’s ACK feedback mechanism to update the data at relay cache. Simulation results show that the proposed TBS can effectively improve resource utilization and achieve a good trade-off between system throughput and fairness by balancing the throughput of backhaul and access link.

Research of multi-path routing based on network coding in space information networks

A multi-path routing algorithm based on network coding is proposed for combating long propagation delay and high bit error rate of space information networks. On the basis of traditional multi-path routing, the algorithm uses a random linear network coding strategy to code data packets. Code number is determined by the next hop link status and the number of current received packets sent by the upstream node together. The algorithm improves retransmission and cache mechanisms through using redundancy caused by network coding. Meanwhile, the algorithm also adopts the flow distribution strategy based on time delay to balance network load. Simulation results show that the proposed routing algorithm can effectively improve packet delivery rate, reduce packet delay, and enhance network performance.

Sensing Performance Evaluation over Multihop System with Composite Fading Channel

Cognitive radio has been demonstrated for improved spectrum utilization by secondary users in the presence of spectrum holes. In this paper, a Cognitive Radio (CR) network is implemented over the cooperative multihop wireless link. A multihop network is a collection of relay nodes within transmitter and receiver. A fixed infrastructure based multihop architecture is assumed for the performance analysis of energy detection algorithm for spectrum sensing in CR. System performance estimation against channel impairments dominated by fading and shadowing effects is one of the prerequisite for performance analysis of such networks. An effort has been made for exact performance analysis of multihop wireless network over composite fading channels. The investigation lead to the findings i.e., for a given value of fading or shadowing parameter, the preferable detection probability is always dependent upon the optimum number of hops. Depending upon SNR a three- or five- hop link may perform better. For severe fading conditions, the one-hop link performs best.

Outage Analysis of Spectrum Sharing Cognitive DF Relay Networks Using Outdated CSI

We investigate the effect of the outdated channel state information (CSI) on the secondary relay-aided network's performance. We carry out the analysis of the outage probability as well as the diversity order of the secondary network (SN) considering three key constraints: 1) maximum transmit power at the secondary transmitter, 2) peak interference power at the primary receiver, and 3) outdated CSI at the secondary-to-primary and secondary-to-secondary links. The performance results show that the relay cluster position, the imperfect CSI of the interference links and of the second hop are the key optimization factors. We show that the correlation coefficient of the second hop link is the key optimization parameter of the diversity order.