Dynamic Bandwidth Allocation Mechanism Research Articles

An Improved Polling Mechanism for Dynamic Bandwidth Allocation of XGPON Networks

Abstract: One of the most well-known technologies that offers a large range of services at user’s fingertips without requiring the least amount of infrastructure is passive optical networks. This can be due to a particular component known as the passive optical spiller. In order to facilitate time division access for individual ONUs on a single optical fiber, the appropriate dynamic bandwidth allocation mechanism must be present at the OLT with the advent of user support. For bandwidth assignment by DBA, it is essential to determine the precious upstream bandwidth demand, and can be aided by the more frequent polling mechanism. The more frequent polling mechanism lead to erroneous bandwidth report problem, become more serious when the mechanism is employed in larger coverage area network (specifically larger channel delay). This IBR problem lead increase in upstream delay at higher load condition, it’s because of improper assignment of bandwidth and waste of bandwidth. The IBR issue is resolved by the improved polling and scheduling method presented in this paper. Instead of transmitting the bandwidth allotment in each downstream frame, the OLT uses this scheduling technique to send it all at once to a TCONT (i) of ONU (i) for the duration of the SI period. To counteract the channel delay impact, a unique polling technique is also presented that use the hybrid methodology in which the OLTs sends polling mechanism once per the Service interval but According to the simulation study’s findings, the suggested system reduces mean upstream delay for type 2, 3, and 4 traffic classes by 62% when compared to the EBU scheme and by up to 20% when compared to the XGIANT design.

LSTM-Based DWBA Prediction for Tactile Applications in Optical Access Network

Historically, the optical access network (OAN) plays a crucial role of supporting emerging new services such as 4 k, 8 k multimedia streaming, telesurgery, augmented reality (AR), and virtual reality (VR) applications in the context of Tactile Internet (TI). In order to prevent losing connectivity to the current mobile network and Tactile Internet, the OAN must expand capacity and improve the quality of Services (QoS) mainly for the low latency of 1 ms. The optical network has adopted artificial intelligence (AI) technology, such as deep learning (DL), in order to classify and predict complex data. This trend mainly focuses on bandwidth prediction. The software-defined network (SDN) and cloud technologies provide all the essential capabilities for deploying deep learning to enhance the performance of next-generation ethernet passive optical networks (NG-EPONs). Therefore, in this paper, we propose a deep learning long-short-term-memory model-based predictive dynamic wavelength bandwidth allocation (DWBA) mechanism, termed LSTM-DWBA in NG-EPON. Future bandwidth for the end-user is predicted based on NG-EPON MPCP control messages exchanged between the OLT and ONUs and cycle times. This proposed LSTM-DWBA addresses the uplink control message overhead and QoS bottleneck of such networks. Finally, the extensive simulation results show the packet delay, jitter, packet drop, and utilization.

Protection Schemes in HPON Networks Based on the PWFBA Algorithm.

In this paper, possibilities for network traffic protection in future hybrid passive optical networks are presented, and reasons for realizing and utilizing advanced network traffic protection schemes for various network traffic classes in these networks are analyzed. Next, principles of the Prediction-based Fair Wavelength and Bandwidth Allocation (PFWBA) algorithm are introduced in detail, focusing on the Prediction-based Fair Excessive Bandwidth Reallocation (PFEBR) algorithm with the Early Dynamic Bandwidth Allocation (E-DBA) mechanism and subsequent Dynamic Wavelength Allocation (DWA) scheme. For analyzing various wavelength allocation possibilities in Hybrid Passive Optical Networks (HPON) networks, a simulation program with the enhancement of the PFWBA algorithm is realized. Finally, a comparison of different methods of the wavelength allocation in conjunction with specific network traffic classes is executed for future HPON networks with considered protection schemes. Subsequently, three methods are presented from the viewpoint of HPON network traffic protection possibilities, including a new approach for the wavelength allocation based on network traffic protection assumptions.

A Novel Dynamic Bandwidth Allocation Scheme for XGPON based Mobile Fronthaul for Small Cell CRAN

Time division multiplexing passive optical networks (TDM-PON) have emerged as a promising technology for mobile fronthaul for small cell CRAN. The performance of such TDM-based PON mobile fronthaul for small cell CRAN greatly depends on efficient dynamic bandwidth allocation (DBA) mechanisms. In this paper, a novel DBA mechanism based on the concept of dynamic service interval for ITU-based TDM-PON (XG-PON) for mobile fronthaul has been proposed. The proposed scheme is implemented using network simulator −3 (NS-3) simulation tool for evaluation of network performance parameters. The performance evaluation of the proposed DBA against the existing schemes such as optimized round robin (ORR) and Group-GIANT DBA shows a significant improvement in upstream mean delay, packet loss ratio and grant-request ratio. In addition to this, the proposed scheme shows that larger number of ONU(RRH) can be supported by the network for front haul uplink traffic transmitted via XG-PON in small cell CRAN.

Bandwidth Allocation-Based Distributed Event-Triggered LFC for Smart Grids Under Hybrid Attacks

In this study, a bandwidth allocation-based distributed event-triggering load frequency control (LFC) has been developed for smart grids to deal with hybrid cyber-attacks, for example, denial-of-service (DoS) attacks and false data injection (FDI) attacks. Firstly, to prevent hybrid cyber-attacks from causing open-loop unstable operation of the LFC systems, we propose a distributed event-triggering communication (ETC) strategy. To attain the maximum usage of bandwidth, a dynamic bandwidth allocation mechanism is integrated with the ETC approach on the basis of resource availability and error between the current state and equilibrium state. This bandwidth reservation and allocation approach aim at detecting attacks and assigning bandwidth to the different channels of distribution networks. Then, by virtue of the Lyapunov approach, the exponential stability criteria are established. Further, the exclusion of Zeno behavior of the designed systems is proved during the control process. Finally, comprehensive case studies show that the proposed method can improve the utilization rate of the network resource.

Security enhanced dynamic bandwidth allocation algorithm against degradation attacks in next generation passive optical networks

The dynamic bandwidth allocation (DBA) algorithm is highly impactful in improving the network performance of gigabit passive optical networks (GPON). However, reports delineating its vulnerability to certain attacks can be found in the literature, thus raising concerns. A degradation attack manipulates the transmission control protocol (TCP) congestion control algorithm, which may impact the received bandwidth of targeted network users. Here, the absence of electronics within the passive splitter renders attack identification in GPONs a significant challenge. Therefore, the current study aimed to propose a secured DBA mechanism known as security enhanced DBA capable of overcoming this particular threat. A detection phase served as a critical component for sensing and subsequently mitigating any abnormal behaviors observed among optical network units (ONUs). Upon identification of the attacker, penalties were imposed to deter the next attack attempt and reestablish the fairness to previously attacked ONUs. The simulation findings revealed throughput improvement of up to 63% due to the security feature offered by the mechanism. Besides, significant improvements for the upstream delay performance recorded at 52%, 60%, and 65% for traffic containers (TCONT) TCONT2, TCONT3, and TCONT4, respectively, were observed in comparison to the non-secure DBA mechanism. Hence, the integration of the security mechanisms in DBA renders it possible to avoid any exploitation of GPON vulnerability in hacking other users’ bandwidth.

A QoS-Aware Dynamic Bandwidth Allocation Algorithm for Passive Optical Networks with Non-Zero Laser Tuning Time

The deployment of new 5G services and future demands for 6G make it necessary to increase the performance of access networks. This challenge has prompted the development of new standardization proposals for Passive Optical access Networks (PONs) that offer greater bandwidth, greater reach and a higher rate of aggregation of users per fiber, being Time- and Wavelength-Division Multiplexing (TWDM) a promising technological solution for increasing the capacity by up to 40 Gbps by using several wavelengths. This solution introduces tunable transceivers into the Optical Network Units (ONUs) for switching from one wavelength to the other, thus addressing the ever-increasing bandwidth demands in residential broadband and mobile fronthaul networks based on Fiber to the Home (FTTH) technology. This adds complexity and sources of inefficiency, such as the laser tuning time (LTT) delay, which is often ignored when evaluating the performance of Dynamic Bandwidth Allocation (DBA) mechanisms. We present a novel DBA algorithm that dynamically handles the allocation of bandwidth and switches the ONUs’ lasers from one wavelength to the other while taking LTT into consideration. To optimize the packet delay, we introduce a scheduling mechanism that follows the Longest Processing Time first (LPT) scheduling discipline, which is implemented over the Interleaved Polling with Adaptive Cycle Time (IPACT) DBA. We also provide quality of service (QoS) differentiation by introducing the Max-Min Weighted Fair Share Queuing principle (WFQ) into the algorithm. The performance of our algorithm is evaluated through simulations against the original IPACT algorithm, which we have extended to support multi-wavelengths. With the introduction of LPT, we obtain an improved performance of up to 73% reduction in queue delay over IPACT while achieving QoS differentiation with WFQ.

Impact of security breach on the upstream delay performance of next generation gigabit passive optical networks

The next generation passive optical networks (NG-GPON) such as long reach GPON is the future-proof solution to answer the continuous demands for access user bandwidth and network expansion. However, security which is yet to be addressed in NG-GPON needs urgent attention as it will become more critical due to much longer distance, denser user population and more network elements. In addition, the longer propagation delay in NG-GPON can also lead to a more complex bandwidth allocation mechanism that is expected to operate in a dynamic manner. Among the highlights of recommendations for future implementation are improvements in the security aspect and the use of dynamic bandwidth allocation (DBA) algorithm that suit the characteristics of long reach GPON. Current PON is exposed to degradation attack, a security breach that can harm how bandwidth fairness mechanism among ONUs work. Thus, this project proposes a secured DBA mechanism for NG-PON that could overcome this particular threat. In specific, a detection phase will be included in the DBA mechanism to sense and subsequently mitigate abnormal behaviours among ONUs that are harmful to the goal of DBA i.e. to ensure QoS among ONUs and traffics. At the same time, careful attention is given on the delay parameter as it is a critical parameter that can affect DBA performance in long reach GPON. In this paper, preliminary analysis is shown that reveal how possibility of threats increase with increasing of distance and network elements.

Staged priority-based dynamic bandwidth allocation in software-defined hybrid passive optical network

A software-defined hybrid passive optical network (HPON) architecture is proposed, in which multiple PON systems using various physical layer (PHY) multiplexing technologies can coexist. The detailed upstream bandwidth allocation procedure is illustrated, and the dynamic bandwidth allocation mechanism in software-defined HPON is primarily investigated. By introducing the concept of virtual PON (VPON), an elaborate staged priority-based dynamic bandwidth allocation (SPB-DBA) mechanism for inter-VPON is proposed, which consists of a delicate two-stage admission scheme of bandwidth allocation to avoid frequent bandwidth reallocation, and an exquisite weighted bandwidth allocation algorithm to allocate bandwidth for VPONs with priority level and bandwidth demand priority differentiation. The simulation results demonstrate that the SPB-DBA mechanism provides distinctive bandwidth support for VPONs with differentiated priority levels and ensures the access fairness among VPONs. Furthermore, the performances in terms of bandwidth utilization, average satisfaction ratio, and packet average delay are significantly improved.

Performance Evaluation of XG-PON Based Mobile Front-Haul Transport in Cloud-RAN Architecture

Time division multiplexing passive optical network (TDM-PON) technologies are viewed as an attractive solution for flexible and cost-efficient mobile front-haul for cloud radio access network (C-RAN) architecture. However, it is a challenge for TDM-PONs to meet the strict latency requirement of mobile front-haul in C-RAN because they use a dynamic bandwidth allocation (DBA) mechanism to manage upstream traffic. The latency issue of TDM-PON based mobile front-haul has been extensively investigated in the literature with particular focus on IEEE TDM-PON (e.g., 10G-EPON). However, ITU TDM-PONs such as XG-PON and XGS-PON have not yet even been explored in the context of mobile front-haul. To cover this gap, we first evaluate the performance of two recently proposed XG-PON-standard-compliant DBAs, namely, group-assured GIANT (gGIANT) and round-robin DBA (RR-DBA), over simulated mobile front-haul traffic. We conclude based on our evaluation that neither RR-DBA nor gGIANT satisfies the delay required for mobile front-haul. Therefore, we propose an optimized DBA known as optimized round-robin (optimized-RR) that support front-hauling over XG-PONs. The performance evaluation of our optimized DBA against gGIANT and RR-DBA shows significant improvement in upstream delay and utilization as well as lower packet loss and jitter for front-haul uplink traffic transmitted via XG-PON in virtualized C-RAN architecture.

A Novel Resource Allocation and Power Control Mechanism for Hybrid Access Femtocells

LTE Small cells like Femto cells are being deployed in enterprises and residential buildings to improve data rates of indoor users who experience low Signal-to-Interference plus Noise Ratio (SINR) from Macro Base Stations (MBSs). Deployment of Femto cells inside a building can lead to signal leakage at the edges/corners of the buildings. This causes cross-tier interference and degrades the performance of users in High Interference Zone (HIZone) around the building area, who are connected to one of the MBSs in LTE Heterogeneous Networks (HetNets). Hybrid Access Femto cells (HAFs) can ensure QoS for paid Subscriber Group (SG) users by giving them preferential access to resource blocks over non-SG (NSG) users and also improve the throughput of LTE HetNet system by serving nearby NSG users. In this work, we address various challenges involved in deployment and operation of HAFs in indoor environments by proposing an Optimal Placement of Femto cell (OPF) model, a dynamic Bandwidth Allocation (BWA) mechanism for splitting resource blocks between SG and NSG users, a dynamic power control mechanism to mitigate co-tier and cross-tier interference in HetNets and an Enhanced Priority (EP) scheduling mechanism to give more priority to SG users over NSG users.During peak traffic load scenarios, HAFs may not be able to guarantee QoS of both indoor and HIZone users connected to them. As HAFs are primarily meant for indoor users, HAFs employ an Optimal Power Control (OPC) mechanism to tune their transmit powers so that HIZone users are offloaded to near-by MBSs. Since the OPC is a Mixed Integer Non-linear Programming (MINLP) problem, we put forth a Sub-Optimal Power Control (SOPC) mechanism. The SOPC mechanism boosts the throughput of MBSs by almost 62% over the traditional 3GPP proposed enhanced Inter-Cell Interference Co-ordination (eICIC) mechanism for 300 users in the HetNet system. Also, the proposed EP scheduling mechanism maintains Jain’s fairness index of 0.99 for both SG and NSG users while providing a 40% higher per user throughput than that obtained with the legacy proportional fair and Priority Set schedulers.

QoS-aware energy-saving mechanism for hybrid optical-wireless broadband access networks

Hybrid optical-wireless broadband access network (HOWBAN) takes full advantage of the high capacity and reliability of the passive optical network and the flexibility, ubiquity of the wireless network. Similar to other access networks, the issue of high energy consumption is a great challenge for HOWBAN. In HOWBAN, optical network units (ONUs) consume a great amount of energy. The sleep of ONUs can greatly improve the energy efficiency of HOWBAN. However, the quality of service (QoS) will be decreased while the packets are waiting in ONUs and optical line terminal. In this paper, we propose a QoS-aware energy-saving mechanism. A dynamic bandwidth allocation mechanism is designed to guarantee the QoS, where different priorities are considered. Meanwhile, we employ different sleep strategies by taking different priorities’ tolerant delays into account to prolong the sleep time of ONUs. Then, based on the evaluation of packet delay, the optimal sleep parameter is derived to maximum the energy efficiency. In addition, a load balancing and resource allocation mechanism is adopted in the wireless domain to reduce the delay and congestion caused by ONUs’ sleep. Results show that the proposed mechanism can effectively improve the energy efficiency and meet the QoS requirements of packets.

Grouping by Cycle Length (GCL) for long-range FiWi networks

The integration of wireless access networks with optical access networks in the so-called fiber-wireless (FiWi) networks has recently emerged as a promising strategy for providing flexible network services at relatively high transmission rates. FiWi network research to date has mainly focused on optical access networks with the normal reach (around 20km) of passive optical networks (PONs). We make two main contributions to the study of FiWi networking with a long-range PON with a propagation distance on the order of 100km in this paper. First, through extensive simulations, we investigate the packet delays when relatively low-rate traffic that has traversed a wireless network is mixed with conventional high-rate PON-only traffic. We consider a range of different FiWi network architectures with different dynamic bandwidth allocation (DBA) mechanisms. Second, we closely examine the grouping of the optical network units (ONUs) in the double-phase polling (DPP) DBA mechanism in long-range FiWi networks. We introduce a novel grouping by cycle length (GCL) strategy that achieves favorable packet delay performance.

High-performance adaptive hybrid wireless NoC architecture based on improved congestion measurement

In view of the high energy consumption and latency problem due to multi-hop wired links between distant cores of traditional large-scale Network-on-Chip, a virtual torus-based adaptive wireless NoC architecture has been proposed when analyzing the existing several wireless NoC architectures. By not only adopting the automatic detection and dynamic bandwidth allocation mechanism to hot wireless link based on the sensing parameter for improved congestion measurement, but also designing the Dynamic Allocation Control Circuit Module (DACCM) for transmitter, the intra-chip topology and link bandwidth could be adaptively adjusted as different traffic patterns. Experimental results show that the proposed architecture has more significant latency improvement and energy saving under different traffic patterns or real application such benchmark as FFT.

Energy-Saving Mechanism in WDM/TDM-PON Based on Upstream Network Traffic

One of the main challenges of Passive Optical Networks (PONs) is the resource (bandwidth and wavelength) management. Since it has been shown that access networks consume a significant part of the overall energy of the telecom networks, the resource management schemes should also consider energy minimization strategies. To sustain the increased bandwidth demand of emerging applications in the access section of the network, it is expected that next generation optical access networks will adopt the wavelength division/time division multiplexing (WDM/TDM) technique to increase PONs capacity. Compared with traditional PONs, the architecture of a WDM/TDM-PON requires more transceivers/receivers, hence they are expected to consume more energy. In this paper, we focus on the energy minimization in WDM/TDM-PONs and we propose an energy-efficient Dynamic Bandwidth and Wavelength Allocation mechanism whose objective is to turn off, whenever possible, the unnecessary upstream traffic receivers at the Optical Line Terminal (OLT). We evaluate our mechanism in different scenarios and show that the proper use of upstream channels leads to relevant energy savings. Our proposed energy-saving mechanism is able to save energy at the OLT while maintaining the introduced penalties in terms of packet delay and cycle time within an acceptable range. We might highlight the benefits of our proposal as a mechanism that maximizes the channel utilization. Detailed implementation of the proposed algorithm is presented, and simulation results are reported to quantify energy savings and effects on network performance on different network scenarios.

Proposed WFQ Based Dynamic Bandwidth Allocation for Mobile Wimax Application

In this project, we proposed a framework to support heterogenous traffic with different QoS demand in WiMAX. This framework dynamically changes the bandwidth allocation (BA) for ongoing and new arrival connections based on network condition andservice demand. The objective is to efficiently use the available bandwidth and provide QoS support in a fair manner. Dynamic allocation of spectrum prior to transmission can mitigate the starvation problem of Non Real time application. The WFQ based dynam ic bandwidth allocation framework uses architecture that has packet scheduler scheme (PS), call admission policy and a dynamic bandwidth allocation mechanism. By the simulation result we have showed that this architecture could provide QoS support by bei ng fair to all classes of services.

Implementation of a One-LLID-per-Queue DBA Algorithm in EPON

The advantages of Ethernet passive optical network (EPON) are setting it to be a natural ubiquitous solution for the access network. In the upstream direction of EPON, the directional property of the splitter requires that the traffic flow be mitigated to avoid collision. A dynamic bandwidth allocation (DBA) scheme is desirable in optimizing the bandwidth usage further. In this paper, a global priority DBA mechanism is discussed. The mechanism aims to reduce the overall delay while enhancing the throughput and fairness. This study was conducted using MATLAB where it was compared to two other algorithms in the literature. The results show that the delay is reduced up to 59% and the throughput and fairness index are improved up to 10% and 6%, respectively.

GPON-based transmission hierarchy for metro ring networks

Nowadays, almost all of metro network operators face the challenge that how to give a uniform support to multiple client networks, and meanwhile increase traffic's transmission efficiency. In an attempt to address this problem, here we first propose a gigabit passive optical network (GPON) based transmission hierarchy (GTH) for metro networks, by modifying the frame structures and application scenarios of traditional GPON technology. Then we study the GTH technology by analyzing the network operating principles and dynamic bandwidth allocation mechanisms. In order to evaluate GTH's performance, we build a simulation testbed for metro ring networks, and compare GTH with multi-service transport platform (MSTP) and technologies of packet transport network (PTN). Simulation results show that for transmission efficiency, GTH outperforms MSTP and is comparable to PTN. Furthermore, each time point of network expansion in GTH networks is further than it is in MSTP and PTN networks.

Impact of report message scheduling (RMS) in 1G/10G EPON and GPON

A wide array of dynamic bandwidth allocation (DBA) mechanisms have recently been proposed for improving bandwidth utilization and reducing idle times and packet delays in passive optical networks (PONs). The DBA evaluation studies commonly assumed that the report message for communicating the bandwidth demands of the distributed optical network units (ONUs) to the central optical line terminal (OLT) is scheduled for the end of an ONU's upstream transmission, after the ONU's payload data transmissions. In this paper, we conduct a detailed investigation of the impact of the report message scheduling (RMS), either at the beginning (i.e., before the pay load data) or the end of an ONU upstream transmission on PON performance. We analytically characterize the reduction in channel idle time with reporting at the beginning of an upstream transmission compared to reporting at the end. Our extensive simulation experiments consider both the Ethernet Passive Optical Networking (EPON) standard and the Gigabit PON (GPON) standard. We find that for DBAs with offline sizing and scheduling of ONU upstream transmission grants at the end of a polling cycle, which processes requests from all ONUs, reporting at the beginning gives substantial reductions of mean packet delay at high loads. For high-performing DBAs with online grant sizing and scheduling, which immediately processes individual ONU requests, or interleaving of ONUs groups, both reporting at the beginning or end give essentially the same average packet delays.

Dynamic bandwidth allocation mechanism in EPON with idle time eliminated

To improve the utilization of bandwidth in EPON (Ethernet Passive Optical Network), a novel dynamic bandwidth allocation algorithm is proposed. Logically, all ONUs are divided into two different zones logically. Further, the corresponding scheduling strategies for each zone are designed. As a result, traffic sending and granted can be achieved with the parallel manner by individual ONU in different zone. With our scheduling method, the sending operations of ONUs in different zones are consecutive in time domain, and the idle time can be eliminated effectively. As a result, the system efficiency can be improved. Results show that the performance of uplink throughput is promoted, and the mean delay of uplink traffic is decreased.