Dynamic bandwidth reservation in hierarchical wireless ATM networks using GPS-based prediction

The article presents a dynamic connection admission control (CAC) and bandwidth reservation (BR) scheme for IEEE 802.16e Broadband Wireless Access networks to simultaneously improve the utilization efficiency of network resources and guarantee QoS for admitted connections. The proposed CAC algorithm dynamically determines the admission criteria according to network loads and adopts an adaptive QoS strategy to improve the utilization efficiency of network resources. After new or handoff connections enter the networks based on current admission criteria, the proposed adaptive BR scheme adjusts the amount of reserved bandwidth for handoffs according to the arrival distributions of new and handoff connections in order to increase the admission opportunities of new connections and provide handoff QoS as well. We conduct simulations to compare the performance of our proposed CAC algorithm and BR scheme with that of other approaches. The results illustrate that our approach can effectively improve the network efficiency in terms of granting more connections by as large as about 22% in comparison with other schemes, and can also guarantee adaptive QoS for admitted new and handoff connections.

A dynamic bandwidth reservation (DBR) scheme for hybrid IEEE 802.16 wireless networks is investigated, in which 802.16 networks serve as the backhaul for client networks, such as WiFi hotspots and cellular networks. The DBR scheme implemented in the subscription stations (SSs) (co-locating with access pointers) consists of two components: connection admission controller (CAC), and bandwidth controller (BC). The CAC processes the received connection set-up requests from the client networks connected to the SSs. The BC manages the request and release of bandwidth from the base station (BS). It dynamically changes the reserved bandwidth between a small number of values. Hysteresis is incorporated in bandwidth release to reduce bandwidth request signalling load and connection blocking probability. An analytical model is proposed to evaluate the performances of reserved bandwidth, connection blocking probability and signalling load. The impacts of hysteresis mechanism and probability of reservation request blocking are taken into account. Simulation verifies the analytical model.

Distributed middleware technology is emerging as a flexible promising solution for network resource management and QoS (quality of service) control in a distributed environment. The concept of dynamic bandwidth reservation (DBR) algorithm additionally allocates the terminated bandwidth for an ongoing call is one of the promising methods to reduce the new call blocking and handoff call dropping probabilities. Dynamic resource management (DRM) framework concentrates on design and developing a framework for allocating shared resources to support multiple QoS and to provide probabilistic assurances of service in wireless networks. Existing methods and architecture do not guarantee on resource allocation and management in mobile, wireless and ad hoc networks. When a mobile node (MN) moves from its home network (HN) to foreign network (FN), the minimal required resources and services can be provided locally in the current network where it is connected presently. Dynamic resource management (DRM) framework provides an application level simulator for wireless network with new QoS management concept. DRM framework comprises of a set of programmable distributed objects and distributed middleware. DRM framework is constructed using distributed objects and distributed middleware. Distributed object carry applications across networks and allow them to connect to local server with FN in the same way as they had moved from the HN. The framework must dynamically accommodate multimedia calls with different bandwidth requirements in response to network traffic and it supports mobility management. The utility of DRM framework describes how the required resources are reserved based on the user priority option in an adaptive manner. The proposed DBR algorithm guarantees the required bandwidth during call setup and handoff without any flow rejection.

In this paper, a call admission control mechanism is proposed to provide a consistent QoS guarantee for multimedia traffic on a mobile computing environment. Each cell can reserve fractional bandwidth for handoff calls to its adjacent cells. It is important to determine the right amount of bandwidth reserved for handoff calls because the blocking probability of new calls may increase if the amount of reserved bandwidth is more than necessary. An adaptive bandwidth reservation based on a mobility graph and a 2-tier cell structure is proposed to determine the amount of bandwidth to be reserved in the cell and to control dynamically its amount according to network conditions. We also propose a call admission control based on this bandwidth reservation and next-cell prediction scheme using a mobility graph. In order to evaluate the performance of our call admission control mechanism, we measure metrics such as blocking probability of new calls, dropping probability of handoff calls, and bandwidth utilization. The simulation results show that the performance of our mechanism is superior to that of existing mechanisms such as NR-CAT2, FR-CAT2, and AR-CAT2.

Next generation wireless networks target to provide quality of service (QoS) for multimedia applications. In this paper, the system supports two QoS criteria, i.e., the system should keep the handoff dropping probability always less than a predefined QoS bound, while maintaining the relative priorities of different traffic classes in terms of blocking probability. To achieve this goal, a dynamic multiple-threshold bandwidth reservation scheme is proposed, which is capable of granting differential priorities to different traffic class and to new ad handoff traffic for each class by dynamically adjusting bandwidth reservation thresholds. Moreover, in times of network congestion, a preventive measure by use of throttling new connection acceptance is taken. Another contribution of this paper is to generalize the concept of relative priority, hence giving the network operator more flexibility to adjust admission control policy by incorporating some dynamic factors such as offered load. The elaborate simulation is conducted to verify the performance of the scheme.

Video-on-demand (VoD) servers are usually over-provisioned for peak demands, incurring a low average resource efficiency. However, bandwidth shortage may still occur for individual videos as they share and contend for server resources. In this position paper, we propose a predictive workload management system for VoD servers targeting bandwidth. The system draws belief about future demand as well as demand volatility based on demand history using time series forecasting techniques. The prediction enables dynamic and efficient server bandwidth reservation with QoS guarantees. More importantly, we use a hedging technique similar to investment portfolio management and distribute workloads to multiple servers exploiting demand anti-correlation. The proposed system consolidates the workloads, enhances resource utilization, while in the meantime effectively controlling risk of server overload. The proposed methods are evaluated based on real-world VoD traces.

In cellular networks, an important practical issue is how to limit the handoff dropping probability efficiently. One possible approach is to perform dynamic bandwidth reservation based on mobility predictions. With the rapid advances in mobile positioning technology, and the widespread availability of digital road maps previously designed for navigational devices, we propose a predictive bandwidth reservation scheme built upon these timely opportunities. In contrast to the common practice of utilizing only incoming handoff predictions at each cell to compute the reservations, our scheme is more efficient as it innovatively utilizes both incoming and outgoing handoff predictions; it can meet the same target handoff dropping probability by blocking fewer new calls. The individual base stations are responsible for the computations, which are shown to be simple enough to be performed in real-time. We evaluate the scheme via simulation, along with five other schemes for comparison. Simulation results show that those schemes that rely on positioning information are significantly more efficient than those that do not. Our scheme's additional use of the road topology information further improves upon this advantage, bringing the efficiency closer to the bound set by a benchmark scheme that assumes perfect knowledge about future handoffs

Multimedia applications are much more sensitive to the quality of service(QoS) than text-based ones due to their data continuity. In order to provide a fast moving mobile host(MH) supporting multimedia applications with a consistent QoS, an efficient call admission mechanism is in need. This paper proposes the 2-level call admission control(2LCAC) scheme based on a call admission scheme using the priority to guarantee the consistent QoS for mobile multimedia applications. The 2LCAC consists of the basic call admission and advanced call admission; the former determines call admission based on bandwidth available in each cell and the latter determines call admission by utilizing delay tolerance time(DTT), priority queue(PQueue), and upgrade queue(UpQueue) algorithms. In order to evaluate the performance of our scheme, we measure the metrics such as the blocking probability of new calls, dropping probability of handoff calls, and bandwidth utilization. The result shows that the performance of our scheme is superior to that of existing schemes such as complete sharing policy(CSP), guard channel policy(GCP) and adaptive guard channel policy(AGCP).

Low earth orbit (LEO) satellites are deployed to provide global coverage and complement the performance of terrestrial wireless networks. In this paper, we propose a novel bandwidth allocation strategy along with a connection admission control technique aiming at improving the utilization of network resource and providing the network with better QoS guarantees such as new connection blocking probability (CBP) and handoff connection dropping probability (CDP) in multimedia LEO satellite networks. Our connection admission control scheme that we call the probability based dynamic channel reservation strategy (PDR) dynamically reserve bandwidth for real-time services based on their handoff probability, and the reserved bandwidth for real-time handoff connection can also be used by new connections under a certain probability determined by the mobility characteristics and bandwidth usage of the system. Simulation results have shown that, compared with other bandwidth allocation schemes, our scheme not only lowers the CDP for Class I real-time service, but also maintains the CBP to certain degree, thus offers very low call dropping probability for real-time connections while, at the same time, keeping resource utilization high

4G wireless communication expects to integrate different radio access technologies together to meet wide expectation from users and to support mobility. Call Admission Control (CAC) plays important role in such heterogeneous environment to effectively utilize network resources and to meet user QoS. This paper proposes IP Multimedia Subsystem (IMS) based integrated architecture for UMTS-WiMAX-WLAN overlay networks and Traffic Aware Dynamic Speed Sensitive CAC (TADSS-CAC) for these integrated heterogeneous networks. IMS architecture was designed by 3rd Generation partnership project (3GPP) and its main goal is to provide seamless multimedia connectivity between 3GPP standard and non 3GPP standard networks. In this paper IMS entity is used for interworking 3GPP based UMTS and non 3GPP based WiMAX and WLAN. Existing Speed Sensitive CAC (SS-CAC) preferably admits high velocity users to high coverage area network and low velocity users to low coverage area network that avoids unnecessary handoff and signaling overhead caused by high velocity user admitted to low coverage network. SS-CAC not considers specific network feature and traffic type for admitting calls. The Proposed TADSS-CAC preferably admits high velocity users either to WiMAX or UMTS (high Coverage networks) based on service type and low velocity or static users to WLAN except voice service. TADSS-CAC preferably admits low bandwidth loss tolerant delay sensitive services (eg., voice) to UMTS and huge bandwidth QoS restricted services (eg., video streaming, video conferencing) to WiMAX. TADSS-CAC also provides dynamic bandwidth reservation for handoff calls based on traffic condition that decreases packet loss, delay and increases network throughput. The proposed TADSS-CAC is applied for loose, tight, hybrid coupled UMTS-WiMAX-WLAN networks and performances are compared with existing SS-CAC.

Next generation mobile cellular networks will have to support multimedia services. These applications, however, are very different in relation to Quality of Service (QoS) requirements, imposing restrictive requirements for this type of environment because of its limited bandwidth. This work proposes alternative Call Admission Control (CAC) schemes combined with end-to-end bandwidth reservation. This work aims to attend the different multimedia services according to their different QOS requirements, as well as reducing the rate of call losses during the procedures of handoff, prioritizing users already using the network. Simulation results show that it is possible to guarantee satisfactory levels of handoff losses, maintaining the continuity of the calls and increasing user satisfaction.

Dynamic packet reservation multiple access (DPRMA) is a medium access control protocol for wireless multimedia applications. It allows the integration of both constant bit rate and variable bit rate traffic through a single access control mechanism that permits users to specify their bandwidth requirements. Users are allowed to repeatedly update this information in order to reflect any changes in their data rates. A base station analyzes the mobiles' requests, determines which can be accommodated, and conveys the resulting bandwidth assignments to the users. The ability of a mobile to initially reserve a portion of the channel capacity and to then dynamically alter this reservation is a primary feature of the system. In DPRMA, an attempt is made to match the capacity assigned to the user with the user generation rate. Furthermore, this capacity can be allocated using fractional or multiple slot assignments. The scheme is shown to provide improved performance over a system with a modified version of the packet reservation multiple access (PRMA) scheme.

This article proposes an analytical model of multi-service hierarchical wireless networks with implemented resource reservation mechanisms for handover calls and call overflow between networks covering the same area. The model allows the dynamic resource reservation mechanism as well as multiservice Pure Chance Traffic of Type 2 streams to be taken into account in the process of determination of parameters of overflow traffic. The applied approximate method for a determination of the average value and variance of traffic that overflows from resources of the first choice to resources of the second choice can be practically employed in cellular network optimization.

9 - Wireless ATM: An Enabling Technology For Multimedia Personal Communication

Most RC simulators handle only tree networks, not arbitrary networks. An algorithm is presented for computing signal delays in general RC networks using the RC-tree computation as the primary operation. The algorithm partitions a given network into a spanning tree and links. It computes the signal delay of the spanning tree, and updates the signal delay as it incrementally adds the links back to reconstruct the original network. If m is the number of links, this algorithm requires m(m+1)/2 updates and m+1 tree delay evaluations. All the tree delay evaluations involve computing signal delays with the same resistive spanning tree, but with different values for the capacitors.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>