A capable location prediction and resource reservation scheme in wireless networks for multimedia

In this paper, NPS (neural network prediction scheme) is proposed to provide high accuracy location prediction of mobile host (MH) in target cell. Multimedia communications is urgently expected in wireless networks. One of the most important and complicated issues is quality of service guarantees in third-generation (3G) wireless networks. In other words, the problem to maintain the continuity of multimedia playing during the handoff is hard to solve. In order to avoid too early or over reservation resulting in a waste of resources, in this study, we present a method called TTRR (three times resource reservation scheme), to let reserved resource become really active upon MH entering into tire-2 (C.H. Choi, et al., Nov. 2000) area of cell. NSP and TTRR can efficiently improve the accuracy of MHs trajectory prediction, increase the success probability of resource reservation, and enhance bandwidth utilization.

Network protocols in cellular wireless data networks must update routes as a mobile host moves between cells. These routing updates combined with some associated state changes are called handoffs. Most current handoff schemes in wireless networks result in data loss or large variations in packet delivery times. Unfortunately, many applications, such as real-time multimedia applications and reliable transport protocols, adapt to long term estimates of end-to-end delay and loss. Violations and rapid fluctuations of these estimates caused by handoff processing often result in degraded performance. For example, loss during handoff adversely affects TCP performance [4], and high packet loss and variable delays result in poor real-time multimedia performance. In this paper, we describe a multicast-based protocol that eliminates data loss and incurs negligible delays during a handoff. The basic technique of the algorithm is to anticipate a handoff using wireless network information in the form of received signal strengths and to multicast data destined for the mobile host to nearby base stations in advance. This routing, combined with intelligent buffering techniques at the base stations, enables very rapid routing updates and eliminates data loss without the use of explicit data forwarding. We have implemented this protocol using IP Multicast and Mobile IP-like routing. In our implementation, handoffs typically take between 8 and 15 ms to complete and result in no data loss.

This paper addresses the Quality of Service (QoS) degradation problem of wireless relay node failures in multihop Worldwide interoperable Microwave Access (WiMAX) and Long Term Evolution (LTE) networks. In general, node protection in a communication network increases the reliability of the traffic flow from source to destination. For wireless networks, implementing the traditional 1+1 protection scheme increases the capital cost, as resources cannot be fully utilized. On the other hand, the design and implementation of the 1:N protection scheme in wireless networks for greater value of N (> 2) is very difficult, due to wireless network coverage and the physical layer design. To overcome the above drawbacks, a technique based on network coding is proposed for node protection in multihop wireless networks. In multihop wireless networks, few research efforts are concentrated on node protection schemes using network coding. Moreover, to best of our knowledge, no reports have been published on measuring the QoS performance for node protection in 4G wireless networks using network coding. In this paper, we first describe the node protection scheme using XOR network coding for multihop 4G wireless networks. Then, we measure the QoS performance, such as packet delivery ratio (PDR), latency and jitter, for different scenarios. The scenarios include a failure of a single relay node and failures of two relay nodes with and without our protection scheme and user's mobility. The simulation results show that the QoS performance with protection against a single relay node failure and failures of two relay nodes are very close to that of no failure scenario, while the network reliability increases due to the protection mechanism. Also, we report a decoding problem in multihop wireless networks using XOR network coding.

Resource reservation with mobile hosts using fuzzy matrices

A dynamic call admission control (CAC) and its associated resource reservation (RR) schemes are proposed in this research based on the guard channel (GC) concept for a wireless cellular system supporting multiple QoS classes. A comprehensive service model is developed, which includes not only mobile terminals' bandwidth requirements but also their different levels of priorities, rate adaptivity and mobility. The proposed CAC policy selects the resource access thresold according to the estimated number of incoming call requests of different QoS classes. The amount of resources to be reserved is dynamically adjusted by considering neighboring-cell higher-priority calls which are likely to handoff. The handoff interaction between adjacent cells is estimated by using radio propagation in terms of the signal-to-noise ratio (SNR) and the distance of each active call in neighboring cells. Experiments are conducted by using the OPNET simulator to study the performance of the proposed scheme under various traffic conditions. It is shown that better QoS guarantees can be provided by the proposed CAC and RR schemes.

Scarcity of the spectrum resource and mobility of users make quality of service (QoS) provision a critical issue in wireless networks. This paper presents a fuzzy call admission control scheme to meet the requirement of the QoS. A performance measure is formed as a weighted linear function of new call and handoff call blocking probabilities. Simulation compares the proposed fuzzy scheme with an adaptive channel reservation scheme. Simulation results show that fuzzy scheme has a better robust performance in terms of average blocking criterion.

A Framework to Facilitate Network Operators to Provide Better Quality of Service in Mobile Networks

본 논문에서는 모바일 네트워크에서 자원 예약으로 인해서 낭비되는 무선 자원을 개선하기 위한 윈도우 기반 자원 예약 기법을 제안한다. 특히 이 기법은 차별화 된 핸드오프 예측 모델을 기반으로 모바일 호스트들이 셀에서 이동하는 횟수를 이용하여 적절한 자원 예약 시점을 결정한다. 기존의 자원 예약 기법에서는 모바일 호스트가 셀에 도착하거나 생성되면 바로 자원 예약을 요청한다. 그러나 본 논문에서 제안하는 기법은 차별화 된 핸드오프 예측 모델에서 제공하는 추정된 내부 영역 이동 횟수를 기반으로 일정 시간이 경과한 후에 자원을 예약하므로 자원 이용율을 향상시킬 수 있다. 그리고 이웃 셀들에 대한 자원 예약 요청 비율에 따라 차별화 된 자원 예약을 실시하여 전체적인 자원 예약 성공율 및 대역폭 이용율을 향상시킨다. In this paper, we propose a window based resource reservation scheme to minimize an waste bandwidth due to resource reservation in mobile networks. Specially, this scheme decides a proper timing to reserve resource by using the number of movement, which is provided by the differentiated handoff estimation model, among inner regions. In the previous resource reservation scheme[6], it requests a resource reservation to neighboring cells as soon as a mobile host enters or creates into a cell. But, after a proper time based on the number of movements in the differentiated handoff estimation model passes, the proposed scheme requests a resource reservation to neighboring cells. Because of this reason, it can improve resource utilization on mobile networks. And, this scheme differentiates resource reservation according to a request ratio for resource reservation to each neighboring cell. Also, this scheme improves resource reservation acceptance rate and bandwidth utilization.

This paper proposes a location-based MAC (LMAC) scheme for wireless networks with randomly placed nodes. This scheme regulates channel access by sharing local location information among transmitters. A lattice approximation approach is used to derive upper and lower bound for the success probability for a typical transmission attempt. Numerical results show that with the node density and link distance fixed, the optimal LMAC provides a much higher density of successful transmissions than CSMA and ALOHA.

Dynamic slot assignment protocol for QoS support on TDMA-based mobile networks

We introduce a variety of mechanisms to enable scalable, adaptive, and reliable quality of service (QoS) guarantees across heterogeneous networking environments. The resultant scalable resource reservation scheme (SRRS) is the first resource management scheme that provides efficient fault protection based on the virtual reservation mechanism and a penalty-based adaptable reservation mechanism, so that QoS can continue to be guaranteed in the presence of faults without wasting expensive network resources unnecessarily. Based on the proposed geographical reservation mechanism and virtual IP addressing, SRRS can enable QoS guarantees in ad hoc mobile wireless networks. Also, resource reservation and allocation in SRRS are adaptive to the networking environments so that wireless QoS-guarantee issues can be resolved in the presence of mobility, making SRRS suitable for wireless mobile networks. We evaluate the performance of SRRS based on simulation and analysis, and show that SRRS can achieve considerably lower blocking rates as compared to previous reservation protocols.

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.

Wireless communication that provides voice only is not sufficient to support the necessity of user. In the future, the major advantage of third generation wireless communication (3G) are providing packet data communication, mobile Internet, and mobile multimedia data communication. This kind of data type requires more bandwidth to transmit data. Sometimes, the communication would be encountered the transmitting block because the new cell has no enough resource allocating to mobile station (MS or MH) in handoff. How to reduce the losing probability of data packets in wireless communication networks is important things which can raise the quality of service (QoS) and degrade the time and resource consume. In this paper, a resource reservation method is proposed to improve QoS and resource switching management to reduce data packet loss for multimedia communication at handoff operation.

The scheme proposed in this paper balances the partly conflicting objectives of meeting the diverse quality of service (QoS) needs of mobile hosts (MHs) and achieving high uplink throughput in a Direct Sequence Code Division Multiple Access (DS-CDMA) based cellular network. The QoS needs of the MHs are modeled using the notion of a service curve, which is a function characterizing the minimum number of bits a MH must transmit in any given time interval in order to meet its QoS requirement. Each MH is also assumed to have a specified bound on the acceptable bit error rate.The technique proposed in this paper maximizes the uplink throughput subject to the service curve constraints by jointly adapting the transmitted power and the number of spreading codes used by each MH in relaying its data bits. During this joint adaptation, the technique also imposes specified bounds on the transmitted power and the number of spreading codes that a MH can handle. The proposed technique is evaluated using a discrete-event simulation. The evaluation shows that the proposed scheme can effectively balance the two above-mentioned objectives.

Multimedia is imminently expected in the wireless networks. One of the most important and complex issues is quality of service (QoS) guarantees in the 3rd generation wireless networks. The purpose of this paper is to propose a probabilistic resource estimation and semi-reservation scheme in considering the probability of real usage made by the mobile host (MH). This scheme can efficiently improve the connection-blocking probability (CBP), connection-dropping probability (CDP), and bandwidth utilization.