Performance analysis and evaluation of an enhanced power saving class type III in IEEE 802.16 with self-similar traffic

In order to improve the efficiency of the power saving mechanism and to save more resources in WiMAX, and also to consider the property of self-similar traffic shown widely in the networks with multimedia transmission, we present a new method to analyze the performance of an enhanced power saving class type III in IEEE 802.16 with self-similar traffics. According to the operating principle of the sleep mode in the enhanced power saving class type III, considering the self-similar nature of massive multimedia packets in wireless mobile networks, a discrete-time batch arrival multiple vacation queueing model with vacation-delay is built. The batch size is supposed to be Pareto distributed. The boundary state variable theory for the batch arrival vacation queueing model is presented, and then the queueing measures such as queueing length, waiting time and busy cycle in steady state are given. Moreover, we derive explicitly the performance measures in terms of the handover ratio, the energy saving ratio, the system utility and the average response time of packets. Finally, numerical results are given to demonstrate the influence of the system parameters on the system performance with different offered loads and different degrees of self-similar traffics. This paper provides a theoretical basis for the optimal design of the power saving mechanism in the IEEE 802.16, and has potential applications for solving other energy conservation related problems in wireless mobile networks.     

The power saving mechanism with binary exponential traffic indications in the IEEE 802.16e/m

In IEEE 802.16e (air interface standard for MWiMAX) and IEEE 802.16m (evolution of MWiMAX for IMT-Advanced), power saving is one of the important issues for the battery-powered mobile stations (MSs). According to IEEE 802.16e standard, when an MS switches from awake mode to sleep mode, the MS is required to send a sleep request (MOB-SLP-REQ) message and to receive a sleep response (MOB-SLP-RSP) message. In this paper we propose a new sleep mode scheme, called the power saving mechanism with binary exponential traffic indications. This sleep mode scheme omits MOB-SLP-REQ/RSP messages and has a traffic indication (TRF-IND) interval as a main system parameter, applying the truncated binary exponential increasing method for its length. The proposed scheme in this paper is quite well aligned with the design policy of sleep mode in discussion at IEEE 802.16m in the sense that it tries to minimize the overhead for the state transition between awake mode and sleep mode, and hence it can reduce the delay due to the state transition and enhance the power saving efficiency. We present a mathematical analysis for the proposed scheme and investigate its performance. As performance measures, we provide the sleep interval ratio, the average power consumption, and the mean delay. Using the analytical results, the system parameters such as the initial TRF-IND interval and the maximum binary exponent for TRF-IND intervals can be optimized while satisfying the QoS constraint on the mean delay. The numerical results show that the proposed scheme consumes less energy than the power saving class of type I in the IEEE 802.16e standard. This research was supported by the MKE (Ministry of Knowledge Economy), Korea, under the ITRC (Information Technology Research Center) support program supervised by the IITA (Institute for Information Technology Advancement) (IITA-2008-C1090-0801-0013).     

System modeling and performance analysis of the power saving class type II in BWA networks

For reducing the energy consumption of the Mobile Station in mobile Broadband Wireless Access networks, IEEE 802.16 offers three kinds of sleep mode operations called power saving classes type I, type II and type III. In order to investigate mathematically the inherent relationships between the performance measures and the system parameters, we propose in this paper a novel method for modeling the sleep mode with the power saving class type II in IEEE 802.16 and analyzing the performance of this sleep mode. Considering the attractive feature that some data frames can be transmitted during the listening state, we present a queueing model with two kinds of busy mechanisms to capture the working principle of the sleep mode operations with the power saving class type II. With the first and higher derivatives of the probability generating functions, we can give the averages and the standard deviations for the system performance using the diffusion approximation for the operating process of the system. We also propose methods for measuring the system performance in terms of the switching ratio, the energy saving ratio, and the average response time of data frames, as well as giving the expressions for these performance measures. Numerical results are provided with analysis and simulation to show the average performance measures, standard deviations and the cost function with different system loads. Moreover, we construct a cost function with the aim of determining the optimal time length of the sleep window to minimize the cost function.     

Resource allocation for end-to-end QoS provisioning in a hybrid wireless WCDMA and wireline IP-based DiffServ network

In the future UMTS network, the heterogeneous traffics of multimedia services demand various QoS provisioning. At the same time, the seamlessly conveying of information between mobile users and a hybrid network requires the networking from wireless to wireline domains. However, in both academia and industries, the end-to-end QoS provisioning in the integration of wireline and wireless networks remains a challenge. In this paper, a modeling of a hybrid wireless WCDMA and wireline IP-based DiffServ network is presented to investigate the resource allocation for end-to-end QoS provisioning for multimedia services. In the wireless domain, the mathematical modeling of the cross-layer model including the physical layer, the link layer and the network layer is built. The connection admission control scheme is implemented based on the cross-layer model to determine the amount of resource for different services. In the wireline domain, we define the mapping of QoS classes between UMTS and DiffServ networks according to different QoS requirements. We propose a bandwidth allocation scheme to provide satisfactory packet loss and delay guarantee in DiffServ networks. The final end-to-end admission control scheme combines the resource allocation and admission control in both wireless and wireline domains. The analytical and simulation results show that the proposed resource allocation and admission control schemes work cooperatively in the presented hybrid wireless and wireline networks to guarantee the end-to-end QoS requirements for multimedia services.     

Design and implementation of a hybrid MIPv6/PMIPv6-based mobility management architecture

As two of the most promising candidate solutions for realizing the next-generation all-IP mobile Internet, Mobile IPv6 (MIPv6) is a host-based protocol supporting global mobility, while Proxy Mobile IPv6 (PMIPv6) is a network-based protocol supporting localized mobility. In order to take full advantage of both and enhance the mobility performance, a hybrid MIPv6/PMIPv6-based mobility management architecture is proposed in this paper. First, the optimized coexistence architecture of MIPv6 and PMIPv6 is presented. Based on this architecture, the Hybrid scheme is proposed, in which localized mobility and global mobility are handled by PMIPv6 and MIPv6 respectively to improve the efficiency. Then we propose the Hybrid+ scheme based on the Hybrid scheme. The Hybrid+ scheme incorporates a protocol selection algorithm, which takes into account the mobility characteristics of mobile nodes (MN) and network conditions. This allows it to select the most suitable mobility supporting protocol between the basic MIPv6 and the Hybrid scheme. Performance analysis using a two-layer hierarchical network model reveals that the Hybrid scheme reduces the signaling costs by more than 20% compared to the basic MIPv6 and Hierarchical Mobile IPv6 (HMIPv6). In addition, we have implemented the proposed mobility management architecture in a test-bed. The experimental results show that our Hybrid scheme can improve the handover performance of UDP and TCP sessions over the other mobility management protocols. Moreover, when the protocol selection algorithm is adopted as in the Hybrid+ scheme, the performance can be further improved by more than 50% under various scenarios.     

Analysis of an MMPP/G/1/K queue with queue length dependent arrival rates,and its application to preventive congestion control in telecommunication networks

Recently telecommunication networks have been designed in order to transfer all types of information services such as voice, data and video. Next generation wireless networks has been developed to integrate the existing technologies and to support comprehensive services. As the traffics of diverse services have properties of timecorrelation and burstiness, unpredictable statistical fluctuation of traffic streams may cause congestion. To suggest a congestion control scheme which controls arrival rates according to the queue length, we consider an MMPP/G/1/K queue with queue length dependent arrival rates. The effect of system parameters on performance measures also is explained with the numerical examples.     

Location-area partition in a cellular radio network

With an increasing population of mobile subscribers, the signalling traffic to control the subscriber mobility expands rapidly. Subscriber mobility is controlled through location registration based on the so-called location area, the basic area unit for paging which consists of a number of cells. There is a tradeoff between the two kinds of signalling traffic: paging and location updating. As location areas include a larger number of cells, the traffic volume for paging increases while that for location updating decreases. Given not only the pattern of call arrivals but also that for subscriber mobility, our problem is to minimise the total signalling traffic by optimally partitioning the whole area into location areas. We show that this problem can be transformed to the so-called clique partitioning problem (CPP). Also we demonstrate the process of implementing the algorithm for solving the CPP for real-world problems defined on the cellular network in Seoul.     

Efficient content distribution in social-aware hybrid networks

Internet usage is increasing in two dimensions: the time users spend online and the amount of data they send and receive. The result is an increasing stress for the Internet infrastructure. Current developments like the trend towards video on demand and IPTV introduce even more bandwidth intensive services, which amplifies the demand for an efficient content delivery model. This article presents such a model which incorporates social awareness and is based on the combination of complementary networks, referred to as a hybrid network. Its applicability is further investigated and discussed by means of a YouTube video request analysis.     

Controlled mobility in stochastic and dynamic wireless networks

We consider the use of controlled mobility in wireless networks where messages arriving randomly in time and space are collected by mobile receivers (collectors). The collectors are responsible for receiving these messages via wireless transmission by dynamically adjusting their position in the network. Our goal is to utilize a combination of wireless transmission and controlled mobility to improve the throughput and delay performance in such networks. First, we consider a system with a single collector. We show that the necessary and sufficient stability condition for such a system is given by ρ<1 where ρ is the expected system load. We derive lower bounds for the expected message waiting time in the system and develop policies that are stable for all loads ρ<1 and have asymptotically optimal delay scaling. We show that the combination of mobility and wireless transmission results in a delay scaling of $\varTheta(\frac{1}{1-\rho})$ with the system load ρ, in contrast to the $\varTheta(\frac{1}{(1-\rho)^{2}})$ delay scaling in the corresponding system without wireless transmission, where the collector visits each message location. Next, we consider the system with multiple collectors. In the case where simultaneous transmissions to different collectors do not interfere with each other, we show that both the stability condition and the delay scaling extend from the single collector case. In the case where simultaneous transmissions to different collectors interfere with each other, we characterize the stability region of the system and show that a frame-based version of the well-known Max-Weight policy stabilizes the system asymptotically in the frame length.     

M/D^{[y]}/1 Periodically gated vacation model and its application to IEEE 802.16 network

In this paper we consider the analysis of an \(M/D^{[y]}/1\) vacation queue with periodically gated discipline. The motivation of introducing the new periodically gated discipline lies in modeling a kind of contention-based bandwidth reservation mechanism applied in wireless networks. The analysis approach applied here consists of two steps and it is based on appropriately chosen characteristic epochs of the system. We provide approximate expressions for the probability-generating function of the number of customers at arbitrary epoch as well as for the Laplace–Stieljes transform and for the mean of the steady-state waiting time. Several numerical examples are also provided. In the second part of the paper we discuss how to apply the periodically gated vacation model to the non real-time uplink traffic in IEEE 802.16-based wireless broadband networks.     

Adaptive channel and superframe allocation (ACSA) for 60 GHz wireless networks

Millimeter-wave (MMW) systems are high frequency wireless systems with a center frequency of around 60 GHz. In this article we propose an adaptive channel–superframe allocation (ACSA) scheme for such a system and evaluate its throughput and delay performance. The ACSA algorithm is designed to serve real-time (RT) and non-real-time (NRT) flows separately in different channels instead of serving them in different times. We also propose to change the sliced superframe of IEEE 802.15.3 to an adaptive unsliced superframe in order to decrease the TCP round-trip time. We compared IEEE 802.15.3 MAC with ACSA MAC, which shows that the throughput and delay could be improved in ACSA MAC. We observed significant improvement in the throughput of NRT flows via the better distribution of bandwidth in ACSA MAC. The channel access delay is also improved by providing an unsliced superframe. In brief, the simulation results also support the analysis of the proposed adaptive channel–superframe allocation algorithm, which could generally improve the quality of service (QoS) in MMW systems.     

基于IEEE802.16e的退避算法研究与改进

对IEEE802.16e的退避算法进行了研究,分析了该算法的不足,并进行了改进,提出了基站可随冲突MS数目动态调整起始退避窗大小的改进退避算法,给出了两种算法的仿真实验结果,证明了改进的算法可大大提高系统接入的性能,降低了接入冲突的概率.     

Toward a Reliable and Resilient Mobile Wireless Architecture

Abstract

Hybrid mobile wireless architectures that combine the advantages of ad hoc (mobile nodes) and cellular models provide “communications-on-the-move” services with enhanced flexibility and stability. In this article, we investigate the resiliency of such architectures by considering strategies for optimal deployment (number and location) of backup routers that would ensure reliable performance in such interdependent mobile systems.     

Random waypoint model in n-dimensional space

The random waypoint model (RWP) is one of the most widely used mobility models in performance analysis of mobile wireless networks. In this paper we extend the previous work by deriving an analytical formula for the stationary distribution of a node moving according to a RWP model in n-dimensional space.     

A hybrid model of the Akamai adaptive streaming control system

Video streaming is the application generating the largest fraction of the Internet traffic. Adaptive video streaming adds to classic video streaming the possibility of dynamically adapting the video bitrate to track the time-varying network available bandwidth, avoid playback interruptions and ensure the delivery of the best video quality. This work focuses on the adaptive video streaming control system employed by Akamai, a major Content Delivery Network operator whose video delivery system is used by several video streaming platforms, including Livestream. Differently from the typical client-side control, Akamai employs an interesting and unique hybrid client/server control architecture. In this paper we propose and experimentally validate a closed loop mathematical model of the control system in the form of a hybrid automaton. The model is analyzed to derive key properties which can be used to properly tune the controller parameters.     

Delay analysis of extended rtPS for VoIP service in IEEE 802.16e by matrix analytic method

Extended real time polling service (ErtPS) is added to IEEE 802.16e-2005 standards in order for VoIP service to use uplink resources efficiently by considering on/off characteristic of voice source. Recently average queueing delay of ErtPS algorithm for VoIP service was investigated, and it was shown that ErtPS allows to admit more users than UGS algorithm. But we need the probability distribution of queueing delay rather than average queueing delay in order to provide a necessary information for QoS. In this paper we obtain the probability distribution of queueing delay of ErtPS for VoIP service by using the matrix analytic method for the GI/M/1 type and the M/G/1 type matrices in cases of the service time being exponential and deterministic respectively. By applying the results on deterministic service time we find the maximum allowable number of VoIP users with the required constraint on queueing delay. This research was supported by the MIC (Ministry of Information and Communication), Korea, under the ITRC (Information Technology Research Center) support program supervised by the IITA (Institute of Information Technology Assessment).     

价格政策调整对上市公司影响的实证分析—以中国移动、中国联通香港上市公司为例

基于2000年左右电信管理部门的价格政策调整(下调),中国移动、中国联通香港公司相应的公告,以及关于手机单向收费的传言,实证检测发现,上市时间较短的中国联通比起较长时间上市的中国移动,受价格政策变动的冲击更为显著;对公司本身公告而言,中国移动反应显著而中国联通又反之;对手机单向收费信息期间的检测结果发现,二公司并没有大的异常收益。结论认为上市时间较短的公司股票(中国联通)受行业政策影响较为明显,而较长时间上市的公司股票(中国移动)受公司本身的经营环境、业绩变化的影响较大。     

Stability with file arrivals and departures in multichannel cellular wireless networks

This paper studies scheduling in multichannel wireless networks with flow-level dynamics. We consider a downlink network with a single base station, M channels (frequency bands), and multiple mobile users (flows). We also assume mobiles dynamically join the network to receive finite-size files and leave after downloading the complete files. A recent study van de Ven et al. (in Proc. IEEE Infocom., pp. 1701?C1709, 2009) has shown that the MaxWeight algorithm fails to be throughput-optimal under these flow-level dynamics. The main contribution of this paper is the development of joint channel-assignment and workload-based scheduling algorithms for multichannel downlink networks with dynamic flow arrivals/departures. We prove that these algorithms are throughput-optimal. Our simulations further demonstrate that a hybrid channel-assignment and workload-based scheduling algorithm significantly improves the network performance (in terms of both file-transfer delay and blocking probability) compared to the existing algorithms.     

Delay performance in random-access networks

We explore the achievable delay performance in wireless random-access networks. While relatively simple and inherently distributed in nature, suitably designed queue-based random-access schemes provide the striking capability to match the optimal throughput performance of centralized scheduling mechanisms in a wide range of scenarios. The specific type of activation rules for which throughput optimality has been established, may however yield excessive queues and delays. Motivated by that issue, we examine whether the poor delay performance is inherent to the basic operation of these schemes, or caused by the specific kind of activation rules. We derive delay lower bounds for queue-based activation rules, which offer fundamental insight in the cause of the excessive delays. For fixed activation rates, we obtain lower bounds indicating that delays can grow dramatically with the load in certain topologies as well.     

Initiating a state of the art system for real-time supply chain coordination

Intelligent Wireless Web (IWW) employs the capabilities of high speed wireless networks and exploits the parallel advancements in Internet-based technologies such as the Semantic Web, Web Services, Agent-based Technologies, and context awareness. Considering its great potentials to be applied in business systems, we have devised an innovative model, based on the IWW services, for a typical mobile real-time supply chain coordination system which has been developed and tested in a real operational environment. Our article investigates the proposed system in this way: at the start, the building blocks of the IWW are discussed in detail. Then, we fully explain the basic concepts of mobile real-time supply chain coordination and concentrate on the motivations to implement such a modern system. The vision of intelligent wireless web services, as discussed in this paper, centers on the need to provide mobile supply chain members highly specific data and services in real-time on an as-needed basis, with the flexibility of use for the user. In this regard, we investigate nine enabling technologies of the IWW for our system and discuss how, by exploiting the convergence and synergy between different technologies, it has become possible to deliver intelligent wireless web support to mobile real-time supply chain coordination. Afterwards, a practical framework is clearly established in four phases. This initiative system has been implemented in the laboratory and has passed the evaluation processes successfully. Further details will be announced in near future in another research article.