The next-generation wireless networks need to support a wide range of multimedia applications with limited radio resources like bandwidth. In this paper, we propose a novel integrated framework for bandwidth degradation and call admission control (CAC) for multiclass real-time multimedia traffic in such networks. To increase the total carried traffic in an overloaded (saturated) wireless system, some of the ongoing calls in our framework are allowed to operate under a degraded mode, thereby releasing wireless channels that can be used to accommodate new calls, however, at the cost of user satisfaction. Indeed, an increase in carried traffic (i.e., provider's revenue generation) and user's quality-of-service satisfaction are two conflicting goals in a bandwidth allocation scheme. The proposed framework adequately models this tradeoff by introducing the negative revenue (i.e., loss) from bandwidth degradation, and finding the optimal degradation and admission policies that maximize the net revenue. When there is a mixture of real-time and nonreal-time calls in the system, the former are given preemptive priority over the latter, which are buffered for future admission in case of preemption. A channel sharing scheme is proposed for nonreal-time traffic and analyzed using a Markov modulated Poisson process-based queueing model. Detailed simulation experiments are conducted to validate our proposed framework.

Intelligent mobile terminals (or users) of next generation wireless networks are expected to initiate voice over IP (VoIP) calls using session set-up protocols like H.323 or SIP (session initiation protocol). To guarantee the service quality of such applications, the call set-up protocol should be robust against network impairments. We analyze the performance of the H.323 call set-up procedure over wireless links using a simple call model under two modes of operations, namely, regular and fast connect. The proposed model assumes the presence of a radio link protocol (RLP) and recommends that the VoIP packets be transferred without any RLP retransmissions, while H.323 control packets be transferred with RLP retransmissions. Our analytical models and detailed experiments show that the VoIP call set-up performance can undergo significant degradation if RLP is not used at all, even for moderately high frame error rates (FERs) in wireless links. On the other hand, a robust radio link layer, such as RLP, can improve the call-set-up delay performance as compared to the existing wireless voice call-set-up delay.

Intelligent mobile terminals (or users) of next generation wireless networks are expected to initiate voice over IP (VoIP) calls using session set-up protocols like H.323 or SIP (session initiation protocol). To guarantee service quality of such applications, the call set-up protocol should be robust against network impairment generated in wireless networks. In this paper, we analyze the performance of the H.323 call setup procedure over the wireless link. We used two call modes of operation for this analysis namely regular and fast connect. The proposed model assumes that a transparent radio link protocol (RLP), but without RLP retransmission, be used for VoIP packets while non-transparent (regular) RLP be used for H.323 control packets. Our analytical models prove that the VoIP call set-up performance can degrade significantly even for moderately high air-link frame error rates (FER). Furthermore, the call setup performance can be improved significantly using the robust radio link layer such as RLP with the modifications proposed in our paper. The analytical results were validated by our experimental measurements.

The wireless access is expected to be one of the key access technologies for providing IP services to the user, end-to-end seamlessly. The wireless network, as the "last hop" of the wireline IP network has its own unique set of complex characteristics. To improve the behavior of the wireless link susceptible to frequent error bursts (due to fading, shadowing etc.), various low layer (physical/link layer) techniques have to be used to map the service associated network level QoS parameters such as delay, jitter, BER and throughput to meet end-to-end IP performance. The motivation of this paper is two-fold: (i) to present some of the unique characteristics of the radio link and show what kind of flexibility of resource management and mapping techniques required to guarantee QoS over the wireless, and (ii) propose a framework for a wireless QoS agent. The wireless QoS agent, in a nutshell, will be responsible for mapping multimedia IP QoS requirements to radio link specific requirements. The wireless QoS agent will interwork with the IP QoS Manager framework within IETF such as diff-serv in core networks.

We present four efficient heuristics (one basic scheme and its three variants) to predict the location of a mobile user in a cellular wireless network. These location management schemes assume a hierarchy of location areas, which changes dynamically with traffic patterns, and estimate the location probabilities of each user. Depending on the movement profiles for the last τ time units, the most probable location area (MPLA) and the future probable location area (FPLA) are computed for the user. The basic scheme and its first variant attempt to find the user in the MPLA first and then in the FPLAs before searching the whole system area. The second variant attempts to predict the location probabilities of the user in the future cells, which are in turn predicted from the user-profile while forming the FPLA. It then forms an MPLA consisting of cells traversed in the last τ time units as well as the future cells. The third variant is a hybrid of the first and second variants. A probabilistic analysis of total paging cost is also presented for the basic scheme and its first variant. Finally, the proposed heuristics are validated and compared through extensive simulation studies under various traffic patterns.

Article Free Access Share on TCP source activity and its impact on call admission control in CDMA voice/data network Authors: Sanjoy Sen. Jastinder Jawanda Sortel Wireless Networks, 2201 Lakeside Boulevard, Richardson, TX Sortel Wireless Networks, 2201 Lakeside Boulevard, Richardson, TXView Profile , Kalyan Basu Sortel Wireless Networks, 2201 Lakeside Boulevard, Richardson, TX Sortel Wireless Networks, 2201 Lakeside Boulevard, Richardson, TXView Profile , Naveen K. Kakani Center for Research in Wireless Computing (CReW), Department of Computer Science, University of North Texas, Denton, TX Center for Research in Wireless Computing (CReW), Department of Computer Science, University of North Texas, Denton, TXView Profile , Sajal K. Das Center for Research in Wireless Computing (CReW), Department of Computer Science, University of North Texas, Denton, TX Center for Research in Wireless Computing (CReW), Department of Computer Science, University of North Texas, Denton, TXView Profile Authors Info & Claims MobiCom '98: Proceedings of the 4th annual ACM/IEEE international conference on Mobile computing and networkingOctober 1998 Pages 276–283https://doi.org/10.1145/288235.288323Published:25 October 1998Publication History 4citation356DownloadsMetricsTotal Citations4Total Downloads356Last 12 Months6Last 6 weeks2 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

We propose a novel channel management algorithm, called distributed load balancing with selective borrowing (D-LBSB), for cellular mobile networks. As an underlying approach, we start with a fixed channel assignment scheme where each cell is initially allocated a set of local channels, each to be assigned on demand to a user in that cell. The novelty of our D-LBSB scheme lies in handling the hot cell problem because it proposes to migrate unused channels from suitable cold cells to the hot ones through a distributed channel borrowing algorithm. With the help of a Markov model, the probability of a cell being hot and the call blocking probability in a cell are derived. Detailed simulation experiments are carried out in order to evaluate our proposed methodology. Performance comparison reveals that the D-LBSB scheme performs better than a centralized version in an overloaded system, and significantly better than several other existing schemes in terms of call blocking probability, under moderate and heavy loads.

We propose an optimistic quality-of-service (QoS) provisioning scheme for multimedia traffic in wireless networks. The scheme uses the standard classification of network traffic into two priority classes based on their bandwidth requirement and delay tolerance. We classify the users as local or departing based on their current coordinates in the cell. A call admission algorithm, a call management algorithm and a prediction based resource reservation algorithm which reserves the specified bandwidth (by borrowing channels from neighboring cells, if required) in the predicted destination cell(s) of a departing user are presented. A novel approach called bandwidth compaction is proposed which enables more efficient spectrum utilization. Simulation experiments show improvements of about 24% in the call blocking probability and 12% in the connection dropping probability over other bandwidth reserving schemes. An overall improvement of 24% in bandwidth utilization over other schemes not employing any bandwidth management technique, is also observed.

We propose an efficient dynamic load balancing scheme in cellular networks for managing a teletraffic hot spot in which channel demand exceeds a certain threshold. A hot spot, depicted as a stack of hexagonal 'ring' of cells, is classified as complete if all cells within it are hot. The rings containing only cold cells outside the hot spot are called 'peripheral rings'. Our load balancing scheme migrates channels through a structured borrowing mechanism from the cold cells within the 'rings' or 'peripheral rings' to the hot cells in the hot spot. For the more general case of an incomplete hot spot, a cold cell is further classified as cold safe, cold semi-safe or cold unsafe, and a demand graph is constructed from the channel demand of each hot cell from its adjacent cells in the next outer ring. The channel borrowing algorithm works on the demand graph in a bottom up fashion, satisfying the demands of the cells in each subsequent inner ring. Markov chain models are developed for a hot cell and detailed simulation experiments are conducted to evaluate the performance of our load balancing scheme. Comparison with an existing load balancing strategy under moderate and heavy teletraffic conditions, shows a performance improvement of 12% in terms of call blockade by our load balancing scheme.

We propose a dynamic load balancing scheme for the channel assignment problem in a cellular mobile environment.As an underlying approach, we start with a fixed channel assignment scheme where each cell is initially allocated a set of C channels, each to be assigned on demand to a user in the cell.A cell is classified as 'hot', if the degree of coldness of a cell (defined as the ratio of the number of available channels to the total number of channels for that cell), is less than or equal to some threshold value, h.Otherwise the cell is 'cold'.Our load balancing scheme proposes to migrate unused channels from underloaded cells to an overloaded one.This is achieved through borrowing a fixed number of channels from cold cells to a hot one according to a channel borrowing algorithm.A channel assignment strategy is also proposed based on dividing the users in a cell into three broad types -'new', 'departing','others'-and forming different priority classes of channel demands from these three types of users.Assignment of the local and borrowed channels are performed according to the priority classes.Next, a Markov model for an individual cell is developed, where the state is determined by the number of occupied channels in the cell.The probability for a cell being hot and the call blocking probability in a hot cell are derived, and a method to estimate the value of h (threshold) is given.Detailed simulation experiments are carried out in order to evaluate our proposed methodology.The performance of our load balancing scheme is compared with the fixed channel assignment, simple borrowing, and two existing strategies with load balancing (e.g., directed retry and CBWL), and a significant improvement of the system behavior is noted in all cases.Pennission to make digital/hard copies of all or part of this material for personal or classroom usc is granted without fee provided that the copies are not made or distributed for profit or commercial advantage, the copyright notice, the title of the publication and its date appear, and notice is given that copyright is by permission of the ACM, Inc.To copy otherwise, to republish, to post on servers or to redistribute to lists