271 research outputs found
Optimization based bandwidth allocation in mobile cellular networks
No full textEfficient bandwidth allocation strategy with simultaneous fulfillment of QoS requirement of a user in a mobile cellular network is still a critical and an important practical issue. We explore the problem of minimizing the amount of time for which bandwidth has to be allocated in a cell while meeting the QoS constraint. With the knowledge about the the arrival and residence time distribution of a user in a cell, the above problem can be optimally solved using a dynamic programming based approach in polynomial time. To be able to use the solution, we provide a mechanism for constructing the arrival/residence time distribution based on the measurement of hand-off events in a cell. The above solution allows us to propose an optimal time based bandwidth reservation and call admission scheme. By being scalable and distributed, the proposed scheme justifies for practical implementation. Simulations results are also presented to show the effectiveness of the scheme to achieve the target QoS level and optimal bandwidth utilization.Technical report DCS-TR-45
Dynamic QoS Provisioning in Wireless Data Networks
No full textProviding quality of service(QoS) guarantees in mobile data networks is an inherently challenging task. Mobility of users imposes a spatial demand on resources resulting in overloaded regions that are entirely dependent on mobility pattern of users, that is often unpredictable. Prior and ongoing work in this area of QoS relies on call admission control (CAC), or careful resource allocation based on mobility prediction. The latter approach is not scalable, as it requires constant monitoring of the mobility of individual users and per-user state. Furthermore, many of the CAC schemes assume random or uniform mobility patterns, and in most cased are based on local decisions. The challenge is to design a scalable scheme that can provide QoS under distinct mobility patterns.
In contrast to the standard notion of QoS which is based on the handoff dropping probability, another important notion of QoS is based on disallowing handoff drops but minimizing the cell congestion probability that may occur in a given cell. In this paper, we explore this notion of QoS by proposing a dynamic CAC scheme that uses an dynamically estimated mobility pattern and distribution of users in different cells to reach an admission decision with the objective of minimizing cell congestion probability. This scheme does not maintain per user state, and can be implemented in a distributed fashion. From simulation results, we show that across different mobility patterns, the proposed scheme performs better than existing schemes in terms of achieved QoS while providing the minimum level of overall target utilization.Technical report DCS-TR-43
Measurement-based Modeling of Interference in Wi-Fi Networks: Techniques and Applications
No full textStony Brook University Libraries.
SBU Graduate School in Computer Science.
Lawrence Martin (Dean of Graduate School), Samir R. Das, Dissertation Advisor
Associate Professor, Department of Computer Science, Himanshu Gupta, Chairperson of Defense
Associate Professor, Department of Computer Science, Jennifer L. Wong, Third Member
Assistant Professor, Department of Computer Science, Samrat Ganguly, External Member
Director, Business Development, NEC Corporation of America
Cross-layer Design for Interference Mitigation and Mobility Support in Wireless Access Networks
No full textStony Brook University Libraries.
SBU Graduate School in Computer Science.
Lawrence Martin (Dean of Graduate School), Dr. Samir R. Das
Advisor
Associate Professor of Computer Science, Dr. Tzi-cker Chiueh
Professor of Computer Science, Dr. Himanshu Gupta
Assistant Professor of Computer Science, Dr. Samrat Ganguly
Research Staff Member
NEC Labs America at Princeton
"The fruits of independence": Satyajit Ray, Indian nationhood and the spectre of empire
No full textChallenging the longstanding consensus that Satyajit Ray's work is largely free of ideological concerns and notable only for its humanistic richness, this article shows with reference to representations of British colonialism and Indian nationhood that Ray's films and stories are marked deeply and consistently by a distinctively Bengali variety of liberalism. Drawn from an ongoing biographical project, it commences with an overview of the nationalist milieu in which Ray grew up and emphasizes the preoccupation with colonialism and nationalism that marked his earliest unfilmed scripts. It then shows with case studies of Kanchanjangha (1962), Charulata (1964), First Class Kamra (First-Class Compartment, 1981), Pratidwandi (The Adversary, 1970), Shatranj ke Khilari (The Chess Players, 1977), Agantuk (The Stranger, 1991) and Robertsoner Ruby (Robertson's Ruby, 1992) how Ray's mature work continued to combine a strongly anti-colonial viewpoint with a shifting perspective on Indian nationhood and an unequivocal commitment to cultural cosmopolitanism. Analysing how Ray articulated his ideological positions through the quintessentially liberal device of complexly staged debates that were apparently free, but in fact closed by the scenarist/director on ideologically specific notes, this article concludes that Ray's reputation as an all-forgiving, ‘everybody-has-his-reasons’ humanist is based on simplistic or even tendentious readings of his work
A Novel Radio Link Protocol for TCP Throughput Enhancement
No full textTo support TCP-based multimedia services on cellular networks, radio link protocols (RLP) are usually used to shield the channel related losses from TCP. In this paper, we categorize the RLP frames obtained by fragmenting a single TCP segment as crucial and non-crucial, and propose that different forward error correcting (FEC) schemes be applied to them. We find the fraction that constitute the crucial frames. We consider preemptive transmissions i.e., retransmissions of dropped or corrupt frames are given priority over new frames. Through qualitative analysis we demonstrate that the proposed RLP performs better than the traditional ones. We also show how the TCP throughput is improved because of the new RLP
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