A multiple-choice knapsack based algorithm for CDMA downlink rate differentiation under uplink coverage restrictions

This paper presents an analytical model for downlink rate allocation in Code Division Multiple Access (CDMA) mobile networks. By discretizing the coverage area into small segments, the transmit power requirements are characterized via a matrix representation that separates user and system characteristics. We obtain a closed-form analytical expression for the so-called Perron-Frobenius eigenvalue of that matrix, which provides a quick assessment of the feasibility of the power assignment for a given downlink rate allocation. Based on the Perron-Frobenius eigenvalue, we reduce the downlink rate allocation problem to a set of multiple-choice knapsack problems. The solution of these problems provides an approximation of the optimal downlink rate allocation and cell borders for which the system throughput, expressed in terms of downlink rates, is maximized. \u

Final report on the evaluation of RRM/CRRM algorithms

Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin

SCHEDULING IN PACKET SWITCHED CELLULAR WIRELESS SYSTEMS

In cellular wireless networks where users have independent fading channels, throughput for delay tolerant applications has been greatly increased on the downlink by using opportunistic schedulers at the base station. These schedulers exploit the multiuser diversity inherent in cellular systems. An interesting question is how opportunistic schedulers will provide Quality of Service(QoS) guarantees for a mix of data traffic and traffic from delay-sensitive multimedia applications. In the first part of this dissertation, we completely characterize the scheduled rate, delay and packet service times experienced by mobile users in a packet switched cellular wireless system in terms of a configurable base station scheduler metric. The metric used has a general form, combining an estimate of a mobile user's channel quality with the scheduling delay experienced by the user. In addition to quantifying the scheduler performance, our analysis highlights the inherent trade-off between system throughput and the delay experienced by mobile users with opportunistic scheduling. We also use this analysis to study the effect of prioritized voice users on data users in a cellular wireless system with delay constrained opportunistic scheduling. Our statistical analysis of the forward link is validated by extensive simulations of a system architecture based on the CDMA 1xEV-DO system. The increase in data traffic from mobiles to the base station has led to a growing interest in a scheduled reverse link in the 1xEV-DO system. We address the reverse link scheduling problem in a multi-cell scenario with interference constraints both within and outside the cell. This approach leads to a co-operative scheduling algorithm where each base station in a cellular network maximizes the sum of mobile data transmission rates subject to linear constraints on (1) the maximum received power for individual mobiles(2) the total interference caused by scheduled mobiles to (a) traffic and control channels of other mobiles within the cell and (b) mobiles in neighboring cells. Simulations of the reverse link structure based on the 1xEV-D0 system highlight the distinct advantages of this algorithm in ensuring predictable inter-cell interference and higher aggregate cell throughputs

A combinatorial approximation algorithm for CDMA downlink rate allocation

This paper presents a combinatorial algorithm for downlink rate allocation in Code Division Multiple Access (CDMA) mobile networks. By discretizing the coverage area into small segments, the transmit power requirements are characterized via a matrix representation that separates user and system characteristics. We obtain a closed-form analytical expression for the so-called Perron-Frobenius eigenvalue of that matrix, which provides a quick assessment of the feasibility of the power assignment for a given downlink rate allocation. Based on the Perron-Frobenius eigenvalue, we reduce the downlink rate allocation problem to a set of multiple-choice knapsack problems. The solution of these problems provides an approximation of the optimal downlink rate allocation and cell borders for which the system throughput, expressed in terms of utility functions of the users, is maximized

Efficient scheduling algorithms for quality-of-service guarantees in the Internet

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 167-172).The unifying theme of this thesis is the design of packet schedulers to provide quality-of- service (QoS) guarantees for various networking problem settings. There is a dual emphasis on both theoretical justification and simulation evaluation. We have worked on several widely different problem settings - optical networks, input-queued crossbar switches, and CDMA wireless networks - and we found that the same set of scheduling techniques can be applied successfully in all these cases to provide per-flow bandwidth, delay and max-min fairness guarantees. We formulated the abstract scheduling problems as a sum of two aspects. First, the particular problem setting imposes constraints which dictate what kinds of transmission patterns are allowed by the physical hardware resources, i.e., what are the feasible solutions. Second, the users require some form of QoS guarantees, which translate into optimality criteria judging the feasible solutions. The abstract problem is how to design an algorithm that finds an optimal (or near-optimal) solution among the feasible ones. Our schedulers are based on a credit scheme. Specifically, flows receive credits at their guaranteed rate, and the arrival stream is compared to the credit stream acting as a reference. From this comparison, we derive various parameters such as the amount of unspent credits of a flow and the waiting time of a packet since its corresponding credit arrived. We then design algorithms which prioritize flows based on these parameters. We demonstrate, both by rigorous theoretical proofs and by simulations, that these parameters can be bounded. By bounding these parameters, our schedulers provide various per-flow QoS guarantees on average rate, packet delay, queue length and fairness.by Anthony Chi-Kong Kam.Ph.D

Traffic integration in personal, local and geograhical wireless networks

Currently, users identify wireless networks with the first and second generation of cellular-telephony networks. Although voice and short messaging have driven the success of these networks so far, data and more sophisticated applications are emerging as the future driving forces for the extensive deployment of new wireless technologies. In this chapter we will consider future wireless technologies that will provide support to different types of traffic including legacy voice applications, Internet data traffic, and sophisticated multimedia applications. In the near future, wireless technologies will span from broadband wide-area technologies (such as satellite-based network and cellular networks) to local and personal area networks. Hereafter, for each class of networks, we will present the emerging wireless technologies for supporting service integration. Our overview will start by analyzing the Bluetooth technology that is the de-facto standard for Wireless Personal Area Networks (WPANs), i.e. networks that connect devices placed inside a circle with radius of 10 meters. Two main standards exist for Wireless Local Area Networks (WLANs): IEEE 802. and HiperLAN. In this chapter we focus on the IEEE 802.11 technology, as it is the technology currently available on the market. In this chapter, after a brief description of the IEEE 802.11 architecture, we will focus on the mechanisms that have been specifically designed to support delay sensitive traffics

EVEREST IST - 2002 - 00185 : D23 : final report

Deliverable públic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version