Download or read book Scheduling Algorithm Design in Multiuser Wireless Networks written by Yi Chen and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we discuss throughput-optimal scheduling design in multiuser wireless networks. Throughput-optimal scheduling algorithm design in wireless systems with flow-level dynamics is a challenging open problem, especially considering that the majority of the Internet traffic are short-lived TCP controlled flows. In future wireless networks supporting machine-to-machine and human-to-human applications, both short-lived dynamic flows and long-lived persistent flows coexist. How to design the throughput-optimal scheduling algorithm to support dynamic and persistent flows simultaneously is a difficult and important unsolved problem. Our work starts from how to schedule short-lived dynamic flows in wireless systems to achieve throughput-optimality with queue stability. Classic throughput-optimal scheduling algorithms such as the Queue-length based Maxweight scheduling algorithm (QMW) cannot stabilize systems with dynamic flows in practical communication networks. We propose the Head-of-Line (HOL) access delay based scheduling algorithm (HAD) for flow-level dynamic systems, and show that HAD is able to obtain throughput-optimality which is validated by simulation.As the Transmission Control Protocol (TCP) is the dominant flow and congestion control protocol for the Internet nowadays, we turn our attention to the compatibility between throughput-optimal schedulers and TCP. Most of the existing throughput-optimal scheduling algorithms have encountered unfairness problem in supporting TCP-controlled flows, which leads to undesirable network performance. Motivated by this, we first reveal the reason of the unfairness problem, then study the compatibility between HAD and TCP with different channel assumptions, and finally analyze the mean throughput performance of HAD. The result shows that HAD is compatible with TCP.Since the assumption of an infinite buffer size in the existing theoretical analysis of throughput-optimality is not practical, we analyze the queueing behaviour of the proposed throughput-optimal scheduling algorithm to provide useful guidelines for real system design by using the Markov chain analytic model. We propose the analytic model for the queuing and delay performance for the HAD scheduler, and then further develop an approximation approach to reduce the complexity of the model. Finally, we propose a throughput-optimal scheduling algorithm for hybrid wireless systems with the coexistence of persistent and dynamic flows. Then, to generalize the throughput-optimal scheduling, the control function in the scheduling rule is extended from a specific one to a class of functions, so that the scheduling design can be more flexible to make a tradeoff between delay, fairness, etc. We show that the hybrid wireless networks with coexisting persistent flows and dynamic flows can be stabilized by our proposed scheduling algorithm which can obtain throughput-optimality.In summary, we solve the challenging problem of designing throughput-optimal scheduling algorithm in wireless systems with flow-level dynamics. Then we show that our algorithm can support TCP regulated flows much better than the existing throughput-optimal schedulers. We further analyze the queueing behaviour of the proposed algorithm without the assumption of infinite buffer size that is often used in the throughput-optimality analysis in the literature, and the result provides a guideline for the implementation of our algorithm. At last, we generalize the proposed scheduling algorithm to support different types of flows simultaneously in practical wireless networks.

Download or read book Scheduling in Multi user Mimo Wireless Systems written by George Maina Mureithi and published by . This book was released on 2011 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is widely believed that the implementation of multi-user multiple-input multiple- output (MU-MIMO) technology at the radio access portion of current and future wireless networks would positively impact on the performance of such networks. This however demands the design of efficient multi-user scheduling algorithms at the data link layer. One algorithm that is known to be throughput optimal is the opportunistic scheduler. This work takes a cross-layer approach in designing a scheduler that takes into account both the channel and queue states of users. We propose a scheduling algorithm referred to as the Maximum Throughput Scheduler (MTS). The MTS explicitly expresses network throughput as the utility function. Through simulations, we show that the MTS outperforms other schedulers in terms of network throughput.

Download or read book Scheduling and Resource Allocation in Multi user Wireless Systems written by Xuan Wang and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we discuss various aspects of scheduling and resource allocation in multi-user wireless systems. This work starts from how to utilize advanced physical-layer technology to improve the system performance in a multi-user environment. We show that by using superposition coding (SPC) and successive interference cancellation, the system performance can be greatly improved with utility-based scheduling. Several observations are made as the design guideline for such system. Scheduling algorithms are designed for a system with hierarchical modulation which is a practical implementation of SPC. However, when the utility-based scheduling is designed, it is based on the assumption that the system is saturated, {\em i.e.}, users in the system always have data to transmit. It is pointed out in the literature that in a system with stochastic traffic, even if the arrival rate lies inside the capacity region, the system in terms of queue might not be stable with the utility-based scheduling. Motivated by this, we have studied the stability region of a general utility-based scheduling in a multi-user system with stochastic traffic. We show that the stability region is generally less than the capacity region, depends on how to interpret an intermediate control variable, and the resultant stability region may be even non-convex and exhibits undesirable properties which should be avoided. As the utility-based scheduling cannot achieve throughput-optimal, we turn our attentions to the throughput-optimal scheduling algorithms, whose stability region is identical to the capacity region. The limiting properties of an overloaded wireless system with throughput-optimal scheduling algorithms are studied. The results show that the queue length is unstable however the scheduling function of the queue length is stable, and the average throughput of the system converges. Finally we study how to schedule users in a multi-user wireless system with information-theoretic security support, which is focused on the secrecy outage probability. The problem is essentially about how to schedule users, and allocate resources to stabilize the system and minimize the secrecy outage probability. We show that there is a tradeoff between the arrival rate of the traffic and the secrecy outage probability. The relative channel condition of the eavesdropper also plays an important role to the secrecy outage probability. In summary, we showed utility-based scheduling using SPC can improve the system performance greatly, but the utility-based scheduling has limitations: the stability region might not have desired properties. On the contrary throughput-optimal scheduling has its own drawbacks: the traffic cannot be handled properly if the system is overloaded. The further study on the secrecy outage probability gives guideline on how to design a scheduler in a system with information-theoretic security support.

Download or read book Wireless Network Design written by Jeff Kennington and published by Springer Science & Business Media. This book was released on 2010-11-10 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book surveys state-of-the-art optimization modeling for design, analysis, and management of wireless networks, such as cellular and wireless local area networks (LANs), and the services they deliver. The past two decades have seen a tremendous growth in the deployment and use of wireless networks. The current-generation wireless systems can provide mobile users with high-speed data services at rates substantially higher than those of the previous generation. As a result, the demand for mobile information services with high reliability, fast response times, and ubiquitous connectivity continues to increase rapidly. The optimization of system performance has become critically important both in terms of practical utility and commercial viability, and presents a rich area for research. In the editors' previous work on traditional wired networks, we have observed that designing low cost, survivable telecommunication networks involves extremely complicated processes. Commercial products available to help with this task typically have been based on simulation and/or proprietary heuristics. As demonstrated in this book, however, mathematical programming deserves a prominent place in the designer's toolkit. Convenient modeling languages and powerful optimization solvers have greatly facilitated the implementation of mathematical programming theory into the practice of commercial network design. These points are equally relevant and applicable in today’s world of wireless network technology and design. But there are new issues as well: many wireless network design decisions, such as routing and facility/element location, must be dealt with in innovative ways that are unique and distinct from wired (fiber optic) networks. The book specifically treats the recent research and the use of modeling languages and network optimization techniques that are playing particularly important and distinctive roles in the wireless domain.

Download or read book Advanced Opportunistic Multiuser Scheduling for Wireless Communications written by PhuongBang Nguyen and published by . This book was released on 2015 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation addresses key aspects of opportunistic multiuser scheduling, one of the main components of next generation wireless networks responsible for achieving maximum spectrum efficiency and superior user experience. The main topics include the exploitation of multiuser diversity and spatial frequency reuse while maintaining user fairness, the design and analysis of fair scheduling policies that can provide optimal performance, the utilization of historical channel data in scheduling, and the Quality-of-Service (QoS) guarantee. First, we consider the scheduling problem in cellular networks which support Device-to-Device Communications (D2D). In a D2D network, additional communication modes including orthogonal and non-orthogonal D2D communications make it very challenging to perform fair resource allocation while maximizing the system performance. Based on the Cumulative Distribution Function (CDF) scheduling approach, we propose two orthogonal scheduling policies that guarantee access fairness among all users while taking advantage of multi-user diversity and local D2D communications. For even higher spectral efficiency, spatial frequency reuse is proposed via our novel Group Fairness Scheduling (GFS) policy, that exploits both spatial frequency reuse and multiuser diversity in order to deliver marked improvements to system performance with perfect fairness among the users. Next, we examine the optimality of opportunistic scheduling under temporal fairness. In general, obtaining the optimal scheduling gain under user fairness or other QoS criteria for a heterogeneous environment is very difficult. Two main methods are proposed to obtain the optimal scheduling solutions under temporal fairness. In the first method, we derive linear program-based scheduling (LPS) algorithms using a window of past Channel State Information (CSI) to compute the scheduling decisions that can approach the optimal policy as the window size gets large. In the second method, we cast the scheduling problem as one of statistical classification and propose a novel supervised classification-based scheduling (SCS) framework for obtaining optimal scheduling decision boundaries. Finally, we address one of the key QoS aspects of opportunistic multiuser scheduling, the user service delay time. Keeping the service delay time under control while maximizing the scheduling gain subject to some fairness criterion is a very hard problem in general. In order to reduce the service delay, we introduce the concept of delay profile shaping. Based on this concept and large system approximations, we develop a novel delay reduction scheme, the Opportunistic Bernoulli Mixing (OBM) policy, which can support different user channel conditions and resource allocation requirements with an excellent performance/delay tradeoff.

Download or read book Adaptation and Cross Layer Design in Wireless Networks written by Mohamed Ibnkahla and published by CRC Press. This book was released on 2018-10-08 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive techniques play a key role in modern wireless communication systems. The concept of adaptation is emphasized in the Adaptation in Wireless Communications Series through a unified framework across all layers of the wireless protocol stack ranging from the physical layer to the application layer, and from cellular systems to next-generation wireless networks. Adaptation and Cross Layer Design in Wireless Networks is devoted to adaptation in the data link layer, network layer, and application layer. The book presents state-of-the-art adaptation techniques and methodologies, including cross-layer adaptation, joint signal processing, coding and networking, selfishness in mobile ad hoc networks, cooperative and opportunistic protocols, adaptation techniques for multimedia support, self –organizing routing, and tunable security services. It presents several new theoretical paradigms and analytical findings which are supported with various simulation and experimental results. Adaptation in wireless communications is needed in order to achieve high capacity and ubiquitous communications. The current trend in wireless communication systems is to make adaptation dependent upon the state of the relevant parameters in all layers of the system. Focusing on simplified cross layer design approaches, this volume describes advanced techniques such as adaptive resource management, adaptive modulation and coding, 4G communications, QoS, diversity combining, and energy and mobility aware MAC protocols. The first volume in the series, Adaptive Signal Processing in Wireless Communications (cat no.46012) covers adaptive signal processing at the physical layer.

Download or read book Opportunistic Scheduling with Limited Feedback in Wireless Communication Networks written by Mohammed E. Eltayeb and published by . This book was released on 2014 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: In multiuser networks, the base stations (BSs) rely on the channel state information (CSI) of the users to perform user scheduling and downlink transmissions. While the downlink channels can be easily estimated at all user terminals via a single broadcast, several key challenges are faced during uplink (feedback) transmissions. Firstly, the amount of air-time consumed during feedback transmission grows linearly with the number of users. This domination of the network resources by feedback traffic leads to increased scheduling delay and outdated CSI at the BS. Secondly , the fed back CSI is generally corrupted by the fading and noisy feedback channel. This could lead to transmission outages if the network scheduler bases its scheduling decisions on inaccurate CSI. These challenges make CSI acquisition arduous, if not impossible, in practice. In this research, we develop efficient scheduling algorithms that account for the feedback channel impairments of multiuser wireless networks. The proposed algorithms encompass both single and dual-hop wireless networks, and; permit the BS to obtain CSI with acceptable recovery guarantees under substantially reduced feedback overhead. More specifically, we consider feedback reduction for i) multiuser networks with single antenna base stations, ii) multiuser user networks with multi-antenna base stations, and iii) cooperative multiuser networks. Analytical and simulations results show that the proposed algorithms, together with the proposed feedback noise mitigation techniques, drastically reduce the feedback overhead, and achieve a rate close to that obtained by scheduling algorithms that require noiseless dedicated feedback from all users.

Download or read book High performance Scheduling Algorithms for Wireless Networks written by Shreeshankar Ravishankar Bodas and published by . This book was released on 2010 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of designing scheduling algorithm for multi-channel (e.g., OFDM-based) wireless downlink networks is considered, where the system has a large bandwidth and proportionally large number of users to serve. For this system, while the classical MaxWeight algorithm is known to be throughput-optimal, its buffer-overflow performance is very poor (formally, it is shown that it has zero rate function in our setting). To address this, a class of algorithms called iHLQF (iterated Heaviest matching with Longest Queues First) is proposed. The algorithms in this class are shown to be throughput-optimal for a general class of arrival/channel processes, and also rate-function optimal (i.e., exponentially small buffer overflow probability) for certain arrival/channel processes, where the channel-rates are 0 or 1 packets per timeslot. iHLQF however has higher computational complexity than MaxWeight (n4 vs. n2 computations per timeslot respectively). To overcome this issue, a new algorithm called SSG (Server-Side Greedy) is proposed. It is shown that SSG is throughput-optimal, results in a much better per-user buffer overflow performance than the MaxWeight algorithm (positive rate function for certain arrival/channel processes), and has a computational complexity (n2) that is comparable to the MaxWeight algorithm. Thus, it provides a nice trade-off between buffer-overflow performance and computational complexity. For multi-rate channel processes, where the channels can serve multiple packets per timeslot, new Markov chain-based coupling arguments are used to derive rate-function positivity results for the SSG algorithm. Finally, an algorithm called DMEQ is proposed and shown to be rate-function optimal for certain multi-rate channel scenarios, whose definition characterizes the sufficient conditions for rate-function optimality in this regime. These results are validated by both analysis and simulations.

Download or read book Scheduling and Congestion Control for Wireless and Processing Networks written by Libin Jiang and published by Springer Nature. This book was released on 2022-06-01 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, we consider the problem of achieving the maximum throughput and utility in a class of networks with resource-sharing constraints. This is a classical problem of great importance. In the context of wireless networks, we first propose a fully distributed scheduling algorithm that achieves the maximum throughput. Inspired by CSMA (Carrier Sense Multiple Access), which is widely deployed in today's wireless networks, our algorithm is simple, asynchronous, and easy to implement. Second, using a novel maximal-entropy technique, we combine the CSMA scheduling algorithm with congestion control to approach the maximum utility. Also, we further show that CSMA scheduling is a modular MAC-layer algorithm that can work with other protocols in the transport layer and network layer. Third, for wireless networks where packet collisions are unavoidable, we establish a general analytical model and extend the above algorithms to that case. Stochastic Processing Networks (SPNs) model manufacturing, communication, and service systems. In manufacturing networks, for example, tasks require parts and resources to produce other parts. SPNs are more general than queueing networks and pose novel challenges to throughput-optimum scheduling. We proposes a "deficit maximum weight" (DMW) algorithm to achieve throughput optimality and maximize the net utility of the production in SPNs. Table of Contents: Introduction / Overview / Scheduling in Wireless Networks / Utility Maximization in Wireless Networks / Distributed CSMA Scheduling with Collisions / Stochastic Processing networks

Download or read book Multiuser Scheduling Using Embedded Modulation in Wireless Networks microform written by Shermeen Nizami and published by Library and Archives Canada = Bibliothèque et Archives Canada. This book was released on 2004 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Efficient Scheduling under Delay Constraints for Wireless Networks written by Randal Berry and published by Springer Nature. This book was released on 2022-05-31 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Packet delay and energy consumption are important considerations in wireless and sensor networks as these metrics directly affect the quality of service of the application and the resource consumption of the network; especially, for a rapidly growing class of real-time applications that impose strict restrictions on packet delays. Dynamic rate control is a novel technique for adapting the transmission rate of wireless devices, almost in real-time, to opportunistically exploit time-varying channel conditions as well as changing traffic patterns. Since power consumption is not a linear function of the rate and varies significantly with the channel conditions, adapting the rate has significant benefits in minimizing energy consumption. These benefits have prompted significant research in developing algorithms for achieving optimal rate adaptation while satisfying quality of service requirements. In this book, we provide a comprehensive study of dynamic rate control for energy minimization under packet delay constraints. We present several formulations and approaches adopted in the literature ranging from discrete-time formulations and dynamic programming based solutions to continuous-time approaches utilizing ideas from network calculus and stochastic optimal control theory. The goal of this book is to expose the reader to the important problem of wireless data transmission with delay constraints and to the rich set of tools developed in recent years to address it. Table of Contents: Introduction / Transmission Rate Adaptation under Deadline Constraints / Average Delay Constraints

Download or read book Throughput Characterization and Algorithm Design in Wireless Networks written by Yang Yang and published by . This book was released on 2015 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: We next shift our focus from link-layer throughput to the MAC-layer throughput-region in multi-hop wireless networks. By assuming a binary interference relationship between links, we provide a thorough comparison of the throughput-regions that can be achieved under different combinations of multi-antenna techniques, such as MIMO multiplexing, multi-user MIMO and wireless full-duplex, from a degree-of-freedom perspective. Our results give clear guidelines on which multi-antenna architecture and traffic pattern could result in throughput improvement for one scheme over another. While the throughput-regions of different schemes may be compared, the adoption of new schemes raises challenges in the design of control algorithms that aim to support the entire throughput-region. Indeed, when each node is capable of wireless full-duplex cut-through transmission, the MAC-layer throughput-region is directly a function of the routing decision, leading to a strong coupling between routing and scheduling, which has not been seen in the traditional half-duplex network. Also, it is unclear how to dynamically form/change cut-through routes based on the traffic rates and patterns. In this dissertation, we introduce a novel method to characterize the interference relationship between links in the network with cut-through transmission, which decouples the routing decision with the scheduling decision and enables a seamless adaptation of traditional half-duplex algorithms into wireless networks with full-duplex cut-through capabilities.

Download or read book Wireless Algorithms Systems and Applications written by Lei Wang and published by Springer Nature. This book was released on 2022-11-17 with total page 679 pages. Available in PDF, EPUB and Kindle. Book excerpt: The three-volume set constitutes the proceedings of the 17th International Conference on Wireless Algorithms, Systems, and Applications, WASA 2022, which was held during October 28-30, 2022. The conference took place in Dalian, China.The 95 full and 62 short papers presented in these proceedings were carefully reviewed and selected from 265 submissions. The contributions in theoretical frameworks and analysis of fundamental cross-layer protocol and network design and performance issues; distributed and localized algorithm design and analysis; information and coding theory for wireless networks; localization; mobility models and mobile social networking; underwater and underground networks; vehicular networks; algorithms, systems, and applications of edge computing

Download or read book Energy and Spectrum Efficient Wireless Network Design written by Guowang Miao and published by Cambridge University Press. This book was released on 2015 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides the fundamental principles and practical tools needed to design next-generation wireless networks that are both energy- and spectrum-efficient.

Download or read book Channel Aware Scheduling and Resource Allocation with Cross Layer Optimization in Wireless Networks written by Sheu-Sheu Tan and published by . This book was released on 2013 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: We develop channel aware scheduling and resource allocation schemes with cross-layer optimization for several problems in multiuser wireless networks. We consider problems of distributed opportunistic scheduling, where multiple users contend to access the same set of channels. Instead of scheduling users to the earliest available idle channels, we also take the instantaneous channel quality into consideration and schedule the users only when the channel quality is sufficiently high. This can lead to significant gains in throughput compared to system where PHY and MAC layers are designed separately and the wireless fading channels are abstracted as time invariant, fixed rate channels for scheduling purposes. We first consider opportunistic spectrum access in a cognitive radio network, where a secondary user (SU) share the spectrum opportunistically with incumbent primary users (PUs). Similar to earlier works on distributed opportunistic scheduling (DOS), we maximize the throughput of SU by formulating the channel access problem as a maximum rate-of-return problem in the optimal stopping theory framework. We show that the optimal channel access strategy is a pure threshold policy, namely the SU decides to use or skip transmission opportunities by comparing the channel qualities to a fixed threshold. We further increase the spectrum utilization by interleaving SU's packets with periodic sensing to detect PU's return. We jointly optimize the rate threshold and the packet transmission time to maximize the average throughput of SU, while limiting interference to PU. Next, we develop channel-aware opportunistic spectrum access strategies in a more general cognitive radio network with multiple SUs. Here, we additionally take into account the collisions and complex interaction between SUs and sharing of resources between them. We derive strategies for both cooperative settings where SUs maximize their sum total of throughputs, as well as non-cooperative game theoretic settings, where each SU tries to maximize its own throughput. We show that the optimal schemes for both scenarios are pure threshold policies. In the non-cooperative case, we establish the existence of Nash equilibrium and develop best response strategies that can converge to equilibria, with SUs relying only on their local observations. We study the trade-off between maximal throughput in the cooperative setting and fairness in the non-cooperative setting, and schemes based on utility functions and pricing that mitigate this tradeoff. In addition to maximizing throughput and fair sharing of resources, it is important to consider network/scheduling delays for QoS performance of delay-sensitive applications. We study DOS under both network-wide and user-specific average delay constraints. We take a stochastic Lagrangian approach and characterize the corresponding optimal scheduling policies accordingly, and show that they have a pure threshold structure. Next, we consider the use of different types of channel quality information, i.e., channel state information (CSI) and channel distribution information (CDI) in the opportunistic scheduling design for MIMO ad hoc networks. CSI is highly dynamic in nature and provides time diversity in the wireless channel, but is difficult to track. CDI offers temporal stability, but is incapable of capturing the instantaneous channel conditions. We design a new class of cross-layer opportunistic channel access scheduling framework for MIMO networks where CDI is used in the network context to group the simultaneous transmission links for spatial channel access and CSI is used in the link context to decide when and which link group should transmit based on a pre designed threshold. We thereby reap the benefits of both the temporal stability of CDI and the time diversity of CSI. Finally, we consider a novel application of cross layer optimization for communication of progressive coded images over OFDM wireless fading channels. We first consider adaptive modulation based on the instantaneous channel state information. An algorithm is proposed to allocate power and constellation size at each subchannel by maximizing the throughput. We next consider both the variance and the average of the throughput when deciding the constellation size for adaptive modulation. Simulation results confirm that cross-layer optimization with adaptive modulation enhances system performance.

Download or read book On Distributed Scheduling for Wireless Networks with Time varying Channels written by Akula Aneesh Reddy and published by . This book was released on 2013 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless scheduling is a fundamental problem in wireless networks that involves scheduling transmissions of multiple users in order to support data flows with as high rates as possible. This problem was first addressed by Tassuilas and Ephremides, resulting in the celebrated Back-Pressure network scheduling algorithm. This algorithm schedules network links to maximize throughput in an opportunistic fashion using instantaneous network state information (NSI), i.e., queue and channel state knowledge across the entire network. However, the Back-Pressure (BP) algorithm suffers from various drawbacks - (a) it requires knowledge of instantaneous NSI from the whole network, i.e. feedback about time-varying channel and queue states from all links of the network, (b) the algorithm requires solving a global optimization problem at each time to determine the schedule, making it highly centralized. Further, Back-pressure algorithm was originally designed for wireless networks where interference is modeled using protocol interference model. As recent break-throughs in full-duplex communications and interference cancelation techniques provide greatly increased capacity and scheduling flexibility, it is not clear how BP algorithm can be modified to improve the data rates and reduce the delay. In this thesis, we address the drawbacks of Back-Pressure algorithm to some extent. In particular, our first work provides a new scheduling algorithm (similar to BP) that allows users to make individual decisions (distributed) based on heterogeneously delayed network state information (NSI). Regarding the complexity issue, in our second work, we analyze the performance of the greedy version of BP algorithm, known as Greedy Maximal Scheduling (GMS) and understand the effect of channel variations on the performance of GMS. In particular, we characterize the efficiency ratio of GMS in wireless networks with fading. In our third and fourth work, we propose and analyze new scheduling algorithms that can benefit from new advancements in interference cancelation techniques.

Download or read book Cross layer Resource Allocation and Scheduling in Wireless Multicarrier Networks written by Guocong Song and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The current dominate layered networking architecture, in which each layer is designed and operated independently, results in inefficient and inflexible resource use in wireless networks due to the nature of the wireless medium, such as time-varying channel fading, mutual interference, and topology variations. In this thesis, we focus on resource allocation and scheduling in wireless orthogonal frequency division multiplexing (OFDM) networks based on joint physical and medium access control (MAC) layer optimization. To achieve orders of magnitude gains in system performance, we use two major mechanisms in resource management: exploiting the time variance and frequency selectivity of wireless channels through adaptive modulation, coding, as well as packet scheduling and regulating resource allocation through network economics. With the help of utility functions that capture the satisfaction level of users for a given resource assignment, we establish a utility optimization framework for resource allocation in OFDM networks, in which the network utility at the level of applications is maximized subject to the current channel conditions and the modulation and coding techniques employed in the network. Although the nonlinear and combinatorial nature of the cross-layer optimization challenges algorithm development, we propose novel efficient dynamic subcarrier assignment (DSA) and adaptive power allocation (APA) algorithms that are proven to achieve the optimal or near-optimal performance with very low complexity. Based on a holistic design principle, we design max-delay-utility (MDU) scheduling, which senses both channel and queue information. The MDU scheduling can simultaneously improve the spectral efficiency and provide right incentives to ensure that all applications can receive their different required quality of service (QoS). To facilitate the cross-layer design, we also deeply investigate the mechanisms of channel-aware scheduling, such as efficiency, fairness, and stability. First, using extreme value theory, we analyze the impact of multiuser diversity on throughput and packet delay. Second, we reveal a generic relationship between a specific convex utility function and a type of fairness. Third, with rigorous proofs, we provide a method to design cross-layer scheduling algorithms that allow the queueing stability region at the network layer to approach the ergodic capacity region at the physical layer.