Hybrid Channel Access Scheduling in Ad Hoc Networks

Hybrid Channel Access Scheduling in Ad Hoc Networks
Author:
Publisher:
Total Pages: 13
Release: 2002
Genre:
ISBN:

We present the hybrid activation multiple access (HAMA) protocol for ad hoc networks. Unlike previous channel access scheduling protocols that activate either nodes or links only, HAMA is a node-activation channel access protocol that also maximizes the chance of link activations using time- and code-division schemes. HAMA only requires identifiers of the neighbors within two hops from each node to schedule channel access. Using this neighborhood information, each node determines whether to transmit in the current time slot on a dynamically assigned spreading code. A neighbor protocol supplements HAMA with up-to-date two-hop neighborhood information by reliably propagating the one-hop neighbor updates through a novel random access technique. The throughput and delay characteristics of HAMA in randomly-generated multihop wireless networks are studied by analyses and simulations. The results of the analyses show that HAMA achieves higher channel utilization in ad hoc networks than a distributed scheduling scheme based on node activation, similar throughout as a well-known scheduling algorithm based on complete topology information, and much higher throughout than the ideal CSMA and CSMA/CA protocols.

NETWORKING 2007. Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet

NETWORKING 2007. Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet
Author: Ian F. Akyildiz
Publisher: Springer Science & Business Media
Total Pages: 1278
Release: 2007-04-27
Genre: Computers
ISBN: 3540726055

This book constitutes the refereed proceedings of the 6th International IFIP-TC6 Networking Conference, NETWORKING 2007, held in Atlanta, GA, USA in May 2007. The 99 revised full papers and 30 poster papers were carefully reviewed and selected from 440 submissions. The papers are organized in topical sections on ad hoc and sensor networks: connectivity and coverage, scheduling and resource allocation, mobility and location awareness, routing, and key management; wireless networks: mesh networks, mobility, TCP, MAC performance, as well as scheduling and resource allocation; next generation inte.

Throughput and Fairness in A Hybrid Channel Access Scheme for Ad Hoc Networks

Throughput and Fairness in A Hybrid Channel Access Scheme for Ad Hoc Networks
Author:
Publisher:
Total Pages: 7
Release: 2003
Genre:
ISBN:

A novel hybrid channel access scheme that combines sender-initiated and receiver-initiated collision-avoidance handshakes is proposed for multi-hop ad hoc networks. The scheme is based on the observation that a receiver-initiated scheme is more appropriate when receivers are more knowledgeable of the contention around themselves and can compete for the channel more effectively. By adaptively sharing the burden of initiating the collision-avoidance handshake between the nodes that experience different levels of contention, better fairness may be achieved with almost no degradation in throughput. An attractive feature of the new scheme is that it is a simple extension to the existing IEEE 802.11 MAC protocol, and it maintains compatibility with the standard. The new scheme involves adding very simple queue management and book-keeping work mechanisms. Simulation experiments of the IEEE 802.11 MAC protocol and the new scheme show that, although the proposed hybrid scheme does not solve the fairness problem conclusively, it does alleviate the fairness problem in some cases without sacrificing much throughput and simplicity. The difficulty of improving fairness for TCP-based flows is demonstrated. A promising topic for future work consists of combining the new hybrid scheme with some proposed mechanisms that try to approximate fair queueing for ad hoc networks to achieve some QoS assurances. Without explicit information exchange among nodes, the fairness problem cannot be solved conclusively.

Medium Access Control in Wireless Networks

Medium Access Control in Wireless Networks
Author: Hongyi Wu
Publisher: Nova Publishers
Total Pages: 662
Release: 2008
Genre: Computers
ISBN: 9781600219443

Wireless technologies and applications are becoming one of the fastest growing and most promising areas in recent years. To accommodate data transmission by multiple stations sharing the scarce wireless bandwidth, a medium access control (MAC) protocol plays a crucial role in scheduling packet transmission fairly and efficiently. The emerging wireless networks, such as ad-hoc networks, sensor networks or mesh networks, are mostly multi-hop based and in distributed manner, which brings a lot of problems and challenges in designing fine-tuned MAC protocols tailored for modern wireless network. In this book, the authors give complete and in-depth overviews to the classic medium access control algorithms and the related protocols, as well as their applications in various wireless data networks especially the most successful Wireless Local Area Networks (WLAN). The book consists of three major parts. Part I of this book, including Chapters 1-7, is emphasising on the fundamentals of medium access control algorithms and protocols. Chapter 1 provides an introduction to the wireless networks, such as overview of wireless networks, problems and challenges of the wireless networks, and the classifications of MAC protocols as well as the performance metrics. Chapter 2 introduces important collision resolution algorithms applied in medium access controls, for example, the splitting algorithm and the backoff algorithm. Chapter 3 reviews the hybrid access control algorithms that combine both contention and allocation schemes. A series of important collision avoidance schemes are introduced in Chapters 4-7 respectively, with a specific design goal covered in each chapter. Chapter 4 focuses on the multi-channel MAC protocols for collision avoidance; Chapter 5 introduces the concepts of power control and power management in medium access control and how they can be applied in MAC protocol design; Chapter 6 presents how to provide Quality-of- Service (QoS) to multimedia wireless networks, in either centralised or distributed manner; and Chapter 7 explains how the smart antennas can be applied in the medium access control to provide high channel throughput and low packet collision.

A New Hybrid Channel Access Scheme for Ad Hoc Networks

A New Hybrid Channel Access Scheme for Ad Hoc Networks
Author:
Publisher:
Total Pages: 6
Release: 2002
Genre:
ISBN:

Many contention-based channel access schemes have been proposed for multi-hop ad hoc networks in the recent past, and they can be divided into two categories, sender-initiated and receiver-initiated, according to the collision avoidance handshake in use. The sender-initiated scheme is adopted in the IEEE 802.11 Medium Access Control (MAC) protocol, which is by far the most popular and studied protocol. However, the IEEE 802.11 MAC protocol can experience serious fairness problems due to location-dependent contention and the binary exponential backoff it uses. On the other hand, a receiver-initiated collision avoidance handshake is more effective at the receiver's side. Hence, the authors propose a hybrid channel access scheme that combines both sender-initiated and receiver-initiated collision avoidance schemes. The new scheme involves only some additional queue management and book-keeping work while maintaining compatibility with the existing IEEE 802.11 protocol. Simulation experiments show that the new scheme is very effective, as it can achieve much better fairness than the original sender-initiated scheme with almost no degradation in throughput. The hybrid scheme also eliminates the need for a good traffic estimator, which is usually mandatory in pure receiver-initiated schemes.

Channel Access Scheduling in Ad Hoc Networks with Unidirectional Links

Channel Access Scheduling in Ad Hoc Networks with Unidirectional Links
Author:
Publisher:
Total Pages: 11
Release: 2001
Genre:
ISBN:

A new family of collision-free channel access protocols for ad hoc networks with unidirectional links is introduced. These protocols are based on a distributed contention resolution algorithm that operates at each node based on the list of direct contenders (one-hop neighbors or incident links) and indirect interferences (two-hop neighbors and related links). Depending on the activation scheme (node activation or link activation), a network node uses the identifiers of its neighbors one and two hops away to elect deterministically one or multiple winners for channel access in each contention context (e.g., a time slot or a frequency band). The protocols are shown to be fair and capable of achieving maximum utilization of the channel bandwidth. The delay and throughput characteristics of the channel access protocols is studied by simulations.

Distributed Dynamic Channel Access Scheduling for Ad Hoc Networks

Distributed Dynamic Channel Access Scheduling for Ad Hoc Networks
Author:
Publisher:
Total Pages: 35
Release: 2002
Genre:
ISBN:

Three types of collision-free channel access protocols for ad hoc networks are presented. These protocols are derived from a novel approach to contention resolution that allows contending entities to elect one or multiple winners for channel access in any given contention context (e.g., a time slot) in a distributed fashion. In multihop wireless networks, the only required information for each entity is the identifiers of its neighbors one and two hops away. The new protocols are shown to be fair and capable of achieving maximal utilization of the channel bandwidth. The delay and throughput characteristics of the contention resolution algorithms are analyzed, and the performance of the three types of channel access protocols is studied by simulations and compared with that of optimal static scheduling algorithms.

Networked Systems

Networked Systems
Author: Mohammed-Amine Koulali
Publisher: Springer Nature
Total Pages: 323
Release: 2022-09-27
Genre: Computers
ISBN: 3031174364

This book constitutes the revised selected papers of the 10th International Conference on Networked Systems, NETYS 2022, held as virtual event, in May 17–19, 2022. The conference was held virtually due to the COVID-19 crisis. The 18 full papers and 2 short papers presented were carefully reviewed and selected from 100 submissions. The scope of the conference covers all aspects related to the design and the development of these systems, including multi-core architectures, Concurrent and distributed algorithms, parallel/concurrent/distributed programming, distributed databases, big data applications and systems, cloud systems, networks, security, and formal verification. They were organized in topical sections as follows: Distributed System; Networking; Verification; Security.

Cognitive Wireless Communication Networks

Cognitive Wireless Communication Networks
Author: Ekram Hossain
Publisher: Springer Science & Business Media
Total Pages: 459
Release: 2007-10-23
Genre: Technology & Engineering
ISBN: 0387688323

This book provides a unified view on the state-of-the-art of cognitive radio technology. It includes a set of research and survey articles featuring the recent advances in theory and applications of cognitive radio technology for the next generation (e.g., fourth generation) wireless communication networks. The contributed articles cover both the theoretical concepts (e.g., information-theoretic analysis) and system-level implementation issues.