A multichannel relay MAC protocol for IEEE 802.11 wireless LANs

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109605/1/dac2526.pd

AMNP: ad hoc multichannel negotiation protocol for multihop mobile wireless networks

Abstract — Increasing the capacity of wireless communication is an important and urgent research area, which has attracted more attentions. One of potential solutions is to divide the radio spectrum into several independent radio channels, which can be operated and accessed by all nodes within their radio transmission range simultaneously. Many solutions adopt mul-tiple transceivers to fulfill this goal. However, these solutions are short in implementation and may increase the prime cost of the device since most wireless devices only equip one single transceiver. Moreover, with a few exceptions, most researchers have emphasized centralized resource allocation algorithms for cellular systems where the base station keeps track of the requirements of the various users and is thus responsible for the management of network resources. Nevertheless, on the other hand, a multihop mobile ad hoc network (MANET) is generally configured as peer-to-peer networks with no centralized hubs or controllers to coordinate channel allocations. Therefore, in this paper, we proposed a multichannel medium access control (MAC) protocol, named ad hoc multichannel negotiation protocol (AMNP), for multichannel transmission by using the distributed fashion. We address the issue of distributed resource allocation for multihop MANETs by presenting an AMNP that builds on the multichannel request-to-send/clear-to-send (MRTS/MCTS) bandwidth reservation mechanism under the constraint of a single transceiver. Besides, to conquer the problem of broadcast transmissions in multichannel environment under the constrain of one single transceiver, we further design a broadcast announce-ment scheme for AMNP. Moreover, an enhancement version of AMNP called AMNP with channel scheduling (AMNP/s) is also introduced to improve the channel utilization. We show via simulations that AMNP/s provides a higher throughput compared to its single channel counterpart by promoting simultaneous transmissions in different channels. Simulation results also show that the proposed AMNP/s derives higher performance than other multichannel transmission schemes, which equip multiple transceivers

Performance analysis of RTS/CTS protocol over Basic Access in wireless networks

The CSMS/CA protocol is employed in wireless networks in order to overcome issues such as the hidden node problem. This mechanism is expected to handle collisions better using the RTS/CTS mechanism. This method will allow a participating node to take part in communication only if it receives a "Clear to Send" message and thereby, theoretically "avoiding" collision. The objective of this paper is to analyse the improvement that the RTS/CTS mode brings over the Basic Access mode. The paper presents the study of wireless nodes within a specific area with increasing node concentration to verify the performance impact of a protocol in wireless networks, particularly when the node concentration increases

An Adaptive Common Control Channel MAC with Transmission Opportunity in IEEE 802.11ac

Spectral utilization is a major challenge in wireless ad hoc networks due in part to using limited network resources. For ad hoc networks, the bandwidth is shared among stations that can transmit data at any point in time. It  is important to maximize the throughput to enhance the network service. In this paper, we propose an adaptive multi-channel access with transmission opportunity protocol for multi-channel ad hoc networks, called AMCA-TXOP. For the purpose of coordination, the proposed protocol uses an adaptive common control channel over which the stations negotiate their channel selection based on the entire available bandwidth and then switch to the negotiated channel. AMCA-TXOP requires a single radio interface so that each station can listen to the control channel, which can overhear all agreements made by the other stations. This allows parallel transmission to multiple stations over various channels, prioritizing data traffic to achieve the quality-of-service requirements. The proposed approach can work with the 802.11ac protocol, which has expanded the bandwidth to 160 MHz by channel bonding. Simulations were conducted to demonstrate the throughput gains that can be achieved using the AMCA-TXOP protocol. Moreover, we compared our protocol with  the IEEE 802.11ac standard protocols

Multi-channel Utilization Algorithms for IEEE 802.15.4 based Wireless Network: A Survey

In the pass years, IEEE 802.15.4 based Wireless Sensor Networks (WSNs) have received great attention and have been employed in many areas such as inventory checking, local monitoring and alarming etc. One of the key issues affecting WSN's system performance is interference caused by devices operating with the same or different standards on the overlapping frequency within the 2.4 GHz ISM band. This paper addresses the coexistence problem, which is the key motivation for the necessity of flexible channel usage. A review of existing approaches being proposed to date supporting multi-channel utilization in IEEE 802.15.4 based WSNs is categorized and discussed. The paper also presents major functionalities needed in implementing multi-channel utilization

Throughput optimization strategies for large-scale wireless LANs

Thanks to the active development of IEEE 802.11, the performance of wireless local area networks (WLANs) is improving by every new edition of the standard facilitating large enterprises to rely on Wi-Fi for more demanding applications. The limited number of channels in the unlicensed industrial scientific medical frequency band however is one of the key bottlenecks of Wi-Fi when scalability and robustness are points of concern. In this paper we propose two strategies for the optimization of throughput in wireless LANs: a heuristic derived from a theoretical model and a surrogate model based decision engine

Medium Access Control Protocols for Ad-Hoc Wireless Networks: A Survey

Studies of ad hoc wireless networks are a relatively new field gaining more popularity for various new applications. In these networks, the Medium Access Control (MAC) protocols are responsible for coordinating the access from active nodes. These protocols are of significant importance since the wireless communication channel is inherently prone to errors and unique problems such as the hidden-terminal problem, the exposed-terminal problem, and signal fading effects. Although a lot of research has been conducted on MAC protocols, the various issues involved have mostly been presented in isolation of each other. We therefore make an attempt to present a comprehensive survey of major schemes, integrating various related issues and challenges with a view to providing a big-picture outlook to this vast area. We present a classification of MAC protocols and their brief description, based on their operating principles and underlying features. In conclusion, we present a brief summary of key ideas and a general direction for future work