43 research outputs found

    Analyzing Multi-Channel Medium Access Control Schemes With ALOHA Reservation

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    In order to improve the throughput performance of Medium Access Control (MAC) schemes in wireless communication networks, some researchers proposed to divide a single shared channel into several sub-channels: one as control subchannel and the others as data sub-channels. In this paper, we analyze and evaluate the maximum achievable throughput of a class of generic multi-channel MAC schemes that are based on the RTS/CTS (Ready-To-Send/Clear-To-Send) dialogue and on ALOHA contention resolution. We study these multichannel MAC schemes under two split-channel scenarios: the fixed-total-bandwidth scenario and the fixed-channel-bandwidth scenario. In the fixed-total-bandwidth scenario, we show that the throughput of the multi-channel MAC schemes is inferior to that of the corresponding single-channel MAC scheme, which sends the RTS/CTS packets and DATA packets on a single shared channel. For the fixed-channel-bandwidth scenario, where CDMA or similar techniques can be applied, we derive the optimal number of the data sub-channels that maximizes the throughput. The analytical framework that we derive in this paper can also be used to evaluate other contention resolution technique, when the average contention period is known

    Channel-access and routing protocols to utilize multiple heterogeneous channels for ad hoc networks

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    In this thesis, we consider a multi-channel ad hoc network employing frequency-agile radios that utilize direct-sequence spread-spectrum signaling. Two of the key distributed protocols for this type of network control channel access and routing. The channel-access protocol is responsible for controlling access to the channels available to the terminals in the network, and the routing protocol determines how packets are forwarded among the terminals in the network. To achieve reliable and efficient network performance, these protocols should cooperate with one another and take advantage of the multiple channels available to the network. In this thesis, we investigate a number of channel-access strategies for selecting a channel as well as various channel metrics to be used with routing. For our channel-access protocol, one channel is designated the control channel and is used to reserve access to one of the traffic channels. The channel-access protocol selects the traffic channel for a data packet transmission by examining the characteristics of the different traffic channels. New channel metrics are proposed to characterize the channels, and the metric values are used to assign a link resistance value for a link. Least-resistance routing utilizes the link resistances to calculate routes. The performance of the channel metrics for the routing protocol and the channel-access strategies are examined with a discrete-event simulation. From our investigations, we show that a jointly designed protocol that coordinates the channel-access strategies with the channel metrics results in network performance that is better than traditional channel-access and minimum-hop routing protocols

    Analyzing split channel medium access control schemes,”

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    Abstract: In order to improve the throughput performance of Medium Access Control (MAC) schemes in wireless communication networks, some researchers proposed to divide a single shared channel into several subchannels: one as control sub-channel and the others as data sub-channels. In this paper, we analyze and evaluate the maximum achievable throughput of a class of generic multi-channel MAC schemes that are based on the RTS/CTS (Ready-To-Send/Clear-To-Send) dialogue and on ALOHA contention resolution. We study these multichannel MAC schemes under two split-channel scenarios: the fixed-total-bandwidth scenario and the fixed-channel-bandwidth scenario. In the fixed-total-bandwidth scenario, we show that the throughput of the multi-channel MAC schemes is inferior to that of the corresponding single-channel MAC scheme, which sends the RTS/CTS packets and DATA packets on a single shared channel. For the fixed-channel-bandwidth scenario, where CDMA or similar techniques can be applied, we derive the optimal number of the data subchannels that maximizes the throughput. The analytical framework that we derive in this paper can also be used to evaluate other contention resolution technique, when the average contention period is known. Index Terms: medium access control, MAC, shared channel, multiple channels, ALOHA, contention resolution, RTS/CTS dialogue Article: I. INTRODUCTION In wireless communication networks, Medium Access Control (MAC) schemes are used to manage the access of active nodes to a shared channel Even though there are many multi-channel MAC schemes proposed in the technical literature, to the best of our knowledge, systematic comparison of these multi-channel MAC schemes with the corresponding single-channel schemes is not available except i

    A cross-layer approach to increase spatial reuse and throughput for ad hoc networks

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    Ad hoc networks employing adaptive-transmission protocols can alter transmission parameters to suit the channel environment. Channel-access mechanisms are used to govern temporal use of the transmission medium amongst nodes. Effective operation of a channel-access mechanism can improve the ability of an adaptive-transmission protocol to accommodate changing channel conditions. The interoperability of these two mechanisms motivates cross-layer design of adaptive-transmission protocols. In this thesis we examine the integration of a new channel-access mechanism with a physical-layer adaptive-transmission protocol to create a cross-layer protocol with enhanced capabilities. We derive specific physical-layer measurements which are used to control channel-access behavior in a distributed manner. We propose a distributed heuristic using cross-layer information to drive a channel-access protocol which works in conjunction with an adaptive-transmission protocol. We show that the new protocol outperforms statically configured transmission protocols as well as protocols which act independently of cross-layer enhancements

    Protocol Design and Performance Evaluation of Wake-up Radio enabled IoT Networks

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