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Exploiting multi-channel diversity in spectrum-agile networks
- Proceedings of INFOCOM
, 1921
"... Abstract—Recently, spectrum-agile (SA) networks have been recognized as a viable solution to the spectrum-scarcity problem in wireless communications. In SA networks, secondary (unli-censed) users are allowed to opportunistically utilize idle licensed spectrum bands, thus improving spectrum utilizat ..."
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Abstract—Recently, spectrum-agile (SA) networks have been recognized as a viable solution to the spectrum-scarcity problem in wireless communications. In SA networks, secondary (unli-censed) users are allowed to opportunistically utilize idle licensed spectrum bands, thus improving spectrum utilization efficiency and accommodating more users and applications. We take a two-step approach to the problem of maximizing the throughput of an SA network. The first step is to determine a subset of “candidate ” channels that a secondary device will consider for its channel-switching. The candidate channels are selected based on their estimated utilization. We then propose channel-aware switching to determine when and where to switch to, among the candidate channels. Wireless channels are assumed to experience independent Rayleigh fading, and modeled with a finite-state Markov channel (FSMC) model. Our evaluation results show that the proposed channel-aware switching scheme significantly outperforms the traditional forced-switching scheme in terms of average throughput. I.
Requirements of an open platform for cognitive networks experiments
- in 3rd IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks
, 2008
"... Abstract — Experimental research on networks of cognitive radios has been hindered by the lack of open, affordable cognitive radios and associated software that are capable of operating with the full network protocol stack. In this paper, we describe our vision of the building blocks needed to creat ..."
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Abstract — Experimental research on networks of cognitive radios has been hindered by the lack of open, affordable cognitive radios and associated software that are capable of operating with the full network protocol stack. In this paper, we describe our vision of the building blocks needed to create an open platform for cognitive network experimentation and prototyping. These include mechanisms for distributed spectrum sensing, a MAC protocol tailored to dynamic spectrum access, and interface languages for cognitive networks.
MULTI CHANNEL MAC FOR WIRELESS SENSOR NETWORKS
"... In this work, Sensor Multi Channel (SMC) Medium Access Control (MAC) has been proposed for wireless sensor networks. The SMC MAC uses a dedicated control channel and multiple data channels. The effective solution for the multi channel hidden terminal problem and missing receiver problem has been pro ..."
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In this work, Sensor Multi Channel (SMC) Medium Access Control (MAC) has been proposed for wireless sensor networks. The SMC MAC uses a dedicated control channel and multiple data channels. The effective solution for the multi channel hidden terminal problem and missing receiver problem has been proposed in this work. The performance of the SMC MAC has been compared with that of the single channel CSMA/CA MAC by taking the throughput and latency as performance metrics. It has been shown that the multi channel MAC gives high throughput and less latency in high traffic conditions.
Distributed On Demand Channel Selection in Multi Channel, Multi Interface Wireless Mesh Networks
"... Abstract—In this paper we present a protocol performing on demand distributed channel selection in multi channel, multi interface wireless mesh networks, based on the exchange of control messages. The link based channel reservation happens almost instantly when data traffic is sent through the netwo ..."
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Abstract—In this paper we present a protocol performing on demand distributed channel selection in multi channel, multi interface wireless mesh networks, based on the exchange of control messages. The link based channel reservation happens almost instantly when data traffic is sent through the network, and does not require long-term traffic profiles or measurements. The protocol is both simulated and implemented using the IEEE 802.11b/g protocol. We show that in a raster topology, the protocol successfully optimizes the local spectrum usage at 87% of the nodes, and that globally, an equal amount of links is allocated to each of the channels used for the transport of data packets. I.
C-MAC: A Cognitive MAC Protocol for Multi- Channel Wireless Networks
"... Abstract – A number of algorithmic and protocol assumptions taken for granted in the design of existing wireless communication technologies need to be revisited in extending their scope to the new cognitive radio (CR) paradigm. The fact that channel availability can rapidly change over time and the ..."
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Abstract – A number of algorithmic and protocol assumptions taken for granted in the design of existing wireless communication technologies need to be revisited in extending their scope to the new cognitive radio (CR) paradigm. The fact that channel availability can rapidly change over time and the need for coordinated quiet periods in order to quickly and robustly detect the presence of incumbents, are just some of the examples of the unique challenges in protocol and algorithm design for CR networks and, in particular, in the medium access control (MAC) layer. With this in mind, in this paper we introduce a novel cognitive MAC (C-MAC) protocol for distributed multi-channel wireless networks. C-MAC operates over multiple channels, and hence is able to effectively deal with, among other things, the dynamics of resource availability due to primary users and mitigate the effects of distributed quiet periods utilized for primary user signal detection. In C-MAC, each channel is logically divided into recurring superframes which, in turn, include a slotted beaconing period (BP) where nodes exchange information and negotiate channel usage. Each node transmits a beacon in a designated beacon slot during the BP, which helps in dealing with hidden nodes, medium reservations, and mobility. For coordination amongst nodes in different channels, a rendezvous channel (RC) is employed that is decided dynamically and in a totally distributed fashion. Among other things, the RC is used to support network-wide multicast and broadcast which are often neglected in existing multi-channel MAC protocols. We present promising performance results of C-MAC. We also describe our efforts to implement features of C-MAC in a real CR prototype with Atheros chipset, which currently includes the spectrum sensing module and preliminary features of C-MAC. I.
Unified Synchronously Scheduled Routing for Static Multi-hop Wireless Networks Abstract
"... (USSR): a combined pseudo-MAC and Routing layer protocol for commodity 802.11 static multi-hop networks. Considering a community wireless scenario, our approach leverages a centralized network “gateway ” to intelligently route traffic through the broadcast wireless mesh. The centralized gateway sche ..."
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(USSR): a combined pseudo-MAC and Routing layer protocol for commodity 802.11 static multi-hop networks. Considering a community wireless scenario, our approach leverages a centralized network “gateway ” to intelligently route traffic through the broadcast wireless mesh. The centralized gateway schedules nodes on non-overlapping channels in order to minimize inter-node interference. This approach increases the overall capacity of the networks and allows for improved multi-hop throughput and fairness for nodes several hops from the gateway compared to traditional routing protocols. We make an argument for why the increased complexity and overhead is reasonable and demonstrate that such an approach can provide improvements in properties central to making multi-hop wireless networks more useful in real-world deployments. 1
