| 1. |
- Brunström, Anna, et al.
(författare)
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NEWCOM++ DR11.3: Final report on the activities and results of WPR11
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This document is the last deliverable of WPR.11 and presents an overview of the final activities carried out within the NEWCOM++ Workpackage WPR.11 during the last 18 months. We provide a description of the most consolidated Joint Research Activities (JRAs) and the main results so far obtained. We also address some considerations on the future activities which are expected to continue at the end of NEWCOM++
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| 2. |
- Lavén, Andreas
(författare)
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Anypath Routing for Reducing Latency in Multi-Channel Wireless Mesh Networks
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Increasing capacity in wireless mesh networks can be achieved by using multiple channels and radios. By using different channels, two nodes can send packets at the same time without interfering with each other. To utilize diversity of available frequency, a channel assignment scheme is required. Hybrid channel assignment is an interesting approach where at least one radio is tuned to a fixed channel for receiving and the remaining interfaces switch their channels dynamically in order to match the receiving channel at the receiving node.This provides full connectivity, but at the expense of introduced switching costs. Due to hardware limitations it is too costly to switch channels on a per packet basis.Instead, this thesis proposes an anypath routing and forwarding mechanism in order to allow each node along the route to select the best next hop neighbor on a per packet basis. The routing algorithm finds for each destination a set of next hop candidates and the forwarding algorithm considers the state of the channel switch operation when selecting a next hop candidate. Also, in order to allow latency-sensitive packets to be transmitted before other packets, latency-awareness has been introduced to distinguish e.g. VoIP flows from FTP traffic.The ideas have been implemented and tested using real-world experiments, and the results show a significant reduction in latency.
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| 3. |
- Lavén, Andreas, et al.
(författare)
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Latency Aware Anypath Routing and Channel Scheduling for Multi-Radio Wireless Mesh Networks
- 2014
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Ingår i: IEEE WCNC'14 Track 3 (Mobile and Wireless Networks). - : IEEE. - 9781479930838
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Konferensbidrag (refereegranskat)abstract
- Wireless mesh network (WMN), radio nodes that form a mesh topology, is an interesting architectural candidate for the future wireless Internet. A dense access network can rapidly be deployed at a reasonable cost because there is no need to wire the mesh access points. However, WMNs typically do not perform well with latency-sensitive data traffic, such as Voice over IP (VoIP), due to restricted bandwidth. In this paper, we present the design, implementation and evaluation of LA-APOLSR for hybrid WMNs, where mesh nodes have two radios; a fixed radio for receiving and a switchable radio which rapidly changes channels to send to neighbor nodes. The key novelty of our approach is to use anypath routing for latency-sensitive traffic while normal traffic is treated using single path routing. Also, we develop a novel queuing strategy which prioritizes latency-sensitive traffic. A detailed evaluation using KAUMesh, an in-house multi-radio wireless mesh testbed, shows a reduction in latency and packet loss for VoIP traffic without negatively impacting competing TCP background traffic.
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| 4. |
- Lavén, Andreas, et al.
(författare)
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Multi-Channel Anypath Routing in Wireless Mesh Networks
- 2010
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Ingår i: Proceedings of IEEE Globecom 2010. - : IEEE Press. - 9781424488636 ; , s. 196-201
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Konferensbidrag (refereegranskat)abstract
- Recently, wireless mesh networks have been proposed as a mechanism to provide alternative broadband wireless internet access. The usage of multiple radios transmitting at diverse frequency bands allows a significant increase in the capacity of such networks. However, popular Hybrid Channel Assignment strategies, which use a fixed interface for receiving and a switchable interface for transmitting to neighbor nodes, suffer from large delay and jitter due to the accumulated switching overhead over multiple hops. In this paper, we propose a novel routing mechanism for such hybrid multi-radio multichannel mesh networks based on the anypath paradigm. In our approach, the routing layer maintains for each destination at each hop a set of candidate forwarders, where each neighbor is tuned to a different channel. A novel layer 2.5 forwarding and scheduling algorithm decides then for each packet individually, which actual neighbor to forward the packet to, in order to minimize the overall delay. We implemented the selected approach using extensions to OLSR. An evaluation in KAUMesh test bed shows for specific scenarios that AP-OLSR reduces average delay with up to 70% compared to standard OLSR while also reducing both average and maximum jitter by 60% and 45% respectively.
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| 5. |
- Lavén, Andreas, et al.
(författare)
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Performance Evaluation of the Anypath Routing and Forwarding Mechanism AP-OLSR
- 2013
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Ingår i: MSWiM '13 Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450323536 ; , s. 81-90
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Wireless mesh networks (WMNs) consist of several small routers relaying packets wirelessly toward the destination or the Internet. A dense deployment enables the rapid creation of wireless access networks at a reasonable cost. The capacity of a wireless mesh network can be increased by using a diverse set of channels to allow simultaneous transmissions without causing interference. An interesting approach is to use one fixed wireless network interface for receiving and at least one switchable interface for sending. However, such a channel assignment suffers from switching overhead.In order to minimize the channel switching latency, we have developed a novel packet routing and forwarding strategy, AP-OLSR, which uses multiple next hop candidates tuned to different channels. When forwarding a packet, nodes pick the neighbor which is on a channel that gives a good balance between local switching overhead and global path quality.In this paper, we present a thorough evaluation of AP-OLSR with scenarios involving both single and multiple gateways, as well as single and competing flows. The evaluation shows that AP-OLSR can improve performance in both latency and throughput.
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| 6. |
- Abdollahi, Kamran, et al.
(författare)
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Improving Performance of On Demand Multicast Routing by deleting lost join query packet
- 2010
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Ingår i: Proceedings of The Sixth Advanced International Conference on Telecommunications - AICT 2010. - : IEEE conference proceedings. - 9780769540214 ; , s. 316-322
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Konferensbidrag (refereegranskat)abstract
- A Mobile ad hoc network is a collection of wireless nodes that dynamically organize themselves to form a network without the need for any fixed infrastructure or centralized administration. The network topology dynamically changes frequently in an unpredictable manner since nodes are free to move. Support for multicasting is essential in such environment as it is considered to be an efficient way to deliver information from source nodes to many client nodes. A problem with multicast routing algorithms is their efficiency as their forwarding structure determines the overall network resource consumption makes them significantly less efficient than unicast routing algorithms. In this research, we improve the performance of the popular ODMRP multicast routing protocol by restricting the domain of join query packets, which have been lost. This is achieved by augmenting the join query packets with minimum extra information (one field), which denotes the number of the visited node from previous forwarding group. Simulation results show, that our mechanisms significantly reduce the control traffic and thus the overall latency and power consumption in the network.
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| 7. |
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| 8. |
- Brajdic, Agata, et al.
(författare)
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Quality of Experience based optimization of heterogeneous multimedia sessions in IMS
- 2011
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Ingår i: Proceedings of Baltic Congress on Future Internet Communications. - : IEEE conference proceedings. - 9781424485116 ; , s. 25-32
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Konferensbidrag (refereegranskat)abstract
- For delivering multimedia services over (wireless) networks it is important that the mechanisms which negotiate and optimize content delivery under resource constraints take into account user perceived quality in order to improve user satisfaction. Within the scope of the IP Multimedia Subsystem (IMS) architecture a novel application server may be added which handles multi-user multi-flow Quality of Experience (QoE) negotiation and adaptation for heterogeneous user sessions. Based on a mathematical model, which takes into account the characteristics of audio, video and data sessions for QoE optimization, we develop several optimization algorithms to be used by the application server to maximize overall user defined QoE parameters for all ongoing multimedia sessions, subject to network resource constraints. Our results show that a greedy based approach provides a reasonable compromise in terms of run-time and sub-optimality for the overall QoE based resource allocations.
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| 9. |
- Castro C, Marcel, 1978-, et al.
(författare)
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Peer-to-Peer Selection and Channel Assignment for Wireless Mesh Networks
- 2011
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Konferensbidrag (refereegranskat)abstract
- Wireless mesh networks are an emerging paradigm for future broadband wireless access networks, with manyapplication areas ranging from content distribution over community networking and providing backhaul networking for sensor devices. In wireless mesh networks, clients connect to wireless routers which are equipped with one or more wireless cards and relay the packets over the wireless links towards internetgateways or the destination. Peer-to-Peer applications are an important class of applications which contributes nowadays to the majority of internet traffic. Therefore, it is important to provide high capacity in the mesh network to support them. However, the capacity of wireless mesh networks depends on many factors such as network topology and size, traffic volume and pattern, interfaces per node and channel assignment scheme used, modulation schemes, routing approaches, etc. In this paper, we develop an analytical framework which allows to estimate theachievable capacity of a wireless mesh network when peer-to-peer applications download many flows simultaneously. The model is based on the collision domain concept and incorporates various channel assignment, replication and peer selection strategies. We investigate the achievable capacity for various scenarios and study the impact of different parameters such as the number of channels or radios used
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| 10. |
- Cavalcanti de Castro, Marcel, 1978-, et al.
(författare)
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BestPeer : A Load-aware Multi-path Peer Selection for Wireless Mesh Networks
- 2012
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Ingår i: 2012 IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM). - : IEEE Press. - 9781467312387
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Konferensbidrag (refereegranskat)abstract
- In this paper we study the interactions between peer selection, routing and channel assignment while deploying Peer-to-Peer (P2P) systems over multi-channel multi-radio Wireless Mesh Networks (WMNs). In particular we propose Bestpeer, a novel peer selection algorithm for WMNs which incorporates a cross-layer path load metric and integrates multi-path load balancing capability throughout the P2P download process in order to achieve faster resource disseminations. By comparing Bestpeer with BitTorrent through extensive simulations, we show that we can reduce the time to disseminate a resource by up to 40 %. The key mechanism used by Bestpeer to increase performance in WMNs is the effective exploitation of cross-layer information made available from the routing and channel assignment during the peer selection process in order to balance the load along high capacity paths
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