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Incremental relaying (IR) is known to improve the spectral efficiency of cooperative communication by using the destination feedback. In IR, the relay nodes are employed to assist the source transmission only if it is failed. When the relay nodes perform demodulate-and-forward (DmF), all of them are eligible to forward the source information. This is different from decode-and-forward (DF), where only...
We propose in [1] a collaborative broadcast scheme for wireless networks, which applies the Uncoordinated Frequency Hopping (UFH) technique to counteract jamming and exploits node cooperation to enhance broadcast efficiency. In this scheme, some nodes that already obtain the broadcast message are selected to relay the message to other nodes. In this paper, we extend the study to the generalized multihop...
Message Ferrying is a mobility assisted scheme in which a special node, called a message ferry, is tasked with delivering data among a set of disconnected wireless nodes. One key challenge for such scheme is to design the ferry route in a way that improves certain network characteristics such as average data delivery delay or data loss ratio. Previous work has optimized ferry travel time, rather than...
This paper proposes a Markov model for analyzing the performance of periodic broadcast in vehicular ad hoc networks (VANETs). Since there is no packet retransmission in broadcast, we only consider a one-dimensional Markov model. In the proposed model, we assume that the traffic condition is unsaturated and introduce a state to represent the situation when there is no packet waiting for transmission...
The design of random media access control (MAC) renews great attention for emerging challenged wireless environments where the propagation delay is long and varying, such as satellite or underwater acoustic sensor networks. In these environments, the existing MAC solutions based on slotted transmissions, carrier sensing, or channel reservation by control packets are no longer favorable or even feasible...
With the tremendous increase in mobile data traffic, system capacity considerations are no longer the primary and only concern to optimize for in cellular networks. The step increase in utilization of cellular networks not only has shorten the recharging cycle of mobile terminals but has further caused a considerable rise in the operators' energy bill. It has therefore become imperative for the sustainable...
We consider the problem of energy-efficient transmission in multi-flow multihop cooperative wireless networks. Although the performance gains of cooperative approaches are well known, the combinatorial nature of these schemes makes it difficult to design efficient polynomial-time algorithms for joint routing, scheduling and power control. This becomes more so when there is more than one flow in the...
This work is motivated by network applications that require nodes to disseminate their state to others. In particular, vehicular nodes will host applications that periodically disseminate time-critical state across the network to help improve on-road safety. In this work, we want to minimize the average age of state information that a node observes from any other node in networks with hundreds to...
The reliability of traffic flows is a serious challenge to cognitive radio networks due to the interruptions from primary users. A backup path scheme is proposed to protect the secondary user traffic flows against the interruptions from primary users. In such a scheme, the traffic flow can be switched to a backup path if the working path is interrupted by primary users. When primary users leave, the...
Network community needs a flexible platform for network experiment of new architectures, algorithms and protocols in the process of network innovation. However, building such a platform faces lots of challenges due to complicate requirements. In this paper, we present ExpoNet, a platform for rapid concurrent experiment of network innovation on the virtualized programmable infrastructure. ExpoNet integrates...
Among the "store-carry-forward" kind of protocols, the two-hop relay and its variants have become a class of attractive routing protocols for the mobile ad hoc networks (MANETs) due to its efficiency and simplicity. This paper focuses on the performance modeling for two-hop relay with erasure coding, a promising technique for improving the delay performance of conventional two-hop relay...
The use of multiple packet reception (MPR) can alleviate congestion in multi-hop networks and improve network Goodput. However, a sophisticated design is required in order to enable MPR in such networks considering the heterogeneity of transiting packets, both in size and arrival times. In this paper, we introduce a cross-layer MPR-PHY/MAC design suitable for multi-hop ad-hoc networks. Our design...
Access points (APs) of wireless LANs (WLANs), always powered on and ready to serve mobile nodes, consume a large amount of power in total, but are idle during much of the time. Previous protocol-based sleep-wakeup scheduling schemes partially solve this problem, but the large wakeup delay remains a problem. Aiming at realizing Radio-On-Demand WLANs, in this paper, we suggest using an additional wakeup...
In recent years, multimedia network services have moved from a single service to rich services which integrate multiservice capabilities integration. If all service requests require the user to send the request by himself, this will result to a huge control function load and complex service collaboration. In order to address service interaction and reuse the service capability, 3GPP proposes a Service...
In wireless sensor networks, saving energy is crucial in order to increase the network lifetime. Energy is often saved by synchronizing the nodes activity, and having long periods of inactivity, or by having nodes exchange a global activity schedule. The synchronization and the exchange of a global schedule are two examples where information is boadcast from a specific node to the whole network. In...
One critical function of cyber-physical systems (CPS) is object search in the physical world through the cyber sphere that enables interaction between the cyber and physical spheres. Some of the previously proposed physical object search engines use RFID tracking, and others collect the information of object locations into a hierarchical centralized server. The difficulty of widely deploying RFID...
Compressive sensing (CS) provides a new paradigm for efficient data gathering in wireless sensor networks (WSNs). The theory of CS allows to reconstruct all sensor data of the network, while only collecting a small number of measurements at a sink. In this paper, we consider a scenario where a sink collects spatially correlated sensor data from sensor nodes randomly deployed in a region. We investigate...
To synchronize clocks between spacecraft in proximity, the Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol has been proposed. PITS is based on the NTP Interleaved On-Wire Protocol and is capable of being adapted and integrated into CCSDS Proximity-1 Space Link with minimal modifications. In this work, we discuss the correctness and liveness of PITS. Further, we analyze and...
We propose cMAC, a centralized, polling-based protocol for wireless LANs. With cMAC, the access point (AP) sets nodes into the polling mode if they have backlogged data and polls them during the polling period. The AP also periodically opens the contention period to allow nodes with newly arrived data to send data and at the same time announce their queue states. The main feature of cMAC is that it...
Delay tolerant networks (DTNs) characterise a class of emerging networks that suffer from frequent and long-duration partitions. As the storage-carry-forward paradigm is adopted to transfer messages in DTNs, buffer management schemes greatly influence the performance of routing protocols when nodes have limited buffer space. From a network-wide viewpoint, the excessive increase of a single message's...
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