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We propose an immediate re-routing (IRR) extension to RSVP-TE signaling and implement it on our IDBR test-bed. By allowing wavelength conversion during the re-routing process, the proposed scheme can significantly reduce signaling induced blocking.
Secure cooperation incentive schemes usually use public key cryptography, which incur too heavy overhead to be used efficiently in limited-resource nodes. In this paper, we propose a novel incentive scheme that requires public-key operations only for the first packet in a series. The efficient hashing operations are used in the successive packets so that the overhead of the packet series converges...
Wireless multi-hop architectures are increasingly used in many wireless networks. However, it is very difficult to analyse and guarantee end-to-end delay performance over multi-hop wireless paths. In this paper, we develop a cross-layer analytical model to characterise the multi-hop delay performance and derive new mathematical formulae of (DBVP), delay mean and jitter of end-to-end communications...
We present an empirical model of the upstream end-to-end Voice-over-IP (VoIP) delay over a mobile, multi-hop wireless network towards a single gateway. First, we define the “VoIP regime” as the regime of network operation in which a fraction 1 - ϵ of the packets are received by the gateway within the maximum tolerable VoIP networking delay yvoip, and such that e is less than a maximum tolerable outage...
For multi-hop radio networks, traditional flat TDMA access method has the drawback of low wireless resource utility efficiency. To improve the slot reusability, spatial TDMA method can be adopted. In this paper, a new STDMA channel assignment algorithm is proposed which takes the service priority, node position and data status into concerned. In addition to limiting the information stored in and transferred...
Supporting real-time traffic in a wireless network is a challenging task due to the high probability of errors and to the interference that can be provoked by other networks in the same area. There may be situations in which alien traffic is present by default and communication systems have to deal with difficulty by adapting their characteristics to provide the highest possible level of timing guarantees...
In this paper, we propose a channel aware fast utility-based algorithm for allocating power and subcarrier to the users in Orthogonal Frequency Division Multiple Access (OFDMA) networks. Utility function is a proven approach for fair and efficient radio resource allocation. Most of the proposed schemes in the related literature consider continuous rate adaptation. However, our proposed algorithm utilizes...
In DTNs, due to the unique characteristic of frequent partitioning, multicasting is a considerably different and challenging problem. Moreover, the single data multicast is different from multiple data multicast. In this paper, The mathematics model of multiple data multicast for DTNs is established, and the ant colony optimization algorithm introduce to solve the multiple data multicast problem....
Traditional scheduling algorithms are focused in maximizing system throughput considering a grade of fairness. However, maximizing the system throughput does not necessarily result in maximizing the number of satisfied users (users with a packet delay below a threshold). More over, the throughput maximization could cause a low grade of fairness. In this paper, we propose a low complexity scheduling...
In this paper, we study the multi-channel exposed terminal problem in multi-hop wireless networks. We first explain how the multi-channel exposed terminal problem occurs. We then propose a multi-channel MAC protocol, called multi-channel MAC with hopping reservation (MMAC-HR), to resolve the multi-channel exposed terminal problem. The proposed MMAC-HR protocol has the following features: 1) it does...
This paper investigates the performance effects of packet depletion on multihop wireless networks. The resulting capacity usage inefficiencies of link assigned schedules are shown even at the maximum supportable uniform network load. Hybrid node-link assignment is employed to extend transmission rights, allowing nodes to transmit on sets of reserve links when the primary scheduled link experiences...
Cognitive radio (CR) emerges as a key technology to enhance spectrum efficiency and thus creates opportunistic transmissions over links. Supporting the routing function on top of numerous opportunistic links is a must to route packets in a general cognitive radio network (CRN) consisting of multi-radio systems. However, there lacks complete understanding of these highly dynamic available links and...
Traditional contention-based random-access wireless MAC protocols such as IEEE 802.11 DCF are designed for single-hop wireless networks and do not perform well in multi-hop scenarios due to inefficiency in their medium reservation mechanisms. In this paper, we introduce a new MAC protocol, called EMAC, which improves the efficiency of wireless medium reservation for general asynchronous multi-hop...
With the development of novel access technologies e.g. LTE, WiMAX etc., the mobile devices are able to establish services over multiple wireless connections with different momentary capabilities. Being imported from the fixed line communication, the current services deployed are lacking an efficient mechanism of adaptation to the momentary connectivity conditions, which deters the efficiency of the...
Intermittently Connected Wireless Networks (ICWN) or Delay/Disruption Tolerant Networks (DTN), have attracted attention from researchers because of their inherent characteristics, including long latency, low data rate, and intermittent connectivity. Extensive research has been conducted on ICWN, including the architecture, and routing. However, few researchers have investigated the performance of...
Random access is critical to OFDMA wireless networks. However, due to special features of an OFDMA system, how to carry out random access in an efficient manner is still an open issue for OFDMA wireless networks. In this paper, a new random access protocol is proposed for OFDMA wireless networks. It is distinguished by a novel mechanism called concurrent multi-channel carrier sense multiple access...
Existing scheduling schemes for real-time wireless video services generally focus on system throughput or delay, and do not take into account the relationship between the transmission delay and video distortion. In this paper, we develop and evaluate a delay-distortion-aware wireless video scheduling scheme in the framework of cross-layer information adaptation. At first, we construct a general video...
We consider a wireless multi-hop network with sources that are Poisson distributed and relays which are placed on the source-destination line. Given a combined TDMA/ALOHA MAC protocol, we explore the following question of optimal spatial reuse: Increasing the number of nodes that are simultaneously scheduled to transmit in a route allows nodes to transmit more often. At the same time, it results in...
Multi-gigabit per second wireless network devices are emerging for personal area networks (PAN) in the 60 GHz band. Such devices are typically power hungry, largely due to the requisite high speed analog to digital converters (ADCs) that can consume from tens to hundreds of milliwatts of power. This paper studies the use of analog equalization before the ADC to reduce the required ADC resolution....
In cognitive radio networks, the statistical duty cycles (traffic loads) of primary channels have a decisive effect on the throughput and link maintenance of secondary users (SUs). It is very difficult and time-consuming for the SUs to distinguish between primary channels in terms of duty cycles. This paper proposes a multi-user cooperation scheme where SUs share status information about the primary...
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