waashk/dblp huggingface dataset:
battle management language (bml) as an enabler. according to its definition, a battle management language (bml) is an unambiguous language used to command and control forces and equipment conducting military operations and to provide for situational awareness and a shared, common operational picture. in this paper, we will argue that the use of a bml enables military units to utilize state-of-the-art it techniques for today's operations. in particular, we will discuss the benefits of using bml for military communications in multinational endeavors, for the use of simulation systems in staff training, for decision support, and for automatic information fusion.
maximum a posteriori bit-unstuffing. bit-stuffing is the procedure of introducing an extra bit in the transmitted stream after a fixed number of consecutive ones or zeros. this paper demonstrates that, for conventional unstuffing, the ber experienced by individual bits within a stuffed frame dramatically and monotonically degrades with its positional-index. we also show that when knowledge of the number of stuffed bits is applied to maximum a posteriori (map) bit-unstuffing (mapbu) (through a bcjr algorithm), this trend is significantly mitigated.
experimental triple-play service delivery using commodity wireless lan hardware. in this paper we study the feasibility of utilizing wireless local area network (wlan) technology to deliver the triple-play services (video, voice and data) over a specific system model. existing protocols are shown to not efficiently manage the wireless channel therefore we propose a new triple-play time division multiple access (tp-tdma) media access control (mac) protocol to provide quality of service (qos) for these triple-play services in a point-to-multipoint network over an existing 802.11a physical layer. through extensive simulation analysis, the protocol is shown to offer better performance than the 802.11e enhanced distributed coordination function (edcf). moreover, this protocol is implemented in hardware using the madwifi driver to verify the real-world performance. both results of the simulation study and hardware implementation are provided.
on channel estimation for ofdm based two-way relay networks. we consider the channel estimation issues for two-way relay network (twrn) that employs orthogonal frequency division multiplexing (ofdm) modulation. we propose a two-phase training protocol for channel estimation, which is compatible with two-phase data transmission scheme associated with twrn. it will be seen that channel estimation in twrn is quite different from that in the traditional point-to-point system or even that in the one-way relay network (owrn). the identifiability issue of the channel estimation, which particularly exists for twrn, is studied. simulation results corroborate the effectiveness of the proposed method.
approximated matching-based spectrum access algorithm for heterogenous cognitive networks. we present a novel spectrum access scheme for open spectrum networks. different from existing works, this work considers the scenario that contending secondary users have heterogeneous channel availability. it is proved to be np hard to find the optimal spectrum assignment in this scenario. to solve this problem, a novel approximation algorithm is proposed which is based on the maximum weighted matching technique. the performance of the algorithm is evaluated through extensive simulations. compared with the general optimal spectrum allocation scheme without considering the difference of spectrum availability, the experiments' results demonstrate that the new matching based algorithm improves the network throughput significantly, generally by 20% to 60%. the algorithm's computation complexity is also at a low level of o(m*n2*m).
using limited feedback in power allocation design for a two-hop relay ofdm system. in this paper, we study power allocation (pa) in a single-relay ofdm system with limited feedback. we propose a pa scheme that uses a codebook of quantized pa vectors designed offline and known to the source, relay, and destination. the destination, which has full knowledge of channel side information (csi), chooses one of the codebook vectors and conveys back to the source and relay. with the limited amount of available feedback, the design of an appropriate codebook is central to pa, which varies depending on the destination's strategy to choose the optimal pa vector. assuming high received snr on either link in the relay path, we first derive the optimal pa solutions as the function of channel realizations with two design criteria, maximizing capacity and minimizing error rate. it is found that when there is high received snr in either the relay path or the direct path, the optimal solutions for both criteria reduce to simple forms. for maximizing capacity, the available power should be equally allocated to each ofdm subcarrier shared by the source and relay; while for minimum error rate, the available power should be allocated such that the received snrs for all subcarriers at the destination are the same. the findings lead us to the sub-optimal solutions with great complexity reduction. we then present an adaptation of lloyd's algorithm to construct a codebook to quantize the optimal pa vectors subject to the amount of feedback. simulations show that a mild to negligible performance loss can be achieved with only a few bits of feedback at different snr values.
towards a denial-of-service resilient design of complex ipsec overlays. by monitoring the exchanged ipsec traffic an adversary can usually easily discover the layout of virtual private networks (vpns). of even worse extend is the disclosure if compromised ipsec gateways are considered, for example in remote environments. this revelation enables attackers to identify vital components and may allow him to compromise the availability of the overall infrastructure by launching well-targeted denial-of-service (dos) attacks against them. in this article we present a formal model to analyze the resilience of vpn infrastructures against dos attacks, to estimate the impact of compromised gateways, and to formalize the planning process of more resilient infrastructures.
recipient maximization routing scheme for multicast over ieee 802.16j relay networks. in this paper, we consider the resource allocation problem for multicast over ieee 802.16j wimax networks, which use relay stations to transmit data between the base station and subscriber stations to improve the transmission quality. our objective is to maximize the total number of recipients by allocating resource among the base station and relay stations subject to the resource budget and the channel quality. we prove that the problem is np-hard, and design a polynomial-time algorithm to solve it. the algorithm can be integrated with the multicast mechanism defined in the wimax standards, and can also be applied to any kind of wireless networks that support adaptive modulation and coding schemes. the performance of the algorithm is evaluated through simulations. we show that the typical routing approach is inefficient, whereas our scheme can always utilize relay stations to achieve a superior performance under different channel qualities and resource budgets.
a stochastic mimo model for far-end crosstalk in vdsl cable binders. future digital subscriber line (dsl) systems are supposed to achieve higher data rates by using interference cancellation techniques. since far-end crosstalk (fext) is the major impairment in dsl systems based on frequency division duplexing, mitigation of this interference can increase the signal-to- interference-and-noise ratio, and therefore significantly boost the data rate. for simulation and evaluation of fext cancellation algorithms, more accurate modelling of the multiple-input-multiple-output (mimo) crosstalk channels is needed. until now, dsl standards usually rely on the 99% worst case modelling of crosstalk power-sum for the lines in a binder. this paper proposes a parametric stochastic fext model based on the sum-of-sinusoids approach for the pair-to-pair crosstalk among multiple lines in a binder, which shows a more realistic behaviour than the worst case models.
spectrum sensing using hidden markov modeling. cognitive radio technologies are being developed which allow heterogeneous systems to share spectrum access while minimizing interference to improve the overall efficiency of spectrum usage. interference minimization requires cognitive radio receivers to be able to detect the presence of all other systems competing for spectrum usage, a process often termed "spectrum sensing". this paper focuses on the kernel function of spectrum sensing: blind interference detection from a single, strictly time-limited, received data vector. recent research has identified shortcomings in the operation of classical blind interference detection techniques such as energy detection and radiometry. this paper demonstrates that implicit interference characteristics can be exploited in a formal framework using hidden markov modeling to produce a spectrum sensor with a receiver operating characteristic which is improved on that of energy detection and several other previously reported methods.
latency and capacity optimal broadcasting in wireless multihop networks. in this paper, we study the fundamental properties of broadcasting in multi-hop wireless networks. previous studies have shown that, as long as broadcast capacity is concerned, asymptotically optimal broadcasting is possible in wireless multi-hop networks under very general conditions. however, none of the existing work on broadcast capacity has considered latency in message delivery, which is simply assumed to be finite (but not explicitly bounded). in this paper, we address the issue of investigating the fundamental properties of broadcast communications for what concerns both capacity and latency using a realistic, sinr-based interference model. in particular, we introduce a novel topological notion of network connectivity, and show that, if the network satisfies this property, asymptotically optimal broadcast capacity and latency can be achieved simultaneously. this is in sharp contrast to similar results obtained for the case of unicast transmissions, where strictly bounded latency in message delivery can be achieved only at the expense of asymptotically reducing network capacity. thus, the results presented in this paper show that scalable broadcasting in multi-hop wireless networks is, in principle, possible.
crbs for uwb multipath channel estimation: impact of the overlapping between the mpcs on mpc gain and toa estimation. in this paper we study the impact of the overlapping between neighboring mpcs (multipath component) on the performance of channel estimation. we consider ir-uwb (impulse radio) signals, and the ieee802.15.3a and ieee802.15.4a uwb channel models. we show that for a pulse width (pw) sufficiently smaller than the average mpc rate of arrival (roa) the probability to have more than three overlapping mpcs is relatively small. we derive the crbs (cramer rao bound) for the joint estimation of the mpc gain and toa (time of arrival) in the case of up to three overlapping mpcs. we compute also the average crbs. we show that the crbs obtained by averaging more than 80% of possible cases of the channel, are very close to the bounds obtained under the non-overlapping assumption (nola).
monitoring abnormal traffic flows based on independent component analysis. the randomness of the network behaviors poses serious challenges for discovering the abnormal patterns in network traffic flows. this paper presents a method based on blind source separation approach for detecting abnormal traffic flows. it decomposes the network traffic into two components: the routine pattern and the abnormal pattern. the scale-space filter with adaptive scale is applied to filter the noise without affecting the main behavior patterns which can be used to form the abnormal traffic metrics and profiles. the zero-crossing method is applied to extract the stochastic behavior pulse widths and the largest width is selected as the scale space factor. in this way, the influence of the inherent randomness could be removed or greatly reduced. the extracted patterns of the routine behaviors imply the user's habit and the abnormal patterns are useful for discovering anomalous behaviors such as scanning, flooding and content distribution attacks. a salient feature of the method is that no supervised learning process is needed. this is a very important advantage since obtaining labeled samples in traffic monitoring is extremely difficult. experimental results based on the datasets of an actual network show that this method is effective for monitoring anomaly traffic flows in the gigabytes traffic environment and the identification accuracy is above 95%.
variable-width channel allocation in wireless lan: a game-theoretic perspective. the fixed channelization structure used by ieee 802.11-based wlans constrains the total capacity and leads to unfairness. the concept of variable-width channels is recently proposed to overcome these drawbacks. to investigate the problem of the non-overlapping variable-width channel allocation for selfish access points (aps) in a wlan, we model it as a non-cooperative game. we aim to investigate two fundamental issues on it in this paper: 1) are there some fair and system-optimal nash equilibrium (ne) allocations? 2) how to achieve one of these desirable allocations if they exist? at first, the existence of fair and system-optimal nash equilibria in this game is proved. then, a simple protocol to achieve one of these desirable ne allocations is proposed. considering the implementation issues, a punishment-based method and a transfer-based self-enforcing truth-telling method are proposed for single-stage and multi-stage game scenarios respectively. the numerical results show the effectiveness of our approaches.
underground wireless communication using magnetic induction. underground is a challenging environment for wireless communication since the propagation medium is no longer air but soil, rock and water. the well established wireless communication techniques using electromagnetic (em) waves do not work well in this environment due to three problems: high path loss, dynamic channel condition and large antenna size. new techniques using magnetic induction (mi) can solve two of the three problems (dynamic channel condition and large antenna size), but may still cause even higher path loss. in this paper, a complete characterization of the underground mi communication channel is provided. based on the channel model, the mi waveguide technique for communication is developed in order to reduce the mi path loss. the performance of the traditional em wave systems, the current mi systems and our improved mi waveguide system are quantitatively compared. the results reveal that our mi waveguide system has much lower path loss than the other two cases for any channel conditions.
sampler: an optimal mac algorithm for wireless instrumentation systems. wireless devices provide flexible solutions for industrial instrumentation applications, such as quality control of manufacture of jet engines. in this context, the dominant issues are providing high-throughput, and reliability in the sense of not losing samples due to buffer overflow at the wireless devices. a random medium access control (mac) scheme, such as the ieee 802.15.4, is unlikely to perform well along those metrics. csma/ca, the foundation of ieee 802.15.4, is inefficient at the high-throughput regime. the polling mode of ieee 802.15.4, on the other hand, ignores the buffer constraints, thereby increasing the risk of buffer overflow. in this paper, we propose sampler, a scheduled mac protocol that is optimal, in the sense of minimizing sample losses while maximizing throughput, in the typical scenario where a sophisticated access point forms a star topology with the wireless sensors. we describe sampler, its properties and demonstrate its superior performance compared to random-access mac through simulations.
end-to-end qos provisioning for real-time video streaming over sp-driven p2p networks using admission control. enabling end-to-end quality of service (qos) for real-time video content delivery across heterogeneous p2p networks is challenging but vital for the efficient service provision. in this paper, we present a p2p based admission control mechanism for real-time video streaming driven by service provider (sp). sp-driven p2p network is a network where service provider has a comprehensive control over contracted resource utilization. sp assures the coordination and the creation of overlay p2p network and it is responsible for admission control and resource allocation among others. our proposed qos provision mechanism employs video traffic descriptor (i.e. traffic specification) for performing admission control. before accepting a particular p2p video streaming session, the sp controls the access to the network resources by performing policy and admission control. after retrieving the service availability from its traffic repository, sp decides whether to accept or to reject the request. the proposed sp-driven p2p admission control mechanism is evaluated using ns2 simulator and the results show that our proposed mechanism allows the provisioning of end-to-end qos for delivered video content over p2p network.
a study of network throughput gain in optical-wireless (fiwi) networks subject to peer-to-peer communications. optical-wireless (fiwi) access network is a newly emerged access network architecture which integrates passive optical networks (pons) with wireless mesh networks (wmns) to provide the ubiquitous, low cost, high bandwidth last mile internet access. though the pon subnetwork of fiwi network can provide high bandwidth, the interference in the wireless subnetwork still limits the throughput of fiwi network if all traffic goes online to the internet. however, when peer-to-peer communication from one wireless client to another wireless client is introduced, the proposed integration of pons and wmns can significantly improve the network throughput. in traditional wmns, peer-to-peer communication from one wireless client to another wireless client is carried in the wireless network, which is subject to interferences in wireless communications. in fiwi network, peer-to-peer communication can be carried through the wireless-optical-wireless mode in which the traffic is sent from the source wireless client to its nearest onu, which is then sent to the onu close to the destination wireless client through the pon subnetwork and then delivered to the destination wireless client. such wireless-optical-wireless communication mode introduced by fiwi networks can sustain the interference in wireless subnetwork, thus improving the network throughput. this paper aims to study the network throughput gain in fiwi network subject to peer-to-peer communications and parameters which can affect the network throughput gain. we first have a fair modeling of fiwi networks and traditional wmns. we then present an lp based routing algorithm for fiwi networks. extensive simulations have been carried to study the network throughput gain in fiwi networks subject to peer-to-peer communications compared with traditional wmns. the work provides insightful observations for fully utilizing advantages brought by the integration of pons and wmns in fiwi networks.
an efficient mac layer handoff scheme for wifi-based multichannel wireless mesh networks. compared to traditional wireless networks, wireless mesh networks (wmns) are more efficient in terms of deployment, configuration, and maintenance. however, connecting all routers through wireless connection in wmns results in remarkably lower bandwidth of the network backbone. multichannel technology, where non-interfering channels are used to enable mesh routers to send and receive packets simultaneously, has been extensively adopted to improve the throughput of wmns, and providing seamless roaming in multichannel wmns has become an important topic in wmn research. in this paper, a novel mac layer handoff scheme is proposed as a means of minimizing handoff latency in wifi-based multichannel wmns for seamless communication in real-time applications. by designing a dynamic grouping algorithm for channel selection and allowing mesh routers to switch channels for probe message reply, this new scheme can shorten the waiting time for the detection of available access routers, decrease loss ratio of data packets during handoff, and consequently achieve smooth handoff in the mac layer.
multihomed sip-based network mobility using ieee 802.21 media independent handover. when a group of users or devices move together, network mobility resolves how to manage the location transition of the whole members. two kinds of solutions have been proposed at different layers. network mobility (nemo) basic support protocol (bsp) is the extension of mobile ipv6 at the network layer. on the other hand, session initiation protocol (sip) based network mobility (sip-nemo) is defined at the application layer. however, on the perspective of ubiquitous network environment, a mobile router requires to possess several egress paths to the internet for providing uninterrupted services and aggregating good enough bandwidth. multihoming in network mobility support becomes one urgent and nessceary issue. since mobile ipv6 based nemo bsp, called mipv6-nemo hereafter for convenience, uses a bi-directional tunnel between home agent and mobile router, multihomed mipv6-nemo would suffer and deepen header overhead and suboptimal routing. in the past, we have proposed sip-nemo to achieve route optimization. in this paper, we investigate and analyze how to extend the current sip-nemo to support multihoming further. the proposed multihomed sipnemo is simulated in different cases and integrated with the ieee 802.21 media independent handover (mih) standard. according to the simulation result, the sip-nemo can keep route optimization no matter which multihomed case is configured.
blind spectrum sensing for cognitive radio based on signal space dimension estimation. based on information theoretic tools, a new spectrum sensing method is proposed in this paper to detect vacant sub-bands in the radio spectrum1. specifically, based on the subspace analysis of the received signal, we present a new method to detect the signal presence in a blind way. we have shown that the analysis of signal dimension can assist blind spectrum sensing procedure. indeed, we have shown that the slope change, from positive to negative trend, of the signal space dimension curve is representative of the transition from a vacant band to an occupied band (and vice versa). in fact, the number of significant eigenvalues is determined by the value that minimizes the akaike's information criterion (aic) and is directly related to the presence/absance of data in the signal. the validation of this new method is based on experimental measurements captured by eurécom rf agile platform operating from 200 mhz to 7.5 ghz. simulations show good results in terms of spectrum holes detection.