ACM/IEEE International Conference on Mobile Computing and Networking最新文献

{"title":"An adaptive, high performance mac for long-distance multihop wireless networks","authors":"S. Nedevschi, Rabin K. Patra, S. Surana, S. Ratnasamy, L. Subramanian, E. Brewer","doi":"10.1145/1409944.1409974","DOIUrl":"https://doi.org/10.1145/1409944.1409974","url":null,"abstract":"We consider the problem of efficientMAC design for long-distance WiFi-based mesh networks. In such networks it is common to find long propagation delays, the use of directional antennas, and the presence of inter-link interference. Prior work has shown that these characteristics make traditional CSMA-based MACs a poor choice for long-distance mesh networks and this finding has led to several recent research efforts exploring the use of TDMA-based approaches to media access. In this paper we first identify, and then address, several shortcomings of current TDMA-based proposals. First, because they use fixed-length transmission slots, current TDMA-based solutions do not adapt to dynamic variations in traffic load leading to inefficiencies in both throughput and delay. As we show in this paper, the throughput achieved by existing solutions falls far short of the optimal achievable network throughput. Finally, due to the scheduling constraints imposed by inter-link interference, current TDMA-based solutions only apply to bipartite network topologies.\u0000 In this paper, we present JazzyMac, a simple, practical and efficient MAC protocol that addresses the above limitations. JazzyMac achieves efficiency by allowing variable-length link transmissions slots and then defining a distributed protocol by which nodes adapt the length of their transmission slots to changing traffic demands. JazzyMac is practical in that the adaptation at each node uses purely local information and that our protocol applies to arbitrary network topologies. Finally, the use of dynamic slot sizes allows JazzyMac to achieve better tradeoffs between throughput and delay.\u0000 We evaluate JazzyMac using detailed simulation over a range of traffic patterns and realistic topologies. Our results show that JazzyMac improves throughput in all considered scenarios. This improvement is often substantial (e.g.,in 50% of our scenarios, throughput improves by over 40%) and is particularly pronounced for the common case of asymmetric traffic (e.g.,leading to almost 100% improvements). Furthermore, compared to current solutions, JazzyMac can achieve much better average delay for the same throughput.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125430443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ZipTx: Harnessing Partial Packets in 802.11 Networks","authors":"K. Lin, Nate Kushman, D. Katabi","doi":"10.1145/1409944.1409984","DOIUrl":"https://doi.org/10.1145/1409944.1409984","url":null,"abstract":"Current wireless protocols retransmit any packet that fails the checksum test, even when most of the bits are correctly received. Prior work has recognized this inefficiency, however the proposed solutions (e.g., PPR, HARQ and SOFT) require changes to the hardware and physical layer, and hence are not usable in today's WLANs and mesh networks. They are further tested in channels with fixed modulation and coding, whereas production 802.11 networks adapt their modulation and codes to maximize their ability to correct erroneous bits.\u0000 This paper makes two key contributions: 1) it introduces ZipTx, a software-only solution that harvests the gains from using correct bits in corrupted packets using existing hardware, and 2) it characterizes the true gains of partially correct packets for the entire range of operation of 802.11 networks, and in the presence of adaptive modulation and error correcting codes. We implement ZipTx as a driver extension and evaluate our implementation in both outdoor and indoor environments, showing that ZipTx significantly improves the throughput.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129312602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ditto: a system for opportunistic caching in multi-hop wireless networks","authors":"Fahad R. Dogar, Amar Phanishayee, Himabindu Pucha, Olatunji Ruwase, D. Andersen","doi":"10.1145/1409944.1409977","DOIUrl":"https://doi.org/10.1145/1409944.1409977","url":null,"abstract":"This paper presents the design, implementation, and evaluation of Ditto, a system that opportunistically caches overheard data to improve subsequent transfer throughput in wireless mesh networks. While mesh networks have been proposed as a way to provide cheap, easily deployable Internet access, they must maintain high transfer throughput to be able to compete with other last-mile technologies. Unfortunately, doing so is difficult because multi-hop wireless transmissions interfere with each other, reducing the available capacity on the network. This problem is particularly severe in common gateway-based scenarios in which nearly all transmissions go through one or a few gateways from the mesh network to the Internet.\u0000 Ditto exploits on-path as well as opportunistic caching based on overhearing to improve the throughput of data transfers and to reduce load on the gateways. It uses content-based naming to provide application independent caching at the granularity of small chunks, a feature that is key to being able to cache partially overheard data transfers. Our evaluation of Ditto shows that it can achieve significant performance gains for cached data, increasing throughput by up to 7x over simpler on-path caching schemes, and by up to an order of magnitude over no caching.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121787988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-band spectrum sensing in cognitive radio networks: energy detection or feature detection?","authors":"Hyoil Kim, K. Shin","doi":"10.1145/1409944.1409948","DOIUrl":"https://doi.org/10.1145/1409944.1409948","url":null,"abstract":"In a cognitive radio network (CRN), in-band spectrum sensing is essential for the protection of legacy spectrum users, with which the presence of primary users (PUs) can be detected promptly, allowing secondary users (SUs) to vacate the channels immediately. For in-band sensing, it is important to meet the detectability requirements, such as the maximum allowed latency of detection (e.g., 2 seconds in IEEE 802.22) and the probability of mis-detection and false-alarm. In this paper, we propose an effcient periodic in-band sensing algorithm that optimizes sensing-frequency and sensing-time by minimizing sensing overhead while meeting the detectability requirements. The proposed scheme determines the better of energy or feature detection that incurs less sensing overhead at each SNR level, and derives the threshold aRSSthreshold on the average received signal strength (RSS) of a primary signal below which feature detection is preferred. We showed that energy detection under lognormal shadowing could still perform well at the average SNR < SNRwall [1] when collaborative sensing is used for its location diversity. Two key factors affecting detection performance are also considered: noise uncertainty and inter-CRN interference. aRSSthreshold appears to lie between -114.6 dBm and -109.9 dBm with the noise uncertainty ranging from 0.5 dB to 2 dB, and between -112.9 dBm and -110.5 dBm with 1~6 interfering CRNs.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125134248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wireless device identification with radiometric signatures","authors":"V. Brik, Suman Banerjee, M. Gruteser, Sangho Oh","doi":"10.1145/1409944.1409959","DOIUrl":"https://doi.org/10.1145/1409944.1409959","url":null,"abstract":"We design, implement, and evaluate a technique to identify the source network interface card (NIC) of an IEEE 802.11 frame through passive radio-frequency analysis. This technique, called PARADIS, leverages minute imperfections of transmitter hardware that are acquired at manufacture and are present even in otherwise identical NICs. These imperfections are transmitter-specific and manifest themselves as artifacts of the emitted signals. In PARADIS, we measure differentiating artifacts of individual wireless frames in the modulation domain, apply suitable machine-learning classification tools to achieve significantly higher degrees of NIC identification accuracy than prior best known schemes.\u0000 We experimentally demonstrate effectiveness of PARADIS in differentiating between more than 130 identical 802.11 NICs with accuracy in excess of 99%. Our results also show that the accuracy of PARADIS is resilient against ambient noise and fluctuations of the wireless channel.\u0000 Although our implementation deals exclusively with IEEE 802.11, the approach itself is general and will work with any digital modulation scheme.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123360490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancing wireless link signatures for location distinction","authors":"Junxing Zhang, M. H. Firooz, Neal Patwari, S. Kasera","doi":"10.1145/1409944.1409949","DOIUrl":"https://doi.org/10.1145/1409944.1409949","url":null,"abstract":"Location distinction is the ability to determine when a device has changed its position. We explore the opportunity to use sophisticated PHY-layer measurements in wireless networking systems for location distinction. We first compare two existing location distinction methods - one based on channel gains of multi-tonal probes, and another on channel impulse response. Next, we combine the benefits of these two methods to develop a new link measurement that we call the complex temporal signature. We use a 2.4 GHz link measurement data set, obtained from CRAWDAD [10], to evaluate the three location distinction methods. We find that the complex temporal signature method performs significantly better compared to the existing methods. We also perform new measurements to understand and model the temporal behavior of link signatures over time. We integrate our model in our location distinction mechanism and significantly reduce the probability of false alarms due to temporal variations of link signatures.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126831657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"eBay in the Sky: strategy-proof wireless spectrum auctions","authors":"Xia Zhou, Sorabh Gandhi, S. Suri, Haitao Zheng","doi":"10.1145/1409944.1409947","DOIUrl":"https://doi.org/10.1145/1409944.1409947","url":null,"abstract":"Market-driven dynamic spectrum auctions can drastically improve the spectrum availability for wireless networks struggling to obtain additional spectrum. However, they face significant challenges due to the fear of market manipulation. A truthful or strategy-proof spectrum auction eliminates the fear by enforcing players to bid their true valuations of the spectrum. Hence bidders can avoid the expensive overhead of strategizing over others and the auctioneer can maximize its revenue by assigning spectrum to bidders who value it the most. Conventional truthful designs, however, either fail or become computationally intractable when applied to spectrum auctions. In this paper, we propose VERITAS, a truthful and computationally-efficient spectrum auction to support an eBay-like dynamic spectrum market. VERITAS makes an important contribution of maintaining truthfulness while maximizing spectrum utilization. We show analytically that VERITAS is truthful, efficient, and has a polynomial complexity of O(n3k) when n bidders compete for k spectrum bands. Simulation results show that VERITAS outperforms the extensions of conventional truthful designs by up to 200% in spectrum utilization. Finally, VERITAS supports diverse bidding formats and enables the auctioneer to reconfigure allocations for multiple market objectives.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114670482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experiences in a 3G network: interplay between the wireless channel and applications","authors":"Xin Liu, Ashwin Sridharan, S. Machiraju, Mukund Seshadri, H. Zang","doi":"10.1145/1409944.1409969","DOIUrl":"https://doi.org/10.1145/1409944.1409969","url":null,"abstract":"We present an experimental characterization of the physical and MAC layers in CDMA 1xEV-DO and their impact on transport layer performance. The 1xEV-DO network is currently the fastest mobile broadband cellular network, offering data rates of up to 3.1 Mbps for both stationary and mobile users. These rates are achieved by using novel capacity enhancement techniques at the lower layers. Specifically, 1xEV-DO incorporates rapid channel rate adaptation in response to signal conditions, and opportunistic scheduling to exploit channel fluctuations. Although shown to perform well in isolation, there is no comprehensive literature that examines the impact of these features on transport layer and application performance in real networks.\u0000 We take the first step in addressing this issue through a large set of experiments conducted on a commercial 1xEV-DO network. Our evaluation includes both stationary and mobile scenarios wherein we transferred data using four popular transport protocols: TCPReno, TCP-Vegas, TCP-Westwood, and TCP-Cubic, and logged detailed measurements about wireless channel level characteristics as well as transport layer performance. We analyzed data from several days of experiments and inferred the properties of the physical, MAC and transport layers, as well as potential interactions between them. We find that the wireless channel data rate shows significant variability over long time scales on the order of hours, but retains high memory and predictability over small time scales on the order of milliseconds. We also find that loss-based TCP variants are largely unaffected by channel variations due to the presence of large buffers, and hence able to achieve in excess of 80% of the system capacity.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"34 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126165296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Incentive-compatible opportunistic routing for wireless networks","authors":"Fan Wu, Tingting Chen, S. Zhong, Erran L. Li, Y. Yang","doi":"10.1145/1409944.1409979","DOIUrl":"https://doi.org/10.1145/1409944.1409979","url":null,"abstract":"User-contributed wireless mesh networks are a disruptive technology that may fundamentally change the economics of edge network access and bring the benefits of a computer network infrastructure to local communities at low cost, anywhere in the world. To achieve high throughput despite highly unpredictable and lossy wireless channels, it is essential that such networks take advantage of transmission opportunities wherever they emerge. However, as opportunistic routing departs from the traditional but less effective deterministic, shortest-path based routing, user nodes in such networks may have less incentive to follow protocols and contribute. In this paper, we present the first routing protocols in which it is incentive-compatible for each user node to honestly participate in the routing despite opportunistic transmissions. We not only rigorously prove the properties of our protocols but also thoroughly evaluate a complete implementation of our protocols. Experiments show that there is a 5.8%-58.0% gain in throughput when compared with an opportunistic routing protocol that does not provide incentives and users can act selfishly.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124967692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On link-layer reliability and stability for wireless communication","authors":"S. Soltani, K. Misra, H. Radha","doi":"10.1145/1409944.1409982","DOIUrl":"https://doi.org/10.1145/1409944.1409982","url":null,"abstract":"A primary focus of popular wireless link-layer protocols is to achieve some level of reliability using ARQ or Hybrid ARQ mechanisms. However, these and other leading link-layer protocols largely ignore the stability aspect of wireless communication, and rely on higher layers to provide stable traffic flow control. This design strategy has led to a great deal of inefficiency in throughput and to other major issues (such as the well-known TCP over-wireless performance degradation phenomenon and the numerous studies in attempt to fix it). In this paper, we propose a paradigm shift where both reliability and stability are targeted using an Automatic Code Embedding (ACE) wireless link-layer protocol. To the best of our knowledge this is the first effort to develop a theoretical framework for analyzing and designing a wireless link-layer protocol that targets system stability in conjunction with reliable communication. We present two distinct analytical frameworks to determine optimal code embedding rates which ensure system reliability and stability for wide range of traffic demand. An important conclusion of our analysis is that various traffic demand can be met using a packet-by-packet code embedding rate constraint that is independent of traffic type. We demonstrate experimentally that ACE provides both rapid and reliable point-to-point wireless data transmission for realtime and non-realtime traffic over real channel traces collected on 802.11b WLAN. We also have conducted extensive TCP simulations in conjunction with ACE; and we demonstrate the high level of efficiency and stability that can be achieved for TCP over ACE, while not making any changes to TCP. Further, the implementation of ACE for real-time video communication shows performance gains of 5-10dB over IEEE ARQ schemes. More importantly, ACE is layer oblivious and requires no changes to higher or lower PHY layers.","PeriodicalId":378295,"journal":{"name":"ACM/IEEE International Conference on Mobile Computing and Networking","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125874139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}