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Mobile and Wireless Networking (iCOST), 2011 International Conference on Selected Topics in

Date 10-12 Oct. 2011

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Displaying Results 1 - 25 of 29
  • Index

    Page(s): i
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    Freely Available from IEEE
  • Organization Committee

    Page(s): ii - vii
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  • Technical program in detail

    Page(s): viii - xi
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  • Wireless sensor and actor networks: e-Health, e-Science, e-Decisions

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5233 KB) |  | HTML iconHTML  

    Wireless sensor networks permit to gather information about the world and to act on it at an unprecedentedly detailed level. They are transforming profoundly the way we live as individuals and interact with the society and our environment. In the medical context they can be used at following levels: (1) direct monitoring and supporting the health of a specific patient [e-Health], (2) quality assurance of the applied treatments and devices, verification of medical models [e-Science], (3) taking higher level decisions, either directly or by advising humans (drug approval, combating epidemics) [e-Decisions]. A system that observes and actively influences the humans and their environment is inherently entangled in ethical problems. Even if it is designed and run by noble researchers on behalf of honest leaders, possibly controlled by educated community, it is not neutral. Its every decision should be analyzed from many perspectives, the actors and stakeholders should be identified and their positions understood. Since the relative values of possible actions depend on the actual context, its assessment is of crucial importance. These issues have to be handled explicitly, notably as the ethical principles implemented by such a system may not be universally accepted. This paper presents the issues faced in the design and deployment of a sensor/actor system in a broader context of goals, values and ethical trade-offs. View full abstract»

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  • Implementation analysis of the IEEE 802.15.4 MAC for wireless sensor networks

    Page(s): 7 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (150 KB) |  | HTML iconHTML  

    IEEE 802.15.4 is the dominant Medium Access Control protocol in wireless sensor networks. To implement this protocol on such severely resource constraint devices, several trade-offs have to be considered. This paper presents an analysis of IEEE 802.15.4 software implementations available for typical sensor node systems, such as the MSP430 from Texas Instruments. We discuss the available implementations concerning the supported features, flexibility issues and the efficiency of the implementations. The latter is based on a static code analysis that allows to measure and compare the number of clock cycles, needed to execute specific MAC functionalities. The result of the study is that the performance of the implementations does not correlate with the number of supported features but rather inversely with the implementation flexibility. The results do not only support integrators of 802.15.4-based networks but help identifying key aspects of future implementations of the protocol. View full abstract»

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  • An energy aware MPR-based broadcasting algorithms for wireless sensor networks

    Page(s): 13 - 18
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (883 KB) |  | HTML iconHTML  

    Broadcasting in wireless sensor networks (WSN) is to disseminate packets of data from a node to all nodes in the network. Since wireless communications consume great amounts of sensor's energy, many algorithms and methods were introduced to minimize the cost of broadcasting such as MPR (Multipoint Relay) and DS-MPR (Dominated connecting Set with MPR). In this paper, we introduce first, a slight modification of MPR, by involving the remaining energy of sensors in the selection of relay nodes. We call our algorithm MPR remaining Energy (MPRE). Then, we focus on DS-MPR which also involves the remaining energy of nodes in the selection of relay nodes, so we modify it to become applicable in a realistic environment. We call our second algorithm Realistic environment with DS-MPR÷(RDS-MPR). We illustrate that our algorithm increases the lifetime of nodes, compared to MPR and pure flooding, due to their cooperative way to choose the relay sensors and their balancing of relaying nodes. View full abstract»

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  • Adaptive channel hopping for wireless sensor networks

    Page(s): 19 - 23
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (670 KB) |  | HTML iconHTML  

    Wireless sensor networks (WSN) are an essential element of the Internet of Things. However, their performance is influenced by many factors such as interference from other co-located wireless communication technologies that are sharing the same spectrum and fading due to environmental factors. Channel hopping is one of several adaptation techniques introduced to mitigate these adverse effects. This paper investigates adaptive channel hopping and the advantages and costs related to augmenting existing WSN systems with this capability. We provide complete design and implementation details on OpenWSN considering specifically the case of IEEE 802.15.4e, and also present the results of our experiments. The main finding of this work is that blacklisting can provide a significant improvement in the performance of channel hopping protocols and thus enhance the overall reliability of WSNs in the presence of interference and fading. View full abstract»

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  • IFRP: An Intrusion/Fault tolerant Routing Protocol for increasing resiliency and reliability in wireless sensor networks

    Page(s): 24 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (485 KB) |  | HTML iconHTML  

    With commonness of utilizing wireless sensor networks in sensitive applications like military and civil domains, the necessity for network security and reliability has become a critical concern. In this paper, we proposed IFRP (an Intrusion/Fault tolerant Routing Protocol). IFRP uses both single and multipath to increase reliability and resiliency while considering energy efficiency. Routing has been switch from single path to multipath in the face of malicious behavior by local warden technique. In addition, IFRP detects and isolates intruder or faulty nodes by utilizing of local warden technique and centralized decision. Our simulations show that IFRP can increase reliability and effectiveness against nodes, which dropped packets, with acceptable energy consumption. View full abstract»

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  • A stochastic network calculus approach for the end-to-end delay analysis of LTE networks

    Page(s): 30 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (770 KB) |  | HTML iconHTML  

    The last decade has seen an explosive growth in wireless network services and consequently an increasing demand of high data rates on wireless networks, and the demand of users on real-time traffic is growing. The quality of service (QoS) requirements of different applications are different, for example, the real-time applications are delay-sensitive, yet can tolerant certain data loss. An intrinsic characteristic of radio communication is that the instantaneous radio-channel quality varies in time. Since stochastic network calculus takes the stochastic characteristics of traffic and service processes into consideration to make better use of their statistical multiplexing gains, so we take the 3GPP long term evolution (LTE) as the background, and construct a framework of analyzing the performance of the LTE networks by modeling the arrival model and the service model using stochastic network calculus. Numerical analyses are conducted to prove the effectiveness of the framework. View full abstract»

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  • Performance evaluation of backoff algorithms for medium access in wireless networks

    Page(s): 36 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (579 KB) |  | HTML iconHTML  

    Consider a backoff algorithm for medium access in wireless networks where a node chooses with probability 1-q to transmit right away and with probability q to transmit after CW slots, where CW is the maximum value of the contention window. We study a variation of the 802.11 protocol called XVBEB which uses the above backoff scheme and give a theoretical analysis of its saturation throughput. Simulation results show that the throughput of XVBEB is better than that of 802.11 for saturated CBR traffic. Furthermore, XVBEB also exhibits lower packet loss, delay and delay variation than 802.11 for both VBR and VoIP traffic for a variety of load conditions. View full abstract»

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  • A new channel reservation scheme to reduce call blocking in cellular networks

    Page(s): 42 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (695 KB) |  | HTML iconHTML  

    Cellular operators are facing difficulties in supporting a huge increment in the subscribers due to spectrum and equipment restrictions. There have been many proposals in the area of increasing call carrying capacity such as Reuse Partitioning and Directed Retry. However, such action increases the size of the network and results to higher installation, maintenance and optimization costs for the cellular operator. In this paper we are proposing a cost effective new channel reservation scheme based on subscribers' average call duration which can be implemented in any existing cell. A cell has been considered which has very few allocated channels and is also unable to execute load balancing methods such as channel borrowing, call transfer etc. Also, the average call duration of the subscribers are taken in the range of 0 - 40 minutes. A cell with such restrictions may have higher blocking probability, but the results show that the proposed channel allocation scheme can effectively reduce the overall call-blocking for such cell. This scheme is particularly useful in a cell having heavy traffic with mostly business calls. View full abstract»

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  • Comparison of path loss prediction models and field measurements for cellular networks in Turkey

    Page(s): 48 - 53
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1660 KB) |  | HTML iconHTML  

    Cellular network design for a specific area requires precise knowledge of the propagation characteristics of the radio channel in that area. This paper discusses the applicability of some well known theoretical models to the specific conditions in Izmir, Turkey. Three path loss models were used to predict the path loss in three different frequency bands. Advanced Okumura-Hata, Advanced Walfisch-Ikegami and Algorithm 9999 were used to predict the path loss in certain areas of Izmir, Turkey. The simulation results were compared to real signal strength measurements obtained from live GSM and WCDMA cellular networks and it was concluded that Algorithm 9999 performs best in the dense urban, urban and suburban environments of Izmir. View full abstract»

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  • Low complexity multi-criteria ranking based greedy algorithm for dynamic PRB allocation in 4G systems

    Page(s): 54 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (499 KB) |  | HTML iconHTML  

    A computationally efficient multi-criteria ranking based greedy (MCRG) algorithm is proposed for physical resource block (PRB) allocation in the fourth generation (4G) systems, where the users' utilities are ranked with multiple criteria, to enhance the performance of the basic greedy algorithm. The MCRG algorithm not only outperforms the previous single criterion ranking based greedy algorithm in terms of throughput and outage probability, but also provides a near optimal performance, irrespective of the optimisation utility employed. In particular, when the MCRG algorithm is used to optimise the channel frequency response (CFR) utility, the overall computational complexity is kept at a very low level, without sacrificing the performance. View full abstract»

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  • A low complexity carrier frequency synchronization for OFDMA uplink transmissions

    Page(s): 59 - 63
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (251 KB) |  | HTML iconHTML  

    In this paper, we study the estimation of multiple carrier frequency offsets (CFOs) in a uplink orthogonal frequency division multiple access (OFDMA) system using training sequences. The proposed method can estimate the CFO values of all users in one OFDM block without knowing the channel responses. Unlike most earlier results, the proposed method does not involve any nonlinear search and thus has a much lower complexity. Simulation results show that our proposed method provides a comparable performance with the maximum likelihood (ML) CFO estimator. View full abstract»

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  • Adaptive Fuzzy Spray and Wait: Efficient routing for Opportunistic Networks

    Page(s): 64 - 69
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (904 KB) |  | HTML iconHTML  

    The technological advancement in the area of wireless networking is ultimately envisioned to reach complete and seamless ubiquity, where virtually every point on earth will need to be covered by Internet access. Low connectivity environments have emerged as a major challenge, and accordingly Opportunistic Networks arose as a promising solution. While these networks do not assume the existence of a path from the source to the destination, they opportunistically utilize any available resource to maximize throughput. Routing protocols in such environments have always tried to target an increased delivery probability, a shorter delay, and a reduced overhead. In this work, we try to balance these apparently conflicting goals by introducing “Adaptive Fuzzy Spray and Wait”, an optimized routing scheme for opportunistic networks. On top of the overhead reduction, we argue that the spray-based opportunistic routing techniques can attain higher delivery probability through integrating the adequate buffer prioritization and dropping policies. Towards that purpose, we employ a fuzzy decision making scheme. We also tackle the limitations of the previous approaches by allowing a full-adaptation to the varying network parameters. Extensive simulations using the ONE (Opportunistic Network Environment) simulator [1] show the robustness and effectiveness of the algorithm under challenged network conditions. View full abstract»

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  • ACCOP: Adaptive Cost-Constrained and delay-optimized data allocation over parallel opportunistic networks

    Page(s): 70 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (856 KB) |  | HTML iconHTML  

    As wireless and mobile technologies are becoming increasingly pervasive, an uninterrupted connectivity in mobile devices is becoming a necessity rather than a luxury. When dealing with challenged networking environments, this necessity becomes harder to achieve in the absence of end-to-end paths from servers to mobiles. One of the main techniques employed to such conditions is to simultaneously use parallel available networks. In this work, we tackle the problem of data allocation to parallel networks in challenged environments, targeting a minimized delay while abiding by user preset budget. We propose ACCOP, an Adaptive, Cost-Constrained, and delay-OPtimized data-to-channel allocation scheme that efficiently exploits parallel channels typically accessible from the mobile devices. Our technique replaces the traditional, inefficient, and brute-force schemes through employing Lagrange multipliers to minimize the delivery delay. Furthermore, we show how ACCOP can dynamically adjust to the changing network conditions. Through analytical and experimental tools, we demonstrate that our system achieves faster delivery and higher performance while remaining computationally inexpensive. View full abstract»

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  • A novel congestion control scheme for delay tolerant networks

    Page(s): 76 - 81
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (245 KB) |  | HTML iconHTML  

    Due to limited storage capacity in the DTN nodes, storage congestion occurs when too many bundles are contending for this scarce resource. As a result, bundle loss increases and the delivery ratio of the network suffers. In a proactive scheme, a node can decide whether to accept or reject the custody of a new bundle based on its current storage status. In this paper, we propose a novel proactive congestion control scheme for DTN. Our scheme ranks the incoming bundles using their priority and TTL. When congestion occurs, a node accepts or rejects the bundles based on their ranks. We also use the concept of head of line blocking, confidence level, and dropping probability of the bundles to facilitate better decision making. Simulation results show that our scheme achieves 20% to 25% higher delivery ratio than that of the existing schemes. View full abstract»

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  • Impact of social structure on forwarding algorithms in opportunistic networks

    Page(s): 82 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB) |  | HTML iconHTML  

    Opportunistic networks are formed among mobile wireless devices based on spontaneous connectivity such as mobile phone networks using short range radio. Different setting of social structure in such networks gives significant impact on the feasibility and performance. In this paper we aim at understanding how social structure affects forwarding algorithm in various opportunistic network configurations. Having human mobility traces from the real world, we focus on the social structure in terms of centrality and community. We exploit different community detection and centrality calculation from the trace to present the features of such networks. We study a collection of Social-based Forwarding algorithms, such as LABEL, RANK, and BUBBLE [10]. Furthermore, we implement those forwarding algorithms over a Xen-based Haggle testbed [9]. We investigate the impact of community structure and centrality on performance and demonstrate that social structure influences the performance of the social-based Forwarding algorithms. Our result demonstrates that it is important to find appropriate centrality and communities for social networks with complex structure in the design of the social-based data dissemination algorithms. View full abstract»

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  • The availability of fast-flux service networks

    Page(s): 89 - 93
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    Fast-flux service network (FFSN) is consisted of a large scale of computers which have two main functions. Firstly, by providing a pool of huge number of IP addresses, the controller of FFSN can choose the IPs to provide services for their own domain name. Secondly, these computers can be served as agents to hide mother-ship. The character of FFSN is that the DNS records of domain name changes constantly at a high frequency. In this paper, we analyze the issue on the reliability of FFSN. The issue is resulted from the uncontrollable nodes of FFSN. We establish a model to describe the reliability by the theory of Poisson Process, and analyze the relationship between the reliability of FFSN and its size. View full abstract»

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  • A distributed scheduling algorithm for mobile WiMAX networks

    Page(s): 94 - 99
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB) |  | HTML iconHTML  

    In this paper, we propose a scheduling algorithm for mobile WiMAX networks that distributes dynamically the bandwidth among service flows while giving real-time packets more chances to satisfy their QoS requirements. The scheduling in the proposed algorithm is assisted by the subscriber stations, hence requiring two-schedulers, a scheduler at the BS and another one at the SS, where preemption is applied to both of them. At the SS, a preemptive queue being serviced can be preempted if a packet which cannot be delivered within its deadline arrives to a non-preemptive queue. However, at the BS, preemption is only feasible if a critical packet arrives to a non-preemptive downlink queue. The proposed algorithm was integrated with the network simulator NS2 using the MAC layer of the NDSL WiMAX module, then compared its performance to other peer algorithms found in the literature. Simulation results have shown that the proposed approach enhances the throughput and the average delay of real-time QoS classes. View full abstract»

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  • UDP packet data transmission over TETRA radio system

    Page(s): 100 - 103
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    This paper studies the performance of transmitting User Datagram Protocol (UDP) packets over Terrestrial Trunked Radio (TETRA) networks. The IPERF program was used at the client station to generate UDP packets and at the server station to receive these packets and analyze them. Almost 1,800 measurements were taken for different packet sizes. The measurements were made for UDP packet size of 50 bytes to 800 bytes with 50 bytes increment. Additional measurements were done for UDP packet size ranging from 350 bytes to 400 bytes with an increment of 5 bytes. The measurement results were used to draw and relate the data transfer, throughput, jitter and lost packet with reference to the UDP packet size. View full abstract»

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  • An optimized message aggregation method to resolve funneling effect in mobility management

    Page(s): 104 - 109
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (515 KB) |  | HTML iconHTML  

    In infrastructure-based mobile ad hoc networks, every mobile node has to send registration message periodically to register with an Internet Gateway (IG) or update its presence. Since registration messages are delivered to an IG, the mobile nodes near an IG can be congested, thus experiencing a lot of collisions in message transmission. This phenomenon is called “funneling effect.” In this paper, we employ message aggregation technique to resolve the funneling effect and use a skewed time synchronization to maximize the message aggregation. We show by resorting to simulation that the message aggregation technique can alleviate the funneling effect greatly. View full abstract»

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  • Measurement based radio environment database using spectrum sensing in cognitive radio

    Page(s): 110 - 115
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    This paper presents a novel approach for radio environment database (RDB) techniques based on measurement to enable spectrum sharing in cognitive radio. The proposed database in this paper is used to estimate the received signal power of a primary user (PU) at a certain location by secondary users (SU). The received signal power is measured by the measurement nodes such as vehicles at different locations and is mapped in the database together with the information regarding the number of observations. Considering the Rayleigh fading characteristics in the stored data, we investigate the required margin for proper protection of the PU from the interference created by a SU. Through simulations, we show the relationship between the required number of observations at a certain location and the performance attained by the SU while also protecting the rights of the primary systems. View full abstract»

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  • Power-minimizing and rate-maximizing transceivers with integer bit allocation: A duality

    Page(s): 116 - 120
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    In this paper, we consider the bit rate maximizing problem and power minimizing problem with integer bit allocation. We will derive the duality between these two problems. We will show that if a transceiver is optimal for the power-minimizing problem, it is also optimal for the rate maximizing problem, and the converse is true. For the power minimization problem with integer bit allocation, the solution has been found in the literature. However, there is no solution yet for the rate maximization problem with integer bit allocation. The duality allows us to develop an algorithm for finding the rate-maximizing transceiver with integer bit allocation using the solution of power-minimizing system. In the simulations, we will compute the optimal solution for the rate-maximizing problem using the proposed algorithm. View full abstract»

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  • Localization of Wi-Fi Access Point using smartphone's GPS information

    Page(s): 121 - 126
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    Precise localization of Wi-Fi Access Point (AP) is becoming increasingly important with the rise of diverse location-based services based on smartphone. In this article, we propose a new method for precise Wi-Fi AP localization using GPS information of smartphone. The idea is that the possible area of Wi-Fi AP location, called AP_Area, is first determined by measuring GPS information and the Received Signal Strength (RSS) of smartphones from Wi-Fi AP. As the number of measurement points from users' smartphones increases, the AP_Area can be successively narrowed down to the actual AP location. Simulation results show that the proposed algorithm can detect the Wi-Fi AP localization within 5 m (probability over than 80%). View full abstract»

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