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Wireless, Mobile and Sensor Networks, 2007. (CCWMSN07). IET Conference on

Date 12-14 Dec. 2007

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Displaying Results 1 - 25 of 271
  • A model studying for the IEEE 802.11 DCF

    Publication Year: 2007 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (713 KB)  

    The most mature medium access control protocol for wireless local area networks is the IEEE 802.11 standard. The primary access mode of this protocol is based on the mechanism of carrier sense multiple access with binary exponential backoff. We develop a finite-source feedback queueing model for this access mode. In this model, we derive expressions for the throughput and the first moment of the delay and a set of equations to compute the Laplace Stieltjes Transform and higher moments of the delay. The accuracy of the model is verified by simulation. View full abstract»

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  • A method of multi-user detection based on Independent Component Analysis for DS-CDMA systems

    Publication Year: 2007 , Page(s): 5 - 7
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (663 KB)  

    The DS-CDMA signal model and the noisy linear independent component analysis (ICA) model are analyzed in this paper. Comparing these models shows that they have the same form. The adaptive minimum mean-square error (MMSE) multiuse detection based on ICA is proposed. It uses the output of adaptive MMSE multi-user detection to initialize the ICA iterations, not only the known spread information of interesting user is used to overcome the uncertainness of ICA, but also the character of statistical independence is used. The simulation results show that the performance is improved obviously. View full abstract»

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  • A novel feed-forward neural network blind multi-user detection algorithm by augmented Lagrange optimization

    Publication Year: 2007 , Page(s): 8 - 11
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (589 KB)  

    A feed-forward neural network blind multi-user detection algorithm was proposed. Feed-forward neural network and constant modulus algorithm (CMA) were consociated to complete blind multi-user detection. A constant modulus cost function firstly was constructed and the cost function with restrict condition was optimized by augmented Lagrange method. Blind multi-user detection algorithm was realized by iterative equations of FNN. And computer simulation indicates the new algorithm improves the ability to overcome MAI and makes bit error ratio lower. View full abstract»

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  • On the second-order statistics of a new fading model for land mobile satellite channels

    Publication Year: 2007 , Page(s): 12 - 15
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (793 KB)  

    In this paper, the second-order statistics of a new stochastic model for land mobile satellite channels are studied. From the proposed analytical model, a deterministic computer simulation model is derived by replacing the coloured Gaussian noise processes by finite sums of weighted sinusoids. Closed expressions of the level crossing rate and average duration of fades are derived for the analytical model. Since the Rayleigh fading channel is a special case of our proposed model, the derived expression can be verified by comparison with results for the Rayleigh fading channel. A numerical optimization procedure has been also taken in order to fit the statistics of our proposed analytical model to an equivalent real-world land mobile satellite channel for light and heavy shadowing environments. Various theoretical and simulation results show that both the analytical and computer simulation models have an excellent performance. View full abstract»

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  • A novel compact dual-frequency PIFA for WLAN applications

    Publication Year: 2007 , Page(s): 16 - 19
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1414 KB)  

    A novel compact dual-frequency planar inverted-F antenna for Bluetooth and WLAN applications is presented. The antenna owns the feature of compact operation and can be easily placed in the display panel of the laptop computer. The F-shaped slot and ladder notches configuration is employed to satisfy the technical requirements of the WLAN antennas. The antenna achieves an impedance bandwidth of 400 MHz (2.21~2.61 GHz) in Bluetooth band and 1070 MHz (4.95~6.02 GHz) in WLAN band. The gain of the antenna changes from 3.1 dBi to 6.7 dBi. View full abstract»

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  • Performance research and simulations on improvement adaptive iterative decoder algorithms of Turbo codes

    Publication Year: 2007 , Page(s): 20 - 23
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1173 KB)  

    Turbo codes were proposed in 1993 and lots of work was done on this aspect .But decoding algorithms for Turbo codes were complex, and had large iteration delay. Several adaptive iterative decoding algorithms for Turbo codes were proposed to reduce decoding delay. In this paper, we investigate and improve these adaptive algorithms. According to the improvement adaptive iterative decoder algorithm, the average number for turbo decoding was decreased, while the BER performance obtained was not degraded. View full abstract»

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  • Uplink resource allocation in OFDMA relay-assisted cellular network with fairness

    Publication Year: 2007 , Page(s): 24 - 27
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1662 KB)  

    Uplink subcarrier and power allocation is studied for OFDMA relay-assisted cellular network. Assuming that the base station has all the channel state information (CSI), an optimization problem for an adaptive subcarrier and power allocation scheme that maximizes system capacity while guaranteeing minimum resources for each user with constraint of overall transmission power is formulated. Since the optimal solution is computationally complex to obtain, a two-step suboptimal approach is proposed. The subcarrier allocation in the first step based on the equivalent channel- noise-ratio can exploit multiuser diversity as much as possible while impose certain fairness among users. In the second step power distribution methods with spacail water-filling and MS-based water-filling are proposed to maximize capacity of predetermined subcarrier assignment. Numerical results show that the proposed solution can achieve significant improvement on system capacity while guarantee minimum fairness among users. View full abstract»

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  • Enhanced parallel-interference cancellation receiver based on MIMO systems

    Publication Year: 2007 , Page(s): 28 - 31
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1218 KB)  

    VBLAST receiver is effective technique in achieving high data rate in MIMO wireless communications. However, the complexity of VBLAST is very high because much time must be consume in performing linear nulling, successive interference cancelling and sorting, and the application of VBLAST is limited. The performance of parallel interference cancellation (PIC) receiver isn't good as VBLAST though its signal processing time delay is smaller than VBLAST. In this paper, an enhanced PIC receiver is proposed. The first stage is using QR detection and the initial symbol estimation vector may be obtained. The second stage is applied the successive PIC scheme. After one layer is detected, the layer's data in the initial vector is updated by the new detected layer data. The simulation results indicate that the performance of the propose receiver outperforms VBLAST receiver, at error bit rate 10-3, the proposed scheme may obtain 1dB gains compared to VBLAST. View full abstract»

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  • Design for the reader of UHF Radio frequency identification

    Publication Year: 2007 , Page(s): 32 - 35
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1254 KB)  

    Ultra high frequency radio frequency identification (UHF RFID) system is becoming more wide spread due to its advantages, such as fast read-write speed, large memory, long recognition distance and the capacity of simultaneously reading/writing multi-tags. In this paper, we introduce the characteristics, structure, principle and read/write method of a UHF RFID reader, and present the solution of its interrogator and flow of DSP software program. Received backscatter modulation waves are directly demodulated to basedband signals using zero IF technology. The reader is designed as a quadrature (I/Q) one, which can avoid null points of received signals and enhance the demodulation sensitivity. View full abstract»

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  • RFID Coding, Name and Information Service for Internet of Things

    Publication Year: 2007 , Page(s): 36 - 39
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1961 KB)  

    Based on the technology of Internet of Things, its working processes is described in detail: RFID (radio frequency identification) coding, RFID-NS (RFID-name service) and RFID-IS (RFID-information service). By taking EPC code as a significant example, firstly, the conversion between bar code and RFID code is analyzed; secondly, the transformation principle from RFID code to domain name by RFID-NS is discussed; finally, the structure of RFID-IS is given, providing reference for the building and study for Internet of Things in China. View full abstract»

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  • Design and implementation of an improved Mobile IPv6 protocol

    Publication Year: 2007 , Page(s): 40 - 43
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1241 KB)  

    According to the standard mobile IPv6 proposed by IETF, a mobile node must update its home agent and correspondent nodes whenever it moves to a new position in foreign networks. This must result in the high binding and sending cost, as well as the degradation of network performance. In this paper, an improved mobile IPv6 protocol is presented, which can reduce the binding cost by dividing binding update of the mobile nodes into the home update and the local update, and therefore improve the performance of the network. View full abstract»

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  • Bluetooth Access Point Mobility Representative Middleware

    Publication Year: 2007 , Page(s): 44 - 47
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2001 KB)  

    The wireless Internet has become ubiquitous and there has been tremendous quantity of Bluetooth data terminal need Internet access. For the coverage and capacity reason, a cellular architecture is usually used for Bluetooth access point in hot spot area. This architecture in Bluetooth access network induces high rate of handoff and service discontinuity. The paper proposes Bluetooth mobility representative middleware solution, which performs effective low-level handoff management to transparently avoid service interruptions during handoffs. The mobility representative has the immediate visibility of available local Bluetooth resource and user micro-mobility. It can simplify the high capacity Bluetooth access point system design. View full abstract»

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  • EDiCa: A enhanced distributed anticollison algorithm for mobile RFID reader network

    Publication Year: 2007 , Page(s): 48 - 51
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (186 KB)  

    With RFID technology rapidly development, there are many key technologies that have to research. The reader collision problem (RCP) is one of which EDiCa (enhanced distributed tag access with collision-avoidance among mobile RFID readers) is a distributed anticollision algorithm for mobile RFID reader and which is based on before RFID reader anticollison algorithm DiCa[8]. The object of the new anticollision algorithm is to enhance the throughput and embody more impartiality. The simulation proved that the throughput of the new anticollision algorithm is enhanced and the consumed energy of which is as much as DiCa. View full abstract»

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  • A UWB-based localization scheme in Wireless Sensor Networks

    Publication Year: 2007 , Page(s): 52 - 55
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1486 KB)  

    A UWB-based localization scheme using RSSI-margin Localization algorithm (RMLA) for Wireless Sensor Networks (WSN) is proposed. Specially, this localization scheme chooses every cluster of network as the basic units. Anchor nodes of each cluster use the periodic UWB signals to send their own position information. When target nodes get these information, they estimate distances to these anchor nodes by Path-Loss model. Differently, we take margin of these distances and solve the non-linear equation by Taylor series expansion. Initial value is chosen specially to improve the accuracy. Simulation result indicates this algorithm has better performance than classical algorithm. View full abstract»

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  • A new code-division multiple access protocol for underwater acoustic network

    Publication Year: 2007 , Page(s): 56 - 59
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2160 KB)  

    The paper proposes a new multiple access protocol for underwater acoustic network, which uses a kind of special-designed combined synchronization header to identify different users and process user's data. By using the CDMA technology, the combining design of different synchronization header and parallel processing of the received collided packet data, the scheme can not only improve the throughput of the network, but also solve the collision problem. Therefore, the performance of the network is greatly improved. View full abstract»

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  • The design and implementation of control logic for a sensor oriented network protocol

    Publication Year: 2007 , Page(s): 60 - 63
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1605 KB)  

    This paper presents the design and implementation of controller which based on a lightweight sensor-oriented network protocol. The controller is packed as AVALON standard peripheral for further application. It can be treated as a normal intellectual property core in project design, so that the operation on it is simplified as reading or writing on register. The test results show that the controller meets the requirements of the specification in the frame identification, arbitration, checking and so on. A follow-up application developing basement can be found easily on this controller. View full abstract»

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  • Study of localization scheme base on neural network for wireless sensor networks

    Publication Year: 2007 , Page(s): 64 - 67
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1624 KB)  

    Precise knowledge of node location in wireless sensor network yields a wide variety of profound advantages. In this paper, localization scheme base on neural network for wireless sensor networks is described. We adopt neural network to model sensor network. The trained neural network can integrate global information of the sensor network as anchor nodes character, nodes deposited, environment, etc. The results of simulation demonstrate that the location scheme can obtain higher accuracy of location estimation, requires less anchor nodes and do not affected by NLOS environment and irregularity of anchor nodes radio power. View full abstract»

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  • PDAA Mechanism: A Preemptive Distributed Address Assignment Mechanism

    Publication Year: 2007 , Page(s): 68 - 71
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1766 KB)  

    Our contribution in this paper focuses on addressing mechanism and autorouting in the tree topology. Actually, we improve on the address assignment mechanism which sponsored by ZigBee alliance. The ZigBee stack protocol is designed for sensor network which is widely used. This improved address assignment mechanism is called the preemptive distributed address assignment mechanism (PDAAM). Preemptive addressing is very useful, because in the design phase we can not predict the exact node density of the sensor networks, it is particularly suitable for the networks which contain uneven distribution of node density. Further, it gives a routing algorithm. The packet can be routed from a node to the next node in using the assignment pattern to design the nodes addresses. View full abstract»

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  • Three-layered routing protocol for WSN based on LEACH algorithm

    Publication Year: 2007 , Page(s): 72 - 75
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1500 KB)  

    Due to the limitation of power and memory size for WSN (wireless sensor networks), the routing protocol of wireless sensor networks must maintain small routing information and reduce the power consumption as much as possible. LEACH (low-energy adaptive clustering hierarchy) protocol and PEGASIS (power-efficient gathering in sensor information systems) protocol are analyzed firstly in this paper. Use for reference of the ideas used in both of the two protocols of reducing power dissipation, a three-layered routing protocol for WSN based on LEACH (TL-LEACH) is given. Then, this improved LEACH protocol is simulated and the simulation results show that TL-LEACH protocol is with greatly improved WSN lifetime than LEACH protocol. View full abstract»

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  • Energy and QoS trade-off analysis of S-MAC protocol in wireless sensor networks

    Publication Year: 2007 , Page(s): 76 - 79
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1269 KB)  

    In this paper, we present a new analytical model to study the trade-off between energy consumption and quality of service (QoS) requirement (e.g., service delay and throughput) in S-MAC protocol. Our model takes into account the impact of several factors together, including periodic listen and sleep cycle, various incoming traffic loads, the backoff mechanism in S-MAC, the queuing behavior at the MAC layer, the dependency of service delay distributions among the nodes, and the imperfect wireless channels. Simulations show that our analytical results are highly accurate in evaluating the performance of S-MAC under different traffic and channel conditions. View full abstract»

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  • Based on single-hop flow control mechanism for wireless sensor networks

    Publication Year: 2007 , Page(s): 80 - 83
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1214 KB)  

    With increasing of load in wireless sensor network, congestion will make network performance worse quickly. Network performance will be improved by introducing based on single-hop flow control mechanism for wireless sensor network, in which the former hop nodes of congestion nodes adjust flow to control flow rate coming into congestion nodes. In addition, this mechanism can keep the balance of rate between inflow and outflow in congestion nodes. View full abstract»

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  • An improved AODV routing protocol with network coding in wireless Ad Hoc network

    Publication Year: 2007 , Page(s): 84 - 87
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (936 KB)  

    This paper introduces a practical scheme in order to improve multi-hop throughput as well as to minimize packet's average end to end delay by incorporating network coding, which is at present a widely discussed technique in multicast, with AODV in wireless ad hoc networks. This scheme is simple and easily implemented with modest overhead, and the simulation results show that this scheme can achieve higher throughput and much smaller packet's average end to end delay in certain network topology. View full abstract»

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  • Inspecting system of heat transmission coefficient of building envelop based on Zigbee technology

    Publication Year: 2007 , Page(s): 88 - 91
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (789 KB)  

    Design of a wireless sensor network based on Zigbee/IEEE802.15.4 is issued. The network is used to measure thermal characteristic of building envelop. Each sensor node in the system is composed of sensors and an integrated chip CC2430. The GPRS technology is used to complete data exchanging between remote inspecting center and wireless sensor network. This system is the first application in building energy efficiency field. View full abstract»

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  • Multi-sensor data transmission based on CPLD

    Publication Year: 2007 , Page(s): 92 - 95
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (770 KB)  

    A method for realizing multi-sensor data transmission in airborne environment is presented, and ARINC429 bus can be accomplished based on the flexible configuration of CPLD. A new encapsulation method of Link16 data link protocol and ARINC429 protocol in physical layer is also introduced. Test results show that the system can achieve credible data transmission within the distance 10 m at the rate of 100 kb/s. View full abstract»

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  • BPR: A Bearing based Passive Routing for Mobile Ad hoc Network

    Publication Year: 2007 , Page(s): 96 - 99
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2234 KB)  

    Some conventional routing protocols for mobile ad hoc network (MANET), such as AODV, are not scalable because of excessive protocol overhead. We propose bearing based passive routing (BPR) which introduces geographic information into AODV. BPR takes advantages of both AODV and geo-based protocols so that it not only finds the shortest route, but also reduces the overhead of route construction. We validate BPR's feasibility through simulations, and compare it with AODV to demonstrate it is better on the metrics of delivery ratio and protocol overhead. View full abstract»

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