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Personal Wireless Communications, 2000 IEEE International Conference on

Date 17-20 Dec. 2000

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  • 2000 IEEE International Conference on Personal Wireless Communications. Conference Proceedings (Cat. No.00TH8488)

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    Freely Available from IEEE
  • Comparison of different retransmission strategies for bandwidth efficient hybrid ARQ schemes using turbo codes

    Page(s): 548 - 552
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    In this paper, two classes of retransmission strategies in time-varying mobile radio channels are studied for bandwidth efficient hybrid-ARQ (HARQ) schemes using turbo coded modulation. These schemes combine the power efficiency of turbo codes with the bandwidth efficiency of trellis-coded modulation (TCM) to create an effective hybrid FEC/ARQ system. Different retransmission schemes provide a trade-off in terms of throughput, delay, implementation complexity, and error performance. View full abstract»

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  • Index of authors

    Page(s): 583 - 584
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  • Resource allocation in GPRS wireless networks

    Page(s): 388 - 394
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    We have proposed two algorithms for the fixed and the dynamic channel allocation schemes in GPRS. We started with a simple channel allocation problem in GPRS and showed that it is closely related to the one-dimensional standard bin packing problem. We used two online bin packing algorithms, namely the first fit (FF) and the best fit (BF) algorithms, for channel allocation and obtained their performance for single slot operation, multislot operation and also for a realistic case with multislot class 21 MS. We have also analysed the fixed channel allocation, single slot operation case and analytical results are found to compare favourably with the results from simulations View full abstract»

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  • Handoff in mobile wireless ATM networks: an integrated approach

    Page(s): 52 - 56
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    Route augmentation based connection rerouting techniques for handoff provide a level of speed and simplicity that can potentially reduce handoff latency and signaling costs, but can become terribly inefficient if the connection route begins to loop itself. We address this issue in this paper by introducing a framework for efficient handoff in which the route information of the call is integrated in the decision process of connection rerouting. A key feature in our approach is that during the handoff the switch covering the mobile host determines the type of handoff that needs to be initiated based on the existing route information of the call that is being handed off and the location of the mobile host. In current handoff techniques in the literature, the switches are not capable of making such choices. This algorithm is aimed at improving the efficiency of the route in the route augmentation technique by avoiding loops View full abstract»

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  • Mobile IP for 3G wireless networks

    Page(s): 240 - 244
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    Mobile IP specifies protocol enhancements to the Internet protocol that allow transparent routing of IP datagrams in the Internet to the mobile node irrespective of its physical location. Extensions are being proposed for managing Mobile IP-based micro-mobility for the interface between a radio network and a packet data network in the third-generation cdma2000 network. We discuss the cdma2000 architecture and Mobile IP. We then propose an architecture for integrating Mobile IP and cdma2000 View full abstract»

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  • Integrating QoS support in TeleMIP's mobility architecture

    Page(s): 57 - 64
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    The paper describes a differentiated services-based QoS architecture for next-generation cellular wireless networks. The architecture is based on the two-level TeleMIP (telecommunications-enhanced mobile IP) hierarchical mobility management scheme and integrates bandwidth broker-based admission control and resource provisioning for mobile nodes. The TeleMIP architecture is extended to satisfy the QoS requirements of a mobile node, while requiring it to specify its traffic profile only when it first moves into a domain. The paper explores alternative approaches for dynamically assigning mobility agents to a mobile node and evaluates their suitability for different service differentiation models View full abstract»

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  • A nonzero intermediate frequency likelihood acquisition scheme for CDMA system

    Page(s): 479 - 483
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    A nonzero intermediate frequency (IF) likelihood acquisition scheme for PN codes is introduced in this paper. The received signal is first downconverted to IF, and then direct sampled in IF using a 1-bit A/D converter. After the digitalization, the sampled data is detected using a hybrid likelihood acquisition scheme. Using this structure, problems, due to large noise figure of the analog mixer or active filters or due to amplitude and phase imbalance between low-frequency in-phase and quadrature-phase channels, can be avoided. An algorithm which allows easy implementation of the acquisition scheme is also derived. The performance and algorithm are verified by computer simulation View full abstract»

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  • A tool to calculate Erlang capacity of a BTS supporting 3G UMTS system

    Page(s): 173 - 177
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    The second-generation (2G) wireless systems are primarily designed for voice services. The cell capacity is obtained by simulation for the given mobile environment. The cell capacity is used in network planning. The proposed 3G wireless systems mainly address data services. A 3G system allows users to use multimedia services. Therefore, there can be several different combinations of the voice and data services that may occur at a base station transceiver (BTS). This will require major time-consuming simulations to obtain the Erlang capacity of the BTS for all possible combinations of the services and will complicate the network planning process. The objective of this paper is to present a simple tool that analytically models a BTS. We do not have to depend on major simulations to obtain the BTS capacity for the given set of services. We develop the Erlang capacities of a BTS for voice services, real-time (circuit-switched) and non-real-time (packet-switched) data services. We use the capacity figures of the uplink and downlink with the link budget to calculate the maximum cell radius for each service type in an urban environment. We show the effect of uplink and downlink information bit rate on the cell radius View full abstract»

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  • Dynamically adaptive channel reservation scheme in cellular networks

    Page(s): 269 - 272
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    In personal communications networks (PCN) supporting network-wide handoffs, new and handoff requests compete for connection resources in both the mobile and backbone networks. Forced call terminations due to handoff call blocking are generally more objectionable than new call blocking. In general, most of the previously proposed schemes for radio channel allocation in cellular networks reduce handoff call blocking probability substantially at the expense of increasing the new call blocking probability by giving higher priority to handoff calls over new calls in admission control. This reduces the total admitted traffic and results in inefficient utilization of wireless channels. The trade off between new call blocking probability and handoff blocking probability should be defined on importance basis. We propose a performance metric equation that makes a trade off between the two probabilities depending on the network preferences. Using this equation we study the performance of various proposed channel reservation schemes. Also, a new dynamically adaptive channel reservation scheme (DACRS) is developed and compared with the various channel reservation schemes. The DACRS assigns handoff-reserved channels to new calls depending on the locality principle of the GSM in which the base station can know the position of the mobile terminal. Eventually, the DACRS is designed to improve channel utilization while satisfying the QoS of all calls. As is shown by the simulation results, the new DACRS outperforms current reservation schemes and results in more statistical gain, and powerful decisions for handoff reservation View full abstract»

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  • Self-organizing, self-healing wireless networks

    Page(s): 355 - 362
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    Self-organizing, self-healing networks, also called “ad hoc” networks, are perhaps the most exciting new trend in networking research and development. Every node in such a network has sufficient intelligence to continuously sense and discover other nearby nodes, dynamically determine the optimal path for forwarding data packets from itself hop by hop through the network to any other node in the network, and automatically heal any ruptures in the network fabric that are caused by ongoing movement of the nodes themselves, changes in RF propagation, destruction of nodes, etc. In essence; one need merely launch such radio nodes into some space and they will not only organize themselves into a network but also adapt continuously to changes in the network's connectivity. The field is currently evolving at “Internet speed” - the first large-scale systems are now being fielded into the USA military and yet many of the field's research fundamentals are at present only very poorly understood. This paper begins with an example that introduces some of the fundamental issues for ad hoc networks (hidden terminals, channel access, mobility, scalability, and power constraints). It then discusses the two dominant approaches in current ad hoc networking technologies, “proactive” and “on-demand” path discovery, and compares the strengths and weaknesses of each approach. The paper then presents two brief case studies with which the authors were intimately involved - of a 400-node, terrestrial, vehicle-based system and of a high-capacity voice and data network deployed among drone aircraft - and concludes with highlights of the current research topics in the field View full abstract»

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  • A method of data transfer control during handoffs in mobile multimedia networks

    Page(s): 65 - 69
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    In this paper, a new data transfer control scheme is proposed to provide a high degree of data transfer during handoffs for multimedia traffic carried in microcellular, picocellular, and high speed wireless networks. The method performs efficient buffering of the data at the base station using toggled buffers. The method has been tested on in-house wired/wireless networks. The results have shown enormous improvement in the continuity of data transfer during multiple handoffs while running multimedia applications such as video-on-demand (VoD) and audio-on-demand (AoD) View full abstract»

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  • Combined Huffman code, row and column array code and phase/frequency modulation

    Page(s): 383 - 387
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    A technique for combining Huffman code, row and column array (RAC) codes and phase/frequency modulation in order to reduce redundancy, provide error protection and simultaneously to optimise channel bandwidth is presented. It is shown that this scheme provides a reduction in overall complexity as compared to that employing a demodulator followed by a trellis decoder of RAC code and a Huffman decoder. The trellis of the combined codes employing BFSK/MPSK modulation are designed and implemented and their error performances are compared with those employing coded as well as uncoded MPSK modulation. The proposed block coded modulation (BCM) scheme is suitable for both data transmission and information storage View full abstract»

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  • Strategies for resource allocation in wideband CDMA networks for high data rate applications

    Page(s): 273 - 277
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    Present generation wireless networks are being designed considering voice as the primary traffic. They are not suitable to support high data traffic rate. Third-generation standards are proposed to meet the increasing data traffic demand over mobile telephones. Wideband code division multiple access (WCDMA) is a promising technique for radio access in future cellular networks and personal communication systems. This paper deals with the problem of resource allocation in the forward link for wideband CDMA networks. Three types of user classes are assumed with data rate of 9.6 kbit/s, 144 kbit/s and 384 kbit/s respectively. A mixed dynamic and static algorithm is proposed, under the constraint that the base station is total transmitted power-limited. The performance of different classes of traffic is compared. A comparative study for voice and data traffic has been carried out View full abstract»

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  • Efficient channel assignment algorithm under cochannel and adjacent channel interference constraint

    Page(s): 424 - 428
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    Channel assignment is the key to spectrum management. In this paper, the channel assignment problem is modeled as a graph coloring formulation. The task of assigning a limited number of channels to transmitters under a set of constraints in an efficient way is an NP-complete optimization problem. We apply a powerful metaheuristic search algorithm, namely a simulated annealing algorithm together with a sequential algorithm, to tackle this type of problem. In order to evaluate the performance of the methodology, the algorithm is tested on a number of benchmark problems and the results are compared with the existing ones for the same set of constraints. It is found that the results obtained by our approach are comparable to those obtained by existing methods View full abstract»

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  • Frequency offset sensitivity reduction of multicarrier transmission by waveshaping

    Page(s): 444 - 448
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    This paper addresses the reduction of system sensitivity to the frequency offset due to time shaping of the multicarrier (MC) signal. Rectangular and Gaussian shapes (with different spreads) are considered. For a multipath channel, degradation of the performance of the OFDM system to the frequency offset for BPSK and QPSK modulation and for these waveshapes is investigated and compared. The effect of changing the number of carriers, as well as the multipath channel delay spread, on the sensitivity reduction of OFDM with shaping is thoroughly studied. Results show that the Gaussian shaped OFDM is much less sensitive to the frequency offset than conventional (rectangular) OFDM. Reducing the time spread of the Gaussian shape reduces the sensitivity. For OFDM with both rectangular and Gaussian shapes, sensitivity to frequency offset slightly increases by increasing the number of carriers. For a waveshaped OFDM system with a fixed spread of Gaussian shapes, performance degradation due to frequency offset is higher for BPSK than QPSK. Results show that, compared with conventional OFDM with 32 carriers, the Gaussian shaped MC, with a spread width of 10% of the symbol time, reduces the sensitivity of the system to frequency offset by a factor of almost 6 dB. Results can be used in the analysis and design of high-speed digital data transmission over wireless multipath fading channels View full abstract»

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  • Comparative study of partitioned and parallel concatenated convolutional codes with puncturing

    Page(s): 212 - 216
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    We design and implement the partitioned convolutional code (PCC) and the parallel-concatenated nonrecursive convolutional code (PCNCC). A comparison of the two codes is then carried out based on the following aspects: BER, encoder and decoder complexity, effective code rate, and throughput. It is shown that the PCNCC has identical error performance to the PCC but with less hardware complexity and a slightly higher effective code rate. Also, puncturing is used to increase the code rate of the PCNCC and computer simulation results show that the best PCNCC are those in which the component encoders are derived from the basic encoder View full abstract»

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  • An optimum detector for coherent M-ary signaling in the presence of impulsive noise

    Page(s): 363 - 367
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    Digital communication systems operating in the ELF/VLF range are strongly affected by atmospheric noise which has an impulsive component on a white Gaussian background. We derive an optimum detector for coherent M-ary signaling in the presence of such noise. In the special case of coherent binary signaling, the performance of a suboptimum linear detector is analyzed View full abstract»

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  • Performance analysis of the Bluetooth physical layer

    Page(s): 70 - 74
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    Bluetooth is an emerging, short range, indoor wireless network technology, based on FH-CDMA/TDD, which allows a collection of devices to form small overlapping networks, called piconets, in an ad hoc fashion. It is likely that the Bluetooth specification may be adopted in the IEEE 802.15 Wireless Personal Area Network standard. In this paper, we present an analysis of the Bluetooth physical layer. We consider a single room office environment (LOS propagation), with a number of piconets distributed in it, In the present work we have focussed only on the interference between piconets. Assuming a uniform distribution of Bluetooth devices in the room, we provide an analysis of the outage probability as a function of the number of overlapping piconets. We then characterise the temporal correlation in the outage process. This leads to an approximation for the mean outage duration. Combining the outage probability with the mean outage duration, we provide a 2-state Markov model for the Bluetooth channel View full abstract»

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  • Measurement and characterization of broadband MIMO fixed wireless channels at 2.5 GHz

    Page(s): 203 - 206
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    We study the channel typical for cellular broadband fixed wireless applications. A measurement system for a two-element-transmit by two-element-receive antenna configuration was built, Measurements were conducted in a suburban environment with dual antenna polarization and transmit separation. We present results on K-factor, cross-polarization discrimination (XPD) and Doppler spectrum. Our results address the influence of distance and antenna height for K-factor and XPD. We also comment on the properties of a fixed wireless channel and describe its Doppler spectrum View full abstract»

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  • Minimum duration outage analysis of cellular CDMA for integrated services with correlated signal and interference

    Page(s): 254 - 258
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    Minimum duration outage analysis has been carried out for a cellular system supporting both voice and data services. The outage has been defined as the excursion of SIR (signal-to-interference ratio) below a threshold level for a certain minimum duration. A mathematical formulation with closed form expression for minimum duration outage considering the correlation between the signal and interference is presented. The capacity of the system in terms of the number of users is related to minimum duration outage probability considering an appropriate interference model View full abstract»

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  • A comparison study between different sliding window decorrelating detectors for asynchronous CDMA-UMTS

    Page(s): 114 - 117
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    Among the different receiver architectures which are able to cope with the multiple access interference (MAI) impediments, the decorrelator structure based on linear filtering is a good potential solution since it leads to a near-far resistant algorithm in CDMA systems with a moderate complexity. However, since, the ideal asynchronous decorrelator requires the observation of the entire input bit sequence, it is not suitable for practical applications. In this paper, we propose some methods using correction for both edges of the finite observed window View full abstract»

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  • Intrusion tolerance schemes to facilitate mobile e-commerce

    Page(s): 514 - 518
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    In this paper, we concentrate on one aspect of information system security, namely that of intrusion tolerance. An intrusion tolerant system is one that continues to function correctly and provide the intended user services in a timely manner even in the face of an information attack. In this paper we concentrate on a technique called fragmentation-redundancy-scattering and investigate how this technique can be used in a mobile environment. We also provide different schemes towards ensuring intrusion tolerance in a mobile system View full abstract»

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  • Outage analysis of cellular CDMA for integrated voice and data services with correlated signal and interference

    Page(s): 249 - 253
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    Probability of outage is an important parameter for capacity evaluation of a cellular CDMA system. A mathematical formulation with closed form expression for outage probability for integrated voice and data services has been proposed. The correlation between signal and interference is also considered in evaluating the outage. It is observed that considering the correlation a significant reduction in outage probability is obtained compared to the model of Ayyagari et al., 1999 View full abstract»

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  • Demodulation of BFSK signals by adaptive digital notch filtering

    Page(s): 217 - 219
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    We analyze a demodulation technique in which a sampled version of a BFSK signal is passed through an adaptive digital notch filter that estimates and tracks the instantaneous frequency of the incoming signal. By smoothing of the estimated instantaneous frequency sequence followed by a hard decision, we obtain the demodulated signal View full abstract»

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