By Topic

Universal Personal Communications Record, 1997. Conference Record., 1997 IEEE 6th International Conference on

Date 12-16 Oct. 1997

Go

Filter Results

Displaying Results 1 - 25 of 120
  • 1997 IEEE 6th International Conference on Universal Personal Communications Record

    Publication Year: 1997 , Page(s): i - xxvii
    Save to Project icon | Request Permissions | PDF file iconPDF (646 KB)  
    Freely Available from IEEE
  • Author index

    Publication Year: 1997 , Page(s): 934 - 936
    Save to Project icon | Request Permissions | PDF file iconPDF (189 KB)  
    Freely Available from IEEE
  • Spatial-temporal diversity technique based on fractionally-spaced adaptive array antenna

    Publication Year: 1997 , Page(s): 828 - 832 vol.2
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB)  

    For the array processing in a wireless network a spatial diversity method is used to increase the system capacity. It obtains spatial-temporal diversity by using the equalizer or the RAKE receiver jointly. In this paper, we analyze the effect of a fractionally-spaced (FS) array antenna, which can attain performance enhancement and insensitivity to timing phase without increasing the number of antennas. The FS antenna array system is thought to be a joint poly-phase filter bank which consists of that of the time-domain and space-domain. As a result, the performance of the FS array antenna is similar to that of the symbol-spaced array antenna with more antennas View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Interference cancellation schemes for a dual-rate variable processing gain DS/CDMA system

    Publication Year: 1997 , Page(s): 465 - 469 vol.2
    Cited by:  Papers (2)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB)  

    The existing multi-stage interference cancellation (IC) schemes have been extended to be specialized for the dual-rate DS/CDMA system with variable processing gains subject to the graded power control. The bit error rate performance using these IC schemes for the dual-rate DS/CDMA system is analytically derived under a frequency non-selective fading channel. Numerical examples in this analysis demonstrate that the rate-dependent near-far effect can be effectively eliminated with the proposed approaches under unfavorable situation of the graded power control, which incurs additional interference in the variable processing gain DS/CDMA system View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Time resolution-signal-to-noise ratio trade-off in deconvolved and Wiener filtered radio channel sounding

    Publication Year: 1997 , Page(s): 833 - 837 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    It is an often anticipated fact that the time resolution of direct sequence-type radio channel sounding is limited only partially by the sounding sequence chip duration. We have previously introduced a computationally efficient and noise resistant method to achieve a time resolution approaching sample time called matched filter deconvolution (MFD). This paper considers additional effects of Wiener filtering when used with the MFD method. Our simulations show how filtering trades SNR to time resolution and how this trading reacts on sampling rate/sequence rate ratio. Based on this analysis we suggest Wiener filtering to be considered when deconvolving radio channels having poor SNR and/or when channel measurement results should be used for playback channel simulations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A model for teletraffic performance and channel holding time characterization in wireless cellular communication

    Publication Year: 1997 , Page(s): 671 - 675 vol.2
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    Channel holding times and user mobility are important topics in the study of wireless cellular communications. The dependency of holding time on user mobility is discussed. We give an approach to modeling user mobility which enables the calculation of teletraffic performance characteristics and a characterization of holding time which agrees with published reports. A derivation of the channel holding time distribution based on previous work is given. We then show how user mobility parameters can be chosen to fit empirical data including observations of channel holding time View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An asynchronous time division multiplexing-multiple access protocol for indoor wireless multi-service networks

    Publication Year: 1997 , Page(s): 918 - 922 vol.2
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB)  

    This paper describes an asynchronous time division multiplexing-multiple access (ATDM-MA) protocol which is designed to support different types of service on future wireless indoor local area networks. The proposed architecture does not follow the conventional cellular or ad-hoc approaches but supports both peer-to-peer communication and infrastructure access. It is assumed that a high bit rate (20 Mbit/s) radio solution is used to provide the physical connectivity with omnidirectional antennas. The goal of the ATDM-MA protocol is to provide efficient channel utilisation and re-use and operates in conjunction with different medium access control (MAC) protocols for different traffic types (i.e. polling and random access). The throughput and delay of the proposed scheme obtained from computer simulation shows that good performance can be achieved with modest complexity View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effect of non-uniform traffic distributions on performance of a cellular CDMA system

    Publication Year: 1997 , Page(s): 598 - 602 vol.2
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    This paper presents a study of the effect of nonuniform user traffic distributions on the performance of a CDMA cellular system. While, there have been many studies showing the capacity gains of CDMA over narrowband TDMA systems, most of these studies assume a uniform distribution of the user population across the coverage area. When compared to the more general case of non-uniform user distributions, the uniform user distribution leads to lower multi-user interference and consequently higher system capacity. Hence, use of these models can lead to overestimation of system capacity. Three non-uniform user density models are developed and used to analyze the system's performance in typical CDMA implementation scenarios. The results indicate that intra-cell multi-user interference dominates the total interference levels in most cases. As expected cell splitting is shown to improve the system performance. The most significant improvements in performance with cell-splitting are seen for a Gaussian user density model (when compared to linear or exponential user density models). The results provide additional insight into the performance of CDMA systems, and are useful for the purposes of network planning and resource allocation View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of a simple PCS network with nonuniformly distributed mobile users

    Publication Year: 1997 , Page(s): 572 - 576 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    A traffic performance model and analytical method are proposed for mobile communication systems that have nonuniform offered traffic. Nonuniformity of user distribution should be taken into account when a system is designed. New system state variables are introduced to analyze such situations. These represent the number of active calls of each kind as well as their moving directions and hand-off experience. System state probabilities are determined and used to calculate the traffic performance of the system. The blocking probability and carried traffic for each cell and forced termination probabilities corresponding to a call's origination cell are presented. Numerical results are also presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Characterization of signal polarization near 900 MHz in and on vehicles and within buildings

    Publication Year: 1997 , Page(s): 838 - 842 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    Dominantly horizontally polarized antennas are being used in hand-held devices operating near 900 MHz, and their performance when used to communicate with vertically polarized base station antennas is of great interest. An automated system was constructed to measure the received signal strength from 4 antennas: three orthogonally oriented dipole antennas, and a circularly polarized omni-directional antenna. Three sets of measurements were taken: one in a vehicular environment and two in building environments. Measurements were taken inside the front of a van and on the roof of the van. The indoor measurements were performed in a two story office building at varying heights while stationary and at a constant height while moving View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bandwidth reservation for multimedia traffic over micro cellular network

    Publication Year: 1997 , Page(s): 761 - 765 vol.2
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    Supporting multimedia traffic over wireless channels in a cellular network requires effective control of the channel's limited capacity. The challenge is to guarantee different quality of service (QoS) parameters for different types of traffic while achieving high throughput. The performance of a bandwidth reservation multiple access (BRMA) protocol is studied for multimedia traffic. BRMA reserves a minimum bandwidth for each mobile station (MS) during the call setup. Admission control rejects any connection request from any MS for which QoS is not guaranteed. Inside any uplink time frame, mini slots are assigned deterministically to each MS whereas data slots are assigned by the base station (BS). These guarantee the efficient operation of the protocol View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An optimal self-learning estimator for predicting inter-cell user trajectory in wireless radio networks

    Publication Year: 1997 , Page(s): 438 - 442 vol.2
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    Prediction of the next-crossing cell is an important issue for mobility and connection management in wireless radio networks. We propose a new approach to modeling inter-cell user mobility, and develop an optimum self-learning estimator for trajectory tracking and next-crossing cell prediction. The dynamic states of movement, in terms of speed and position, are obtained by modeling the user's acceleration as a time correlated, semi-Markovian process, and by passing subsequent signal-strength measurements to neighboring base stations through an extended, self-learning Kalman filter. Prediction of next-crossing cell is obtained by evaluating user dynamic states with cell geometry. Analysis and simulation results show that our prediction algorithm is robust in the presence of pass loss, shadow fading, and random movement, being able to predict the position, speed, and direction-of-travel of the mobile user with a high degree accuracy View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A combined channel assignment strategy in a hierarchical cellular systems

    Publication Year: 1997 , Page(s): 651 - 655 vol.2
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    This paper proposes a combined channel assignment (CCA) strategy for a hierarchical cellular system. The proposed CCA strategy combines overflow, underflow, and reversible techniques, where new or handoff calls having no available channel to use in the overlaid microcell can overflow to use free channels in the overlaying macrocell, handoff calls from neighboring macrocell can underflow to use the free channel in the microcell, and handoff attempts from overlaying macrocell to overlaid microcell are reversed to use free channels in the microcell if there are idle channels in the microcell. In the simulation, we further compare the CCA strategy with the overflow channel assignment (OCA) scheme and investigate two different hierarchical cellular systems of Strip type and Manhattan type. From simulation results, it is shown that the new-call blocking ratio and forced termination ratio are decreased and the CCA strategy outperforms the OCA scheme View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Efficient despreaders for multi-code CDMA systems

    Publication Year: 1997 , Page(s): 516 - 520 vol.2
    Cited by:  Papers (8)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    It is shown that the implementation efficiency of the despreaders for multi-code CDMA systems directly depends on the efficiency of elementary bank of correlators corresponding to the applied binary spreading sequences, regardless of the spreading and modulation format. Until now two kinds of spreading sequences are proposed for the application in the multicode transmission schemes: sets of Walsh sequences and sets of orthogonal Gold (1967) sequences. The paper presents the efficient implementation of the bank of correlators matched to the set of orthogonal Gold sequences. The method of finding all the permutations which map the orthogonal Gold sequences into the Walsh sequences is also shown View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High rate data communication via power distribution network using DS-CDMA technique

    Publication Year: 1997 , Page(s): 805 - 808 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB)  

    The use of power distribution networks for communication is becoming more and more important due to the need for new transmission lines. This could solve the difficulty of connecting a single user to a higher level network because low tension powerlines end in every room of every flat. In this paper a system is presented which offers a high data rate to each user. It is based on the direct sequence spread spectrum technique (DS-CDMA). The principles for such a power line communication system have been presented previously. Based on that a hardware realisation was built up by the authors to investigate the achievable bit error rate. The presented measurements of transmission characteristics of the low tension network are the foundations for simulating the proposed communication system. All investigations confirm that the presented transmission scheme is suited for establishing a high data rate communication via low tension powerlines View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance evaluation of type-of-service based directed retry strategy in cellular mobile networks

    Publication Year: 1997 , Page(s): 676 - 680 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    Type-of-service based directed retry strategy is investigated to achieve efficient channel utilization for different types of users in mobile cellular environments. Directed retry takes advantage of inevitable overlap among cells to increase the channel utilization and reduce the blocking probability in each cell. A M/M/m/k queue is used to model the channel occupancy statement. Several parameters, such as traffic load, queue length, blocking probability and overlapped area fraction, are studied for comparisons among different types of users, e.g., delay-sensitive and delay non-sensitive. Additional handoff processing load, which is due to directed retry and related to overlapped area fraction and mean path length, is estimated. The results show that the additional handoff probability caused by directed retry is quite small, even in the case of delay-sensitive services View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dynamic mobility tracking for wireless personal communication networks

    Publication Year: 1997 , Page(s): 448 - 452 vol.2
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    A dynamic mobility tracking scheme is developed to minimize the cost of mobility tracking by optimally partitioning the service area into location registration (LR) areas on a per-user basis. This cost is affected by the mobility and call pattern of the individual subscriber, as well as the size and the orientation of the LR area. A more realistic mobility model is proposed in which we take not only the mobility behavior of individual subscriber but also the street layout into consideration. Based on this model, a transient Markov process is developed to analyze the tracking cost View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Potential of the GSM air interface to support CDMA operation

    Publication Year: 1997 , Page(s): 883 - 887 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    An important issue in the development of third generation systems is the need for compatibility with the existing second generation systems. This paper considers the feasibility of supporting CDMA operation within the GSM air interface in order to provide UMTS capabilities. It produces performance estimates for two specific examples: joint detection CDMA channels, and multicarrier DS-CDMA channels. It is shown that a number of advantages can be obtained by using a hybrid CDMA scheme View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance simulation of call capacity for base station in CDMA mobile system

    Publication Year: 1997 , Page(s): 603 - 607 vol.2
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (656 KB)  

    The performance of call capacity for the base station (BS) in the CDMA mobile system (CMS) is analyzed, and the simulation results are compared with the analytical results. Also, the bottleneck points and problems which may occur in the BS are pointed out. For analyzing the call capacity, the major parameters for the modeling the BS are extracted and the simulation model for the BS is suggested. The simulation results are estimated by finding major objective factors such as the blocking probability, the utilization ratio and the delay time in the traffic channel elements (TCEs), the CDMA interconnection network (CIN) packet router, the base transceiver subsystem (BTS) interconnection network (BIN)-GIN trunks and the transcoding channels View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Tracking agent: a new way of communication in a multi-agent environment

    Publication Year: 1997 , Page(s): 903 - 907 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    We propose a communication scheme for multi-mobile-agent system. A mobile-agent is a process moving in a network to execute a task specified by a user. When one of the cooperating agents moves to a new location, it needs to make a new connection to the other agents. Communications by broadcasting is not very efficient. We propose a new agent named “tracking agent”, which tracks locations of mobile-agents, so that a mobile-agent does not need to care about the movements of the other mobile-agents View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An adaptive hybrid FEC/ARQ protocol using turbo codes

    Publication Year: 1997 , Page(s): 541 - 545 vol.2
    Cited by:  Papers (4)  |  Patents (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    This paper describes a type-II adaptive hybrid FEC/ARQ protocol using turbo codes. Both voice and data services are considered. Recently, a powerful family of error correcting codes using parallel concatenated convolutional codes is introduced. Near-Shannon-limit is achievable by such codes. For example, a bit error rate of 10-5 ; can be achieved at Eb/No 0.7 dB using a rate 1/2 code or at about 2.5 dB if fewer iterations are used in decoding. Given the promising performance of the codes, it is expected that the performance of an adaptive FEC/ARQ protocol employing turbo codes will be better than protocols using other error correcting codes. For real-time services, the number of retransmissions is limited to one so as to limit the delay. For data services, the number of retransmissions is unlimited to provide a reliable communication link. Results in terms of throughput are obtained through analysis and approximation using the performance curves View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Stored media synchronization schemes in ATM and wireless networks: a performance comparison

    Publication Year: 1997 , Page(s): 766 - 772 vol.2
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB)  

    This paper compares four schemes of lip synchronization control between voice and video for stored media transmission. Two out of the four interleave voice and video to form a single transport stream for transmission (single-stream approach). The other two set up separate transport streams for the individual media streams (multi-stream approach). In each of the two approaches, we have the alternative of exerting the control or not. We implemented the four schemes on an ATM LAN and on an interconnected ATM-wireless LAN under the TCP protocol. The mean square error of synchronization, total pause time, throughput and total output time were measured in each of the schemes to find out which scheme is the most suitable for a given condition of the underlying communication network and traffic View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A performance bound for interference adaptation dynamic channel allocation in wireless communication networks

    Publication Year: 1997 , Page(s): 656 - 660 vol.2
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    Interference adaptation dynamic channel allocation (IA-DCA) schemes have been shown by several researchers to be a promising channel assignment method. However, these investigations were nor supported by theoretical studies. This paper attempts to fill that void. In order to analyze the performance of IA-DCA in the optimum case, a concept called channel reuse zone is introduced and an idealized interference adaptation maximum packing method is proposed. We derived a performance bound for IA-DCA in forward link by using this method with a simplified propagation model View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Channel shadowing considerations for fixed wireless access schemes

    Publication Year: 1997 , Page(s): 843 - 847 vol.2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    This paper examines the consequences of the statistical distribution of shadowing loss in the case of comparatively low base station antennas, and particularly in the case of fixed wireless access systems. The log-normal distribution typically assumed for the mobile case is justified, and arguments presented for the standard deviation to be a function of distance. The correlation in the shadowing loss to different base stations is then considered, and the effects quantized in terms of typical interference levels. Results show that consideration of the correlations in shadowing losses has a significant impact on the choice of a power control scheme View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new routing protocol for the reconfigurable wireless networks

    Publication Year: 1997 , Page(s): 562 - 566 vol.2
    Cited by:  Papers (96)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    We propose a new routing protocol, the Zone Routing Protocol (ZRP), for the reconfigurable wireless networks, a large scale, highly mobile ad-hoc networking environment. The novelty of the ZRP protocol is that it is applicable to large flat-routed networks. Furthermore, through the use of the zone radius parameter, the scheme exhibits the adjustable hybrid behavior of proactive and reactive routing schemes. We evaluate the performance of the protocol, showing the reduction in the number of control messages, as compared with other reactive schemes, such as flooding View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.