{"title":"Adaptive antenna system for PACS","authors":"S. Sandhu, A. Paulraj","doi":"10.1109/MILCOM.1997.646728","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.646728","url":null,"abstract":"The PACS (Personal Access Communications System) has been standardized as a TDMA air interface for microcellular networks operating in the PCS band (1850-1990 MHz). In order to meet performance requirements, the standard suggests use of a simple dual diversity antenna system at the radio port (base station) and subscriber unit (mobile). Space-time signal processing can be used to enhance the PACS system, improving its coverage and capacity. We propose a hybrid transceiver architecture consisting of switched antennas and adaptive combining. The receiver at the radio port consists of a multiple sectored antenna array, a switch that selects the best two antennas, and an adaptive combiner for the two selected outputs. Transmission takes place on the best receive antenna. The receiver at the subscriber unit consists of two omnidirectional antennas and an adaptive combiner. Transmission takes place on the best antenna determined by word error feedback from the radio port. We present simulation results for the proposed architecture and describe the potential improvements in coverage and capacity.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115295769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The EAST project (Euro African Satellite Telecommunications) - an opportunity for the armed forces to use commercial satcom system","authors":"B. Troy","doi":"10.1109/MILCOM.1997.646759","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.646759","url":null,"abstract":"The satellite communication world is rapidly evolving towards an extensive diversification of offered services. Under the pressure of public or private demand, commercial market growth incites investors, service providers, operators and system designers to elaborate innovative satcom projects capable of satisfying a wide range of potential users. It seems unthinkable that the military community shouldn't seek to take advantage of the attractive capabilities offered by these emerging systems either as standard subscribers, or as specific users. The paper presents one of these new projects, named EAST (Euro African Satellite Telecommunication), developed under an initiative of Matra Marconi Space and destinated to offer mobile and fixed communication services. After a description of the system architecture and performance, what the military may expect from the system is discussed.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115706173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Design considerations for mobile wideband wireless network architectures","authors":"M. Humphrey","doi":"10.1109/MILCOM.1997.646702","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.646702","url":null,"abstract":"The paper discusses aspects of high speed terrestrial ATM transmissions in a mobile environment. It includes both near term and far term goals of high speed terrestrial ATM transmissions to provide an extension of the fiber based network. The wireless video, voice, and data communication services will make possible new capabilities for information distribution. The rapid advancement of commercial technology has allowed the consideration of placing advanced technology in the mobile battlefield environment. Two possible environments are described: (1) short-range, low-mobility, and (2) long-range, high-mobility. The high speed communication links will allow video teleconferencing, video image retrieval, real-time video and other high information content services. The use of ATM cells for this study has been made, because ATM currently is believed to be the high speed technology of the future. At the proposed RF carrier frequency of 5 to 30 GHz the use of repeaters is required to provide coverage for wide geographical areas. Both ground and airplane based repeaters are explored for their capabilities, ease-of-use and liabilities. Repeater-routing within a wireless ATM mobile network is discussed. Although the high RF frequencies require the use of repeaters, they do offer the advantage of small antenna size. For high data rate communications to be successful, methods for reducing the deleterious effects of dispersion and fading must be developed. In particular, the benefits and costs of implementing an orthogonal frequency division multiplexing (OFDM) high data rate network are discussed. A suggested modulation constellation for the OFDM subcarriers is discussed. In the area of FEC, the use of turbo codes is examined.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"2013 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121515030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A DSP based bit-synchronization algorithm","authors":"T. Loos","doi":"10.1109/MILCOM.1997.644997","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.644997","url":null,"abstract":"This paper describes a software based bit-sync algorithm implemented on a fixed point digital signal processor (DSP). This implementation is used to process the audio output from a radio. It is a minimal hardware implementation. It employs a bit-sync algorithm which is a modification of the lead-lag digital phase-lock loop (LL-DPLL) algorithm of Cessna and Levy (1972).","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123500976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An overview of videoconferencing technology","authors":"G. Paul","doi":"10.1109/MILCOM.1997.648702","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.648702","url":null,"abstract":"Videoconferencing has progressed from being an expensive system used only by large corporations, to units which rapidly are becoming commodity items. This progress has been due to developments in terminal equipment, transports, and standards. This paper presents an overview of the latest developments and technology trends for group and desktop videoconferencing systems, and for circuit switched and packet switched transports. This paper also includes developments in multipoint and inverse multiplexing technologies and also presents an overview of the salient ITU-T standards for videoconferencing.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124938024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fast propagation predictions for HF network simulations","authors":"E. Johnson","doi":"10.1109/MILCOM.1997.648729","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.648729","url":null,"abstract":"The complexity of current HF radio networks (such as the SCOPE Command HF Global Communications System) has renewed interest in techniques for efficiently simulating long-haul HF radio networks. Because the dynamic propagation effects of skywave paths are the distinguishing characteristic of HF network simulations, we need to accurately simulate the connectivity among HF stations. Predictions of ionospheric propagation are typically very costly in either time or memory or both. There is a clear need for accurate, efficient techniques to predict the path losses between pairs of HF stations. This paper describes a suite of techniques that has been developed and applied to simulations of large networks of fixed and mobile radios. These techniques approximate the accuracy of the best propagation prediction programs while minimizing both the memory and CPU time used during a simulation. The paper discusses the accuracy of the predictions along with the memory requirements and running time of the new propagation prediction techniques.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124346441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Test facility for SHF (C and Ku-band) satellite communications","authors":"J. Fleming, D. Meadows","doi":"10.1109/MILCOM.1997.646758","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.646758","url":null,"abstract":"As commercial satellites become a more significant part of the U.S. Government's communications infrastructure, there develops a need for facilities where new systems and products to be used and integrated with the commercial assets can be tested and accredited. This paper describes a test facility that can facilitate rapid deployment of new technologies to the digital battlefield in a realistic environment which is non-interfering with operational satellite communications facilities. The C and Ku-band facility could be integrated with existing U.S. Government SHF SA TCOM capabilities to complement established X-band testing facilities. The components that would comprise a commercial satellite communications testbed are described. The paper also addresses near-term applications for the facility and its part in an expanding use of commercial satellites for government communications needs.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124077000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An ATM simulation system with realistic traffic modeling","authors":"D.A. Junkins, Chia-Jiu Wang","doi":"10.1109/MILCOM.1997.644979","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.644979","url":null,"abstract":"Asynchronous transfer mode (ATM) technology has promised to support multiple traffic types over a single network. The problem thus far has been to support different traffic types while maintaining the proper quality of service (QoS) parameters for all types of traffic. This paper describes a simulation system that allows the analysis of realistic integrated traffic patterns in ATM networks. The system is extensible to support new traffic patterns and can emulate most current ATM switch architectures. Different traffic patterns, buffering schemes, and traffic policing strategies are implemented in the simulator. Traffic streams composed of a constant bit rate stream, a variable bit rate stream and a available bit rate stream are used as inputs to the simulator to evaluate ATM network performance in terms of QoS parameters. The leaky-bucket algorithm is also used in the simulator for traffic policing and shaping. Simulation results of a variety of conditions are presented in this paper. Of particular interest is the simulation of both partial packet discard and early packet discard algorithms for efficient transmission of Internet protocol datagrams over ATM. Simulation results show that early packet discard can reduce network link utilization by up to 10% under heavy loads by eliminating traffic that is destined to be discarded by the receiving host.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"7 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128423894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A distributed trunking mechanism for ad hoc VHF tactical networking","authors":"S. Vitebskiy, J. Kroon","doi":"10.1109/MILCOM.1997.645018","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.645018","url":null,"abstract":"Current tactical communication systems require new approaches to provide adequate support for the growing number of services on a digital battlefield. The RF Communications Division of Harris Corporation has been developing a networking solution to meet these requirements. As a part of this solution, a robust, fully distributed protocol for VHF multi-frequency channel access has been designed. This protocol satisfies the mobility, capacity and integrated voice and data transfer requirements of the tactical environment without a fixed infrastructure. This paper presents an overview of the proposed distributed trunking mechanism, including network and node behavior and data movement. Throughput and delay performance of the protocol obtained using OPNET network in realistic tactical environments is presented.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128861077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An adaptive-rate anti-jam system for optimal voice communication","authors":"J. Kleider, W. I. Campbell","doi":"10.1109/MILCOM.1997.644870","DOIUrl":"https://doi.org/10.1109/MILCOM.1997.644870","url":null,"abstract":"Systems for the digital transmission of voice have traditionally been fixed rate in anti-jam situations. This design severely limits the potential of the communication system in the case of voice since compression of speech is a lossy process. Bit errors in the transmission of voice coded speech cause degradation which can be compensated for in several ways. The standard method is to trade off channel coding and source coding bit rates to achieve an accepted level of quality in a fixed rate system. We present a method that provides optimal voice quality and intelligibility for any given transmission channel condition. The approach is performed via a fully adaptive-rate system using an adaptive-rate modem, channel coding, and a multimode voice coder. In general, the receiver utilizes channel state information to not only optimally demodulate and decode the currently corrupted symbols from the channel, but also to inform the transmitter, via a feedback channel, of the optimal strategy for voice/channel coding and modulation format. We compare several joint source-channel coding schemes at multiple transmission symbol rates and compare the performance to fixed aggregate-rate channel-controlled variable rate voice coding systems. We show through simulation that the reduction in speech distortion is greater for a modulation change than a channel coding change in many realistic situations because of the variability of coding gain.","PeriodicalId":351392,"journal":{"name":"MILCOM 97 MILCOM 97 Proceedings","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129723685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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