Sökning: "High altitude platforms"

Hittade 3 avhandlingar innehållade orden High altitude platforms.

  1. 1. Coexistence, Deployment and Business Models of Heterogeneous Wireless Systems Incorporating High Altitude Platforms

    Författare :Zhe Yang; Blekinge Tekniska Högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wireless communication; Coexistence; High altitude platforms; Resource sharing; Capacity; Business model; Techno-economic;

    Sammanfattning : The increased demand for broadband communications has led to the rapid development of the conventional terrestrial and satellite wireless communications systems. One of the main challenges to next generation wireless systems is to deliver high-capacity and cost-efficient solutions to cope with an increasing usage of broadband services and applications. LÄS MER

  3. 2. Space-Time Processing Applications for Wireless Communications

    Författare :Tommy Hult; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Space-Time Processing; Polarization; MIMO; Diversity; HAP;

    Sammanfattning : Wireless mobile communication networks are rapidly growing at an incredible rate around the world and a number of improved and emerging technologies are seen to be critical to the improved economics and performance of these networks. The technical revolution and continuing growth of mobile radio communication systems has been made possible by extraordinary advances in the related fields of digital computing, high-speed circuit technology, the Internet and, of course, digital signal processing. LÄS MER

  4. 3. On direct hydrogen fuel cell vehicles : modelling and demonstration

    Författare :Kristina Haraldsson; Per Alvfors; Dougal J. Nelson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical engineering; direct hydrogen; Proton Exchange Membrane; PEM; fuel cell; fuel cell vehicle; fuel cell hybrid vehicles; on-board hydrogen storage; Kemiteknik; Chemical engineering; Kemiteknik;

    Sammanfattning : In this thesis, direct hydrogen Proton Exchange Membrane (PEM) fuel cell systems in vehicles are investigated through modelling, field tests and public acceptance surveys. A computer model of a 50 kW PEM fuel cell system was developed. The fuel cell system efficiency is approximately 50% between 10 and 45% of the rated power. LÄS MER