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Tham khảo tài liệu 'mobile and wireless communications physical layer development and implementation part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | High Altitude Platforms for Wireless Mobile Communication Applications 51 An US compnay Sanswire Technologies Inc. Fort Lauderdale USA and Angel Technologies St. Louis USA carried out a series of research and demonstrations for HAP practical applications. The flight took place at the Sanswire facility in Palmdale California on Nov. 15 2005. These successful demonstrations represent mature steps in the evolution of Sanswire s overall high altitude airship program. Engineers from Japan have demonstrated that HAPs can be used to provide HDTV services and IMT-2000 WCDMA services successfully. A few HAP trails have been carried out in the EU CAPANINA project to demonstrate its capabilities and applications CAPANINA 2004 . In 2004 the first trial was in Pershore UK. The trial consisted of a set of several tests based on a 300 m altitude tethered aerostat. Though the aerostat was not situated at the expected altitude it have many tasks of demonstrations and assessments e.g. BFWA up to 120 Mbps to a fixed user using 28 GHz band end-to-end network connectivity high speed Internet Video On Demand VoD service using a similar platform-user architecture as that of a HAP. In October 2005 the second trial was conducted in Sweden. A 12 000 cubic meter balloon flying at an altitude of around 24 km for nine hours was launched. It conducted the RF and optical trials. Via Wi-Fi the radio equipment has supported date rates of 11 Mbps at distances ranging up to 60 km. This trial is a critical step to realize the ultimate term aim of CAPANINA to provide the 120 Mpbs data rate. 3. HAP Communication System and Deployment 3.1 Advantages of HAP system HAPs are regarded to have several unique characteristics compared with terrestrial and satellite systems and are ideal complement or alternative solutions when deploying next generation communication system requiring high capacity. Typical characteristics of these three systems are shown in Table 1. Subject HAPs T errestrial Satellite Cell .
