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High throughput satellites (HTS) is a classification for communications satellites that provide at least twice, though usually by a factor of 20 or more, the total throughput of a classic FSS satellite for the same amount of allocated orbital spectrum thus significantly reducing cost-per-bit. ViaSat-1 and EchoStar XVII (also known as Jupiter-1) do provide more than 100 Gbit/s of capacity, which is more than 100 times the capacity offered by a conventional Ku-band satellite. When it was launched in October 2011 ViaSat-1 had more capacity (140 Gbit/s) than all other commercial communications satellites over North America combined. ==Overview== The significant increase in capacity is achieved by a high level frequency re-use and spot beam technology which enables frequency re-use across multiple narrowly focused〔 spot beams (usually in the order of 100s of kilometers),〔 as in cellular networks, which both are defining technical features of High Throughput Satellites. By contrast traditional satellite technology utilizes a broad single beam (usually in the order of 1000s of kilometers)〔 to cover wide regions or even entire continents.〔 In addition to a large amount of bandwidth capacity HTS are defined by the fact that they often, but not solely, target the consumer market.〔 A majority of current High Throughput Satellites operate in the Ka band, however this is not a defining criterion, and there are Ku band HTS projects in development. Despite the higher costs associated with spot beam technology, the overall cost per circuit is considerably lower as compared to shaped beam technology.〔 While Ku band FSS bandwidth can cost well over $100 million per gigabit per second in space, HTS like ViaSat-1 can supply a gigabit of throughput in space for less than $3 million. While a reduced cost per bit is often cited as a substantial advantage of High Throughput Satellites, the lowest cost per bit is not always the main driver behind the design of an HTS system, depending on the industry it will be serving.〔http://www.nsr.com/news-resources/the-bottom-line/hts-paradigm-shift/〕 HTS are primarily deployed to provide broadband Internet access service (point-to-point) to regions unserved or underserved by terrestrial technologies where they can deliver services comparable to terrestrial services in terms of pricing and bandwidth. While many current HTS platforms were designed to serve the consumer broadband market, some are also offering services to government and enterprise markets, as well as to terrestrial cellular network operators who face growing demand for broadband backhaul to rural cell sites. For cellular backhaul, the reduced cost per bit of many HTS platforms creates a significantly more favorable economic model for wireless operators to use satellite for cellular voice and data backhaul. Some HTS platforms are designed primarily for the enterprise, telecom or maritime sectors. HTS can furthermore support point-to-multipoint applications and even broadcast services such as DTH distribution to relatively small geographic areas served by a single spot beam. A fundamental difference to existing satellites is also the fact that HTS are linked to ground infrastructure through a feeder link using a regional spot beam dictating the location of possible teleports. By contrast teleports for traditional satellites can be set up in a wider area as their spotbeams' footprints cover entire continents and regions. Industry analysts at Northern Sky Research believe that high throughput satellites will supply at least 1.34 TBps of capacity by 2020〔 and thus will be a driving power for the global satellite backhaul market which is expected to triple in value – jumping from the 2012 annual revenue of about $800 million to $2.3 billion by 2021. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「high throughput satellite」の詳細全文を読む スポンサード リンク
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