oneweb
2019.7.16，一网在首尔开展在轨测试，最高速度400Mbps，延时32ms；地面终端由韩国Intellian生产。
https://www.oneweb.world/media-center/onewebs-satellites-deliver-real-time-hd-streaming-from-space
- OneWeb proves satellite constellation can deliver high-speed, low-latency services from Space
- Comprehensive tests delivered live Full HD (1080p) streaming video at latency of less than 40 milliseconds and with speeds of over 400 Mbps
- All satellites in orbit, launched in February 2019 are performing well
- Test conducted in partnership with Intellian, developer of OneWeb user terminals
onweb轨道高速1200km，往返距离24*10^5 / 3*10^8 = 8ms，为什么延时为32ms？考虑路径是斜的，乘以根号2，是11ms，多的21ms怎么来的？转发延时？
London, July 16, 2019 – OneWeb, whose mission is to enable internet access everywhere for everyone, is delighted to announce the successful test of its six satellites in Low Earth Orbit. All satellites delivered high-speed, low-latency services, with speed of more than 400 Mbps which enabled the fastest real-time video streaming in Full HD from Space. The tests, which took place in Seoul, South Korea, represent the most significant demonstration of the OneWeb constellation to date, proving its ability to provide superior broadband connectivity anywhere on the planet.
The recent satellite tests were conducted in partnership with Intellian, the developer and manufacturer of OneWeb user terminals and SatixFy, developer and manufacturer of the 125 MHz SCPC test modem. The tests included: latency, speed, jitter, seamless handover between satellites and power control. During its test, OneWeb demonstrated:
- Extremely low latency with an average of 32 milliseconds;
- Seamless beam and satellite handovers;
- Accurate antenna pointing and tracking;
- Live streamed video at resolutions up to 1080p (Full HD); and
- Test speed rates of more than 400 Mbps.
一网没有星间链路，是否采用IP协议未知
Starlink采用激光星间链路，但是IP-less
oneweb, amazon，知乎上有图片
In January 2015, the Wall Street Journal reported that WorldVu, now operating under the name OneWeb LTD, had secured funding fromVirgin Group and Qualcomm to build and launch the constellation, while SpaceX was not an investor and their role in the venture was not clear. OneWeb also divulged that the planned satellites will weigh approximately 125 kg (276 lb) and that plans are to deploy approximately 650 of them in low Earth orbit to operate at 1,200 kilometers (750 mi) altitude.
2014年-2015年，断断续续发声，2015更名为OneWeb，卫星数量650，实际为648
The OneWeb satellite constellation—formerly known as WorldVu—is a proposed satellite internet constellation of approximately 882 satellites expected to provide global Internet broadband service to individual consumers as early as 2019.
The 648 communication satellites will operate in circular low Earth orbit, at approximately 750 miles (1,200 km) altitude,[2] transmitting and receiving in the Ku band of the radio frequency spectrum.[1]
The satellites for the OneWeb constellation are reportedly 175–200 kg (386–441 lb) in mass.[12][18] The 648 operational satellites will operate in 18 polar orbit planes at 1,200 kilometres (750 mi) altitude.[18][29]
The satellites will operate in the Ku band, communicating in the microwave range of frequencies in the 12–18 GHz portion of the electromagnetic spectrum.[1][14] The satellites use a technique called “progressive pitch” in which the satellites are slightly turned to avoid interference with Ku-band satellites in geostationary orbit. The user terminal antenna on the ground will be a phased array antenna measuring approximately 36 by 16 centimeters (14.2 by 6.3 in) and will provide Internet access at 50 megabits/second.[14]
一网，882颗卫星，轨道高度1200km，极轨，18个轨道面，用户频率Ku波段，用户终端天线是相控阵，36x16cm，速率50Mbps。
不采用星间链路。
starlink
starlink, spaceX, Elon Musk
The communication satellite network SpaceX envisions was publicly announced in January 2015
2015年1月正式提出。
The Internet communication satellites are expected to be in the smallsat-class of 100-to-500 kg (220-to-1,100 lb)-mass, which are intended to be in Low Earth Orbit (LEO) at an altitude of approximately 1,100 kilometers (680 mi). Initial plans as of January 2015 were for the constellation to be made up of approximately 4000 cross-linked[30] satellites, more than twice as many operational satellites as were in orbit in January 2015.[5]
小卫星，100-500kg，LEO轨道，1100km，2500颗，有激光星间链路
The satellites will employ optical inter-satellite links and phased array beam forming and digital processing technologies in the Ku- and Kaband according to documents filed with the U.S. Federal Communications Commission (FCC).[35][36] While specifics of the phased array technologies have been disclosed as part of the frequency application, SpaceX enforced confidentiality regarding details of the optical inter-satellite links other than that they will utilize frequencies above 10,000 GHz.[37]
采用激光星间链路，对此保密
The system will not compete with Iridium satellite constellation, which is designed to link directly to handsets. Instead, it will be linked to flat user terminals the size of a pizza box, which will have phased array antennas and track the satellites. The terminals can be mounted anywhere, as long as they can see the sky.[30]
starlink不会和铱星竞争，铱星是手持终端，而starlink是大用户终端，大概披萨盒子大小，终端采用相控阵来跟踪卫星。
关于starlink的协议，链接
In response to a tweet musing what connection type SpaceX will utilise for Starlink, the tech entrepreneur explained that Starlink won’t utilise standard IPv6 connections. In fact, he states it “will be simpler than IPv6 and have tiny packet overhead.” It’s also “definitely” going to be a peer-to-peer connection.
Will be simpler than IPv6 and have tiny packet overhead. Definitely peer-to-peer.
— Elon Musk (@elonmusk) February 25, 2018
网络协议不会是IPv6，即IP-less，会是p2p协议。
A little after, in response to another tweet asking how he’d ensure this peer-to-peer connection would remain safe, Musk elaborated upon the technology he envisions for Starlink. On a base level, he sees it being “end-to-end encryption encoded at firmware level”. Musk believes such tech is “unlikely to be hacked [with] current computing tech” and, if it does end up being hacked, “a crypto fix will go out immediately via [a] network-wide firmware update.”
End-to-end encryption encoded at firmware level. Unlikely to be hacked w current computing tech. If it is (and we learn about it), a crypto fix will go out immediately via network-wide firmware update.
— Elon Musk (@elonmusk) February 25, 2018
端到端加密在固件层
One corner of Reddit is particularly interested in just how viable a non-IP-based internet system will work at such scale.
Reddit上有人想了解，如何不使用IP协议在组建这么大规模的网络。链接
Elon Musk announced SpaceX's multithousand satellite Internet service will be IP-less
Here's the thing.
I must say, I found it more than a little surprising that they are intending to implement a massive packet switching network without IP (at least internally). I suppose they could be planning to move traffic through a network of fixed connections, but this would seem to be suboptimal for the scenario we're talking about. Most SpaceX fans seem to be responding enthusiastically, but I'm curious what the more technical audience makes of this.
E: I slightly misspoke. I was surprised they want to forgo IP for something 'simpler', with smaller packets. As far as I can see, that only leaves link layer protocols. And, those aren't great for large LANs, let alone a global ISP. As I mentioned above, this could be done if they're just avoiding switch routing traffic between the satellites, but that doesn't sound every efficient.
Telesat，
https://www.telesat.com/services/leo/what-makes-it-great#video
User and gateway links @Ka-band
Optical crosslinks between satellites
Telesat’s LEO system uses optical inter-satellite links to directly connect locations anywhere on earth
Demodulation + modulation + IP-Routing（来源：http://www.mit.edu/~portillo/files/Comparison-LEO-IAC-2018-slides.pdf）
链接：https://pan.baidu.com/s/1_GhDcsUkYpHJ0KX_BaHruQ
提取码：fa2h
Low Latency
Typical round trip latency of 30-50 msec, more than 10 times faster than GEO satellites.