Starlink sent and received texts over a 4G/LTE connection between mobile phones via its latest generation of satellites, called v2mini, for the first time this month, following similar projects from Amazon, Apple, AST SpaceMobile, Huawei, and Lynk Global. Starlink—the satellite constellation operated by SpaceX—will offer text messaging to subscribers of at least eight different mobile-network operators around the world and may offer voice and data coverage without the need for the ground terminals its customers now use in “coming years,” Starlink’s U.S. partner T-Mobile said in a statement.

Starlink 本月首次透過其最新一代衛星 v2mini 透過手機之間的 4G/LTE 連接發送和接收文本，亞馬遜、蘋果、AST SpaceMobile、華為和 Lynk Global 也推出了類似項目。 Starlink——由 SpaceX 運營的衛星星座——將向全球至少八個不同行動網路營運商的用戶提供簡訊服務，並可能提供語音和數據覆蓋，而無需客戶現在使用的地面終端。」Starlink 的美國合作夥伴T-Mobile 在聲明中表示。

The Starlink achievement is the latest example of how satellites and cellular base stations are converging. A handful of companies are exploiting cheaper satellite fabrication and launch costs, as well as adapting existing technologies such as beamforming, to bridge the several hundred kilometers between mobile phones and orbiting satellites. Among the many new wrinkles those companies have to iron out is the fact that for the first time, the towers themselves are the mobile component of the network: Low Earth orbit (LEO) satellites move at tens of thousands of kilometers an hour, so they have little time to communicate with any one mobile phone on the Earth’s surface.

星鏈成就是衛星和蜂窩基地台融合的最新例子。少數公司正在利用更便宜的衛星製造和發射成本，並採用波束成形等現有技術，以架起手機和軌道衛星之間數百公里的橋樑。這些公司必須解決的許多新問題之一是，塔本身首次成為網路的移動組件：低地球軌道（LEO）衛星以每小時數萬公里的速度移動，因此它們幾乎沒有時間與地球表面的任何一部手機進行通訊。

The companies competing to solve these problems have so far sent and received text messages on conventional phones via a commercial satellite (Huawei/China Telecom; Lynk Global; Apple/Globalstar) and performed voice and data calls over 5G via an experimental satellite (AST SpaceMobile) as IEEE Spectrumhas reported. Investors have taken notice: Lynk Global is going public in a deal that values the company at up to US $800 million while AT&T, Google, and Vodafone recently invested in AST SpaceMobile, which has a market capitalization of $674.6 million.

迄今為止，競相解決這些問題的公司已透過商業衛星（華為/中國電信；Lynk Global；蘋果/Globalstar）在傳統手機上發送和接收短信，並透過實驗衛星（AST SpaceMobile）透過 5G 進行語音和數據通話）正如IEEE Spectrum 所報導的。投資者已經注意到：Lynk Global 即將上市，該公司估值高達 8 億美元，而 AT&T、Google 和沃達豐最近投資了 AST SpaceMobile，後者的市值為 6.746 億美元。

“I recall many discussions 10 years ago where the mobile operators told the satellite people, ‘Your price points are way too high.’ This has totally changed due to more availability of the technology, more agile development, and a different approach to failure.”—ANDREAS KNOPP, UNIVERSITY OF THE BUNDESWEHR

「我記得10 年前的許多討論，行動營運商告訴衛星人員，『你們的價格點太高了。』由於技術的可用性更高、開發更敏捷以及失敗的處理方法不同，這種情況已經完全改變。 」——安德烈亞斯·克諾普，德國聯邦國防軍大學

Until very recently, satellites could not connect to mobile phones hundreds of kilometers below. The sort of satellite phones people took on expeditions to more remote places have chunky antennas, require clear lines of sight to multiple satellites, and take a while to acquire a signal. Integrating terrestrial and satellite cellular networks isn’t as easy as moving between cell towers and handing off the signal from one to the next.

直到最近，衛星還無法連接到數百公里以下的手機。人們去更偏遠的地方探險時使用的衛星電話有粗大的天線，需要與多顆衛星保持清晰的視線，並且需要一段時間才能獲取訊號。整合地面和衛星蜂窩網路並不像在蜂窩塔之間移動並將訊號從一個蜂窩塔傳遞到另一個蜂窩塔那麼容易。

Indeed, the task is so difficult that one research group built an experimental application to help an Internet-connected livestock truck equipped with its own computer switch to an onboard Starlink ground station when the truck loses the cellular network signal. Achieving a seamless integration of terrestrial and nonterrestrial networks is the ultimate goal, says study coauthor Melisa López, a wireless communications researcher at the University of Aalborg in Denmark.

事實上，這項任務非常困難，以至於一個研究小組開發了一個實驗應用程序，幫助一輛配備自己的電腦的連網牲畜卡車在失去蜂窩網路訊號時切換到車載星鏈地面站。研究合著者、丹麥奧爾堡大學無線通訊研究員 Melisa López 表示，最終目標是實現地面和非地面網路的無縫整合。

Starlink doesn’t explain many details of its 4G connection, but existing commercial constellations reveal several of the building blocks of seamless satellite cellular connections, and researchers have published at least one promising lead for future constellations.

Starlink 沒有解釋其 4G 連接的許多細節，但現有的商業星座揭示了無縫衛星蜂窩連接的幾個構建模組，研究人員已經發布了至少一個未來星座的有希望的線索。

Three Keys to Connecting Phones to Satellites

Instead of redesigning mobile phones to be more like satellite phones, companies are redesigning the satellite network to meet mobile phones more than halfway. They are making the antennas on the satellites much bigger in their scramble to turn satellites into cellphone towers. For example, AST SpaceMobile’s first satellites had antennas with surface areas of 64 square meters, followed by second generation satellites with 128 m2 antennas, with plans for going up to 400 m2. Starlink’s new v2mini satellite antennas are 6.21 m2, but Starlink plans even larger cellular-compatible satellites that it will launch when its larger Starship rocket is available.

將手機連接到衛星的三家關鍵公司不再將手機重新設計得更像衛星電話，而是重新設計衛星網絡，以適應手機的一半以上。他們正在將衛星上的天線做得更大，以期將衛星變成手機訊號塔。例如，AST SpaceMobile 的第一顆衛星的天線表面積為 64 平方米，隨後的第二代衛星天線面積為 128 平方米，計畫擴大到 400 平方米。 Starlink 的新型 v2mini 衛星天線面積為 6.21 平方米，但 Starlink 計劃推出更大的蜂窩兼容衛星，當其更大的 Starship 火箭可用時，將發射這些衛星。

Companies are also making their satellites more like cellphone towers by flying them lower than before. For the first few decades of the space age, communications satellites were inserted into geosynchronous orbits much higher above the Earth, where they could cover a large portion of the planet’s surface for a relatively long period of time. However, those satellites handled far fewer devices than exist today.

公司還透過將衛星飛行得比以前更低，使衛星變得更像手機發射塔。在太空時代的最初幾十年裡，通訊衛星被插入比地球高得多的地球同步軌道，在那裡它們可以在相對較長的時間內覆蓋地球表面的大部分地區。然而，這些衛星處理的設備比現在少得多。

The advent of smaller and cheaper satellites and cheaper launch costs in the last decade or so have enabled business models that rely on many cheaper satellites flown in low Earth orbit. These new satellites won’t last as long but will be better able to detect the weak signals from mobile phones on the surface and handle their growing traffic.

過去十年左右，更小、更便宜的衛星的出現以及更便宜的發射成本使得依賴許多在近地軌道上飛行的更便宜的衛星的商業模式成為可能。這些新衛星的使用壽命不會那麼長，但能夠更好地偵測地面手機發出的微弱訊號並處理日益增長的流量。

SpaceX’s Starlink network can connect directly to an off-the-shelf cellphone, potentially eliminating the need for bulky satellite phones.STARLINK

SpaceX 的 Starlink 網路可以直接連接到現成的手機，從而可能消除對笨重衛星電話的需求。STARLINK

“I recall many discussions 10 years ago where the mobile operators told the satellite people, ‘Your price points are way too high.’ This has totally changed due to more availability of the technology, more agile development, and a different approach to failure,” says Andreas Knopp, a signal processing engineer at the University of the Bundeswehr in Munich.

「我記得10 年前的許多討論，行動營運商告訴衛星人員，『你們的價格太高了。』由於技術的可用性更高、開發更敏捷以及失敗的處理方法不同，這種情況已經完全改變了， 」慕尼黑聯邦國防軍大學信號處理工程師 Andreas Knopp 說。

Another contributor is improved beamforming, which is how a transmitting device calculates the best way to direct its signal to reach a particular recipient, without interfering with other recipients. That may involve bouncing a signal off a building or mountainside, from terrestrial towers, or it may involve precise targeting of a narrow, fast-moving signal, from a satellite moving tens of thousands of kilometers per hour.

另一個貢獻者是改進的波束成形，這是發射設備如何計算將其訊號引導至特定接收者而不干擾其他接收者的最佳方式的方式。這可能涉及從建築物或山坡、地面塔反射訊號，或者可能涉及從每小時數萬公里移動的衛星精確瞄準狹窄、快速移動的訊號。

More sophisticated beamforming can involve sending the same signals from multiple antennas so that the signal’s reinforce each other, a bit like when sound waves harmonize. Anyone who has tuned a home speaker system to provide the best sound at the point of a particular couch has done beamforming, probably with the help of sophisticated software in the background.

更複雜的波束成形可能涉及從多個天線發送相同的訊號，以便訊號相互增強，有點像聲波協調一樣。任何將家庭揚聲器系統調整為在特定沙發上提供最佳聲音的人都已經完成了波束成形，可能是在後台複雜軟體的幫助下進行的。

In the future, it may be worth spreading the task of beamforming across even more satellites than now, write the authors of a pair of recent papers. A scenario floated in one of the studies is the use of more than two dozen tiny satellites flying in close formation to replicate the work done today by one cellular-compatible satellite. “Each of these satellites is now independent, with its own components. The main aspect is this synchronization algorithm, which has to align frequency, phase, and the time for the signals to arrive coherently,” says Diego Tuzi, a graduate student studying signal processing at the University of the Bundeswehr who, together with Knopp, is a coauthor on one of those recent papers.

最近兩篇論文的作者寫道，未來，可能值得將波束成形任務分散到比現在更多的衛星。其中一項研究中提出的一個場景是，使用兩打以上緊密編隊飛行的微型衛星來複製目前由一顆蜂巢相容衛星所做的工作。 「這些衛星現在都是獨立的，有自己的組件。主要方面是這種同步演算法，它必須調整頻率、相位和訊號一致到達的時間，」德國聯邦國防軍大學研究訊號處理的研究生迭戈·圖齊(Diego Tuzi) 說道，他與克諾普(Knopp)一起，最近發表的其中一篇論文的合著者。

For now, what Starlink and its competitors are offering is very little, though it is a necessary step. “It’s better than nothing,” says Thomas Delamotte, another coauthor on the recent paper and a signal processing engineer at the University of the Bundeswehr, “but if you want to have a long-term perspective we will need new approaches to make 6G ubiquitous.”

目前，星鍊及其競爭對手提供的服務非常少，儘管這是必要的一步。 「這總比沒有好，」最近論文的另一位合著者、德國聯邦國防軍大學的信號處理工程師托馬斯·德拉莫特(Thomas Delamotte) 說道，「但如果你想擁有長遠的眼光，我們將需要新的方法來讓6G 無處不在。 」。