How Hollywood's Hedy Helped Heighten Handhelds

szczys writes: Hedy Lamarr is a household name for the wrong reason. Her name is known as a Hollywood actress, but her legacy is in your pocket and reaches far more people than her movies. She was a brilliant thinker who plied her skills during World War II, developing technology that could help to win the war. Her patent wasn't used at the time, but is a foundation of spread-spectrum which is used in the radio modules of your cellphone: WiFi, Bluetooth, GPS, and others. This frequency hopping concept sat unused for decades before being added to the most ubiquitous of wireless connectivity methods.

Thank you, Hedy.

[fustakrakich]

No, it's Hedley!

Re:

[ClickOnThis]

No, it's Hedley!

From TFA, it's Hedwig Eva Maria Kiesler.

The true history can be found here

[Skewray]

The true history can be found here: http://destroyhistory.com/ [destroyhistory.com] .

Re:

[olsmeister]

+1 Blazing Saddles reference!

Re:Thank you, Hedy.

[R3d M3rcury]

(For those who don't get it.) [youtube.com]

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[khelms]

'scuse me while I whip this out!

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[Rassleholic]

No, it's Headcrab!

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[ClickOnThis]

I think it was encumbered not by the fact that it was patented, but (per TFA) by the fact that it was classified.

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[fustakrakich]

Exactly [wikipedia.org], (though that came after the war)... And some things, like truly effective encryption (if it exists at all) is born secret [wikipedia.org]

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[Gr8Apes]

You know - none of that matters if you publish prior to getting informed what you just published is "classified". Oops, cat is out of the bag, barn, and farm.... Kind of like Phil....

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[amiga3D]

They developed the system for the war effort originally. Thus the secret classification.

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[Gr8Apes]

I'm aware of what they did and why. What my statement was is that if you, as an individual, publish something like Phil Zimmerman did with PGP (which was subject to these types of laws) then you have effectively neutralized these types of laws if that is your intent. Some will say this is bad, or even illegal. Phil was subjected to some intense scrutiny and an investigation, but ultimately was effectively "just" harassed as no legal action was taken. Much like DVD Jon, or any of the others were attempted to

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[amiga3D]

That seems to about cover it.

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[Deadstick]

The patent expired in 1958.

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[ChrisMaple]

Many applications of frequency-hopping spread spectrum require complexity that isn't practical with vacuum tubes. Commercial applications needed to wait for integrated circuits.

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[dbIII]

Not really since the patent was based on a working prototype. Commercial applications had to wait for desperation driving a search for a solution to potentially congested airwaves. See also the current "cable tv" appliances that have IPv6 addresses only due to a rollout larger than the remaining unallocated continuous IPv4 address space.

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[publiclurker]

If I recall, the prototypes involved mechanical devices that were kept in sync with clockwork. Useful for shorter time periods like controlling a torpedo, but not all that useful for something needing long term stability.

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[dbIII]

I'm not sure what your point is since the patent dates to less than ten years before solid state transistors were commercially available.

Agh

[American AC in Paris]

Asinine Alliteration Accentuates Author's Atrociously Antiquated Awareness About Awesome And Able Actress

Re:

[Big Hairy Ian]

Surely she's famous for suing Mel Brooks over the Blazing Saddles

This is a great article!

[Anonymous Coward]

But how can we encourage more women and minorities to join STEM fields? We're discouraging future Hedy Lamarrs with the toxic 'bro culture' that pervades programming.

Re: This is a great article!

[Anonymous Coward]

Target Hollywood stars, obviously.

Re:

[fustakrakich]

And famous chefs [cia.gov]

Nonsense

[Anonymous Coward]

This frequency hopping concept sat unused for decades before being added to the most ubiquitous of wireless connectivity methods.

Frequency hopping has been used by the military long before cell phones were invented.

Hedy Lamarr helped win the Cold War.

Horrible!

[Tablizer]

Heavy "H" Heaping Hinders Helpful Headlines. Have Heart!

spread spectrum and player pianos

[binarstu]

The invention was quite interesting, too -- a mechanical implementation of spread spectrum that was based on player piano technology [harvard.edu].

Pure hype

[kamapuaa]

It's a great story, but her invention was never used. It's really a huge stretch it really relates at all to current spread-spectrum technology. Even if you think it is related, spread-spectrum as developed did not base their ideas on her invention, and it's unlikely they were even aware of it.

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[tlhIngan]

It's a great story, but her invention was never used. It's really a huge stretch it really relates at all to current spread-spectrum technology. Even if you think it is related, spread-spectrum as developed did not base their ideas on her invention, and it's unlikely they were even aware of it.

Depends.

Hedy Lamarr's spread spectrum, called Frequency Hopping Spread Spectrum (FHSS) is used in Bluetooth and early WiFi (802.11, no "b") is the first known implementation. Basically, Hedy based it on a piano roll u

Frequency Hopping vs Direct Sequence

[Phil Karn]

I don't mean to denigrate her contribution in any way, but Lamarr's frequency-hopping spread spectrum is not the one used in CDMA mobile phones. It is used in Bluetooth.

Lamarr invented "frequency hopping" while CDMA cellular and GPS use "direct sequence". Frequency hopping is just what it sounds like: a narrowband transmitter is continually retuned to a different radio channel. Unless the receiver tuning follows the same sequence at the proper times it cannot receive the transmission.

Direct sequence XORs a narrowband signal with a high speed pseudorandom "chip" sequence, and the receiver undoes this operation by XORing it again by the same sequence properly synchronized in time. It closely resembles a keystream-type encryption system, though the "keystream" is not necessarily secret. The main difference is that direct sequence is a wideband signal while, at any instant, a frequency hopped signal is still narrowband.

Each method has advantages. Frequency hopping can be especially resistant to strong narrowband jamming, so it's a favorite of military systems (Lamarr's intended use). Direct sequence is easier to use with coherent modulation so it tends to use transmitter power more efficiently, and it can often provide precise timing and positioning as a side benefit. Or, in the case of GPS, as its primary purpose.

While CDMA mobile phones were very important in the 1990s and 2000s, it is now being replaced with LTE (Long Term Evolution), which uses OFDM - Orthogonal Frequency Division Multiplexing. So do many other modern terrestrial digital communication systems including DSL, HD Radio, DVB-T (but not ATSC), WiFi and DRM (Digital Radio Mondiale).

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[Brett Buck]

Thank you! Every time this comes up, I end up writing a rebuttal along the same lines.

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[MountainLogic]

As the above AC notes, the Lemar patent really seemed to be aimed at a slightly different type of application than current cell phones. Besides it being a frequency hopper and not direct sequence, the intent of the frequency hopping was intended to evade detection while modern cells phone use spread spectrum for better bandwidth utilization.

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[Darinbob]

This story comes up a lot. I always assumed it was common knowledge amongst engineers. But not as many engineers on slashdot anymore.

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[gl4ss]

this seems to come up on tech sites yearly. how very forgotten..

Compare and contrast

[PopeRatzo]

Here is a photo of Hedy Lamarr. Naked.

https://jnpickens.files.wordpr... [wordpress.com]

Here is a photo of Phil Zimmerman. Fully clothed.

http://cdn.androidbeat.com/wp-... [androidbeat.com]

Now who wants to argue that there shouldn't be more women in tech?

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[Anonymous Coward]

Hard to believe more women don't choose STEM careers, when they could work with guys like you.

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[GrahamCox]

Don't you mean: Alliterations are awfully asinine?

Who?

[dohzer]

Who is Hedy?

Interning at TheRegister.co.uk lately?

[rainer_d]

At least, it looks like that

Re:

[cant_get_a_good_nick]

Also, it was classified for a few years during and after the war.

So... she's known for being an actress, a very public field, more than she's known for something that she was sworn to secrecy for,. This is a problem, or even a surprise, why?

Now for the Reddit deluge

[cant_get_a_good_nick]

Now we'll see two or three times the volume of this tidbit on Reddit /r/todayILearned.