Error correcting codes for extremely high error rates

On Thu, 16 Jan 2014 05:32:35 -0800, julius wrote:

> On Wednesday, January 15, 2014 10:55:16 PM UTC-5, dvsarwate wrote:
> 
>> Time to revive an old post of mine
>> 
>> But Eric's point about comm specsmanship brings to mind an apocryphal
>> story about how IBM won a contract for a military comm. system.  Both
>> the IBM design and Brand X had the same data rate and same BER but the
>> IBM design used a rate 1/2 code while the competing design used a rate
>> 2/3 code.  Anyway, IBM won because they told the generals "In our
>> system, we use one parity bit to protect each data bit, whereas in the
>> Brand X system each parity bit has to protect *two* data bits and so
>> their system provides only half as much data protection as ours does."
> 
> We have systems that operate at seconds-per-bit, and there are stories
> of competitors who manage to convince potential clients that larger
> seconds-per-bit numbers are better.

Well, it certainly gives you more time to savor the information that does 
come through!

-- 
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

On Thursday, January 16, 2014 11:15:50 AM UTC-5, Tim Wescott wrote:
> 
> 
> Well, it certainly gives you more time to savor the information that does 
> come through!
> 

I have no formal proof of this, but today we probably charge the most per bit delivered! 

On Thursday, January 16, 2014 11:45:26 AM UTC-5, julius wrote:
> On Thursday, January 16, 2014 11:15:50 AM UTC-5, Tim Wescott wrote:
> 
> > 
> 
> > 
> 
> > Well, it certainly gives you more time to savor the information that does 
> 
> > come through!
> 
> > 
> 
> 
> 
> I have no formal proof of this, but today we probably charge the most per bit delivered!

Do you give refunds on the errored bits? lol! Interplanetary space probes along with the deep space network have a high cost per bit too. Not sure how it compares with your case.

julius <juliusk@gmail.com> wrote:
> On Thursday, January 16, 2014 11:15:50 AM UTC-5, Tim Wescott wrote:

(snip)

>> Well, it certainly gives you more time to savor the information 
>> that does come through!
 
> I have no formal proof of this, but today we probably charge 
> the most per bit delivered! 

In an optics class some years ago, I was told about the system
for communicating with submarines using a 7Hz carrier. 

More specifically (and maybe not exactly 7Hz) the EM resonance
frequency of the earth. 

Also, another submarine communication system at about 15kHz where
the index of refraction of water is about 9.

-- glen

On Thursday, January 16, 2014 1:13:20 PM UTC-5, glen herrmannsfeldt wrote:
> julius <juliusk@gmail.com> wrote:
> 
> > On Thursday, January 16, 2014 11:15:50 AM UTC-5, Tim Wescott wrote:
> 
> 
> 
> (snip)
> 
> 
> 
> >> Well, it certainly gives you more time to savor the information 
> 
> >> that does come through!
> 
>  
> 
> > I have no formal proof of this, but today we probably charge 
> 
> > the most per bit delivered! 
> 
> 
> 
> In an optics class some years ago, I was told about the system
> 
> for communicating with submarines using a 7Hz carrier. 
> 
> 
> 
> More specifically (and maybe not exactly 7Hz) the EM resonance
> 
> frequency of the earth. 
> 
> 
> 
> Also, another submarine communication system at about 15kHz where
> 
> the index of refraction of water is about 9.
> 
> 
> 
> -- glen

Schumann resonances


Clay

On Thursday, January 16, 2014 12:54:37 PM UTC-5, cl...@claysturner.com wrote:
> 
> Do you give refunds on the errored bits? lol! Interplanetary space probes along with the deep space network have a high cost per bit too. Not sure how it compares with your case.

We don't sell the bitrate in and by itself, we sell the ability to send commands downhole to your drilling system. Not sure on the details since I'm not a field guy but I'm pretty sure there is a tolerance limit (have to be able to send xxxx percent of commands successfully).

On Thursday, January 16, 2014 1:13:20 PM UTC-5, glen herrmannsfeldt wrote:
> 
> In an optics class some years ago, I was told about the system
> for communicating with submarines using a 7Hz carrier. 
> 
> More specifically (and maybe not exactly 7Hz) the EM resonance
> frequency of the earth. 
> 
> Also, another submarine communication system at about 15kHz where
> the index of refraction of water is about 9.
> 

Stay calm and don't panic, but we use <1 Hz carrier, and sometimes carrierless with bandwidth <0.1 Hz. It all depends on the signal generator and the propagation channel. 

I laugh at the notion of ELF (Extremely Low Frequency) which is at 3-30 Hz according to Wikipedia. 

I suggest today we launch two new terms: RLF (Ridiculously Low Frequency) for anything 0.125-12 Hz carrier. And ULF (Unbelievably Low Frequency) for symbol rates less than 0.1 symb/sec. 

On Thursday, January 16, 2014 10:45:26 AM UTC-6, julius wrote:

> 
> I have no formal proof of this, but today we probably charge the most per bit delivered!

Reminds me of the old saw (perhaps no longer true)
that the fastest way to send a terabyte of data from
New York to Los Angeles is to ship a hard drive by
Federal Express!  Might even have been the least charge
per bit delivered.

On Thursday, January 16, 2014 12:36:29 PM UTC-7, dvsarwate wrote:
> On Thursday, January 16, 2014 10:45:26 AM UTC-6, julius wrote: > > I have no formal proof of this, but today we probably charge the most per bit delivered! Reminds me of the old saw (perhaps no longer true) that the fastest way to send a terabyte of data from New York to Los Angeles is to ship a hard drive by Federal Express! Might even have been the least charge per bit delivered.

http://what-if.xkcd.com/31/

On Thursday, January 16, 2014 2:36:29 PM UTC-5, dvsarwate wrote:

> Reminds me of the old saw (perhaps no longer true)
> that the fastest way to send a terabyte of data from
> New York to Los Angeles is to ship a hard drive by
> Federal Express!  Might even have been the least charge
> per bit delivered.

For drilling, the fastest fully-commercial way to communicate is to "fish" the electronic core off a tool and dump the onboard memory. 

For wireline we get Mbps easily.