A year ago italians drove robot cars from Beograd to Shanghai. In small russian city, policeman tried yo issue ticket to driver-less car, while they were preparing for some show in the main city square.
Ticket was not issued: maybe policeman was impressed by several italians talking to him (in italian, not russian), or he just could not find how to fill up the forms...
Nice article about the trip: VIAC: An Out of Ordinary Experiment - Computer Engineering Group www.ce.unipr.it/people/bertozzi/pap/cr/iv2011.pdf
First we fixed phone: after some research with Android (not really Linux) we ended up with 5 year old bluetooth car installation: the only one where you can make calls without any keys, just sound.
Computer is next: some tests were made using joystick (manipulated by head movement) installed on wheelchair. Not really fun. There are some expensive monitors with build in infrared cameras tracking eye movement.
Any experience on Linux desktop? Any advice what works?
Yes, GSM system needs to know the cell you are using during a call. This seems to be known issue: How come phone exchange knows with whom I am talking? It seems a bit silly to me, really. If cell is not known, connection can not be established.
On top of it: GSM is TDMA system, so it measures distance to the terminal in cca 550m steps. It is called Timing Advance, it is needed in order to allign all incomming frames on cell receiver.
Now... Somebody looks at Abis (protocol between cell and Base Station Controller). You can see measurement reports: with a cell, distance, measurement reports you can guess approximate terminal location during a call. If you have enough neighbour cells.
They overlooked two minor details: - you do not know whom you locate - you have to monitor all possible cells In fact, you have to double complete operator infrastructure: not an easy task.
On top of it: more and more GSM (BSS) is using IP as transport between cell and system, especially if collocated with HSPA+ or LTE. IPsec is used on this interfaces.
Even operators, who need this data during system tuning and debugging, have problems to get it. Special test SIM cards, protocol probes after SGW etc are used. Normally, such tests are prepred and executed on selected cells: getting all data history for all users is beyond reach of most operators.
It is much easier to get my location using different methods, like asking me politely;-)
Doing this On the same frequency is remarkable. but the gains they are claiming can be had right now by using TWO frequencies. Transmit on channel 1 receive on channel 12.. t
This might be problem if you want mesh network with many (n>2) nodes. They (mostly) want to hear each other.
Anyhow, with 100 dB (10 000 000 000) times stronger transmit signal I somehow doubt if geometry of antennas can be accurate enough to keep it working with changing temperature, humidity etc. over MHz of bandwith. Maybe with heavy DSP processing and continuos monitoring? Compensating for scattering of own signal, and all reflections from surounding objects?
On top of it, we normally use MIMO: so you have to do it on 4 receiving antennas;-). Even with MIMO 2by2 we might double channel capacity in perfect (MIMO perfect) radio conditions.
Yes, it is possible in the lab. But mass products?
Ah, back to good old Shannon: just double the bandwith.
Assuming we have 5 THz of usable bandwith (limited by todays fiber and optical amplifiers), and applying some technology known from radio for quite some time:
Advanced modulation (1024 QAM): 10 bits/sec Polarization diversity (or mimo 2*2) by 2
So, 100 Tbit/sec is approximate reasonable limit for one fiber. There is some minor work to transfer technology from experimental labs to the field, but this is just matter of time.
Wavelength mupltiplexing just make things a bit simpler: Instead of one pair of A/D converters doing 100 Tbit/sec, we might use 1000 of them doing 100 Gbit/sec.
In 2010, speed above 60 Tbit/sec was already demonstrated in the lab.
Eh, will we say soon: "Life is too short to surf using 1 Gbit/sec"?
In a year or two, most GSM/W-CDMA networks will be upgraded to WB-AMR codecs. Orange is already using it in Moldova and London, others are testing. It is marketed as High Definition Voice.
WB-AMR uses 16 kHz sampling instead of classic 8 kHz . Together with better voice compression, higher quality of voice is using same capacity (say, 12.2 kbit/sec) as we use today. Of course, PCM is out. Both sides of connection must support WB-AMR, and everything in between as well, so for few years it might not be available across different networks. If one terminal can not use it any more (maybe due to handover to GSM cell not supporting WB-AMR), fallback to AMR/EFR is made on both sides, using 64k/56k PCM inbetween.
Technology is avaialble for quite same time, but terminal vendors are slowing it down. Some 20% of all terminals have to support it, otherwise it makes no sense for operator to buy all SW needed to implement it network wide.
Funny: good old GSM will soon get higher voice quality as ISDN.
I heard this one: Telekom installers were bringing fiber to the house in the mountain. Old man asked them: what are you doing? And they answered by telling about internet. And then he said: Nice, but I would prefer if you bring power lines as well.
Last few years, most cellular operators are rolling out IP to the base stations. For HSPA/LTE speeds, E1/T1 PDH/ATM is out of the question, and as IP is rolled out, GSM gets there as well.
Accurate timing is essential: even transmitter frequency is synchronized over IP, and keeping 2 GHz accurate to 100 Hz is not simple. Local oscillator can do it short term, but external correction is needed as well.
Beside GPS (used in IS-95), several systems are used. IEEE 1588v2 is obvious one. Works.
Some vendors do it with modified NTP: generate a lot of requests, and do some statistic processing. Thus, most of the jitter can be compensated, and accuracy can be kept. Normally, it works over intranets, with NTP having high priority, but it is used over internet as well (femto and pico base stations).
Real life tests indicate it works, just do not put it over ADSL;-)
- E-ink has perfect size, it fits big pocket (and it is really readable) - good to read in the bed or on the beach - most of my reference library for the job is there (in html) - open (I could add my own SW or fix it, if needed), with SW updates flowing - battery life: it takes 10 days between charging, and device is never switched off - it is dedicated device and does the job - perfect match if I could link it with 3G phone via USB. - on meetings, I take notes on the paper
I am monitoring progress, and I plan to buy new E-reader, but - bigger screens are vulnerable (we are waiting for plastics instead of glass) - all added functionality increases power consumption and size - if I need 3g, wifi, divx: another device - I watch movies on TV with beer and remote: can not do it on PC - if I want laptop, I use laptop.
So, no new device impressed me enough to get one. I expect one to two years: new technology with bending screen could make a difference. So far, it is nothing new: just incremental progress. Nothing worth going for.
On the other hand, it is niche product. Biggest shop in Ljubljana reported to sell only 100 devices in the year. (lack of slovenian E-books).
I am in this particular niche: While SW become user friendly, I am still machine friendly. (Aged over 50, learned FORTRAN in 1974).
Don't be silly. Secret ballot is one of the cornerstones of democracy.
In a secret ballot, you don't get bribed to vote for a particular person because you can always say you voted for him while voting for him.
That is exactly why mobiles with camera are not allowed while voting. When bribed, you have to show a picture how you voted, or send MMS, to provide proof of your voting.
While it is possible to make your vote invalid afterwards, for most people this is quite effective.
First we have GSM: made for voice, pefect for voice.
Then HSPA come. And VoIP over HSPA: HSPA is not good enough. So HSPA+ is tried, not good enough for voice. So we need LTE to deliver voice over IP for IMS in order to have what GSM already provides.
Slashdot Mirror
When I took some time to become fammiliar with Mandarin, main goals were:
1. By understanding their grammar I am much better in understanding them speaking English.
2. Using few sentencies helps break some barriers when meeting Chinese.
3. It is fun to learn something new.
Now... A bit later all three goals are OK, it is first time I tried to learn non-indoeuropean language,
and point 3 definitily justifies time spend.
73
s62d
When I saw "book source", latex was expected.
(As I am incompetent artist, I seek latex book sources to take something consistent for my projects)
No, it is done in ASCIIDOC - yet another book making program.
While TeX and LaTeX are old, they are still excellent tools for the job.
What makes alternatives better? What can not be done properly by TeX?
BR
s52d
A year ago italians drove robot cars from Beograd to Shanghai.
In small russian city, policeman tried yo issue ticket to driver-less car,
while they were preparing for some show in the main city square.
Ticket was not issued: maybe policeman was impressed by several italians talking to him (in italian, not russian),
or he just could not find how to fill up the forms...
Nice article about the trip:
VIAC: An Out of Ordinary Experiment - Computer Engineering Group
www.ce.unipr.it/people/bertozzi/pap/cr/iv2011.pdf
Ciao,
Iztok
It happened to my friend. No hands, no legs.
First we fixed phone: after some research with Android (not really Linux) we ended up
with 5 year old bluetooth car installation: the only one where you can make calls without
any keys, just sound.
Computer is next: some tests were made using joystick (manipulated by head movement)
installed on wheelchair. Not really fun.
There are some expensive monitors with build in infrared cameras tracking eye movement.
Any experience on Linux desktop? Any advice what works?
Thanks,
s52d
It is much easier to get my location using different methods, like asking me politely ;-)
BR
s52d
Can you, please, tell us where you currently are, preferably within 550m accuracy?
At home, 1m from my PC.
And you have my home address from elsewhere, of course.
BR
s52d
Yes, GSM system needs to know the cell you are using during a call.
This seems to be known issue: How come phone exchange knows with whom I am talking?
It seems a bit silly to me, really. If cell is not known, connection can not be established.
On top of it: GSM is TDMA system, so it measures distance to the terminal in cca 550m steps.
It is called Timing Advance, it is needed in order to allign all incomming frames on cell receiver.
Now... Somebody looks at Abis (protocol between cell and Base Station Controller).
You can see measurement reports: with a cell, distance, measurement reports you can guess
approximate terminal location during a call. If you have enough neighbour cells.
They overlooked two minor details:
- you do not know whom you locate
- you have to monitor all possible cells
In fact, you have to double complete operator infrastructure: not an easy task.
On top of it: more and more GSM (BSS) is using IP as transport between cell and system,
especially if collocated with HSPA+ or LTE. IPsec is used on this interfaces.
Even operators, who need this data during system tuning and debugging, have problems to get it.
Special test SIM cards, protocol probes after SGW etc are used. Normally, such tests are prepred
and executed on selected cells: getting all data history for all users is beyond reach of most operators.
It is much easier to get my location using different methods, like asking me politely ;-)
BR
s52d
Doing this On the same frequency is remarkable. but the gains they are claiming can be had right now by using TWO frequencies. Transmit on channel 1 receive on channel 12.. t
This might be problem if you want mesh network with many (n>2) nodes. They (mostly) want to hear each other.
Anyhow, with 100 dB (10 000 000 000) times stronger transmit signal I somehow doubt if geometry of antennas can be accurate
enough to keep it working with changing temperature, humidity etc. over MHz of bandwith.
Maybe with heavy DSP processing and continuos monitoring?
Compensating for scattering of own signal, and all reflections from surounding objects?
On top of it, we normally use MIMO: so you have to do it on 4 receiving antennas ;-).
Even with MIMO 2by2 we might double channel capacity in perfect (MIMO perfect) radio conditions.
Yes, it is possible in the lab. But mass products?
Ah, back to good old Shannon: just double the bandwith.
73
Iztok
Assuming we have 5 THz of usable bandwith (limited by todays fiber and optical amplifiers),
and applying some technology known from radio for quite some time:
Advanced modulation (1024 QAM): 10 bits/sec
Polarization diversity (or mimo 2*2) by 2
So, 100 Tbit/sec is approximate reasonable limit for one fiber.
There is some minor work to transfer technology from experimental labs to the field,
but this is just matter of time.
Wavelength mupltiplexing just make things a bit simpler:
Instead of one pair of A/D converters doing 100 Tbit/sec, we might use 1000 of them doing 100 Gbit/sec.
In 2010, speed above 60 Tbit/sec was already demonstrated in the lab.
Eh, will we say soon: "Life is too short to surf using 1 Gbit/sec"?
Hi!
In a year or two, most GSM/W-CDMA networks will be upgraded to WB-AMR codecs.
Orange is already using it in Moldova and London, others are testing.
It is marketed as High Definition Voice.
WB-AMR uses 16 kHz sampling instead of classic 8 kHz . Together with better voice compression,
higher quality of voice is using same capacity (say, 12.2 kbit/sec) as we use today.
Of course, PCM is out.
Both sides of connection must support WB-AMR, and everything in between as well,
so for few years it might not be available across different networks.
If one terminal can not use it any more (maybe due to handover to GSM cell not supporting WB-AMR),
fallback to AMR/EFR is made on both sides, using 64k/56k PCM inbetween.
Technology is avaialble for quite same time, but terminal vendors are slowing it down.
Some 20% of all terminals have to support it, otherwise it makes no sense for operator
to buy all SW needed to implement it network wide.
Funny: good old GSM will soon get higher voice quality as ISDN.
73
Yes, it is available in Bled.
I heard this one:
Telekom installers were bringing fiber to the house in the mountain.
Old man asked them: what are you doing? And they answered by telling about internet.
And then he said: Nice, but I would prefer if you bring power lines as well.
BR
Iztok
Just have to notice:
> Yes, it is kinda weird to see Slovenia top the US....
FTTH. Two companies (T-2 and Telekom) are rolling it heavily, we are 8th world-wide in FTTH penetration.
DOCSIS 3.0. It is hard to see TV antennas: some 70% of people are on the cable networks or watch TV/IP.
Whoever is still on ADSL is considered "poor".
But, some 10% of population has no access to broadband.
73 from Ljubljana
Iztok
Hi!
Last few years, most cellular operators are rolling out IP to the base stations.
For HSPA/LTE speeds, E1/T1 PDH/ATM is out of the question,
and as IP is rolled out, GSM gets there as well.
Accurate timing is essential: even transmitter frequency is synchronized over IP,
and keeping 2 GHz accurate to 100 Hz is not simple.
Local oscillator can do it short term, but external correction is needed as well.
Beside GPS (used in IS-95), several systems are used.
IEEE 1588v2 is obvious one. Works.
Some vendors do it with modified NTP: generate a lot of requests, and do some statistic processing.
Thus, most of the jitter can be compensated, and accuracy can be kept.
Normally, it works over intranets, with NTP having high priority, but it is used over internet as well
(femto and pico base stations).
Real life tests indicate it works, just do not put it over ADSL ;-)
73
Iztok
It is almost two years I am in love with my E-reader.
http://wiki.mobileread.com/wiki/Hanlin_V3
- E-ink has perfect size, it fits big pocket (and it is really readable)
- good to read in the bed or on the beach
- most of my reference library for the job is there (in html)
- open (I could add my own SW or fix it, if needed), with SW updates flowing
- battery life: it takes 10 days between charging, and device is never switched off
- it is dedicated device and does the job
- perfect match if I could link it with 3G phone via USB.
- on meetings, I take notes on the paper
I am monitoring progress, and I plan to buy new E-reader, but
- bigger screens are vulnerable (we are waiting for plastics instead of glass)
- all added functionality increases power consumption and size
- if I need 3g, wifi, divx: another device
- I watch movies on TV with beer and remote: can not do it on PC
- if I want laptop, I use laptop.
So, no new device impressed me enough to get one.
I expect one to two years: new technology with bending screen could make a difference.
So far, it is nothing new: just incremental progress. Nothing worth going for.
On the other hand, it is niche product. Biggest shop in Ljubljana reported to sell only 100 devices in the year.
(lack of slovenian E-books).
I am in this particular niche:
While SW become user friendly, I am still machine friendly. (Aged over 50, learned FORTRAN in 1974).
73
Iztok
Don't be silly.
Secret ballot is one of the cornerstones of democracy.
In a secret ballot, you don't get bribed to vote for a particular person because you can
always say you voted for him while voting for him.
That is exactly why mobiles with camera are not allowed while voting.
When bribed, you have to show a picture how you voted, or send MMS, to provide proof of your voting.
While it is possible to make your vote invalid afterwards, for most people this is quite effective.
First we have GSM: made for voice, pefect for voice.
Then HSPA come. And VoIP over HSPA: HSPA is not good enough. So HSPA+ is tried, not good enough for voice.
So we need LTE to deliver voice over IP for IMS in order to have what GSM already provides.
Noone is using WIndows to do some real job.
If we assume average teenager has 100 Euros per month to spend ...
20 years ago, they mainly spend it on music, beer and cigarettes.
Today they spend it on mobile, internet, DVDs, computer games and some for music.
There are so many options beside CDs.
Music industry simply lost entertainment money share.
Few years ago a pool was made in London: kids prefer to stop going out for beer in order to spend last pounds on their mobile phone.
It is so nice, when 2 Mbit/second is actually 2*1024*1000 bit/second.