Broadband Types - DSL, Cable, BPL, Fiber, Cable, Wireless & Satellilte

What is Broadband

Dictionary Definition
The dictionary definition of broadband is: "of, pertaining to, or carrying a wide band of electromagnetic frequencies"

FCC Definition
The Federal Communication Commission declares broadband as any means of providing electronic communication at 200,000 bits per second or better. Most internet providers far exceed this metric though.

Notice that neither definition includes a means of providing electromagnetic frequencies, just that they are part of the definition.

Delivery Means
The problem is there are at least eight different ways to provide broadband. Some providers broadcast signals over the air (radio), others over wire (copper), and others still via light over a glass fiber (fiber-optic). The most common means was over copper wire, but this has changed a lot in the last few years with Wireless rapidly catching up with wired connections and fiber-optic finally coming into its own. Then there is the very real possibly that fiber-optic will surpass all of these other methods combined as the technology becomes cheaper and more widespread.

This article will discuss all these methods as well as their advantages and disadvantages.

Digital Subscriber Line Schematic (the DSL connection is represented by the blue line)
Digital Subscriber Line Schematic (the DSL connection is represented by the blue line) | Source

Digital Subscriber Line

Digital Subscriber Line works over standard telephone lines. It was originally an outgrowth of telcos converting their analog voice only lines to digital voice only lines.

The expense to convert in-plant (central office) voice to digital was massive, but once in place it was only a matter of time before telephone companies (telcos) figured out they could transmit pure data over those lines as well. Because the telcos had already spent a considerable sum on the equipment to convert analog voice signals to digital voice signals the additional expense of a DSL modem and the related service could be passed on to the customer at a profit.

The way a DSL system works is the digital voice signals are assigned to a particular frequency on the line and data only signals to its own higher frequency. To prevent the voice signal from interfering with the data signal a "low pass" filter was installed (now incorporated into the modem) to prevent the digital voice signals from interfering with the data only signals. This can be seen in the graphic at the upper right. All of this requires no change to the "twisted pair" wiring that services both the phone and the DSL modem at the users site.

Advantages
The customer does not need a dedicated line to send and receive digital data. The existing phone line, already installed in the home, is adequate for both voice and data transmission. This saved the telcos a considerable installation expense and made it easy for the customer to install the DSL modem.

Data transmission speeds were fairly high when the system was introduced with a common throughput (from end to end) speed in the eight (8Mbp/s) megabit per second range. As long as the connection was within one and a half miles of the Digital Subscriber Line Access Multiplexer (DSLAM) in the switching station, the customer could expect fast and reliable data transmission.

Over time the telcos improved both the DSLAM and DSL modems and extended the range from the switching station to the home to from three (3m) to six (6m) miles.

Disadvantages
As mentioned above the initial distance DSL could expected to work reliably was about three to six miles. This required telcos to install additional equipment along the line to boost the signal if distance demanded it. These amplifiers were called Loop Extenders. These extenders boosted the signal thereby extending the range to ten to twenty miles. Unfortunately, signal reliability drops off in a very consistent way with each mile added to the range. Loop extenders are an excellent means of enhancing signal strength in metropolitan areas.

This is not far enough to properly service rural areas and other means of getting the signal to the customer were embraced in 2006 with the Fiber to Home initiative.

The other problem with DSL is its upper speed limit; this limit drops of with distance. Currently the fastest connection speed offered by telcos is about six megabits (6Mbp/s) per second. Though this was considered quite fast as little as five years ago but, cable, fiber, and even Wi-Fi have surpassed this limit.

Despite the figures in the table below DSL (ADSL & SDSL) rates can be much higher than typically provided; the more common, lower speed figures are from AT&T.

See the table after the range table immediately below.

DSL Data Rates

DSL Data Rates
Upstream
Downstream
Top End
768 Kbps
6 Mbps
Mid Range
512 Kbps
3 Mbps
Low End
384 Kbps
1.5 Mbps
Budget
384 Kbps
768 Kbps
Higher Speeds are possible
 
 
M=Mega or million
 
 
K=Kilo or thousand
 
 
Upstream means from your computer to the network. Downstream means from the network (Internet?) to your computer.
Approved in
Version
Standard name
Common name
Downstream
Upstream
1998
ADSL
ANSI T1.413-1998 Issue 2
ADSL
8.0 Mbit/s
1.0 Mbit/s
1999-07
 
ITU G.992.1
ADSL (G.DMT)
12.0 Mbit/s
1.3 Mbit/s
2001
 
ITU G.992.1 Annex A
ADSL over POTS
12.0 Mbit/s
1.3 Mbit/s
2005
 
ITU G.992.1 Annex B
ADSL over ISDN
12.0 Mbit/s
1.8 Mbit/s
1999-07
 
ITU G.992.2
ADSL Lite (G.Lite)
1.5 Mbit/s
0.5 Mbit/s
2002-07
ADSL2
ITU G.992.3
ADSL2
12.0 Mbit/s
1.3 Mbit/s
 
 
ITU G.992.3 Annex J
ADSL2
12.0 Mbit/s
3.5 Mbit/s
 
 
ITU G.992.3 Annex L
RE-ADSL2
5.0 Mbit/s
0.8 Mbit/s
2002-07
 
ITU G.992.4
splitterless ADSL2
1.5 Mbit/s
0.5 Mbit/s
2003-05
ADSL2+
ITU G.992.5
ADSL2+
24.0 Mbit/s
1.3 Mbit/s
2008
ADSL2+
ITU G.992.5 Annex M
ADSL2+M
24.0 Mbit/s
3.3 Mbit/s
As with most other technologies DSL continues to improve.
Cable Schematic
Cable Schematic | Source

Cable Modem

Cable signals are basically radio waves confined to wire. Initially cable modems were confined to downstream (from the network to the user) only with the upstream (from the user to the network) signal typically sent on a separate wire, usually telephone.

This was an untenable situation to the cable companies and made them dependent on telcos, complicated the process of installing and maintaining the equipment, and caused a fair amount of customer dissatisfaction. Worse, it made data transmission over cable no better than DSL, the primary competing technology at the time.

In the late nineteen nineties, the cable companies set out to rectify the situation once and for all by creating the Data Over Cable Service Interface Specification (DOCSIS) standard.

This consortium has come up with three standards over the years with every increasing data transmission speeds.

DOCSIS 1.0 was able to support up to forty-two (42Mbp/s) megabits per second (maximum) downstream (to the computer from the network) and ten (10Mbp/s) megabits per second (maximum) upstream (from the computer user to the network.

DOCSIS 2.0 increased the upstream (from the computer user to the network) to thirty (30Mbp/s) megabits per second (maximum) without changing the downstream speed of DOCSIS 1.0.

DOCSIS 3.0 increased the downstream (from the network to the computer user) speed to fifty-five (55Mbp/s) megabits per second (maximum) without changing the upstream (from the computer user to the network) speed of DOCSIS 2.0.

Please note that these cable speeds are divided by four where the signal is split between a number of channels. This means that the overall DOCSIS speed of four channels combined could be as high as three hundred megabits per second (300Mbp/s).

If ADSL 2+ is compared to DOCSIS 3.0 they are roughly equivalent, but most consumers do not know which version of these protocols they are using.

Be sure to ask when checking on providers!

Advantages
If you already have a cable provider adding an Internet connection to that service could be as simple as a single quick visit by a technician to run additional coaxial cable and drop off the cable modem. This often takes an hour or less. Upgrading modems (and this is necessary over time to get the fastest available) is as simple as visiting your local cable company office ans swapping out modems.

Disadvantages
Cable modem is fast, but if anything happens at a distribution center, and this does happen from time to time, entire blocks of users (whole neighborhoods) can be blocked out at the same time.

Cable modem also tends to be more expensive than DSL even though ADSL 2+ is about as fast as cable modem.

Modems also sometimes have to be rest (unplugged and plugged back in) from time to time to get them re-synchronized with the cable provider.

Finally, cable providers play "fast and lose" with facts and figures often not being able to provide you with hard numbers to distinguish "good" from "better" to "best."

Click thumbnail to view full-size
Broadband over PowerlineBPL inside
Broadband over Powerline
Broadband over Powerline
BPL inside
BPL inside

Broadband over Powerline

This is exactly what it sounds like no matter how unlikely. Yes, it is possible to send data directly through the power in your walls. Yes, it requires special equipment, but some of it is quite cheap. In fact a very valid form of data connection with speeds between the low of Wi-Fi and the high of wired connection (DSL or Cable above) there lies data over power lines.

This is a relatively recent development, but it's getting a lot of study. After all, if data can be sent over power lines (and it can) almost everyone can have access to the Internet no matter where they live.

The Federal Communications Commission (FCC), as is often the case, was instrumental in promoting this means of connecting to the Internet. The FCC formerly adopted rules to help vendors begin deploying BPL to homes and business in 2004. The rules are loosely referred to as "Access BPL."

In an attempt to spur this on the FCC took the unusual step of crafting looser than normal rules for implementing BPL; however, the provisions require BPL providers to investigate and correct any interference they may cause.There have been concerns by aviation, business, commercial and amateur radio that sending data over power lines could interfere with broadcast radio signals.

FCC chief Kevin Martin has said that Broadband over Powerline "holds great promise as a ubiquitous broadband solution that would offer a viable alternative to cable, digital subscriber line, fiber, and wireless broadband solutions. Mr Martin also said that BPL was one of the FCCs "top priorities".

Advantages
If you have electrical power coming into your home you already have an available data connection in your walls. A BPL modem connects directly through the wall socket with an Ethernet cable running to your computer.

Disadvantages
This is such a new service and is so experimental that most areas of the country do not have it nor is it available.

Data over Fiber-Optic
Data over Fiber-Optic | Source

Data over Fiber-Optic

This technology was developed in the 1970s, but was not widely distributed until the early 1990s when cheaper signal processors and smaller gallium arsenide lasers were created.The first optical fiber was created by Corning Glass Works in 1970.

Basically the way this works is data is sent to a converter which takes the electrical signal that makes up the data transmission and converts it to light. The light is then sent down an optical fiber (glass) up to one hundred twenty-four miles until it reaches its destination. The light then enters another converter where the light is converted back into an electrical signal.

Commercial Applications
Telcos were the first to recognize the viability of this method when General Telephone and Electronics sent live telephone signals through fiber-optic cable in Long Beach, California. This system operated at approximately forty-five (45Mbp/s) megabits per second. Signals traveling over ten kilometers required a signal repeater to re-strengthen the signal.

The second development in fiber-optic data transmission involved improved lasers and an "simple-mode" glass fiber which was designed transmit a single laser beam of a very specific wave-length of light. This system was capable of transmitting up to one point seven (1.7Gbp/s) giga (billion) bits per second. This system required signal repeaters spaced at fifty kilometer intervals.

The third development in fiber optic data transmission improved, yet again, on the glass fiber and the laser semiconductors that were used. The biggest improvement in this third generation of data transmission by light was to craft the light fiber in such a way that it did not allow light dispersion within the cable. These systems could transmit data at up to two point five (1.5Gbp/s) gigabits per second and with repeaters spaced every 100 kilometers.

Up to now increasing the light being pumped through the fiber required that the light be converted back to an electrical signal, amplified, converted back to light, and passed yet again into the glass fiber. Also, connectors were a constant source of trouble with a well designed, cheap, and reliable "light connector" being a major challenge for a while. Cheap was the key problem here.

By the year 1992 it became practical to send multiple wave-lengths of light down a single cable (wavelength division multiplexing) thereby increasing the capacity of fiber-optic cable at least two fold. Additionally optical amplifiers were developed that directly boosted the light signal without first converting it to an electrical signal to amplify it only to convert that signal back to light to send it on its way again. These two improvements gave optical fiber data transmission speeds up to ten terabits (trillion) for up to one hundred sixty kilometers without amplification.

Though fiber to home is currently still a new idea, fiber to business is quite popular. This condition could change in the very near future as at least a million homes now have fiber to premises. With improvements in technology, providing cheaper, faster, and more reliable data transmission via fiber-optics is inevitable.

Advantages
Very very fast. Not even radio broadcast is as fast as data over fiber-optic cable. Better the range is quite far now, which makes supporting the signal standard that much cheaper for providers. Because fiber-optic is not subject to electromagnetic interference a lot less filtering is required which in turn cuts down on the amount of equipment required to drive a fiber network. Well trained technicians also provide an important element; the better trained the technician the cleaner the signal regardless of how far it has to go. Finally, advances in fiber are being made on an almost daily basis. Terabyte signal to the home could be available in a few short years.

Disadvantages
Despite all of the amazing advances fiber-optic still requires the provider to actually run the cable to where it will be used. Unlike cable, telco, and wireless, the expense to have to run new cable to a new installation can still be cost prohibitive especially when compared to the cost of systems already established. Still, companies are going this way because the advantages of fiber far outweigh the expense of laying it.

Wi-Fi Logo
Wi-Fi Logo | Source

Wireless

In this instance we are talking about Wi-Fi and derivatives such as Long Term Evolution (LTE) and Wi-Max.

Wireless is quite popular right now primarily because it is one of the foundations of smartphone technology, but also because many home users are finding that adding Wi-Fi in the home can allow them to use a desktop computer in one room and a laptop, notebook, netbook, or tablet in another room with only one Internet connection.

Wi-Fi is nothing more than a radio signal designed to transmit data. The original specification for Wi-Fi was proposed by the Institute of Electrical and Electronics Engineers. It is operated at a very high frequency and for that reason its range is typically limited to a few score square feet such as a few rooms in a home or the customer area of a cafe or coffee house.

Wi-Fi enabled devices include personal computers (netbooks, notebooks, laptops, and tablets), video game consoles, smartphones, and even digital audio players. The Wi-Fi connection typically interfaces the computer with the Internet, but Wi-Fi can also be used to connect personal computers to local and company networks.

Though 'Wi-Fi' is not a technical term the moniker is used with any wireless system using the IEEE 802.11standards. At this point in time Wi-Fi is used by seven hundred million people around the world in at least seven hundred fifty thousand locations.

Advantages
Wi-Fi is one of the few means of accessing the internet that requires no cabling or even a great deal of technical knowledge on the part of the user. For the most part a person with a Wi-Fi enable devices is automatically connected once they are in range of a "hotspot" or at worst may have to make a few menu selections or hit a few hot keys to make a connection.

Disadvantages
Wi-Fi has severely limited range. The signal can also be affected by the placement of furniture in the room, the location of the base station to the personal computer, or even the location of walls and windows within the location using it. It is also slower than wired connections, though this may change in the immediate future.

Communications Satellite Orbits (blue geosynchronous / green low earth orbit)
Communications Satellite Orbits (blue geosynchronous / green low earth orbit) | Source

Satellite

Voice over satellite started in 1962 with two satellites dedicated to telephone communications. These were collectively called TELSTAR. The satellites were used to establish voice service over the Atlantic Ocean with cooperation between Bell Telephone Labs, NASA, the British Post Office, and French National PTT (Post, Telephone & Telegraph Office).

In 1962 Telstar was also used, briefly, to broadcast television signals. In 1963 Syncom3 was launched strictly as a television signal satellite and was later followed by Intelsat (1965) which was the first commercial television satellite venture.

In the early 1990s a concerted effort was made to broadcast television directly to the home from satellite with Dish Network.  This was followed by DirectTV in 1996.

Data over Satellite
In the 1990s satellite was seriously considered as a means of providing Internet connectivity and such services began being provided to users in remote locations.

Advantages
Satellite Internet is nearly uninterrupted with only occasional breaks in service caused by weather or the even more rare solar storm. It is perhaps the best means of providing connectivity in truly remote locations. Additionally, satellite Internet is virtually immune to natural disasters such as earthquake, hurricanes, tornadoes and the like.

Disadvantages
One of two types of orbits need to be attained for effective communications. One is the geosynchronous satellites which must be 35,000 miles above the surface of the earth. This means that, even at the speed of light, there will be noticeable delays between upstream requests and downstream responses.

The other type of orbit is the low earth orbit which largely eliminates the time delay, but requires a constellation of satellites to support communications. Since each satellite is within line of site of the user for only about four to fifteen minutes. This means that a much more sophisticated means of synchronizing signals between satellites must be maintained. This in turn makes the service cost prohibitive (to the end user) for all but the most extreme situations.

Wrapping Up

As of now the absolute best broadband connections are via fiber-optic to home. Unfortunately, this option is still largely unavailable to most of the population in the United States. This is starting to change and rapidly, mostly in urban areas.

The second best are shared by Cable and DSL services. The drawback here is that DSL service has stagnated (though the technology itself has continued to improve) where cable keeps moving forward.

Wi-Fi should only be considered if speed is not that important and mobility is the primary consideration.

Broadband over Powerline is still in its infancy.

Satellite, as that section states, is a last resort connection for those in very remote areas.

Interestingly almost all of the technologies above user fiber-optic somewhere in their makeup. This includes wireless communication. Industry has used fiber-optic for decades as the backbone of signal transmission, even if you can't see it directly.

Disclaimer

The author was not compensated in any way, monetarily, with discounts, or freebies by any of the companies mentioned.

Though the author does make a small profit for the word count of this article none of that comes directly from the manufacturers mentioned. The author also stands to make a small profit from advertising attached to this article.

The author has no control over either the advertising or the contents of those ads.

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Comments 2 comments

mywriteup 5 years ago

nice..almost a wiki page of Broadband!


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Puppyluv 5 years ago from Hanover, PA

Wow! Excellent information! I'm beyond impressed. Very useful for those of us that don't have all the information necessary to make a decision. Thank you! Voted up and rated useful.

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