Saturday, May 8, 2010

DSL, Cable, Satellite, Or 4G - Comparison For Broadband Internet Service and HDTV

Telephone, Internet, and TV service are now routinely bundled by service providers. It is convenient to have a single supplier and one bill a month. With the availability of VoIP (Voice over Internet Protocol), the lines between the different services have blurred further.

Broadband Internet service (High Speed) for residential or small business requirements has usually been available from two sources: DSL, a system that piggybacked on the telephone wiring from the telephone company, or Cable, a system that similarly piggybacked on the cable TV wiring. In 2008, about 25 million customers utilized cable broadband, and about 22 million customers utilized DSL. In 2001, a total of about 5 million customers used either cable broadband or DSL.

For most people the TV coaxial cable has offered better performance than DSL, but if you were highly price conscious, then the DSL cable may have been competitive. So, in a discussion of broadband choices, we should include cable and DSL, but we will also discuss new options that are now available like WildBlue satellite, and services that will soon be available like WiMax (WiFi with a city-wide hot-spot) and ViaSat (satellite communications on steroids).

The Impact of Video Downloads (especially HDTV):

Despite the relatively small number of users, research indicates that systems such as BitTorrent and YouTube account for more than half of all Internet traffic. In 1995 the total amount of data transacted over the Internet backbone was about 1.5 million GB. By 2006, this had grown to over 700 million GB.

ABI Research projects that the number of video downloads to increase from 215 million downloads this year (2008) to 2.4 billion downloads in 2012. This number becomes more impressive when one takes into account that a much higher per cent of those downloads in 2012 will be HDTV files, which are much larger (A non HDTV movie is approximately 3 GB/Hour, HDTV file size is dependent on encoding: an MPEG-4 encoded HDTV movie file size is approximately 5 GB/Hour, an unencoded 1280 X 720 movie file size is over 150 GB/Hour, and an unencoded 1920 X 1080 movie file size is over 350 GB/Hour).

By 2010, forecasts call for 80-90% of Internet traffic to be video transfer.

Cable and the Phone Companies (DSL):

Cable broadband is capable of about 30 MBPS of bandwidth, however, speed can vary. Unfortunately, the measurement in real-world conditions can be more complicated. If many people in your neighborhood use the same broadband service as you, and those people use a lot of bandwidth, for video downloads for example, then you will be sharing some resources, and your performance will suffer. Most service providers offer service with between 3-6 MBPS bandwidth for downloads. Upload bandwidth is lower: usually between 200-600 KBPS.

Median DSL speed in the U.S. is 768 KBPS. One type of DSL technology, VDSL, is capable of 30 MBPS bandwidth, but this service is not widely available. Instead, telephone companies more commonly offer ADSL or SDSL services (cheaper and slower).

Both Cable Broadband and DSL service providers commonly employ bandwidth caps for residential and small business customers. Service providers concerned about the overall capability of their network may institute the capacity constraints so that they can provide equal performance to all of their customers.

Cable and the Phone Companies HDTV:

Verizon is building fiber-optic networks that will be capable of broadcasting handle 200+ HDTV channels in addition to all of the conventional TV channels.

Most cable operators have enough available bandwidth for only about 10-12 HDTV channels without a major retooling of their networks.

WiMax and LTE:

In major metropolitan areas in the U.S., WiMax should available late in 2008. Sprint will make its commercial WiMAX debut in Baltimore in September. WiMax supports peak data speeds of about 20 MBPS, but, as with most broadband technologies, that bandwidth will be shared amongst users. On average, a user will see data rates between 1 MBPS and 4 MBPS.

Most major wireless carriers are skipping WiMax, planning instead to build out networks using a similar technology called Long Term Evolution (LTE), a successor to current cellular technology. WiMax has a head start on LTE, which won't be ready until 2010. These two technologies are referred to as 4G networks (Current state of the art mobile phone technology for accessing the Internet is called 3G). If mobile broadband service is important to you, these products will be very attractive. Unlike rivals GSM and CDMA, both 4G networks are based on "Orthogonal Frequency Division Multiplexing" (OFDM), also sometimes referred to as "discrete multi-tone modulation". Since both LTE and WiMax are based on similar technology, a unified standard is possible in theory, and discussions are ongoing. Motorola has said 85% of the technology and work for WiMax equipment will be reused in its designs for LTE equipment.

WiMAX and LTE can deliver large amounts of bandwidth operating at the low power levels necessary for mobile devices. Another advantage of WiMax/LTE is its ability to communicate out of line-of-sight (unlike conventional WiFi), and to communicate into large buildings, in theory making dropped calls, typical of today's cell phones, a thing of the past. A company called MobiTV will utilize the WiMAX network for the broadcast of TV, including HDTV. VoIP (telephone service) has already been deployed on WiMAX networks in other parts of the world.

Satellite Broadband:

Also newly introduced into the Broadband market, is WildBlue Satellite. This broadband service does not require a phone or cable line. WildBlue Satellite broadband service offers download/upload speeds starting at just $50 per month (512 kbps download speed with upload speed up to 128 kbps), or $80 per month (1.5 Mbps download speed and uploads up to 256 kbps). For those living in areas not well served by Cable Broadband and DSL, this is an attractive alternative. iNetVu offers a portable system for vehicles.

A very powerful new satellite, Viasat-1, will launch in 2011. This satellite will greatly improve the competitiveness of satellite in this field. ViaSat-1 has a total throughput capability of over 100 Gb/second, which is more capacity than the current American fleet of two-way C, Ka, and Ku band satellites combined. In 2010, a similar service will be launed in Europe by Ka-Sat.

Both WildBlue and ViaSat terminals use a networking technology that uses satellite bandwidth more efficiently, called DOCSIS (Data Over Cable Service Interface Specifications), lowering the cost of Internet service to consumers. The terminals include satellite modems and Ka band transceivers. DOCSIS has the ability to address "rain fade", a reduction in signal that is caused by heavy cloud cover, like during a thunderstorm. DOCSIS automatically responds to a reduced signal caused by atmospheric conditions with variable power control and data encoding techniques.

ViaSat-1 will offer more than a 10X increase in the capacity with frequency reuse by utilizing a technique called "SpotBeams" (WildBlue also uses SpotBeams). The high throughout of ViaSat-1 makes it ideal for transmitting new video applications requiring ultra high bit rates such as HDTV, HD digital cinema, and 3D TV. Spotbeams can be compared to a searchlight. SpotBeams focus a signal on an area 100 to 200 miles across. Thge same frequencies can be be reused many time, but for a different focus area.

WildBlue and ViaSat are geosynchronous satellites. A geosynchronous satellite remains above the same spot on the earth by orbiting at approximately 36,000 kilometers above the equator. Your signal must do a round-trip, and the minimum time for such a trip is about 1/4 second.

Satellite HDTV:

While HDTV local channels are more available on cable than satellite, DirecTV and the Dish Network each offer more national HDTV channels. DirecTV offers about 60 national HDTV channels and the Dish Network has about 50 HDTV channels. DirecTV and EchoStar plan additional satellites to offer at least 150 national HD channels, as well as local stations in HDTV.

"Satellite's going to be constrained not so much by how many channels they can carry than by how many they can get," Bob Scherman, Satellite Business News.

By 2010, it is projected that 60% of TV receivers will use a Satellite signal, up from 15% in 2002.

Median DSL speed in the U.S. is 768 KBPS.
Median Internet speed over Cable broadband is about 4.5 MBPS.
WildBlue service is approximately 500 KBPS.
WiMax service will be between 1 MBPS and 4 MBPS.
ViaSat-1 service (2011) will be about 2 MBPS.

HDTV service is currently more fully served by the satellite TV companies like DirectV and Dish Network. New systems being implemented by Verizon, or perhaps a thorough retooling by local cable TV operators will offer the best competition.

The supply of HDTV and Broadband service in the U.S. is currently fragmented from the satellite industry. Both may be available from local retailers, but a unified system is lacking. This compares poorly to Europe and EutelSat, which will launch Ka-Sat in 2010 (Ka-Sat is very similar to ViaSat-1, discussed above), and install this satellite in a satellite "neighborhood", so that a single system will receive both the TV signals from their HotBird satellite system, and receive high performance broadband from Ka-Sat. This is unfortunate for U.S. consumers.

Currently, over 90% of customers of broadband services utilize either cable broadband or DSL. However, new worthy competition is entering the fray, and it will be difficult for those services to maintain their market share.

About the Author: Brian Bradshaw is a Certified Technical Specialist (InfoComm CTS). Areas of expertise include Video, Audio, Computation, HDTV, Satellite Systems, and Communications. He has a communications technology business in Plano, Texas (Dallas). More information can be found at his Website:

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