Filling The Broadband Gap

By John Dunbar and Chris-Spencer Smith, Myacom LTD.

Every country that is aspiring to deliver “broadband”

ADSL services has the problem that significant numbers

of the population (typically 20% to 60%) live in areas that

are not yet ADSL enabled. Getting worldwide coverage up to

say 95% will take years as the Telcos face the law of diminishing

returns. Meanwhile, ISDN is an ideal gap-filler product assuming

the Network Termination (NT) and/or TA has the right characteristics.

Figure 1 - The Broadband Gap

What is the Broadband Gap?

The Broadband Gap, illustrated in Figure 1, represents the percentage of the population

who live beyond the reach of Broadband.

Why is there a Broadband Gap?

The main cause of the Broadband Gap is that not all exchanges are Broadband enabled.

This is directly linked to population density and Telco investment. Initially, Broadband

(ADSL) was targeted at areas of high population density in order to get the ‘best bang for the buck’.

As the penetration is focussed towards more rural areas the population density decreases so the

cost per customer passed increases and the ROI falls.

In these days of competitive telecommunications Telcos cannot afford the costly luxury of providing

ADSL to everyone (‘universal service’), so the Broadband Gap is here to stay.

Even allowing for the gradual targeting of exchanges for conversion, based on demand,

it will remain between 15% and 20% of the population.

Why does the Broadband Gap have to be Filled?

This promotion of broadband generates an enormous customer demand, which can only

be met for ~70-80% of the country. This leaves a large proportion of the population unsatisfied,

and disappointing almost one in four customers when they ask for Broadband is not ideal.

Filling the Broadband Gap with a ‘Broadband Lite’ product avoids this disappointment, and

will demonstrate to customers that their operator does have ‘Internet-age’ solutions for all.

What can be done about the Broadband Gap?

There are several possible ways to fill the Broadband Gap, such as innovative financing arrangements,

use of Satellites for Broadband data, or alternatives such as ISDN.

Innovative Financing

In the UK there have been sponsorship trials for ADSL in rural areas, with development agencies,

government or local companies targeted as sponsors. Whilst this will definitely succeed in

some instances it will not be a general solution to the Broadband Gap.

Broadband Satellite

Broadband Satellite data transmission has the advantage of passing 100% of all homes.

There are two basic flavours: bi-directional satellite links, and one-way satellites which use a

standard phone line for the return link. Of the two the one-way satellite is the most common.

Although the use of Satellite for filling the Broadband gap is expensive, prices are beginning to drop.

Because of the distances travelled by the satellite signals there is a noticeable delay on transmission

of data (typically 250 to 500ms) on each leg. In fact, typical Internet browsing can be slower on

Satellite links than on ISDN, and is not suitable at all for Internet gamers. Satellite links come

into their own when large quantities of data have to be transferred but are not a practical alternative

for the normal Internet user.

Cable Modem

The Cable companies are tied as much as the incumbent telcos on ROI, and, for example in the UK,

their coverage (40%) is lower than that covered by ADSL. Where Cable sometimes can act as

a Gap filler is on the few long reach telephone lines in densely populated areas, but even here

Rate Adaptive ADSL is closing this gap.

ISDN “Midband”

ISDN is a half-way house between modems and ADSL for Internet Access,

sharing many of the potential benefits of ADSL, although not being able to match it on

headline speed

	Modem	ISDN “Midband”	ADSL
Time to Connect	45 secs	Always on with AODI 2-3 seconds for dial-up	Always on
Uplink Throughput	40kbps 80kbps with compression	125kbps 250kbps with compression	250kbps
Downlink Throughput	40kbps 80kbps with compression	125kbps 250kbps with compression	500kbps
Simultaneous Phone and data	No	Yes	Yes

Table 1: Comparison of ADSL, ISDN and Modem Characteristics

The above table illustrates the positioning of an ISDN-based ‘Broadband Lite’

solution to fill the Broadband Gap. Whilst the full download speeds of ADSL

cannot be matched, ISDN is a still a substantial step forward for modem users,

with near instantaneous connections, three times modem speeds and the ability to ‘talk and surf’.

If AODI is supported in the Operator’s network then, with a suitable NT, ISDN matches

another feature of ADSL: an always-on connection. This enables users to have a permanent

web presence for services ranging from home monitoring/home automation, to hosting web pages.

For ISDN to be a successful Broadband Gap filler the solution must have certain characteristics so

that it doesn’t become a hurdle for ADSL deployment in the future.

These are summarized in the table below:

Characteristics of an Ideal ISDN Broadband Gap Filler

· ADSL-ready	-	Enables the the user to plug his terminal into the phone socket without having to have an engineer visit to uninstall the ISDN equipment.
· User Installable	-	Reduces cost of Deployment as there is no need to send an engineer to install the network terminal
· PSTN port(s)	-	The solution needs to be able to offer PSTN service, using Q.931 or NMDS
· AODI	-	AO/DI provides the optimal use of ISDN infrastructure for providing always-on Internet access, only using B-channels when surfing.
· Dynamic 128k	-	Only uses 2 B-channels when they are both needed, e.g. during a big download which reduces infrastructure requirements/costs and also network congestion
· Channel Dropping	-	Enables the user (or household members) to make phone calls even when surfing at 128k.
· Available today	-	The need for a Broadband Gap filler is today!

Table 2 – Characteristics of an Ideal Broadband Gap Filler

The Broadband Gap Filled ….. by ISDN

· ISDN passes 98% of all homes

· ISDN improves the Internet experience with near instantaneous time to connect, and 3 times the speed of a modem.

· ‘Sweats the assets’ by re-using exiting exchange and network infrastructure.

· Saves copper by getting voice and data down a single line.

· Example: In the UK this solution is being promoted by BT as “BT Midband”.

For more information please contact:

Dr. John Dunbar Chris Spencer-Smith

Managing Director Head of Product Management

john.dunbar@myacom.com chris.spencer-smith@myacom.com

+44 1444 883101 +44 1444 883103