Contributions to ETSI-TM6, related to ADSL, VDSL and Spectral Management
Over a period of 13 years (1996-2009), I have been active in ETSI-TM6, a European standardisation body on DSL technology.
In that period, I made >250 technical contributions to this body for creating the European requirements in standards on HDSL, SDSL, ADSL and VDSL, as well as the creation of Spectral Management standards.
From 1999-2009, I have been acting as the Rapporteur for ETSI to chair the creation
of both parts of the European Spectral Management standards ETSI TR 101 830.
The aim was to offer technical solutions for Local Loop Unbundling (and Subloop Unbundling), so that competative operators can make use of the same access network.
Such unbundling requires rules for preventing a disproportional interference between incompatible DSL modems.
SpM Part 1 offers a technology-independent method for specifying what signals are alowed for injecting into their network.
SpM Part 2 offers a calculation method for designing spectral management rules in a particular access network.
Below an overview of all these contributions, grouped according to topic:
The documents below changed the way DSL performance is currently measured in test setups. In the early days of ISDN and HDSL,
it was common to test modems with white noise, at levels that independent on the loop length. This was far from realistic.
Today, all DSL standards that followed (ADSL, SDSL, VDSL) specify mandatory performance tests, using frequency dependent
noise, that changes in shape and level with the loop length. This is how crosstalk noise behaves in an operational environment
with multiple DSL systems in the same cable.
This improved methodology was introduced in 1997 for VDSL (see 974t20a0), and gradually accepted
within and outside ETSI for SDSL and ADSL as well (see 980p10xx).
Predicting DSL performance, for design and spectral management
The documents below had a significant impact on the way DSL performance is currently predicted under operational
It started with the creation of realistic cable models up to 30 MHz, and to collect that
information for European cables in a common document (see 970p02r3). Testloop #2 of
the ETSI VDSL standard is based on cable model "TP150", which represents a Dutch cable (introduced in 971t15r1).
Lateron the focus was concentrated on the creation of the current ETSI Spectral Management standard (part 2).
This was a mix of consensus building on PSD templates for DSL modems ("transmitter models"), development of receiver models, and
on the way crosstalk has to be estimated in a loop. Most of the content of that standard is based on the contributions below.
European regulations forced incumbent operators to unbundle their twisted pair networks. It means that multiple (competitive) operators
can use the copper wires to offer broadband services via DSL equipment. This included the concept of line sharing, where equipment from
one operator (POTS or ISDN) shares a wire pair with equipment from another operator (xDSL). Networks, processes and standards were never
prepared for this, and a way has to developped to prevent that one modem disturbes many others in a disproportional manner.
The solution was to bound the signal levels of equipment via legal contracts, a so called "access rule" which is mandatory for granting access.
But these rules were to be well specified in a meaningfull and technically-correct way. This resulted in the start of creating "part 1" of the
Spectral Management standard.
The documents below have created most of this standard.
Creation of Spectral Management Part 1 (ETSI TR 101 830-1) - for specifying national access rules
The creation of "Spectral Management, part 1" started in 1999, and provides a library of (informative) signal descriptions.
It is a great help for authorities who would like to use "access rules" as mandatory requirment for granting access to a
twisted-pair access network. These authorities can be an incumbent operator acting as loop provider, a industry forum of
licensed operators, or a national Regulator.
If the list of available "signal description" contains signal limits that are adequate for the job, such an authority can simply refer to it
(or copy the text)
This standard has grown to its current size via multiple steps. It has been constructed within the standardisation body ETSI-TM6,
by Rob F.M van den Brink acting as Rapporteur/Editor. A so called "living list" document contains the proposals, and a so called "draft"
contains what text has achieved consensus. ETSI published various versions of this draft as standard (TR 101 830-1),
as soon as sufficient content was added and agreed. The documents below show the history of that process.