Overcoming high-rise fibre issues
Carsten Storbeck, director of product management with ADC KRONE, tells us how running fibre can be as easy as running copper cable!
Fibre-to-the-home (FTTH) is going to happen. In some countries it is well advanced with customers enjoying data speeds of 100Mb/sec into their homes. In other countries, carriers are trying to squeeze the last couple of years out of their aging copper networks, but the best they can achieve is around 50Mbit/sec, which is not going to satisfy consumer demand in the future.
Running fibre to every home is not difficult – but the process of digging-in fibre is expensive. One area that is proving especially difficult is once the wireman actually gets inside the building.
In America where, in some regions, FTTH (fibre-to-the-home) quite prevalent, over 70% of the housing stock is single detached dwellings that are not a big problem.
However, in Europe, over 70% of the population live in flats, apartments, terraces or town-houses, collectively referred to as MDUs or Multi-dwelling units. These are far more difficult to fibre-up.
Traditionally, cabling up such a building for telephony was easy. Either a multi-pair ‘dropwire’ or underground cable was terminated onto a DP (distribution point) and two or three pair cable run to each dwelling or, in larger buildings, the incoming cable went to a DP (probably in the basement) then a multi-pair riser to a DP on each floor and finally small cables to each dwelling.
In new buildings, the cables would be concealed in risers and conduits or trunking and in older buildings they would be carefully run up staircases and around skirting boards, through doorframes, etc.
Today it is necessary to deliver 50 or 100 Mb/sec, perhaps 1Gb/sec, to each dwelling. Category 5e/6 cable can only run 9m from the active electronics that terminates the external fibre connection. Plus, this has the disadvantage that Telco electronics has to be housed in the basement and fed with electric power – probably with battery standby UPS too.
A better alternative is to take fibre right into every dwelling in the MDU – but, this has always been a difficult and costly process.
Currently, the building has first to be surveyed; all fibre routes worked out and measured with extreme accuracy. The survey has to be passed back to the office and into the purchasing system. A ‘special order’ has to be placed on a fibre cable manufacturer and special-to-length cables produced.
Some three or four weeks may pass before the cables come into stores and the job can be allocated to a site technician.
Alternatively, the site technician can carefully run in the fibre cable risers from basement to each floor where fibre distribution points are placed then smaller fibre cables from these fibre DPs to each dwelling.
However, care must be taken as everyday fibre cables do not tolerate the rough treatment that copper cables can be subjected to, nor will they tolerate right-angle bends or being stapled to skirting boards and the like. So fibre cables do not fit well with the technicians’ current on-site working methods.
Either a skilled fibre-splicing technician has to do the whole job or, once the cable-laying is all done, one has to be called on to splice all the fibres at the basement DP, per-floor DP and each customer’s dwelling. Often this can mean that 100 or more splices are needed. Every splice also has to be tested.
So until now, fibering-up a multi-dwelling unit has been an expensive business. Until the recent launch of fully-modular plug-and-play MDU fibering system by ADC KRONE.
The new breed of MDU fibre system includes fibre cable developed out of military experience that can be stapled to skirting boards and architraves without damage, bent round every type of right angle found in buildings (and on average every horizontal run needs to go around 15 right-angles) it can even be run over repeatedly by a Chieftain Tank without either damage or degradation of signal!
The real piece-de-resistance though are fibre distribution points (called fibre distribution hub and fibre distribution terminals) that have a hidden, in-built fibre cable-reel, pre-loaded with a pre-terminated 30, 60 or 90m fibre cable to run back to the previous DP.
In fact there are only four components and even with the different fibre-length variants only nine component. This means that with a stock of these nine variants in his van the wireman can simply turn up and start work. There is no need for a site-survey and no need for a four-week wait while special-to-type fibres are manufactured.
In this new scenario a fibre distribution hub (FDH) is wall-mounted in the basement or near the external fibre cable entry point. This can come complete with an external fibre-cable stub to run out to the external fibre splice enclosure or can optionally have splice-trays for termination of the external fibre. From then on it is totally plug and play.
On each floor, a fibre distribution terminal is mounted on the wall. Behind the active fibre-connection box is a fibre cable reel pre-loaded with up to 200m of 12- or 24-fibre cable with an MT-type multi-fibre connector.
The wireman simply pays-off enough cable and feeds it back to the FDH in the basement. (On larger jobs possibly via a fibre collector unit on a higher floor.) Having run the cable, he plugs it into the FDH and re-traces his steps, stapling or affixing the riser cable through risers, along staircases or even up exterior walls.
Similarly, in each dwelling he attaches an OLT (optical line terminal) in the customer’s dwelling and then runs a preterminated fibre back to the FDT. Stapling along architraves, skirting boards and through door frames and the like as he goes. Once again he simply plugs the second preterminated end of the customer fibre into a port in the FDT.
Finally, because the fibre cables are all factory pre-tested, the only testing that is needed is to check for signal levels in each customer dwelling.
With this novel approach, the whole process is every bit as simple as running in old-fashioned copper cable!
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