James Pittman on why multiplexing doesn't work
The digital revolution was meant to be magnificent. It was meant to continue, improve and extend upon what we already had in television and radio and give us better quality and greater quantity at less cost.
Sadly we all know that the truth is somewhat less rosy than this. After less than five years from their launches, digital terrestrial broadcasting has already gone through one major disaster that it will take some time to shrug off, whilst the listeners of digital audio broadcasts are getting more and more disenfranchised as every day their broadcast quality decreases.
Most people would argue that there are many reasons for this - I argue that there is just one - the humble multiplex.
Multiplexing is the wonderful technique whereby several signals - in this case digital audio radio signals or digital visual/audio television signals - are combined into a single signal for transmission down one line or one frequency.
It is a technique that is used in practically all digital broadcast media due the fact that compressed digital signals take up considerably less bandwidth than their analogue counterparts and results in the desirable fact that several stations can be crammed into the space of one.
From a technical point of view this is fantastic. It means more channels of an equal or higher quality to that of analogue can be fitted into the same space. The problem comes when you get to the logistics of actually giving this wonderful new medium to the broadcasters.
Traditionally the government would allocate frequency space for television and radio on a local station by station basis and then give this station space to either the BBC for its own use or for the IBA (and later the ITC/Radio Authority) to allocate to a commercial organisation. Broadcasters could not just find a nice quiet looking bit of the spectrum and set up transmissions there.
Procedures had to be followed and station frequencies were allocated in a way that led to the best coverage and the best reception and picture/sound quality for the listeners and viewers. It is a matter that the powers-that-be never took lightly.
When it came to licensing and allocating these channels in the commercial sector, as much care was also taken. The IBA had to make sure its licensees would provide as best a service as possible and required them to have very detailed proposals of what would be carried on these precious signals.
If they failed in this then they would loose their franchise to broadcast on this frequency next time the franchise was up for renewal, something companies painfully found out over the years.
Privatisation of the ITC
This system worked very well until the multiplex or 'mux' came onto the scene. The problem was that the government allocated frequencies for digital multiplexes in just the same way it had always allocated them to single analogue stations in effect allowing the space for half a dozen or more radio stations to be given to one organisation with one franchise agreement at any one time.
In 1996 the government decided to allocate frequency space to digital terrestrial television to start broadcasts in 1998. Whilst there was space for in excess of thirty TV channels it only allocated a mere six licences, one for each multiplex.
One of the multiplexes (the one with the best coverage) went to the BBC, one to the existing commercial terrestrial broadcasters, and the rest to the ITC to find contractors to be given franchises. The doomed ONdigital received three of the multiplexes and half of the platform's capacity, with the rest going to the state-owned S4C's consortium SDN.
The ONdigital multiplexes have since been re-allocated by the ITC to a consortium of the BBC and Crown Castle, the company that acquired the BBC's transmitters after the Conservative's programme of television deregulation we know so well.
The original multiplex holders had to come up with some detailed arguments as to what they'd do with the space but other than a requirement for the six existing analogue stations to be carried, what channels the broadcasters filled the space with and even how many they filled it with was essentially entirely up to them.
Try to imagine the ITA in the 1950s allocating the broadcasting rights for all of ITV to three companies and requiring them to be the judges of which regional company best provided the local service.
When ONdigital, the owner of three multiplexes, started its pay television service if filled the space with channels the ITC had no part in deciding upon.
None of ONdigital's channels had individual ITC franchises to broadcast on terrestrial like the channel 3 franchise holders do. As a result of this, when ONdigital decided upon the business plan that would later see the company go bust, the ITC was powerless to do anything to stop it.
ONdigital, as well as SDN, were perfectly within their rights to add channels on the basis of profit and ignore quality or public service commitment.
As a result we saw the precious space that was Digital Terrestrial become full of porn channels, pay-per-view film channels, shopping channels and unpopular niche channels such as Carlton Food Network and Wellbeing that were coincidentally owned or run by ONdigital's parent companies Carlton and Granada. Even ITV Sport didn't have to apply for a specific DTT licence from the ITC.
Broadcast quality was also a factor. In a desperate bid to compete with Sky, ONdigital was desperate to provide as many channels as it possibly could and as a result it considered broadcast quality should play second fiddle.
With Digital Multiplexing, the amount of channels that can be carried may be increased at by reducing the station's broadcast quality. In addition, formats of broadcasting can be used which allow also for lesser coverage but more channels to be carried. This was a practice ONdigital undertook shamelessly.
So how do I propose things be done differently? Well allocate not multiplexes but channel space within the multiplex. Allocate digital stations to actual station broadcasters not multiplexes as a whole. If DTT can carry 30 channels then 1996 should have seen 30 channel franchises up for grabs (or 24 if you want some reasonable quality).
Not only would the regulator have had the absolute scrutiny as to every last channel that was being carried, but if a particular channel didn't make a success of its digital outing it could give up or have its franchise re-allocated with minimal fuss and disruption of the platform as a whole.
If one company that holds the licence for half of the channels doesn't make a success of itself then the entire platform is almost destroyed overnight, as we all so sadly saw. Clearly a case of putting all your eggs in one basket and the basket being dropped.
Sometimes you need co-ordination, for example it was ONdigital that dealt with the logistics of sticking the stations into one broadcastable and encrypted signal and dealing with subscriptions.
But when problems like this arose in the past everyone pitched together and created ITN, Oracle or the TVTimes. The ITC could have additionally allocated a franchise for a company to handle subscriptions and a second company to handle encryption and broadcast.
The pile em high and sell em cheap phenomenon that DTT suffered from has made a mockery its radio equivalent, DAB. In 1998, the Radio Authority began the process of handing out franchises to broadcast on a platform everybody had firm hopes would provide a truly superior alternative to analogue radio.
DAB could offer more stations and a better quality of sound to the listener. The Radio Authority sadly didn't offer licences on a station by station. Instead they offered out a national multiplex and up to three regional ones to provide a service alongside whatever the BBC decided to carry on its own national mux.
This initially worked very well until the franchise holders and the BBC alike decided they wanted more and more stations to be carried on the platform. There is now no argument that the broadcast quality of DAB is better than existing radio. Even what the BBC puts out is inferior to that of the good FM stereo radio most people get.
We are now in a no-win situation as DAB does indeed carry many new services such as 1xtra, 6music, MinistryOfSound and AbracaDABra, but if it doesn't offer what most people want - existing stations in a much superior quality - then what's the point? With Digital Satellite - a far more abundant piece of equipment in the average home than a digital radio - now offering a better service, DAB seems to be offering very little.
Had the Radio Authority been required to allocate licences on a per-station basis and had the BBC been given station-sized parts of multiplex space by the government on a similar basis, then quality could have been ensured.
Imagine if the government had long ago said to the BBC that it can have half of the FM spectrum to do with whatever it likes and that the rest would be given to a single commercial company. There would be a lot more stations out there but whether the quality and coverage would be anywhere near the same is anybody's guess.
And then there is the fairness factor. With one company owning the space for six radio stations then it is far more likely to use that space to carry stations it owns or is affiliated with, thus making the whole commercial market an unfair and unequal one where the multiplex owner is the true regulator.
A simple oversight in how frequency space has been allocated has lead to serious damage in what were meant to be the two flagship platforms of digital broadcasting.
Digital Satellite has only been able to avoid this problem due to its superabundant bandwidth, which allows it to be reckless with how it allocates its space. With the terrestrial broadcast media this is not possible and the true control that needed to be implemented was not.