The old DVB-C standard has been used since 1994. The second generation standard came into effect during 2006 when European cable operators conveyed large concerns about the limited bandwidth they have utilise for the distribution of their services. The main aim was to use of the available bandwidth in cable networks more efficiently. Subsequently the DVB-C2 standard was created by experts from 20 various companies and scientists from numerous universities. Chairmanship of the endeavour was supplied by one of Europe’s major cable operators, Kabel Deutschland. Happily, the standard was finalised last year and supplements the DVB-S2 and DVB-T2 standards developed earlier.
The demand for more effective utilisation of coaxial cable bandwidth is logical. Despite the fact that in satellite TV it’s sufficient to move the dish to a different satellite and once more receive a frequency spectrum of 1 or 2 GHz, this can only be achieved with cable TV if you put in additional cables and, let’s face it, nobody wants that. The rising competition from IPTV plus the increasing interest in HD channels has finally put pressure on cable operators to take necessary action.
DVB-C has extremely efficient modulation and error correction schemes which are much more effective than DVB-S and DVB-T. Improving it substantially in DVB-C2 was by no means an easy feat. However, they triumphed! In the worst case, DVB-C2 provides a 30% gain in spectral efficiency over DVB-C. This number jumps up to 80% when upgraded from DVB-C based on 64-QAM. But even a 30% increase lets providers transmit 60 Mb/s through a 6 MHz channel (the maximum for 256-QAM in DVB-C is only 38.47 Mb/s)
Remember: HD Channels require roughly 20 Mb/s. The higher quality SD channels demand 4-5 Mb/s while most will typically use only 2-3 Mb/s. Regarding bandwidths, there are 6 and 7 MHz channels in coaxial cable TV Channel Plans. Yet, DVB-C2 allows the creation of wider channels with much higher bandwidths. Such a new wide channel does not have to be necessarily a multiple of 6 or 8 MHz. The bonus is that we do not waste bandwidth for channel separation and the spectral efficiency goes even higher.
Read more: Tele Satellite
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