Current UHD broadcast channels are encoded by high efficiency video coding (HEVC) and modulated by DVB-S2. HEVC is the latest video compression standard. Compared to H.264, it doubles the compression efficiency while maintaining the subjective quality of the video. DVB-S2 is the widely adopted standard in satellite broadcasting/communication. However, with the launch of high data rate services (e.g. UHD), DVB-S2 standard is no longer adequate to meet today's high throughput need.{mosimage}

Introduction of DVB-S2X

DVB-S2X is the new DVB standard published in October 2014. It offers higher flexibility and more features than the core applications of DVB-S2. Compared to DVB-S2, efficiency gains up to 51 percent can be achieved with DVB-S2X.

"The timely approval of DVB-S2X means it can be implemented with HEVC, the latest video coding scheme. It is anticipated that the volume demand for chip sets and equipment will be driven by consumer Internet services and broadcasts of UHDTV with HEVC coding via DTH satellites," stated in the press release of DVB-S2X specification approval.

Characteristics of DVB-S2X for UHD DTH Broadcasting

DVB-S2X boosts the satellite throughput up to 20 percent in direct-to-home (DTH) networks compared to DVB-S2. The most relevant features of DVB-S2X to achieve such benefits are channel bonding, advanced filtering of carrier spacing, wideband technology, finer granularity of modulation, and forward-error correction (FEC) options combined with sharper roll-offs. DVB-S2X also has features to improve the service robustness and feasibility in satellite DTH networks. Additional scrambling sequences reduce the co-channel interference in multi-satellite environments. Variable coding and modulation (VCM) allows the changes of modulation and coding (MODCOD) in frame-by-frame basis to increase the feasibility of DTH service; broadcasters thus can balance the broadcast quality and service robustness according to their needs.

The availability of DVB-S2X-compliant silicon chip is a key element for the market success of UHDTV, set-top boxes (STBs), and satellite modems. Semiconductor manufacturers such as Broadcom, Silicon Labs, and ST Microelectronics have implemented the new DVB-S2X standard on their DTH and broadband system-on-chip (SoC) devices.

With these DVB-S2X-compliant chipsets, manufacturers can design and produce future-ready satellite UHD devices. STBs and iDTVs with DVB-S2X and HEVC capability are expected to be launched in late 2016.

Not only chipset vendors but also providers of professional satellite transmit-and-receive equipment are supportive of the launch of DVB-S2X. For example, Newtec, Comtech, Ericsson, Creonic, Work Microwave are either developing or have developed DVB-S2X modulators/demodulators and complete set of solutions.

Economic Viability of UHD Delivery using DVB-S2X

There are two approaches - distribution and cable TV headend - to deliver UHD with DVB-S2X via satellite. Small antennas are used for distribution networks such as DTH service while headends such as TV stations tend to use larger antennas for reception.

In short term. Cable TV headend will be the forerunner in UHD transmission with DVB-S2X. It involves a limited number of equipment, and the use of large antenna to enjoy the benefit of throughput increment of DVB-S2X. The significant throughput increase could compensate the cost of the change of new equipment.

For distribution, only few DTH platforms will change to DVB-S2X in the near future as the gain in throughput is not enough to absorb the cost of replacing tens of thousands of STBs. Less than 20 percent throughput increment can be obtained for a DVB-S2X DTH network via conventional satellites due to the limitation of receive-dish size.

In long term. It is expected that like DVB-S2, DVB-S2X will become the mainstream. With more UHD content, enhanced HEVC compression efficiency, manageable cost of DVB-S2X equipment (e.g., STBs and modems), and launches of HTS, in the longer term the new DVB-S2X will be economically viable for UHD DTH networks. DVB-S2X showcases an evolution and enhancement of the DVB-S2 standard and offers significant advancement in the next-generation DTH broadcast services. While the standardization of DVB-S2X and UHDTV has taken the broadcast industry a step forward, the launch of DVB-S2X commercial products will revolutionize the current DTH market. With enhanced technologies, UHD satellite transmission with DVB-S2X will become the benchmark of the new-generation DTH service in the next decade.