Digital Terrestrial TV and Mobile TV Networks

The Nimbra platform is deployed as the core technology in large number of national Digital Terrestrial TV networks, including Norway’s DTT network, the largest in the world. The Nimbra DTT networks does not only provide nationwide TV distribution. They also support additional services such as contribution for TV and radio, radio distribution, Mobile TV, IP non-linear production, contribution for live events, remote management to third party equipment, mobile backhaul, and so on.

Market

In Europe, Asia and Africa, there is normally one operator assigned to distribute TV signals to transmitters for the entire nation for all broadcasters. The infrastructure needs to carry a lot of TV signals to a large number of transmitters. Transmitters are normally located on mountain tops where no fiber connection is available. The last hop is usually a radio link with limited capacity like STM-1 or IP radios. As the operator upgrades or builds new digital infrastructure, it is natural to look for additional revenue sources from new services to leverage on their nationwide infrastructure. Such new services can be mobile TV distribution, mobile backhaul, contribution services for the broadcasters, or radio distribution.
In North and South America, each broadcaster typically supports and manages its own infrastructure. They have traditionally had to transport only a limited number of signals. However, capacity requirements have increased with the introduction of digital television and HD.
There are multiple standards in the different regions such as DVB-T, ISDB-T, ATSC, DMB-T, etc. but from a transport perspective they are very similar as they use ASI interfaces and MPEG transport so the transport requirements is quite similar. With the introduction of the DVB-T2, the requirement changes on the interface side since the encoders and the transmitters typically has Ethernet interfaces. Still the same network requirements with scalability, efficient multicast and BW utilization, etc. are the same.

Challenges

The challenges when upgrading the terrestrial infrastructure can be summarized as:

  • Rapid deployment - New nationwide infrastructure must be deployed in a few years.
  • Efficient usage of link capacity - The capacity to the transmitters are limited since they are normally reached with radio links supporting E3/DS3, STM-1/OC3 or IP radios with maximum 200 Mbps.
  • Reliability - National TV distribution is mission critical to governments. These systems require advanced redundancy and disaster recovery schemes to handle network faults.
  • Large scale multicast - The distribution of the TV signals needs to reach a large number of transmitters.
  • Multi-Service - To have a fast Return of Investment on the infrastructure, several services must be accommodated in the infrastructure.
  • Reliable distribution of time to transmitters - Many installations use Single Frequency Network (SFN) operation. Distribution of accurate time signals (1 PPS and 10 MHz) to the transmitters is crucial for reliable operation.

Net Insight offering

Net Insight’s Nimbra platform is the leading transport solution offering the most reliable transport network for digital TV distribution. Nimbra is a multi-service platform with advanced network management capabilities offering highly automated, plug-and-play operation when deploying large scale networks. Engineers can configure the systems and provision new services quickly and easily.
Nimbra offers the best link utilization on the market with its guaranteed transport and minimum overhead. For example, Nimbra let’s you add one or two extra multiplexers to an STM-1/OC3 circuit using the DVB-T standard compared to other products.
The Nimbra platform supports advanced network redundancy schemes assisted by an automatic control plane that offers mesh protection and 1+1 protection. Nimbra also has built in disaster recovery mechanisms to protect the head ends.
Nimbra has an optimized multicast scheme specifically designed for large scale TV distribution. This is assisted by simple point and click configuration and automatic mesh restoration. The multicast distribution forms an optimal distribution tree over any type of topology. 
The Nimbra platform is a multi-service platform with built in interfaces for media, datacom and telecom:

  • ASI supporting DVB-T, ISDB-T, ATSC and DMB-T
  • SD-SDI
  • HD-SDI
  • AES-EBU
  • E1/T1
  • E3/DS3
  • STM-1/OC-3
  • 10/100/1000 Base-X

The Nimbra platform supports network-based time distribution (1 PPS and 10 MHz) with built in protection. This means that you can distribute highly accurate time signals to the transmitters inband. This eliminates the need for GPS receivers at the transmitters and removes the vulnerabilities associated with GPS time distribution.

Key Benefits

The major benefits of the Nimbra platform for DTT networks are:

  • Highest link utilization on the market offering efficient usage of the precious radio link capacity
  • Mix of ASI, IP/Ethernet and PDH/SDH transport offering integration of all services in one platform
  • In-band management for remote management of Nimbra equipment and third party equipment at transmitter sites
  • Ability to integrate contribution services using compressed and uncompressed signals in the same infrastructure
  • Network-based time distribution replacing GPS receivers at the transmitters for SFN networks
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