Mx-DMA®

Building on the well-established, award winning Mx-DMA® HRC (High Resolution Coding) technology, Mx-DMA MRC (Multi-Resolution Coding) offers unprecedented service agility, extending the availability of Mx-DMA to very large networks and expanding the applicability and use of the technology to include a full spectrum of use cases.

Mx-DMA MRC brings forth the full scalability of TDMA return link technologies to the original Mx-DMA HRC return at the same SCPC-like efficiency levels. Service providers can cover a myriad of use cases in a single return link, from cruise ships and large enterprise customers to SCADA and broadband access, sharing satellite capacity more efficiently over a group of satellite terminals and applications achieving the lowest Total Cost of Ownership (TCO).

Mx-DMA MRC is a return link technology that combines the benefits of MF-TDMA (ideal for bursty traffic and higher contention services) and the spectrum efficiency of Mx-DMA HRC into a single return technology suited to a greatly expanded set of applications. Mx-DMA MRC scales in MHz independent of the number of terminals so customers may be served with a single return link for the majority of their use cases, minimizing operational complexity and maximizing statistic multiplexing. Designing an Mx-DMA MRC link does not require precise knowledge of the traffic and terminal mix as the link self-optimizes in real time. Moreover, the high efficiency enables bandwidth savings, higher throughput, better network availability and substantial terminal cost savings.

ST Engineering iDirect’s Mx-DMA® is a patented, efficient and dynamic multiple- access waveform which enables service providers to share satellite capacity more efficiently over a group of satellite terminals.

The Mx-DMA HRC (High Resolution Coding) return technology adjusts the frequency plan, the symbol rate, the modulation, coding and power in real-time for every terminal in the satellite network. These adjustments are based on the return traffic demand, the network Quality of Service (QoS) management and channel conditions for the terminal population in the network.

Within the Mx-DMA HRC return link, each carrier is assigned to only one terminal, achieving SCPC-like maximum return efficiencies. At the same time, the flexibility of MF-TDMA can be maintained as Mx-DMA allocates bandwidth based on real-time demand from each terminals and QoS profiles. In other words, as the traffic demand for a remote terminal changes, bandwidth will be allocated on the fly. If the traffic within the terminal becomes more important, extra bandwidth will be assigned to the carrier assigned to the terminal based on QoS and priority rules. The entire allocation operation is performed seamlessly without any data packets being lost.

Mx-DMA leverages the highly efficient High Resolution Coding technique making it particularly well suited for low-to-high data rate applications between 32 kbps and 200 Mbps. HRC provides a level of efficiency comparable to DVB-S2 with a 5% roll-off factor in order to get as many bits through the available bandwidth as possible. HRC optimizes low-to-medium rate traffic and avoids latency over satellite by using short block codes.

Mx-DMA MRC introduces several key advances:

1. High Resolution Bandwidth Allocation: Mx-DMA MRC redistributes the available spectral resources 25 times per second, allowing it to seamlessly adapt to changing traffic demand and link conditions. Minimum transmission lengths of 5ms tied to a symbol rate of 100kHz, ensure industry-leading granularity in bandwidth assignment, lowest latency and jitter, and highest efficiency for any traffic profile.
2. Scalable Demodulator Technology: Mx-DMA MRC supports minimum transmit lengths of 5ms, allowing up to 5,000 active terminals with a single multi-carrier demodulator, resulting in less hardware needed at the hub side.
3. Adaptive Payload Length: Mx-DMA MRC adapts the payload length in real time versus using pre-coded static payload length like other technologies, resulting in important efficiency gains across all applications, from low-rate bursty traffic profiles to high-rate traffic profiles.
4. Unsolicited logon: Terminals not passing traffic will log-off and restart transmission with an unsolicited logon mechanism when needed. This means that there is no idle capacity consumption.

These innovations come on top of the many great features of Mx-DMA HRC:

1. Highest MODCOD granularity and high MODCOD support: ensures that each terminal operates at the highest MODCOD sustained by its link budget. Mx-DMA MRC even improves on this with support for modulations up to 64APSK.
2. Low roll-off: No unnecessary loss of capacity with 5% roll-off.
3. Self-organizing return link: The return link collects all inputs in real-time and assigns the bandwidth autonomously to the entire population dynamically. There is no need for predefined carrier planning.
4. Automatic regrowth control: Ensures each terminal operates at the highest MODCOD, taking into account regrowth caused by BUC nonlinearities.