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Demonstrator of Precoding Techniques for Flexible Broadband Satellite Systems

Beam hopping provides the means to flexibly adapt the offered capacity to the time and geographic variations of the traffic demands, while precoding exploits the multiplexing feature enabled by the use of multiple antenna feeds at the transmitter side to boost the spectral efficiency. These two effective strategies can create unique opportunities if they are properly combined.

The SIGCOM group has developed a SW-based tool to investigate the applicability of the “Cluster Hopping” concept.

In particular, the demonstrator considers the combination of beam hopping with precoding and designs the appropriate beam illumination approach. The introduction of precoding in beam–hopped systems is required when a set of adjacent beams is illuminated at the same time with the same frequency resources. We define such set of adjacent beams as cluster and we refer to the concept of “Cluster Hopping”. Therefore, the “Cluster Hopping” paradigm refers to a particular beam illumination pattern design which takes into account the interference issues brought into the beam–hopping scenario by the aggressive frequency reuse assumption.

System Architecture:

An important component of the system is the satellite resource manager, the entity that determines the cluster hopping transmission plan. It needs at its input the demand requirement from each terminal user and provides the plan to gateway, which allocates beams and time slots for the whole transmission cycle. The satellite is informed about the illumination pattern via TT&C. A simplified architecture is depicted in Figure 1, where the TT&C is collocated with the resource management unit.

Figure 1. Flexible broadband multi-beam satellite architecture

GUI overview:

The input parameters are divided into fixed and adjustable parameters. Here is the list of fixed system parameters:

Satellite orbit: GEO, 13-degree East
Beam Pattern: ESA-100
Loss: 5 dB (OBO + RF chain)

Adjustable parameters are:

Payload Power [Watt]
Transponder Band Width [MHz]
Operating frequency [GHz]
BH Window [time slots]
Time Slot Duration [msec]
Mode of Operation
- Cluster Hopping
- Beam hopping (designed by SnT)
- Beam hopping (designed by ESA)
- Clustering Option
  - Option 1 with 17 clusters of approx. 4 beams per cluster
  - Option 2 with 11 clusters of approx. 6 beams per cluster
  - Illumination Ratio
    - 1/4 (one out of four active beams)
    - 1/6 (one out of six active beams)
    - 1/8 (one out of eight active beams)
    - Traffic Time Instance
      - 1am from Traffic Emulator
      - 8 am from Traffic Emulator
      - 12pm from Traffic Emulator
      - Artificially Generated Demand 1
      - Artificially Generated Demand 2
    - Scheduling
      - Simplified (single user in the center aggregating all beam demand)
      - Demand-based scheduling (multiple users with different demands)
    - Capacity Selection
      - Shannon Capacity / DVB-based ACM capacity
    - Results including inter-cluster (or inter-beam) interference
    - Results ignoring inter-cluster (or inter-beam) interference

Once the program completes the requested calculations, the main results are shown directly on the GUI, including:

Demand: Overall system demand (aggregation of the 67 beams). Measured in Gbps.
Offered Capacity: This is the offered or so-called supplied capacity that is provided by the satellite. Measured in Gbps.
Unmet Capacity: This output shows the amount of overall system unmet capacity. Measured in Gbps.
Unused Capacity: This output shows the amount of overall system unused capacity. Measured in Gbps.

Visualization of the resulting illumination pattern is also possible, as well as different figures as listed in Figure 2.

Figure 2. Results Selection Drop-down Menu

References:

[1] M. Kibria, E. Lagunas, N. Maturo, D. Spano, S. Chatzinotas, “Precoded Cluster Hopping in Multi-Beam High Throughput Satellite System” IEEE Global Communications Conference (GLOBECOM), Waikoloa, HI, EEUU, Dec. 2019.

References:

This work has received funding from the European Space Agency (ESA) funded activity FlexPreDem: Demonstrator of Precoding Techniques for Flexible Broadband Systems. The views of the SIGCOM team do not necessarily reflect the views of ESA.

Web https://artes.esa.int/projects/flexpredem

Research Team