MCP Channel Unit Subsystem (CUS)

Square Peg Communications Inc.’s Multi-Channel Platform (MCP) is a hardware and software platform suitable for use in demanding satcom applications.

The MCP supports the implementation of Channel Unit Subsystems (CUSs) capable of supporting a variety of base station applications via a software-defined radio architecture. It conforms to industry standards for physical, electrical, and protocol interfaces to facilitate integration with other elements of the base station. It allows redundancy to be implemented efficiently where high availability is required.

The MCP also supports the implementation of physical layer testers, which are used to verify the performance of communications equipment intended for use in specific networks. A physical layer tester typically combines the transmit and receive capabilities of base stations and terminals with signal measurement functions and test automation facilities.

The architecture of the MCP is based on the use of a common LAN protocol for communication both within an MCP chassis and with other system elements. This provides a high degree of flexibility in configuring the system. For example, in addition to Channel Units, a CUS implemented with the MCP can include interfaces to terrestrial networks (e.g., T1/E1), as well as host processors to perform station management, network control, and call processing functions. The cards comprising a system can be distributed among multiple synchronized MCP chassis. All elements can be redundant for fault tolerance and high availability.

MCP-based Channel Unit Subsystems provide the modems for the Inmarsat-4 Classic Aero Ground Earth Stations (GESs) and BGAN Micro-Satellite Access Stations (Micro-SASs).

    • High availability
    • Hot swappable elements
    • Ease of maintenance
    • Scaleable number of channels
    • Scaleable signal processing capability
    • Flexible IF interfacing
    • Flexible baseband interfacing
    • High density
    • Excellent RF performance
  • Channel Unit Subsystem


    19” / 7U PICMG® 2.16, rack mount
    (4U, 12U also available)


    Front to back

    Power supplies

    N+1, AC or DC

    Shelf managers

    Dual redundant per PICMG® 2.9
    RCMP, CLI, GUI, SNMP interfaces
    Alarm dry contact relays

    Ethernet switches

    Dual redundant 10/100 or Gigabit

    Channel Units

    1 to 6 front / rear card pairs

    Channel Unit Front Card

    Composite channels

    4 Tx/Rx (independently tuneable)

    Composite channel bandwidth

    up to 1.25 MHz

    Bearer channels per composite channel

    Application-dependent; e.g., 4 for BGAN or Classic Aero

    DSPs per composite channel

    1 x 500 / 600 MHz TigerSHARC
    or 2 x 500 MHz TigerSHARC


    Xilinx Virtex 4 FX60

    DSP / FPGA communications

    1 full duplex link port @ 800 Mbps
    2 full duplex link ports @ 200 Mbps

    DSP expansion

    1 expansion connector per DSP cluster for off-board FPGA

    Control processor


    Ethernet interface

    Auto-switching between Switch A, Switch B and front panel

    Channel Unit Rear Card

    Number of IF feeds

    2 Tx + 2 Rx
    On-card loopback for self-test

    Tx/Rx IF frequency range

    50 to 90 MHz

    Max. total power per Tx feed

    –17 dBm

    Max. per-carrier Tx power

    Dependent upon number of bearers per composite channel, typically –29 dBm

    Tx phase noise density

    @ 100 Hz:   ≤ –70 dBc/Hz
    @ 1 kHz:     ≤ –80 dBc/Hz
    @ 10 kHz:   ≤ –90 dBc/Hz
    @ 100 kHz: ≤ –100 dBc/Hz

    Tx spurious

    < –86 dBm for carrier at –29 dBm

    Tx 3rd order intermodulation

    < –55 dBc (2 carriers at –20 dBm)

    Tx I/Q imbalances


    Typical Rx dynamic range

    –65 to –25 dBm
    –10 dBm max total

    Reference input

    10 MHz

  • MCP CUS Data Sheet

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