"GEDOMIS at CTTC"

The GEDOMIS® testbed is an ideal platform to develop, test and validate the PHY-layer of modern wireless communication systems covering the prototyping and verification requirements of advanced solutions that target base stations, smart antennas, MIMO systems, Software-Defined Radio (SDR), geolocation, cognitive radio and high-speed test and measurement campaigns. In the past it has been used to develop and test real-time systems based on the IEEE 802.11, IEEE 802.16 and 3GPP rel. 9 standards. GEDOMIS® is able to host PHY-layer prototypes of multi BSs and multi User Equipments (UEs). A non-exhaustive list of supported PHY-layer development scenarios is given in table 1 (e.g., according to the number of transmitters-receivers, the number of antennas at each end, the transmission scheme and the signal bandwidth). A schematic representation of GEDOMIS® is given in the following block diagram, which includes the majority of the hardware equipment and boards used in the default set-up of the testbed (the main specifications of the instruments and boards are summarized in the table 2).

 

Number of Tx - RxNumber of antennas Tx- RxAntenna SchemeDL with emulated ULDL and ULBandwidth (MHz)
1-1 4x4 [1]
MIMO yes no up to 10
1-1 2x2 MIMO yes no 20
1-1 1x2 SIMO yes no 20
1-1 2x1 MISO yes no 20
1-1 2x2 [1]
MIMO - yes up to 10
1-1 1x2 SIMO - yes up to 10
1-1 2x1 [1]
MISO - yes up to 10
4-4 [1] 1x1 SISO yes no up to 10
2-4 1x1 SISO yes no up to 10
1-3 1x1 SISO - yes (for the Tx) up to 10
2-2 1x1 SISO yes no 20
2-2 [1]
1x1 SISO - yes (for the Tx) up to 10
2-2 [1] 2x2 MIMO yes no up to 10
1-2 1x2 MISO yes no up to 10

Table 1: Indicative PHY-layer development scenarios supported by GEDOMIS®.

 

GEDOMIS® can be used to develop:

      i.     Offline testbeds which typically combine Matlab simulations at the two baseband ends -transmitter and receiver- with instrumentation for the signal conversion (DACs, RF up-conversion, channel emulator or antennas, RF downconversion, ADCs). Offline testbeds are typically used to evaluate quasi-static channels.

     ii.     Real-time testbeds which feature an end-to-end full real-time operation able to validate realistic mobility and fast fading channel conditions.

 

Multi-antenna

transmitter

Baseband & IF signal generation: VHS-DAC board (Nutaq)

1 Xilinx Virtex-4 XC4VLX160 FPGA, 4 dual TI DAC5687 D/A (14-bit, 480 MSPS)

RF up-conversion: Agilent ESG4438C

2 Vector Signal Generators (250 KHz to 6 GHz)

Radio channel

Real-time channel emulation: Elektrobit Propsim C8 radio channel emulator

User-designed or standard channel models (350MHz - 6GHz, 70 MHz bandwidth)

Multi-antenna

receiver

RF down-conversion: Mercury Computer Systems Echotek Series RF 3000 Tuners

1 synthesizer and 4 tuners (20 MHz to 3000 MHz RF-to-IF, 65 MHz bandwidth)

AWGN generation: Applied Instruments NS-3

2 white noise signal generators (5 MHz to 2.15 GHz)

Signal acquisition & baseband: VHS-ADC, DRC, SMQUAD boards (Nutaq)

4 dual AD6645 A/D  (14-bit, 105 MSPS), 1 Xilinx Virtex-4 XC4VLX160 FPGA

2 Xilinx Virtex-4 XC4VSX35 & 2 XC4VLX160 FPGAs, 4 TSM320C6416 DSPs

Table 2: The main specifications of the hardware equipment and boards comprising the testbed

 

Gedomis

Schematic diagram of the default set-up of the GEDOMIS® testbed

 

GEDOMIS® has been used in the past in numerous occasions to implement, test and validate the PHY-layer of various wireless communication systems. The implemented R&D projects were funded either through public competitive calls (at national or European-level) or from direct contract with industrial players. It is worth to lay particular emphasis on two of them, due to their demanding and challenging development and verification cycle. Likewise it is demonstrated the upper bounds capabilities of the use-cases that can be implemented and tested in GEDOMIS®.

  • An important system developed in GEDOMIS® was part of the BuNGee project, funded by the EC (FP7, ICT call 4, STREP, finished September 2012); the result of this project was a real-time FPGA-based implementation of the PHY-layer of a MIMO closed-loop wireless communication system based on the IEEE 802.16e standard. The system featured a wide signal bandwidth and a sophisticated RTL design that accommodated concurrently two transmission schemes, two symbol permutations and adaptive subcarrier allocation and transmit antenna selection, according to timely-generated and transmitted CSI feedback.
  • Another important system developed in GEDOMIS® was part of the BeFemto project, funded by the EC (FP7, ICT call 4, IP, finished September 2012); the result of this project was a real-time FPGA-based implementation of the PHY-layer of an LTE-like system featuring interference management. In more details, the primary DL communication of a Macro BS and a Macro UE is interfered by a secondary DL communication between a Femto BS with a Femto user, because both DL signals have the same BW and use the same RF band. The interference was mitigated to protect the QoS of the primary DL communication.

Finally, apart from NEWCOM#, GEDOMIS® has been used or is currently used in other projects; the most representative ones are listed hereafter: MIMOWA (MEDEA+, finished in September 2009), EMPhAtiC (FP7, ICT call 8, STREP, started September 2012), GRE3N (funded by the Spanish Ministry MINECO, started in January 2012), GEDOMIS-ADCOMM (finded by the local Catalan Government, started January 2011), BeMImoMAX (IP licensing through Nutaq Inc, started October 2011).



[1] Using to 2 extra E4438C Vector Signal Generators from Agilent which are not available at GEDOMIS but could be made available (authorization is required since they belong to other research areas at CTTC).

 

Newcom#

This laboratory is supported by the European Commission in the framework of the FP7 Network of Excellence in Wireless COMmunications NEWCOM# (Grant agreement no. 318306).

7 Framework Programme

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