IDROMel aims at defining, developing and validating a powerful SDR platform combining very last technology progresses such as:

• a completely flexible baseband processing,
• MAGALI Network on Chip based integration,
• FPGA partial reconfiguration support,
• very wide band RF from 200 MHz to 7.5 GHz agility,
• 4 x 4 MIMO support,
• flexible MAC design for vertical hand-over support.

The features of the platform permits to explore many SDR scenarios. The scenario of a vertical hand-over between a cellular UMTS-like waveform and an ad hoc OFDM waveform is the demo target of the IDROMel project. The global baseband processing and management implemented in a PCIExpress / ExpressCard compatible card is composed of a Virtex-5 330LX and a Virtex-5 110LXT. The Virtex-5 110LXT is mainly controlling the PHY layer as well as providing a convenient interface to the host PC running the MAC and upper layers of the two protocol stacks. The Virtex-5 330 implements the digital baseband processing and is able to support up to 4 RF chains. The MAGALI NoC architecture will be showed briefly. It is capable of running a MIMO OFDM baseband transceiver at a data rate up to 100 Mbps. Many configurations are supported thanks to the parameterizable and reconfigurable approach of all processing units embedded in the NoC architecture. The Partial Reconfiguration has also been integrated in the NoC network through the extension of the network into a FPGA. This gives the capability to the system to evaluate and test this new feature of FPGA combining HW processing efficiency and SW flexibility. Details of the wide band RF architecture will also be given.

MAC layer

Each waveform protocol stack runs the MAC and upper layers on a Linux RTAI host PC connected to the hardware platform. A scheduling entity manages the vertical handover between the two targeted waveforms. In particular, the coexistence of the waveforms and the switch from one to the other are managed by this dedicated entity that is triggered by the measurements coming from the PHY layer, for example considering the SNR or throughput of the links.

Digital BB

The platform is planned to be pluggable to a laptop. It is driven by an embedded 32 bits micro-controller. The interface with the host PC is a 8x PCIExpress link. The baseband unit assembles 7 flexible processing units, each of them complemented with an 8 bits micro-controller and a DMA engine. These units are interconnected through an Advanced VCI crossbar interconnect. Several parallel and serial general purpose I/O modules are used to control the RF, interface with the AD/DA converters and to extend the system with daughter boards (e.g. a MAGALI chip).

Network-on-Chip support for reconfiguration

MAGALI chip is the successor of the FAUST one. Based on a Network-on-Chip architecture, it includes heterogeneous hardware blocs with specialized or generic functions. Optimized for a large set of operating conditions in terms of power/performance ratio, the reconfiguration features allow multi-application support as well as complex MIMO and OFDM schemes.

Partial Reconfiguration of FPGA

Partial reconfiguration of FPGA is a new feature that extends SDR perspectives while bringing the highest degree of flexibility to the HW domain. This permits to combine flexibility and processing power. This is allowed thanks to very short time of reconfiguration that are shown to go down to a few tens of microseconds to change an IP.

RF

From a RF point of view, the main objective of the proposed prototype is to show that a highly reconfigurable RF transceiver is possible with existing available components. Hence, the targeted prototype is very ambitious in term of frequency bands, since the objective is to address from 200 MHz to 7.5 GHz, with a maximum bandwidth of 20 MHz. Hence, we will be able to receive and transmit almost all the existing commercial Radio Access Technologies. Concerning the transmitted power, the target is comparable to existing GSM terminals (+21 dBm). On the receiver side, the objective is to have a noise figure from 8 to 12 dB, depending on the frequency band. The RF equipment includes up to 4 antennas and 4 RF chains.