The core hardware elements of the TitanMIMO-4 testbed series include:
- The central baseband processing engine (available in either single FPGA or distributed cluster FPGA configurations).
- The subgroup processing FPGA, used to interface with the RF front ends.
- The RF front ends.
- The Rear Transition Module which allows for point-to-point inter-FPGA communications.
Central Baseband Processing
The central baseband processing engine of the TitanMIMO-4 has two distinct processing configurations which vary based on the number of FPGAs used for processing.
TitanMIMO-4S: Single FPGA Central Baseband Processing
In the case of the single FPGA central processing engine configuration present in the TitanMIMO-4S, the signals exchanged with the upstream/downstream FPGA subgroups all feed into a common master central processing engine, which is Nutaq's Perseus 6113 powered by a large Virtex-6 SX475T. The board also includes two FMC-HPC expansion sites and 4GB of SDRAM memory as well as the FPGA IP cores to read and write into this memory at very high speed. The Perseus 6111 also contains the logic to handle high speed PCIe or GigE data exchange with a host controller CPU for the M.MIMO communication upper layer protocols.
Subgroup FPGA Processing
In both the single & distributed FPGA central processing engine configurations, each subgroup is comprised of multiple double-width Perseus 6111 AMC boards. Each Perseus 6111 has a Virtex-6 LX550T and two FMC-HPC sites that enable connectivity with the radio front-ends.
Each Perseus 6111 can support two 2×2 MIMO Radio 420M boards, yielding four transceivers per AMC. The Perseus 6111 serves as a processing unit as well as an enabler for the Aurora interface through the rear transition modules (RTM). The Perseus 6111 is also equipped with 4GB of SDRAM memory as well as the FPGA IP cores to read and write into this memory at very high speed. The Perseus 6111 also contains the logic to handle the radio front end's functions and set the RF parameters dynamically (frequency, bandwidth, amplification of the signal, high speed AGC, etc.)
Radio Front End
The RF front end function of the TitanMIMO-4 is supplied by the Radio 420M. It is a powerful multi-mode software defined radio (SDR) transceiver with two channels (2 Tx and 2 Rx).
The Radio 420M is built around the multi-standard, multi-band Lime Microsystems LMS6002D RF transceiver IC, which supports broadband coverage as well as FDD and TDD full duplex modes of operation.
The front-end converts bandpass to baseband with no intermediate frequency (IF). I and Q samples are sent to the FPGA on the Perseus 611X for baseband processing or can be transferred to another device.
The Radio 420 is ready-to-use and supplies maximum performance due to its included auto-calibration features (IQ imbalance, DC offset and LO-leakage).
Rear Transition Module
The MicroTCA.4, double-width AMC Rear Transition Module (RTM) for the Perseus 611X expands the I/O capability to levels needed for Massive MIMO testbeds, overcoming the bottlenecks introduced by interfaces such as PCIe.
On the back plate, 7 miniSAS connectors are available, providing each an Aurora 4x high speed interface capable of handling 16 Gbps.
TitanMIMO-4 Hardware Components
Nutaq's TitanMIMO-4S and TitanMIMO-4D Massive MIMO testbeds are largely comprised of the same hardware components, with the exception of the central baseband processing engine card and the channel count (100×100 for TitanMIMO-4S, 100×100 for TitanMIMO-4D).
Perseus 6111 with LX550T FPGA
Perseus6113 with SX475T FPGA
|Kermode-XV6 with 8x SX475T FPGA||0||1|
Number of RTM Cards (for miniSAS)
uTCA Quad core i7
SSD Additional HDD 600GB
PCIe Expansion Card
Clocking distribution components