wiki:Hardware/bDomains/aGrid

Version 39 (modified by jkol, 6 years ago) ( diff )

Grid

Block diagram of the ORBIT Grid domain is shown in Figure 1. The main components of this domain are:

  • Grid nodes: 20 x 20 machines arranged in a grid configuration (20 rows with 20 nodes each) with spacing of 3 feet.
  • Massive-MIMO racks: four mini-racks of SDRs with 32 antennas each
  • Servers: number of servers of varying capabilities
  • Virtual machines: number of on-demand VM instances
  • Noise injection subsystem: for injecting arbitrary signals to create different topologies
  • Support infrastructure: SDN capable ethernet switches, GPS/RF reference distribution, console and other support hardware
ORBIT Grid Block Diagram
Figure 1: ORBIT GRID

Massive-MIMO mini-racks

There are four mini-racks located in the corners of the Grid specifically for massive-MIMO experiments. Each rack contains 8 Ettus USRP X310 software defined radios outfitted with two UBX 160 radio daughterboards each. PPS and 10MHz synchronization signals are distributed among the USRPs in each rack via an Octoclock based timing distribution system. Equal length cables are used to ensure minimum timing deviation within and between the racks allowing for all USRPs across the four racks to by synchronized. Additional hardware is present in each rack to allow for power-cycling and "imaging" of the USRPs in a similar manner to standard nodes.

Massive-MIMO mini-rack
Figure 2: Massive-MIMO mini-rack

Servers

A number of high CPU core count/large memory servers are available for running "backend" software. Some are equipped with GPUs for increased computational performance.

Noise Injection subsystem

The Centralized Arbitrary Waveform Injection Subsystem (CAWIS) consists of arbitrary waveform generator (Agilent ESG) connected through a distribution network to four multi-band antennas located in the four corners of the grid. The distribution network enables control over the attenuation of the individual antenna feed. Using CAWIS, users can inject (among other types of waveforms) AWGN signals into the main ORBIT grid and thus create different topologies.

Noise Antennas in the Grid
Figure 2: CAWIS
Interference Injection Subsystem Block Diagram
a.) Block Diagram b.) Noise injection antenna positions

As most of the Orbit services, CAWIS is a web-based service accessible from the main grid console through url: http://instrument1.orbit-lab.org:5054/interference. As with other aggregate managers, accessing this url without any other arguments will show it's usage reference page.

Support Infrastructure

Attachments (4)

  • noiseantenna.png (197.6 KB ) - added by Surya Satyavolu 16 years ago.
  • ORBITGridBD.jpg (114.3 KB ) - added by seskar 10 years ago. ORBIT Grid Block Diagram
  • CAWIS.jpg (70.4 KB ) - added by seskar 10 years ago. Interference Injection Subsystem Block Diagram
  • Massive-MIMO.jpg (163.8 KB ) - added by seskar 6 years ago. Massive-MIMO mini-rack

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