SB4

As shown in Figure 1, sandbox 4 consists of 8 nodes and a WiMAX subsystem that consists of a basestation and a controller. To prevent interference, each node is housed in ​Ramsey Electronics RF enclosure that provides 80 dB of isolation. Nodal wireless devices (Atheros 5000X mini-PCI card and Intel 6250 mini-PCIe 802.11/802.16) are connected to a power combiner and fed through the enclosure access port to the outside SMA connector which is wired to one of the input/output ports of the ​RF Transceiver Test System from ​JFW Industries. This configuration enables fairly tight control of RF attenuation matrix between the nodes. The topology is controlled through the ​OMF based Instrumentation AM.

RF Matrix Control Services

This service controls the RF attenuator matrix. Since there are a total of nine (9) input/output ports on the attenuator matrix, the first 8 input/output ports are connected to nodes 1 thru 8, respectively. The 9th input/output port is connect to the Wimax base station (BS). So in a nutshell

RF Matrix Port	Attached device	Additional attenuation values
1	node1-1	*
2	node1-2	*
3	node1-3	*
4	node1-4	*
5	node1-5	*
6	node1-6	*
7	node1-7	*
8	node1-8	*
9	wimax BS	*

Attenuation values between the eight (8) nodes and the BS can be controlled individually with the following URL commands listed below.

1. set - to set attenuation value on given port pairs (example portA=1 , portB=2, attenuation = 20)
   

This would set the attenuation value between node1-1 and node1-2 to 20 dB.

$ wget -O status http://localhost:5052/instr/set?portA=1\&portB=2\&att=20

2. get - to get attenuation on a given pair of ports

$ wget -O status http://localhost:5052/instr/get?portA=1\&portB=8

3. status - to get attenuation values on all port pairs

$ wget -O status http://localhost:5052/instr/status