==== SB4 ====
[[TOC(Hardware, Hardware/bDomains, Hardware/bDomains/cSandboxes*, depth=6)]]

As shown in Figure 1, sandbox 4 consists of 10 nodes and two LTE and two WiMAX basestations and corresponding BS controllers. To prevent interference, each node is housed in [http://www.ramseytest.com/ Ramsey Electronics RF enclosure] that provides 80 dB of isolation. Each of the 9 nodes is equipped with a pair of WiFi devices: one Atheros 5000X mini-PCI card and one Intel 6250 mini-PCIe 802.11/802.16. 4 nodes are also equipped with [wiki:Hardware/fDevices/cSDR/gUSRP#USRPB205  USRP B205mini-i] SDR devices. All of the antenna ports of in each node 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 [http://www.jfwindustries.com/documents/50PMA-012_specsheet.pdf  RF Transceiver Test System] from [http://www.jfwindustries.com JFW Industries]. This configuration enables fairly tight control of RF attenuation matrix between the nodes. Four of the RF test system ports are shared between nodes and basestations (node1-1 and node1-2 are sharing their port with LTE baestations while node1-8 and node1-9 are sharing their ports with WiMAX basestations). The topology (including pairwise attenuation between ports and selection switches for node/basestation) is controlled through the [http://omf.mytestbed.net OMF] based [wiki:/Software/eAM/mInstr Instrumentation AM]. 

  || [[Image(SB4.png, 700px, align=center)]] || [[Image(IMG_0376.jpg, 200px)]] ||

As can be seen in figure 1, there are a total of nine (9) input/output ports on the transceiver test system. The first 7 input/output ports are connected to nodes 1 thru 7, respectively while the 8th and 9th input/output ports are connect to  either nodes 1-8 and 19 or the two Wimax base stations (BS1 and BS2). The selection of devices attached to ports 8 and 9 is controlled by the ''selDevice'' command of the [wiki:/Software/eAM/mInstr Instrumentation AM] service. 

 || RF Test System Port || Attached device || 
 || 1 || node1-1 ||
 || 2 || node1-2 || 
 || 3 || node1-3 || 
 || 4 || node1-4 || 
 || 5 || node1-5 || 
 || 6 || node1-6 || 
 || 7 || node1-7 || 
 || 8 || node1-8 or wimax BS1 || 
 || 9 || node1-9 or wimax BS2 ||

This configuration creates two distinct set of RF paths that are used to create various topologies.

===== Node to Node RF Path =====

s12 parameters taken with Agilent ENA RF Network Analyzer E5070; instrument dynamic range of 110 dB limits the accuracy of large attenuation results.

[[Image(SB4-Equiv-WiFi.jpg)]]


|| [[Image(S12-A-24.jpg, 250px)]] || [[Image(S12-A-25.jpg, 250px)]] || [[Image(S12-A-52.jpg, 250px)]] ||
 
===== Node to WiMAX basestation RF Path =====

[[Image(SB4-Equiv-WiMAX.jpg)]]

[[Image(S12-B-25.jpg, 400px)]]