SDR_Specification.pdf

Specification

Software Defined Radio Test Bed

Version 1.2

5/6/2016

Specification Software Defined Radio Test Bed

1. Scope

NRL requires, at a minimum, a 24-node RF channel matrix that is capable of supporting various types of channel conditions in order to design and test the performance of various types of transceivers. The purpose of this contract is to provide a software defined radio (SDR) test-bed for the NRL Code 5500, with the following components listed below:

1.1. Software defined radios (minimum of 32 transceivers)

1.2. Channel emulator (minimum of 24 nodes)

1.3. RF-shielded enclosures to house the SDRs

1.4. Racks/shelves to mount the equipment in

1.5. Cables required to connect the SDRs to the channel emulator and digital interfaces for existing computers

Specifications for these components delineated in Section 3, Requirements, below will be developed in coordination with Principal Investigator (PI) led research teams that may include Government scientists and other Contractors.

2. Applicable Documents

2.1. Department of Defense Specifications and Standards

None

2.2. Other Government Documents

None

2.3. Non-Government Documents

None

3. Requirements

3.1. Base Requirements for Channel Emulator/RF Matrix

3.1.1. The test bed shall include, at a minimum, a 24-node channel matrix.

3.1.2. The channel emulator/RF matrix shall support a variety of channel models and shall be capable of accepting new channel models via software upgrade.

3.1.3. The channel emulator/RF matrix shall support a 24-node full mesh network where full mesh means every node can communicate with every other node (including itself).

3.1.4. The channel emulator/RF matrix shall support ability to run multiple simultaneous networks using any combination of the 24 available nodes.

3.1.5. The channel emulator/RF matrix shall support RF input/output connections as well as digital (I/Q) input/output connections.

3.1.6. The channel emulator/RF matrix shall support full duplex operation for each of the 24 nodes, for both RF as well as digital (I/Q) input/output connections.

3.1.7. The channel emulator/RF matrix shall be controllable using a contractor-provided control node.

3.1.8. The channel emulator/RF matrix shall support a control Application Programming Interface (API) in order for external applications to provide full control over all 24 nodes.

3.1.9. The control API shall be fully documented such that a third-party control application could be developed.

3.1.10. The control API shall provide, at a minimum, the ability to control the channel characteristics for each node and the attenuation for each node in real-time and accurately represent dynamic wireless communication network conditions.

3.1.11. The channel emulator/RF matrix shall support integration of the NRL Extendable Mobile ad-hoc Network Emulator (EMANE) system that is running on external computer system via 1000BASE-T (1 GbE) network interface. Specifically, the device shall support dynamic control of channel parameters (e.g., path-loss, delay, etc.) via a network interface accessible via Ethernet using an Internet Protocol (IP) connection. A documented control application program interface (API) specification shall be provided that describes the specific mechanism.

3.1.12. The channel emulator/RF matrix shall support external node mobility control input via the control API described in 3.1.10. The specification of node location, velocity, and orientation should be supported for a GPS-referenced coordinate system. This information may be useful for detailed channel emulation purposes to account for ranging effects, Doppler shift, and other channel phenomena. Location should be expressed in floating point latitude, longitude, and altitude values that allow for 1 meter of positional accuracy.

Velocity should be expressed as a tuple with a magnitude in units of meters/seconds and GPS azimuth and elevation as a fixed bearing heading until updated. Orientation information is expressed as pitch, yaw, and roll with respect to velocity (with a default velocity of (0,0,0)).

3.1.13. The channel emulator shall support simulation of a platform that meets the threshold specifications stated in Table 1.

3.1.14. The channel emulator shall support a propagation channel model that meets the threshold specifications stated in Table 2.

Table 1: Simulations Threshold Specifications

Key Performance Parameters Threshold Objective

Minimum speed of platform 0 m/s (meters/second)

0 m/s (meters/second)

Maximum speed of platform 225 m/s 3333.33 m/s

Doppler shift @ 18 GHz, respective speed 13.5 kHz 200 kHz

Speed increment 1 m/s 0.5 m/s

Number of platforms in full mesh 24 32

Table 2: Propagation Model Threshold Specifications

Dynamic range – Link1 80 dB 90 dB

Instantaneous bandwidth 100 MHz 1 GHz

Minimum time delay with simple channel model2

33 ns 3 ns

Maximum time delay with simple channel model2

3.5 μs 3.5 μs

Time delay increment for simple channel model2

100 ns 1 ns

Minimum time delay with full channel model3

3 μs 500 ns

Maximum time delay with full channel model3

167 μs 1.400 ms

Time delay increment for full channel model3

4 ns 1 ns

Minimum channel coherence time 100 ms 5 μs

Maximum channel coherence time Infinity Infinity

Minimum channel delay spread 0 μs 0 μs

Maximum channel delay spread 10 μs 500 μs

Time resolvable multipath components

@ 100 MHz IBW, Max digital delay, Full 1 20

1 The term “link” refers to the digital signal processing chain, excluding analog RF hardware. It is presumed that the propagation model will be implemented in digital hardware. As a result, specifying dynamic range in terms of number of digital bits seems desirable. However, dynamic range is affected not only by the number of bits utilized, but also how those bits are implemented (floating-point, block floating-point, fixed point, etc.). Therefore, overall dynamic range will be specified in decibels.

2 It is presumed that a simple channel model will consist of only free-space attenuation due to range, and will omit all other channel effects such as multipath. Alternatively, the digital signal processing path will be omitted from the end-to-end signal processing chain, and will only consist of the analog RF front-end.A possible implementation of a simple channel model with delays is an analog attenuation matrix with fiber optic lines of various lengths.

3 It is presumed that a full channel model will consist of a full-mesh with all channel effects enabled, including attenuation, delay, fading, and multipath effects. Alternatively, the end-to-end delay will be composed of the sum of the delays from both the digital signal processing path and the analog RF front-end.

mesh

Time resolvable multipath components

@ 20 MHz IBW, Max digital delay, Full mesh

5 200

3.1.15. The channel emulator shall support the analog RF threshold specifications stated in Table 3.

Table 3: Analog RF Threshold Specifications

Minimum tunable frequency 10 MHz 1 MHz

Maximum tunable frequency 6 GHz 18 GHz

Tuning increment 1 Hz 1 mHz

Dynamic range – Individual Node4 50 dB 90 dB

Instantaneous bandwidth 100 MHz 1 GHz

Tx/Rx duty cycle 100% (full duplex)

100% (full duplex)

Number of wideband receive nodes 1 3

Instantaneous bandwidth of wideband receive nodes

500 MHz 1 GHz

Maximum RF Input Power -20 dBm -20 dBm

Minimum RF Input Power -40 dBm -120 dBm

Maximum RF Output Power -20 dBm -20 dBm

Minimum RF Output Power -120 dBm -120 dBm

4 It is presumed that the dynamic range specified here refers to the analog RF interface of the channel emulator with the software defined radio, including spur-free dynamic range (SFDR), excluding the digital signal processing chain.

It is understood that if the user connects a software defined radio device with worse dynamic range, then the end-to-end dynamic range will be limited by the radio and not the channel emulator.

3.2. Base Requirements for Software Defined Radios

3.2.1. The radios shall be compatible with the GNU Radio SDR framework.

3.2.2. Drivers for the Linux operating system (most recent release of CentOS/Red

Hat at time of delivery) shall be compatible to allow operation with the GNU Radio SDR framework.

3.2.3. The radios shall meet the minimum frequency/power threshold specifications stated in Table 4.

Table 4: Frequency/Power Threshold Specifications

Minimum tunable frequency 10 MHz 1 MHz

Maximum tunable frequency 6 GHz 18 GHz

Tuning increment 100 Hz 1 Hz

Time to tune to random channel 10 ms 1 ms

Spur free dynamic range (100 MHz IBW) 60 dBFS 90 dBFS

Instantaneous bandwidth (IBW) 100 MHz 1 GHz

Phase noise @ 1 kHz offset -80 dBc -90 dBc

Tx/Rx duty cycle 100% (full duplex) 100% (full duplex)

Maximum RF Input Power -20 dBm -20 dBm

Maximum RF Output Power 10 dBm 30 dBm

3.2.4. The radios shall allow phase calibration and alignment to support direction finding and vendor shall provide the calibration algorithm.

3.2.5. The radios shall be enclosed in RF enclosures as specific in Section 3.3.

3.2.6. The radios shall support 10 Gbps as well as 1 Gbps connections for connecting to external digital signal processors.

3.2.7. The radios shall support integration of a Global Positioning System (GPS) disciplined oven controlled crystal oscillator in order to provide, at a minimum, 50 ns timing accuracy.

3.2.8. The radios shall support configurable/removable/replaceable RF downconverter/upconverter such that the RF is mixed to baseband.

3.2.9. The radios shall support full duplex RF operation (i.e. transmit and receive on simultaneously on each node).

3.2.10. The radios shall be fully compatible and integrated with the channel emulator/RF matrix and the RF enclosures.

3.2.11. The radios shall be connected to networked power switches to enable power cycling over the network.

3.3. Base Requirements for RF Enclosures

3.3.1. The test bed shall include 24 RF enclosures capable of fully supporting the

RF ranges for the transceivers specified in Section 3.2

3.3.2. The RF enclosures shall support a minimum isolation of 80 dB across the supported frequency range of the test bed.

3.3.3. The RF enclosures shall have feed through connections that meet the threshold requirements of Table 5.

Table 5: RF Enclosure Feed Through Connections

Connector Threshold Objective

SMA - Female bulkhead1,2 4 6

N - Female bulkhead1,2 1 2

USB 2.0/1.12 1 1

10 GbE SFP+4,5 2 2

10/100/1000 MbE5 1 1

DB15 - 100 pF1,6 0 1 6 pole DC terminal block 1 1 6 pole AC terminal block 1 1

1 All ports shall have dust covers 2 Shall support frequency range of 1 MHz to 18 GHz 3 Shall have ability to switch whether type A and type B connections are inside or outside of enclosure at installed location 4 The implementation of this data link is left to the vendor's discretion. The data link implementation shall be compatible with the Ettus X310. Suggested implementation is use bulkhead to pass multimode fiber through and include appropriate converters to SFP+. The solution used shall be compatible with stock drivers most recent stable version of CentOS/Red Hat Linux at time of delivery and with Intel X710 Quad Port 10Gb Direct Attach SFP+ Converged Network Adapter 5 10 GbE feedthroughs can be reused for 10/100/1000 MbE port. Simultaneous operation of 10 GbE SFP+ and 10/100/1000 MbE is not required.

6 DB-15 port shall be compatible with communication with Ettus X310 General Purpose Input/output (GPIO) port

3.3.4. The RF enclosures shall include a power strip with at least 4 outlets mounted on the inside of the enclosure.

3.3.5. All of the RF enclosures shall be large enough to fit, at a minimum, a single

Ettus Research USRP X310 software defined radio.

3.3.6. The enclosures shall provide adequate cooling to allow a single Ettus

Research X310 to operate for 48 hours without overheating.

3.3.7. The enclosures shall be protected from dust entering the case.

3.3.8. Four (4) of the enclosures shall be large enough to fit an average sized 17-inch laptop (Width: 17 inches, Height: 11 inches, Depth: 12 inches).

3.3.8.1. The larger four (4) enclosures shall contain feed through connections that simultaneously support the connections in 3.3.3.

3.3.8.2. In addition, they shall support the simultaneous operation of an additional port for VGA display.

3.4. Base Requirements For Wideband RF Receiver

3.4.1. Provide a minimum of one wideband receiver that meets the threshold specifications on Table 6.

Table 6: Wideband Receiver Threshold Specifications

Minimum tunable frequency 10 MHz 1 MHz

Maximum tunable frequency 6 GHz 18 GHz

Tuning increment 100 Hz 1 Hz

Time to tune to random channel 10 ms 1 ms

Spur free dynamic range (100 MHz IBW) 70 dBFS 90 dBFS

Instantaneous bandwidth (IBW) 500 MHz 1 GHz

Phase noise @ 1 kHz offset -80 dBc -90 dBc

Rx duty cycle 100% (full duplex) 100% (full duplex)

Maximum RF Input Power -20 dBm -20 dBm

3.5. Rack Requirements

3.5.1. The racks and/or shelves containing equipment shall fit in a location designated by the government and meet all applicable safety requirements

3.5.2. The Contractor is responsible for measuring the location of the designated area.

However, the approximate size of the designated area is: Width: 8 feet, Length: 4 feet, Height: 9.67 feet

3.6. Cable Requirements

3.6.1. The Contractor shall provide digital data cables from the RF shielded enclosures for all USB and network ports present on the feedthrough plate of the enclosure

3.6.1.1. The USB cables shall operate at USB 2.0 speeds

3.6.1.2. The 10 GbE cables must terminate in an SFP+ connector and if

10GBASE-T is used, cables shall be of type Cat-6a

3.6.1.3. The 10/100/1000 MbE cable must be of type Cat-6a

3.7. Option Requirements

This section describes the optional specifications for the associated deliverable that may or may not be exercised at the discretion of NRL.

3.7.1. Expand channel emulator to a minimum of 32 nodes, full mesh, while still meeting all base requirements. Required accessories (e.g. shielded enclosures, RF cables) should also expanded to support 32 nodes

3.7.2. Meet some combination of the objective requirements in 3.3.3.

3.7.3. Meet some combination of the objective requirements in 3.2.3.

3.7.4. Provide and install GPS simulators that provide the analog RF signal to all nodes (24 nodes under base requirements, 32 nodes if option 3.4.1 is exercised).

4. Verification

The government will conduct an Acceptance Test at NRL in Washington, DC to verify that performance meets or exceeds the Threshold or Proposed value (whichever is closest to the Objective). Requirements will be verified as follows:

NRL will perform a fit check to verify that all components meet the mechanical specifications.

NRL will measure the isolation of the fully assembled repeater to verify that the isolation from the transmitter to the receiver meets the isolation specification.

NRL will perform a power test of all components in the transmitter to verify that the components meet the power handling specification.

NRL will perform a visual inspection to verify that the mechanical attachments and connections of the test-bed are adequate for planned operations.

5. Packaging

This section is not applicable to this specification.