MIMO NI | Alldatasheet

Document overview

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Technical content

This document explains how to use the MIMO Application Framework with a modular hardware system consisting of multiple universal software radio peripheral (USRP) devices in a multiple input, multiple output (MIMO) configuration.

Contents

development environments (ADEs). Table 1. MIMO Base Station (BS) and Multi-Antenna Mobile Station (MS) Parts List0F 1 This is not a complete list of required hardware. For a complete list, contact your local sales representative.

2.4 GHz and 5 GHz Dual

8 GB RAM Upgrade for

Table 2. Single Antenna MS Part List3F 2 Also referred to as a Clock Distribution Accessory (CDA). 3 Also referred to as a Cabled PXI Express Switch Box (CPS). 4 This is not a complete list of required hardware. For a complete list please contact your local sales representative.

4 | ni.com | MIMO Prototyping System Getting Started Guide USRP-2950/2952/2953/2954/2974 1 USRP RIO Laptop Connectivity Kit (ExpressCard and Cable) 1 Laptop with ExpressCard Slot 1

2.4 GHz and 5 GHz Dual Band Vertical Antenna 2

Electromagnetic Compatibility Guidelines The individual components of this product were tested and comply with the regulatory requirements and limits for electromagnetic compatibility (EMC) stated in their respective specifications. These requirements and limits provide reasonable protection against harmful interference when the product is operated in the intended operational electromagnetic environment. However, the system as a whole has not been through EMC testing as a unit and the users are expected to use it in a way that complies to all regulations in their region. To minimize interference with radio and television reception and prevent unacceptable performance degradation, install and use this product in strict accordance with the instructions in the product documentation. Furthermore, any changes or modifications to the product not expressly approved by National Instruments could void your authority to operate it under your local regulatory rules. Note: In the United States (per FCC 47 CFR), Class A equipment is intended for use in commercial, light- industrial, and heavy-industrial locations. In Europe, Canada, Australia, and New Zealand (per CISPR 11), Class A equipment is intended for use only in heavy-industrial locations. Notice: The MIMO System is intended for use only indoors test environment as test and measurement equipment. This product is intended for professional use only. Notice: To ensure the specified EMC performance, operate this product only with shielded cables and accessories. Notice: To ensure the specified EMC performance, operate this product only with cables less than 3 meters in length. General system components The MIMO Application Framework supports system setups consisting of the following components:

  • One multi-antenna BS
  • One or more MSs Both single antenna and multi-antenna MSs are supported. Single Antenna Mobile Station The least complex system component supported by the MIMO Application Framework is the single antenna MS. A single antenna MS represents a handset or another wireless device with single input,

functionality (data piping) is split between FPGA and host. Figure 1. Typical Single Antenna MS Setup with Laptop and USRP Device supports BS configurations with between two and 128 antennas. Table 3. Multi-Antenna BS Configurations

5 The GPSDO is important because it provides improved clock accuracy exploited by the single antenna MS

extensions. The USRP-2950/2952/2953/2954/2955/2974 devices contain a GPSDO. 6 This is not a complete list of required hardware. For a complete list, contact your local sales representative.

Figure 2. BS

  1. The CDA-2990 provides both clock and time synchronization by amplifying and distributing

directly from the PXIe-6674T module.

matched-length cables (shipped with the USRP device). subsystem are distributed among the eight USRP devices in the subsystem through a CDA-2990 devices. connections diagram for each USRP subsystem. cables from the PXIe-6674T module to each USRP device) must be equal for each channel. Figure 3. Connections in Each USRP Subsystem antenna BS (with a potentially reduced number of USRP devices).

Table 4. MIMO BS Parts

1 PXIe-8135 PXIe-8135 PXIe-8135 PXIe-8135

2 PXIe-8384 PXIe-8384 PXIe-8384 PXIe-8384

3 PXIe-8384 PXIe-8384 PXIe-8384 Slot blocker

4 PXIe-8384 PXIe-8384 Slot blocker Slot blocker

5 PXIe-8384 PXIe-8384 Slot blocker Slot blocker

6 PXIe-7976 (FLEX4) Slot blocker Slot blocker Slot blocker

7 PXIe-7976 (FLEX3) Slot blocker Slot blocker Slot blocker

8 PXIe-7976 (FLEX2) PXIe-7976 (FLEX2) Slot blocker Slot blocker

9 PXIe-7976 (FLEX1) PXIe-7976 (FLEX1) PXIe-7976 (FLEX1) PXIe-7976 (FLEX1)

10 PXIe-6674T PXIe-6674T PXIe-6674T PXIe-6674T

11 Slot blocker Slot blocker Slot blocker Slot blocker

12 PXIe-8384 Slot blocker Slot blocker Slot blocker

13 PXIe-8384 Slot blocker Slot blocker Slot blocker

14 PXIe-8384 Slot blocker Slot blocker Slot blocker

15 PXIe-8384 Slot blocker Slot blocker Slot blocker

16 Slot blocker Slot blocker Slot blocker Slot blocker

17 Slot blocker Slot blocker Slot blocker Slot blocker

18 PXIe-7976 (FLEX0) PXIe-7976 (FLEX0) PXIe-7976 (FLEX0) PXIe-7976 (FLEX0)

Refer to the “Connection Diagrams” section for detailed connection diagrams. Table 5. Cable Connections within USRP Subsystems

Table 6. Cable Connections between the Master CDA and the CDAs in USRP Subsystems

01 PPS OUT 1 EXT PPS

02 PPS OUT 2 EXT PPS

03 PPS OUT 3 EXT PPS

04 PPS OUT 4 EXT PPS

05 PPS OUT 5 EXT PPS

06 PPS OUT 6 EXT PPS

07 PPS OUT 7 EXT PPS

08 PPS OUT 8 EXT PPS

Table 7. Cable Connections between the PXI and the CPS in USRP subsystems

Table 8. Cable Connections between PXIe-6674T and Master CDA Table 9. Cable Connection between USRP Subsystem #1 and the PXIe-6674T (Master Trigger) Figure 12. 16-Antenna MIMO System Connection Diagram

Figure 13. 32-Antenna MIMO System Connection Diagram

Figure 14. 64-Antenna MIMO System Connection Diagram

Figure 15. 128-Antenna MIMO System Connection Diagram download page for the LabVIEW Communications MIMO Application Framework. Communications System Design Suite is required to permanently activate the software.

signal propagation, resulting in poor system operation.

  • Connect the power supplies to multiple power strips and enabling the power strips sequentially.
  • Connect the power supplies one-by-one.
  • Power the system on and off using the power button of each USRP device rather than a master switch.
  • Use multiple wall outlets on different circuits. Base Station and Multi-Antenna Mobile Station 1. Power on all the USRP subsystems. 2. Power on the PXI controller. Single Antenna Mobile Station 1. Power on the USRP device. 2. Power on the computer (laptop, PC, or PXI chassis) to which the USRP is connected. Software Hardware Naming For the BS setups as well as the multi-antenna MS setups, the MIMO Application Framework expects the hardware system components to be named according to a specific naming scheme, as shown in the table below. Use NI MAX, or System Designer in LabVIEW Communications, to change the hardware aliases for the listed hardware component if necessary. The MIMO Application Framework is designed to support three different naming schemes, that is, three different sets of hardware aliases. The naming schemes can be selected in the following top-level host nodes in the MIMO Application Framework through the USRP Naming Scheme control:
  • Base Station Host
  • Multi Antenna Mobile Station Host

Table 10. Naming Schemes and Hardware Aliases

20 | ni.com | MIMO Prototyping System Getting Started Guide Device USRP Naming Scheme Aliases USRP CPS(1-8) Port(1-8)Dev1 Default naming scheme. CPS1Port1Dev1, CPS1Port2Dev1, …, CPS1Port8Dev1, CPS2Port1Dev1, CPS2Port2Dev1, …, CPS2Port8Dev1, and so on. The aliases above are the default names created by MAX for a CPS switch box-based standard HW setup. USRP (01-64) USRP01, USRP02, USRP03, …, USRP64 Understanding the Components of this Sample Project The design project is comprised of LabVIEW host code and LabVIEW FPGA code. The related folder structure and components of the project are described in the following subsections. The description covers the Design project, which comprises all FPGA and host software parts. There is a Simulation project limited to the code that is necessary to run simulation tests. Create a New Design Project Instance To create a new instance of the MIMO Application Framework, launch LabVIEW Communications System Design Suite by selecting NI LabVIEW NXG 4.0 from the Start menu. From the Project Templates on the launched Project tab, select Application Frameworks » MIMO Design <Version> to launch the project. Folder Structure The following files and folders are created inside the specified folder: MIMO Design <Version>.lvproject This project file contains reference to all nodes and targets. Base Station Host.gcomp This contains the top-level host node of the BS7F 8. The BS implementation realizes a downlink (DL) transmitter (TX) and an uplink (UL) receiver (RX) and can communicate with up to twelve single antenna MSs or a multi-antenna MS with up to twelve antennas. The BS host interfaces with multiple FlexRIO FPGA modules, which serve as MIMO processor and bit processor units, and with multiple USRP devices, which serve as RRHs. The bitfiles are built from the following corresponding FPGA top-level nodes:

  • MIMO Processor FPGA.gcomp: This is the MIMO Processor top-level FPGA node where the largest part of the in-phase/quadrature (I/Q) baseband signal processing is executed. A MIMO Processor bitfile can be configured to work for up to 32, 64 or 128 antennas. Each bitfile handles either all, half, or a fourth of all subcarriers per orthogonal frequency division multiplexing (OFDM) symbol. Refer to the “System Overview” section for more details. 8 Also referred to as the Evolved Node B (eNodeB or eNB), especially in the context of LTE.

MIMO Prototyping System Getting Started Guide | © National Instruments | 21

  • Bit Processor FPGA.gcomp: This is the Bit Processor top-level FPGA node where the TX and RX bit processing are executed. The TX packet generator as well as the RX packet validator are also realized in the bit processor.
  • RRH FPGA.gcomp: This is the RRH top-level FPGA node where the OFDM modulation and demodulation as well as the interfacing with the RF is performed. Refer to the “System Overview” section for more details. Multi Antenna Mobile Station Host.gcomp This contains the top-level host node of the multi-antenna MS8F 9. The multi-antenna MS implementation realizes an UL TX and a DL RX, which support an even number of TX/RX antennas between 2 and 12. The general hardware-software partitioning is the same as for a (16-antenna) BS. The multi-antenna MS host interfaces with two FlexRIO FPGA modules, which serve as MIMO processor and as bit processor, and with multiple USRP devices, which serve as RRHs. The related bitfiles are built from the same FPGA top-level nodes which are used for the BS:
  • MIMO Processor FPGA.gcomp
  • Bit Processor FPGA.gcomp
  • RRH FPGA.gcomp. Single Antenna Mobile Station Host.gcomp This contains the top-level host node of the single antenna MS 9 implementation. It is built to control two single antenna MSs in parallel. This host node interfaces with one USRP device where the main part of the DL RX and UL TX signal processing for two parallel MSs is implemented. The corresponding bitfile is built from the following top-level FPGA node:
  • Single Antenna Mobile Station FPGA.gcomp: This is the single antenna MS top-level FPGA node. It implements two MSs (“MS 0” and “MS 1”), each with a DL RX and UL TX. Note: As stated above, the described nodes for the single antenna MS always implement two MS in parallel. There aren’t special nodes implementing only one single antenna MS since the MS instances can be deactivate separately. This can be done by setting the layer assignment controls MS 0 Layer or MS 1 Layer in the top-level host node Single Antenna Mobile Station Host.gcomp to value OFF. Builds This folder contains the precompiled bitfiles. The FlexRIO modules used as MIMO processors (needed for BSs and multi-antenna MSs) are loaded with MIMO Processor bitfiles. Which bitfile is used specifically depends on which of the following system configurations is used:
  • MIMO Processor 32 Antennas.lvbitx: Used for BSs with the number of antennas configured between two and 32. It is used also for the multi-antenna MS.
  • MIMO Processor 64 Antennas.lvbitx: Used for BSs with (up to) 64 antennas. 9 Also referred to as the User Equipment (UE), especially in the context of LTE.
  • MIMO Processor 128 Antennas.lvbitx: Used for BSs with (up to) 128 antennas. For the bit processing in BSs and multi-antenna MSs, a single FlexRIO module is loaded with the Bit Processor bitfile:
  • Bit Processor.lvbitx: Used for BS and multi-antenna MS bit processing. It works with all BS configurations. The USRP devices that serve as RRHs for BSs or multi-antenna MSs are loaded with the following bitfiles:

Table 11. USRP Devices as RRHs

  • Single Antenna Mobile Station.lvbitx: Used for USRO RIO devices with 120 MHz or 160 MHz BW.
  • Single Antenna Mobile Station 40 MHz.lvbitx: Used for USRO RIO devices with 40 MHz BW. Common Contains generic host and FPGA nodes that are shared between different application frameworks, such as mathematical functions, type conversions, and so on. Link Simulator Contains the Link Simulator which simulates the UL and DL TX chains on the host. MIMO Contains host and FPGA nodes and type definitions that were specifically designed for the MIMO Application Framework. It is organized in components that are used on FPGA or Host, or that are Shared between Host and FPGA. USRP RIO Contains host and FPGA nodes of the USRP drivers. The nodes are organized into components for FPGA SubVIs, Host SubVIs and Shared items. The MIMO USRP components for FPGA and USRP contain files from the streaming sample project that were modified for the MIMO Application Framework. The contained nodes can be used for all supported USRP target devices.

MIMO Prototyping System Getting Started Guide | © National Instruments | 23 Note: This folder was taken from the NI-USRP Multi-device Synchronized Simple Streaming sample project. Deploy The Single Antenna Mobile Station and Multi Antenna Mobile Station can be deployed to a system that does not have LabVIEW Communications System Design Suite installed. 1. Set all configuration parameters that cannot be changed at runtime to their desired value and mark them as default value. For Single Antenna Mobile Station, this affects the following parameters: RIO Device, USRP Bandwidth, Sync Mode, Frame Schedule, and RF Frequency. For Multi Antenna Mobile Station, this affects the following parameters: USRP Naming Scheme, USRP Bandwidth, Antenna Configuration, Sync Mode, Frame Schedule, and RF Frequency. 2. Save the VI and change to the corresponding component. 3. In the Document tab of the component, click Build. Wait in the Build queue tab for the build to complete. To find the final executable, right-click on the build and select Locate item in Windows Explorer. 4. Copy the executable to the destination machine. NI automates LabVIEW NXG and LabVIEW Communications System Design Suite installation using NI Package Manager. Visit ni.com/r/NIPMDownload to download NI Package Manager. Refer to the NI Package Manager Manual for more information about installing, removing, and upgrading NI software using NI Package Manager. Once the Package Manager is available on the destination machine install the following products:

  • LabVIEW Runtime Engine 5.3.2 or later
  • NI-USRP 19.5 or later Note: When installing NI-USRP, ensure that the NI-USRP RIO Runtime dependency is also installed. Start the mobile station by double click on the executable copied to the destination machine. Create a New Simulation Project Instance To create a new instance of the MIMO Application Framework simulation, launch LabVIEW Communications System Design Suite by selecting NI LabVIEW NXG 4.0 from the Start menu. From the Project Templates on the launched Project tab, select Application Frameworks » MIMO Simulation <Version> to launch the project. Folder Structure The folder structure follows the MIMO Design project. There are also two additional components which contains the Host based testbenches (Testbenches.gcomp) as well as the FPGA wrappers (Testbenches FPGA.gcomp).

24 | ni.com | MIMO Prototyping System Getting Started Guide System Overview System Features The MIMO Application Framework offers a ready-to-run design for MIMO prototyping. It comprises a fully-functional PHY for bi-directional transmission as well as basic MAC layer elements. The main features are highlighted below.

  • Multi-user MIMO transmission between one BS with up to 128 antennas and up to 12 single antenna MSs.
  • Single-user MIMO transmission between one BS with up to 128 antennas and one MS with up to 12 antennas.
  • Bi-directional, OFDM-based time-division duplex (TDD) transmission using 20 MHz signal BW.
  • Fully re-configurable Long-Term Evolution (LTE)-like radio frame structure.
  • Number of MSs or the number of spatial layers per multi-antenna MS can be changed on runtime. The system adapts automatically.
  • Scalable number of antennas (multi-antenna MS: between 2 and 12; BS: between 2 and 128). Interfaces and configuration adapt automatically.
  • FPGA based real time signal processing such as modulation, over-the-air synchronization, MIMO equalization and MIMO precoding.
  • Linear multi-user MIMO precoding and equalization for up to 128 × 12 antenna systems. Options: Minimum mean squared error (MMSE), zero-forcing (ZF), and maximum-ratio combining (MRC). Multi-user MIMO precoding (at the BS) is channel reciprocity based.
  • Automatic channel reciprocity calibration for all radio units at the BS.
  • Automatic gain control (AGC) at the BS and MS.
  • Variable modulation schemes ranging from 4-quadrature amplitude modulation (QAM) to 256- QAM
  • Basic MAC functionality supports packet-based user data transmission in DL and UL to enable data streaming applications, such as video transmission. Note: Visit ni.com/r/MIMOAppFWManual to access the LabVIEW Communications MIMO Application Framework Manual for more information about the MIMO Application Framework design. System Components Base Station The BS components are comprised of the DL TX and the UL RX paths.

Figure 16. Block Diagram of the BS (TX and RX Chain) The different BS components and their tasks are described below. receives and transmits payload data using the user datagram protocol (UDP).

  • Data Handling: Reads received data from FPGA and stores received payload to queues.
  • Data Source: Realizes the data source for the DL payload data. It provides the following three operation modes: o UDP: Payload data is read from the configured UDP ports. o PN data: Random pseudo-noise (PN) payload data is generated on the host. o OFF: No payload data is provided from the host. MAC TX will generate zero padding data if needed.
  • Data Sink: Realizes the data sink for the received UL payload data. It provides the following two operation modes: o UDP: The received data is sent as UDP packets to the configured remote address and ports. o OFF: The received data will be discarded. Bit Processor: Is the central processing unit for TX and RX bit processing. The main components of this module are the following: MIMO Processor 0 … 3 BS HOST Data Source TX Packet Generator Router 1 TX IQ Chain Router 2 & 3 RX Packet Validator Router 0 RX IQ Chain Router 0 & 1 Data Handling MAC TXMAC RX Bit Processor TX Bit ProcessingRX Bit Processing RF RRH 0 (RRH Combiner) OFDM TX OFDM RXRouter 0 RRH 1 RRH 2 RRH 3 RRH 4 RRH 5 RRH 6 RX P2P Subsystem 0 Subsystem 7 TX P2P

100 Mbytes/s

26 | ni.com | MIMO Prototyping System Getting Started Guide

  • TX Packet Generator: Generates the packets based on the MAC packet structure. Visit ni.com/r/MIMOAppFWManual to access the LabVIEW Communications MIMO Application Framework Manual for more information.
  • RX Packet Validator: Performs frame validation by means of frame check sequence (FCS), which contains an IEEE 32-bit cyclic redundancy code (CRC).
  • TX Bit Processing: Responsible for TX bit processing including data scrambling, TX bit grouping, modulation and data reordering.
  • RX Bit Processing: Responsible for RX bit processing including data reordering, demapping, packing, and descrambling.
  • Router 0 & 1: Used for dynamic data routing. Every router has its own routing program, which is written from the host depending on the given system configuration. Router 0 is used to route the RX data from MIMO processors to the RX bit processing chain. Router 1 is used to route the transmit data from the TX bit processing chain to the MIMO processors. MIMO Processors: The central processing units for the frequency-domain TX and RX I/Q Processing. Depending on the system configuration, a MIMO processor processes all, half, or a fourth of the subcarriers OFDM symbol.
  • TX I/Q Chain: Includes modules such as Precoding, Stream Combiner, and so on.
  • RX I/Q Chain: Performs the MIMO channel estimation and equalization.
  • Routers: Used for dynamic data routing. Every router has its own routing program, which is written from the host depending on the given system configuration. o Router 0 & 1: Used to route RX data from RRH subsystems to the MIMO processor(s). o Router 2 & 3: Used to route TX data from the MIMO processor(s) to the RRH subsystems. RRH Subsystem: The RRHs contain the analog-to-digital converters (ADC) and digital-to-analog converters (DAC). They handle the transformation from time-domain to frequency-domain and vice versa. Multiple RRHs (two to eight) build a subsystem. A BS can consist of one to eight subsystems.
  • RRH Splitter (last RRH in subsystem): Receives the transmit data from the MIMO processors, distributes it to the TX chains of all other RRHs in the subsystem, one after the other, and finally to its own TX chain.
  • RRH Combiner (first RRH in subsystem): Accumulates the received data from its own RX chain, followed by the RX chains of all other RRHs in a subsystem, one after the other, and sends it to the MIMO processors.
  • OFDM Only RRH: Named for the other RRHs in a subsystem excluding the first and last RRH. o The RX data is transferred to the RRH Combiner through the corresponding peer-to-peer (P2P) stream. o The TX data is given from the RRH Splitter through the corresponding P2P stream.
  • OFDM TX and OFDM RX: Each RRH contains OFDM modulation and OFDM demodulation.
  • RF: In the TX path, it performs DUC, RF impairments correction, and writes the TX data to the RF. In the RX path, it reads the RX data from the RF, performs DDC and performs RF impairments correction. Note: If there are two antennas in the BS, only the RRH combiner is used.

The following figure shows the block diagram of the single antenna MS. Figure 17. Block Diagram of the Single Antenna MS (TX and RX Chain) Host: Configures the FPGA and displays the system status. Interfaces with the MS bitfile.

  • Data Handling: Reads received data from FPGA and stores received payload to queues.
  • Data Source: Realizes the data source for the DL payload data. It provides three operation modes o UDP: Payload data is read from the configured UDP ports. It is used in the UL Data field of each slot, which is then encoded and modulated as an UL signal by the UL TX (UL TX PHY). o PN data: Random PN payload data is generated on the host. o OFF: No payload data is provided from the host. MAC TX will generate zero padding data if needed.
  • Data Sink: Realizes the data sink for the received UL payload data. It provides the following two operation modes: o UDP: The received data is sent as UDP packets to the configured remote address and ports. o OFF: The received data will be discarded. FPGA: Contains the MAC and PHY modules for the UL and the DL.
  • MAC TX: A simple MAC implementation which adds a header containing the number of payload bytes. The header is followed by the payload in bytes and the remaining bytes are filled with padding bytes. The 32-bit CRC is then added.
  • MAC RX: Packets validator and payload extraction.
  • UL TX PHY: The PHY of the UL TX creates the UL signal based on the configured frame structure as digital baseband I/Q data. This includes resource mapping, pilot generation, and OFDM modulation.
  • Sync: Estimates the radio frame start and synchronization parameters. The primary synchronization signal (PSS) is used for frame detection, and frequency and timing offset Data Source M AC TX UL TX PHY RF FPGA Digital Baseband Up Conversion Down ConversionDL RX PHYM AC RX Trigger Source TDD Switching Host Sync Data Handling Data Sink

an external trigger signal provided from the BS.

  • DL RX PHY: The PHY of the DL RX demodulates the DL signal. This includes OFDM demodulation, channel estimation and equalization.
  • Up Conversion: Performs digital up conversion (from the LTE sampling rate of 30.72 MS/s to 120 MS/s or 200 MS/s, depending on the USRP model), performs RF impairments correction, and writes the resulting TX samples to the RF interface.
  • Down Conversion: Reads RX samples from the RF interface, performs digital down conversion (from 120 MS/s or 200 MS/s, depending on the USRP model, to the LTE sampling rate of 30.72 MS/s), and performs RF impairments correction.
  • TDD Switching: Responsible for TX and RX activation based on the frame schedule. Multi-Antenna Mobile Station The multi-antenna MS extends the single antenna MS by adding the capability to transmit and receive multiple spatial streams using multiple antennas. It has the same hardware configuration of 16-antenna BS. However, the number of antennas should be even number up to 12. The block diagram is shown in

Figure 18. It is similar to that of the BS shown in Figure 16, Block Diagram of the BS (TX and RX Chain),

  • UL TX: The signal processing is identical to the DL TX signal processing in the BS. The number of active TX antennas is controlled by the number of activated layers. The number of active layers can be selected by the user on the front panel of the top-level host node. Each active layer is mapped to one TX antenna, where the layers with the lowest index is mapped to TX antenna 0, the layer with the second lowest index to TX antenna 1, and so on.
  • DL RX: The RX implementation including channel estimation, equalizer Computation, and linear equalization blocks is similar to BS UL RX implementation. Only a synchronization and tracking unit is added to the RX chain. The synchronization is identical to the single antenna MS. A single RX antenna is used for synchronization as well as for tracking. The user can select from the front panel of Multi Antenna Mobile Station Host.gvi either RF0 or RF1 of the RRH combiner, the first RRH in the system, to be the synchronization reference. The synchronization results are then transferred in a daisy chain to the other RRHs as it is shown in the following figure. Note: The DL RX processing always runs for all RX antennas.

Figure 18. Block Diagram of the Multi-Antenna MS (TX and RX Chain) Ensure you meet the hardware and software requirements before trying to run the host code.

  1. Launch LabVIEW Communications System Design Suite by selecting NI LabVIEW NXG 4.0 from
  2. From the Project Templates on the launched Project tab, select Application Frameworks, then

select MIMO Design to launch the project.

  1. Within that project, open Base Station Host.gvi (located in Base Station Host.gcomp). The front

panel of this node is shown in Figure 19.

  1. Set the following configurations in Base Station Host.gvi:

MAX, as described in Table 10, Naming Schemes and Hardware Aliases. b. Set the USRP Bandwidth Model depending on the hardware model of your USRP devices. c. Set the System Configuration control to the required configuration. in dBm and RX gain in dB that are available in the RRH tab or keep the default values.

  1. Run the Base Station Host.gvi by clicking the run button ( ).

o If successful, the Base Station Active indicator lights. for transmission over-the-air using an antenna.

Figure 19. Front Panel of BS (Configuration Tab)

  1. Launch LabVIEW Communications System Design Suite by selecting NI LabVIEW NXG 4.0 from
  2. From the Project Templates on the launched Project tab, select Application Frameworks, then

select MIMO Design to launch the project.

  1. (USRP-2974 only) Ensure you are mapped to the RT target.

a. Open SystemDesigner in Design view. d. If Status is Not matched, select the … button. device. You are now mapped to the correct device.

  1. Within that project, open Single Antenna Mobile Station Host.gvi located in Single Antenna

Mobile Station.gcomp. The front panel of this node is shown in Figure 20.

  1. (USRP-2974 only) Select the RT target by selecting the Single Antenna Mobile Station RT Host

instead of the default target (PXI Controller).

  1. Set the following configurations in Single Antenna Mobile Station Host.gvi.

a. Configure the RIO identifier in the RIO Device control.

MIMO Prototyping System Getting Started Guide | © National Instruments | 31

  • Use MAX to configure the hardware alias of the USRP device that you want to use as MS.
  • (USRP-2974 only) Set the RIO Device to RIO0 instead of the default name of USRPUE. b. Set the USRP Bandwidth Model depending on the hardware model of your USRP devices. c. Select the synchronization mode using the Sync Mode control. d. Set the RF Frequency per the BS.10F e. Set the AGC mode to auto or manual. If the AGC is configured to manual, set the TX power in dBm and RX gain in dB that are available in the AGC Settings and Status tab. f. Set the MS ID of both MSs (MS 0 UE ID and MS 1 UE ID). Each MS ID has its modulation scheme as shown in Figure 20. 5. Run Single Antenna Mobile Station Host.gvi by clicking the run button ( ).
  • If successful, the Mobile Stations Ready indicator lights.
  • If an error is indicated, go to the Error tab to check the error message. Use MAX to check if the USRP device is configured with the correct hardware alias. If you want to transmit and receive with more than two single antenna MSs (one MS host), you have two options: 1. Use different host computers. For example, use one laptop with one USRP device connected to it per MS host. 2. Use the same host computer (for example, a PXI chassis) with multiple USRP device connected to it. To run multiple MS hosts, you must duplicate Single Antenna Mobile Station Host.gvi. When using multiple MS hosts, the above configurations should be repeated for each MS host. Please make sure to select the correct RIO Device each time and to choose unique UE IDs. When using the same UE ID twice the BS will not be able to decode the UL because it receives a mixed signal with the same UL pilots and the same UL data scrambling sequence. 11 Consider local laws if you are transmitting over-the-air. USRP and USRP RIO devices are not approved or licensed for transmission over-the-air using an antenna.

Figure 20. Front Panel of Single Antenna MS (Configuration Tab)

  1. Launch LabVIEW Communications System Design Suite by selecting NI LabVIEW NXG 4.0 from
  2. From the Project Templates on the launched Project tab, select Application Frameworks, then

select MIMO Design to launch the project.

  1. Within that project, open Multi Antenna Mobile Station Host.gvi located in Multi Antenna

Mobile Station.gcomp. The front panel of this node is shown in Figure 21.

  1. Set the following configurations in Multi Antenna Mobile Station Host.gvi:

MAX as shown in Table 10, Naming Schemes and Hardware Aliases. b. Set the USRP Bandwidth Model depending on the hardware model of your USRP devices. c. Set the System Configuration control to the required configuration. in dBm and RX gain in dB that are available in the AGC tab or keep the default values. f. Assign the active layers that are available in the Layer mapping tab.

  1. Run the Multi Antenna Mobile Station Host.gvi by clicking the run button ( ).
  • If successful, the Mobile Station Active indicator lights.
  • If an error is indicated, go to the Error tab to check the error message. Here you will also see if an error occurred during the initialization of the timing module, the MIMO processors, the Bit processor or the RRHs. The first failing element tells which module 12 Consider local laws if you are transmitting over-the-air. USRP and USRP RIO devices are not approved or licensed for transmission over-the-air using an antenna.

with the correct hardware alias. same UL pilots and the same UL data scrambling sequence. Figure 21. Front Panel of Multi-Antenna MS (MIMO Configuration Tab) Complete the following steps to verify that the system is running.

  1. Select the Frame Schedule Table in the Configuration tab on the Base Station Host.gvi to find

the modulation scheme of the selected MSs.

  1. For UL investigation, select the UL MIMO Processor tab on the Base Station Host.gvi, and verify

quadrature phase-shift keying (QPSK) modulation and MS 1 should have 16 QAM modulation. Furthermore, select the UL Data tab and verify the UL throughput.

  1. Based on the MS mode either single antenna MS or multi-antenna MS, the DL investigation can
  • Single Antenna Mobile Station Host.gvi: Select the DL Advanced Information tab and verify that the presented RX constellations match the corresponding modulation schemes according to the Frame Schedule Table. Furthermore, select the DL Information tab and verify the DL throughput.
  • Multi Antenna Mobile Station Host.gvi: Select the DL MIMO Processor tab and verify that the presented RX constellations match the corresponding modulation schemes

34 | ni.com | MIMO Prototyping System Getting Started Guide according to the Frame Schedule Table. Furthermore, select the DL Data tab and verify the DL throughput. 4. Refine Timing synchronization: If the constellation of the measured data at the BS is rotated, the user should refine the timing synchronization. The Signal Delay graphical indication on the RRH tab shows the estimated time delay in LTE samples of all MSs or of all layers in case of using multi-antenna MS. This graphical representation can be used to calibrate the time delay by using the MS TX Delay control on the Configuration tab of Single Antenna Mobile Station Host.gvi and that on the System Configuration tab of Multi Antenna Mobile Station Host.gvi. Running Video Streaming The MIMO Application Framework implements a basic MAC functionality which allows for bi-directional packet-based data exchange of user-defined payload data. Figures 22 and 23 show simple example use cases where user-defined data is transferred in the UL using a multi-antenna MS or multiple single antenna MSs, respectively. The user-data is received at the MS from a data source in form of UDP packets and send out at the BS to a data sink also in form of UDP packets. Any program capable of transmitting UDP data can serve as a data source. Similarly, any program capable of receiving UDP data can serve as a data sink. If you use a video streaming application as a data source and a video player as a data sink, the MIMO Application Framework can be used for video streaming. The following section describes video streaming using the VLC media player, which is available at www.videolan.org. Start Video Stream at the Transmitter (MS) The MS host acting as an UL transmitter receives UDP packets from the video streaming application and utilizes the MIMO Application Framework to transmit the data frames. 1. Create a new project as described in Running the LabVIEW Host Code section. 2. For single antenna MS: Open the top-level host node of the MS, Single Antenna Mobile Station Host.gvi, set the correct RIO identifier in the RIO device parameter, and then set UL Data Source on the Configuration tab to UDP. 3. For multi-antenna MS: Open the top-level host node of the MS, Multi Antenna Mobile Station Host.gvi, set the USRP naming scheme and the system configuration (even number and up to 12 antennas), and then set UL Data Source on the System Configuration tab to UDP. 4. For single antenna MS, user can configure the initial value of UL Data UDP Port of the first MS. The UDP port of the second MS on Single Antenna Mobile Station Host.gvi is equal to the initial value plus one. 5. Run the LabVIEW host node by clicking the run button ( ). 6. Start cmd.exe and change the directory to the VLC installation directory. 7. Start the VLC application as a streaming client with the following command: vlc.exe --repeat "PATH_TO_VIDEO_FILE” :sout=#std{access=udp{ttl=1},mux=ts,dst=@:UDP_PORT_TX} where PATH_TO_VIDEO_FILE should be replaced with the location of the video that should be used. The value of UDP_PORT_TX is 50.000, which is the default UDP Receive Port for MS ID 0. The default UDP receive port can be changed using the Initial UL Data UDP Port control on

Multi Antenna Mobile Station Host.gvi. using multiple single antenna MSs, each MS host opens two UDP ports for the two RF chains. The UL UDP Data Ports indicator shows the used ports. value—for example 53,000—and so on. Figure 22. Data Streaming from a Multi-Antenna MS to the BS Using UDP

Figure 23. Data Streaming from Multiple Single Antenna MSs to the BS Using UDP frames and pass them through UDP to the video player.

  1. Create a new project as described in “Running the LabVIEW Host Code” section.
  2. Open the top-level host node of the BS, Base Station Host.gvi, and then switch to System

Configuration tab and set UL Data Sink to UDP.

  1. Run the LabVIEW host node by clicking the run button ( ).
  2. Start cmd.exe and change the directory to the VLC installation directory.

MIMO Prototyping System Getting Started Guide | © National Instruments | 37 5. Start the VLC application as a streaming client with the following command: vlc.exe udp://@:UDP_PORT_RX The value of UDP_PORT_RX is 61.000, which is the default UDP Transmit Port. The default value of UDP_PORT_RX can be changed using the Initial UL Data UDP Port control on Configuration tab. The UDP_PORT_RX values is derived as an Initial UL Data UDP Port plus the MS identity. Description of Controls and Indicators Description of Controls and Indicators on the BS Host Front Panel This section describes all controls, graphs and indicators which are placed on the BS host front panel. BS Basic Controls and Indicators Several controls and indicators are placed outside the main tab control of Base Station Host.gvi as shown in Figure 19, Front Panel of BS (Configuration Tab). The following tables list the corresponding controls and indicators. Table 12. BS Host – Main Panel Controls

Description

No Determines the naming scheme of the USRP devices which are loaded with the RRH bitfiles. The enumeration contains the following values:

  • CPS(1-8)Port(1-8)Dev1
  • PXI(2-5)Slot(2-18)Port1Dev1
  • USRP(01-64) USRP Bandwidth No Determines the BW of the used USRP devices. The enumeration contains the following values:
  • 160 MHz
  • 120 MHz
  • 40 MHz Antenna Configuration No Determines the number of antennas in the system. The typedef of antenna configuration can be modified to have any even number between 2 and 128. Frame Schedule No Determines the frame schedule to use. RF Frequency No The center frequency for radio transmission and reception.12F AGC Mode Yes Selects the AGC mode: manual or auto. If the AGC is manual, go to the RRH tab to adjust the TX Power and RX gain. Const. of Layers Yes Selects the layer identity for the constellation plot below. Set to sweep to sweep through the layers over time. If the Filter Inactive Layers control is active, the sweeping will include only the active layers. Filter Inactive Layers Yes Filters inactive layers in several graphs, for example, the constellation plots. 13 Consider local laws if you are transmitting over-the-air. USRP and USRP RIO devices are not approved or licensed for transmission over-the-air using an antenna.

38 | ni.com | MIMO Prototyping System Getting Started Guide Control Uses Runtime Yes Selects the displaying rate type of UL Throughput [Mbit/s] and DL Transmission Rate [Mbit/s] indicators:

  • PHY: Shows the packet data rate.
  • MAC: Shows the payload throughput. If the DL Data Source and UL Data Sink controls under System Configuration tab are set to UDP without running the video streaming, the displayed DL Transmission Rate and UL Throughput are zeros if the Rate Display Selection is set to MAC.

Table 13. BS Host – Main Panel Indicators and Graphs the gain value is coerced by the capabilities of the device. control or of all layers in sweep. UL Throughput [MBit/s] Numerical display showing the total UL throughput in Mbit/s. Numerical display showing the total DL transmission rate in Mbit/s. Base Station Active A Boolean indicator that indicates the BS is ready. A Boolean indicator that lights up if an error occurred. Station Host.gvi as shown in Figure 19, Front Panel of BS (Configuration Tab). Table 14. BS Host - Controls on System Configuration Tab No Sets the required parameters of reciprocity calibration process. Those are the Reference Radios and the Waiting Time before Calibration.

MIMO Prototyping System Getting Started Guide | © National Instruments | 39 Control Uses Runtime Reference Radios No Selects the reference radios for reciprocity calibration. NI recommends that you have at least one reference radio per subsystem. The first RRH of each subsystem is selected by default. Waiting Time before Calibration (in minutes) No Sets the waiting time after bit files download to the FPGAs. Recommended: 9 minutes. PN Data Packet Size Yes Size of packets in PN data transmission mode. There will be always the same packet transmitted over all configured layers. PN Packets per Seconds Yes Number of packets transmitted in PN mode per seconds. DL Data Source Yes Has three options:

  • Off: No data is transmitted in DL.
  • UDP: Received UDP packets are transmitted to the corresponding layer in DL.
  • PN Data: A random packet is transmitted at PN packets per second rate on all active layers. Initial DL Data UDP Port No An offset to start opening UDP ports for UDP packet reception. The default UDP Transmit Port is 60.000. For each layer, the corresponding UDP port value is 60.000 plus the layer identity. UL Data Remote Address Yes IP address that the packets received from UL are sent to. UL Data Sink Yes Has two options:
  • Off: Received data is discarded.
  • UDP: Received frames are forwarded to the configured UDP address and port. Initial UL Data UDP Port No Offset to start opening UDP ports for UDP packet transmission. The default UDP Receiver Port is 61.000. For each layer, the corresponding UDP port value is 61.000 plus the layer identity.

Table 15. BS Host - Indicators on System Configuration Tab RRHs Shows the RIO aliases of active USRP devices per subsystem. MIMO Processors Shows the addresses of active FlexRIO modules for I/Q processing. Bit Processor Shows the address of active FlexRIO module for bit processing. Timing Module Shows the address of Timing Module RIO card. reference radio reduced to the available radios. MS, single UDP port is used. antenna MS, single UDP port is used.

40 | ni.com | MIMO Prototyping System Getting Started Guide BS Control and Indicators on MIMO Configuration Tab The following tables list the controls and indicators placed on the MIMO Configuration tab of Base Station Host.gvi as shown in Figure 24. Table 16. BS Host - Controls on MIMO Configuration Tab Yes Selects the layer identity manually. One per UE Yes If it is true, the UE-ID equals the layer number. Otherwise, choose from the following options:

  • All layers can be assigned to single UE-ID for multi-antenna MS.
  • The user-to-layer mapping can be custom-configured for multi single antenna MSs. All for UE Yes If true, all layers will be assigned to single UE-ID given by the numerical control beside All for UE control. Otherwise, it is a custom configuration using the Boolean array under One per UE and All for UE controls. Boolean Matrix Yes For custom configuration, click to enable or disable layers by clicking the matrix element to map UE (row) to layer (column). Use One per UE or All for UE buttons for default settings. The system prevents assigning a layer to multiple UEs and enforces at least on assigned layer. MIMO Equalization Algorithm Yes Configures the algorithm that is used for equalization. The enumeration contains the following values: MMSE, MRC, and ZF. Sigma Yes Selects the scaling factor that is used in the modified Gram-Schmidt QR decomposition (MGS-QRD) algorithm of the MMSE channel estimator.

Table 17. BS Host - Indicators on MIMO Configuration Tab Shows the active layers that has been detected in the BS. Schedule Table indicator is controlled by the Frame Schedule control. rank. The effective number of spatial streams can then be identified.

leads to a small block error rate (BLER). Figure 24. Front Panel of BS (MIMO Configuration Tab) Table 18. BS Host - Control on RRH Tab Yes Sets the BS RF TX power in dBm. Yes Sets the BS RF RX gain in dB. instance, if the number of spatial layers is increased.

Table 19. BS Host – Graphs and Indicators on RRH Tab Power value is coerced to the allowed range. Power value is coerced to the allowed range. frame (calculated on OFDM symbol basis) over all antennas. control that is located on the above side of the figure. Figure 25. Front Panel of BS (RRH Tab) that are placed on the UL MIMO Processor tab of Base Station Host.gvi as shown in Figure 26.

Table 20. BS Host - Controls on UL MIMO Processor Tab Table 21. BS Host - Indicators on UL MIMO Processor Tab control located on the right side under the Stop button. Figure 26. Front Panel of BS (UL MIMO Processor Tab) tables show the corresponding numerical control and indicators, respectively. Table 22. BS Host - Control on UL MIMO Processor (Host) Tab equalization and display the constellations.

Figure 28. Front Panel of BS (DL Data Tab) Table 25. BS Host - Indicators on UL Data Tab for all layers. In addition, the BLER of all layers is presented. BLER Graph Graphical indicator showing the BLER of all layers.

Figure 29. Front Panel of BS (UL Data Tab) Host.gvi as shown in Figure 30. Table 26. BS Host - Control on UL Channel Tab Table 27. BS Host - Indicators on UL Channel Tab signal strength in dBFS for all layers versus all antennas of BS. frequency responses in dBFS of all layers. responses is in dBFS while the time delay is in terms of LTE samples. impulse response in dBFS of all layers as an intensity figure.

48 | ni.com | MIMO Prototyping System Getting Started Guide Indicator Description RX Overflows Numerical indicator that shows overflows in the first-in-first out memory buffer (FIFO) that connects the USRP RX loop, which reads from the ADC and performs digital down-conversion, and the RX I/Q processing loop, which performs OFDM demodulation. Overflows can occur when the samples are not processed fast enough either in the RX I/Q processing chain or on the MIMO Processors. Another possibility is too high traffic on the PCI-Express bus which stalls the P2P streams. The values should be 0 if the system is in normal operation. 14 Fixed-point overflow Boolean indicator that shows fixed-point overflows in the I/Q processing chain. The TX power levels and RX gains should be configured so that no fixed-point overflows occur. RRH Router 0 Number of samples processed per second by RRH Router 0. For RRH 0 (RRH Combiner), the number should be 1.26 × 107 multiplied by the number of RRHs in the subsystem. For MIMO Processor 0 to MIMO Processor 3 Router 0 and Router Numeric indicators displaying the number of samples processed by router 0 and router 1 per second. The value should be 1.008 × 108. Bit Processor Router 0 Numeric indicator displaying the number of samples processed by router 0 per second. The value depends on the selected frame schedule. Overflows in RX Chain RRH USRP RX Overflow Indicates that an overflow occurred on the RRH between RF and baseband clock domain. MIMO Processor Local FIFO Overflow Indicates that an overflow occurred on the MIMO processor when forwarding RX data to the bit processor. Bit Processor Data FIFO Overflow Indicates that an overflow occurred on the bit processor when writing RX data to host. DTP Processor FIFO Underflow Indicates that an underflow occurred during the payload and packet information collection of the data transfer protocol (DTP) payload in a FIFO in the bit processor. This Boolean indicator is true if there is data underflow in any layer’s DTP payload that is collected in a Round-Robin. DTP Processor FIFO Overflow Indicates that an overflow occurred during the payload and packet information collection of the DTP payload in a FIFO in the bit processor. This Boolean indicator is true if there is data overflow in any layer’s DTP payload that is collected in a Round-Robin.

Table 32. BS Host – Indicators on Error Tab Error Displays the resulting error cluster. Error Report Displays resulting error as error report. and, if yes, displays the hardware alias of the timing module. Bit Processor Initialization Indicates if an error occurred during initialization of the bit processor. yes, displays the hardware alias of the first failing element. Figure 33. Front Panel of BS (Error Tab) following tables list the corresponding controls and indicators.

Table 33. Single Antenna MS – Main Panel Controls hardware manager. This control should be configured before running MS.

  • 160 MHz
  • 120 MHz
  • 40 MHz Sync Mode No Selects the MS Synchronization Mode:
  • Over-the-air by using synchronization signal.
  • Using external trigger provided by the BS through the PPS trigger port. Frame Schedule No Determines the frame schedule to use. RF Frequency No Selects a frequency supported by your USRP device as the RF Frequency.14F TX Delay Yes Used to adjust the time delay manually in RF clock cycles of the USRP device. It should be used with the Signal Delay [Samples] figure placed on RRH tab of the BS front panel. MS 0 Layer Yes Selects the MS layer identity from the set {0, …, 11}.15F Selects the MS layer identity to off to deactivate the MS 0. MS 1 Layer Yes Selects the MS layer identity from the set {0, …, 11}.16 Selects the MS layer identity to off to deactivate the MS 1. Rate Display Selection Yes Selects the MS rate of DL Throughput [Mbit/s] and UL Transmission Rate [Mbit/s] indicators:
  • PHY: Shows the packet data rate.
  • MAC: Shows the payload throughput. If the UL Data Source and DL Data Sink controls under System Configuration tab are set to UDP without running the video streaming, the displayed UL Transmission Rate and DL Throughput are zeros if the Rate Display Selection is set to MAC.

Table 34. Single Antenna MS – Indicators on Basic Configurations Mobile Stations Ready If the system started up successfully, it lights. for transmission over-the-air using an antenna. 16 Each MS should be given a different identity. Otherwise they will receive the same data from the BS.

Antenna MS (Configuration Tab). Table 35. Single Antenna MS – Controls on System Configuration Tab Mode control is over-the-air. It can be automatic or MS 0 or MS 1. the same packet transmitted over all configured layers. Yes Number of packets transmitted in PN mode per seconds.

  • UDP: Received UDP packets are transmitted with the corresponding MS in UL.
  • PN Data: A random packet is transmitted at PN packets per second rate on all active MSs. Initial UL Data UDP Port No This UDP port address and the subsequent one are opened for UDP packet reception for both MSs. The default UDP UL Data Port is 50.000. DL Data Remote Address Yes The IP address that the UDP packets received from BS are sent to. DL Data Sink Yes If it is set to UDP, received frames are forwarded to the configured UDP address and port. Initial DL Data UDP Port No This UDP port address and the subsequent one are opened for UDP packet transmission of both MSs. The default UDP DL Data Port is 51.000. Table 36: Single Antenna MS – Indicators on Configuration Tab Indicator Description Frame Schedule Table Shows the OFDM Frame Schedule of all 12 layers. The OFDM symbol types of each MS frame (140 OFDM Symbols) are presented. The OFDM symbol type could be Guard, Sync, DL pilot, DL data, UL pilot, and UL data. In addition, the modulation schemes of all layers are presented, which could be QPSK, 16-QAM, 64-QAM, and 256-QAM. The Frame Schedule Table indicator is controlled by Frame Schedule control. UL Data UDP Ports Shows the value of UDP ports to forward traffic to the BS. DL Data UDP Ports Shows the value of UDP ports to forward traffic from the BS.

Table 37. Single Antenna MS – Controls on AGC/TPC & Synchronization Tab

  • AGC Settings
  • Manual Settings
  • Status AGC Settings Yes Sets the required parameters of RX AGC. AGC Mode Yes Switch between automatic and manual gain control Manual Settings Yes Sets the required parameters of manual AGC mode. RX Gain (manual) Yes Sets the RF RX gain in dB of both MSs in manual mode. TX Power - TPC Yes Sets the required parameters of transmission power control (TPC) in the TX chain. It has three sets of controls and indicators:
  • TPC Settings
  • Manual Settings
  • Status TPC Settings / TPC Mode Yes Switch between automatic and manual transmit power control. TPC Settings / Base Station Configuration The values of the BS configuration must match the settings on the BS. RX Gain Yes Sets the value similar to that of BS RF RX gain in dB. Active Layers Yes Sets the overall number of active UL layers in the system. TX Power Yes Sets the value similar to that of BS RF TX power in dBm. Antennas Yes Sets the number of antenna at the BS. Manual Settings - TX Power Yes Sets the RF TX power in dBm for both MSs in case of manual mode.

Table 38. Single Antenna MS – Indicators on AGC/TPC & Synchronization Tab RX Gain – AGC / Status Shows the status of the RX AGC. Coerced RX Gain The actual used analog RX RF gain in dB for both MSs. Shows the power of the received PSS synchronization signal for both MSs. TX Power – TPC Status Shows the status of the Transmit Power control. (range and resolution limitations) to the configured value.

Boolean indicators corresponding to the Coerced TX Power indicator. Graphical indication showing the timing estimation of the radio frame. Detected figure cannot show that. Figure 34. Front Panel of Single Antenna MS (AGC/TPC & Synchronization Tab) Table 39. Single Antenna MS –Indicators on DL Information Tab received from the RF of MS 0.

received from the RF of MS 1. DL Throughput MS 0 [Mbit/s] Graphical indication showing the DL throughput of MS 0 in Mbit/s. DL PHY MS 0 Numerical display showing the PHY throughput of MS 0 in Mbit/s. DL MAC MS 0 Numerical display showing the MAC throughput of MS 0 in Mbit/s. DL Throughput MS 1 [Mbit/s] Graphical indication showing the DL throughput of MS 1 in Mbit/s. DL PHY MS 1 Numerical display showing the PHY throughput of MS 1 in Mbit/s. DL MAC MS 1 Numerical display showing the MAC throughput of MS 1 in Mbit/s. BLER MS 0 Graphical and numerical indicator showing the BLER of MS 0. BLER MS 1 Graphical and numerical indicator showing the BLER of MS 1. Figure 35. Front Panel of Single Antenna MS (DL Information Tab) Table 40. Single Antenna MS – Indicators on DL Advanced Information Tab Overflow counters for the respective target to host FIFO.

MIMO Prototyping System Getting Started Guide | © National Instruments | 57 Indicator Description RX Const MS 1 Overflow USRP RX Chain Status Numerical and Boolean indicators are used to signal misbehavior within the RX chain. RX IQ Signal Clipped MS 0 Shows if the RX I/Q signal is clipped due to bad level control. RX IQ Signal Clipped MS 1 Shows if the RX I/Q signal is clipped due to bad level control. RX Number of Overflows Number of overflows in RX before baseband processing. RX Overflow Indicates the RX Number of Overflows value if it is different from zero. DTP Handling FIFO Overflow MS 0 Overflow in DTP FIFOs for the respective MS. DTP Handling FIFO Overflow MS 1 Overflow in DTP FIFOs for the respective MS. RX Constellation MS 0 Constellation of RX I/Q samples of MS 0 after equalization. The OFDM symbol to display is changed after each update in a Round- Robin fashion. RX Constellation MS 1 Constellation of RX I/Q samples of MS 1 after equalization. The OFDM symbol to display is changed after each update in a Round- Robin fashion. Channel Frequency Response MS 0 [dB] Graphical representation of the channel amplitude in dB and phase estimated using the pilots. Channel Frequency Response MS 1 [dB] Graphical representation of the channel amplitude in dB and phase estimated using the pilots. SNR (dB) MS 0 and SNR (dB) MS 1 Numerical indicators show the measured SNR (dB) of MS 0 and MS EVM (%) MS 0 and EVM (%) MS Numerical indicators show the measured EVM defined as a percentage of MS 0 and MS 1. The earned value of EVM indicates to the quality of measurements. A small value of EVM (%) leads to a small BLER.

Figure 36. Front Panel of Single Antenna MS (DL Advanced Information Tab) From Figure 37, the indicators on the UL Information tab of the MS are presented in the following table. Table 43. Single Antenna MS – Indicators on UL Information Tab signal transferred to the RF of MS 0. IFFT Output Clipped MS 1 Indicates a numeric overflow after the IFFT of MS 1. signal transferred to the RF of MS 1.

Figure 38. Front Panel of Single Antenna MS (Error Tab) Mobile Station Host.gvi. Most of the controls and indicators are similar to that of the BS. following tables list the presented controls and indicators, respectively. Table 45. Multi-Antenna MS Host – Main Panel Controls

  • CPS(1-8)Port(1-8)Dev1
  • PXI(2-5)Slot(2-18)Port1Dev1
  • USRP(01-64) USRP Bandwidth No Determines the BW of the used USRP devices. The enumeration contains the following values:
  • 160 MHz
  • 120 MHz
  • 40 MHz TX Delay Yes Used to adjust the time delay manually in RF clock cycles of the RRHs. It should be used with the Signal Delay [Samples] figure placed on RRH tab of the BS front panel. By continuously adjusting
  • Over-the-air by using synchronization signal.
  • Using external trigger provided by the BS through PPS trigger port. Frame Schedule No Determines the frame schedule to use. RF Frequency No The center frequency for radio transmission and reception. Const. of Layer Yes Selects the layer identity for the constellation plot below. Set to sweep to sweep through the layers over time. Rate Display Selection Yes Selects the displaying rate type of UL Transmission Rate [Mbit/s] and DL Throughput [Mbit/s] indicators:
  • PHY: Shows the packet data rate.
  • MAC: Shows the payload throughput. If the UL Data Source and DL Data Sink controls under System Configuration tab are set to UDP without running the video streaming, the displayed UL Transmission Rate and DL Throughput are zeros if the Rate Display Selection is set to MAC.

Table 46. Multi-Antenna MS Host – Main Panel Indicators and Graphs control or of all layers in sweep. Numerical display showing the total UL transmission rate in Mbit/s. DL Throughput [MBit/s] Numerical display showing the total DL throughput in Mbit/s. Mobile Station Active Boolean indicator that lights up if the MS is ready. Boolean indicator that lights up if an error occurred. Antenna Mobile Station Host.gvi as shown in Figure 39. Table 47. Multi-Antenna MS Host – Controls on System Configuration Tab same packet transmitted over all configured layers. Yes Number of packets transmitted in PN mode per seconds.

  • Off: No data is transmitted in UL.
  • UDP: Received UDP packets are transmitted with the corresponding MS in UL.
  • PN Data: A random packet is transmitted at PN packets per second rate on all active MSs. UL Data UDP Port No This UDP port address is opened for UDP packet reception. The default UDP UL Data Port is 50.000. DL Data Remote Address Yes The IP address that the UDP packets received from BS are sent to. DL Data Sink Yes If it is set to UDP, received frames are forwarded to the configured UDP address and port. DL Data UDP Port No This UDP port address is opened for UDP packet transmission. The default UDP DL Data Port is 51.000.

Table 48. Multi-Antenna MS Host - Indicators on System Configuration Tab RRHs Shows the RIO aliases of active USRP devices per subsystem. MIMO Processor Shows the addresses of active FlexRIO modules for I/Q Processing. Bit Processor Shows the address of active FlexRIO module for bit processing. Timing Module Shows the address of Timing Module RIO card. Figure 39. Front Panel of Multi-Antenna MS (System Configuration Tab)

Table 49. Multi-Antenna MS Host – Controls on MIMO Configuration Tab Yes Activates the assigned layers to transmit data. of a layer is set to true, the assigned layer will transmit pilots. the following values: MMSE, MRC, and ZF. Table 50. Multi-Antenna MS Host - Indicators on MIMO Configuration Tab Schedule Table indicator is controlled by the Frame Schedule control. rank. The effective number of spatial streams can then be identified. SNR per Layer (dB) A numerical array shows the measured SNR (dB) for all active layers. measurements. A small value of EVM (%) leads to a small BLER. controls and indicators shown.

Table 51. Multi-Antenna MS Host – Controls on AGC Tab RX Gain - AGC Yes Sets the required parameters of AGC in the RX chain.

  • AGC Settings
  • Manual Settings
  • Status AGC Settings Yes Sets the required parameters of RX AGC. AGC Mode Yes Switch between automatic and manual gain control. AGC Target Midpoint Yes Target RX power in digital base band used in AGC mode auto. The optimal value depends on the PAPR of the received signal. Decrease the default setting if the PAPR increases, for instance, if the number of spatial layers is increased. Manual Settings Yes Sets the required parameters of manual AGC mode. Common RX Gain Yes RX Gain value applied to all antennas. RX Gain Mode (Common/Individual) Yes Switch between common RX Gain and gain value per antenna. RX Gains Yes Set gain values per antenna. TX Power - TPC Yes Sets the required parameters of TPC in the TX chain. It has three sets of controls and indicators:
  • TPC Settings
  • Manual Settings
  • Status TPC Settings / TPC Mode Yes Switch between automatic and manual transmit power. TPC Settings /TPC Measurement Mode Yes The measured PSS Symbol Powers at all antennas are used in the TPC in two options:
  • Max: The maximum power is used to derive the TX power.
  • Average: The mean value of all measured powers is used to derive the TX power. TPC Settings / Base Station Configuration Yes The values of the Base Station Configuration must match the settings on the BS. TX Power Yes Sets the value similar to that of BS RF TX power in dBm. RX Gain Yes Sets the value similar to that of BS RF RX gain in dB. Active Layers Yes Sets the number of active layers in the system. Antennas Yes Sets the number of antenna at the BS. Manual Settings Yes Sets the required parameters of manual TPC mode. Common TX Power Yes TX power value applied to all antennas. TX Power Mode (Common/Individual) Yes Switch between common TX Power and TX Power per antenna. TX Power Yes Sets the TX Power value per each antenna manually.

Table 52. Multi-Antenna MS Host – Indicators on AGC/TPC Tab RX Gain – AGC / Status Shows the status of the RX AGC. layers either the AGC Mode is auto or manual. synchronization signal for all layers. TX Power – TPC / Status Shows the status of the TX power. the configured value either TPC is manual or Auto. capabilities (range and resolution limitations) to the configured value. Boolean indicators corresponding to the Coerced TX Power indicator. coerced to the allowed range.

Figure 40. Front Panel of Multi-Antenna MS – AGC/TPC Tab The following tables show the MS controls and indicators that occur on Sync tab as shown in Figure 41. Table 53. Multi-Antenna MS – Controls on Sync Tab of the first RRH in the MS for the synchronization process. provided then to the other RRHs in a daisy chain. on the Amplitude of Received Subcarriers figure. Table 54. Multi-Antenna MS – Indicators on Sync Tab Autodetected PSS Antenna Shows the RF port that has been selected for the synchronization. that while the Signal Detected figure cannot show that. synchronization signal. The graph is updated every second.

CFO [Hz] Graphical indication (below-right) showing the CFO in Hz. Delay control on the Sync tab. Figure 41. Front Panel of Multi-Antenna MS (Sync Tab) the required controls and indicators, respectively. Processor (Host) Tab, list the description of the controls and indicators, respectively.

Host.gvi. The indicators are listed in Table 31, BS Host – Indicators on DL Debug Tab. Figure 43. Front Panel of Multi-Antenna MS (UL Debug Tab) initialization. The indicators are similar to those presented on the Error tab of the Base Station Host.gvi. The indicators are listed in Table 32, BS Host – Indicators on Error Tab.

  • Your hardware devices are connected correctly.
  • The USRP devices are already switched on and connected to the host before the host is switched on. Otherwise the USRP devices may not properly recognized by the host.
  • If any device, such as the USRP device, is switched off, restart the laptop or the PXI system. You can access the known issues list online at ni.com/manuals. Related Information
  • NI USRP and LabVIEW Communications System Design Suite Getting Started Guide
  • IEEE Standards Association: 802.11 Wireless LANs
  • 3GPP TS 36.211 (Physical channels and modulation) Release 10
  • 3GPP TS 36.213 (Physical layer procedure) Release 10

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  • Visit ni.com/r/MIMOAppFWManual to access the LabVIEW Communications MIMO Application Framework Manual.
  • Visit ni.com/r/commsmanual to access the LabVIEW Communications System Design Suite Manual for information about LabVIEW concepts or objects used in this sample project.
  • Use the Context Help window to learn basic information about LabVIEW objects as you move the cursor over each object. To display the Context Help window in LabVIEW, select View»Context Help.