WARP OFDM Reference Design

The WARP OFDM Reference Design implements a wired-wireless bridge, creating a link between two PCs using a wireless connection between two WARP nodes in place of an Ethernet cable. This link allows the PCs to communicate as if they were connected directly via Ethernet.

This design demonstrates the full MAC/PHY capabilities of WARP. All processing (hardware control, signal processing, MAC protocol) is executed in real-time by each WARP node. PCs are used only to generate/capture Ethernet packets for demonstration purposes; they are not involved in any wireless processing.

The most recent version is OFDM Reference Design v12.1 (view the change log).

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  • Two SISO or MIMO WARP nodes
  • Two PCs with Ethernet interfaces
  • OFDM Reference Design programming file or XPS project

WARP Hardware Setup

You will need two WARP nodes to test this reference design. Each node should have an antenna connected to the radio in daughtercard slot #2. Each node's Ethernet port should be connected to a PC, either directly or via a switch. The two WARP nodes should not be connected to the same Ethernet switch.

The two nodes will be programmed by the same bit file, but they must be uniquely identified to allow the wireless MAC layer to properly address each node. The FPGA board's DIP switch is used to identify each node. One board should have its DIP switch set to all zeros (0000); the other should be set to 0001. See the figure below for the proper settings.

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When you download the reference design to a WARP node, the FPGA board's seven-segment dipslay will show the node's ID, either 0 or 1.

Computer Setup

The WARP wired-wireless bridge allows the PC connected to a WARP node to communicate with the other PC as if they were connected directly via Ethernet. In order to communicate something useful, the two PCs must have their IP addresses configured manually. We suggest the following IP settings:

  • PC 1 IP Address:
  • PC 2 IP Address:
  • Subnet mask (both PCs):

Technically, any pair of IP addresses in the same subnet will work.

Running the Reference Design

If you want to test the design as-is, use the file '/implementation/download.bit' from the ZIP file.

Configure both WARP nodes using the refence design bitstream. You can download the bitstream directly via iMPACT using the FPGA board's built-in USB JTAG programming circuit, an external JTAG cable or using just a CompactFlash card.

Once both WARP nodes are configured, you should be able to ping each PC from the other. You can then run any IP-based networking application between the PCs. We suggest using VLC to stream video from one PC to the other. We have written a brief tutorial on setting up VLC. You can see this exact demo running in our demo videos.

Reference Design Files

The full OFDM Reference Design is available for download. The ZIP file below contains the full XPS project for the OFDM reference design, including both the hardware and software designs.

This design integrates the various hardware, PHY and MAC cores and code we have built. The individual cores and source files are also available in the WARP repository.

Modifying the Reference Design

In order to modify the XPS project provided above, you will need to re-build the hardware project on your PC. Unfortunately, this is required even if you don't make any changes (XPS is not very good about creating portable projects). After re-building the hardware, you can iterate on software changes quickly. The hardware build usually lasts around 40 minutes on a fast (2x 3GHz) machine with lots (4GB) of RAM. It will take considerably longer on slow/low memory machines.

After building the project locally, you will need to generate a linker script for each software project you wish to use. In XPS, choose Software->Generate Linker Script. Make sure your script settings match those shown below. It is critical that no code sections be assigned to the memory block xps_bram_if_cntlr_2.

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Old Reference Designs

OFDM Reference Design v12.0

OFDM Reference Design v11.2

OFDM Reference Design v11.1

OFDM Reference Design v11

OFDM Reference Design v10

OFDM Reference Design v09

OFDM Reference Design v08

OFDM Reference Design v07

OFDM Reference Design v03

OFDM Reference Design v02

Last modified 13 years ago Last modified on Sep 26, 2009, 3:48:07 PM