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Hi, I was told there is warpmac_enableMimoMode() function. However I could not find it. Instead there is warpphy_enableMimoMode(). I put it into warpphy_init().
It looks like the new function takes effect. But the connection between 2 nodes could not be established as described in reference design v07. The Tx may be sending data, but with only Radio #2 working (green LED blinking sparsely), and Radio #3 not working (yellow LED not lighten up).
The radio cards on the Rx behave similarly except that the green LED on the radio #2 is not even observably blinking. However I did observe the USER LEDs #3 and #4 on the Rx change occasionally, which could be a sign of corrupted packets (???).
Can you please verify if that is the right way to activate MIMO mode? Thanks.
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Please keep in mind the OFDM reference design is built to demonstrate a SISO OFDM link between WARP boards. The PHY supports 2x2 spatial multiplexing, but this mode is not nearly as well tested as the default SISO configuration.
That said, you have to make a few more changes to the code to enable MIMO mode.
In warpmac.c / warpmac_sendOfdm(), the second argument to warpphy_pktTx() should be activeRadio (instead of FIRST_RADIO). This will enable the Tx/Rx modes of both radio boards instead of just the one in slot 2.
Also in warpmac_sendOfdm(), change sisoMode = 1 to 0. This flag is used to compute the number of OFDM symbol periods in each packet, a parameter the Tx PHY requires.
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We modified the code to enable MIMO mode, as instructed. After powering up, yellow D3 lightened up on the radio boards in slot 2 only. After we pushed the reset button (SW8), yellow D3 lightened up on the radio boards in both slot 2 and slot 3.
We then used iperf to send the packets. During the transmission, green D4 of the radio boards in slot 2 and 3 of the transmitter were blinking fast.
However, on the receiver side, only the User Leds (D11, D12) on the FPGA board were alternating fast. Does this mean that most of the packets were corrupted? If yes, do you know what is the cause and how we can fix it?
We have another doubt. As we modified warpmac_sendOfdm() only as you instructed, we are not sure if the receiver was treating the packets as MIMO packets. Do we need to modify some other functions to make the receiver behave correctly? Thanks.
Last edited by DQ A (2008-Feb-07 17:37:51)
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Hi,
We did as you instructed on the new reference design v08, and it is still no good. Is there some parameters we should change on the receiving side of the code? Thanks,
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As I mentioned above, the reference designs aren't built/tested in MIMO mode. I'll need to go back and try it myself...
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hi
we were not able to test ofdm in mimo mode. we made the changes in warpphy.c. But the two radio boards when tested seperately in siso mode are working fine.
Could you please suggest the changes needed in source code orelse is there any reference design(full xps projectfile) with mimo mode?
Thanks
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You need to provide much more detail about what you tried, what you changed and what you observed. Like, what reference design are you using? What code changes did you make? Are any good packets getting through? Are headers getting through? Also, please recognize the posts above are nearly 18 months old; the OFDM reference design has changed significantly in that time. The WARPMAC function warpmac_enableMimoMode() should work in the latest designs without having to modify other code.
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hi
We are using reference design 12.1. We have made thae following changes to enable mimo mode
warpmac_enableMimoMode() in the csma.c file in the main fumction in place of warpphy_setSISOantenna(currentAnt)
But we are not able to ping from one board to another after these changes.
Thanks
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