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Published 20 hours ago • verified publisher icon xieyaxiongfly

How CSI is calculated at Rx from HT-LTF preamble field

Open sayaz opened this issue 7 years ago • 2 comments

Hi, What I have understood from the 802.11n standard is that the Tx is sending NDP (HT sounding) to the Rx (explicit case). The preamble portion of HT sounding frame has a field (HT-LTF) that contains OFDM training symbols (+/-1) which are actually calculated at the Rx side to estimate CSI.

Can you please explain in brief, how this is being actually calculated at the Rx end to create the feedback matrix? Or any link/book you have that can help me to understand this?

sayaz avatar Feb 20 '18 00:02 sayaz

1, The content of HT-LTF is known to both sides.

2, We assume the transmitted LTF is the same as the theoretical one.

3, The LTF received by receiver is different from the theoretical one.

4, The difference between the LTF sent out by sender (or theoretical one) and the LTF received by receiver is the CSI.

I think the HT-LTF of the preamble is not “calculated” at the RX side. It is received by the RX side.

From: Ayaz Mahmud [mailto:[email protected]] Sent: Tuesday, 20 February, 2018 8:40 AM To: xieyaxiongfly/Atheros-CSI-Tool [email protected] Cc: Subscribed [email protected] Subject: [xieyaxiongfly/Atheros-CSI-Tool] How CSI is calculated at Rx from HT-LTF preamble field (#21)

Hi, What I have understood from the 802.11n standard is that the Tx is sending NDP (HT sounding) to the Rx (explicit case). The preamble portion of HT sounding frame has a field (HT-LTF) that contains OFDM training symbols (+/-1) which are actually calculated at the Rx side to estimate CSI.

Can you please explain in brief, how this is being actually calculated at the Rx end to create the feedback matrix? Or any link/book you have that can help me to understand this?

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xieyaxiongfly avatar Feb 20 '18 01:02 xieyaxiongfly

Hi,

Do you know if I can have access the HT-LTF symbols with your tool? Or where is this HT-LTF defined?

sayaz avatar Sep 19 '18 19:09 sayaz