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wlanHTSTF

Generate HT-STF waveform

Description

example

y = wlanHTSTF(cfg) generates an HT-STF[1] time-domain waveform for HT-mixed format transmissions, given the parameters specified in cfg.

Examples

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Create a wlanHTConfig object with a 40 MHz bandwidth.

cfg = wlanHTConfig('ChannelBandwidth','CBW40');

Generate an HT-STF. The function returns a complex output of 160 samples.

stf = wlanHTSTF(cfg);
size(stf)
ans = 1×2

   160     1

Change the channel bandwidth to 20 MHz and create a new HT-STF.

cfg.ChannelBandwidth = 'CBW20';
stf = wlanHTSTF(cfg);

Verify that the number of samples has been halved due to the bandwidth reduction.

size(stf)
ans = 1×2

    80     1

Input Arguments

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Format configuration, specified as a wlanHTConfig object.

Output Arguments

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HT-STF waveform, returned as an NS-by-NT matrix. NS is the number of samples, and NT is the number of transmit antennas.

Data Types: double
Complex Number Support: Yes

More About

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HT-STF

The high throughput short training field (HT-STF) is located between the HT-SIG and HT-LTF fields of an HT-mixed packet. The HT-STF is 4 μs in length and is used to improve automatic gain control estimation for a MIMO system. For a 20 MHz transmission, the frequency sequence used to construct the HT-STF is identical to that of the L-STF. For a 40 MHz transmission, the upper subcarriers of the HT-STF are constructed from a frequency-shifted and phase-rotated version of the L-STF.

HT-mixed

As described in IEEE Std 802.11™-2012, Section 20.1.4, high throughput mixed (HT-mixed) format packets contain a preamble compatible with IEEE Std 802.11-2012, Section 18 and Section 19 receivers. Non-HT (Section 18 and Section19) STAs can decode the non-HT fields (L-STF, L-LTF, and L-SIG). The remaining preamble fields (HT-SIG, HT-STF, and HT-LTF) are for HT transmission, so the Section 18 and Section 19 STAs cannot decode them. The HT portion of the packet is described in IEEE Std 802.11-2012, Section 20.3.9.4. Support for the HT-mixed format is mandatory.

References

[1] IEEE Std 802.11™-2012 IEEE Standard for Information technology — Telecommunications and information exchange between systems — Local and metropolitan area networks — Specific requirements — Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Introduced in R2015b

[1] IEEE® Std 802.11-2012 Adapted and reprinted with permission from IEEE. Copyright IEEE 2012. All rights reserved.