List of PPDUs Supported in 802.11ag
What is a PPDU in IEEE 802.11a/g?
A PPDU is the Physical Layer Protocol Data Unit, the complete packet transmitted over the wireless medium.
What are the main components of an 802.11a/g PPDU?
A PPDU consists of a preamble, a header, and a data payload.
What is the purpose of the preamble in a PPDU?
It allows the receiver to synchronize timing and frequency and prepare for data decoding.
How many preamble types are there in 802.11a/g?
The standard defines a short and a long preamble, with different lengths and complexity.
What modulation does 802.11a/g use for the PPDU?
Orthogonal Frequency Division Multiplexing (OFDM) is used for modulating the PPDU.
What is the PLCP header in the PPDU?
The Physical Layer Convergence Protocol header contains rate, length, and parity information for decoding.
How is the data payload encoded in the PPDU?
Data is encoded using OFDM subcarriers, modulation schemes, and convolutional coding.
What determines the length of a PPDU?
The length depends on the size of the MAC frame and the physical data rate selected.
Can PPDUs have variable length?
Yes, PPDUs vary in length according to the frame size and transmission rate.
What is the symbol duration in an 802.11a/g PPDU?
The OFDM symbol duration is 4 microseconds, including a 0.8 microsecond guard interval.
How does the receiver decode a PPDU?
The receiver synchronizes with the preamble, reads the PLCP header, then demodulates the data payload.
What error detection is used in PPDUs?
The MAC frame includes a CRC for error detection, and convolutional coding helps error correction.
How are acknowledgments related to PPDUs?
Acknowledgment frames are sent as separate PPDUs to confirm successful data reception.
Can multiple PPDUs be aggregated?
802.11a/g does not support frame aggregation; each PPDU carries a single MAC frame.
What is the role of the service field in the PPDU?
The service field contains bits reserved for future use and to help with convolutional decoder initialization.
How does modulation affect PPDU structure?
Modulation schemes (BPSK, QPSK, 16-QAM, 64-QAM) determine bits per symbol in the data payload.
Are there differences in PPDU format between 802.11a and 802.11g?
The PPDU format is largely the same; 802.11g adds backward compatibility with 802.11b.
How do PPDUs affect interoperability?
Standardized PPDU formats ensure devices from different vendors can communicate successfully.
Can firmware updates impact PPDU handling?
Yes, updates can optimize timing, decoding algorithms, and error handling related to PPDUs.
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