List of PPDUs Supported in 802.11an
What is a PPDU in IEEE 802.11an?
PPDU stands for Physical Protocol Data Unit, the unit of data exchanged at the physical layer.
What are the main components of the 802.11an PPDU?
The preamble, SIGNAL field, and the data payload.
What is the function of the preamble in PPDU?
It provides synchronization, channel estimation, and allows the receiver to detect the start of a frame.
How does the SIGNAL field in PPDU work?
It carries information about the data rate, length, and modulation scheme used for the payload.
What modulation technique does 802.11an use for PPDU?
Orthogonal Frequency Division Multiplexing (OFDM).
How does 802.11an support multiple data rates in PPDU?
By varying the modulation and coding schemes indicated in the SIGNAL field.
What is the significance of the tail bits in the PPDU?
Tail bits are used to terminate the convolutional encoder and ensure proper decoding.
How is error detection handled in PPDU?
Through CRC (Cyclic Redundancy Check) included in the MAC frame payload.
What role does interleaving play in the PPDU?
Interleaving distributes bits to minimize the effect of burst errors during transmission.
Does the PPDU structure differ between 802.11a and 802.11an?
The basic PPDU structure is similar but 802.11an includes enhancements for improved performance.
How does the preamble length affect PPDU performance?
Longer preambles improve reliability but add overhead, affecting throughput.
Can PPDU support aggregation of multiple frames?
Yes, frame aggregation is supported to increase efficiency.
How is synchronization achieved between transmitter and receiver in PPDU?
Via the preamble and training sequences in the PPDU.
What is the maximum PPDU size in 802.11an?
The maximum size depends on the MAC frame and physical layer limitations but typically supports large frames through fragmentation.
How does adaptive modulation affect PPDU structure?
It changes modulation parameters dynamically to optimize transmission based on channel conditions.
What is the relationship between PPDU and MAC frame?
The MAC frame is encapsulated within the payload of the PPDU for physical transmission.
How does PPDU handle channel estimation?
Training symbols in the preamble are used for channel estimation.
Are there different PPDU formats in 802.11an?
Yes, variations exist to support different rates, bandwidths, and MIMO configurations.
How does PPDU contribute to overall wireless communication efficiency?
By structuring data transmission with synchronization, error correction, and rate adaptation, PPDU maximizes throughput and reliability.
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