802.11ag Physical Rates
What are physical rates in IEEE 802.11a/g?
Physical rates refer to the data transmission speeds supported by the wireless standard at the physical layer.
How many physical rates does 802.11a/g support?
802.11a/g supports eight standard physical rates from 6 Mbps to 54 Mbps.
Why are multiple physical rates important?
Different rates allow devices to adapt to varying channel conditions and maintain connectivity.
How do devices select a physical rate?
Devices use rate adaptation algorithms based on signal quality, error rates, and interference levels.
Is the physical rate the same as the actual throughput?
No, throughput is usually lower due to protocol overhead, retransmissions, and medium contention.
What is the lowest physical rate in 802.11a/g?
The lowest mandatory rate is 6 Mbps.
What is the highest physical rate in 802.11a/g?
The highest rate is 54 Mbps.
How does signal strength affect physical rates?
Stronger signals allow higher rates; weaker signals force devices to drop to lower rates for reliability.
Are physical rates fixed or dynamic during communication?
They are dynamic; devices can switch rates on-the-fly to optimize performance.
How do environmental factors impact physical rates?
Obstacles, interference, and distance reduce signal quality, often lowering achievable physical rates.
Do all devices support all physical rates?
Most devices support all mandatory rates, but some may omit certain optional rates.
What modulation techniques correspond to physical rates?
Physical rates map to specific modulations like BPSK, QPSK, 16-QAM, and 64-QAM with coding rates.
Can physical rates affect battery life?
Higher rates can transmit data faster, potentially reducing active radio time and saving battery.
What is rate fallback?
A mechanism where devices reduce their physical rate after transmission failures to improve reliability.
How does physical rate influence latency?
Higher physical rates generally reduce transmission time, decreasing latency.
Are physical rates the same in 802.11a and 802.11g?
Yes, both support the same set of OFDM-based physical rates.
How do physical rates relate to channel bandwidth?
802.11a/g uses 20 MHz channels, which support the defined physical rates; wider channels allow higher rates in newer standards.
How do physical rates impact network capacity?
Higher physical rates can increase overall network capacity by reducing airtime per packet.
What role do physical rates play in interoperability?
Devices must support mandatory rates to interoperate properly under the standard.
Can firmware updates change physical rate support?
Yes, vendors may improve rate adaptation or add support for optional rates via updates.
Topics in this section,
In this section, you are going to learn
Terminology
Version Info
setup
Reference links