802.11s Physical Rates ========================= .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are physical rates in 802.11s?** Physical rates refer to the data transmission speeds supported by the wireless physical layer in mesh networks. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11s define new physical rates?** No, 802.11s uses physical rates defined by base 802.11 standards like 802.11a/b/g/n/ac. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How do physical rates affect mesh performance?** Higher physical rates improve throughput and reduce latency in mesh data transmissions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What modulation schemes are used for physical rates?** Modulation schemes such as DSSS, OFDM, and MIMO techniques from base standards are used. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can physical rates adapt dynamically in 802.11s?** Yes, mesh points dynamically select rates based on link quality and environmental conditions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What role do physical rates play in mesh routing?** They influence path selection by affecting link throughput and reliability in routing decisions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are physical rates consistent across all mesh links?** No, physical rates may vary per link depending on distance, interference, and device capability. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does 802.11s handle rate adaptation?** It leverages base standard rate adaptation algorithms to optimize transmission rates per link. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Is there a minimum physical rate requirement in 802.11s?** No strict minimum, but practical communication depends on sufficient rate for control and data frames. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Do physical rates impact mesh network scalability?** Yes, better physical rates improve capacity, enabling larger mesh deployments. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can physical rates vary with different 802.11s hardware?** Yes, different hardware supports different maximum physical rates based on chipset and antennas. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How do interference and environment affect physical rates?** Interference can reduce link quality, causing devices to drop to lower physical rates. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are physical rates fixed for management frames in 802.11s?** Management frames often use robust lower rates to ensure delivery reliability. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11s support multiple frequency bands?** Yes, physical rates vary depending on whether 2.4 GHz or 5 GHz bands are used. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does physical rate selection impact power consumption?** Higher rates generally reduce transmission time but may increase power during active transmissions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are physical rates related to channel bandwidth?** Yes, wider channels (e.g., 40 MHz) can support higher physical rates than narrower ones. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How do mesh devices negotiate physical rates?** Rate negotiation occurs implicitly via link quality assessments during communication. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can physical rates affect latency in mesh networks?** Yes, higher rates typically reduce transmission delays, lowering overall latency. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What happens if physical rate drops too low on a mesh link?** Mesh may reroute traffic or experience degraded throughput and increased retransmissions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`physical_rates in 802.11r ` * :ref:`Reference links ` .. _physical_rates_s_step4: .. tab-set:: .. tab-item:: physical_rates in 802.11s ========== === ==== =========== ============ =========== ================ ========= ============ =========== ========== ====== Modulation BW Tsc FSP=BW/Tsc Tdata=1/FSP GI=Tdata/4 Symbol=Tdata+GI 1/Symbol Bits/Symbol Code rate Usable sc Rate ========== === ==== =========== ============ =========== ================ ========= ============ =========== ========== ====== BPSK 5 64 78.125 12.8 3.2 16 0.0625 1 1/2 48 1.5 BPSK 5 64 78.125 12.8 3.2 16 0.0625 1 3/4 48 2.25 QPSK 5 64 78.125 12.8 3.2 16 0.0625 2 1/2 48 3 QPSK 5 64 78.125 12.8 3.2 16 0.0625 2 3/4 48 4.5 16-QAM 5 64 78.125 12.8 3.2 16 0.0625 4 1/2 48 6 16-QAM 5 64 78.125 12.8 3.2 16 0.0625 4 3/4 48 9 64-QAM 5 64 78.125 12.8 3.2 16 0.0625 6 2/3 48 12 64-QAM 5 64 78.125 12.8 3.2 16 0.0625 6 3/4 48 13.5 BPSK 10 64 156.25 6.4 1.6 8 0.125 1 1/2 48 3 BPSK 10 64 156.25 6.4 1.6 8 0.125 1 3/4 48 4.5 QPSK 10 64 156.25 6.4 1.6 8 0.125 2 1/2 48 6 QPSK 10 64 156.25 6.4 1.6 8 0.125 2 3/4 48 9 16-QAM 10 64 156.25 6.4 1.6 8 0.125 4 1/2 48 12 16-QAM 10 64 156.25 6.4 1.6 8 0.125 4 3/4 48 18 64-QAM 10 64 156.25 6.4 1.6 8 0.125 6 2/3 48 24 64-QAM 10 64 156.25 6.4 1.6 8 0.125 6 3/4 48 27 BPSK 20 64 312.5 3.2 0.8 4 0.25 1 1/2 48 6 BPSK 20 64 312.5 3.2 0.8 4 0.25 1 3/4 48 9 QPSK 20 64 312.5 3.2 0.8 4 0.25 2 1/2 48 12 QPSK 20 64 312.5 3.2 0.8 4 0.25 2 3/4 48 18 16-QAM 20 64 312.5 3.2 0.8 4 0.25 4 1/2 48 24 16-QAM 20 64 312.5 3.2 0.8 4 0.25 4 3/4 48 36 64-QAM 20 64 312.5 3.2 0.8 4 0.25 6 2/3 48 48 64-QAM 20 64 312.5 3.2 0.8 4 0.25 6 3/4 48 54 64-QAM 20 64 312.5 3.2 0.8 4 0.25 6 5/6 48 57.6 ========== === ==== =========== ============ =========== ================ ========= ============ =========== ========== ====== .. _physical_rates_s_step17: .. tab-set:: .. tab-item:: Reference links * Reference links