802.11ah 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 frequency band does 802.11ah use for physical rates?** 802.11ah operates primarily in the sub-1 GHz frequency bands, such as 900 MHz. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the maximum physical data rate supported by 802.11ah?** The maximum data rate of 802.11ah is up to 347 Mbps under ideal conditions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What modulation techniques are used in 802.11ah?** 802.11ah uses OFDM (Orthogonal Frequency Division Multiplexing) with BPSK, QPSK, 16-QAM, and 64-QAM modulations. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does 802.11ah achieve different data rates?** By varying modulation schemes, coding rates, and channel bandwidths. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What channel bandwidths does 802.11ah support?** 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz channel bandwidths. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Why does 802.11ah use narrower channels than traditional Wi-Fi?** Narrower channels improve range and penetration in sub-1 GHz bands, ideal for IoT and sensor networks. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the lowest data rate supported by 802.11ah?** The lowest physical rate is approximately 0.15 Mbps using BPSK modulation with strong coding. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does 802.11ah adapt data rates dynamically?** It uses rate adaptation algorithms that select modulation and coding based on link quality. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the impact of sub-1 GHz operation on physical rates?** Lower frequency bands provide longer range but typically lower maximum data rates compared to 2.4 GHz or 5 GHz bands. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11ah support MIMO technology?** 802.11ah primarily focuses on single-stream transmissions but can support multiple spatial streams in some implementations. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How many subcarriers does 802.11ah OFDM use?** 802.11ah uses 32, 64, or 128 subcarriers depending on the channel bandwidth. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What coding schemes are applied in 802.11ah?** Convolutional coding with various coding rates (e.g., 1/2, 2/3, 3/4) is used for error correction. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How do physical rates affect battery life in 802.11ah devices?** Lower data rates with robust modulation improve range and reduce retransmissions, which can conserve battery life. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are the typical use cases for different physical rates in 802.11ah?** Lower rates suit sensors and IoT devices with low data needs, higher rates support video or firmware updates. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Is 802.11ah data rate affected by interference?** Yes, interference can reduce effective data rates by forcing more robust modulation and retransmissions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does channel bonding affect 802.11ah physical rates?** Channel bonding can combine smaller channels to increase throughput, though it is less common in 802.11ah. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can 802.11ah physical rates support long-range communication?** Yes, especially at lower rates with narrow bandwidths, allowing communication up to 1 km or more. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the role of OFDM in 802.11ah physical rates?** OFDM enables efficient spectrum use and robustness against multipath fading to maintain reliable data rates. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`physical_rates in 802.11a ` * :ref:`Reference links ` .. _physical_rates_ah_step4: .. tab-set:: .. tab-item:: Physical rates in 802.11ah (1, 2, 4, 8, 16 MHz bandwidths) =========== ======== ======== ============ ============= =========== ================== ========= ============ =========== =========== =========== Modulation BW Tsc FSP=BW/Tsc Tdata=1/FSP GI=Tdata/4 Symbol=Tdata+GI 1/Symbol Bits/Symbol Code rate Usable SC Data Rate (kbps) =========== ======== ======== ============ ============= =========== ================== ========= ============ =========== =========== =========== BPSK 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 1 1/2 32 100 BPSK 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 1 3/4 32 150 QPSK 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 2 1/2 32 200 QPSK 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 2 3/4 32 300 16-QAM 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 4 1/2 32 400 16-QAM 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 4 3/4 32 600 64-QAM 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 6 2/3 32 800 64-QAM 1MHz 4kHz 250 µs 4 ms 1 ms 5 ms 200 Hz 6 3/4 32 900 BPSK 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 1 1/2 64 200 BPSK 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 1 3/4 64 300 QPSK 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 2 1/2 64 400 QPSK 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 2 3/4 64 600 16-QAM 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 4 1/2 64 800 16-QAM 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 4 3/4 64 1200 64-QAM 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 6 2/3 64 1600 64-QAM 2MHz 8kHz 125 µs 2 ms 0.5 ms 2.5 ms 400 Hz 6 3/4 64 1800 BPSK 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 1 1/2 128 400 BPSK 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 1 3/4 128 600 QPSK 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 2 1/2 128 800 QPSK 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 2 3/4 128 1200 16-QAM 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 4 1/2 128 1600 16-QAM 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 4 3/4 128 2400 64-QAM 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 6 2/3 128 3200 64-QAM 4MHz 16kHz 62.5 µs 1 ms 0.25 ms 1.25 ms 800 Hz 6 3/4 128 3600 BPSK 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 1 1/2 256 800 BPSK 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 1 3/4 256 1200 QPSK 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 2 1/2 256 1600 QPSK 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 2 3/4 256 2400 16-QAM 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 4 1/2 256 3200 16-QAM 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 4 3/4 256 4800 64-QAM 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 6 2/3 256 6400 64-QAM 8MHz 32kHz 31.25 µs 0.5 ms 0.125 ms 0.625 ms 1600 Hz 6 3/4 256 7200 BPSK 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 1 1/2 512 1600 BPSK 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 1 3/4 512 2400 QPSK 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 2 1/2 512 3200 QPSK 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 2 3/4 512 4800 16-QAM 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 4 1/2 512 6400 16-QAM 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 4 3/4 512 9600 64-QAM 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 6 2/3 512 12800 64-QAM 16MHz 64kHz 15.625 µs 0.25 ms 0.0625 ms 0.3125 ms 3200 Hz 6 3/4 512 14400 =========== ======== ======== ============ ============= =========== ================== ========= ============ =========== =========== =========== .. _physical_rates_ah_step17: .. tab-set:: .. tab-item:: Reference links * Reference links