802.11aj 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 802.11aj?** Physical rates define the data transmission speeds achievable over the wireless channel, determined by modulation, coding, and bandwidth. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What frequency bands does 802.11aj operate in?** 802.11aj primarily operates in the 45 GHz and 60 GHz mmWave bands. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What modulation schemes are used for physical rates in 802.11aj?** 802.11aj uses BPSK, QPSK, 16-QAM, 64-QAM, and 256-QAM modulation schemes. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What coding rates are supported in 802.11aj PHY?** Coding rates include 1/2, 2/3, 3/4, and 5/6 to balance reliability and throughput. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does symbol duration affect physical rates?** Symbol length impacts data throughput; shorter symbols allow higher rates but require better channel conditions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the maximum PHY rate supported by 802.11aj?** The maximum rate depends on modulation and bandwidth but can exceed multiple Gbps under optimal conditions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the number of spatial streams (NSS) affect physical rates?** Increasing NSS multiplies throughput by transmitting parallel data streams via MIMO. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are channel bandwidths wider in 802.11aj compared to previous standards?** Yes, 802.11aj supports channel bandwidths up to 2.16 GHz to enable very high data rates. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11aj support OFDM or SC PHY?** 802.11aj primarily uses OFDM PHY similar to 802.11ad, optimized for mmWave. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How many usable subcarriers are in 802.11aj OFDM?** 52 subcarriers are typically used, matching 802.11ad standards. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are physical rates affected by beamforming in 802.11aj?** Yes, beamforming improves SNR, enabling higher modulation schemes and faster physical rates. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11aj use any new coding techniques?** It builds on LDPC and convolutional coding used in previous standards for error correction. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How is rate adaptation handled in 802.11aj?** Devices dynamically select the best modulation and coding based on channel conditions to optimize rates. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can 802.11aj physical rates be directly compared with 802.11ad?** They are similar but 802.11aj extends to the 45 GHz band with additional features. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What role does symbol length of 3.6 µs play in rates?** The 3.6 µs symbol length balances between multipath resilience and throughput in mmWave environments. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Are there physical rate differences between single-user and multi-user transmissions?** Multi-user MIMO can aggregate rates across users but individual user rates depend on link quality. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does 802.11aj handle rate fallback?** The MAC layer can command rate fallback to lower modulation and coding for reliable links. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What determines the choice of modulation and coding scheme (MCS) in 802.11aj?** Channel conditions, SNR, and interference levels guide the MCS selection to maximize throughput and reliability. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`physical_rates in 802.11ad ` * :ref:`Reference links ` .. _physical_rates_aj_step4: .. tab-set:: .. tab-item:: physical_rates in 802.11aj ============ ======= ====== ============ ============ ============ ================ ========= ============ =========== ========== ============ Modulation BW(GHz) Tsc FSP=BW/Tsc Tdata=1/FSP GI=Tdata/4 Symbol=Tdata+GI 1/Symbol Bits/Symbol Code rate Usable sc Rate ============ ======= ====== ============ ============ ============ ================ ========= ============ =========== ========== ============ π/2-BPSK 4.32 0.568 7605.64 0.131 ns 0.033 ns 0.164 ns 6.10 Gsym 1 1/2 64 770 Mbps π/2-BPSK 4.32 0.568 7605.64 0.131 ns 0.033 ns 0.164 ns 6.10 Gsym 1 13/16 64 2.00 Gbps π/2-QPSK 4.32 0.568 7605.64 0.131 ns 0.033 ns 0.164 ns 6.10 Gsym 2 1/2 64 1.54 Gbps QPSK 4.32 0.568 7605.64 0.131 ns 0.033 ns 0.164 ns 6.10 Gsym 2 13/16 64 3.08 Gbps 16-QAM 4.32 0.568 7605.64 0.131 ns 0.033 ns 0.164 ns 6.10 Gsym 4 3/4 64 6.16 Gbps 16-QAM 4.32 0.568 7605.64 0.131 ns 0.033 ns 0.164 ns 6.10 Gsym 4 13/16 64 9.24 Gbps 64-QAM 4.32 0.568 7605.64 0.131 ns 0.033 ns 0.164 ns 6.10 Gsym 6 13/16 64 13.5 Gbps ============ ======= ====== ============ ============ ============ ================ ========= ============ =========== ========== ============ .. _physical_rates_aj_step17: .. tab-set:: .. tab-item:: Reference links * Reference links