Physical Layer Implementation Analysis of IEEE 802.11be Preamble Puncturing in SU Transmission

Due to incumbent technologies in the 6 GHz band, including dynamic frequency selection (DFS) activities such as radar and military communications, as well as interference from other neighboring Wi-Fi networks in dense and highly competitive environments, contiguous wide channel bandwidths like 80, 160, 240, and 320 MHz may not always be available for wireless local area network (WLAN) deployment. To address these challenges, preamble puncturing has been adopted as a mandatory feature in IEEE 802.11be (Wi-Fi 7). This technique allows nonprimary 20 MHz channels to be excluded in transmission bandwidths of 80 MHz or greater. While the implementation of preamble puncturing has been demonstrated in multiple-users (MU) scenarios with orthogonal frequency division multiple access (OFDMA) in IEEE 802.11ax (Wi-Fi 6) downlink transmissions, its feasibility, especially for single-user (SU) transmission at the physical (PHY) layer, including resource units (RUs) aggregation in IEEE 802.11be, remains under investigation, with ongoing research efforts. This paper explores preamble puncturing in SU transmissions, tracing its evolution from IEEE 802.11ax to its anticipated implementation in IEEE 802.11be. Our study including simulations results reveal that preamble puncturing with PHY Option 3 offers significant benefits, including reduced hardware complexity and lower transmission airtime. This approach involves aggregating non-contiguous available RUs with a post-channel encoding parser. It is well-aligned with both current and future IEEE 802.11 PHY processing standards, including joint low-density parity check (LDPC) encoding. For RUs affected by DFS or other transmissions, signal power must be reduced to remain below the clear channel assessment (CCA) threshold. Our findings indicate that incorporating contaminated RUs with negligible signal power into the aggregation results in minimal signal-to-noise ratio (SNR) wastage across most puncturing options outlined in the IEEE 802.11 specification.