# US 12,120,025 B2 · Physical layer preamble design > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,025 B2 - Document ID: US12120025B2 - Status: Granted - Kind: B2 - Application number: 17/323,563 - Filed: 2021-05-18 - Published: 2021-11-25 - Granted: 2024-10-15 - Earliest claimed: 2020-05-19 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Jialing Li Chen; Sameer Vermani; Bin Tian - Web page: https://patentgrep.com/patent/US12120025B2 ## CPC - H04L 27/2603: {Signal structure ensuring backward compatibility with legacy system} - H04L 45/74: Address processing for routing - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract This disclosure provides methods, devices and systems for generating packet preambles. Some implementations more specifically relate to preamble designs that support gains in data throughput achievable in accordance with the IEEE 802.11 be amendment, and future generations, of the IEEE 802.11 standard. Among other examples, the preamble designs of the present implementations may allow for more reliable packet detection, more accurate channel estimation, and more robust decoding of signal field (SIG) symbols. Additionally, or alternatively, the preamble designs of the present disclosure may be implemented with different lengths, modulation schemes, or transmit power compared to preamble designs that conform to existing versions of the IEEE 802.11 standard. ## Claims ### Claim 1 A method for wireless communication by a wireless communication device comprising: receiving a packet including a physical layer preamble that includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repeat of L-SIG (RL-SIG) that immediately follows L-SIG, and a universal signal field (U-SIG) that immediately follows RL-SIG and includes information for interpreting one or more subsequent fields of the packet, L-SIG including a length field having a value (L_LEN) that satisfies L_LEN mod 3 equals zero; detecting a plurality of modulation schemes applied to U-SIG, wherein a first symbol of U-SIG is modulated according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes and a second symbol of U-SIG is modulated according to a quadrature BPSK (QBPSK) modulation scheme of the plurality of modulation schemes; and determining the second symbol of U-SIG is a repetition of the first symbol of U-SIG based on the first symbol being modulated according to the BPSK modulation scheme and the second symbol being modulated according to the QBPSK modulation scheme. ### Claim 2 (depends on 1) The method of claim 1, further comprising: determining that U-SIG further includes at least a third symbol and a fourth symbol based on determining that the second symbol of U-SIG is modulated according to the QBPSK modulation scheme, the first symbol of U-SIG carrying first coded bits that are the same as second coded bits carried by the second symbol of U-SIG, and the third symbol of U-SIG carrying third coded bits that are the same as fourth coded bits carried by the fourth symbol of U-SIG. ### Claim 3 (depends on 2) The method of claim 2, wherein each of the first and second symbols is transmitted on a plurality of subcarriers, the first coded bits of the first symbol being modulated on the plurality of subcarriers in a different order than the second symbol. ### Claim 4 (depends on 2) The method of claim 2, wherein each of the third and fourth symbols is transmitted on a plurality of subcarriers, the second coded bits of the third symbol being modulated on the plurality of subcarriers in a different order than the fourth symbol. ### Claim 5 (depends on 1) The method of claim 1, further comprising: determining a timing of a non-legacy short training field (STF) of the physical layer preamble in relation to U-SIG based on the second symbol being the repetition of the first symbol; and initiating automatic gain control (AGC) based on the timing of the non-legacy STF. ### Claim 6 (depends on 5) The method of claim 5, wherein the packet includes one or more padding symbols between U-SIG and the non-legacy STF. ### Claim 7 (depends on 1) The method of claim 1, further comprising: determining that the packet conforms with a non-legacy extended range (ER) packet format based on a value of a version identifier subfield of U-SIG and the second symbol of U-SIG being modulated according to the QBPSK modulation scheme. ### Claim 8 (depends on 7) The method of claim 7, wherein the physical layer preamble further includes a non-legacy signal field following U-SIG, the non-legacy signal field including a single user field and one or more bits of overflow from U-SIG. ### Claim 9 (depends on 7) The method of claim 7, wherein U-SIG includes a user field carrying user-specific information for a single user, the physical layer preamble further including a non-legacy STF following U-SIG. ### Claim 10 A wireless communication device comprising: one or more processors; one or more memories coupled with the one or more processors; and one or more processor-readable instructions store in the one or more memories and executable by the one or more processors to cause the wireless communication device to: receive a packet including a physical layer preamble that includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repeat of L-SIG (RL-SIG) that immediately follows L-SIG, and a universal signal field (U-SIG) that immediately follows RL-SIG and includes information for interpreting one or more subsequent fields of the packet, L-SIG including a length field having a value (L_LEN) that satisfies L_LEN mod 3 equals zero; detect a plurality of modulation schemes applied to U-SIG, wherein a first symbol of U-SIG is modulated according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes and a second symbol of U-SIG is modulated according to a quadrature BPSK (QBPSK) modulation scheme of the plurality of modulation schemes; and determine the second symbol of U-SIG is a repetition of the first symbol of U-SIG based on the first symbol being modulated according to the BPSK modulation scheme and the second symbol being modulated according to the QBPSK modulation scheme. ### Claim 11 (depends on 10) The wireless communication device of claim 10, wherein execution of the processor-readable instructions is further configured to: determine that U-SIG further includes at least a third symbol and a fourth symbol based on determining that the second symbol of U-SIG is modulated according to the QBPSK modulation scheme, wherein the first symbol of U-SIG carries first coded bits that are the as second coded bits carried by the second symbol of U-SIG, and the third symbol of U-SIG carrying third coded bits that are the same as fourth coded bits carried by the fourth symbol of U-SIG. ### Claim 12 (depends on 11) The wireless communication device of claim 11, wherein the first coded bits of the first symbol are modulated on a plurality of subcarriers in a different order than the second symbol, and wherein the second coded bits of the third symbol are modulated on the plurality of subcarriers in a different order than the fourth symbol. ### Claim 13 (depends on 10) The wireless communication device of claim 10, wherein execution of the processor-readable instructions is further configured to: determine a timing of a non-legacy short training field (STF) of the physical layer preamble in relation to U-SIG based on the second symbol being the repetition of the first symbol; and initiate automatic gain control (AGC) based on the timing of the non-legacy STF. ### Claim 14 (depends on 13) The wireless communication device of claim 13, wherein the packet includes one or more padding symbols between U-SIG and the non-legacy STF. ### Claim 15 A method for wireless communication by a wireless communication device comprising: generating a packet including a physical layer preamble that includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repeat of L-SIG (RL-SIG) that immediately follows L-SIG, and a universal signal field (U-SIG) that immediately follows RL-SIG and includes information for interpreting one or more subsequent fields of the packet, L-SIG including a length field having a value (L_LEN) that satisfies L_LEN mod 3 equals zero; selecting a plurality of modulation schemes to apply to U-SIG to indicate a presence of a repetition of one or more symbols of U-SIG; modulating a first symbol of the one or more symbols of U-SIG according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes; modulating a second symbol of U-SIG according to a quadrature BPSK (QBPSK) modulation scheme of the plurality of modulation schemes based at least in part on the second symbol being a repetition of the first symbol; and transmitting the packet over a wireless channel. ### Claim 16 (depends on 15) The method of claim 15, wherein U-SIG further includes at least a third symbol of the one or more symbols and a fourth symbol, the first symbol of U-SIG carrying first coded bits that are the same as second coded bits carried by the second symbol of U-SIG, and the third symbol of U-SIG carrying third coded bits that are the same as fourth coded bits carried by the fourth symbol of U-SIG. ### Claim 17 (depends on 16) The method of claim 16, wherein the first coded bits of the first symbol are modulated on a plurality of subcarriers in a different order than the second symbol. ### Claim 18 (depends on 16) The method of claim 16, wherein the second coded bits of the third symbol are modulated on a plurality of subcarriers in a different order than the fourth symbol. ### Claim 19 (depends on 16) The method of claim 16, wherein the packet includes one or more padding symbols between U-SIG and a non-legacy short training field (STF) of the physical layer preamble. ### Claim 20 (depends on 16) The method of claim 16, wherein the packet conforms with a non-legacy extended range (ER) packet format having a bandwidth equal to 20 megahertz. ### Claim 21 (depends on 20) The method of claim 20, wherein the physical layer preamble further includes a non-legacy signal field following U-SIG, the non-legacy signal field including a single user field and one or more bits of overflow from U-SIG. ### Claim 22 (depends on 20) The method of claim 20, wherein U-SIG includes a user field carrying user-specific information for a single user, the physical layer preamble further including a non-legacy STF following U-SIG. ### Claim 23 A wireless communication device comprising: one or more processors; one or more memories coupled with the one or more processors; and one or more processor-readable instructions store in the one or more memories and executable by the one or more processors to cause the wireless communication device to: generate a packet including a physical layer preamble that includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repeat of L-SIG (RL-SIG) that immediately follows L-SIG, and a universal signal field (U-SIG) that immediately follows RL-SIG and includes information for interpreting one or more subsequent fields of the packet, L-SIG including a length field having a value (L_LEN) that satisfies L_LEN mod 3 equals zero; select a plurality of modulation schemes to apply to U-SIG to indicate a presence of a repetition of one or more symbols of U-SIG; modulate a first symbol of the one or more symbols of U-SIG according to a binary phase shift keying (BPSK) modulation scheme of the plurality of modulation schemes; modulate a second symbol of U-SIG according to a quadrature BPSK (QBPSK) modulation scheme of the plurality of modulation schemes based at least in part on the second symbol being a repetition of the first symbol; and transmit the packet over a wireless channel. ### Claim 24 (depends on 23) The wireless communication device of claim 23, wherein U-SIG further includes at least a third symbol of the one or more symbols and a fourth symbol, the first symbol of U-SIG carrying first coded bits that are the same as second coded bits carried by the second symbol of U-SIG, and the third symbol of U-SIG carrying third coded bits that are the same as fourth coded bits carried by the fourth symbol of U-SIG. ### Claim 25 (depends on 24) The wireless communication device of claim 24, wherein the first coded bits of the first symbol are modulated on a plurality of subcarriers in a different order than the second symbol, wherein the second coded bits of the third symbol are modulated on the plurality of subcarriers in a different order than the fourth symbol. ### Claim 26 (depends on 23) The wireless communication device of claim 23, wherein the packet conforms with a non-legacy extended range (ER) packet format having a bandwidth equal to 20 megahertz. ### Claim 27 (depends on 26) The wireless communication device of claim 26, wherein the physical layer preamble further includes a non-legacy signal field following U-SIG, the non-legacy signal field including a single user field and one or more bits of overflow from U-SIG. ### Claim 28 (depends on 26) The wireless communication device of claim 26, wherein U-SIG includes a user field carrying user-specific information for a single user, the physical layer preamble further includes a non-legacy STF following U-SIG.