# US 8,542,771 B2 · Methods and systems for orthogonal frequency division multiplexing (OFDM) multiple zone partitioning > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,771 B2 - Document ID: US8542771B2 - Status: Granted - Kind: B2 - Application number: 13/292,643 - Filed: 2011-11-09 - Published: 2012-03-01 - Granted: 2013-09-24 - Earliest claimed: 2005-08-23 - Assignees: Apple Inc. - Applicants: Jianglei Ma; Ming Jia; Wen Tong; Peiying Zhu; Hang Zhang; Mo-Han Fong - Inventors: Jianglei Ma; Ming Jia; Wen Tong; Peiying Zhu; Hang Zhang; Mo-Han Fong - Web page: https://patentgrep.com/patent/US8542771B2 ## CPC - H04L 27/2602: {Signal structure} - H04B 7/06: at the transmitting station - H04B 7/08: at the receiving station - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 5/0023: {Time-frequency-space} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04L 25/02: Details {; arrangements for supplying electrical power along data transmission lines (systems for transmitting signals via power distribution lines H04B3/54)} - H04L 25/0226: {sounding signals per se} - H04L 25/0232: {by interpolation between sounding signals} - H04L 27/2647: {Arrangements specific to the receiver only (equalisation H04L27/01)} - H04W 52/325: {Power control of control or pilot channels} - H04L 1/0003: {by switching between different modulation schemes} - H04L 1/0009: {by adapting the channel coding (H04L1/1812 takes precedence)} - H04L 1/0618: {Space-time coding} - H04L 27/26134: {Pilot insertion in the transmitter chain, e.g. pilot overlapping with data, insertion in time or frequency domain} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Aspects of the invention include methods and devices for inserting data and pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames having a time domain and a frequency domain. A method involves inserting in at least one zone of a first type a two dimensional array of data and pilot symbols in time and frequency and inserting in at least one zone of a second type a two dimensional array of data and pilot symbols in time and frequency. In some implementations the zone of the first type comprises common pilot symbols that can be detected by all receivers receiving the OFDM frame. In some implementations the zone of the second type comprises dedicated pilot symbols that are only detectable by a receiver that is aware of pre-processing used to encode the dedicated pilot symbols. ## Claims ### Claim 1 A method for inserting data and pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) symbols for transmission on at least one transmitting antenna, each OFDM symbol comprising a plurality of sub-carriers, a number of successive OFDM symbols being grouped into each of a plurality of transmission time intervals, the method comprising: grouping the transmission time intervals into successive blocks, each block comprising an even number of transmission time intervals; and inserting data and pilot symbols in a pre-defined time-frequency pattern in each block. ### Claim 2 (depends on 1) The method of claim 1, wherein the pilot symbols are inserted in a plurality of regularly spaced OFDM symbols in each block. ### Claim 3 (depends on 1) The method of claim 1, wherein the pilot symbols are inserted in a plurality of regularly spaced subcarriers in each block. ### Claim 4 (depends on 1) The method of claim 1, wherein the pilot symbols are inserted in a regular diagonal lattice in each block. ### Claim 5 (depends on 1) The method of claim 1, wherein the pilot symbols are inserted in a diamond shaped lattice in each block. ### Claim 6 (depends on 1) The method of claim 1, wherein the pilot symbols comprise common pilot symbols for use by a plurality of receivers and dedicated pilot symbols, each dedicated pilot symbol being dedicated to a respective receiver. ### Claim 7 (depends on 1) The method of claim 1, wherein at least one block uses a first multiple input multiple output (MIMO) format and at least one other block uses at least one other MIMO format. ### Claim 8 (depends on 1) The method of claim 1, comprising: inserting the data and pilot symbols in a first pre-defined time-frequency pattern in each block for transmission by a first antenna; and inserting the data and pilot symbols in a second pre-defined time-frequency pattern in each block for transmission by a second antenna; the first time-frequency pattern having nulls corresponding to locations of pilot symbols in the second time-frequency pattern; and the second time-frequency pattern having nulls corresponding to locations of pilot symbols in the first time-frequency pattern. ### Claim 9 (depends on 1) The method of claim 1, wherein each block consists of 12 sub-carriers over an even number of transmission time intervals. ### Claim 10 (depends on 1) The method of claim 1, wherein each transmission time interval consists of an odd number of successive OFDM symbols. ### Claim 11 (depends on 6) The method of claim 6, wherein: the common pilot symbols are inserted in a first regular diagonal lattice in each block; and the dedicated pilot symbols are inserted in a second regular diagonal lattice in each block, the second regular diagonal lattice being offset from the first regular diagonal lattice. ### Claim 12 (depends on 7) The method of claim 7, wherein the MIMO formats are selected from a group consisting of open loop OFDM MIMO, OFDM beam forming, Bell Laboratories Layered Space-Time (BLAST), spatial multiplexing, and space-time transmit diversity. ### Claim 13 An Orthogonal Frequency Division Multiplexing (OFDM) transmitter, comprising: coding logic operable to insert data and pilot symbols into OFDM symbols, each OFDM symbol comprising a plurality of sub-carriers, a number of successive OFDM symbols being grouped into each of a plurality of transmission time intervals, the transmission time intervals being grouped into successive blocks, each block comprising an even number of transmission time intervals, and data and pilot symbols being inserted in a pre-defined time-frequency pattern in each block; and at least one antenna for transmission of the OFDM symbols. ### Claim 14 (depends on 13) The OFDM transmitter of claim 13, wherein the pilot symbols are inserted in a plurality of regularly spaced OFDM symbols in each block. ### Claim 15 (depends on 13) The OFDM transmitter of claim 13, wherein the pilot symbols are inserted in a plurality of regularly spaced subcarriers in each block. ### Claim 16 (depends on 13) The OFDM transmitter of claim 13, wherein the pilot symbols are inserted in a regular diagonal lattice in each block. ### Claim 17 (depends on 13) The OFDM transmitter of claim 13, wherein the pilot symbols are inserted in a diamond shaped lattice in each block. ### Claim 18 (depends on 13) The OFDM transmitter of claim 13, wherein the pilot symbols comprise common pilot symbols for use by a plurality of receivers and dedicated pilot symbols, each dedicated pilot symbol being dedicated to a respective receiver. ### Claim 19 (depends on 13) The OFDM transmitter of claim 13, wherein at least one block uses a first multiple input multiple output (MIMO) format and at least one other block uses at least one other MIMO format. ### Claim 20 (depends on 13) The OFDM transmitter of claim 13, wherein: the at least one antenna comprises at least first and second antennas; and the coding logic is operable to: insert the data and pilot symbols in a first pre-defined time-frequency pattern in each block for transmission by the first antenna; and insert the data and pilot symbols in a second pre-defined time-frequency pattern in each block for transmission by the second antenna; the first time-frequency pattern having nulls corresponding to locations of pilot symbols in the second time-frequency pattern; and the second time-frequency pattern having nulls corresponding to locations of pilot symbols in the first time-frequency pattern. ### Claim 21 (depends on 13) The OFDM transmitter of claim 13, wherein each block consists of 12 sub-carriers over an even number of transmission time intervals. ### Claim 22 (depends on 13) The OFDM transmitter of claim 13, wherein each transmission time interval consists of an odd number of successive OFDM symbols. ### Claim 23 (depends on 18) The OFDM transmitter of claim 18, wherein: the common pilot symbols are inserted in a first regular diagonal lattice in each block; and the dedicated pilot symbols are inserted in a second regular diagonal lattice in each block, the second regular diagonal lattice being offset from the first regular diagonal lattice. ### Claim 24 (depends on 19) The OFDM transmitter of claim 19, wherein the MIMO formats are selected from a group consisting of open loop OFDM MIMO, OFDM beam forming, Bell Laboratories Layered Space-Time (BLAST), spatial multiplexing, and space-time transmit diversity.