# US 10,374,667 B2 · Pilot scheme for a MIMO communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,667 B2 - Document ID: US10374667B2 - Status: Granted - Kind: B2 - Application number: 14/496,001 - Filed: 2014-09-25 - Published: 2015-02-19 - Granted: 2019-08-06 - Earliest claimed: 2005-09-30 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Jianglei Ma; Ming Jia; Hua Xu; Wen Tong; Peiying Zhu; Moussa Abdi - Web page: https://patentgrep.com/patent/US10374667B2 ## CPC - H04B 7/0452: Multi-user MIMO systems - H04B 7/0413: MIMO systems - H04J 13/18: Allocation of orthogonal codes - H04L 5/001: {the frequencies being arranged in component carriers} - H04L 5/0026: {Division using four or more dimensions, e.g. beam steering or quasi-co-location [QCL]} - 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 27/2613: {Structure of the reference signals} - H04W 72/04: Wireless resource allocation - H04W 72/044: based on the type of the allocated resource - H04W 88/08: Access point devices - H04J 2013/165: {Joint allocation of code together with frequency or time} - H04L 1/0625: {Transmitter arrangements} - H04L 5/0032: {Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation} - H04L 25/0226: {sounding signals per se} - H04L 25/0228: {with direct estimation from sounding signals} - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols. ## Claims ### Claim 1 A method of transmitting sounding pilot information, the method comprising: a mobile terminal performing, generating sounding pilot information based on an orthogonal code assignment; mapping the sounding pilot information onto an allocation of a plurality of subcarriers, wherein the allocation of the plurality of subcarriers is every second subcarrier of one or more blocks of subcarriers of a plurality of blocks of subcarriers on at least one symbol in a transmission time interval (TTI), wherein the allocation corresponds to half of the plurality of subcarriers of the one or more blocks of subcarriers on each symbol of the at least one symbol, wherein the TTI comprises a plurality of symbols, and wherein each block of the one or more blocks of subcarriers comprises two or more contiguous subcarriers; and transmitting the sounding pilot information on the at least one symbol of the plurality of symbols in the TTI. ### Claim 2 (depends on 1) The method of claim 1, further comprising: mapping the sounding pilot information for the mobile terminal onto the last symbol of the TTI. ### Claim 3 (depends on 1) The method of claim 1, further comprising: mapping the sounding pilot information for the mobile terminal onto the allocation of the plurality of subcarriers on the at least one symbol, wherein the sounding pilot information for the mobile terminal and sounding pilot information for one or more other mobile terminals are mapped to different subcarriers. ### Claim 4 (depends on 1) The method of claim 1, wherein the sounding pilot information for the mobile terminal and sounding pilot information for at least one other mobile terminal are generated with different orthogonal codes. ### Claim 5 (depends on 4) The method of claim 4, wherein the sounding pilot information for the mobile terminal and sounding pilot information for one or more other mobile terminals are mapped to common subcarriers. ### Claim 6 (depends on 1) The method of claim 1, wherein said generating sounding pilot information comprises: generating first sounding pilot information for a first antenna of the mobile terminal; and generating second sounding pilot information for a second antenna of the mobile terminal; wherein the method further comprises: mapping the first sounding pilot information for the first antenna of the mobile terminal onto the allocation of the plurality of subcarriers on the at least one symbol; and mapping the second sounding pilot information for the second antenna of the mobile terminal onto an allocation of the plurality of subcarriers; wherein the first sounding pilot information and the second sounding pilot information are mapped to different subcarriers. ### Claim 7 (depends on 1) The method of claim 1, wherein said generating sounding pilot information comprises: generating first sounding pilot information for a first antenna of the mobile terminal; and generating second sounding pilot information for a second antenna of the mobile terminal; wherein the first sounding pilot information and the second sounding pilot information are generated with different orthogonal codes. ### Claim 8 (depends on 7) The method of claim 7, further comprising: mapping the first sounding pilot information for the first antenna of the mobile terminal onto the allocation of the plurality of subcarriers on the at least one symbol; and mapping the second sounding pilot information for the second antenna of the mobile terminal onto an allocation of the plurality of subcarriers on the at least one symbol; wherein the first sounding pilot information and the second sounding pilot information are mapped to common subcarriers. ### Claim 9 A mobile terminal, comprising: sounding pilot generation circuitry configured to generate sounding pilot information based on an orthogonal code assignment; subcarrier mapping circuitry configured to map the sounding pilot information onto an allocation of a plurality of subcarriers, wherein the allocation of the plurality of subcarriers is every second subcarrier of one or more blocks of subcarriers of a plurality of blocks of subcarriers on at least one symbol in a transmission time interval (TTI), wherein the allocation corresponds to half of the plurality of subcarriers of the one or more blocks of subcarriers on a symbol, wherein the TTI comprises a plurality of symbols, and wherein each block of the one or more blocks of subcarriers comprises two or more contiguous subcarriers; and transmitter circuitry configured to transmit the sounding pilot information on the at least one symbol of the plurality of symbols in the TTI. ### Claim 10 (depends on 9) The mobile terminal of claim 9, wherein the subcarrier mapping circuitry is further configured to: map sounding pilot information for mobile terminal onto the last symbol of the TTI. ### Claim 11 (depends on 9) The mobile terminal of claim 9, wherein the sounding pilot information for the mobile terminal and sounding pilot information for one or more other mobile terminals are mapped to different subcarriers. ### Claim 12 (depends on 9) The mobile terminal of claim 9, wherein the sounding pilot information for the mobile terminal and sounding pilot information for at least one other mobile terminal are generated with different orthogonal codes. ### Claim 13 (depends on 12) The mobile terminal of claim 12, wherein the sounding pilot information for the mobile terminal and sounding pilot information for one or more other mobile terminals are mapped to common subcarriers. ### Claim 14 (depends on 9) The mobile terminal of claim 9, wherein to generate sounding pilot information, the sounding pilot generation circuitry is further configured to: generate first sounding pilot information for a first antenna of the mobile terminal; and generate second sounding pilot information for a second antenna of the mobile terminal; and wherein the subcarrier mapping circuitry is further configured to: map the first sounding pilot information for the first antenna of the mobile terminal onto the allocation of the plurality of subcarriers on the at least one symbol; and map the second sounding pilot information for the second antenna of the mobile terminal onto an allocation of the plurality of subcarriers; wherein the first sounding pilot information and the second sounding pilot information are mapped to different subcarriers. ### Claim 15 (depends on 9) The mobile terminal of claim 9, wherein to generate sounding pilot information, the sounding pilot generation circuitry is further configured to: generate first sounding pilot information for a first antenna of the mobile terminal; and generate second sounding pilot information for a second antenna of the mobile terminal; wherein the first sounding pilot information and the second sounding pilot information are generated with different orthogonal codes. ### Claim 16 (depends on 15) The mobile terminal of claim 15, wherein the subcarrier mapping circuitry is further configured to: map the first sounding pilot information for the first antenna of the mobile terminal onto the allocation of the plurality of subcarriers on the at least one symbol; and map the second sounding pilot information for the second antenna of the mobile terminal onto an allocation of the plurality of subcarriers on the at least one symbol; wherein the first sounding pilot information and the second sounding pilot information are mapped to common subcarriers. ### Claim 17 A method for transmitting sounding pilot information, the method comprising: a base station performing, transmitting, to a mobile terminal, an orthogonal code assignment; an allocation of a plurality of subcarriers, wherein the allocation of the plurality of subcarriers is every second subcarrier of one or more blocks of subcarriers of a plurality of blocks of subcarriers on at least one symbol in a transmission time interval (TTI), wherein the allocation corresponds to half of the plurality of subcarriers of the one or more blocks of subcarriers on a symbol, wherein the TTI comprises a plurality of symbols, and wherein each block of the one or more blocks of subcarriers comprises two or more contiguous subcarriers; and receiving, from a mobile station, sounding pilot information on the at least one symbol of the plurality of symbols in the TTI, wherein the sounding pilot information is generated based on the orthogonal code assignment, and wherein the sounding pilot information is mapped onto the allocation of the plurality of subcarriers on the at least one symbol based on the allocation. ### Claim 18 (depends on 17) The method of claim 17, wherein the sounding pilot information is mapped onto the allocation of the plurality of subcarriers on the at least one symbol based on the allocation, wherein the sounding pilot information for the mobile terminal and sounding pilot information for one or more other mobile terminals are mapped to different subcarriers. ### Claim 19 (depends on 17) The method of claim 17, wherein the sounding pilot information is generated based on the allocation, wherein the sounding pilot information for the mobile terminal and sounding pilot information for at least one other mobile terminal are generated with different orthogonal codes and mapped onto the allocation of the plurality of on the at least one symbol based on the allocation, and wherein the sounding pilot information for the mobile terminal and sounding pilot information for one or more other mobile terminals are mapped to common subcarriers. ### Claim 20 (depends on 17) The method of claim 17, wherein the sounding pilot information comprises: a first sounding pilot information for a first antenna of the mobile terminal generated based on the allocation, wherein the first sounding pilot information for the first antenna of the mobile terminal is mapped onto the allocation of the plurality of subcarriers on the at least one symbol; a second sounding pilot information for a second antenna of the mobile terminal generated based on the allocation, wherein the second sounding pilot information for the second antenna of the mobile terminal is mapped onto an allocation of the plurality of subcarriers on the at least one symbol; wherein the first sounding pilot information and the second sounding pilot information are generated with different orthogonal codes; and wherein the first sounding pilot information and the second sounding pilot information are mapped to common subcarriers.