# US 2019/0245604 A1 · Systems and Methods for Random Access Communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0245604 A1 - Document ID: US20190245604A1 - Status: Published application - Kind: A1 - Application number: 16/258,448 - Filed: 2019-01-25 - Published: 2019-08-08 - Earliest claimed: 2018-01-26 - Assignees: California Institute of Technology - Applicants: California Institute of Technology - Inventors: Michelle Effros; Victoria Kostina; Recep C. Yavas - Web page: https://patentgrep.com/patent/US20190245604A1 ## CPC - H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection} - H03M 13/3761: {using code combining, i.e. using combining of codeword portions which may have been transmitted separately, e.g. Digital Fountain codes, Raptor codes or Luby Transform [LT] codes} - H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection} - H04L 1/0041: {Arrangements at the transmitter end} - H04L 1/0045: {Arrangements at the receiver end} - H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)} - H04L 5/1446: {of transmission speed} - H04L 27/26: Systems using multi-frequency codes (H04L27/32 takes precedence) - H04L 2001/0093: {Point-to-multipoint} - H04B: TRANSMISSION - H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Systems and methods for random access communication in accordance with various embodiments of the invention are described in which receivers can handle uncoordinated transmissions of a large and unknown number of transmitters. Communication systems in accordance with many embodiments of the invention include a plurality of transmitters that encode message data as symbols using a rateless code. During transmission, the transmitters receive feedback messages at a predetermined set of potential decoding times until an end of epoch message is received. A receiver transmits at least one start of epoch message and, at each of a predetermined set of decoding times, determines whether a decoding rule is satisfied. When the decoding rule is satisfied, the receiver can decode at least one message from observed symbols based upon the rateless code. The receiver can end the transmission epoch by transmitting an end of epoch message. ## Claims ### Claim 1 A communication system, comprising: a plurality of transmitters that each comprise an encoder, wherein the encoder of a given transmitter is configured to: receive a start of epoch message; select a codebook: encode message data as symbols using a rateless code determined using the selected codebook; and receive feedback messages at a predetermined set of potential decoding times; wherein the transmitter is configured to transmit symbols until a received feedback message is an end of epoch message; and a receiver comprising a decoder, where the decoder is configured to: select at least one codebook; cause a broadcast transmitter to transmit at least one start of epoch message; receive observed symbols; at each of a predetermined set of decode times, determine whether a decoding rule is satisfied; and when the decoding rule is satisfied: decode at least one message based upon the received observed symbols based upon the rateless code and the selected at least one codebook; and cause the broadcast transmitter to transmit an end of epoch message. ### Claim 2 (depends on 1) The communication system of claim 1, wherein the determination of whether a decoding rule is satisfied is based upon the received observed symbols. ### Claim 3 (depends on 1) The communication system of claim 1, wherein the transmitter is configured to select a codebook based upon the start of epoch message. ### Claim 4 (depends on 1) The communication system of claim 1, wherein the broadcast transmitter transmits the at least one start of epoch message based upon the selected at least one codebook. ### Claim 5 (depends on 1) The communication system of claim 1, wherein the broadcast transmitter is further configured to transmit at least one additional message based upon the selected at least one codebook. ### Claim 6 (depends on 1) The communication system of claim 1, wherein multiple transmitters in the plurality of transmitters are configured to select the same codebook to use in the encoding of message data as symbols using a rateless code. ### Claim 7 (depends on 1) The communication system of claim 1, wherein at least two of the plurality of transmitters are configured to select different codebooks to use in the encoding of message data as symbols using a rateless code. ### Claim 8 (depends on 7) The communication system of claim 7, wherein the receiver applies decoding rules at separate predetermined times with respect to each of the different codebooks. ### Claim 9 (depends on 1) The communication system of claim 1, wherein the broadcast transmitter sends a negative acknowledgement feedback message when the decoding rule is not satisfied at a predetermined decode time. ### Claim 10 (depends on 1) The communication system of claim 1, wherein the encoder is configured to continue to encode message data as symbols using a rateless code determined using the selected codebook in response to receipt of a negative acknowledgement feedback message. ### Claim 11 A transmitter system, comprising: a receiver configured to receive a start of epoch message; an encoder configured to: select a codebook; encode message data as symbols using a rateless code determined using the selected codebook; and a modulator configured to transmit symbols encoded by the encoder; wherein the receiver is further configured to receive an end of epoch message at one of a predetermined set of times; and wherein the modulator is configured to transmit symbols encoded by the encoder until an end of epoch message is received by the receiver. ### Claim 12 (depends on 11) The transmitter system of claim 11, wherein the transmitter is configured to select a codebook based upon the start of epoch message. ### Claim 13 (depends on 11) The transmitter system of claim 11, wherein the encoder is configured to continue to encode message data as symbols using a rateless code determined using the selected codebook in response to receipt of a negative acknowledgement feedback message. ### Claim 14 A receiver system, comprising: a decoder configured to select at least one codebook; a transmitter configured to transmit at least one start of epoch message; a receiver configured to receive observed symbols; wherein the decoder is further configured to: determine whether a decoding rule is satisfied at each of a predetermined set of decode times; and when the decoding rule is satisfied: decode at least one message based upon the received observed symbols based upon a rateless code determined using the selected at least one codebook; and cause the transmitter to transmit an end of epoch message. ### Claim 15 (depends on 1) The receiver system of claim 1, wherein the determination of whether a decoding rule is satisfied is based upon the received observed symbols. ### Claim 16 (depends on 14) The receiver system of claim 14, wherein the transmitter transmits the at least one start of epoch message based upon the selected at least one codebook. ### Claim 17 (depends on 14) The receiver system of claim 14, wherein the transmitter is further configured to transmit at least one additional message based upon the selected at least one codebook. ### Claim 18 (depends on 14) The receiver system of claim 14, wherein the decoder is configured to select a single codebook and determines whether the decoding rule is satisfied assuming that all transmitters are using the single codebook. ### Claim 19 (depends on 14) The receiver system of claim 14, wherein the decoder is configured to select a plurality of different codebooks and and applies decoding rules at separate predetermined times with respect to each of the different codebooks. ### Claim 20 (depends on 14) The receiver system of claim 14, wherein the broadcast transmitter sends a negative acknowledgement feedback message when the decoding rule is not satisfied at a predetermined decode time.