# US 10,312,996 B2 · Systems and methods for using adaptive coding and modulation in a regenerative satellite communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,996 B2 - Document ID: US10312996B2 - Status: Granted - Kind: B2 - Application number: 15/281,737 - Filed: 2016-09-30 - Published: 2018-06-14 - Granted: 2019-06-04 - Earliest claimed: 2016-09-30 - Assignees: Hughes Network Systems, LLC - Applicants: Hughes Network Systems, LLC - Inventors: George Choquette - Web page: https://patentgrep.com/patent/US10312996B2 ## CPC - H04B 7/18513: {Transmission in a satellite or space-based system} - H04B 7/18521: {Systems of inter linked satellites, i.e. inter satellite service (for optical links between satellites H04B10/118)} - H04B 7/18543: {for adaptation of transmission parameters, e.g. power control (for detecting or preventing errors in the information received H04L1/00)} - H04L 1/0003: {by switching between different modulation schemes} - H04L 1/0009: {by adapting the channel coding (H04L1/1812 takes precedence)} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Techniques are described for implementing adaptive coding and modulation (ACM) in regenerative satellite systems to adapt the modulation and/or FEC coding of transmitted waveforms to the conditions of the link. In a first implementation, ACM is implemented on an uplink from a terminal to a regenerative satellite. In this implementation, an uplink modulation and coding combination (ModCod) is estimated by the transmitting terminal based on the quality of signals received from the regenerative satellite on the downlink. In a second implementation, ACM may be implemented on a downlink from a regenerative satellite to a terminal. In this implementation, a transmit terminal may insert a field in a transmitted packet header that indicates a downlink ModCod to be used by the regenerative satellite when transmitting packets to a receiving terminal. The regenerative satellite may reencode and remodulate the packet using the ModCod indicated in the field of the packet header. ## Claims ### Claim 1 A method, comprising: receiving from a first terminal, at a second terminal, at least one of a downlink modulation and coding combination (ModCod) and receive signal metrics; in response to receiving the at least one of a downlink ModCod and receive signal metrics, the second terminal inserting into a header of a packet a field indicating a downlink ModCod to be used by a regenerative satellite when transmitting on a downlink to the first terminal, wherein the packet destination is the first terminal; and after inserting the field indicating the downlink ModCod into the header of the packet, transmitting, on an uplink, the packet from the second terminal to a regenerative satellite. ### Claim 2 (depends on 1) The method of claim 1, wherein the at least one of the downlink ModCod and receive signal metrics is a downlink ModCod. ### Claim 3 (depends on 2) The method of claim 2, further comprising, in response to receiving the downlink ModCod, the second terminal updating a table indicating a downlink ModCod for the first terminal. ### Claim 4 (depends on 2) The method of claim 2, wherein the regenerative satellite is of a satellite-constellation comprising a plurality of regenerative satellites connected using inter-satellite links, and wherein the packet contains a field for routing the packet to one of the plurality of satellites. ### Claim 5 (depends on 2) The method of claim 2, wherein the second terminal comprises at least one of a gateway, a hub, and an earth station. ### Claim 6 (depends on 2) The method of claim 2, wherein the second terminal comprises a very small aperture terminal (VSAT). ### Claim 7 (depends on 2) The method of claim 2, wherein the receive signal metrics comprise a ratio of mean energy per symbol to noise power spectral density (EsN0), the method further comprising the second terminal mapping the EsN0 to the downlink ModCod. ### Claim 8 A method, comprising: receiving a signal at a regenerative satellite; demodulating and decoding the received signal at the regenerative satellite to obtain a packet; reading, from a header of the packet, a field indicating a downlink modulation and coding combination (ModCod) to be used when transmitting on a downlink to a receiving terminal that is a destination of the packet; and modulating and encoding the packet at the regenerative satellite based on the indicated downlink ModCod. ### Claim 9 (depends on 8) The method of claim 8, wherein the signal is received by the regenerative satellite from a second regenerative satellite connected to the regenerative satellite over an inter satellite link. ### Claim 10 (depends on 9) The method of claim 9, wherein the regenerative satellites are in elliptical orbit or in low earth orbit. ### Claim 11 (depends on 8) The method of claim 8, wherein the signal is received by the regenerative satellite on an uplink from a transmitting terminal transmitting to the receiving terminal. ### Claim 12 (depends on 8) The method of claim 8, further comprising: transmitting, on a downlink, the modulated and encoded packet to the receiving terminal. ### Claim 13 (depends on 8) The method of claim 8, further comprising: determining at the regenerative satellite system if a destination downlink of the packet is a downlink of a different satellite. ### Claim 14 A method, comprising: receiving a signal at a regenerative high altitude platform; demodulating and decoding the received signal at the regenerative high altitude platform to obtain a packet; reading, from a header of the packet, a field indicating a downlink modulation and coding combination (ModCod) to be used when transmitting on a downlink to a receiving terminal that is a destination of the packet; modulating and encoding the packet at the regenerative high altitude platform based on the indicated downlink ModCod; and transmitting, on a downlink, the modulated and encoded packet to the receiving terminal. ### Claim 15 (depends on 14) The method of claim 14, wherein the high altitude platform comprises an aircraft. ### Claim 16 (depends on 14) The method of claim 14, wherein the high altitude platform comprises a balloon. ### Claim 17 A regenerative satellite system, comprising: a regenerative satellite, the regenerative satellite comprising: a receiver configured to receive a signal; circuitry for demodulating and decoding the received signal to obtain a packet; circuitry for reading, from a header of the packet, a field indicating a downlink modulation and coding combination (ModCod) to be used when transmitting on a downlink to a receiving terminal that is a destination of the packet; and circuitry for modulating and encoding the packet at the regenerative satellite based on the indicated downlink ModCod. ### Claim 18 (depends on 17) The regenerative satellite system of claim 17, further comprising a second regenerative satellite connected to the regenerative satellite over an inter satellite link. ### Claim 19 (depends on 18) The regenerative satellite system of claim 18, wherein the regenerative satellites are in elliptical orbit or in low earth orbit. ### Claim 20 (depends on 18) The regenerative satellite system of claim 18, further comprising: circuitry for determining if a destination downlink of the packet is a downlink of a different satellite. ### Claim 21 (depends on 17) The regenerative satellite system of claim 17, wherein the signal is received by the regenerative satellite on an uplink from a transmitting terminal transmitting to the receiving terminal. ### Claim 22 (depends on 17) The regenerative satellite system of claim 17, wherein the signal is received by the regenerative satellite from a second regenerative satellite connected to the regenerative satellite over an inter satellite link.