# US 2018/0323929 A1 · Method and apparatus for interference demodulation reference signal detection with serving signal cancellation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0323929 A1 - Document ID: US20180323929A1 - Status: Published application - Kind: A1 - Application number: 16/030,779 - Filed: 2018-07-09 - Published: 2018-11-08 - Earliest claimed: 2017-01-19 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Yoo Jin Choi; Dongwoon Bai; Jungwon Lee; Sungyoon Cho; Heunchul Lee; Sungsoo Kim - Web page: https://patentgrep.com/patent/US20180323929A1 ## CPC - H04W 72/563: of the wireless resources - H04J 11/004: {using regenerative subtractive interference cancellation} - H04J 11/0046: {using joint detection algorithms} - H04L 27/2691: {involving interference determination or cancellation} - H04L 5/0023: {Time-frequency-space} - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - 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) ## Abstract A system and method for characterizing an interference demodulation reference signal (DMRS) in a piece of user equipment (UE), e.g., a mobile device. The UE determines whether the serving signal is transmitted in a DMRS-based transmission mode; if it is, the UE cancels the serving DMRS from the received signal; otherwise the UE cancels the serving data signal from the received signal. The remaining signal is then analyzed for the amount of power it has in each of four interference DMRS candidates, and hypothesis testing is performed to determine whether interference DMRS is present in the signal, and, if so, to determine the rank of the interference DMRS, and the port and scrambling identity of each of the interference DMRS layers. ## Claims ### Claim 1 A method for characterizing a hypothesized interference demodulation reference signal (DMRS) component of a received signal, the method comprising: removing, from the received signal, a serving data signal, to form a diminished signal; and determining, from the diminished signal, whether the hypothesized interference DMRS component is present in the received signal. ### Claim 2 (depends on 1) The method of claim 1, wherein the removing of the serving data signal from the received signal comprises utilizing hard output from a detector/decoder to represent the serving data signal. ### Claim 3 (depends on 1) The method of claim 1, wherein the removing of the serving data signal from the received signal comprises utilizing soft output from a detector/decoder to represent the serving data signal. ### Claim 4 (depends on 1) The method of claim 1, further comprising determining a rank of the hypothesized interference DMRS component, wherein the determining of the rank of the hypothesized interference DMRS component comprises calculating four power levels within a resource block of the diminished signal, each of the four power levels being a power level for a respective one of four interference DMRS candidates, each of the four interference DMRS candidates having a different combination of port number and scrambling identity, each of the port numbers being 7 or 8, and each of the scrambling identities being 0 or 1. ### Claim 5 (depends on 4) The method of claim 4, wherein the determining of the rank of the hypothesized interference DMRS component further comprises: calculating a first testing ratio as the ratio of: the power level of the other DMRS candidate, of the four interference DMRS candidates, having the same scrambling identity as the DMRS candidate, of the four interference DMRS candidates, having the greatest one of the four power levels; to the greatest one of the four power levels; determining that the rank of the hypothesized interference DMRS component is 2 when the first testing ratio exceeds a first threshold; and determining that the rank of the hypothesized interference DMRS component is 1 otherwise. ### Claim 6 (depends on 5) The method of claim 5, wherein the determining of whether the hypothesized interference DMRS component is present in the received signal comprises, when the determined rank is 1: calculating a second testing ratio as the ratio of: the greatest one of the four power levels; to the difference between: the total of the four power levels; and the greatest one of the four power levels; and determining that the hypothesized interference DMRS component is present when the second testing ratio exceeds a second threshold. ### Claim 7 (depends on 6) The method of claim 6, further comprising determining a port number and a scrambling identity of each layer of the hypothesized interference DMRS component, wherein the determining of the port number and the scrambling identity of each layer of the hypothesized interference DMRS component comprises determining the port number and the scrambling identity to be those of the DMRS candidate having the greatest power. ### Claim 8 (depends on 5) The method of claim 5, wherein the determining of whether the hypothesized interference DMRS component is present in the received signal comprises, when the determined rank is 2: calculating a third testing ratio as the ratio of: the sum of: the greatest one of the four power levels; and the power level of the other DMRS candidate having the same scrambling identity as the DMRS candidate having the greatest one of the four power levels; and the difference between: the total of the four power levels; and the sum of: the greatest one of the four power levels; and the power level of the other DMRS candidate having the same scrambling identity as the DMRS candidate having the greatest one of the four power levels; and determining that the hypothesized interference DMRS component is present when the third testing ratio exceeds a third threshold. ### Claim 9 (depends on 8) The method of claim 8, wherein the determining of the port number and the scrambling identity of each layer of the hypothesized interference DMRS component comprises: determining the port number and the scrambling identity of a first layer of the hypothesized interference DMRS component to be those of the DMRS candidate having the greatest power; and determining the port number and the scrambling identity of a second layer of the hypothesized interference DMRS component to be those of the other DMRS candidate having the same scrambling identity as the DMRS candidate having the greatest power. ### Claim 10 A method for characterizing a hypothesized interference demodulation reference signal (DMRS) component of a received signal, the method comprising: removing, from the received signal, one of: a serving data signal and a serving DMRS, to form a diminished signal; determining, from the diminished signal, whether the hypothesized interference DMRS component is present in the received signal; and determining a rank of the hypothesized interference DMRS component. ### Claim 11 (depends on 10) The method of claim 10, wherein the removing of the one of a serving data signal and a serving DMRS from the received signal comprises: determining whether a serving signal component of the received signal includes the serving DMRS; removing the serving DMRS from the received signal when it is determined that the serving signal component of the received signal includes the serving DMRS; and removing the serving data signal from the received signal otherwise. ### Claim 12 (depends on 11) The method of claim 11, wherein the removing of the serving data signal from the received signal comprises utilizing hard output from a detector/decoder to represent the serving data signal. ### Claim 13 (depends on 11) The method of claim 11, wherein the removing of the serving data signal from the received signal comprises utilizing soft output from a detector/decoder to represent the serving data signal. ### Claim 14 (depends on 10) The method of claim 10, wherein the determining of the rank of the hypothesized interference DMRS component comprises calculating four power levels within a resource block of the diminished signal, each of the four power levels being a power level for a respective one of four interference DMRS candidates, each of the four interference DMRS candidates having a different combination of port number and scrambling identity, each of the port numbers being 7 or 8, and each of the scrambling identities being 0 or 1. ### Claim 15 (depends on 14) The method of claim 14, wherein the determining of the rank of the hypothesized interference DMRS component further comprises: calculating a first testing ratio as the ratio of: the power level of the other DMRS candidate, of the four interference DMRS candidates, having the same scrambling identity as the DMRS candidate, of the four interference DMRS candidates, having the greatest one of the four power levels; to the greatest one of the four power levels; determining that the rank of the hypothesized interference DMRS component is 2 when the first testing ratio exceeds a first threshold; and determining that the rank of the hypothesized interference DMRS component is 1 otherwise. ### Claim 16 (depends on 15) The method of claim 15, wherein the determining of whether the hypothesized interference DMRS component is present in the received signal comprises, when the determined rank is 1: calculating a second testing ratio as the ratio of: the greatest one of the four power levels; to the difference between: the total of the four power levels; and the greatest one of the four power levels; and determining that the hypothesized interference DMRS component is present when the second testing ratio exceeds a second threshold. ### Claim 17 (depends on 16) The method of claim 16, further comprising determining a port number and a scrambling identity of each layer of the hypothesized interference DMRS component, wherein the determining of the port number and the scrambling identity of each layer of the hypothesized interference DMRS component comprises determining the port number and the scrambling identity to be those of the DMRS candidate having the greatest power. ### Claim 18 (depends on 15) The method of claim 15, wherein the determining of whether the hypothesized interference DMRS component is present in the received signal comprises, when the determined rank is 2: calculating a third testing ratio as the ratio of: the sum of: the greatest one of the four power levels; and the power level of the other DMRS candidate having the same scrambling identity as the DMRS candidate having the greatest one of the four power levels; and the difference between: the total of the four power levels; and the sum of: the greatest one of the four power levels; and the power level of the other DMRS candidate having the same scrambling identity as the DMRS candidate having the greatest one of the four power levels; and determining that the hypothesized interference DMRS component is present when the third testing ratio exceeds a third threshold. ### Claim 19 (depends on 18) The method of claim 18, wherein the determining of the port number and the scrambling identity of each layer of the hypothesized interference DMRS component comprises: determining the port number and the scrambling identity of a first layer of the hypothesized interference DMRS component to be those of the DMRS candidate having the greatest power; and determining the port number and the scrambling identity of a second layer of the hypothesized interference DMRS component to be those of the other DMRS candidate having the same scrambling identity as the DMRS candidate having the greatest power. ### Claim 20 A system for characterizing a hypothesized interference demodulation reference signal (DMRS) component of a received signal, the system comprising a processing circuit configured to: remove a serving data signal from the received signal, to form a diminished signal; and determine whether the hypothesized interference DMRS component is present in the received signal.