# US 11,115,974 B2 · Resolving colliding signals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,974 B2 - Document ID: US11115974B2 - Status: Granted - Kind: B2 - Application number: 16/834,769 - Filed: 2020-03-30 - Published: 2020-07-16 - Granted: 2021-09-07 - Earliest claimed: 2015-04-09 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Yufei Blankenship; Mattias Frenne - Web page: https://patentgrep.com/patent/US11115974B2 ## CPC - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04L 5/0044: {Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH} - H04L 5/0096: {Indication of changes in allocation} - H04W 4/70: Services for machine-to-machine communication [M2M] or machine type communication [MTC] - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Systems and methods are disclosed herein that relate to transmitting and receiving a transmission when there is a collision between the transmission and reserved resource elements. In some embodiments, a radio access node for a cellular communications network is disclosed, wherein the radio access node comprises a transceiver, a processor, and memory storing instructions executable by the processor whereby the radio access node is operable to transmit, via the transceiver, a downlink transmission to a wireless device using one or more Physical Resource Blocks (PRBs) that comprise reserved Resource Elements (REs) by puncturing the downlink transmission at positions of the reserved REs. In some embodiments, the downlink transmission is an Enhanced Physical Downlink Control Channel (EPDCCH) transmission or a Physical Downlink Shared Channel (PDSCH) transmission. Further, in some embodiments, the reserved REs are REs utilized for one or more CSI-RSs. ## Claims ### Claim 1 A method of operation of a radio access node in a cellular communications network, comprising: transmitting a downlink transmission to a wireless device using one or more Physical Resource Blocks, PRBs, that comprise reserved Resource Elements, REs, by first mapping the downlink transmission to REs in the one or more PRBs and then mapping reference symbols to a subset of the REs in the one or more PRBs that are the reserved REs such that the downlink transmission is punctured by the reference symbols at positions of the reserved REs, the downlink transmission being a physical downlink channel transmission. ### Claim 2 (depends on 1) The method of claim 1, wherein transmitting the downlink transmission comprises transmitting the downlink transmission at a reduced code rate when the downlink transmission is punctured by the reference symbols at positions of the reserved REs. ### Claim 3 (depends on 1) The method of claim 1 wherein the physical downlink channel transmission is a Physical Downlink Shared Channel, PDSCH, transmission. ### Claim 4 (depends on 3) The method of claim 3 wherein the reference symbols are Channel State Information Reference Signal, CSI-RS, reference symbols. ### Claim 5 (depends on 1) The method of claim 1 wherein the physical downlink channel transmission is an Enhanced Physical Downlink Control Channel, EPDCCH, transmission. ### Claim 6 (depends on 5) The method of claim 5 wherein the reference symbols are Channel State Information Reference Signal, CSI-RS, reference symbols. ### Claim 7 A method of operation of a wireless device in a cellular communications network, comprising: receiving a downlink transmission from a radio access node on one or more Physical Resource Blocks, PRBs, based on an assumption by the wireless device that the downlink transmission is first mapped to Resource Elements, REs, in one or more PRBs and then reference symbols are mapped to a subset of the REs in the one or more PRBs that are reserved REs, such that the downlink transmission is punctured by the reference symbols at positions of the reserved REs, wherein the downlink transmission is a physical downlink channel transmission. ### Claim 8 (depends on 7) The method of claim 7, wherein receiving the downlink transmission comprises receiving the downlink transmission at a reduced code rate when the downlink transmission is punctured by the reference symbols at positions of the reserved REs. ### Claim 9 (depends on 7) The method of claim 7 wherein the physical downlink channel transmission is a Physical Downlink Shared Channel, PDSCH, transmission. ### Claim 10 (depends on 9) The method of claim 9 wherein the reference symbols are Channel State Information Reference Signal, CSI-RS, reference symbols. ### Claim 11 (depends on 7) The method of claim 7 wherein the physical downlink channel transmission is an Enhanced Physical Downlink Control Channel, EPDCCH, transmission. ### Claim 12 (depends on 11) The method of claim 11 wherein the reference symbols are Channel State Information Reference Signal, CSI-RS, reference symbols. ### Claim 13 A method of operation of a wireless device in a cellular communications network, comprising: obtaining an indicator that is indicative of whether reserved Resource Elements, REs, are present in a subframe in which a physical downlink channel transmission is transmitted from a radio access node to the wireless device; determining reserved REs are present in the subframe based on the indicator; and upon determining that reserved REs are present in the subframe, attempting reception of the physical downlink channel transmission based on the determination that reserved REs are present in the subframe. ### Claim 14 (depends on 13) The method of claim 13 wherein the indicator comprises time-domain information regarding the presence of reserved REs. ### Claim 15 (depends on 13) The method of claim 13 wherein the indicator comprises information that indicates which REs are reserved REs. ### Claim 16 (depends on 13) The method of claim 13 further comprising, upon determining that reserved REs are not present in the subframe, attempting reception of the physical downlink channel transmission based on an assumption that reserved REs are not present in the subframe. ### Claim 17 (depends on 13) The method of claim 13 wherein the physical downlink channel transmission is an Enhanced Physical Downlink Control Channel, EPDCCH, transmission. ### Claim 18 (depends on 13) The method of claim 13 wherein the reserved REs are REs utilized for one or more Channel State Information Reference Signals, CSI-RSs. ### Claim 19 (depends on 13) The method of claim 13 wherein the physical downlink channel transmission is a Physical Downlink Shared Channel, PDSCH, transmission. ### Claim 20 (depends on 19) The method of claim 19 wherein the reserved REs are REs utilized for one or more Channel State Information Reference Signals, CSI-RSs. ### Claim 21 (depends on 13) The method of claim 13 wherein obtaining the indicator comprises receiving and storing a configuration of reserved REs in multiple subframes, including the subframe, from received system information, the configuration of reserved REs in the multiple subframes comprising the indicator that is indicative of whether reserved REs are present in the subframe. ### Claim 22 (depends on 21) The method of claim 21 wherein the wireless device is a Machine Type Communication, MTC, device, and the received system information is a MTC Master Information Block, MTC-MIB. ### Claim 23 (depends on 21) The method of claim 21 wherein the wireless device is a Machine Type Communication, MTC, device, and the received system information is a MTC Secondary Information Block, MTC-SIB. ### Claim 24 (depends on 13) The method of claim 13 wherein attempting reception of the physical downlink channel transmission based on an assumption that reserved REs are present in the subframe comprises de-mapping a plurality of REs corresponding to the physical downlink channel transmission from one or more Physical Resource Blocks, PRBs, in the subframe. ### Claim 25 (depends on 13) The method of claim 13 wherein attempting reception of the physical downlink channel transmission based on an assumption that reserved REs are present in the subframe comprises ignoring the reserved REs during reception of the physical downlink channel transmission.