# US 2018/0324837 A1 · Uplink Spectrum Efficiency > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324837 A1 - Document ID: US20180324837A1 - Status: Published application - Kind: A1 - Application number: 16/037,133 - Filed: 2018-07-17 - Published: 2018-11-08 - Earliest claimed: 2013-01-16 - Assignees: InterDigital Patent Holdings, Inc. - Applicants: Interdigital Patent Holdings, Inc. - Inventors: J. Patrick Tooher; Paul Marinier; Marian Rudolf - Web page: https://patentgrep.com/patent/US20180324837A1 ## CPC - H04L 27/2602: {Signal structure} - 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 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/1268: of uplink data flows - H04L 27/2603: {Signal structure ensuring backward compatibility with legacy system} - H04L 27/26035: {Maintenance of orthogonality, e.g. for signals exchanged between cells or users, or by using covering codes or sequences (using different training sequence per antenna H04B7/0684; code allocation H04J13/16)} - 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 Methods and systems are disclosed for reducing control signaling in uplink transmissions. A device, such as a wireless transmit/receive unit, may determine to use a demodulation reference signal (DM-RS) transmission schedule out of a plurality of DM-RS transmission schedules. The DM-RS transmission schedule may be characterized by a DM-RS transmission being mapped to a single orthogonal frequency-division multiplexing (OFDM) symbol per subframe of a data stream. The DM-RS transmission schedule may be characterized by a DM-RS transmission being mapped to a first subset of subcarriers of an OFDM symbol of a subframe of a data stream and Physical Uplink Shared Channel (PUSCH) transmission or Physical Uplink Control Channel (PUCCH) control information being mapped to a second set of subcarriers of the OFDM symbol. The first set of subcarriers may be different than the second set of subcarriers. The data stream may be transmitted according to the DM-RS transmission schedule. ## Claims ### Claim at position 1 1-20. (canceled) ### Claim 21 A method implemented in a wireless transmit receive unit (WTRU), the method comprising: receiving a radio resource control (RRC) configuration indicating a plurality of potential demodulation reference signal (DM-RS) transmission schedules associated with a Physical Uplink Shared Channel (PUSCH); receiving downlink control information (DCI) associated with a PUSCH Physical Uplink Shared Channel (PUSCH) transmission, the PUSCH transmission to be performed over a plurality of OFDM symbols; determining, based at least on the DCI and the RRC configuration, which one or multiple OFDM symbols of the plurality of OFDM symbols should be used to transmit DM-RS for the PUSCH transmission; and transmitting DM-RS for the PUSCH transmission in the one or multiple OFDM symbols. ### Claim 22 (depends on 21) The method of claim 21, wherein the potential DM-RS transmission schedules are associated with different time-domain positions of DM-RSs. ### Claim 23 (depends on 21) The method of claim 21, wherein the potential DM-RS transmission schedules are associated with respective numbers of OFDM symbols used for transmitting DM-RSs. ### Claim 24 (depends on 21) The method of claim 21, wherein the determining of which one or multiple OFDM symbols should be used to transmit DM-RS for the PUSCH transmission is based at least on a format of the DCI. ### Claim 25 (depends on 21) The method of claim 21, wherein the determining of which one or multiple OFDM symbols should be used to transmit DM-RS for the PUSCH transmission is based further on a duration of the PUSCH transmission. ### Claim 26 (depends on 21) The method of claim 21, wherein the RRC configuration further indicates the position of a first OFDM symbol within a slot to be used for DM-RS transmission. ### Claim 27 (depends on 21) The method of claim 21, wherein the DCI is associated with an uplink grant associated with the PUSCH transmission. ### Claim 28 (depends on 21) The method of claim 21, wherein at least one of the potential DM-RS transmission schedules is associated with using a single OFDM symbol of a slot for DM-RS transmission. ### Claim 29 A wireless transmit receive unit (WTRU), comprising: a processor configured to: receive a radio resource control (RRC) configuration indicating a plurality of potential demodulation reference signal (DM-RS) transmission schedules associated with a Physical Uplink Shared Channel (PUSCH); receive downlink control information (DCI) associated with a PUSCH Physical Uplink Shared Channel (PUSCH) transmission, the PUSCH transmission to be performed over a plurality of OFDM symbols; determine, based at least on the DCI and the RRC configuration, which one or multiple OFDM symbols of the plurality of OFDM symbols should be used to transmit DM-RS for the PUSCH transmission; and transmit DM-RS for the PUSCH transmission in the one or multiple OFDM symbols. ### Claim 30 (depends on 29) The WTRU of claim 29, wherein the potential DM-RS transmission schedules are associated with different time-domain positions of DM-RSs. ### Claim 31 (depends on 29) The WTRU of claim 29, wherein the potential DM-RS transmission schedules are associated with respective numbers of OFDM symbols used for transmitting DM-RSs. ### Claim 32 (depends on 29) The WTRU of claim 29, wherein the processor is configured to determine which one or multiple OFDM symbols should be used to transmit DM-RS for the PUSCH transmission based at least on a format of the DCI. ### Claim 33 (depends on 29) The WTRU of claim 29, wherein the processor is configured to determine which one or multiple OFDM symbols should be used to transmit DM-RS for the PUSCH transmission based further on a duration of the PUSCH transmission. ### Claim 34 (depends on 29) The WTRU of claim 29, wherein the RRC configuration further indicates the position of a first OFDM symbol within a slot to be used for DM-RS transmission. ### Claim 35 (depends on 29) The WTRU of claim 29, wherein the DCI is associated with an uplink grant for the PUSCH transmission. ### Claim 36 (depends on 29) The WTRU of claim 29, wherein at least one of the potential DM-RS transmission schedules is associated with using a single OFDM symbol of a slot for DM-RS transmission.