# US 2020/0288278 A1 · Method and apparatus for transmitting and receiving data > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0288278 A1 - Document ID: US20200288278A1 - Status: Published application - Kind: A1 - Application number: 16/880,521 - Filed: 2020-05-21 - Published: 2020-09-10 - Earliest claimed: 2010-10-06 - Assignees: Unwired Planet International Limited - Applicants: Unwired Planet International Limited - Inventors: Jin Kyu HAN; Youn Sun KIM - Web page: https://patentgrep.com/patent/US20200288278A1 ## CPC - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04L 5/0058: {Allocation criteria} - H04L 27/2602: {Signal structure} - H04L 27/2603: {Signal structure ensuring backward compatibility with legacy system} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - 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) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract An apparatus and method are provided for receiving data by a first transceiver. The method includes receiving information for at least one transmission mode through higher layer signaling from a second transceiver; and receiving data on a first sub-frame based on a first demodulation reference signal (DMRS), if the at least one transmission mode is transmission mode 9 or transmission mode 10 and the first sub-frame is a multimedia broadcast multicast service single frequency network (MBSFN) sub-frame. ## Claims ### Claim 1 A user equipment comprising: a receiver configured to receive upper signaling and a current sub-frame; a controller configured to determine, based on the upper layer signaling, whether to use a common reference signal (CRS) or a demodulation reference signal (DM-RS) as a reference signal in channel estimation for demodulation. ### Claim 2 (depends on 1) The user equipment of claim 1, wherein the controller is further configured to perform the channel estimation in accordance with the reference signal. ### Claim 3 (depends on 1) The user equipment of claim 1, wherein the controller is further configured to determine, based on the upper layer signaling, whether the current sub-frame is an LTE-A sub-frame ### Claim 4 (depends on 3) The user equipment of claim 3, wherein the controller is configured to determine whether the current sub-frame is the LTE-A sub-frame or a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) sub-frame. ### Claim 5 (depends on 1) The user equipment of claim 1, wherein: when the controller determines that the current sub-frame is an LTE-A sub-frame, the controller causes channel estimation using the reference signal, the reference signal being determined from a physical downlink control channel (PDCCH) according to a transmission mode for the LTE-A sub-frame and acquired DCI information; and when the controller determines that the current sub-frame is not the LTE-A sub-frame, the controller causes channel estimation according to a transmission mode which is set in a received mode information element and which indicates that the common reference signal (CRS) is to be used for channel estimation. ### Claim 6 (depends on 1) The user equipment of claim 1, wherein the controller is further configured to determine how many demodulation reference signals (DM-RS s) are to be estimated when the demodulation reference signal (DM-RS) is used for channel estimation. ### Claim 7 (depends on 1) The user equipment of claim 1, wherein the controller is further configured to determine which downlink control information (DCI) format is used. ### Claim 8 (depends on 7) The user equipment of claim 7, wherein the controller is further configured to determine, based on DCI format, in which resource a data channel signal is received. ### Claim 9 A method in a user equipment comprising: receiving upper signaling and a current sub-frame; using a controller to determine, based on the upper layer signaling, whether to use a common reference signal (CRS) or a demodulation reference signal (DM-RS) as a reference signal in channel estimation for demodulation. ### Claim 10 (depends on 9) The method claim 9, further comprising performing the channel estimation in accordance with the reference signal. ### Claim 11 (depends on 9) The method claim 9, further comprising determining, based on the upper layer signaling, whether the current sub-frame is an LTE-A sub-frame ### Claim 12 (depends on 11) The method of claim 11, further comprising determining whether the current sub-frame is the LTE-A sub-frame or a Multimedia Broadcast Multi cast Service Single Frequency Network (MBSFN) sub-frame. ### Claim 13 (depends on 11) The method of claim 11, further comprising: when the current sub-frame is an LTE-A sub-frame, using the controller to cause channel estimation using the reference signal, the reference signal being determined from a physical downlink control channel (PDCCH) according to a transmission mode for the LTE-A sub-frame and acquired DCI information; and when the current sub-frame is not the LTE-A sub-frame, using the controller to cause channel estimation according to a transmission mode which is set in a received mode information element and which indicates that the common reference signal (CRS) is to be used for channel estimation. ### Claim 14 (depends on 9) The method claim 9, further comprising determining how many demodulation reference signals (DM-RSs) are to be estimated when the demodulation reference signal (DM-RS) is used for channel estimation. ### Claim 15 (depends on 9) The method claim 9, further comprising determining which downlink control information (DCI) format is used.