# US 2014/0192786 A1 · DM RS Based LTE Downlink Physical Layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192786 A1 - Document ID: US20140192786A1 - Status: Published application - Kind: A1 - Application number: 14/131,025 - Filed: 2011-07-06 - Published: 2014-07-10 - Earliest claimed: 2011-07-06 - Assignees: Nokia Solutions and Networks Oy - Inventors: Peter Skov; Xiaoyi Wang; De Shan Miao - Web page: https://patentgrep.com/patent/US20140192786A1 ## CPC - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 56/0005: {synchronizing of arrival of multiple uplinks} - H04W 56/0015: {one node acting as a reference for the others} - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04L 27/2601: {Multicarrier modulation systems} - H04W 74/0833: Random access procedures, e.g. with 4-step access - 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 It is provided an apparatus, including synchronizing means adapted to synchronize with a cell of a cellular communication system based on a synchronization signal and to obtain a cell identification of the cell; receiving means adapted to receive a symbol only on one or more subcarriers and subframes which carry at least one symbol of a physical broadcast channel; first obtaining means adapted to obtain a common demodulation reference symbol based on the cell identification and the received symbol; demodulating means adapted to demodulate a signal received on the physical broadcast channel based on the common demodulation reference symbol; user equipment means adapted to provide a user equipment functionality of the communication system. ## Claims ### Claim at position 1 1-31. (canceled) ### Claim 32 Apparatus, comprising synchronizing means adapted to synchronize with a cell of a cellular communication system based on a synchronization signal and to obtain a cell identification of the cell; receiving means adapted to receive a symbol only on one or more subcarriers and subframes which carry at least one symbol of a physical broadcast channel; first obtaining means adapted to obtain a common demodulation reference symbol based on the cell identification and the received symbol; demodulating means adapted to demodulate a signal received on the physical broadcast channel based on the common demodulation reference symbol; user equipment means adapted to provide a user equipment functionality of the communication system. ### Claim 33 (depends on 32) Apparatus according to claim 32, wherein the demodulating means is further adapted to demodulate a signal received on a physical downlink control channel based on the common demodulation reference symbol; or further adapted to demodulate a signal received on a physical downlink control channel based on a specific demodulation reference symbol, wherein the apparatus comprises second obtaining means adapted to obtain a specific demodulation reference symbol based on a specific identification received from the cell, wherein ### Claim 34 (depends on 33) Apparatus according to claim 33, wherein the demodulating means is adapted to demodulate a signal received on a physical downlink shared channel allocated in a subframe together with the physical downlink control channel based on the specific demodulation reference symbol. ### Claim 35 (depends on 32) Apparatus according to claim 32, further comprising RACH response detecting means adapted to detect a random access channel response signal received on a physical downlink shared channel; the demodulating means is further adapted to demodulate the physical downlink shared channel and a physical downlink control channel based on the common demodulation reference symbol to obtain a demodulated RACH response signal. ### Claim 36 (depends on 32) Apparatus according to claim 32, further comprising preamble providing means adapted to provide a preamble including a PRACH resource index; RACH response detecting means adapted to detect a random access channel response signal received on a physical downlink shared channel; third obtaining means adapted to obtain a specific RACH demodulation reference symbol based on the PRACH resource index; wherein the demodulating means is further adapted to demodulate the physical downlink shared channel and a physical downlink control channel based on the specific RACH demodulation reference symbol. ### Claim 37 Apparatus, comprising base station means adapted to provide a base station functionality in a cell of a cellular communication system; broadcasting means adapted to broadcast a common demodulation reference signal to all user equipments in the cell, wherein the common demodulation reference signal is based on a cell identification of the cell, and the common demodulation reference symbol is transmitted only on one or more subcarriers and in subframes which carry at least one symbol of a physical broadcast channel. ### Claim 38 (depends on 37) Apparatus according to claim 37, further comprising specific demodulation reference symbol providing means adapted to provide a specific demodulation reference symbol based on an identification specification specific for one of the user equipments, and physical downlink control channel modulating means adapted to modulate a symbol of a physical downlink control channel to the one of the user equipments based on the specific demodulation reference symbol. ### Claim 39 (depends on 37) Apparatus according to claim 37, further comprising RACH response providing means adapted to provide a RACH response message in response to a received preamble, wherein the RACH response message is provided in a physical downlink shared channel allocated with a physical downlink control channel and modulated based on the common demodulation reference symbol. ### Claim 40 (depends on 37) Apparatus according to claim 37, further comprising obtaining means adapted to obtain a RACH demodulation reference symbol based on a PRACH resource index comprised in a preamble received from one of the user equipments; RACH response providing means adapted to provide a RACH response message in response to the preamble; and modulating means adapted to modulate the physical downlink shared channel to the one of the user equipments based on the RACH demodulation reference symbol, wherein the physical downlink shared channel comprises the RACH response message. ### Claim 41 Method, comprising synchronizing with a cell of a cellular communication system based on a synchronization signal to obtain a cell identification of the cell; receiving a symbol only on one or more subcarriers and subframes which carry at least one symbol of a physical broadcast channel; obtaining a common demodulation reference symbol based on the cell identification and the received symbol; demodulating a signal received on the physical broadcast channel based on the common demodulation reference symbol; providing a user equipment functionality of the communication system. ### Claim 42 (depends on 41) Method according to claim 41, further comprising demodulating a signal received on a physical downlink control channel based on the common demodulation reference symbol; or demodulating a signal received on a physical downlink control channel based on a specific demodulation reference symbol, wherein the method further comprises obtaining a specific demodulation reference symbol based on a specific identification received from the cell. ### Claim 43 (depends on 42) Method according to claim 42, further comprising demodulating a signal received on a physical downlink shared channel allocated in a subframe together with the physical downlink control channel based on the specific demodulation reference symbol. ### Claim 44 (depends on 41) Method according to claim 41, further comprising detecting a random access channel response signal received on a physical downlink shared channel; and demodulating the physical downlink shared channel and a physical downlink control channel based on the common demodulation reference symbol to obtain a demodulated RACH response signal. ### Claim 45 Method, comprising providing a base station functionality in a cell of a cellular communication system; broadcasting a common demodulation reference signal to all user equipments in the cell, wherein the common demodulation reference signal is based on a cell identification of the cell, and the common demodulation reference symbol is transmitted only on one or more subcarriers and in subframes which carry at least one symbol of a physical broadcast channel. ### Claim 46 (depends on 45) Method according to claim 45, further comprising providing a specific demodulation reference symbol based on an identification specification specific for one of the user equipments, and modulating a symbol of a physical downlink control channel to the one of the user equipments based on the specific demodulation reference symbol. ### Claim 47 (depends on 46) Method according to claim 46, further comprising modulating a physical downlink shared channel to the one of the user equipments based on the specific demodulation reference symbol, wherein the physical downlink shared channel is allocated in a subframe together with the physical downlink control channel to the one of the user equipments. ### Claim 48 (depends on 45) Method according to claim 45, further comprising obtaining a RACH demodulation reference symbol based on a PRACH resource index comprised in a preamble received from one of the user equipments; providing a RACH response message in response to the preamble; and modulating the physical downlink shared channel to the one of the user equipments based on the RACH demodulation reference symbol, wherein the physical downlink shared channel comprises the RACH response message. ### Claim 49 (depends on 41) A computer program product including a program comprising software code portions being arranged, when run on a processor of an apparatus, to perform the method according to claim 41.