# US 2021/0243803 A1 · Systems and methods for channel access > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243803 A1 - Document ID: US20210243803A1 - Status: Published application - Kind: A1 - Application number: 17/149,500 - Filed: 2021-01-14 - Published: 2021-08-05 - Earliest claimed: 2018-07-20 - Assignees: Zte Corporation - Applicants: Zte Corporation - Inventors: Hanqing XU; Yajun ZHAO; Xincai LI; Ling YANG - Web page: https://patentgrep.com/patent/US20210243803A1 ## CPC - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 16/14: Spectrum sharing arrangements {between different networks} - 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)} - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a 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 A system and method for channel access in licensed and unlicensed spectrums are disclosed herein. In one embodiment, a method performed by a communication node, includes: detection of an idle channel associated with a communication device after performance of a channel access procedure; transmitting an initial signal after the detection of the idle channel, wherein the initial signal configures a communication device to start detecting a control channel; and transmitting a control signal using the control channel to the communication device after the transmitting the initial signal. ## Claims ### Claim 1 A method performed by a communication node, the method comprising: detection of an idle channel associated with a communication device after performance of a channel access procedure; transmitting an initial signal after the detection of the idle channel, wherein the initial signal configures a communication device to start detecting a control channel; and transmitting a control signal using the control channel to the communication device after the transmitting the initial signal. ### Claim 2 (depends on 1) The method of claim 1, further comprising: transmitting the initial signal at a predefined symbol, of a slot or subframe, after the detection of the idle channel; or transmitting the initial signal on a symbol preceding a control channel detection pattern associated with the control channel. ### Claim 3 (depends on 1) The method of claim 1, wherein the initial signal is continuous with the control signal in a time domain; or wherein the initial signal is discontinuous with the control signal in a time domain; or wherein the initial signal is part of a set of initial signals and wherein the method further comprises transmitting the set of initial signals on respective beams within a round of beam scanning, wherein preferably each individual initial signal of the set of initial signals comprises different information. ### Claim 4 (depends on 1) The method of claim 1, further comprising: indicating a pattern to the communication device; and transmitting the initial signal according to the pattern after the detection of the idle channel. ### Claim 5 (depends on 1) The method of claim 1, wherein the method further comprises: transmitting the initial signal on a predetermined beam. ### Claim 6 (depends on 1) The method of claim 1, wherein the initial signal and the control channel are transmitted in an unlicensed spectrum. ### Claim 7 (depends on 1) The method of claim 1, wherein the initial signal is at least one of: a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a demodulation reference signal (DMRS), a channel state information-reference signal (CSI-RS), a phase tracking reference signal (PTRS), or a sounding reference signal (SRS). ### Claim 8 (depends on 1) The method of claim 1, wherein the initial signal is not transmitted when the initial signal overlaps in a time domain and a frequency domain with at least one of: a sounding signal (SS); a physical broadcast channel (PBCH); a control-resource set (CORESET) used for remaining minimum system information (RMSI); or a random access channel (RACH) occasion. ### Claim 9 (depends on 1) The method of claim 1, wherein the transmitting the initial signal is performed once per occupation period. ### Claim 10 A method performed by a communication device, the method comprising: detecting an initial signal from a communication node on an idle channel, wherein the initial signal configures the communication device to start detecting a control channel; and detecting a control signal on the control channel from the communication node in accordance with the initial signal. ### Claim 11 (depends on 10) The method of claim 10, wherein the control channel comprises at least one of: a physical downlink control channel; a control-resource set; or a search space, wherein preferably the search space is in a time and frequency domain. ### Claim 12 (depends on 10) The method of claim 10, further comprising: detecting the control signal at a first time differently than detecting the control signal at a second time; or detecting a first control signal at a first time and detecting a second control signal at a second time, wherein the control signal comprises the first control signal and the second control signal. ### Claim 13 (depends on 10) The method of claim 10, wherein the control channel comprises at least one of a Type0-PDCCH, a Type0A-PDCCH, a Type1-PDCCH, a Type2-PDCCH, or a Type3-PDCCH; or wherein the initial signal configures the communication device to camp on an identified resource. ### Claim 14 (depends on 10) The method of claim 10, wherein the initial signal comprises at least one of: a cell identifier; a group identifier; a system frame number identifier; a timing relationship between the initial signal and the control channel; a subcarrier spacing; an initial signal number; a block number index; information characterizing a control channel detection pattern; or information identifying whether the communication node is a sender or receiver of a subsequent communication; or wherein the initial signal identifies multiple control channel detection patterns for use by the communication device; or wherein control channel detection patterns are produced by the communication node. ### Claim 15 (depends on 1) A computing device comprising: at least one processor configured to carry out the method of claim 1. ### Claim 16 (depends on 2) A computing device comprising: at least one processor configured to carry out the method of claim 2. ### Claim 17 (depends on 3) A computing device comprising: at least one processor configured to carry out the method of claim 3. ### Claim 18 (depends on 4) A computing device comprising: at least one processor configured to carry out the method of claim 4. ### Claim 19 (depends on 10) A computing device comprising: at least one processor configured to carry out the method of claim 10. ### Claim 20 (depends on 12) A computing device comprising: at least one processor configured to carry out the method of claim 12.