# US 10,375,581 B2 · Method and system for radar detection in shared spectrum > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,375,581 B2 - Document ID: US10375581B2 - Status: Granted - Kind: B2 - Application number: 15/869,925 - Filed: 2018-01-12 - Published: 2018-05-17 - Granted: 2019-08-06 - Earliest claimed: 2018-01-12 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Gary Boudreau; Christopher Richards; Virgil Cimpu - Web page: https://patentgrep.com/patent/US10375581B2 ## CPC - H04W 16/14: Spectrum sharing arrangements {between different networks} - G01S 7/021: {Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals} - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04W 74/0816: with collision avoidance - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract The present disclosure relates to a method and system in a wireless network for radar detection in certain bands e.g. bands normally used for unlicensed access. In one broad aspect, a method is provided for a network node configured to control wireless transmissions in a frequency band also used for radar transmissions. In that method, the network node controls the wireless transmissions using a transmission cycle pattern defined by a transmit on time and a transmit off time. The method includes after a wireless transmission during the transmit-on time of a first transmission cycle, detecting, during the transmit-off time of the first transmission cycle, at least one radar pulse in the frequency band and extending the transmit off time of a second transmission cycle based on the at least one radar pulse detected. Advantageously, in some implementations, extending the transmit off time when one or more radar pulses are detected provides more time to detect a larger number of pulses which as a result, may improve radar detection accuracy. ## Claims ### Claim 1 A method for a network node configured to control wireless transmissions between the network node and wireless devices in a wireless network using a transmission cycle pattern defined by a transmit on time and a transmit off time, the wireless transmissions occurring in a frequency band used for transmissions of higher priority repetitive signals or pulses, the method comprising: after a wireless transmission during a transmit on time of a first transmission cycle, detecting, during a transmit off time of the first transmission cycle, at least one higher priority repetitive signal or pulse in the frequency band; and extending the transmit off time of the first transmission cycle and/or at least one subsequent transmission cycle based on the at least one higher priority repetitive signal or pulse detected. ### Claim 2 (depends on 1) The method of claim 1 wherein the at least one higher priority repetitive signal or pulse detected in the frequency band is at least one radar pulse detected in the frequency band such that detecting the at least one higher priority repetitive signal or pulse in the frequency band comprises detecting, during the transmit off time of the first transmission cycle, the at least one radar pulse in the frequency band. ### Claim 3 (depends on 2) The method of claim 2 wherein extending the transmit off time of the first transmission cycle and/or the at least one subsequent transmission cycle comprises extending the transmit off time of the first transmission cycle. ### Claim 4 (depends on 2) The method of claim 2 wherein extending the transmit off time of the first transmission cycle and/or the at least one subsequent transmission cycle comprises extending the transmit off time of the at least one subsequent transmission cycle. ### Claim 5 (depends on 2) The method of claim 2 wherein extending the transmit off time of the first transmission cycle and/or the at least one subsequent transmission cycle comprises extending the transmit off time of the first transmission cycle and the transmit off time of the at least one subsequent transmission cycle. ### Claim 6 (depends on 2) The method of claim 2 wherein extending the transmit off time of the first transmission cycle and/or the at least one subsequent transmission cycle comprises one of reducing the transmit on time of the first transmission cycle and/or the at least one subsequent transmission cycle, reducing a duty cycle of the first transmission cycle and/or the at least one subsequent transmission cycle, and extending a transmission cycle period for the first transmission cycle and/or the at least one subsequent transmission cycle. ### Claim 7 (depends on 2) The method of claim 2 further comprising detecting a number of radar pulses in the transmit off time of the first transmission cycle and/or the at least one subsequent transmission cycle and prohibiting wireless transmissions for a predetermined time when the number of radar pulses detected is greater than a threshold. ### Claim 8 (depends on 2) The method of claim 2 wherein: extending the transmit off time of the first transmission cycle and/or at least one subsequent transmission cycle comprises extending the transmit off time of a first subsequent transmission cycle by a first duration; and the method further comprises extending a transmit off time of a second subsequent transmission cycle by a second duration greater than the first duration when a number of radar pulses detected in the transmit off time of the first subsequent transmission cycle is lower than a threshold, wherein the second subsequent transmission cycle is subsequent to the first subsequent transmission cycle. ### Claim 9 (depends on 2) The method of claim 2 further comprising repeating the detecting and extending steps until one of the transmit off time is greater than a maximum transmit off time and a number of radar pulses detected is greater than a threshold. ### Claim 10 (depends on 2) The method of claim 2 further comprising repeating the detecting and extending steps for a predetermined number of times. ### Claim 11 (depends on 10) The method of claim 10 wherein the predetermined number of times is dependent on a type of the at least one radar pulse detected. ### Claim 12 (depends on 10) The method of claim 10 further comprising after the predetermined number of times, resetting a transmit off time of a subsequent transmission cycle when a number of the at least one radar pulse detected is lower than a threshold. ### Claim 13 (depends on 10) The method of claim 10 further comprising after the predetermined number of times, incrementally reducing a transmit off time of one or more subsequent transmission cycles when a number of the at least one radar pulse detected is lower than a threshold until the transmit off time reaches a reset value. ### Claim 14 (depends on 2) The method of claim 2 wherein detecting the at least one radar pulse comprises detecting the at least one radar pulse in a channel of the frequency band overlapping with a channel used for the wireless transmission. ### Claim 15 (depends on 2) The method of claim 2 wherein the detecting and extending is performed for at least one secondary cell in which a channel used for wireless transmissions in the frequency band overlaps with a channel used for radar transmissions. ### Claim 16 (depends on 15) The method of claim 15 wherein detecting at least one radar pulse in the frequency band comprises detecting the at least one radar pulse in one of the at least one secondary cell, the method further comprising prohibiting wireless transmissions for a predetermined time in each of the at least one secondary cell when the at least one radar pulse detected is greater than a threshold. ### Claim 17 (depends on 15) The method of claim 15 wherein extending the transmit off time comprises extending the transmit off time in each of the at least one secondary cell such that the transmit on times in the at least one secondary cell do not overlap. ### Claim 18 (depends on 15) The method of claim 15 further comprising sending a message to one or more wireless devices, the message being indicative of the at least one radar pulse detected. ### Claim 19 (depends on 15) The method of claim 15 further comprising sending a message to one or more wireless devices, the message being indicative of a request to stop transmitting. ### Claim 20 (depends on 18) The method of claim 18 wherein the message is sent in one of a broadcast channel, a control channel, and a traffic channel. ### Claim 21 (depends on 18) The method of claim 18 wherein the message is sent in one of a Master Information Block, MIB, a System Information Block, SIB, and a reference signal. ### Claim 22 A network node configured to control wireless transmissions between the network node and wireless devices in a wireless network using a transmission cycle pattern defined by a transmit on time and a transmit off time, the wireless transmissions occurring in a frequency band used for transmissions of higher priority repetitive signals or pulses, the network node comprising circuitry containing instructions which, when executed, cause the network node to: after a wireless transmission during a transmit on time of a first transmission cycle, detect, during a transmit off time of the first transmission cycle, at least one higher priority repetitive signal or pulse in the frequency band; and extend the transmit off time of the first transmission cycle and/or at least one subsequent transmission cycle based on the at least one higher priority repetitive signal or pulse detected. ### Claim 23 (depends on 22) The network node of claim 22 wherein the at least one higher priority repetitive signal or pulse detected in the frequency band is at least one radar pulse detected in the frequency band such that the instructions are configured to cause the network node to detect, during the transmit off time of the first transmission cycle, the at least one radar pulse in the frequency band. ### Claim 24 (depends on 23) The network node of claim 23 wherein the instructions are configured to cause the network node to extend the transmit off time of the first transmission cycle. ### Claim 25 (depends on 23) The network node of claim 23 wherein the instructions are configured to cause the network node to extend the transmit off time of the at least one subsequent transmission cycle. ### Claim 26 (depends on 23) The network node of claim 23 wherein the instructions are configured to cause the network node to extend the transmit off time of the first transmission cycle and the transmit off time of the at least one subsequent transmission cycle. ### Claim 27 (depends on 23) The network node of claim 23 wherein the instructions are further configured to cause the network node to extend the transmit off time of the first transmission cycle and/or the at least one subsequent transmission cycle by one of reducing the transmit on time of the first transmission cycle and/or the at least one subsequent transmission cycle, reducing a duty cycle of the first transmission cycle and/or the at least one subsequent transmission cycle, and extending a transmission cycle period for the first transmission cycle and/or the at least one subsequent transmission cycle. ### Claim 28 (depends on 23) The network node of claim 23 wherein the instructions are further configured to cause the network node to detect a number of radar pulses in the transmit off time of the first transmission cycle and/or the at least one subsequent transmission cycle and prohibit wireless transmissions for a predetermined time when the number of radar pulses detected is greater than a threshold. ### Claim 29 (depends on 23) The network node of claim 23 wherein: the instructions are configured to cause the network node to extend the transmit off time of a first subsequent transmission cycle by a first duration; and the instructions are further configured to cause the network node to extended a transmit off time of a second subsequent transmission cycle by a second duration greater than the first duration when a number of radar pulses detected in the transmit off time of the first subsequent transmission cycle is lower than a threshold, wherein the second subsequent transmission cycle is subsequent to the first subsequent transmission cycle. ### Claim 30 (depends on 23) The network node of claim 23 wherein the instructions are further configured to cause the network node to repeat the detecting and extending until one of the transmit off time is greater than a maximum transmit off time and a number of radar pulses detected is greater than a threshold. ### Claim 31 (depends on 23) The network node of claim 23 wherein the instructions are further configured to cause the network node to repeat the detecting and extending for a predetermined number of times. ### Claim 32 (depends on 31) The network node of claim 31 wherein the predetermined number of times is dependent on a type of the at least one radar pulse detected. ### Claim 33 (depends on 31) The network node of claim 31 wherein the instructions are further configured to cause the network node to after the predetermined number of times, reset a transmit off time of a subsequent transmission cycle when a number of the at least one radar pulse detected is lower than a threshold. ### Claim 34 (depends on 31) The network node of claim 31 wherein the instructions are further configured to cause the network node to, after the predetermined number of times, incrementally reduce a transmit off time of one or more subsequent transmission cycles when a number of the at least one radar pulse detected is lower than a threshold until the transmit off time reaches a reset value. ### Claim 35 (depends on 23) The network node of claim 23 wherein to detect the at least one radar pulse, the instructions are further configured to cause the network node to detect the at least one radar pulse in a channel of the frequency band overlapping with a channel used for the wireless transmission. ### Claim 36 (depends on 23) The network node of claim 23 wherein the instructions are further configured to cause the network node to detect and extend for at least one secondary cell in which a channel used for wireless transmissions in the frequency band overlaps with a channel used for radar transmissions. ### Claim 37 (depends on 36) The network node of claim 36 wherein to detect at least one radar pulse in the frequency band, the instructions are further configured to cause the network node to detect the at least one radar pulse in one of the at least one secondary cell, and to prohibit wireless transmissions for a predetermined time in each of the at least one secondary cell when the at least one radar pulse detected is greater than a threshold. ### Claim 38 (depends on 36) The network node of claim 36 wherein to extend the transmit off time, the instructions are further configured to cause the network node to extend the transmit off time in each of the at least one secondary cell such that the transmit on times in the at least one secondary cell do not overlap. ### Claim 39 (depends on 23) The network node of claim 23 wherein the instructions are further configured to cause the network node to send a message to one or more wireless devices, the message being indicative of the at least one radar pulse detected. ### Claim 40 (depends on 23) The network node of claim 23 wherein the instructions are further configured to cause the network node to send a message to one or more wireless devices, the message being indicative of a request to stop transmitting. ### Claim 41 (depends on 39) The network node of claim 39 wherein the message is sent in one of a broadcast channel, a control channel, and a traffic channel. ### Claim 42 (depends on 39) The network node of claim 39 wherein the message is sent in one of a Master Information Block, MIB, a System Information Block, SIB, and a reference signal. ### Claim 43 A non-transitory computer readable memory configured to store executable instructions for a network node configured to control wireless transmissions between the network node and wireless devices in a wireless network using a transmission cycle pattern defined by a transmit on time and a transmit off time, the wireless transmissions occurring in a frequency band used for transmissions of higher priority repetitive signals or pulses, the executable instructions when executed by a processor cause the network node to: after a wireless transmission during a transmit on time of a first transmission cycle, detect, during a transmit off time of the first transmission cycle, at least one higher priority repetitive signal or pulse in the frequency band; and extend the transmit off time of the first transmission cycle and/or at least one subsequent transmission cycle based on the at least one higher priority repetitive signal or pulse detected.