# US 2021/0243573 A1 · Call prompt method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243573 A1 - Document ID: US20210243573A1 - Status: Published application - Kind: A1 - Application number: 17/237,161 - Filed: 2021-04-22 - Published: 2021-08-05 - Earliest claimed: 2018-06-29 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Hui JIN; Xiaoguang WU; Kaiyu JIANG; Liwen TAN - Web page: https://patentgrep.com/patent/US20210243573A1 ## CPC - H04W 4/16: Communication-related supplementary services, e.g. call-transfer or call-hold - H04M 1/724: User interfaces specially adapted for cordless or mobile telephones - H04M 3/4288: {Notifying a called subscriber of an incoming call during an ongoing call, e.g. Call Waiting} - H04M 1/72513: On hold, intercom or transfer communication modes - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) ## Abstract This disclosure relates to a call prompt method and terminal. In one aspect, the method includes displaying a first interface on a display screen of a first terminal, showing that a first terminal is in a call with a second terminal via the CDMA communication network; while the first terminal is in the call with the second terminal, displaying a second interface on the display screen that prompts that a third terminal is initiating a call to the first terminal; outputting a sound that includes a prompt tone and a call voice between the first terminal and the second terminal, the prompt tone is used to prompt a call event indicating that the third terminal is initiating a call to the first terminal; and when the call initiated by the third terminal is rejected by the first terminal's user, continuing output of the call voice between the first terminal and the second terminal, and stopping output of the prompt tone. ## Claims ### Claim 1 A call prompt method in a Code Division Multiple Access (CDMA) communication network, comprising: displaying a first interface on a display screen of a first terminal, wherein the first interface shows that a first terminal is in a call with a second terminal via the CDMA communication network; while the first terminal is in the call with the second terminal, displaying a second interface on the display screen of the first terminal, wherein the second interface prompts that a third terminal is initiating a call to the first terminal via the CDMA communication network; outputting, on the first terminal, a sound, wherein the sound comprises a prompt tone and a call voice between the first terminal and the second terminal, the prompt tone is used to prompt a call event, and the call event indicates that the third terminal is initiating a call to the first terminal via the CDMA communication network; in response to the call initiated by the third terminal to the first terminal being rejected by a user of the first terminal, continuing output, on the first terminal, of the call voice between the first terminal and the second terminal, and stopping output of the prompt tone to stop prompting the call event. ### Claim 2 (depends on 1) The method according to claim 1, wherein stopping output of the prompt tone comprises changing an amplitude value of a frequency corresponding to the prompt tone. ### Claim 3 (depends on 2) The method according to claim 2, further comprising detecting, by the first terminal, the prompt tone by using a linear spectrum detection method. ### Claim 4 (depends on 3) The method according to claim 3, wherein a fundamental frequency of the prompt tone is a single-frequency tone that has a constant amplitude and a constant frequency; and detecting, by the first terminal, the prompt tone by using the linear spectrum detection method comprises: performing, by the first terminal, channel decoding and voice decoding on a received downlink signal to obtain pulse code modulation (PCM) data; dividing the PCM data into multiple overlapping data frames; multiplying each of the multiple data frames by a window function, and performing a Fourier transformation to obtain a complex spectrum; calculating, at each pre-estimated frequency, a correlation coefficient between complex spectra of a previous frame and a current frame in a relaxation period; and determining, by the first terminal, that the prompt tone is detected on a corresponding frequency in response to the correlation coefficient exceeding a preset threshold. ### Claim 5 (depends on 4) The method according to claim 4, further comprising: after the first terminal receives the call initiated by the third terminal, obtaining, according to network information obtained by the first terminal by parsing a system broadcast message of a current cell, prompt tone information pre-stored in the first terminal, and detecting a prompt tone in the downlink signal according to the pre-stored prompt tone information; and after determining, by the first terminal, that the prompt tone is detected on the corresponding frequency: comparing a frequency and an amplitude of the detected prompt tone with a frequency and an amplitude in the prompt tone information pre-stored in the first terminal; and in response to either determining that the frequency and the amplitude of the detected prompt tone are the same as the frequency and the amplitude in the prompt tone information pre-stored in the first terminal, or determining that differences between the frequency and the amplitude of the detected prompt tone and the frequency and the amplitude in the prompt tone information pre-stored in the first terminal do not exceed comparison thresholds, determining, by the mobile terminal, that the prompt tone is detected. ### Claim 6 A first terminal used in a Code Division Multiple Access (CDMA) communication network, comprising at least one processor, a transceiver, one or more memories, a display screen, an audio frequency circuit, and a bus; wherein: the transceiver is configured to communicate with the CDMA communication network; the display screen is configured to display the first interface and the second interface; and the audio frequency circuit is configured to output a sound, wherein the sound comprises a call voice between the terminal and a second terminal, a prompt tone, or a prompt tone and a call voice between the terminal and a second terminal, the one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one a processor to perform operations comprising: displaying a first interface on a display screen, wherein the first interface shows that a first terminal is in a call with a second terminal via a CDMA communication network; while the first terminal is in the call with the second terminal, displaying a second interface on the display screen, wherein the second interface prompts that a third terminal is initiating a call to the first terminal via the CDMA communication network; instructing the audio frequency circuit to output a sound, wherein the sound comprises a prompt tone and a call voice between the first terminal and the second terminal, the prompt tone is used to prompt a call event, and the call event indicates that the third terminal is initiating a call to the first terminal via the CDMA communication network; in response to the call initiated by the third terminal to the first terminal being rejected by a user of the first terminal, instructing the audio frequency circuit to continue outputting the call voice between the first terminal and the second terminal, and to stop outputting the prompt tone to stop prompting the call event. ### Claim 7 (depends on 6) The first terminal according to claim 6, further comprising: the audio frequency circuit is configured to stop outputting the prompt tone by changing an amplitude value of a frequency corresponding to the prompt tone. ### Claim 8 (depends on 7) The first terminal according to claim 7, wherein the one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor to perform operations further comprising: detecting the prompt tone by using a linear spectrum detection method. ### Claim 9 (depends on 8) The first terminal according to claim 8, wherein a fundamental frequency of the prompt tone is a single-frequency tone that has a constant amplitude and a constant frequency; and detecting the prompt tone by using the linear spectrum detection method comprises: performing channel decoding and voice decoding on the received downlink signal to obtain pulse code modulation (PCM) data; dividing the PCM data into multiple overlapping data frames; multiplying each of the multiple data frames by a window function, and performing a Fourier transformation to obtain a complex spectrum; calculating, at each pre-estimated frequency, a correlation coefficient between complex spectra of a previous frame and a current frame in a relaxation period; and determining, by the first terminal, that the prompt tone is detected on a corresponding frequency in response to the correlation coefficient exceeding a preset threshold. ### Claim 10 (depends on 9) The first terminal according to claim 9, wherein the n or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor to perform operations further comprising: after the first terminal receives the call initiated by the third terminal, obtaining, according to network information obtained by the first terminal by parsing a system broadcast message of a current cell, prompt tone information pre-stored in the first terminal, and detecting a prompt tone in the downlink signal according to the pre-stored prompt tone information; and after determining, by the first terminal, that the prompt tone is detected on the corresponding frequency: comparing a frequency and an amplitude of the detected prompt tone with a frequency and an amplitude in the prompt tone information pre-stored in the first terminal; and in response to either determining that the frequency and the amplitude of the detected prompt tone are the same as the frequency and the amplitude in the prompt tone information pre-stored in the first terminal, or determining that differences between the frequency and the amplitude of the detected prompt tone and the frequency and the amplitude in the prompt tone information pre-stored in the first terminal do not exceed comparison thresholds, determining, by the mobile terminal, that the prompt tone is detected. ### Claim 11 At least one processor used in a Code Division Multiple Access CDMA communications network in a first terminal, wherein the at least one processor is coupled to one or more memories that store programming instructions and the programming instructions, when executed by the at least one processor, cause the at least one processor to perform the following operations: establishing a call with a second terminal via the CDMA communication network; receiving a message from the CDMA communication network, wherein the message indicates that a third terminal is initiating a call to the first terminal via the CDMA communication network, and at this moment, the first terminal is still in a call with the second terminal while the first terminal is in the call with the second terminal; outputting a sound, wherein the sound comprises a prompt tone and a call voice between the first terminal and the second terminal, the prompt tone is used to prompt a call event, and the call event indicates that the third terminal is initiating a call to the first terminal via the CDMA communication network; in response to the call initiated by the third terminal to the first terminal being rejected by a user of the first terminal, continuing output, on the first terminal, of the call voice between the first terminal and the second terminal, and stopping output of the prompt tone to stop prompting the call event. ### Claim 12 (depends on 11) The at least one processor according to claim 11, wherein the stopping output of the prompt tone comprises changing an amplitude value of a frequency corresponding to the prompt tone. ### Claim 13 (depends on 12) The at least one processor according to claim 12, wherein the programming instructions, when executed by the at least one processor, cause the at least one processor to perform the operation of detecting the prompt tone by using a linear spectrum detection method. ### Claim 14 (depends on 13) The at least one processor according to claim 13, wherein a fundamental frequency of the prompt tone is a single-frequency tone that has a constant amplitude and a constant frequency; and detecting the prompt tone by using the linear spectrum detection method comprises: performing, by the at least one processor, channel decoding and voice decoding on the received downlink signal to obtain pulse code modulation (PCM) data; dividing the PCM data into multiple overlapping data frames; multiplying each of the multiple data frames by a window function, and performing a Fourier transformation to obtain a complex spectrum; calculating, at each pre-estimated frequency, a correlation coefficient between complex spectra of a previous frame and a current frame in a relaxation period; and determining, by the at least one processor, that the prompt tone is detected on a corresponding frequency in response to the correlation coefficient exceeding a preset threshold. ### Claim 15 (depends on 14) The at least one processor according to claim 14, wherein the programming instructions, when executed by the at least one processor, cause the at least one processor to perform the operations further comprising: after the processor receives the call initiated by the third terminal, obtaining, according to network information obtained by the processor by parsing a system broadcast message of a current cell, prompt tone information pre-stored in the first terminal, and detecting a prompt tone in the downlink signal according to the pre-stored prompt tone information; and after determining, by the at least one processor, that the prompt tone is detected on a corresponding frequency: comparing a frequency and an amplitude of the detected prompt tone with a frequency and an amplitude in the prompt tone information pre-stored in the first terminal; and in response to either determining that the frequency and the amplitude of the detected prompt tone are the same as the frequency and the amplitude in the prompt tone information pre-stored in the first terminal, or determining that differences between the frequency and the amplitude of the detected prompt tone and the frequency and the amplitude in the prompt tone information pre-stored in the first terminal do not exceed comparison thresholds, determining, by the mobile terminal, that the prompt tone is detected.