Communication method utilizing frequency offset, device, base station and base station control device

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention.

[0021] Under the existing network architecture, the terminal may drop the call because the carrier-to-interference ratio is too high or too low. The inventor of the present invention has found through a lot of tests and analysis that the reason for the terminal to drop the call is mainly because the terminal The deviation of the reference frequency from the network side is too large. Since the reference frequency of the terminal has a large deviation from the reference frequency of the network side, the terminal fails to receive the downlink signal or the base station fails to receive the uplink signal of the terminal, thereby causing call drop. The phenomenon that the reference frequency of the terminal is too large from the reference frequency of the network side can be called frequency out-of-sync. However, the existing method for adjusting the receiving performance of the network and the terminal is to adjust the transmission power of the network side or the terminal by detecting the receiving quality and the receiving level. This method cannot solve the call drop caused by the out-of-synchronization of the terminal frequency. In the prior art, there is no mechanism for detecting the out-of-synchronization of the terminal frequency, and no mechanism for calibrating the reference frequency of the mobile phone according to the detection of the out-of-synchronization of the terminal frequency.

[0022] An embodiment of the present invention provides a communication method using frequency offset, such as figure 1 As shown, the method can include:

[0023] S101, demodulate an uplink signal sent by a terminal, and obtain a first frequency deviation between a carrier frequency of the uplink signal and a reference frequency on a network side;

[0024] After the network side receives the uplink signal sent by the terminal, it will perform demodulation, and the specific demodulation method is basically the same as that in the prior art, which will not be repeated here. When demodulating the uplink signal, the network side can obtain the first frequency offset between the carrier frequency of the uplink signal of the terminal and the reference frequency of the network side through the frequency offset estimation algorithm.

[0025] S102: Determine whether the first frequency deviation satisfies a preset out-of-synchronization condition, and if the first frequency deviation satisfies the preset out-of-synchronization condition, confirm that a frequency out-of-synchronization occurs in the terminal.

[0026] In the prior art, because the phenomenon of frequency desynchronization of the terminal is not considered, after estimating the frequency deviation, only the deviation correction process is performed on the received signal, and it is not detected whether the terminal has a frequency according to the first frequency deviation. out of step. In this embodiment, after estimating the first frequency deviation between the carrier frequency of the uplink signal of the terminal and the reference frequency on the network side in S101, it can be further judged whether the terminal is out of frequency according to the first frequency deviation.

[0027] Wherein, the preset out-of-step condition here may include: the absolute value of the first frequency deviation is greater than or equal to a preset threshold; and/or, the variation characteristic of the first frequency deviation satisfies the preset variation characteristic; and/or , if the base station is located in an area where the terminal is not moving at high speed, the first frequency deviation exceeds the allowable error range; if the base station is located in an area where the terminal is moving at high speed, the absolute value of the first frequency deviation is greater than or equal to the preset threshold.

[0028] There are various ways to judge whether the first frequency deviation satisfies the preset out-of-step condition, for example:

[0029] A. Compare the absolute value of the first frequency deviation with a preset threshold, if the absolute value of the first frequency deviation is greater than or equal to the preset threshold, it can be considered that the terminal satisfies the preset out-of-step condition, and The preset threshold can be set based on experience. In general, if the first frequency deviation caused by the movement of the terminal is not too high, for example, below 400 Hz, then 400 Hz can be used as the preset threshold. Of course, according to Different terminal types or different network systems or different precision requirements, the preset threshold may be different values, which are not listed here. In addition, in order to make the detection result more stable, the obtained absolute values ​​of the plurality of first frequency deviations may be averaged or filtered within the first preset period, and the averaged or filtered result is compared with a preset threshold value.

[0030] B. Compare the change characteristic of the first frequency deviation with the pre-stored change characteristic information, and judge whether the first frequency deviation satisfies the preset out-of-step condition according to the comparison result.

[0031] The pre-stored change characteristic information may be information representing the frequency offset change characteristic caused by the terminal moving, or may be information representing the frequency offset change characteristic caused by the frequency desynchronization of the terminal. The pre-stored change characteristic information can be obtained through pre-test analysis, and is stored on the network side as reference information.

[0032] Specifically, it can be achieved in the following manner: in the second preset period, record the change characteristics of the first frequency deviation, and the recording method can be directly recording the first frequency deviation result obtained by each frequency deviation estimation, or it can be a record book The difference between the carrier frequency of the uplink signal of the secondary terminal and the first frequency deviation of the reference frequency of the network side and the first frequency deviation of the carrier frequency of the uplink signal of the terminal and the reference frequency of the network side last time, this embodiment does not It is limited as long as the variation characteristics of the first frequency deviation can be reflected. The recorded change characteristic of the first frequency deviation can be compared with the pre-stored change characteristic information. For example, the recorded change characteristic of the first frequency deviation can be correlated with the pre-stored change characteristic information to obtain a correlation coefficient. The correlation coefficient determines whether the first frequency deviation satisfies a preset out-of-step condition. If the pre-stored change characteristic information is information representing the frequency offset change characteristic caused by the frequency desynchronization of the terminal, it can be detected whether the correlation coefficient is greater than or equal to a preset first correlation threshold, and if it is greater, it can be considered that the first frequency The deviation satisfies the preset out-of-synchronization condition (that is, it satisfies the preset change characteristic), otherwise, it is considered that the first frequency deviation does not meet the preset out-of-synchronization condition; if the pre-saved change characteristic information is caused by the movement of the terminal The information of the frequency deviation change characteristic, it can be detected whether the correlation coefficient is less than or equal to the preset second correlation threshold, if it is less than, it can be considered that the first frequency deviation satisfies the preset out-of-step condition (that is, it satisfies the preset change characteristic ), otherwise, it is considered that the first frequency deviation does not meet the preset out-of-step condition. Wherein, the first correlation threshold and the second correlation threshold here are any values ​​between 0 and 1, which can be set in actual situations. The second preset period here and the above-mentioned first preset period may be equal or unequal, and the first preset period and the second preset period may be set according to actual needs.

[0033] C. Whether the first frequency deviation satisfies the preset out-of-synchronization condition can be determined in combination with the location information of the base station. If it is known from the location information of the base station that the base station is not deployed in the area where the terminal moves at high speed such as highway or high-speed railway (that is, the terminal is not moving at high speed), and the first frequency deviation is not within the allowable error range (for example, [- 10Hz, 10Hz]), it can be considered that the first frequency deviation satisfies the preset out-of-step condition. If the base station is located in an area where the terminal moves at high speed, it is judged whether the absolute value of the first frequency deviation is greater than the preset threshold, and if it is greater than the preset threshold, it is judged that the first frequency deviation satisfies the preset out-of-sync condition. The preset threshold here and the preset threshold in Mode A may be the same value.

[0034] It should be noted that since there may be a certain error in the frequency offset estimation, an allowable error range may be set here, and the allowable error range may be an open interval, a closed interval, and so on.

[0035]It should be noted that, the above several methods for judging whether the first frequency deviation satisfies the preset out-of-synchronization condition may be used alone or in combination. For example, after judging that the first frequency deviation satisfies the preset out-of-synchronization condition according to the A method, the change characteristics of the first frequency deviation and the pre-stored changes within the second preset period after the judgment according to the B method can be made. Correlation of characteristic information, if the preset out-of-synchronization condition is still met, it is considered that the first frequency deviation satisfies the preset out-of-synchronization condition, which can make the judgment of whether the terminal frequency out-of-synchronization occurs more stable. .

[0036] Through the method in the above embodiment, the phenomenon of terminal frequency out-of-synchronization can be detected, which makes up for the lack of a mechanism for detecting terminal frequency out-of-synchronization in the prior art, so that the reasons for the degradation of voice quality or terminal call drop can be analyzed.

[0037] It should be noted that, the above method can be completed by the base station or the base station control device.

[0038] Further, when it is confirmed that the terminal has a frequency desynchronization phenomenon, the reference frequency of the terminal can be adjusted so that the reference frequency of the terminal can be synchronized with the reference frequency of the network side. Another embodiment of the present invention provides a method using frequency offset. communication methods such as figure 2 As shown, the method can include:

[0039] S201, demodulate the uplink signal sent by the terminal, and obtain a first frequency deviation between the carrier frequency of the uplink signal of the terminal and the reference frequency on the network side;

[0040] S202, determining whether the first frequency deviation satisfies a preset out-of-synchronization condition, and if the first frequency deviation satisfies the preset out-of-synchronization condition, confirming that the terminal has frequency out-of-synchronization;

[0041] For the above processing manners of S201-S202, reference may be made to the relevant descriptions of S101-S102, which will not be repeated here. After S202 detects that the terminal is out of frequency synchronization, execute S203.

[0042] S203, adjust the carrier-to-interference ratio of the downlink signal.

[0043] The adjustment of the carrier-to-interference ratio can be controlled by the base station control device or the base station.

[0044] The reason for the frequency desynchronization may be that the carrier-to-interference ratio is too low, or it may be that the carrier-to-interference ratio is too high. Therefore, adjusting the carrier-to-interference ratio of the downlink signal can either increase the carrier-to-interference ratio or reduce the carrier-to-interference ratio. When determining whether to increase or decrease the carrier-to-interference ratio, you can try, for example, gradually increase the carrier-to-interference ratio first, monitor whether the frequency out-of-sync phenomenon of the terminal disappears within a period of time, or judge whether the carrier-to-interference ratio increases to a certain value (for example, 0dB). ), does the frequency desynchronization of the terminal disappear? If the frequency desynchronization of the terminal does not disappear within a period of time or when the carrier-to-interference ratio increases to a certain value, it may mean that the direction of adjusting the carrier-to-interference ratio is wrong, then Adjust the load-to-dry ratio in the opposite direction. It should be noted that in most cases, the frequency is out of step due to the low CIR. Therefore, when trying to adjust the CIR, you can first try to increase the CIR.

[0045] Among them, the way to improve the carrier-to-interference ratio of the downlink signal can be:

[0046] Increase the power of the signal sent to the terminal; or reduce the power of the signal that interferes with the terminal; or switch the terminal to another channel with a better carrier-to-interference ratio (that is, the carrier-to-interference ratio is higher than that of the channel where the terminal is currently located). than the channel). The above methods can be used alone or in combination. It should be noted that the signal causing interference to the terminal may be the signal of other terminals in the cell or the signal of the terminal of the adjacent cell. In addition, for the VAMOS technology scenario, the signal that the terminal generates interference is mainly other terminals that multiplex the same channel; and the other channel with better interference is generally other independent non-multiplexed channels.

[0047] Among them, the way to reduce the carrier-to-interference ratio of the downlink signal can be:

[0048] Reduce the power of the signal sent to the terminal; or increase the power of the signal that interferes with the terminal; or switch the terminal to another channel with a lower carrier-to-interference ratio (that is, the carrier-to-interference ratio is lower than the carrier-to-interference ratio of the channel where the terminal is currently located). than the channel). In addition, for the VAMOS technology scenario, the signal that the terminal generates interference is mainly other terminals multiplexing the same channel.

[0049] S204: Acquire a second frequency deviation between the current carrier frequency of the uplink signal of the terminal and the reference frequency on the network side, and confirm whether the frequency out-of-sync of the terminal is eliminated according to the second frequency deviation and a preset synchronization condition.

[0050] The network side can continue to monitor the second frequency deviation between the carrier frequency of the uplink signal of the terminal and the reference frequency of the network side after adjusting the carrier-to-interference ratio, and judge whether the frequency out-of-sync of the terminal is eliminated according to the second frequency deviation and the preset synchronization condition. , if the second frequency deviation satisfies the preset synchronization condition, it is confirmed that the frequency desynchronization of the terminal is eliminated.

[0051] Wherein, the preset synchronization conditions may include:

[0052] The absolute value of the second frequency deviation is smaller than the preset threshold (it should be noted that, for the case where the absolute value of the second frequency deviation is equal to the preset threshold, it may also be considered that the synchronization condition is satisfied); and/or,

[0053] When the pre-stored change characteristic information is information representing the frequency offset change characteristic caused by the terminal frequency desynchronization, the correlation coefficient between the change characteristic of the second frequency deviation and the pre-stored change characteristic information is smaller than the preset first correlation threshold (required It should be noted that, for the case where the second frequency deviation is equal to the first correlation threshold, it can also be considered that the synchronization condition is satisfied); when the pre-stored change characteristic information is information representing the frequency deviation change characteristic caused by the terminal movement, the second frequency The correlation coefficient between the variation characteristic of the deviation and the pre-stored variation characteristic information is greater than the preset second correlation threshold (it should be noted that, for the situation that the second frequency deviation is equal to the second correlation threshold, it can also be considered that the synchronization condition is satisfied); and / or,

[0054] If the base station is located in an area where the terminal is not moving at a high speed, the second frequency deviation is within the allowable error range; if the base station is located in an area where the terminal is moving at a high speed, the absolute value of the second frequency deviation is less than the preset threshold (it should be noted that, For the case where the absolute value of the second frequency deviation is equal to the preset threshold, it may also be considered that the synchronization condition is satisfied).

[0055] If it is determined that the frequency desynchronization of the terminal is not eliminated, the carrier-to-interference ratio can be further adjusted and it is determined whether the frequency desynchronization is eliminated until the frequency desynchronization of the terminal is eliminated.

[0056] In the method of this embodiment, after confirming that the terminal frequency is out of sync, the reference frequency of the terminal is adjusted by adjusting the carrier-to-interference ratio of the downlink signal, so as to avoid the degradation of the voice quality or the call drop of the terminal as much as possible.

[0057] An embodiment of the present invention also provides a communication device using frequency offset, such as image 3 As shown, the apparatus may include:

[0058] a frequency deviation obtaining module 301, configured to demodulate the uplink signal sent by the terminal, and obtain the first frequency deviation between the carrier frequency of the uplink signal and the reference frequency on the network side;

[0059] After the network side receives the uplink signal sent by the terminal, it will perform demodulation, and the specific demodulation method is basically the same as that in the prior art, which will not be repeated here. When demodulating the uplink signal, the network side can obtain the first frequency offset between the carrier frequency of the uplink signal of the terminal and the reference frequency of the network side through the frequency offset estimation algorithm.

[0060] The confirmation module 302 is used for judging whether the first frequency deviation obtained by the frequency deviation obtaining module 301 satisfies the preset out-of-synchronization condition, and if the first frequency deviation satisfies the preset out-of-synchronization condition, confirming that the terminal has frequency out-of-synchronization.

[0061] Wherein, the preset out-of-synchronization condition here may include: the absolute value of the first frequency deviation is greater than the preset threshold; and/or, the variation characteristic of the first frequency deviation satisfies the preset variation characteristic; and/or, if The base station is located in an area where the terminal is not moving at a high speed, and the first frequency deviation exceeds the allowable error range. If the base station is located in an area where the terminal is moving at a high speed, the absolute value of the first frequency deviation is greater than a preset threshold.

[0062] For the manner of judging whether the acquired first frequency deviation satisfies the preset out-of-synchronization condition, reference may be made to the relevant descriptions in the foregoing method embodiments, which will not be repeated here.

[0063] The device in the above embodiment determines whether the terminal frequency is out of synchronization by detecting the relationship between the frequency deviation and the preset out-of-synchronization condition, which makes up for the blank that there is no mechanism for detecting the terminal frequency out-of-synchronization in the prior art. Analyze the reasons that make the voice quality degrade or the terminal dropped calls.

[0064] Further, when it is confirmed that the terminal has a frequency desynchronization phenomenon, the reference frequency of the terminal can be adjusted so that the reference frequency of the terminal can be synchronized with the reference frequency of the network side. Another embodiment of the present invention provides a method using frequency offset. communication devices such as Figure 4 As shown, the apparatus may include:

[0065] A frequency deviation obtaining module 401, configured to demodulate the uplink signal sent by the terminal, and obtain the first frequency deviation between the carrier frequency of the uplink signal and the reference frequency on the network side;

[0066] A confirmation module 402, configured to judge whether the first frequency deviation obtained by the frequency deviation obtaining module 401 satisfies a preset out-of-synchronization condition, and if the first frequency deviation satisfies the preset out-of-synchronization condition, confirm that the terminal has frequency out-of-synchronization;

[0067] The processing method and functional structure of the above frequency deviation acquisition module 401 and confirmation module 402 are the same as image 3 The frequency deviation acquisition module 301 and the confirmation module 302 in the illustrated embodiment are basically the same, and are not repeated here.

[0068] The adjustment module 403 is configured to adjust the carrier-to-interference ratio of the downlink signal after the confirmation module 402 confirms that the terminal is out of frequency;

[0069] Wherein, adjusting the carrier-to-interference ratio of the downlink signal may include: increasing or decreasing the carrier-to-interference ratio of the downlink signal.

[0070] There are many ways to improve the carrier-to-interference ratio of the downlink signal: increase the power of the downlink signal sent to the terminal; or reduce the power of the downlink signal that interferes with the terminal; or switch the terminal to a higher carrier-to-interference ratio than the terminal is currently in. The channel's carrier-to-interference ratio of the channel;

[0071] There are also many ways to reduce the carrier-to-interference ratio of the downlink signal: reduce the power of the downlink signal sent to the terminal; or increase the power of the downlink signal that interferes with the terminal; or switch the terminal to a channel with a lower carrier-to-interference than the terminal is currently on. the carrier-to-interference ratio of the channel. For details, please refer to figure 2 Relevant descriptions in the illustrated embodiments are not repeated here.

[0072] The network side can continue to monitor the first frequency deviation between the carrier frequency of the uplink signal of the terminal and the reference frequency of the network side after adjusting the carrier-to-interference ratio, then the communication device using the frequency deviation in this embodiment may further include: a judging module 404;

[0073] The frequency deviation acquisition module 401, after the adjustment module 403 adjusts the carrier-to-interference ratio of the downlink signal, acquires the second frequency deviation between the carrier frequency of the currently received uplink signal and the reference frequency on the network side;

[0074] The judgment module 404 is used to confirm whether the frequency out-of-synchronization of the terminal is eliminated according to the second frequency deviation and the preset synchronization condition, and if the second frequency deviation meets the preset synchronization condition, then confirm that the frequency out-of-synchronization of the terminal is eliminated .

[0075] However, if the second frequency deviation does not meet the preset synchronization condition, the adjustment module 403 may continue to adjust the carrier-to-interference ratio of the downlink signal. Preset synchronization conditions can include:

[0076] The absolute value of the second frequency deviation is less than or equal to the preset threshold; and/or,

[0077] When the pre-stored change characteristic information is information representing the frequency offset change characteristic caused by the terminal frequency desynchronization, the correlation coefficient between the change characteristic of the second frequency deviation and the pre-stored change characteristic information is less than the preset first correlation threshold; when When the pre-stored change characteristic information is information representing the frequency offset change characteristic caused by the movement of the terminal, the correlation coefficient between the change characteristic of the second frequency deviation and the pre-stored change characteristic information is greater than the preset second correlation threshold; and/or,

[0078] If the base station is located in an area where the terminal is not moving at a high speed, the second frequency deviation is within the allowable error range; if the base station is located in an area where the terminal is moving at a high speed, the absolute value of the second frequency deviation is less than or equal to the preset threshold.

[0079] It should be noted that, for the processing, interaction process, and specific structural functions of the above modules, reference may be made to the relevant descriptions in the method embodiments, which will not be repeated here.

[0080] The apparatus of this embodiment adjusts the reference frequency of the terminal by adjusting the carrier-to-interference ratio of the downlink signal after confirming that the frequency of the terminal is out of synchronization, so as to avoid the degradation of the voice quality or the call drop of the terminal as much as possible.

[0081] An embodiment of the present invention further provides a base station, including image 3 or Figure 4 The communication device utilizing frequency offset according to the illustrated embodiment.

[0082] Another embodiment of the present invention also provides a base station control device, comprising: image 3 or Figure 4 The communication device utilizing frequency offset according to the illustrated embodiment.

[0083] The technical solution of this embodiment can be applied to various communication systems, such as: GSM, Code Division Multiple Access (CDMA, Code Division Multiple Access) system, Wideband Code Division Multiple Access (WCDMA, Wideband Code Division Multiple Access Wireless), time division Synchronous Code Division Multiple Access (TimeDivision Synchronous Code Division Multiple Access, TD-SCDMA), Long Term Evolution (LTE, Long Term Evolution), etc. It can be applied to any system where the terminal frequency may be out of sync. In the GSM system, the terminal is a mobile station (Mobile Station, MS), the base station is a base transceiver station (Base Transceiver Station, BTS), and the base station control device is a base station controller (Base Station Controller, BSC); in WCDMA and TD- In the SCDMA system, the terminal is a user equipment (User Equipment, UE), the base station is a NodeB, and the base station control device is a radio network controller (Radio Network Controller, RNC). ), the base station control equipment is a serving gateway (Servicing Gateway, SGW) and a mobile management entity (Mobile Management Entity, MME).

[0084] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

[0085] Those of ordinary skill in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium. The medium can be read-only memory, magnetic disk or optical disk, etc.

[0086] The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.