TW201001942A - Mobile terminal device and roaming method thereof - Google Patents

Abstract

A mobile terminal device includes a detecting module, a roaming adjusting module, a site detecting module, a roaming deciding module, and a roaming execute module. The detecting module is used for detecting communication environment parameters of a plurality of access points, and a roaming frequency parameter and a packet retransmission rate of the mobile terminal device. The roaming policy module is used for calculating a radio quality index (RQI) via the communication environment parameters of the access points, and the roaming frequency parameter and the packet retransmission rate of the mobile terminal device. The site detecting module is used for calculating a user movement index (UMI) according to the RQI, and adjusting frequency of the mobile terminal device for scanning object access points according to the UMI. The roaming deciding module is used for receiving the UMI, and determining whether an object access point is content with a roaming condition corresponding to the UMI. The roaming execute module is used for receiving roaming execute command from the roaming deciding module, and cutting off the communication between the mobile terminal device and the current access point and connecting the mobile terminal device communications with the object access point.

Description

201001942 IX. Description of the Invention: [Technical Field] The present invention relates to a mobile terminal device, and more particularly to a mobile terminal device that roams using communication environment parameters of a plurality of base stations and a roaming method thereof. [Prior Art] With the universal application of the base station, the mobile terminal device can realize the uplink by establishing a connection with the wireless local area network base station (Access Point, AP). Generally, each base station can be connected to a certain number of wireless terminal devices. When the base station's Receive Signal Strength Indication (RSSI) is weakened or the current network congestion becomes serious, the base station is caused. The connection to the mobile terminal device is interrupted, thereby interrupting the data transfer. In order to prevent data transmission interruption due to connection interruption, the mobile terminal equipment usually roams from the current base station to a target base station that is better than the current base station. In the prior art, the mobile terminal device generally selects a base station whose RSSI is stronger than the current base station and whose network quality is better than the current network as the target of roaming, and the mobile terminal device continuously scans the target base at a fixed frequency during the roaming process. Taiwan selects a better base station as the target of roaming, but continuously scanning at a fixed frequency will cause rapid consumption of power of the mobile terminal equipment. SUMMARY OF THE INVENTION In view of the above, the present invention provides a mobile terminal device and a roaming method thereof that can save power consumption. A mobile terminal device for roaming from a current base station to a target base station according to a communication environment 201001942 of a plurality of base stations, the mobile terminal device comprising: a detection module, configured to detect a current of the plurality of base stations within a predetermined detection time a communication environment parameter and a roaming frequency of the mobile terminal device and a packet transmission failure rate; a roaming adjustment module, configured to receive a current communication environment parameter of the plurality of base stations, a roaming frequency of the mobile terminal device, and a packet transmission failure rate, and calculate Obtaining a Radio Quality Index (RQI) value, and adjusting a roaming threshold of the current base station according to the RQI value; and a position detecting module, configured to receive an RQI value of the roaming adjustment module, and calculate a user movement index (UMI) value, and adjusting a frequency of the mobile terminal device scanning the target base station according to the UMI value; and a roaming determining module, configured to receive the current status of the base stations sent by the detecting module Communication environment parameters and the roaming frequency of the mobile terminal device and the packet transmission failure rate are connected The UMI value sent by the location detecting module, 'and determining whether there is a target base station that satisfies the roaming condition corresponding to the UMI value; and the roaming execution module, when the roaming determining module determines that the UMI is satisfied Receiving the roaming execution command sent by the roaming decision module and the Received Signal Strength Indication (RSSI) value of the target base station, and disconnecting the mobile terminal device from the target base station of the roaming condition corresponding to the value The communication of the current base station and establishing communication between the mobile terminal device and the target base station. 9 201001942 A roaming method applied to the mobile terminal device, comprising the following steps: the detecting module detects a current communication environment parameter of the base station area and a roaming frequency and a packet sending failure rate of the mobile terminal device in a predetermined detection time; The detection module sends the current communication environment parameter of the base station area, the roaming frequency of the mobile terminal device, and the packet transmission failure rate to the roaming adjustment module and the roaming decision module; the roaming adjustment module passes the calculation base station area The current communication environment parameter is used to obtain a Radio Quality Index (RQI) value, and the roaming threshold of the current base station is adjusted according to the RQI value, and the RQI value is sent to the position detection module; The group receives the RQI value of the roaming adjustment module, and calculates a User Movement Index (UMI) value according to the RQI value, and adjusts, according to the UMI value, a frequency at which the mobile terminal device scans the target base station; the roaming Determining, by the module, whether there is a target base station that satisfies the roaming condition corresponding to the UMI value; If there is a target base station that satisfies the roaming condition, the roaming execution module receives a roaming execution command sent by the roaming decision module to receive a Received Signal Strength Indication (RSI) value of the target base station, and disconnects the mobile station. The terminal device communicates with the base station, and establishes communication between the mobile terminal device and the target base station. If there is no target base station that satisfies the roaming condition corresponding to the UMI value, the operation ends. 201001942 Compared with the prior art, the location detection module adjusts the frequency at which the mobile terminal device scans the target base station according to the UMI value, and the roaming decision module determines whether the target base station meets the roaming condition corresponding to the UMI value. The mobile terminal device can successfully roam to the target base station, and the mobile terminal device automatically adjusts the frequency of scanning the target base station according to the mobile state of the user during the roaming process, and reduces the roaming process of the mobile terminal device by adjusting the scanning frequency. Energy consumption in the middle. [Embodiment] Referring to Figure 1, a preferred embodiment of a mobile terminal device 200 of the present invention is applied to a base station area 100. The base station area 100 includes a plurality of base stations such as base stations 110, 120, 130, .... In the present embodiment, the mobile terminal device 200 and the base stations 110, 120, 130, ... are devices conforming to the WiFi standard of the Institute of Electrical and Electronics Engineers (IEEE) 802.11. The mobile terminal device 200 and the base stations 110, 120, 130, ... may also be devices that comply with other standards. In this embodiment, the mobile terminal device 200 communicates with the base station 110, and when the communication environment in which the base station 110 is located is gradually deteriorated so that the mobile terminal device 200 cannot be kept in the WiFi network all the time, the mobile terminal The terminal device 200 interrupts the communication connection with the base station 110. At this time, the mobile terminal device 200 needs to roam from the base station 110 to another base station such as the base stations 120, 130, ... to maintain the The mobile terminal device 200 is always in the WiFi network. Referring to FIG. 2, the mobile terminal device 200 includes a detection module 11 201001942 group 210, a roaming adjustment module 220, a position detection module 230, a roaming decision module 240, and a roaming execution module 250. The modules in the mobile terminal device 200 can be constructed by computer programs or circuits. The detection module 210 is configured to detect a communication environment condition of an environment in which the mobile terminal device 200 is located within a predetermined detection time, where the communication environment status includes a current communication environment parameter of the base station area 100 and a roaming frequency and a packet of the mobile terminal device 200. Send failure rate. The current communication environment parameter of the base station area 100 includes a quality of service basic service set (QBSS) of the base station area 100 and a received signal strength indication (Received Signal Strength Indication) of the base station area 100. RSSI) Rate of change. The QBSS of the base station area 100 identifies the current utilization rate of each base station channel and the load amount of each base station. The larger the QBSS value, the smaller the utilization rate of each current base station channel, each The greater the load on the base station, the worse the service quality of the base station area 100 is. The RSSI change rate of the base station area 100 is the amount of change of the base station area 100 during the detection time, and identifies the working stability of each base 1' platform. The larger the RSSI value, the better the service quality of each base station. . The roaming frequency of the mobile terminal device 200 is that the detecting module 210 detects the number of times the mobile terminal device 200 roams during the system working time within a predetermined detection time, and the roaming frequency of the mobile terminal device 200 identifies the mobile terminal device 200 and the The base station area 100 has a communication connection stability. The higher the roaming frequency of the mobile terminal device 200, the worse the communication stability between the mobile terminal device 200 and the base station area 100 is. The packet transmission failure rate of the mobile terminal device 200 is the number of times the packet transmission failure is lost during the voice operation time. The number of times the mobile terminal device 200 and its corresponding communication base station (in this embodiment, the base station 110) are connected. The stability 'the higher the packet transmission failure rate of the mobile terminal device 200' is, the worse the communication stability of the mobile terminal device 200 and the base station 110 is. The detection time, system operation time, and voice operation time can be set to the same value or different values according to actual needs. The roaming adjustment module 220 is configured to receive the current communication environment parameter of the base station area and the roaming frequency and the packet transmission failure rate of the mobile terminal device 200, and calculate a radio quality indicator. (Radio Quality Index, RQI) value, and adjusts the roaming threshold (Roaming Threshold) of the base station in communication with the mobile terminal device 200 according to the calculated RQI value. In the present embodiment, the roaming adjustment module 220 obtains an RQI value through an operation formula. The RQI value is calculated as: RQI=Max_RQI-iRQI (1) where RQI maximum is the preset value, and 'iRQI=(((Avg_QBSS + Max—QBSS) * Max_RQI ) * 0.5) + (((Roam_Freq + Max_Freq) * Max_RQI ) * 0.2) + (((Retx_Rate -r Max_Retx_Rate) * Max_RQI ) * 0.2) + (((Avg_RSSI_ Variance + Max_RSSI_ Variance) * Max_RQI ) * 0.1). (2) Among them,

Max_RQI : RQI maximum;

Max QBSS : QBSS maximum; 13 201001942

Avg_QBSS : QBSS average;

Max_Freq: the maximum number of roaming times;

Roam_Freq: the number of current roaming of the mobile terminal device 200; Max_Retx_Rate: the maximum packet transmission failure rate;

Retx_Rate: current packet transmission failure rate of the mobile terminal device 200; Max_RSSI_Variance: the maximum value of the RSSI change rate of the base station area 100;

Avg_RSSI_Variance: The average of the RSSI rate of change for the base station area 100. The value of Max_RQI is preset to 100, the value of Max_QBSS is preset to 100, and Avg_QBSS is the average value of QBSS of all base stations in the base station area 100. Max_Freq is the maximum number of times that the mobile terminal device 200 roams during the system operating time. R〇am_Freq is the detection module 210 detecting the number of times the mobile terminal device 200 actually roams during the system operation time within a predetermined detection time. Max_Retx_Rate is the maximum packet transmission failure rate of the mobile terminal device 200 during the voice job time. The Retx_Rate detects, for the detection module 210, the actual current packet transmission failure rate of the mobile terminal device 200 during the voice working time within a predetermined detection time. Max_RSSI_Variance is the maximum rate of change of the RSSI of the base station area 100 during the detection time. The Avg_RSSI_Variance is an average value of the RSSI change rate of the base station area 100 detected by the detection module 210 within a predetermined detection time. In this embodiment, different RQI values identify different communication environment states, including a normal state, a high traffic state, and a state of interference (also referred to as a severe interference state). The preset values 40 and 70 are preset in the roaming adjustment module 220. If the RQI value is greater than or equal to the preset value of 7〇', the communication environment state of the base station area is normal, and the communication environment quality is Normal; if the RQI value is greater than or equal to the preset value of 40, and is less than the preset value of 70 ', then the communication environment state of the base station area 1 is in a high traffic state, and the communication environment quality is relatively poor; if the RQI value is less than the pre- If the value is 40, the communication environment state of the base station area 100 is in an interference state, and the communication environment quality is even worse. According to the RQI value, more or less communication f environmental quality status can be distinguished, and the threshold values of various communication environment quality states are not limited to the preset values 40 and 70, and different values can be set according to actual needs. In this embodiment, the roaming adjustment module 220 can adjust the roaming threshold of the base station area 100 that is in communication with the mobile terminal device 200 according to the RQ1 value. If the RQI value is less than 70', the roaming adjustment module 220 raises the roaming threshold value of the base station 110 in communication with the mobile terminal device 200. The smaller the RQI value, the more the roaming threshold will be adjusted. The δ halving threshold includes a difference between the target base station after the mobile terminal device 200 roams and the RSSI of the base station 11 that communicates with the mobile terminal device 200 before the I and the difference between the QBSS. The location detecting module 230 is configured to find an alternate target base station for the mobile terminal device 200 when the mobile terminal device 200 communicates with the base station 110. When the mobile terminal device 200 communicates with the base station 110, In order to enable the mobile terminal device 200 to quickly roam to the alternate target base station. The position detection module 230 calculates a user movement index (User Movement Index, 15 201001942: 2: according to the rqj value of the roaming adjustment module 220, and adjusts the frequency of the mobile terminal base station according to the UMI value. In the implementation of the field, the user with different denominations has different grievances, and the user's movement status includes static if the user moves to a static state == pain and running state. Expand the scanning interval to two short sweeps (four) rate, that is, walking state, because If the user moves the port, the user's mobile state is 10°, and the communication signal will not be quickly weakened. The == frequency is between the scanning frequency of the stationary state and the running state. If the user moves to the running state, because the user uses the second The mobile terminal device 200 and the base station area _ weakened or even interrupted. At this time, the mobile terminal sets a 200 rate of demand to use the target base station. Therefore, a higher scanning frequency can be set to enable the mobile terminal device to roam finely and quickly. To the target base station. -: Kind, the scanning frequency of the state is different, and the conventional technology only scans with the rate of the item, so the invention can effectively save Sources for the roaming determining module 240 receives the detection module 210 transmits the

H also i iT Γ 10 0 current communication environment parameters and the mobile terminal device, / and the frequency of the visit, and receive the UMI value sent by the position detection module 230 ~ the travel decision module 240 is used to determine whether the UMi is satisfied The target base station with the value relative to the roaming condition, if there is a target base station that satisfies the corresponding yaw condition of the face, the roaming decision module sends a roaming command to the roaming execution module 25〇 to notify the roaming execution The module 16 201001942 250 establishes a connection with the target base station; if there is no target base station that satisfies the roaming condition corresponding to the UMI value, the operation ends. The roaming execution module 250 is configured to receive the roaming execution command sent by the roaming decision module 240 and the RSSI of the base station area 100, disconnect the mobile terminal device 200 from the base station 110, and establish the mobile terminal device. 200 communication with the target base station. 3 is a preferred embodiment of the mobile terminal device 200 and the base station communication method of FIG. 2, including the following steps: Step S1: The detection module 210 detects the current communication environment parameter of the base station area 100 within a predetermined detection time. And the roaming frequency and packet transmission failure rate of the mobile terminal device 200. Step S2: The detection module 210 sends the current communication environment parameter of the base station area 100 and the roaming frequency and packet transmission failure rate of the mobile terminal device 200 to the roaming adjustment module 220 and the roaming decision module 240. Step S3: The roaming adjustment module 220 obtains an RQI value by calculating a current communication environment of all the base stations, and adjusts a roaming threshold value of the base V station area 100 according to the RQI value, and sends the RQI value to the position detection mode. Group 230. Step S4: The location detection module 230 receives the RQI value of the roaming adjustment module 220 and calculates a user mobility index UMI value according to the RQI value, and adjusts the mobile terminal device 200 to scan the target base station according to the UMI value. frequency. Step S5: The roaming decision module 240 determines whether there is a target base station that satisfies the roaming condition corresponding to the UMI value. 17 201001942 Step S6: If there is a target base station that satisfies the roaming condition corresponding to the UMI, the roaming execution module 25 receives the hard-run execution command sent by the roaming decision module to disconnect the mobile terminal device 200 from The base station communicates with the base station and establishes the communication between the mobile terminal device 200 and the target base station. If the target base station does not satisfy the roaming condition corresponding to the UMI value, the operation ends. The mobile phone terminal 200 has a communication environment of multiple base stations and the communication environment of the plurality of base stations is used. By adjusting the frequency of the mobile terminal device 200 scanning the target base station, the mobile terminal device 200 can successfully roam to Target, ground, δ hai mobile terminal equipment according to the user's movement during the roaming process. At Ρ, the frequency of the target base station is automatically scanned for 5 weeks, and the energy consumption of the mobile terminal device roaming process is reduced by adjusting the scanning rate. According to the above description, the present invention complies with the requirements of the invention patent, and the specific application of the invention is only in accordance with the law. The above is only the specific embodiment of the present invention, and the person skilled in the present invention is in accordance with the present invention. Equivalent modification or degeneration of the spirit shall be covered by the following patent application. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of communication between a preferred embodiment of a mobile terminal device and a base station according to the present invention. ° is a block diagram of a preferred embodiment of a mobile terminal device. 3 is a flow chart of a preferred embodiment of the roaming method of the mobile terminal device of FIG. [Description of main component symbols] Mobile terminal device 200 Base station area 1〇〇18 201001942 Base station 110, 120, 130 detection module 210 Roaming adjustment module 220 Position detection module 230 Roaming decision module 240 Roaming execution module 250 19

Claims (1)

201001942 X. Patent application scope 1. A mobile terminal device for roaming from a current base station to a target base station according to the number of communication environment bundles of the plurality of base stations, the mobile terminal device comprising: a detection module for performing predetermined detection Detecting the current communication environment parameters of the plurality of base stations and the roaming frequency and the transmission failure rate of the mobile terminal device; and the roaming adjustment module, configured to receive the current communication environment parameter of the plurality of base stations and roaming the mobile terminal device Frequency and packet transmission failure rate, and calculating a radio quality indicator value, and adjusting a roaming threshold of the current base station according to the radio quality indicator value; a location system module for receiving the benefit; The line quality indicator value is calculated, and the user movement index value is calculated, and the frequency of the mobile terminal device scanning the target base station is adjusted according to the user: the mobile finger value; the sneak determination module is configured to receive the detection module The bases to be sent, the parameters of the σ田刖通, and the roaming frequency and packet transmission failure of the mobile terminal device , the sub-received location, the group mobile transmission index sent by the group: ==No, there is a target base station that satisfies the roaming condition corresponding to the user's mobile index value; and the ## roaming determination module determines that the movement is satisfied When the target base station of the roaming condition corresponding to the heart value is received, the roaming execution command sent by the roaming (four) group and the connection strength of the target base station are not worth 'disconnecting the mobile terminal device from the current base station' And establishing communication between the mobile terminal device and the target base station. 2. For the mobile terminal equipment as described in the application for the patent Fanyuan project: 20 201001942 The current communication environment parameters of the base station include the service quality values of the basic service units of the base stations and the connection and signal strength of the base stations. Indicating the rate of change 'the service quality value of the basic service unit of the base stations identifies the utilization rate of each base station channel and the load amount of each base station, and the rate of change of the received signal strength indication is the rate of each base station within the detection time The amount of change identifies the operational stability of each base station. 3. The mobile terminal device of claim 1, wherein the mobile terminal device roaming frequency is that the detecting module detects that the mobile terminal device roams during the system operating time of the mobile terminal device within a predetermined detection time. The number of times, the roaming frequency of the mobile terminal device identifies that the communication stability of the mobile terminal device and the current base station is 'the higher the roaming frequency of the mobile terminal device', and the communication stability between the mobile terminal device and the current base station is worse. 4. The mobile terminal device according to claim 1, wherein the packet transmission failure rate of the mobile terminal device is a number of packet transmission failures during the voice operation time, and the current base station identifying the mobile terminal device and its corresponding communication Communication stability. 5. The mobile terminal device according to claim 1, wherein the calculation formula of the radio quality indicator value is: RQI=Max_RQI-iRQI, (1) iRQI=(((Avg_QBSS + Max_QBSS)* Max_RQI) * 0.5) + (((Roam_Freq Max_Freq) * Max_RQI ) * 0.2) + (((Retx_Rate -r Max_Retx_Rate) * Max_RQI ) * 0.2) + (((Avg_RSSI_Variance + Max_RSSI-Variance) * Max_RQI ) * 0.1 ), (2) 21 201001942 where RQI is the radio quality indicator value; QBSS is the service quality value of the basic service unit; RSSI is the received signal strength indicator value; Max_RQI = 100; Max_QBSS = 100; Max_RQI: RQI maximum value; Max_QBSS: QBSS maximum; Avg_QBSS: QBSS average; Max_Freq: maximum roaming limit; Roam_Freq: number of current roaming of mobile terminal devices; Max_Retx_Rate: maximum packet transmission failure rate; Retx_Rate: current packet transmission failure rate of mobile terminal equipment; Max_RSSI_Variance: The maximum RSSI rate of change in the base station area; Avg_RSSI_Variance: The average of the RSSI rate of change in the base station area. 6. The mobile terminal device of claim 5, wherein the different radio quality indicator values identify different communication environment states, and the communication environment state includes a normal state, a high traffic state, and an interference state. 7. The mobile terminal device of claim 6, wherein the roaming adjustment module presets a first preset value and a second preset value, and the first preset value is greater than the second preset Set the value, if the radio quality indicator value is greater than or equal to the first preset value, the communication environment status of the current base station is in positive 22 201001942 hanging shape: 纟通汛% i brother quality is normal; if the radio quality indicator value If the second preset value is greater than or equal to the second preset value, and the communication environment state of the current base station is in a high traffic state, the communication environment quality is compared; if the radio quality indicator value is smaller than the second preset The value is the communication of the current base σ; the state of the clothing is in a state of interference, and the communication environment is often poor. 8. The mobile terminal device as claimed in claim </ RTI> wherein the roaming value includes a value of the received signal strength of the target base station and the Tiangang base port after the mobile terminal device roams The difference between the difference and the service quality of the basic service unit. The L-type roaming method applied to the mobile terminal device according to claim 1 of the patent application scope includes the following steps: _ the detection module detects the predetermined detection time The current communication environment parameters of the base station area and the roaming frequency and packet transmission of the mobile terminal equipment: failure rate, the current communication environment parameter of the base station area and the roaming frequency of the mobile terminal equipment and the packet transmission a failure rate to the roaming adjustment module and the roaming decision module; the roaming adjustment module obtains a radio quality indication value by calculating current communication environment parameters of all base stations, and adjusts roaming of the base station area according to the radio quality indication value a threshold value, and sending the radio quality indicator value to the location detection module; and the location integration module receives the The radio quality indicator value of the adjustment module is calculated according to the radio quality indicator value, and the user mobile index 23 201001942 value is calculated, and the frequency of the base station is marked according to the user movement index value; the mobile terminal device is adjusted to scan the s. The module determines whether there is a target base H that satisfies the roaming condition corresponding to the roaming condition, and the value of the roaming condition that satisfies the user mobile index value is similar to the roaming condition sent by the roaming decision module: the terminal setting value _Mobile end, ^A situation and establish the mobile terminal device to communicate with the target nr 'If there is no target base station that satisfies the roaming condition corresponding to the user's mobile index value, then the operation ends. The roaming method of the item, wherein the current communication environment parameters of the base ports include the basic service units of the base stations, the service quality values, and the rate of change of the received signal strength indications of the base stations, and/or the base σ The service quality value of the basic service unit identifies the utilization rate of each base station channel and the load amount of each base station, and the received signal strength refers to The rate of change is the change of each base station during the detection time [identifying the stability of each base station. 11. The roaming method described in item 9 of the patent scope of the mountain, the mobile y end in the middle) The roaming frequency is that the detecting module detects the number of roaming of the mobile terminal device during the system operating time of the calling terminal device within a predetermined detection time, and the roaming frequency of the mobile terminal device identifies the mobile terminal device/, the field If the communication stability of the base station is the same, the roaming frequency of the mobile terminal device is the same, and the communication stability between the mobile terminal device and the current base station is worse. 12. The roaming method according to claim 9, wherein the mobile terminal 24 201001942 The packet transmission failure rate of the terminal device is the number of times the packet transmission fails during the voice operation time, and identifies the current base station communication stability of the mobile terminal device and its corresponding communication. 13. The roaming method according to claim 9, wherein the radio quality is not worth the formula: RQI = Max_RQI-iRQI, (1) iRQI = (((Avg_QBSS 4-Max_QBSS) * Max_RQI) * 0.5) + (((Roam_Freq + Max—Freq) * Max_RQI ) * 0.2) + (((Retx_Rate 4- Max_Retx_Rate) * Max_RQI ) * 0.2) + (((Avg_RSSI_ Variance + Max_RSSI-Variance) * Max-RQI ) * 0.1), (2) where RQI is the radio quality indicator value; QBSS is the service quality value of the basic service unit; RSSI is the received signal strength indicator value; Max_RQI = 100; 'Max_QBSS = 100; Max_RQI: RQI maximum value; Max_QBSS : QBSS maximum; Avg_QBSS: QBSS average; Max_Freq: maximum roaming limit; Roam_Freq: number of current roaming of mobile terminal devices; Max_Retx_Rate: maximum packet transmission failure rate; Retx Rate: current packet transmission failure rate of mobile terminal equipment; 25 201001942 Max_RSSI_Variance : Maximum value of RSSI change rate of base station area; Avg- RSSI_Variance : Average value of RSSI change rate of base station area. 14. The roaming method of claim 13, wherein the different radio quality indicator values identify different communication environment states, and the communication environment state includes a normal state, a high traffic state, and an interference state. 15. The roaming method of claim 14, wherein the roaming adjustment module presets a first preset value and a second preset value, and the first preset value is greater than the second preset a value, if the radio quality indicator value is greater than or equal to the first preset value, the communication environment state of the current base station is in a normal state, and the communication environment quality is normal; if the radio quality indicator value is greater than or equal to the second preset value And less than the first preset value, the communication environment state of the current base station is in a high traffic state, and the communication environment quality is relatively poor; if the radio quality indication value is less than the second preset value, the current base station The communication environment state is in an interference state, and the communication environment quality is very poor. 16. The roaming method of claim 9, wherein the roaming threshold includes a difference between a target signal strength of the target base station and the current base station after the mobile terminal device roams, and a basic service unit The difference in service quality. 26