TWI356602B - Mobile terminal device and roaming method thereof - Google Patents

Description

Γ 356602 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 upper network 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 has better network quality than the current network as the target of roaming, and the mobile terminal device continuously scans at a fixed frequency during the roaming process. The target base station 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 device. 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 communicating according to a plurality of base station communication environments Γ 356602 • parameters roaming from a current base station to a target base station, the mobile terminal device comprising: a detection module, configured to detect the plurality of base stations within a predetermined detection time a current communication environment parameter and a roaming frequency and a packet transmission failure rate of the mobile terminal device; a roaming adjustment module, configured to receive a current communication environment parameter of the plurality of base stations, and a roaming frequency and a packet transmission failure rate of the mobile terminal device, and Calculating a Radio Quality Index (RQI) value, and adjusting a roaming threshold of the current base station according to the RQI value; a position detecting module, configured to receive an RQI value of the roaming adjustment module, and Calculating 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 base station sent by the detecting module Current communication environment parameters and roaming frequency and packet transmission failure rate of the mobile terminal device, And receiving the UMI value sent by the location detection 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 decision module determines that the When the target base station of the roaming condition corresponding to the UMI value is received, the roaming execution command sent by the roaming decision module and the Received Signal Strength Indication (RSSI) value of the target base station are disconnected, and the mobile terminal device is disconnected. Communicate with the current base station and establish communication between the mobile terminal device and the target base station. 9 1356602 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 whether the module determines whether there is a target base station that satisfies the roaming condition corresponding to the UMI value; and If there is a target base station that satisfies the roaming condition, the roaming execution module receives the roaming execution command sent by the roaming decision module, and the received signal strength indication (RSI) value of the target base station is disconnected. 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. 1356602 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 value of the U ΜI, and the roaming decision module determines whether there is a target base that satisfies the roaming condition corresponding to the UMI value. The mobile station 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 of the mobile terminal device by adjusting the scanning frequency. Energy consumption in the process. [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 this 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 11 356 602 602, a 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 parameters of the base station area 100 include a Quality of Service Basic Service Set (QBSS) of the base station area 100 and a 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 the working stability of each base station is identified. 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 12 1356602 • the number of failures in the voice operation time, and the mobile terminal device 200 is identified to communicate with the base station (in the present embodiment, the base station 110) corresponding to the communication. The connection stability is higher, and the higher the packet transmission failure rate of the mobile terminal device 200, the worse the communication stability between 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 a current communication environment parameter of the base station area 100 sent by the detection module 210, a roaming frequency of the mobile terminal device 200, and a packet transmission failure rate, and calculate a radio quality indicator ( The Radio Quality Index (RQI) value, and adjusts the roaming threshold (Roaming Threshold) of the base station in communication with the mobile terminal device 200 based on the calculated RQI value. In this 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 -τ Max_Freq) * Max RQI ) * 0.2) + (((Retx_Rate + Max - Retx - Rate) * Max - RQI ) * 0.2) + (((Avg_RSSI_Variance + Max_RSSI_Variance) * Max - RQI ) * 0.1) (2) where

Max_RQI : RQI maximum;

Max QBSS : QBSS maximum; 13 1356602

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 1;

Avg_RSSI_Variance : The average of the RSSI rate of change in the base station area. The value of Max_RQI is preset to 1〇〇, 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. Roam_Freq detects the number of times the mobile terminal device 200 actually roams during the system operating time within the predetermined detection time by the detecting module 210. Max_Retx_Rate is the maximum packet transmission failure rate of the mobile terminal device 200 during the voice working 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 in the base station area 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 interference 1356602 ' state (or a severe interference state). The two preset values 40, 70 are preset in the roaming adjustment module 220. If the RQI value is greater than or equal to the preset value 70, the communication environment state of the base station area 100 is in a normal state, and the communication environment quality is normal; If the RQI value is greater than or equal to the preset value 40 and less than the preset value 70, the communication environment state of the base station area 100 is in a high traffic state, and the communication environment quality is relatively poor; if the RQI value is less than the preset value 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 _ 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 RQI value. If the RQI value is less than 70, the roaming adjustment module 220 increases the roaming threshold value of the base station 110 in communication with the mobile terminal device 200. The smaller the RQI value, the higher the roaming threshold will be adjusted. The roaming threshold includes a difference between the target base station of the mobile terminal device 200 after roaming and the RSSI of the base station 110 in communication with the mobile terminal device 200 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 location detection module 230 calculates a user movement index (User Movement Index, 15 Γ 356602 UMI) value according to the RQI value of the roaming adjustment module 220, and adjusts the mobile terminal device 200 to scan the target base station according to the UMI value. frequency. In the present embodiment, 'different UMI values identify different user movement states', and the user movement states include a stationary state, a walking state, and a running state. If the mobile state of the user is a static state, the mobile terminal device 2 and the base station area 1 are stable in communication signals, and the standby target base station can be found by shortening the scanning frequency, that is, expanding the scanning interval, if the user moves the state to walk. The status 'because the user does not move very fast, the mobile terminal/device 200 and the base station area 1〇〇 communication signal does not rapidly weaken, and the scan frequency of the scanning frequency between the stationary state and the running state can be adjusted. If the user moves to the running state, because the user moves quickly, the mobile terminal device 2 and the base station region 1 are rapidly weakened or even interrupted. At this time, the mobile terminal device 2 needs The alternate target base station is quickly sought, so a higher scanning frequency can be set to cause the mobile terminal device 200 to quickly roam to the target base station. Since the above two states use different scanning frequencies, and the prior art uses only one solid frequency scanning, the present invention can effectively save power. The roaming decision module 240 is configured to receive the current communication environment parameter of the base station area 1 and the roaming frequency of the mobile terminal device 200, and receive the position detection module 23 to send The roaming decision module 240 is configured to determine whether there is a target base station that satisfies the roaming condition corresponding to the .UMI value, and if there is a target base station that satisfies the UMI corresponding no-synchronization condition, the roaming decision mode The group 24 sends a roaming execution command to the roaming execution module 25, notifying the roaming execution module 16 1356602 250 to establish a connection with the target base station; if there is no target base station that satisfies the roaming condition corresponding to the UMI value, Then 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 station area 100 according to the RQI value, and sends the RQI value to the position detection module. 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 丄 (10) 602 Step S6: If there is a target base that satisfies the roaming condition corresponding to the UMI, the roaming execution module 25 receives the execution command of the roaming decision module, and disconnects the mobile terminal device. 200 communicates with the base station, and establishes communication between the mobile terminal device 2 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. The mobile terminal device 200 and the method for roaming by using the communication environment parameters of the plurality of base stations, the mobile terminal device 200 can successfully roam to the target base station by adjusting the frequency of the mobile terminal device 2 to scan the target base station The mobile terminal device automatically adjusts the frequency of scanning the target base station according to the movement state of the user during the roaming process, and reduces the energy consumption during the roaming process of the mobile terminal device by adjusting the scanning frequency. In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. It is to be understood that the above description is only the embodiment of the present invention, and those skilled in the art that are skilled in the art are entitled to the equivalents of 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. 2 is a block diagram of a preferred embodiment of a mobile terminal device of the present invention. 3 is a flow chart of a preferred embodiment of the roaming method of the mobile terminal device of FIG. 1. [Description of main component symbols] Base station area 1〇〇 Mobile terminal equipment 200 (S) 18 Γ 356602 Base station 110, 120, 130 detection module 210 Roaming adjustment module 220 Position detection module 230 Roaming decision module 240 Roaming execution Module 250

C S ) 19

Claims (1)

Γ 356602 X. Patent Application Scope 1. A mobile terminal device 'for roaming from a current base station to a target base station according to a communication environment parameter of a plurality of base stations, the mobile terminal device comprising: a detection module 'for use in a predetermined detection time Detecting a current communication environment parameter of the plurality of base stations and a roaming frequency and a packet transmission failure rate of the mobile terminal device; and a roaming adjustment module, configured to receive a current communication environment parameter of the plurality of base stations and a roaming frequency of the mobile terminal device and The packet transmission failure rate, and the radio quality indicator value is calculated, and the current base station roaming threshold is adjusted according to the radio quality indicator value; the location detection module is configured to receive the radio quality indicator value of the roaming adjustment module And calculating a user movement index value, and adjusting a frequency of the mobile terminal device scanning the target base station according to the user movement index value. The roaming decision module is configured to receive the current base station sent by the detection module. Ittfl environmental parameters and the frequency of the device and the failure rate of the device And the location _ module sends the engraving mobile phone f, and determines that the target base station that satisfies the user mobile index value component; and the tour bar roaming execution module is used to determine the roaming mode: The target base of the roaming condition of the mobile index is 4 = the roaming decision mode (4) is sent (10) the execution command (4) receives the received signal strength indication value, disconnects the communication of the node μ, and establishes: the mobile terminal device and The current base station 7 is configured as a mobile terminal set by the bite terminal device and the target base station. 20 Γ 356602 • 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 change rate of the received signal strength indications of the base stations. The service quality value identifiers of the basic service units of the base stations are The base station channel utilization rate and the load amount of each base station, the received signal strength indication change rate is the amount of change of each base station in the detection time, and the working stability of each base station is identified. 3. The mobile terminal device of claim 1, wherein the mobile terminal device roaming frequency is detected by the detecting module within a predetermined detection time_the mobile terminal device roaming during a system operating time of the mobile terminal device The number of times, the roaming frequency of the mobile terminal device identifies the communication stability of the mobile terminal device and the current base station. The higher the roaming frequency of the mobile terminal device, the worse the communication stability between the mobile terminal device and the current base station. 4. The mobile terminal device of claim 1, wherein the packet transmission failure rate of the mobile terminal device is a number of failed packet transmissions during a 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 Fieq) * 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 Γ3 56602 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 value 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 one RSSI-Variance: The maximum RSSI rate of change in the base station area; Avg-RSSI-Variance: The average 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 state of the current base station is in the positive 22 1356602-normal state, and the communication environment quality is normal; if the radio quality indicator value is greater than or equal to If the second preset value is smaller 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 indicator value is less than the second preset value, The communication environment status of the current base station is in an interference state, and the communication environment quality is very poor. 8. The mobile terminal device as claimed in claim 1, wherein the roaming threshold value comprises 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 value The difference in service quality between service units. 9: A roaming method for a mobile terminal device according to the invention of the invention, comprising the following steps: the detecting module detects a current communication environment parameter of the base station area and the mobile terminal device in a predetermined detection time Roaming frequency and packet transmission failure rate; X parameter detection; sending current communication environment parameters of the base station area and roaming frequency and packet transmission failure rate of the mobile terminal device to the roaming adjustment module and the roaming decision module; The adjustment module obtains a radio quality indicator value by calculating current communication environment parameters of all base stations, and adjusts a roaming threshold value of the base station area according to the radio quality indicator value, and sends the radio indication value to the position detection module. The location debt test module receives the radio quality production value of the roaming adjustment module and calculates a user mobile finger value according to the radio quality indicator value and according to the frequency of the user base station ; mobile index value county (4) equipment scan target correspondence =: = have r - 』 = = = the target of the target ..., And performing roaming hiccup μ mesh ▽ transmission of command and the target base station receives the signal strength indicator Base = message, and the mobile terminal i~ has a target base station that satisfies the navigation condition corresponding to the user's mobile index value, and the operation ends. Π)······································································································ Rate, the service quality value of the basic service units of the base stations identifies the utilization rate of each base station channel and the load amount of each base station, and the received signal strength indicator changes The rate of change of each base station during the detection time is used to identify the operational stability of each base station. 11. The roaming method of claim 9, wherein the mobile terminal does not have a hard-running frequency for detecting, by the detecting module, a system operating time of the mobile terminal device at the calling terminal device within a predetermined detection time. The number of intra-roamings' The roaming frequency of the mobile terminal device identifies the communication stability between the mobile terminal device and the current base station. The higher the roaming frequency of the mobile terminal device, the worse the communication stability between the mobile terminal device and the current base station. 12. The roaming method according to claim 9, wherein the packet transmission failure rate of the mobile terminal 24 1356602 is a number of times the packet transmission fails during the voice operation time, and identifies the current base of the mobile terminal device and its corresponding communication. Taiwan communication stability. 13. The roaming method according to claim 9, wherein the radio quality indicator value is calculated as: RQI = Max_RQI-iRQI, (1) iRQI = (((Avg_QBSS + Max_QBSS) * Max_RQI) * 0.5) + (((Roam_Freq ^ Max_Freq) * Max_RQI ) * 0.2) + (((Retx-Rate + 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; 1356602 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 pre-predetermined value Setting 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 If the value is 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 indicator 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