JP6491899B2 - Wireless communication method - Google Patents

Description

  The present invention relates to a mobile communication system that covers a certain area with a plurality of base station apparatuses using a plurality of frequencies.

  In data communication using a mobile terminal, it is composed of a communication terminal device that is a mobile terminal, a base station device that is a fixed station, a communication control device that performs mobility management by connecting to a plurality of base station devices, and an external network such as a public network Is done. When the communication terminal apparatus moves, the communication terminal apparatus needs to switch the connection partner from the currently connected base station apparatus to another base station apparatus and continue the end-to-end data communication. This switching operation is called handover and is defined as a basic operation in mobile communication. For example, in mobile communication called LTE, an operation related to handover is described in Non-Patent Document 1 compiled by 3GPP, which is a standardization organization.

  The flow of the handover operation will be briefly described. (A) Quality measurement of signals transmitted from surrounding base station devices by communication terminal devices, (B) Notification of quality measurement results to connected base station devices, (C ) Selection of a handover destination base station device by the connected base station device, (D) C-Plane Connection switching, (E) Data transfer from the handover source base station device to the handover destination base station device, (F ) U-Plane path establishment, (G) Hand over source base station device resource release.

  In packet communication systems and mobile communication systems, data communication such as transmission / reception of mail using a mobile terminal, access to the Internet, and browsing of the web is actively performed. As a recent trend, demand for communication with a large data capacity such as video distribution has increased, and accordingly, the throughput of data communication has increased. In order to cope with such an increase in data capacity, a technique for increasing throughput by using a plurality of different frequencies and performing independent communication using the respective frequencies is being introduced.

  Also, if one area is covered by a plurality of base station devices that serve different frequencies, there is a merit that the fault tolerance is dramatically improved. Even if the base station apparatus # 2-A that provides service at a certain frequency A is interrupted due to a failure or the like, if the base station apparatus # 2-B that provides service at another frequency B in the same area continues the service, The mobile terminal can continue communication. In this case, the processing load of the base station apparatus # 2-B having the frequency B increases compared with the normal time, but the service in the same area seems to continue when viewed from the communication terminal apparatus or the end user. .

  Thus, in the case of a configuration in which a plurality of frequencies are serviced in one area, the handover source base station device and the handover destination base station device may have different frequencies during handover. Generally, in the selection of a base station apparatus at the time of handover, as described in the above example, there are processes (A) to (C), and the surrounding base station apparatus measured by the communication terminal apparatus The base station apparatus that compares the signal reception quality and can determine that the reception quality is the best is selected. However, it is easy to select the former when the frequency of the handover source base station apparatus and the frequency of the handover destination base station apparatus are the same or different. This is firstly to avoid agitation of the load situation at different frequencies due to handover, and secondly, the inter-frequency handover is higher in processing cost than the same frequency handover. This increases the risk of call disconnection due to handover.

3GPP, “Overall description; Stage 2 (Release 10),” TS 36.300, 10.1.2.1 3GPP, “Radio Resource Control (RRC); Protocol specification (Release 10),” TS 36.331, Chapter 5.5.4.

  As described above, a wireless communication system in which the same area is covered by a plurality of base station apparatuses having different frequencies has become common. However, the frequency at which the communication terminal apparatus performs radio communication is determined depending on the radio environment at the start of call connection or at the time of handover. Since this wireless environment is determined by how the communication terminal apparatus moves and how the base station apparatus is installed with radio antennas, the communication terminal apparatus concentrates on a specific frequency, and base stations of different frequencies in the same area. There is also a possibility that the load is uneven among the devices.

  As a wireless carrier, it is not desirable that the load situation is determined only by the behavior of the communication terminal device. Non-Patent Document 2 defines a function of adding an offset value to the radio quality of each frequency when the communication terminal apparatus selects a frequency to be notified. This offset value is included in information broadcast from the base station apparatus to the communication terminal apparatus. Due to the effect of the offset value, the measurement result of a specific base station apparatus is offset in handover destination selection for handover to a specific frequency, and the ease of handover can be manipulated. However, this method only indirectly affects the wireless environment in the communication terminal apparatus, and control is not possible for a large change in the wireless environment that exceeds the offset value. As described above, in the technique described in Non-Patent Document 2, when performing handover, a specific communication terminal device cannot be continued with a base station device having a specific frequency. This is the first problem.

  Various applications are executed on the communication terminal device, and there are cases where the application and the QoS type of wireless communication are related. For example, a VoIP application requires a low-latency QoS type bearer. If the frequency A can be limited to the VoIP application, only the low-latency QoS type can be passed through the backhaul line of the base station apparatus having the frequency A, and carelessness between the best effort packet and the bandwidth guarantee packet is inadvertent. Can be avoided. As described above, when performing a handover, there is currently no means for continuing a radio service at a specific frequency for a specific application. This is the second problem.

  Further, in a case where a communication terminal apparatus that is in radio service at the base station apparatus # 1-A of frequency A performs handover across a plurality of base station apparatuses, an area where there is no coverage of frequency A or frequency A A case is assumed in which the area passes through the area of base station device # 2-A that is in use but is out of service. When a communication terminal apparatus enters the area, the service can be continued by performing inter-frequency handover to the base station apparatus # 2-B of another frequency (for example, frequency B) where the service areas overlap. . However, if the handover is simply a conventional method in which base station apparatuses having the same frequency are selected, then the communication terminal apparatus moves further, and an area (base station) in which service is performed on both frequency A and frequency B is performed. When moving to station apparatuses # 3-A and # 3-B), the same frequency handover is prioritized as described above. Therefore, the communication terminal apparatus is handed over to base station apparatus # 3-B of frequency B. However, when it is desired to selectively use the frequency in the QoS type or to avoid the call being biased to the base station apparatus # 3-B, the handover destination should return to the frequency A. In order to avoid handover to the base station apparatus # 3-B, a load distribution function is considered so that the load between the base station apparatus # 3-A and the base station apparatus # 3-B is equalized. However, there is an adverse effect that the communication terminal apparatus to be handed over from the base station apparatus # 1-B to the base station # 3-B via the base station # 2-B is handed over to the base station # 3-A. Thus, conventionally, no mechanism has been prepared for determining the handover destination frequency based on the past attributes of the terminal. This is the third problem.

  Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.

  A wireless communication method in a wireless communication system having a base station device that communicates with a communication terminal device using a plurality of frequencies, wherein the communication terminal device is connected to a first base station device, and the communication terminal The apparatus measures radio states of a plurality of frequencies used by a second base station apparatus that is a candidate for a handover destination, transmits measurement results to the first base station apparatus, and the first base station apparatus Then, based on the information belonging to the communication terminal device, a first priority table relating to the frequency at the time of performing the handover is created, and the first base station device determines the second priority based on the measurement result. A second priority table relating to a plurality of frequencies used by the base station apparatus, and the first base station apparatus uses the first priority table and the second priority table to Frequency when performing handover And a third priority table that associates the identifier of the second base station device with the priority, and the first base station device performs the handover based on the third priority table. A wireless communication method is characterized in that a frequency is determined with a second base station apparatus to be a destination.

  In a wireless communication system that covers the same area with a plurality of base station apparatuses having different frequencies, a frequency priority order of a handover destination base station apparatus is determined on the basis of information belonging to a communication terminal apparatus. The base station apparatus can provide a radio service at a specific frequency.

  By using the QoS Type assigned to Bearer as information belonging to the communication terminal device, a communication terminal device using a specific application (for example, VoIP) whose Bearer QoS type is limited can be used as a base station having a specific frequency. The apparatus can provide a wireless service with a higher priority.

  A case where a communication terminal apparatus that is performing radio service at frequency A crosses over a plurality of base station apparatuses by using the frequency of the base station apparatus before handover to a certain base station apparatus as information belonging to the communication terminal apparatus Thus, it is possible to provide a mechanism for handing over to the original frequency A with high priority after passing through an area where there is no coverage of the frequency A or an area of the base station apparatus that is out of service.

1 is a configuration example of a communication system. It is an example of a functional structure of a communication terminal device. It is an example of a functional structure of a base station apparatus. It is a software structural example of a base station apparatus. It is an example of the database which a base station apparatus manages. It is an example of the database which a base station apparatus manages. It is an example of the message which a base station apparatus receives. It is an example of the message which a base station apparatus receives. It is an example of a structure of the data temporarily produced with a base station apparatus. It is an example of the operation | movement flow of a base station apparatus. It is a detail of the example of the operation | movement flow of a base station apparatus. It is a detail of the example of the operation | movement flow of a base station apparatus.

(System configuration)
A first embodiment of a wireless communication system to which the present invention is applied will be described in detail below with reference to the drawings.

  In the following embodiment, when necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. Is related to some or all of the other modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), particularly when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and it may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps) are not necessarily essential unless explicitly stated or considered to be clearly essential in principle. Needless to say.

  FIG. 1 is a network configuration diagram illustrating a configuration example of a communication system using a communication terminal device (wireless communication terminal) and a base station device according to the present embodiment.

  A communication terminal device 100 that is a terminal owned by a subscriber communicates with the base station device 200 through a wireless link. FIG. 1 shows six base station apparatuses. In this configuration example, three base station apparatuses having frequency A (200-1, 200-2, 200-3) cover three areas, and three base station apparatuses having frequency B (200- 4, 200-5, 200-6), covering the same three areas so as to overlap. Base station apparatus 200-1 and base station apparatus 200-4 cover the same area, base station apparatus 200-2 and base station apparatus 200-5 cover the same area, base station apparatus 200-3 and base station apparatus 200-6 shows an example of covering the same area. Base station apparatus 200-1 and base station apparatus 200-4 may be physically different base station apparatuses, or base station apparatus 200-1 and base station apparatus 200-4 may be the same base station apparatus. Thus, a plurality of frequencies A and B may be used. The same applies to the other base station apparatuses 200-2 to 200-6. A plurality of base station apparatuses 200 are connected to the communication control apparatus 300 via the Router 400 and are controlled thereby. The communication control apparatus 300 has a mobility function for controlling which base station apparatus 200 the terminal 100 is connected to. In addition, the base station apparatuses 200 are connected to each other via the Router 400 and can communicate with each other.

  In the following description, the communication system shown in FIG. 1 is taken as an example.

  FIG. 2 is a block diagram illustrating a configuration example of the communication terminal device 100. FIG. 2 is a block diagram showing a hardware configuration of communication terminal apparatus 100. Specifically, an antenna 110 that transmits and receives radio signals, an RF unit 120 that converts radio signals into electrical signals, a communication processing unit 130 that performs predetermined communication processing (signal termination, protocol conversion, fault monitoring, etc.) on electrical signals, The peripheral device unit 140 inputs and outputs signals transmitted and received by the terminal owner, and the control unit 150 controls the communication terminal device 100 as a whole. The peripheral device unit 140 includes a microphone 141 for inputting sound, a speaker 142 for outputting sound, a display 143 for displaying characters and images, and a key 144 for inputting data and control signals (designating a connection destination, etc.). . The control unit 150 also includes a CPU 160 that is a processor that controls the operation of the communication terminal apparatus 100 as a whole, an MM 170 that is a memory for storing operation programs and various data necessary for the operation, and an I / O 180 that transmits and receives signals to and from external devices. And are provided. The control line 190 connects the blocks described above. Communication terminal apparatus 100 observes radio states of a plurality of frequencies of surrounding base station apparatuses that are candidates for a handover destination, and transmits the observation results to the connected base station apparatus. Specifically, the quality (for example, reception intensity) of the signal transmitted by the surrounding base station apparatus is measured, and the measurement result is transmitted to the connected base station apparatus. A configuration example of the measurement result transmitted to the base station apparatus will be described later with reference to FIG.

  FIG. 3 is a block diagram showing a hardware configuration of base station apparatus 200. Specifically, an antenna 210 that transmits and receives radio signals, an RF unit 220 that converts radio signals into electrical signals, a communication processing unit 230 that performs predetermined communication processing (signal termination, protocol conversion, fault monitoring, etc.) on electrical signals, The communication control device 300 includes an interface 240 that transmits and receives signals, and a control unit 250 that controls the entire base station device 200. The control unit 250 includes a CPU 260 that is a processor that controls the operation of the entire base station apparatus 200, an MM 270 that is a memory that stores operation programs and various data necessary for the operation, and an I / O 280 that transmits and receives signals to and from external devices. Provided. The control line 290 connects the blocks described above.

FIG. 4 is a software configuration diagram illustrating a software configuration example of the base station apparatus 200. The control unit 250 communicates with the base station apparatus 200 and the communication control apparatus 300, transmits / receives a handover instruction transmission / reception unit 2501, a terminal information storage unit 2502 that collects and stores information belonging to the communication terminal device, and a communication The measurement result notification receiving unit 2503 that performs wireless communication with the terminal device 100 to receive the measurement result notification, the measurement result notification from the measurement result notification receiving unit 2503, and the information that belongs to the communication terminal device from the terminal information storage unit 2502 And a frequency candidate analyzing unit 2504 for analyzing the frequency candidate of the handover destination and a handover destination determining unit 2505 for receiving information from the frequency candidate analyzing unit 2504 and determining the base station apparatus of the handover destination.
(Database configuration)
FIG. 5 shows a configuration example of the database 600 managed by the base station apparatus 200. The database 600 includes a terminal information storage database 610 and a QoS type database 620. The terminal information storage database 610 held for each base station apparatus 200 is stored in the terminal information storage unit 2502. In the terminal information storage database 610, information of a plurality of communication terminal devices is stored for each communication terminal device (6101, 6102, 6103). The information 6101 of a certain communication terminal device includes a communication terminal device ID 61011 for identifying the communication terminal device, and communication terminal device attribution information 61012 for storing information belonging to the communication terminal device.

  The QoS type database 620 is set by the communication operator operator and stored in the terminal information storage unit 2502. The QoS type database 620 registers a frequency corresponding to each QoS type (6201, 6202, 6203). One priority 62012 and a plurality of frequencies (62013, 62014) can be registered for one QoS type 62011.

FIG. 6 is an example in which the communication terminal device attribution information 61010 is detailed. The communication terminal device attribution information 61012 includes information on a plurality of bearers (610121, 610122, and 610123). A certain bearer information 610121 includes a bearer ID 610211 and a QoS type 6101212.
(Composition of communication message)
FIG. 7 shows a configuration example of a measurement result notification 700 transmitted from the communication terminal apparatus 100 to the base station apparatus 200. The measurement result notification 700 can include a plurality of pieces of information on base station apparatuses that can receive radio signals by the communication terminal apparatus 100 (7001, 7002). The information 7001 of a certain base station apparatus includes a base station apparatus ID 70010 that can specify the base station apparatus, a frequency 70011, and a communication quality 70012. Note that the measurement result notification 700 may include information other than that described in FIG.

FIG. 8 shows a configuration example of a handover request notification 800 transmitted from the handover source base station apparatus 200 or the communication control apparatus 300 to the handover destination base station apparatus 200. The handover request notification 800 includes a communication terminal device ID 8001 for identifying a communication terminal device to be handed over, and communication terminal device attribution information 8002 for storing information belonging to the communication terminal device. The communication terminal apparatus belonging information 8002 may be, for example, the frequency 80021 of the handover source base station apparatus 200. Note that the handover request notification 800 may include information other than that shown in FIG.
(Priority table by frequency)
FIG. 9 is an example of temporary data that the base station apparatus 200 holds in the course of processing steps to be described later. The priority table 900 includes a priority table (A) 910, a priority table (B) 920, and a priority table (C) 930. The priority table (A) 910 is composed of combinations of frequencies and priority numbers (9101, 9102, 9103). The priority table (A) 910 is created for each communication terminal device based on the contents of the terminal information storage database 610. The priority table (B) 920 includes a set of a frequency 92011, a signal reception quality 92012, and a base station apparatus ID 92013. Priorities among the groups are determined by sorting based on the received signal quality 92012. The priority table (C) 930 is created from the priority table (A) 910 and the priority table (B) 920. The frequencies in the priority table (A) 910 are sorted as the first priority. In this example, among the frequencies in the priority table (A) 910, the highest priority is given to the frequency A (93011), which is the highest priority frequency. When there are a plurality of base station apparatus IDs in each frequency (for example, 93012), the signal reception quality (920122) is sorted and created as the second priority. For example, FIG. 9 shows an example in which there are three base station apparatus IDs (920123) using the frequency A, and the higher the signal reception quality measured by the communication terminal apparatus, the higher the priority. . In addition, there may be no base station apparatus (for example, 93032) at a certain frequency (for example, frequency C93031).

  Next, an example of a first wireless communication system that determines a handover destination using information belonging to a communication terminal apparatus in a communication system to which the present invention is applied will be described.

  (1) FIG. 10 is a processing example performed by the base station apparatus 200. Base station apparatus 200 collects information belonging to the communication terminal apparatus in terminal information storage section 2502 and stores it in terminal information storage database 610 (P-100). The information belonging to the communication terminal apparatus may be obtained from the communication terminal apparatus 100 when the communication terminal apparatus 100 initially connects to the base station apparatus 200, or received from the communication control apparatus 300 or another higher-level apparatus. May be.

  (2) The base station apparatus 200 receives information belonging to the communication terminal apparatus from the terminal information accumulation database 610 in the frequency candidate analysis unit 2504, and prioritizes the frequency candidates when performing wireless service for the communication terminal apparatus A table (A) 910 is created (P-110). This step is performed for all communication terminal apparatuses connected to the base station apparatus 200, and a priority order table (A) 910 for each communication terminal apparatus is created.

  (3) Base station apparatus 200 receives, as measurement result notification 700, signal reception quality with each base station apparatus measured by the communication terminal apparatus at measurement result notification receiving section 2503 (P-120).

  (4) The base station apparatus 200 receives the measurement result notification 700 from the measurement result notification reception unit 2503 in the frequency candidate analysis unit 2504, and determines the priority order table (B) 920 of the frequency candidates (P-130). Specifically, for each base station apparatus in the measurement result notification 700, the signal reception quality is compared, and the base station apparatuses are sorted in order of the reception quality.

  (5) The base station apparatus 200 uses the priority candidate table (A) 910 calculated in P-110 and the priority table (B) 920 calculated in P-130 in the handover destination determination unit 2505 to generate a frequency candidate analysis unit. Received from 2504, the priority table (C) 930 is determined (P-140).

  Step P-140 will be specifically described with reference to FIG. The corresponding priority order table (A) 910 is specified for the target communication terminal device of the measurement result notification 700 received in P-130 (P-1401). Next, the priority table (B) is sorted in the order of high priority by using the frequency as the first key. The frequency prioritization at this time follows the priority number corresponding to the frequency on the priority table (A) 910 (P-1402). When a frequency not in the priority table (A) 910 is in the priority table (B) 920, the frequency is treated as the lowest priority. Finally, the frequencies having a plurality of base station apparatuses within the same frequency are sorted in the order of high priority using the signal reception quality 92012 as the second key (P-1403).

  (6) Base station apparatus 200 determines base station apparatus 200 with the highest priority in the priority order table (C) 930 calculated in P-140 as a handover destination, and performs handover (P-150). ).

  In this way, by determining the frequency priority order of the handover destination base station apparatus based on the information belonging to the communication terminal apparatus, the base station apparatus provides a radio service to the communication terminal apparatus using a specific frequency. Can be provided continuously.

  Next, a second embodiment of the wireless communication system for determining a handover destination using information belonging to a communication terminal apparatus in a communication system to which the present invention is applied will be described with reference to FIG.

  In this embodiment, bearer information is used as information belonging to a communication terminal device. The bearer information can be generated or updated by the base station apparatus 200 when a bearer is secured between the communication terminal apparatus 100 and the base station apparatus 200.

  (1 ′) Bearer information set between the communication terminal apparatus 100 and the base station apparatus 200 is adopted as information belonging to the communication terminal apparatus stored in the terminal information accumulation database 610 (610121, 610122, 610123). The bearer information 610121 includes a bearer ID 610211 for identifying a bearer and a QoS type 6101212 indicating the quality of service to be provided to the bearer.

  (2 ′) The base station apparatus 200 stores the contents of the QoS type database 620 previously set by the communication operator through the interface 240 and the terminal information storage database 610 based on the terminal information storage database 610. A priority table (A) 910 is created for each piece of information belonging to each registered communication terminal device. Specifically, the QoS type database 620 is searched for each of the terminal information accumulation database 610 of the communication terminal apparatus 100 based on the QoS type 6101212 of each bearer that the communication terminal apparatus 100 has. When there is a matched QoS type, the frequencies 62013, 62014... Are registered in the priority table (A) 910 together with the priority 62012 (P-1101). When extraction from the QoS type database 620 is completed for all bearers of the communication terminal device 100, the priority order table (A) 910 is sorted in order of high priority using the frequency as a key. The priority order at that time follows the priority 62012 of the QoS type database 620 (P-1102).

  The subsequent processing is the same as (3) to (6) described in the first embodiment.

  As a result, the radio service can be provided by the base station apparatus 200 having an appropriate frequency according to the application adopted by the communication terminal apparatus. Therefore, the second problem can be solved by this method.

  Next, a description will be given of a third embodiment of a wireless communication system that determines a handover destination using information belonging to a communication terminal apparatus in a communication system to which the present invention is applied. In the present embodiment, it is assumed that the base station apparatus 200-2 in FIG. 1 is out of service and the communication terminal apparatus 100 connected to the base station apparatus 200-1 is the base station apparatus 200-. Next, a radio communication scheme in the base station apparatus 200-5 after handover between frequencies will be described in FIG. By using this method, the communication terminal apparatus can be handed over to the base station apparatus 200-3 instead of the base station apparatus 200-6 using the same frequency as the base station apparatus 200-5.

  In this embodiment, information relating to the frequency of the handover source base station apparatus is used as the information belonging to the communication terminal apparatus. Information regarding the frequency of the handover source base station apparatus can be generated by the handover destination base station apparatus 200 upon receiving a notification from the handover source base station apparatus 200 during the handover.

  (1 ″) As information belonging to the communication terminal device to be stored in the terminal information storage database 610 of the base station device 200-5, as a previous handover operation, when the inter-frequency handover is performed from the base station device 200-1. Specifically, the communication result is used, specifically, a handover request notification 800 transmitted from the base station apparatus 200-1 to the base station apparatus 200-5 is used.

  (2 ″) The base station apparatus 200-5 creates a priority table (A) 910 for each communication terminal apparatus information registered in the terminal information storage database 610 based on the terminal information storage database 610. There is only one entry (only 9101) in the priority table (A) 910 created in this embodiment, that is, only the frequency used by the base station apparatus 200-1 that is the handover source. .

  The subsequent processing is the same as (3) to (6) described in the first embodiment.

  As a result, the communication terminal apparatus 100 connected to the base station apparatus 200-1 using the frequency A inevitably has a base station apparatus 200-5 using the frequency B because the service of the base station apparatus 200-2 is interrupted. Is handed over to the base station apparatus 200-3 using the frequency A by this method. As a result, the communication terminal apparatus can return to the frequency A that originally received the wireless service. Therefore, the third problem can be solved by this method.

  In each embodiment, the example in which the base station apparatus 200 determines the frequency with the base station apparatus that is the handover destination has been described. However, the base station apparatus 200 transmits the information belonging to the communication terminal apparatus and the measurement result measured by the communication terminal apparatus to the communication control apparatus 300, and the communication control apparatus 300 determines the base station apparatus to be a handover destination and the frequency. May be.

100 communication terminal apparatus 200 base station apparatus 300 communication control apparatus 400 Router
600 Database 700 Measurement result notification 800 Handover request notification 900 Priority table The following are typical examples of aspects of the present invention other than those described in the claims.

  1. In a wireless communication system including a first wireless base station device that communicates with a wireless terminal device with a plurality of frequencies, and a second wireless base station device in which at least some of the frequencies differ from the first wireless base station device In the method in which the radio terminal apparatus performs handover from the first radio base station apparatus to the second radio base station apparatus, the communication terminal apparatus sets radio states of a plurality of frequencies of the second radio base station apparatus that is a handover destination. Observe and transmit the measurement result including the radio wave condition to the first radio base station apparatus, and the first radio base station as the handover source performs the handover from the information belonging to the radio terminal apparatus obtained in advance. Create a list of priorities for frequencies, and select frequencies that can be selected as handover candidates from the list of measurement results for the second radio base station device obtained from the terminal. And a handover method characterized in that from among the candidates of the selected frequency to determine the frequency of performing handover according to the list of priorities.

  2. In the handover method described in the above item 1, the information belonging to the wireless terminal device obtained in advance relates to the highest class of the QoS class currently used by the terminal that performs the handover, and the priority of the frequency to be selected A handover method characterized by creating a list of ranks.

  3. In the handover method described in 1 above, the information belonging to the wireless terminal device obtained in advance is the frequency used in the past when the wireless terminal has handed over from another wireless base station in the past. A handover method characterized in that a frequency used in the past is set to a higher priority.

Claims (1)

A wireless communication method in a wireless communication system having a base station device that communicates with a communication terminal device using a plurality of frequencies,
The communication terminal device is connected to a first base station device,
The communication terminal apparatus measures radio states of a plurality of frequencies used by a second base station apparatus that is a candidate for a handover destination, and transmits a measurement result to the first base station apparatus.
The first base station device creates a first priority table related to frequencies when performing the handover based on information belonging to the communication terminal device,
The first base station apparatus creates a second priority table for a plurality of frequencies used by the second base station apparatus based on the measurement result,
The first base station apparatus uses the first priority table and the second priority table to determine a frequency for performing the handover, an identifier of the second base station apparatus, and a priority. Create a third priority table associated with it,
The first base station apparatus determines a frequency with the second base station apparatus to be the handover destination based on the third priority table,
The information belonging to the communication terminal device is information related to the frequency of the handover source base station device,
The radio communication method according to claim 1, wherein the first base station apparatus creates the first priority table using information related to a frequency of the base station apparatus that is the handover source.

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