JP4063141B2 - Wireless relay device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wireless relay device used in a wireless communication system such as a PHS (Personal Handy phone System).
[0002]
[Prior art]
Currently, a 4-channel multiplexed TDMA-TDD (Time Division Multi Access-Time Division Duplex) system is adopted as a packet communication system between a PHS base station and a mobile station. In the above method, as shown in FIG. 2, one frame having a time length of 5 msec is used as one unit of transmission signal in one base station. Set up Further, one slot divided into 8 equals is defined as 1 slot (time length 0.625 msec). Then, 4 slots in one frame are allocated to transmission signals from the base station to the mobile station (hereinafter referred to as “downlink”), and the remaining 4 slots are transmitted from the mobile station to the base station (hereinafter referred to as “uplink”). Assigned to the transmitted signal. That is, one base station can theoretically process communication with up to four mobile stations simultaneously. One slot contains 160-bit data, and 160-bit data is transmitted in half duplex every 5 msec between one mobile station and a base station. If viewed per unit time, it is 32 kbit. A communication speed of / sec can be obtained.
[0003]
By the way, in PHS, a radio frequency of 1.9 GHz band is used. For example, since radio waves of a base station installed outdoors are difficult to reach a mobile station in a building, an outdoor base station and an indoor mobile station Conventionally, a wireless relay device that relays each transmitted radio wave has been used (see, for example, Patent Document 1). This wireless relay device creates a data table (ranking table) that shows the ranking of communicable base stations using as an index the reception strength (electric field strength) of radio waves transmitted from the base station at the initial setting after startup. A communication channel is transmitted to the highest-order base station, that is, the base station having the highest radio wave reception intensity, to make a communication request.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-155172 (page 3, FIG. 1)
[0005]
[Problems to be solved by the invention]
Incidentally, in recent years, with the spread of the Internet, the demand for wireless communication systems capable of performing high-speed packet communication has increased, and even in packet communication using the above-described PHS, one mobile station is mutually connected to improve communication speed. By communicating with a plurality of (for example, two) different base stations, a higher speed than when communicating with only one base station (for example, up to 64 kbit / s when communicating with two base stations) sec. communication speed).
[0006]
However, when a radio relay device is interposed between one mobile station and a plurality of base stations, the radio relay device is also regarded as a base station from the mobile station. The base station with which the station communicates directly may overlap. That is, even if a radio relay device that is considered to have the highest reception strength from the viewpoint of the mobile station and a base station that is considered to have the next highest reception strength are selected, the two base stations are actually the same. There is a possibility that communication with only one base station is practically performed, and the original communication speed may not be obtained.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wireless relay that prevents a mobile station from repeatedly selecting the same base station and obtains an intended communication speed. To provide an apparatus.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is used in a radio communication system that performs radio packet communication between a mobile station and a base station using a plurality of time-division multiplexed slots. In a wireless relay device that relays each transmission radio wave between the station and the base station, a data table that represents the ranking of the base station using the radio field intensity of the base station having a slot capable of communication at the initial setting after startup as an index A data table creating means for creating, and a base station selecting means for selecting a relay destination base station that relays transmission data to and from a mobile station with reference to the data table, the base station selecting means comprising: When a plurality of base stations are stored for the same slot in the data table, the base station having the second highest radio wave strength among the plurality of base stations in the slot is assigned to the slot. Against and selects the relay destination.
[0009]
According to a second aspect of the present invention, in the first aspect of the present invention, the base station selecting means includes a plurality of base stations in each slot when there are a plurality of slots storing the plurality of base stations in the data table. A base station having the second highest electric field strength is selected as a relay destination for the slot.
[0010]
According to a third aspect of the present invention, in the second aspect of the present invention, when the base table selecting means has only one slot in which the plurality of base stations are stored in the data table, the plurality of base stations in the slot. The base station with the second highest electric field strength is selected as the relay destination for the slot, and when there are a plurality of the slots, the electric field strength with the second highest electric field strength among the plurality of base stations in each slot is selected. A base station is selected as a relay destination for the slot.
[0011]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the data table creation means divides the electric field strength of the base station into a plurality of levels, and corresponds to the electric field strength of each base station at the time of initial setting. A base station is stored in a hierarchy, and the base station selection means selects the base station of the relay destination from a slot having a large number of base stations stored in a hierarchy having a large electric field strength among a plurality of hierarchies of the data table It is characterized by doing.
[0012]
According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the data table creation means is configured to provide the plurality of base stations when a difference in electric field strength between a plurality of base stations stored in the same slot is smaller than a predetermined threshold value. A base station is deleted from the data table.
[0013]
According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the data table creating means updates the data table when communication between the base station and the mobile station is suspended. Features.
[0014]
The invention of claim 7 is the invention according to any one of claims 1 to 6, wherein when another radio relay apparatus is stored as a base station in a slot in the data table, the other radio relay apparatus is set as a relay destination. Investigation means for investigating the selected base station, wherein the data table creation means includes the base station selected by the other wireless relay device as a relay destination by the investigation means and the other wireless relay device. It is characterized by deleting from the data table.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0016]
(Embodiment 1)
FIG. 1 shows the configuration of a radio relay apparatus C of the present embodiment used for PHS, and is used with public or private base stations (hereinafter referred to as “base stations”) B1, B2,. A wireless circuit comprising an antenna 1 for performing transmission / reception between them, a wireless circuit block 2 including a modem for transmitting / receiving communication data by radio waves through the antenna 1, and a wireless circuit control block 3 for controlling access to the wireless circuit block 2 by time division multiplexing. The communication unit 4 includes a memory 6 composed of a RAM for storing a data table DT described later, and a CPU 5 for reading / writing the memory 6 and controlling the wireless circuit block 2 through the wireless circuit control block 3. . In the figure, Bi (i = 1, 2,..., N) indicates a base station, and A indicates a mobile station (for example, a PHS terminal corresponding to packet communication).
[0017]
Here, the base stations B1,... Around the radio relay apparatus C transmit the signal of the control channel CCH at the same frequency, but the transmission format is at a constant time interval (100 msec in the illustrated example) as shown in FIG. A frame with a certain time width (5 msec width) is set, and a slot (time slot) with a width of 0.625 msec is provided in the frame, and the slot is used for broadcast information of the control channel CCH of each base station B1. A transmission slot for transmitting a data signal is configured, and the radio circuit block 2 of the radio relay apparatus C can receive signals of the control channel CCH of the base station B1. It can be done.
[0018]
Here, in the wireless relay device C of the present embodiment, the broadcast information BCCH transmitted by the control channel CCH is received and analyzed from each base station B1... At the initial setting after activation, and the broadcast information BCCH is transmitted to the mobile station A. When transmitting the data, the CPU 5 checks the strength (electric field strength) of the received radio waves from each base station B1... For each of the four downstream slots, and creates a data table representing the ranking of the base stations using the radio wave intensity as an index. Created and stored in memory 6. That is, in this embodiment, the CPU 5 serves as a data table creation unit. Here, the data table DT corresponds to each base station number (for example, n (maximum 20) base station numbers that can be communicated such that B1 is 1 and B2 is 2) as shown in FIG. A column for entering the ID of the base station B1... And a column for entering the electric field strength of the base station B1... With the ID are provided for each of the slot numbers 1 to 4, and each base station belongs to the same slot number. The IDs of B1... Are arranged in descending order using the electric field strength as an index. Then, the CPU 5 of the wireless relay device C refers to the data table DT stored in the memory 14 and selects a base station B1... As a standby destination (a relay destination that relays transmission data to / from the mobile station A). In this embodiment, the CPU 5 constitutes a base station selection unit.
[0019]
Here, when a plurality of base stations B1... Are stored for the same slot in the data table DT, the CPU 5 as the base station selection means is the second or later among the plurality of base stations B1. Base stations B1... With high radio field strength are selected as relay destinations for the slot. More specifically, in the example of the data table DT shown in FIG. 3, since the most base stations B1... Are stored in the slot with slot number 1 (hereinafter referred to as “first slot”), the first slot , And a base station excluding the base station B1 (ID = XXXXXXXXXX1) having the highest electric field strength among the plurality of base stations B1, B5,..., Bn stored in the first slot. Bi, for example, the second base station B5 (= XXXXXXXXXX5) is selected and determined as a standby destination (relay destination).
[0020]
Therefore, as shown in FIG. 4, the radio relay apparatus C receives, for example, the first slot from the selected base station B5, and transmits the signal of the control channel CCH using the fourth slot, for example. Will communicate directly with the base station B1 having the highest electric field strength after initiating communication with the base station B5 via the wireless relay device C. That is, in the conventional example, since the wireless relay device has selected the base station B1 having the highest electric field strength as the relay destination, the mobile station A overlaps with the base station with which the mobile station A communicates directly, and the desired communication speed cannot be obtained. However, in the present embodiment, as described above, the radio relay apparatus C relays a base station (for example, B5) other than the base station (B1 in the above example) that is considered to have the highest radio wave intensity when viewed from the mobile station A. As a result, it is possible to prevent the mobile station A from selecting the same base station repeatedly and to obtain the desired communication speed.
[0021]
By the way, when there are two or more slots in which a plurality of base stations B1... Are stored in the data table DT, a base station having the second highest electric field strength among the plurality of base stations in the plurality of slots is assigned to the slot. You may make it select as a relay destination with respect to. For example, in the case of the data table DT shown in FIG. 3, a plurality of base stations B1,... Are stored in all four slots, and the CPU 5 takes the second electric field for the first slot and the second slot. Base stations B5 and B6 having high strength are selected as standby base stations. Therefore, as shown in FIG. 5, the radio relay apparatus C transmits the signal of the control channel CCH using the selected base stations B5 and B6 and the third and fourth slots, and the mobile station A transmits the radio relay apparatus C After the communication is indirectly started with the base stations B5 and B6, the direct communication is performed with the base stations B1 and B2 having the highest electric field strength in the first and second slots. In this way, if the radio relay apparatus C selects a plurality of base stations as standby destinations (relay destinations), the number of base stations having a large electric field strength when viewed from the mobile station A increases, and the base stations B1,. There is an advantage that communication between the two becomes stable.
[0022]
However, the communication status between the wireless relay device C and the base station B1 is very different. For example, there may be only five base stations B1 that can communicate as shown in FIG. As shown in FIG. 5B, there are cases where communication with nine base stations B1... Is possible, and each data table has only one slot for storing a plurality of base stations B1. In some cases (such as in FIG. 6A), there are a plurality of slots in which a plurality of base stations B1... Are stored (for example, in the case illustrated in FIG. 6B). 6 (a) and 6 (b), the base stations B1... Arranged in the vertical direction are the base stations B1... That can communicate in the first slot, the second slot, the third slot, and the fourth slot in order from the leftmost column. Represents a set.
[0023]
Therefore, in the CPU 5 which is the base station selection means, when there is only one slot in which the plurality of base stations B1... Are stored in the data table, the electric field is applied to the second and subsequent base stations among the plurality of base stations B1. When a base station having a high strength is selected as a relay destination for the slot and there are a plurality of slots storing a plurality of base stations B1,..., The electric field strength of the second and subsequent base stations among the plurality of base stations in each slot is It is desirable that a large base station is selected as a relay destination for the slot, and an appropriate number of base stations B1,.
[0024]
(Embodiment 2)
Since the configuration of the wireless relay device C of this embodiment is the same as that of the first embodiment, illustration and description thereof are omitted.
[0025]
As shown in FIG. 7, the CPU 5 serving as the data table creation means determines the electric field strengths of the base stations B1... From the data table (hereinafter referred to as “first data table”) DT described in the first embodiment. A data table (hereinafter referred to as “second data table”) in which the base stations B1... Are stored in the respective hierarchies S1 to S4 corresponding to the electric field strength of each base station B1. DT2 is created. The thresholds for each of the hierarchies S1 to S4 may be determined based on the electric field strength of each base station B1... In the example shown in FIG. 7, the thresholds for the highest hierarchy S1 and the second hierarchy S2 are 42. The threshold value 34 of the second hierarchy S2 and the third hierarchy S3 is set to 26, and the threshold value of the third hierarchy S3 and the fourth hierarchy S4 is set to 26. That is, a base station having an electric field strength of 42 or more is stored in the highest layer S1, and a base station having an electric field strength of 34 or more and less than 42 is stored in the second layer S2, and the electric field strength is 26 or more and less than 34. The base station is stored in the third hierarchy S3, and the base station whose electric field strength is less than 26 is stored in the fourth hierarchy S4 (see FIG. 7).
[0026]
Then, the CPU 5 as the base station selection means refers to the base station B7 stored in the hierarchy S2 second in the second and fourth slots with the large number of base stations Bi stored with reference to the second data table DT2. B9 is selected as a standby destination (relay destination) and determined.
[0027]
Thus, as shown in FIG. 7, in the first slot, the electric field strength of the first base station B1 is very large (70), and the electric field strength of the second base station B10 is relatively very small (33). In such a case, if the second base station B10 in the first slot is selected as a standby destination (relay destination), the efficiency as the radio relay apparatus C will be reduced. By selecting the relay destination base station Bi from the slots (the second and fourth slots in the above example) having a large number of base stations Bi stored in the layer S1. Therefore, it is possible to avoid a decrease in efficiency due to the selection of the relay destination base station Bi from the slot having a very large difference in electric field strength, and to select an appropriate base station Bi with high accuracy.
[0028]
By the way, since the radio relay apparatus C cannot know the reception intensity of the mobile station A from the base station Bi, for example, as shown in FIG. 8, when viewed from the radio relay apparatus C, the electric field intensity of the base station B4 is that of the base station B6. Although it is larger than the electric field strength, when viewed from the mobile station A, a situation may occur where the electric field strength of the base station B4 is smaller than the electric field strength of the base station B6. Under such circumstances, when the base station B6 having the second electric field strength is selected as the relay destination by the radio relay apparatus C, the mobile station A is the same as the base station B6 having the highest electric field strength for the mobile station A. There is a possibility that the same base station B6 as the relay destination of the relay apparatus C may be selected redundantly. Therefore, the CPU 5 serving as the data table creation means determines the difference in electric field strength between the plurality of base stations B4 and B6 stored in the same slot (the fourth slot in the case of the second data table DT2 shown in FIG. 7) (45−43 = If the plurality of base stations B4 and B6 are deleted from the data table (in this case, the second data table DT2) when 2) is smaller than a predetermined threshold value (for example, 5), In such a situation, it is possible to prevent the mobile station A from selecting the same base station B6 as that of the radio relay apparatus C, thereby improving the accuracy of base station selection.
[0029]
(Embodiment 3)
Since the configuration of the wireless relay device C of this embodiment is the same as that of the first embodiment, illustration and description thereof are omitted. The present embodiment is characterized in that the data table DT or DT2 is updated when the CPU 5 serving as the data table creation means stops communication between the base station B1... And the mobile station A.
[0030]
The CPU 5 relays transmission data between the base station B2 selected based on the data table DTa created at the time of initial setting and the mobile station A by controlling the wireless communication unit 4 as shown in FIG. When the communication between the base station B2 and the mobile station A is suspended for some reason, for example, when the base station B2 suspends transmission for maintenance or the like, or the electric field strength of the transmission radio wave from the base station B2 is When the communication is interrupted due to a drop, the broadcast signal BCCH transmitted from the base stations B1 through the control channel CCH is received in the same procedure as in the initial setting, and the electric field strength of the received radio waves from the base stations B1. Is updated every four slots, and a new data table DTb is created and stored in the memory 6 to update the data table DT or DT2.
[0031]
As described above, in the present embodiment, the CPU 5 serving as the data table creation means updates the data table DT or DT2 when communication between the base station B1... And the mobile station A is suspended. The accuracy of base station selection can be increased compared to the case where the data table is continuously used.
[0032]
(Embodiment 4)
Since the configuration of the radio relay apparatuses C and C ′ of this embodiment is the same as that of the first embodiment, illustration and description thereof are omitted.
[0033]
As shown in FIG. 10, there are two wireless relay apparatuses C and C ′ between the mobile station A and a plurality of base stations B1 to B9, and the same base station B1 to B9 serves as a relay destination candidate for each wireless relay. Consider a case where the data is stored in the data tables DT and DT ′ of the devices C and C ′. Here, FIG. 11 shows the data table DT of the wireless relay device C activated earlier, and FIG. 12 shows the data table DT ′ of the wireless relay device C ′ activated later. However, in each of the data tables DT and DT ′, the electric field strength is divided into four levels of layers S1 to S4 as in the second embodiment. In such a case, if the two radio relay apparatuses C and C ′ select the same base station (for example, B5 and B6), the mobile station A can select any of the two radio relay apparatuses C and C ′. A state where only one of them can communicate is generated. In the present embodiment, the mobile station A can communicate with the two radio relay apparatuses C and C ′ at the same time even in the above-described case, and the details will be described below.
[0034]
Of the two wireless relay devices C and C ′, since the wireless relay device C that has been activated first is also regarded as a base station when viewed from the wireless relay device C ′ that has been activated later, as shown in FIG. Since the wireless relay device C relays the two base stations B5 and B6, it is stored in the data table DT ′ of C ′ as two base stations C1 and C2. That is, in the data table DT ′ of the radio relay apparatus C ′, B5 and C1 and B6 and C2 which are substantially the same base stations are redundantly stored.
[0035]
By the way, the base station Bi transmits the broadcast channel BCCH including its own identification code (calling identification code) at a constant time interval (100 msec interval) in the control channel CCH. This broadcast channel BCCH is a downlink unidirectional channel for broadcasting control information (such as information on the channel structure and system information) from the base station Bi to the mobile station A, and includes a preamble pattern, a unique word for synchronization, a channel type code, It consists of a calling identification code, data (BCCH) and a cyclic error detection code. As shown in FIG. 13, the identification code (calling identification code) for identifying each base station B1... Is a 9-bit operator identification code and Np bit (16 bits in the illustrated example) general call area number. (Obtained from the broadcast information BCCH from the base station Bi) and an additional ID of (33-Np) bits (17 bits in the illustrated example) are included ("second generation cordless telephone system standard (RCR STD-28) "reference).
[0036]
Here, the radio relay apparatuses C and C ′ create their own identification codes by using a part of the identification codes (for example, the 7th to 16th bits of the additional ID) acquired from the relay destination base station. The broadcast channel BCCH of the relay destination base station is relayed to the mobile station A using the identification code. Then, in the CPU 5 of the radio relay apparatus C ′, the base stations having the same 7th to 16th bits of the additional ID included in the received broadcast channel BCCH are regarded as overlapping base station candidates, and FIG. The overlapping candidate list R as shown is created by the CPU 5. That is, in the present embodiment, the CPU 5 becomes the investigation means. If the radio relay apparatus C selects the base stations B5 and B6 as relay destinations as described above, C1 and B5 and C2 and B6 are duplicated as duplication candidates K1 and K2, respectively, as shown in FIG. It is registered in the candidate list R.
[0037]
Here, when viewed from the radio relay apparatus C ′, the radio relay apparatus C is also regarded as a base station. However, any of the base stations of the duplication candidates K1 and K2 registered in the duplication candidate list R in the CPU 5 of the radio relay apparatus C ′. Whether it is the wireless relay device C is confirmed by the following procedure.
[0038]
That is, the CPU 5 of the radio relay apparatus C ′ performs RT (radio management) / MM for the base stations B5, B6, C1, and C2 registered in the duplication candidate list R as duplication candidates K1 and K2, as shown in FIG. A link channel establishment request is transmitted by the (mobility management) protocol. Here, the RT / MM protocol has a plurality of versions (version 1 to version 4) corresponding to the version number of the second generation cordless telephone system standard (the latest standard is the fourth version). When the base station and the mobile station do not match, it is defined that the base station responds to the link channel establishment request from the mobile station, and the CPU 5 of the radio relay apparatus C ′ actually A link channel establishment request in which a fictitious version that does not exist (for example, version 8) is designated as the RT / MM protocol version is transmitted to each of the base stations B5, B6, C1, and C2. Accordingly, in the base stations B5, B6, C1, and C2 that have received the link channel establishment request from the radio relay apparatus C ′, the RT and MM protocol versions do not match. An assignment rejection response should be transmitted to the radio relay apparatus C ′. However, in the wireless relay device C, even if the real reason is that the RT / MM protocol version does not match, it is a specification that returns a link channel assignment rejection response with other reasons. Therefore, in the radio relay apparatus C ′, the returned reason for refusing the link channel assignment is stored in the column of each base station in the duplication candidate list R (see FIG. 14), and for these reasons, the base stations B5 and B6 are wirelessly connected. The relay apparatus C (C1, C2) is identified.
[0039]
Then, the CPU 5 of the radio relay apparatus C ′ deletes the base stations B5, B6, C1, and C2 of the duplication candidates K1 and K2 in the duplication candidate list R created as described above, and updates the data table DT ′ ( 16), by referring to the updated data table DT ′, the base stations (B7 and B8 in the illustrated example) of the standby destination (relay destination) are selected and determined (see FIG. 17).
[0040]
As described above, in the present embodiment, when another wireless relay device C is stored as the base stations C1 and C2 in the slot in the data table DT ′ of the wireless relay device C ′, the other wireless relay device C is the relay destination. The base stations B5 and B6 selected in the above are investigated, and the base stations B5 and B6 and the other radio relay apparatuses C (C1 and C2) are deleted from the data table DT ′. It is possible to prevent the relay device C and the relay destination base stations B5 and B6 from overlapping, thereby improving the accuracy of base station selection. Further, as shown in FIG. 17, since the mobile station A can wait on the different base stations B5, B6, B7, and B8 by the two radio relay apparatuses C and C ′, the base station B1. There is an advantage that the communication is more stable.
[0041]
【The invention's effect】
In the first aspect of the invention, by selecting a base station other than the base station considered to have the highest radio field intensity as viewed from the mobile station as a relay destination, the mobile station selects the same base station repeatedly. Prevents the desired communication speed.
[0042]
In the invention of claim 2, the communication between the base station and the mobile station is stabilized by selecting a plurality of base stations as relay destinations.
[0043]
In the invention of claim 3, an appropriate number of base stations can be selected as a relay destination according to the situation.
[0044]
In the invention of claim 4, for example, when the electric field strength of the first base station is very large in a certain slot and the electric field strength of the second and subsequent base stations is relatively very small, the second of the slot If a subsequent base station is selected as a relay destination, the efficiency is reduced, but by selecting a relay destination base station from a slot having a large number of base stations stored in a layer having a large electric field strength, As in the example, it is possible to avoid a decrease in efficiency due to selecting a relay destination base station from a slot with a very large difference in electric field strength between the first and second and subsequent, and select an appropriate base station with high accuracy. can do.
[0045]
In the invention of claim 5, for example, the order of the first and second base stations stored in the same slot of the data table is different from the order of the magnitude of the electric field intensity viewed from the mobile station, and the electric field intensity thereof. If the difference between the base stations is small, the mobile station may select the same base station repeatedly. In the above situation, the mobile station is prevented from selecting the same base station repeatedly in the above situation, thereby improving the accuracy of base station selection. be able to.
[0046]
In the invention of claim 6, when the communication between the base station and the mobile station is suspended, for example, when the base station pauses transmission for maintenance or the like, the electric field strength of the transmission radio wave from the base station decreases. Since the data table is updated when communication is interrupted, it is possible to improve the accuracy of base station selection as compared with the case where the data table created at the initial setting is continuously used.
[0047]
According to the seventh aspect of the present invention, it is possible to prevent duplication of another radio relay apparatus and a relay destination base station, thereby improving the accuracy of base station selection.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram of a wireless relay device used in first to fourth embodiments of the present invention.
FIG. 2 is a control channel timing chart for explaining the first embodiment of the present invention;
FIG. 3 is an explanatory diagram of the data table of the above.
FIG. 4 is an operation explanatory view of the above.
FIG. 5 is an operation explanatory view of the above.
6A and 6B are operation explanatory views of the same. FIG.
FIG. 7 is an explanatory diagram of a data table according to the second embodiment.
FIG. 8 is an operation explanatory view of the above.
FIG. 9 is an explanatory diagram showing an operation sequence according to the third embodiment.
10 is an operation explanatory diagram of the fourth embodiment. FIG.
FIG. 11 is an explanatory diagram of the data table in the above.
FIG. 12 is an explanatory diagram of the data table in the above.
FIG. 13 is an explanatory diagram of identification codes in the above.
FIG. 14 is an explanatory diagram of a duplication candidate list in the same as above.
FIG. 15 is an explanatory diagram showing the operation sequence of the above.
FIG. 16 is an explanatory diagram of the data table in the above.
FIG. 17 is an operation explanatory diagram of the above.
[Explanation of symbols]
A Mobile station
B1 ... Base station
C Wireless relay device
1 Antenna
2 Radio circuit block lock
3 Radio circuit control block
4 wireless communication units
5 CPU
6 memory

Claims (7)

Used in a wireless communication system that performs wireless packet communication between a mobile station and a base station using a plurality of time-division multiplexed slots, and relays each transmitted radio wave between the mobile station and the base station In the wireless relay device, referring to the data table, data table creating means for creating a data table representing the ranking of the base station using the radio field strength of the base station having a slot capable of communication at the initial setting after startup as an index, Base station selection means for selecting a relay destination base station that relays transmission data to and from a mobile station, and the base station selection means stores a plurality of base stations for the same slot in the data table. A base station having the second highest radio wave strength among the plurality of base stations in the slot is selected as a relay destination for the slot. Splicing device. The base station selection means selects a base station with the second highest electric field strength among the plurality of base stations in each slot when there are a plurality of slots in which the plurality of base stations are stored in the data table. 2. The wireless relay device according to claim 1, wherein the wireless relay device is selected as a relay destination. In the case where there is only one slot in which the plurality of base stations are stored in the data table, the base station selection unit selects a base station having the second highest electric field strength among the plurality of base stations in the slot. A relay destination for the slot is selected, and when there are a plurality of the slots, a base station having the second highest electric field strength among the plurality of base stations in each slot is selected as a relay destination for the slot. The wireless relay device according to claim 2. The data table creation means divides the electric field strength of the base station into a plurality of layers and stores the base station in each layer corresponding to the electric field strength of each base station at the time of initial setting, the base station selection means 4. The radio relay apparatus according to claim 3, wherein the relay destination base station is selected from slots having a large number of base stations stored in a hierarchy having a high electric field strength among a plurality of hierarchies of the data table. . The data table creation means deletes the plurality of base stations from the data table when a difference in electric field strength between the plurality of base stations stored in the same slot is smaller than a predetermined threshold value. The wireless relay device according to claim 4. The radio relay apparatus according to claim 1, wherein the data table creation unit updates the data table when communication between a base station and a mobile station is suspended. The data table creation means, comprising: an investigation means for investigating a base station selected as a relay destination by the other radio relay apparatus when another radio relay apparatus is stored as a base station in a slot in the data table 7. The base station selected by the other wireless relay device as a relay destination and the other wireless relay device are deleted from the data table by the investigation means. The wireless relay device described.

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