JP2008160823A - Spatial multiplexing slot allocation method, and adaptive array base station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spatial multiplexing slot allocation technique for improving user's convenience by surely accepting all connection requests without rejecting them, and performing a radio resource allocation in consideration of radio resources of an entire system. <P>SOLUTION: The adaptive array base station includes: a reception unit (111) for receiving connection requests transmitted from terminals; a transmission unit (114) for transmitting, to each of the terminals, a retry request requesting each of the terminals transmitting a connection request received by the reception unit to retry the connection request after the lapse of a predetermined time; a reservation control unit (122) which refers to an allocation control table (124) indicating the situation of radio resource allocation within the present station on the basis of the connection requests transmitted from the terminals, and reserves the radio resource allocation for each terminal within the predetermined time; and allocation control units (125, 113) for performing allocation control on the terminals using the reserved radio resource allocation after the reception unit receives the retry requests transmitted from the terminals after the lapse of the predetermined time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spatial multiplexing slot allocation method and an adaptive array base station.

In the conventional adaptive array base station spatial multiplexing system, a new request is rejected when the maximum number of spatial multiplexing is reached. In addition, when all calls are spatially multiplexed, an appropriate service grade and spatial multiplexing may not be maintained for each call. Therefore, a conventional technique (refer to Patent Document 1) that classifies according to call level, determines a call that is not spatially multiplexed, and provides an appropriate service grade has been proposed.
JP 2002-58061 A

  However, while the prior art described above makes it possible to provide an appropriate grade of service for a call, it still cannot accept a new call connection when the spatial multiplexing number reaches a maximum. A particular problem here is that even a call that requires high immediacy, such as VoIP (Voice Over IP), is rejected uniformly. FIG. 13 is an explanatory diagram of an adaptive array base station according to the prior art, FIG. 13 (a) is a configuration diagram, and FIG. 13 (b) shows processing of a connection request to the adaptive array base station according to the prior art. It is a flowchart. That is, as shown in these conventional diagrams, in the prior art, when a new connection request is received in a state where the maximum number of spatial multiplexing has been reached, connection of a new call is rejected regardless of whether it is a narrowband call or a wideband call. It was. As described above, in the conventional technology, when a new connection request is received in a state where the maximum spatial multiplexing number is reached, a new call connection is rejected. Therefore, unless the hardware is improved and the maximum spatial multiplexing number is increased, It was impossible to increase the number of connected users. In addition, because the allocation of spatial multiplexing slots was “first come first served”, even when there are many VoIP (narrowband call) users, new broadband calls cannot be connected, and the frequency utilization efficiency of the entire system is poor. There was a case.

  In other words, when considering the case where VoIP (narrowband call) is assigned to a subslot, the wireless processing unit that received the connection request (this In the example shown in the figure, the condition that the burst receiving unit, the slot allocation control unit, and the burst transmitting unit) do not reach the maximum spatial multiplexing number needs to be satisfied. In addition, since a new connection request is processed independently for each radio control unit, even if there is a margin in radio resources such as the number of spatial multiplexing of other radio control units (not shown) If the wireless processing unit that received the request has reached the maximum spatial multiplexing number, the connection request must be rejected.

  Therefore, the present applicant has developed a technique for accepting a new connection request using the subslot method when a new connection request is received when the maximum number of spatial multiplexing is reached (Japanese Patent Application No. 2006-264852). issue). FIG. 11 and FIG. 12 show a block diagram and a flowchart of an apparatus according to the technique developed by the present applicant. However, in the current adaptive array base station (apparatus), the radio processing unit is divided according to the combination of frequency band and time slot, and even with the above development technique developed by the applicant, a certain terminal makes a communication request. When the radio processing unit that controls and manages the transmitted carrier (frequency) and time slot reaches the maximum spatial multiplexing number and there is no radio resource that can be provided by the subslot method, the certain terminal requests a connection. Will be rejected and will be forced to retry.

  Therefore, the rejected terminal must retry the connection request with another carrier frequency, and this problem cannot be solved. On the other hand, even in a situation where the connection request is rejected, the radio resource may be released after a short time interval to accept the connection request. Even if the connection request is rejected, there is sufficient radio resources for the entire system, and it is sufficient to consider that there is the ability to allocate radio resources to the connection request source terminal not only in subslots but also in full slots. It is done. In other words, this problem is that a plurality of wireless processing units control and manage only the wireless resources in the range that they each handle, and thus the entire system cannot perform efficient and appropriate allocation processing of wireless resources. to cause.

  For example, when thinking about assigning subslots to new VoIP (narrowband calls), when there is a single subslot-assigned VoIP (narrowband) user who can be a subslot pair in another radio control unit However, if there is no VoIP (narrowband) user who can be paired in the radio control unit, it is necessary to allocate a new subslot, and subslot fragmentation occurs between radio processing units. The number of users connected simultaneously and the frequency utilization efficiency of the entire system were wasted. Thus, there is still room for improvement even with the subslot allocation scheme developed by the applicant.

  Furthermore, when the number of spatial multiplexing at a specific carrier frequency reaches the maximum, for example, when the terminal TM2 assigned with the spatial multiplexing slot at the specific carrier frequency moves, another spatial multiplexing at the same carrier frequency as the terminal TM2 The terminal TM1 to which the slot is assigned may be affected by the transmission wave radiated for the terminal TM2. That is, due to the influence of the transmission wave for the terminal TM2 transmitted by the adaptive array base station, the terminal TM2 shares the same carrier frequency (that is, using a different space (number) at the same timing as the terminal A at the same timing) Communication between the terminal TM1 (which is communicating) and the adaptive array base station may be subject to interference. In this case, the terminal TM2 similarly receives interference.

  Next, the mechanism of interference occurrence will be described. FIG. 14 is a conceptual diagram for explaining a typical situation of occurrence of interference. As shown in the figure, the base station BS communicates with two terminals TM1 and TM2. Terminals TM1 and TM2 use spatially multiplexed slots with the same carrier frequency and the same timing. The terminal TM1 uses VoIP as an application and is stationary. Terminal TM1 receives radio waves with beamform BF11 adjusted by the base station adaptive array antenna technology. On the other hand, the terminal TM2 is moving at a high speed (for example, 100 km / hr).

  At time t0, the terminal TM1 receives radio waves with the beamform BF1 adjusted by the base station adaptive array antenna technology, but no interference occurs at this point. At time t1, the terminal TM2 receives radio waves with the beamform BF2, but the beamform BF11 and the beamform BF2 directed to the terminal TM1 are directed in substantially the same direction, and both strongly interfere with each other. Interact with each other. At time t2, the terminal TM2 receives radio waves with the beamform BF3. At this time, the beamforms do not overlap with each other, so the terminal TM2 does not receive the interference of the beamform BF11 with respect to the terminal TM1.

  FIG. 15 is a graph showing temporal changes in transmission rates of the terminals TM1 and TM2 of FIG. As shown in the figure, it can be seen that the transmission rate is greatly reduced in both terminals at “around time t1” where the beam forms overlap. As described above, when a spatial multiplexing technique is used, when a certain terminal moves at a high speed, a situation may occur in which the transmission rate is significantly reduced due to interference.

  In such a situation, if there is a vacancy in another spatial multiplexing slot of another carrier frequency or another spatial multiplexing slot of the same frequency, the adaptive array base station uses the spatial multiplexing used by the terminal TM2. “Another free spatial multiplexing slot” that is not subject to slot interference can be reassigned to the terminal TM1. Thus, if an empty slot that is not subject to interference can be reassigned to terminal TM1, interference of terminal TM2 can be avoided. In this case, interference on the terminal TM2 side is also avoided.

  However, when there is no free slot that is not subject to interference (or when there is a shortage), for example, when the number of spatial multiplexing reaches the maximum at all carrier frequencies, the adaptive array base station has no space for terminals TM1 or TM2. Multiple slot reassignment cannot be performed.

  Therefore, the present invention improves not only narrow-band calls such as VoIP but also all connection requests without refusing and assigning radio resources in consideration of the radio resources of the entire system, improving user convenience. An object of the present invention is to provide a spatial multiplexing slot allocation method and an adaptive array base station. It is another object of the present invention to provide a spatial multiplexing slot allocation method and adaptive array base station that further suppresses interference to each terminal while performing radio resource allocation considering radio resources of the entire system.

In order to solve the above-described problems, the method according to the first invention is as follows.
An adaptive array (antenna) base station spatial multiplexing slot allocation method for communicating with a plurality of terminals,
(Adaptive array base station receives each connection request transmitted from each terminal, and)
Transmitting a retry request to each terminal that has transmitted the connection request to request that the connection request be retried after a predetermined time has elapsed (after m frames);
(The step of managing / updating the allocation management table indicating the status of radio resource allocation in the own station)
Each connection request transmitted from each terminal (for example, one connection request and another connection request within a predetermined time from the time of the connection request of the terminal, or a connection request of the terminal Based on other connection requests made before the point in time, such as connection requests for which reservation / allocation of radio resource allocation has not yet been completed, the status of radio resource allocation within the local station (for example, current radio resource allocation) Reserving radio resource allocation for each terminal within the predetermined time period with reference to an allocation management table indicating a situation of (2), and a radio resource allocation change within a predetermined time period,
Receiving a retry request transmitted from each of the terminals after a predetermined period of time;
Performing allocation control on each terminal using the reserved radio resource allocation (after receiving the retry request);
It is a method including.

The spatial multiplexing slot allocation method according to the second invention
The allocation management table has slot system information indicating whether each radio resource allocation is based on a subslot system (whether it is based on a full slot system),
The spatial multiplex slot allocation method includes:
A first determination step of determining whether each connection request transmitted from each terminal is a narrowband call (whether it is a wideband call);
The step of booking comprises:
With reference to the slot method information stored in the allocation management table, the first determination step is performed for a single subslot that does not form a subslot pair among existing radio resource allocations by the subslot method. A terminal having a connection request determined to be a narrowband call at 1 reserves radio resource allocation so as to form a sub-slot pair with the single sub-slot.
It is characterized by that.

The spatial multiplex slot allocation method according to the third invention
A first determination step of determining whether each connection request transmitted from each terminal is a narrowband call (whether it is a wideband call);
The step of booking comprises:
By two terminal calls determined to be narrowband calls in the first determination step, two subslot pairs (two narrowband call terminals newly requesting connection are assigned the same "one time slot" Reserving radio resource allocation in the sub-slot method so as to form a slot usage relationship that is shared between calls)
It is characterized by that.
That is, when there is no single subslot in the already assigned subslot in the own station, it is preferable to form a subslot pair with new calls before assignment.

  Further, as a spatial multiplexing slot allocation method, the connection request from the terminal includes contract type information of the terminal, and whether or not the connection request from the terminal is a narrowband call (or a broadband call) ) Can be determined based on the contract type information of the terminal, and the processing load can be reduced since the VoIP (narrowband call) bit embedded in the RA burst is not read.

  For example, as a spatial multiplexing slot allocation method, when each connection request from each terminal is not a narrowband call (that is, a broadband call), full slot allocation control is performed at any carrier frequency. The other terminal of the narrowband call is changed to the sub-slot allocation control (that is, the full slot as the allocated resource is once released and reassigned by the sub-slot method), and the full slot scheme is assigned to the terminal. It can be configured to perform allocation control (allocation of released full slots).

The spatial multiplex slot allocation method according to the fourth invention
The allocation management table has slot system information indicating whether each radio resource allocation is based on a sub-slot system,
The spatial multiplex slot allocation method includes:
Determining whether the moving speed of each terminal exceeds a predetermined value;
The step of booking comprises:
With reference to the slot method information stored in the allocation management table, in the determination step for a single subslot that does not form a subslot pair among existing radio resource allocations by the subslot method. A terminal having a connection request determined to have a moving speed exceeding a predetermined value reserves radio resource allocation so as to form a subslot pair with the single subslot.
It is characterized by that.

  Here, the predetermined value is a threshold value used as a reference for determining whether or not the terminal is moving at a high speed. If the predetermined value is exceeded, it can be determined that the terminal is moving at a high speed. On the other hand, if it is less than or equal to this predetermined value, it can be determined that the terminal is moving at low speed or is stationary. As for the moving speed of the terminal, if the wireless communication system has moving speed information, the moving speed information of the system can be used directly. Alternatively, the moving speed may be estimated from phase changes in a plurality of known signals included in a wireless communication frame. Furthermore, the moving speed may be estimated using a fading speed (corresponding to the moving speed) estimation method.

A spatial multiplexing slot allocation method according to the fifth invention is
Determining whether the moving speed of each terminal exceeds a predetermined value;
The step of booking comprises:
Reserving radio resource allocation in a subslot manner so as to form a subslot pair by two terminal calls determined to have a moving speed exceeding a predetermined value in the determining step;
It is characterized by that.

Also, the spatial multiplex slot allocation method according to the sixth invention is:
As a result of the determination in the first determination step, when there is a connection request terminal that is determined not to be a narrowband call (that is, a broadband call), the moving speed of the terminal that is determined not to be the narrowband call is: A second determination step of determining whether or not the predetermined value is exceeded;
The step of booking comprises:
With reference to the slot method information stored in the allocation management table, the first determination step is performed for a single subslot that does not form a subslot pair among existing radio resource allocations by the subslot method. The connection requesting terminal, which is determined to be a narrow-band call at step 2 or determined to have a moving speed exceeding a predetermined value in the second determination step, forms a subslot pair with the single subslot. To reserve radio resource assignments,
It is characterized by that.

Also, the spatial multiplex slot allocation method according to the seventh invention is:
As a result of the determination in the first determination step, when there is a connection request terminal that is determined not to be a narrowband call (that is, a broadband call), the moving speed of the terminal that is determined not to be the narrowband call is: A second determination step of determining whether or not the predetermined value is exceeded;
The step of booking comprises:
Reserving radio resource allocation in a subslot manner so as to form a subslot pair by two terminal calls determined to have a moving speed exceeding a predetermined value in the determining step;
It is characterized by that.

  As described above, the solution of the present invention has been described as a method. However, the present invention can be realized as a device, a program, and a storage medium storing the program substantially corresponding to these, and the scope of the present invention. It should be understood that these are also included.

For example, a base station (apparatus) according to the eighth aspect of the present invention that realizes the present invention as an apparatus is:
An adaptive array base station (such as a wireless communication device) that communicates with a plurality of terminals using a spatial multiplexing slot allocation method,
A receiving unit (such as a circuit) that receives each connection request transmitted from each terminal;
A retry request is sent to each terminal that requests the terminal that has transmitted the connection request received by the receiving unit to retry the connection request after a predetermined time has elapsed (after m frames). A transmitter (circuit, etc.)
Each connection request transmitted from each terminal (for example, one connection request and another connection request within a predetermined time from the time of the connection request of the terminal, or a connection request of the terminal Based on other connection requests made before the point in time, such as connection requests for which reservation / allocation of radio resource allocation has not been completed yet, the status of radio resource allocation within the own station (for example, each frequency band and slot) The radio resource allocation for each terminal is reserved within the predetermined time with reference to an allocation management table indicating the current radio resource allocation status for each status, and further, a change in radio resource allocation within a predetermined time) Reservation management department (circuit etc.)
An allocation control unit (circuit) that performs allocation control on each terminal using the reserved radio resource allocation after receiving a retry request transmitted from each terminal after elapse of the predetermined time by the receiving unit etc,
Have

An adaptive array base station according to the ninth invention is
A plurality of radio processing units (provided for each combination of frequency band and time slot) having the receiving unit and the transmitting unit;
A central control unit having the reservation management unit and the allocation control unit;
It is characterized by that.

An adaptive array base station according to the tenth invention is
The allocation management table has slot system information indicating whether each radio resource allocation is based on a subslot system (whether it is based on a full slot system),
The adaptive array base station is
A bandwidth determination unit (such as a circuit) that determines whether each connection request transmitted from each terminal is a narrowband call (whether it is a wideband call);
The reservation management unit
With reference to the slot method information stored in the allocation management table, the band determination unit performs the determination on a single subslot that does not form a subslot pair in the existing radio resource allocation by the subslot method. A terminal having a connection request determined to be a narrowband call reserves a radio resource allocation so as to form a subslot pair with the single subslot.
It is characterized by that.

An adaptive array base station according to the eleventh invention is
A bandwidth determination unit that determines whether each connection request transmitted from each terminal is a narrowband call (whether it is a wideband call);
The reservation management unit
Sub-slot pairs (slots in which two narrowband call terminals newly requesting connection share the same “one slot” by two terminal calls determined to be narrowband calls by the band determination unit. Reserving radio resource allocation in a sub-slot method to form a usage relationship)
It is characterized by that.

An adaptive array base station according to the twelfth invention is
The allocation management table has slot system information indicating whether each radio resource allocation is based on a sub-slot system,
The adaptive array base station is
A moving speed determination unit that determines whether the moving speed of each terminal exceeds a predetermined value;
The reservation management unit
With reference to the slot method information stored in the allocation management table, the moving speed determination unit for the single subslot that does not form a subslot pair in the existing radio resource allocation by the subslot method The terminal determined to have a moving speed exceeding a predetermined value by the above reserves a radio resource allocation so as to form the single subslot and the subslot pair.
It is characterized by that.

An adaptive array base station according to the thirteenth invention is
A moving speed determination unit that determines whether the moving speed of each terminal exceeds a predetermined value;
The reservation management unit
Reserving radio resource allocation by a subslot method so as to form a subslot pair by two calls of a terminal determined to have a moving speed exceeding a predetermined value by the moving speed determination unit;
It is characterized by that.

In addition, the adaptive array base station
The connection request from each terminal includes contract type information of the terminal,
The determination unit
Determining whether the connection request from the terminal is a narrowband call (or a broadband call) based on the contract type information of the terminal;
It can be constituted as follows.

For example, an adaptive array base station
The allocation control unit
If the connection request from the terminal is not a narrowband call (that is, a broadband call), another terminal of the narrowband call that performs full slot allocation control at any carrier frequency is assigned to the subslot. Change to the allocation control of the system (that is, release the full slot, which is the allocated resource, and reallocate it by the subslot system), and the terminal in the full slot system (allocate the released full slot) Perform allocation control,
It can be constituted as follows.

  According to the present invention, regarding spatial multiplex slot allocation of an adaptive array base station, not only connection requests for narrowband calls such as VoIP but also all connection requests are temporarily suspended to ensure allocation control time, and this allocation control During the time, it is possible to perform allocation control in consideration of radio resources to each terminal throughout the system. For example, by efficiently generating a combination of narrowband calls from among the entire radio resources and assigning subslots, the number of simultaneously connected users and frequency utilization efficiency of the entire system can be greatly improved. Therefore, stable communication is possible without rejecting the connection request.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an adaptive array base station according to Embodiment 1 of the present invention. As shown in the figure, the adaptive array base station 100 includes first to first combinations provided for each combination of a carrier frequency band number and a slot number (for example, the number of combinations n = the number of frequency bands 8 × the number of slots 3 = 24). A plurality of wireless processing units 110 to 110n up to the nth are provided. The first to n-th radio processing units 110 to 110n are burst reception units 111 to 111n that receive RA bursts of connection requests, RA burst reception number management units 112 to 112n that store and manage the number of RA burst receptions, and wireless Burst reservation units 113 to 113n for managing resource allocation reservations and burst transmission units 114 to 114n are provided. Each of the wireless processing units 110 to 110n further includes a maximum spatial multiplexing number determination unit (not shown) that manages the maximum spatial multiplexing number and determines whether or not the maximum spatial multiplexing number has been reached. As the processing capability of the CPU improves, a configuration of “number of wireless processing units = number of frequency bands” is also possible.

  The adaptive array base station 100 further includes a central control unit 120 that controls n radio processing units 110 to 110n and an adaptive array antenna ANT composed of a plurality of antennas. The central control unit 120 includes a VoIP (narrowband call) determination unit 121 that determines whether the call is a VoIP (narrowband call), a radio resource reservation management unit 122 that manages radio resource reservation / allocation status, and the like. And a radio allocation control unit 125 that controls the reservation, a subslot management unit 123, and an allocation management table 124.

  Next, the data flow is shown. First, the first RA burst (connection request) is transmitted from the terminal side to the base station side, and the burst receiving unit 111 corresponding to the carrier frequency used by the RA burst, in this example, the first radio processing unit It is received by the burst receiver 111 in 110. Next, the burst reception number management unit 112 determines whether the RA burst (connection request) from the terminal is the first time or the second time. When the RA burst (connection request) from the terminal is the first time, it is notified to the burst transmission unit 114, and an AA burst (pending and a response message requesting to retry after m frames) is sent to the terminal. And a VoIP (narrowband call) determination unit 121 reads a VoIP (narrowband call) bit embedded in advance in the RA burst. Next, the radio resource reservation management unit 122 refers to the allocation management table 124 to check the current radio resource availability. If there is no free radio resource, the system waits for an allocation control time of m frames. If there is no free radio resource even after waiting for “allocation control time of m frames”, the wireless allocation control unit 125 is notified of “connection rejection”. When an empty radio resource is generated within the allocation control time, the radio allocation control unit 125 is notified that the radio resource has been reserved for allocation. The allocation reservation status is immediately transferred from the radio allocation control unit 125 to the radio processing unit from which the terminal has transmitted the RA burst. If there are free radio resources and VoIP (narrowband call), the sub-slot management unit 123 is inquired of the sub-slot usage status, the radio resource is determined, and the radio resource reservation management unit 122 is notified. If there are free resources and non-VoIP (ie, broadband call), radio resources are determined (reserved), and the radio allocation control unit 125 is notified of “full slot allocation (reservation)”. Next, the allocation reservation result of the radio allocation control unit 125 is notified to the burst reservation units 113 to 113n of each radio processing unit. The subslot management unit 123 may be included in the radio resource reservation management unit 122.

（FS:フルスロット、SSのみ:単独サブスロット、(SS,SS):サブスロット対、空欄：完全な空きスロット）

(FS: full slot, SS only: single subslot, (SS, SS): subslot pair, blank: completely empty slot)

  As an example, Table 1 shows an allocation management table. This allocation management table is for the spatial multiplexing number 1. When the spatial multiplexing number is 3, there are two other similar allocation management tables. Further, in this case, the allocation reservation rule is that a narrowband call is assigned by the sub-slot method in order from the one with the largest frequency band number (ie, frequency band # 8) to the smaller number, and conversely, the one with the smaller frequency band number ( That is, broadband calls are allocated in order from the frequency band # 1) to the larger numbers in the “full slot system”. For example, when one VoIP (narrowband call) requests connection, since there is a single subslot in slot # 2 of frequency band # 7, the subslot is paired with this existing single subslot. Make an allocation reservation. In this way, when a sub-slot pair is formed by combining a narrowband call and an existing single subslot sequentially, the single subslot is consumed and the use efficiency of the frequency band is increased. Eventually, when the single subslot in Table 1 disappears, a new single subslot is allocated by using half of one new slot.

  FIG. 2 is a flowchart showing an allocation algorithm in the radio resource reservation manager 122 according to the first embodiment of the present invention. As shown in the figure, the RA burst (connection request) transmitted from the terminal is received in step S10. In step S11, an AA burst (pending and a message requesting to retry after elapse of m frames) is transmitted to the terminal in order to secure radio resource allocation control time. Next, in step S12, it is determined whether or not the connection request (call) from the terminal is VoIP (narrow band). If it is determined in step S12 that the connection request (call) is VoIP (narrow band), it is determined whether there is an available radio resource in the system (step S13). If it is determined that there are free radio resources in the system, the process proceeds to step S14, and whether there is no free subslot (ie, there is no single subslot that does not constitute a subslot pair in one slot). judge. If the determination condition of step S14 is satisfied, that is, if there is no empty subslot, a new subslot is reserved for allocation to the terminal (step S15).

  If it is determined in step S12 that the connection request (call) is not VoIP (narrow band), the process proceeds to step S16, and it is determined whether or not there is a free radio resource in the system. If it is determined in step S16 that there are free radio resources in the system, the process proceeds to step S17, and a full slot allocation reservation is made for the terminal. If it is determined in step S16 and step S13 that there are no free radio resources in the system, the process proceeds to step S18, and an AA burst indicating connection refusal is reserved in the terminal. If it is determined in step S14 that there is an empty subslot, the process proceeds to step S19, and the terminal is reserved for subslot allocation so as to create a subslot pair with another existing single subslot.

  After Steps S15 and S17-19 are completed, the process proceeds to Step S20, and after the first connection request, an RA burst, which is a retry of the connection request from the terminal transmitted after m frames have elapsed, is received. . That is, when the RA burst (connection request) from the terminal is the second time, the burst reception number management unit 112 activates the burst reservation unit 113 and transfers the reserved AA burst data to the burst transmission unit 114. AA burst (one of “full slot allocation”, “subslot allocation that forms a pair with existing single subslot”, “new subslot allocation”, “allocation rejection”) is transmitted to the terminal. Is done. In response to the retry RA burst, in step S21, an AA burst indicating the reservation result is transmitted to the terminal, and the process is terminated. Here, the “full slot” means a normal slot configuration. On the other hand, the “subslot” is a slot configuration in which the “full slot” is divided into two by time share for one set (two) users (calls) that require only a narrow bandwidth such as VoIP. That is. As shown in FIG. 4, the time sharing method includes (1) a method in which even frames and odd frames are alternately used by two users, and (2) a method in which slots are divided into a first half and a second half and used by two users. (This will be described in detail with reference to FIG. 4).

  FIG. 3 is a sequence diagram illustrating an operation between the terminal and the base station. As shown in the figure, messages are exchanged between the terminal UT, the radio processing unit A and the radio processing unit B constituting the base station BS, and the central control unit CU responsible for overall control of these processing units and the base station. is there. The terminal UT transmits an RA burst, which is the first connection request, to the radio processing unit A at the time of N frames. The wireless processing unit A once accepts this and transmits an AA burst (pending and requesting retry after elapse of m frames) to the terminal UT as a response. The radio processing unit A transmits a radio resource allocation request to the terminal UT to the central control unit CU. The central control unit CU determines radio resource allocation (reservation) before reaching the [N + m−1] frame. In this example, the radio processing unit B determines the radio resource to be processed. Then, the central control unit CU transmits the radio resource allocation result (AA burst reservation) to the radio processing unit A. The central control unit CU also transmits the radio resource allocation result (TCH burst reservation) to the radio processing unit B that is the radio resource allocation destination.

  After waiting for m frames (that is, at the time of [N + m] frame), the terminal UT transmits a retry connection request to the same wireless processing unit A that transmitted the first connection request. The radio processing unit A transmits the AA burst (allocation result including the carrier frequency of the radio processing unit B) received and stored from the central control unit CU to the terminal UT. After this (after [N + m + 1] frame), a TCH (traffic channel) is established between the terminal UT and the radio processing unit B, and communication is started. In this example, the central control unit CU allocated the radio resource of the radio processing unit B instead of the radio processing unit A that transmitted the first connection request, but depending on the status of the radio resource, Note that it is possible to allocate radio resources. Further, as can be understood from this sequence diagram, since the central control unit CU can secure an allocation control time of “m frames”, a change in radio resources within the allocation control time and an allocation reservation have not yet been determined. Considering the status of all radio resources in the own station including the connection request, it becomes possible to allocate radio resources flexibly and efficiently. For example, an algorithm that preferentially assigns to a radio processing unit that does not consume much radio resources may be adopted. When a narrowband call requests connection, a sub-slot is combined with an existing single sub-slot. You may prioritize the configuration of slot pairs and suppress the occurrence of single subslots as much as possible. Furthermore, among the new connection requests queued within the allocation control time, subslots can be used between narrowband calls. Priority may be given to configuring pairs (ie, sharing one slot for two calls).

  The allocation control time of “m frame” is “connection delay time” for the terminal side. For example, in the prior art, when the user is busy, such as when a large number of connection requests are made, the carrier frequency or the like is changed, and connection requests are retried repeatedly to connect. On the other hand, according to the technique of the present invention, radio resources can be almost certainly secured by two connection requests. Therefore, in the present invention, useless frequency band consumption is suppressed by the connection request (that is, unnecessary retry is suppressed). Thus, there is an advantage that the average delay time until the connection is completed can be shortened as compared with the prior art.

  FIG. 4 is a timing chart for explaining an example of the subslot system according to the present invention. FIG. 4A shows an original time slot (full slot) of the full slot system, where the upper Tx when viewed from the base station is the time slots # 1 to # 3 on the transmission side, and the lower Rx Are time slots # 1 to # 3 on the receiving side, which are asymmetric time intervals.

  FIG. 4B shows a state in which subslots are formed by alternately allocating slots according to even frames and odd frames. For user 1, slot # 1 of frame F1 which is an odd frame is assigned as subslot SS11, and slot # 1 of frame F3 is assigned as subslot SS12. Similarly, for user 2, slot # 1 of frame F2, which is an even frame, is assigned as subslot SS21, and slot # 1 of frame F4 is assigned as subslot SS22.

  FIG. 4C shows a method of dividing one time slot into a first half part and a second half part to form subslots. User 3 is assigned the first half of slot # 1 of each frame F1 to F4 as subslots SS31 to SS34. On the other hand, the second half of slot # 1 of each frame F1 to F4 is assigned to user 4 as subslots SS41 to SS44. In addition, if the slot on the receiving side, which is half the slot length compared to the slot on the transmitting side, is left as a full slot and any user's slot is temporarily shared, the communication quality / The degradation of the communication area can be kept to a minimum.

  FIG. 5 is a timing chart for explaining an example of a subslot system according to the present invention, in which a user of a narrowband call that previously occupied a full slot is subslotted, and a full slot is given to a user of a new wideband call. Show the case. FIG. 5A shows an original time slot (full slot) of the full slot system similar to FIG.

  FIG. 5B shows that in slot # 1 of frame F1, full slot FS51 is allocated to broadband call user 5, full slot FS61 is allocated to narrowband call user 6, and full slot FS71 is allocated to narrowband call user 7. Yes. Here, consider a case where the user 8 of the broadband call attempts a connection request. The base station sub-slots user 6 and user 7 of the narrowband call to form a pair, so that in some field of the header part of full slots FS61 and FS71, subslots are made from the next frame F2 and the first half of slot # 1. And the fact that switching to the latter half is transmitted to the users 6 and 7, and the slot occupied by the user 7 is released. Then, subslots SS61 and SS71 are allocated to users 6 and 7 in the next frame F2. Subslots SS62 and SS72 are allocated to users 6 and 7 in the subsequent frame F3. From the next frame F2, the full slot FS81 is assigned to the user 8 of the broadband call, and the full slot FS82 is also assigned to the subsequent frame F3. In this way, it is possible to rescue and accept a user of a broadband call such as the user 8 that has been rejected after reaching the maximum multiplexing number. On the other hand, the user 5 of the broadband call continues to obtain FS52 and FS53 as full slots. In the embodiment of FIGS. 4 and 5, the sub-slot format in which one slot is divided into two has been described. However, this is merely an example, and the present invention can be realized with three or more sub-slots. Please note that.

  In addition, in the AA burst other than the connection rejection, information indicating the radio resource of the assignment destination is embedded, and the terminal side refers to this information to establish a communication channel with the base station.

  FIG. 6 is a block diagram showing a configuration of an adaptive array base station according to the second embodiment of the present invention. The components of the adaptive array base station 100A are substantially the same as those of the adaptive array base station 100 of FIG. Description of these same components will be omitted, and only differences will be described. As shown in FIG. 6, in the second embodiment, in addition to the configuration of the first embodiment, a high-speed movement determination unit 126 is provided in the central control unit 120A. The high-speed movement determination unit 126 determines whether or not the movement speed of the terminal exceeds a predetermined movement speed. The predetermined moving speed is read from a memory (not shown). Alternatively, the predetermined moving speed may be set / calculated according to the current radio wave environment (interference state) and radio resources.

  The high-speed movement determination unit 126 acquires the movement speed of a terminal managed by the adaptive array base station 100A, typically a terminal that has newly requested a connection. The moving speed is read from a “high-speed moving bit” that is embedded in advance in the RA burst and indicates information on the moving speed acquired by the terminal itself. Alternatively, adaptive array base station 100A may estimate the moving speed of the terminal from phase changes in a plurality of known signals included in the frame. Furthermore, the moving speed of the terminal may be estimated using an estimation method based on fading speed (which changes corresponding to these moving speeds).

  This movement speed is acquired not only when an RA burst is received but also when another burst is received. At approximately the same time, the VoIP determination unit 121 reads VoIP (narrowband call) bits embedded in advance in the RA burst. Alternatively, when a terminal is registered (registered), each terminal is assigned a terminal identification number ID. At the time of this registration, the base station has already decided whether the call is a broadband call or a narrowband call. The band can be specified from. In such a case, it is not necessary to embed a VoIP (narrowband call) bit in the RA burst. Based on the “terminal identification number ID” included in most burst signals, the base station It is possible to easily determine whether it is (narrowband call) or not (non-VoIP). In the second embodiment, in addition to the determination result of VoIP (narrowband call) and non-VoIP, the determination result of whether or not the user is moving at high speed is used in the radio resource reservation management unit 122 or the like.

  FIG. 7 is a flowchart illustrating an allocation algorithm in the radio resource reservation management unit according to the second embodiment of the present invention. The processing steps of the second embodiment include processing steps similar to those of the first embodiment, and only differences from the processing steps of the first embodiment will be described. In Example 2, step S30 performed when the condition of step S12 is not satisfied is newly provided. As shown in the figure, in step S30, it is determined based on the determination result of the high-speed movement determination unit 126 whether or not the call is high-speed movement. If it is determined that the terminal is moving at high speed, the process proceeds to step S13. If it is determined that the terminal is not moving at high speed, the process proceeds to step S16. The processes after steps S13 and S16 are the same as those in the first embodiment. In this way, when a terminal of a non-VoIP call (that is, a broadband call) is moving at high speed, the process can proceed to the subslot allocation process after step S13 to obtain a subslot allocation, that is, an opportunity for connection. It becomes possible. In addition, since the terminal is subslotted while ensuring the connection of the terminal moving at high speed, interference with other spatially multiplexed terminals can be reduced using the same existing frequency. Is possible.

  FIG. 8 is a flowchart illustrating an allocation algorithm in the radio resource reservation management unit according to the third embodiment of the present invention. In this embodiment, the allocation of an existing full slot is changed to a subslot, and this subslot and the subslot of a new call form a “subslot pair”. As shown in the figure, after the base station receives the RA burst (connection request) from the terminal in step T10, the carrier frequency of the AA burst (full slot allocation) transmitted from the terminal reaches the maximum spatial multiplexing number. It is determined whether or not it has been completed (step T11). If the maximum spatial multiplexing number has not been reached, an AA burst (full slot allocation) is transmitted to the terminal that has transmitted the RA burst (connection request) in step T12.

  If it is determined in step T11 that the carrier frequency has reached the maximum spatial multiplexing number, it is determined in step T13 whether the call is a VoIP (narrowband call). This determination may be made by notifying the terminal contract status (type of narrowband contract, broadband contract, etc.) at the time of registration of the terminal that transmitted the call, or including a band designation in the connection request call itself. The determination is made based on these pieces of information. If it is determined in step T13 that the call is not VoIP (narrowband call), that is, it is a wideband call, the moving speed information of the terminal in the call is acquired, and the predetermined moving speed is exceeded. It is determined whether or not (step T14). If it is determined in step T14 that the moving speed of the terminal is not the predetermined moving speed, that is, the terminal moves at a low speed or does not move, the QoS (communication quality) of the call is acquired and the communication exceeds the predetermined QoS. Is determined (step T15). When it is determined in step T15 that the QoS of the terminal does not exceed the predetermined QoS, the process proceeds to step T17, where the base station transmits an AA burst (connection rejection) to the terminal and ends the process. In this case, the rejected terminal needs to shift to another carrier frequency and retry the RA burst (connection request) again.

  On the other hand, when any one of the determination conditions of Step T13, Step T14, and Step T15 is satisfied, the process proceeds to Step T16. In step T16, the moving speed information of a terminal to which a full slot has already been assigned by the full slot method at the carrier frequency is acquired. This movement speed information may be estimated from the signal quality acquired at the time of communication after the full slot allocation for each terminal by the base station, or the terminal acquires information regarding its own movement state, and this acquisition Information may be acquired later by the base station from the terminal. Then, in step T18, it is determined whether or not the moving speed information of the terminal to which a full slot has already been allocated exceeds a predetermined moving speed.

  If it is determined in step T18 that the moving speed information exceeds the predetermined moving speed, the allocation of the terminal is switched from the full slot to the subslot in step T19. Specifically, in order to make a full slot occupied by a terminal moving at a speed exceeding a predetermined moving speed into a subslot, a subslot is made from the next frame in some field of the header part of the full slot. Then, the fact that only the first half or the second half of the same slot to which the full slot is assigned is assigned as a subslot is transmitted to the terminal, and the full slot occupied by the terminal is once released. Then, in the next frame, a subslot is assigned to the terminal.

  After changing the allocation of the existing full slot to a subslot in the above step, a new terminal that has transmitted (one requested to connect) an RA burst to “one subslot” generated by subslotting in step T20 AA burst (subslot allocation) is transmitted to the end of the process. The existing full slot assignment is changed to a subslot, and this subslot and the new call subslot form a "subslot pair". If the condition of step T18 is not satisfied, the process proceeds to step T17, where an AA burst (connection rejection) is transmitted to the terminal, and the process ends.

  FIG. 9 is a flowchart illustrating an allocation algorithm in the radio resource reservation management unit according to the fourth embodiment of the present invention. In this embodiment, full slots that are already allocated to two terminals are subslotted to form subslot pairs, and new slots that have been requested to be connected are allocated full slots that are freed by subslotting. is there. The present embodiment is the same as the embodiment of FIG. 8 except for steps P30 to P34, and only differences from FIG. 8 will be described. As shown in FIG. 9, when it is determined in step P18 that the moving speed information exceeds the predetermined moving speed, the terminal that is moving beyond the predetermined moving speed and occupies the full slot It is determined whether or not there is one set (that is, two in total). When the determination condition is satisfied in Step P30 (when there is one set of terminals that move beyond the predetermined moving speed and occupy the full slot in the unified spatial multiplexing), each full slot to be paired is selected. Switching to each subslot forms a subslot pair (step P31, P32), and proceeds to step P33. In Step P33, it is determined whether or not there is a full slot available. When the process proceeds to step P33 via steps P31 and P32, as a result of switching the full slot to the subslot, naturally, an “empty full slot” is generated. Therefore, the process proceeds to step P34, where the connection request is made to the terminal. An AA burst (full slot allocation) is transmitted, and the process ends.

  As described above, according to the embodiment described above, it is possible to accept a connection request without being rejected even for a broadband call after reaching the maximum spatial multiplexing number. That is, it is not necessary for the terminal to shift to another carrier frequency, transmit an RA burst (connection request) again, and retry the connection, and can smoothly start communication. If the determination condition in step P18 is not satisfied, it is determined whether or not there is one set of VoIP (narrowband call) calls that have already been assigned full slots without ending the process. When the condition is satisfied, the two calls may be subslotted in the same manner as the subslotting performed for the terminal call exceeding the predetermined moving speed described above. As a result, it is possible to expect a further increase in the number of simultaneously connected users and an improvement in frequency utilization efficiency.

  FIG. 10 is a timing chart for explaining an example of the subslot system according to the present invention. FIG. 10 is the same as FIG. As shown in FIG. 10B, the user 9 to which the full slot FS91 moving at high speed is assigned as a subslot, and an “empty subslot” is generated for the user 10. The user 9 is assigned subslots SS91 and SS92 in the subsequent frames. On the other hand, to the user 10 moving at high speed, the sub slots vacated by switching the full slot of the user 9 to the sub slots are assigned as sub slots SS01 and SS02 from the next frame. In this way, when there is no single subslot that should form a subslot pair, subslot pairs are created for new and existing calls by subslotting the full slot of the existing call. It becomes possible to use the frequency efficiently.

  FIG. 16 is a graph showing temporal changes in transmission rates of the terminals TM1 and TM2 that are subslotted by applying the present invention. As shown in the figure, the decrease in the transmission rate in the “near time t1” where the beam forms overlap is slight. In this way, by using subslots, when using a spatial multiplexing technique, it is possible to significantly suppress interference that occurs when a certain terminal moves at a high speed compared to the conventional case (FIG. 15). Become. Therefore, as shown in the figure, it is possible to obtain a sufficient transmission rate at both terminals. In particular, when the present invention is applied to an adaptive modulation scheme, the “apparent band” is reduced by subslotting, but radio wave interference is suppressed, so a higher-rate modulation scheme can be selected. It becomes possible. Therefore, a sufficient throughput can be obtained even if subslots are used.

  The upper table is a transmission rate transition table simulating the transmission rate (throughput) before and after applying the present invention. In the prior art, the period from time 10 to time 15 in which the background is shaded is a time zone in which the transmission rates of both terminals are greatly reduced due to interference. As shown in this table, by applying the present invention, not only the terminal TM2 to which the present invention is applied but also the radio wave interference of the terminal TM1 existing in the same cell can be significantly reduced. Can be observed from Table 2.

  As described above, according to the present invention, a spatial multiplex slot allocation algorithm using a technique (referred to as “Extended RACH”) for temporarily determining a resource usage status of the entire system by pending a new connection request is adopted. Thus, subslots can be efficiently allocated to new connection requests, particularly VoIP (narrowband calls). Also, for normal calls other than VoIP (narrowband calls), VoIP calls are efficiently sub-slotted to form sub-slot pairs, which increases the number of available resources, reducing the probability of connection rejection, The total number of simultaneously connected users and frequency utilization efficiency can be greatly improved.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each unit, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means, steps, etc. can be combined or divided into one. It is. For example, the radio processing unit, the central control unit, and these components (such as a radio resource reservation management unit) may be configured by hardware (circuit), but a combination of a processor such as an MPU or DSP and a software module, Or you may comprise by the combination of a hardware and a software module.

It is a block diagram which shows the structure of the adaptive array base station by Example 1 of this invention. It is a flowchart which shows the allocation algorithm in the radio | wireless resource reservation management part 122 by Example 1 of this invention. It is a sequence diagram which shows operation between a terminal and a base station. It is a timing chart explaining an example of the subslot system by this invention. It is a timing chart explaining an example of the subslot system by this invention. It is a block diagram which shows the structure of the adaptive array base station by Example 2 of this invention. It is a flowchart which shows the allocation algorithm in the radio | wireless resource reservation management part by Example 2 of this invention. It is a flowchart which shows the allocation algorithm in the radio | wireless resource reservation management part by Example 3 of this invention. It is a flowchart which shows the allocation algorithm in the radio | wireless resource reservation management part by Example 4 of this invention. It is a timing chart explaining an example of the subslot system by this invention. 1 is a block diagram of an apparatus according to a technique developed by the present applicant. 2 is a flowchart of an apparatus according to a technique developed by the applicant. It is explanatory drawing of the adaptive array base station by a prior art. It is a conceptual diagram explaining the typical situation of interference generation. It is a graph which shows the time change of the transmission rate of terminal TM1, TM2 of FIG. It is a graph which shows the time change of the transmission rate of the terminals TM1 and TM2 which are subslotted by applying the present invention.

Explanation of symbols

100 Adaptive array base station 110-110n Radio processing unit 111-111n Burst receiving unit 112-112n Burst reception frequency management unit 113-113n Burst reservation unit 114-114n Burst transmission unit 120 Central control unit 121 VoIP determination unit 122 Radio resource reservation management Unit 123 subslot management unit 124 allocation management table 125 radio allocation control unit 100A adaptive array base station 120A central control unit 126 high-speed movement determination unit ANT adaptive array antenna F1-F4 frame FS51-FS53 full slot FS61 full slot FS71 full slot FS81, FS82 full slot FS91 full slot SS11, SS12 subslot SS21, SS22 subslot SS31-SS34 subslot SS41-SS 44 subslot SS61, SS62 subslot SS71, SS72 subslot SS91, SS92 subslot SS01, SS02 subslot

Claims (13)

An adaptive array base station spatial multiplexing slot assignment method for communicating with a plurality of terminals,
Sending a retry request to each terminal that has sent the connection request to the terminal to request that the connection request be retried after a predetermined time;
Reserving radio resource allocation for each terminal within the predetermined time with reference to an allocation management table indicating the status of radio resource allocation within the own station based on each connection request transmitted from each terminal; ,
Receiving a retry request transmitted from each of the terminals after a predetermined period of time;
Performing allocation control to each terminal using the reserved radio resource allocation;
A spatial multiplexing slot allocation method including: The spatial multiplex slot allocation method according to claim 1,
The allocation management table has slot system information indicating whether each radio resource allocation is based on a sub-slot system,
The spatial multiplex slot allocation method includes:
A first determination step of determining whether or not each connection request transmitted from each terminal is a narrowband call;
The step of booking comprises:
With reference to the slot method information stored in the allocation management table, the first determination step is performed for a single subslot that does not form a subslot pair among existing radio resource allocations by the subslot method. A terminal having a connection request determined to be a narrowband call at 1 reserves radio resource allocation so as to form a sub-slot pair with the single sub-slot.
A spatial multiplex slot assignment method characterized by the above. The spatial multiplex slot allocation method according to claim 1,
A first determination step of determining whether or not each connection request transmitted from each terminal is a narrowband call;
The step of booking comprises:
Reserving radio resource allocation in a subslot scheme so as to form a subslot pair by two terminal calls determined to be narrowband calls in the first determination step.
A spatial multiplex slot assignment method characterized by the above. The spatial multiplex slot allocation method according to claim 1,
The allocation management table has slot system information indicating whether each radio resource allocation is based on a sub-slot system,
The spatial multiplex slot allocation method includes:
Determining whether the moving speed of each terminal exceeds a predetermined value;
The step of booking comprises:
With reference to the slot method information stored in the allocation management table, in the determination step for a single subslot that does not form a subslot pair among existing radio resource allocations by the subslot method. A terminal having a connection request determined to have a moving speed exceeding a predetermined value reserves radio resource allocation so as to form a subslot pair with the single subslot.
A spatial multiplex slot assignment method characterized by the above. The spatial multiplex slot allocation method according to claim 1,
Determining whether the moving speed of each terminal exceeds a predetermined value;
The step of booking comprises:
Reserving radio resource allocation in a subslot manner so as to form a subslot pair by two terminal calls determined to have a moving speed exceeding a predetermined value in the determining step;
A spatial multiplex slot assignment method characterized by the above. The spatial multiplexing slot allocation method according to claim 2,
As a result of the determination in the first determination step, if there is a terminal having a connection request determined not to be a narrowband call, whether or not the moving speed of the terminal determined to be not a narrowband call exceeds a predetermined value. A second determination step for determining;
The step of booking comprises:
With reference to the slot method information stored in the allocation management table, the first determination step is performed for a single subslot that does not form a subslot pair among existing radio resource allocations by the subslot method. The connection requesting terminal, which is determined to be a narrow-band call at step 2 or determined to have a moving speed exceeding a predetermined value in the second determination step, forms a subslot pair with the single subslot. To reserve radio resource assignments,
A spatial multiplex slot assignment method characterized by the above. The spatial multiplexing slot allocation method according to claim 3,
As a result of the determination in the first determination step, if there is a terminal having a connection request determined not to be a narrowband call, whether or not the moving speed of the terminal determined to be not a narrowband call exceeds a predetermined value. A second determination step for determining;
The step of booking comprises:
Reserving radio resource allocation in a subslot manner so as to form a subslot pair by two terminal calls determined to have a moving speed exceeding a predetermined value in the determining step;
A spatial multiplex slot assignment method characterized by the above. An adaptive array base station that communicates with a plurality of terminals using a spatial multiplexing slot allocation method,
A receiving unit for receiving each connection request transmitted from each terminal;
A transmission unit that transmits to each terminal a retry request that requests the terminal that has transmitted the connection request received by the reception unit to retry the connection request after elapse of a predetermined time;
Reservation management for reserving radio resource allocation for each terminal within the predetermined time with reference to an allocation management table indicating the status of radio resource allocation in the own station based on each connection request transmitted from each terminal And
An allocation control unit configured to perform allocation control on each terminal using the reserved radio resource allocation after receiving a retry request transmitted from each terminal after the predetermined time has elapsed by the receiving unit;
An adaptive array base station. In the adaptive array base station according to claim 8,
A plurality of wireless processing units having the receiving unit and the transmitting unit;
A central control unit having the reservation management unit and the allocation control unit;
An adaptive array base station characterized by that. In the adaptive array base station according to claim 8 or 9,
The allocation management table has slot system information indicating whether each radio resource allocation is based on a sub-slot system,
The adaptive array base station is
A bandwidth determination unit that determines whether each connection request transmitted from each terminal is a narrowband call;
The reservation management unit
With reference to the slot method information stored in the allocation management table, the band determination unit performs the determination on a single subslot that does not form a subslot pair in the existing radio resource allocation by the subslot method. A terminal having a connection request determined to be a narrowband call reserves a radio resource allocation so as to form a subslot pair with the single subslot.
An adaptive array base station characterized by that. In the adaptive array base station according to claim 8,
A bandwidth determination unit that determines whether each connection request transmitted from each terminal is a narrowband call;
The reservation management unit
Reserving radio resource allocation by a subslot method so as to form a subslot pair by two terminal calls determined to be narrowband calls by the band determining unit;
An adaptive array base station characterized by that. In the adaptive array base station according to claim 8 or 9,
The allocation management table has slot system information indicating whether each radio resource allocation is based on a sub-slot system,
The adaptive array base station is
A moving speed determination unit that determines whether the moving speed of each terminal exceeds a predetermined value;
The reservation management unit
With reference to the slot method information stored in the allocation management table, the moving speed determination unit for the single subslot that does not form a subslot pair in the existing radio resource allocation by the subslot method The terminal determined to have a moving speed exceeding a predetermined value by the above reserves a radio resource allocation so as to form the single subslot and the subslot pair.
An adaptive array base station characterized by that. In the adaptive array base station according to claim 8,
A moving speed determination unit that determines whether the moving speed of each terminal exceeds a predetermined value;
The reservation management unit
Reserving radio resource allocation by a subslot method so as to form a subslot pair by two calls of a terminal determined to have a moving speed exceeding a predetermined value by the moving speed determination unit;
An adaptive array base station characterized by that.

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