JP2004328637A - Channel allocation method and base station apparatus using the same - Google Patents

Abstract

An object of the present invention is to improve the allocation probability even after all channels have been allocated.
A control channel processing unit processes a control signal with a terminal device. The channel allocating unit 20 allocates a channel to a terminal device. Information on the assigned channels is stored in the storage unit 24. When the channel allocation unit 20 allocates the maximum number of channels that can be allocated, and when a link terminal establishment request is issued from a new terminal device, the determination unit 26 determines whether there is a short-term use channel among the already allocated channels. Check. If there is a short-term scheduled channel, after the short-term scheduled channel ends, the terminal device responds to the link channel establishment request, that is, performs channel assignment.
[Selection] Figure 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a channel allocation technology and a base station device using the same. In particular, the present invention relates to a channel assignment method when the number of terminal devices to be communicated is the maximum communicable number and a base station device using the same.
[0002]
[Prior art]
Among conventional wireless communication systems, for example, in a simplified mobile phone system, a base station device allocates a communication channel to a terminal device. An example of the channel assignment is as follows. The terminal device transmits a link channel establishment request to the base station device, but if the base station device cannot allocate a valid free channel, the base station device transmits a link channel assignment rejection notification. The terminal device that has received the link channel assignment rejection notification transmits a link channel establishment request to another base station device or, after a certain period of time, sends a link channel establishment request again to the same base station device. Send. In particular, in the former case, the terminal device transmits a channel establishment request to another base station device one after another until a link channel is allocated, but links to all base station devices recognizable from the terminal device. When the channel assignment is rejected or the number of repetitions of the request reaches a preset number, the above processing is generally terminated because the link channel has not been assigned (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP 2001-103543 A
[Problems to be solved by the invention]
For example, when the terminal device is notified of the rejection of the establishment of the link channel to the base station device, the terminal device searches for a new base station device and transmits a new channel establishment request to the base station device. Requires a certain period of time. Further, due to the period, the link channel establishment request of the terminal device may time out. As a result, the connection probability of the terminal device to the base station device decreases.
[0005]
On the other hand, if there is a channel that the base station apparatus allocates to the terminal device, such as a call or a communication, which is generally used for a long period of time, location registration and a short message service (hereinafter, referred to as “SMS”) are used. Some are used for a short time. Note that the location registration is executed for the purpose of registering a location in a base station device connectable to the terminal device, even when a call is not being made, in order to enable an incoming call to the terminal device. Also, in general, a terminal device transmits a link channel establishment request in order from the base station device expected to have the best communication quality, so that a channel can be allocated from the base station device that first transmitted the link channel establishment request. In many cases, the communication quality is improved. In addition, the feasibility of the system is higher if the terminal device is not modified.
[0006]
The present inventor has recognized the above situation and made the present invention. It is an object of the present invention to provide a channel allocation method for increasing the connection probability of a terminal device even when the maximum possible number of channels is allocated, and a method for the same. It is to provide a used base station apparatus.
[0007]
[Means for Solving the Problems]
One embodiment of the present invention relates to a base station device. The device includes a communication unit that communicates with a predetermined terminal device, a channel allocation unit that allocates a channel for communication to the terminal device that communicates, and a period detection unit that detects a scheduled use period of the allocated channel. . In this device, the channel allocating unit, if there is no channel that can be allocated in response to a channel allocation request from a new terminal device, if there is a channel whose scheduled use period is shorter than a predetermined threshold among all the channels, After the use of the channel is completed, the channel may be allocated to a new terminal device.
[0008]
The “channel” refers to a wireless communication path set for performing communication between a base station device and a wireless device such as a terminal device. Specifically, in the case of FDMA (Frequency Division Multiple Access), it is specified. In the case of TDMA (Time Division Multiple Access), it refers to a specific time slot, and in the case of CDMA (Code Division Multiple Access), it refers to a specific code sequence, but these are not distinguished here. .
[0009]
"Scheduled use period" is not a unit of time, except when it is expressed in units of time. For example, it is expressed by a classification corresponding to a period such as "control signal" or "data signal". This includes the case where
[0010]
With the above device, even if there is no channel that can be allocated to the terminal device, the channel is allocated to the terminal device after the terminal device is made to wait, so that the channel can be allocated reliably.
[0011]
The channel allocating unit sets a value equal to or less than a predetermined period until a terminal device outputs a channel assignment request to a channel assignment request to another base station device again when there is no response corresponding to the channel assignment request after outputting the channel assignment request. The threshold may be set.
[0012]
The channel assignment unit assigns a dummy channel to the new terminal device when there is no assignable channel in response to a channel assignment request from the new terminal device, and furthermore, a scheduled use period of all the channels is a predetermined period. A channel shorter than the threshold may be newly assigned as a formal channel after use.
[0013]
Another embodiment of the present invention relates to a channel allocating method. The method includes the steps of: receiving a channel assignment request from a predetermined terminal device; and, if there is no channel that can be allocated to the predetermined terminal device, select a channel whose scheduled use period is shorter than a predetermined threshold value from all channels. And assigning the channel to a predetermined terminal device after the use of the detected channel ends.
[0014]
Still another preferred embodiment according to the present invention relates also to a channel assignment method. The method includes the steps of: receiving a channel assignment request from a predetermined terminal device; and, if there is no channel that can be allocated to the predetermined terminal device, select a channel whose scheduled use period is shorter than a predetermined threshold value from all channels. And waiting for a predetermined terminal device on the assumption that the detected channel is allocated.
[0015]
Still another preferred embodiment according to the present invention relates also to a channel assignment method. The method includes the steps of: receiving a channel assignment request from a predetermined terminal device; and, if there is no channel that can be allocated to the predetermined terminal device, select a channel whose scheduled use period is shorter than a predetermined threshold value from all channels. And transmitting a signal indicating connection refusal to a predetermined terminal device on the assumption that no channel is allocated when there is no channel whose scheduled use period is shorter than the predetermined threshold value.
[0016]
Still another preferred embodiment according to the present invention relates to a program. The program includes a step of receiving a channel allocation request from a predetermined terminal device via a wireless network, and a step of, when there is no channel that can be allocated to the predetermined terminal device, determining a scheduled use period of all channels from a memory. Detecting a channel shorter than the threshold and allocating the channel to a predetermined terminal device after use of the detected channel is completed.
[0017]
It is to be noted that any combination of the above-described components and any conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, and the like are also effective as embodiments of the present invention.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
Embodiment 1 Embodiment 1 relates to a base station device capable of communicating with a plurality of terminal devices in a simplified mobile phone system. The base station device allocates a channel when communicating with the terminal device. Some channels may be used for a long period of time in response to a call or data communication, and some channels may be used in a relatively short time in response to location registration or SMS. Some channels are used during interim. In particular, it is difficult to predict the use end time of the former, but the latter can be easily predicted. The base station apparatus according to the present embodiment confirms the type of the already allocated channel if there is no channel that can be allocated when a new terminal apparatus requests connection. If there is a channel used for a short period among the already allocated channels, the terminal device that has made the connection request is kept waiting, and when the use of the channel ends, the channel is allocated to the terminal device. In general, a channel used for a short period of time is terminated in about several seconds, so that the terminal device can communicate in about several seconds. On the other hand, if there is no channel used for a short period among the already allocated channels, a notification of connection non-permission is transmitted to the terminal device as in the related art.
[0019]
FIG. 1 shows a communication system 100 according to the first embodiment. The communication system 100 includes a base station device 10, a base station antenna 14, a first terminal device 12a, a second terminal device 12b, and a third terminal device 12c collectively referred to as a terminal device 12.
The terminal device 12 is connected to the base station antenna 14 to provide a communication function to the user. The communication functions include location registration, SMS, and the like, in addition to telephone calls and data communication.
[0020]
The base station device 10 has a base station antenna 14, and further assigns a channel to each of the plurality of terminal devices 12 and connects the plurality of terminal devices 12. Here, it is assumed that a maximum of three terminal devices 12 can be connected to one base station device 10, and that the terminal devices 12 are connected to the exchange by a wired line (not shown).
[0021]
FIG. 2 shows a configuration of the base station device 10. The base station device 10 includes a base station antenna 14, a radio unit 16, a modem unit 18, a channel allocation unit 20, a control channel processing unit 22, and a storage unit 24. The channel allocation unit 20 includes a determination unit 26. The determination unit 26 includes a period detection unit (not shown).
The base station antenna 14 transmits and receives radio frequency signals to and from the terminal device 12 via a radio transmission path.
[0022]
The radio unit 16 performs frequency conversion between a signal modulated or demodulated by a modulation / demodulation unit 18 to be described later and a radio frequency signal. In addition, D / A conversion, A / D conversion, and amplification processing are also performed.
[0023]
The modulation / demodulation unit 18 modulates / demodulates information signals by π / 4 shift QPSK (Quadrature Phase Shift Keying), which is performed by digital signal processing. In addition, since the base station device 10 is communicating with the plurality of terminal devices 12 as shown in FIG. 1, the modulation / demodulation unit 18 executes the modulation / demodulation processing on a terminal device 12 basis.
[0024]
The control channel processing unit 22 processes a control signal with the terminal device 12. The control signal includes an uplink control signal output from terminal apparatus 12 to base station apparatus 10 and a downlink control signal output from base station apparatus 10 to terminal apparatus 12, and further includes a downlink control signal. The line control signal includes a control signal transmitted separately to each terminal device 12 and a control signal simultaneously broadcast to a plurality of terminal devices 12 including the terminal device 12 not communicating. Then, they will be referred to as control signals without distinction. Note that the uplink control signal includes a link channel establishment request.
[0025]
Channel allocating section 20 allocates a channel to terminal apparatus 12 communicating with base station apparatus 10. There are a plurality of types of allocated channels, at least a channel that is generally used for a long period of time (hereinafter, referred to as a “long-term use channel”), such as a communication channel or a data communication channel, and a location registration channel. And short-term channels such as SMS channels (hereinafter referred to as “short-term scheduled channels”). Information on the assigned channels is stored in the storage unit 24. FIG. 3 shows a data structure of the channel information stored in the storage unit 24. Since the base station device 10 is communicating with three terminal devices 12, the channel number is set up to three. The storage unit 24 stores the identification number of the terminal device 12 corresponding to the channel number and the purpose of use of the channel being used, that is, “call” or “location registration”. Furthermore, the use start time of each channel is also recorded, and indicates the use from "12:05:12", "12: 8: 35", and "12: 10: 5", respectively.
[0026]
When the channel allocation unit 20 allocates the maximum number of channels that can be allocated and, when a new terminal device 12 requests a link channel establishment, the determination unit 26 uses the period detection unit to determine which channel has already been allocated. Check the existence of short-term use channel of. If there is a short-term use channel, the use end time is estimated from the use start time of the channel. If the use end time is earlier than the time-out time (hereinafter referred to as “permissible period”) of the terminal device 12 that has issued a new link channel establishment request, the link channel establishment request is temporarily left, and after the end of the short-term use scheduled channel, the terminal ends. The device 12 responds to the link channel establishment request, that is, performs channel assignment. On the other hand, if there is no short-term scheduled channel, or if the use end time of the short-term scheduled channel is later than the time-out time of the terminal device 12, the terminal device 12 transmits a link channel assignment rejection notification to the terminal device 12.
[0027]
This configuration can be realized in hardware by a CPU, a memory, or other LSI of any computer, and is realized in software by a program having a reservation management function loaded into a memory. The functional blocks realized by their cooperation are drawn. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.
[0028]
FIG. 4 is a sequence diagram of the location registration. Using this sequence diagram, a procedure for determining that the purpose of use of the channel is “location registration” will be described. The terminal device 12 transmits a link channel establishment request to the base station device 10 (S10). When the channel assignment unit 20 in the base station device 10 has assigned a channel, the base station device 10 transmits a link channel assignment to the terminal device 12 (S12). The base station device 10 and the terminal device 12 enter a TCH established state (S14), and the terminal device 12 transmits an MM location registration request to the base station device 10 (S16). Upon receiving the MM location registration request, the base station apparatus 10 recognizes that the channel allocated to the terminal apparatus 12 has been used for location registration (S18), and as a result, recognizes it as a short-term use scheduled channel. For the position registration, the processing from step 20 to step 38 is executed, but the description is omitted here. Finally, the base station apparatus 10 transmits an RT wireless channel disconnection to the terminal apparatus 12 (S40), and the terminal apparatus 12 transmits an RT wireless channel disconnection completion to the base station apparatus 10 (S42). To end.
[0029]
FIG. 5 is a sequence diagram of the SMS. Using this sequence diagram, a procedure for determining that the purpose of use of the channel is “SMS” will be described. The terminal device 12 transmits a link channel establishment request to the base station device 10 (S50). When the channel assignment unit 20 in the base station device 10 has assigned the channel, the base station device 10 transmits the link channel assignment to the terminal device 12 (S52). The base station apparatus 10 and the terminal apparatus 12 enter a TCH established state (S54), and the terminal apparatus 12 transmits a CC setup to the base station apparatus 10 (S56). If there is UUI information in the received CC setup, the base station device 10 recognizes that the channel allocated to the terminal device 12 has been used for SMS (S58), and as a result, recognizes it as a short-term scheduled channel. The SMS executes the processing from step 60 to step 84, but the description is omitted here. Finally, the communication state is established (S86).
[0030]
FIG. 6 is a flowchart of channel assignment. The control channel processing unit 22 receives the link channel establishment request (S200). The channel allocating unit 20 checks the content stored in the storage unit 24, and if there is no vacant channel (N in S202), the determining unit 26 checks whether there is a communication scheduled to end within the allowable period. If there is a communication scheduled to be completed within the allowable period (Y in S204), the channel allocating unit 20 temporarily stops the link channel establishment request from the terminal device 12, waits for the end of the communication (S206), and ends the communication. Then, the link channel assignment is transmitted to the terminal device 12 (Y in S208) (S210). On the other hand, as a result of the determination by the determination unit 26, if there is no communication scheduled to end in the allowable period (N in S204) or if the communication does not end within the allowable period (N in S208), the A link channel assignment rejection is transmitted to the device 12 (S212). If there is a free channel (Y in S202), the channel allocating unit 20 transmits a link channel allocation to the terminal device 12 (S210).
[0031]
FIG. 7 is a sequence diagram of channel assignment. Here, the allowable period of the terminal device 12 is such that if the terminal device 12 transmits a signal to the base station device 10 and the base station device 10 does not respond to the transmitted signal, the terminal device 12 The signal is retransmitted to the device 10, but is defined as a period corresponding to a case where there is no response after four retransmissions. The terminal device 12 transmits a link channel establishment request to the base station device 10 (S150). When there is no channel that can be allocated to the terminal device 12 and there is a channel to be used for a short time, the base station device 10 leaves the link channel establishment request in order to wait for the end of the channel to be used for a short time. No response to 12.
[0032]
The terminal device 12 transmits a second link channel establishment request to the base station device 10 (S152). The terminal device 12 transmits a third link channel establishment request to the base station device 10 (S154). The terminal device 12 transmits a fourth link channel establishment request to the base station device 10 (S156). The base station device 10 transmits the link channel assignment to the terminal device 12 because the short-term use channel has ended (S158). Thereafter, a predetermined connection process is executed (S160).
[0033]
The operation of the base station apparatus 10 having the above configuration will be described. The base station device 10 has already communicated with the three terminal devices 12, and has allocated two long-term scheduled channels and one short-term scheduled channel. The control channel processing unit 22 receives a link channel establishment request from a new terminal device 12. The channel allocation unit 20 checks the allocated channel based on the storage content of the storage unit 24, and the determination unit 26 checks the existence of the short-term use scheduled channel scheduled to end within the allowable period of the terminal device 12.
The channel assignment unit 20 receives the link channel establishment request from the terminal device 12 again so as not to respond to the link channel establishment request from the terminal device 12. When confirming the end of the short-term use channel, the channel allocating unit 20 determines channel allocation to the terminal device 12, and the control channel processing unit 22 transmits the link channel allocation to the terminal device 12. Thereafter, communication with the terminal device 12 is performed according to a normal procedure.
[0034]
According to the present embodiment, even when a new channel cannot be allocated, the number of times of rejection of channel allocation by the base station apparatus can be reduced in order to wait for the end of a channel that is scheduled to end soon. In addition, since the terminal device can be connected to the base station device having better communication quality, it is possible to improve the call connection rate, the base station device operation rate, and the call quality.
[0035]
(Embodiment 2)
Embodiment 2 relates to a base station apparatus in the same manner as Embodiment 1, and when there is no channel that can be allocated when a new terminal device requests a connection, a short-term use can be made among already allocated channels. If there is a channel to be connected, the terminal device that has made the connection request is made to wait. However, different from the first embodiment, the base station apparatus assigns a dummy channel to the terminal apparatus and pseudo-progresses the connection processing with the terminal apparatus. Further, when the use of the channel used for a short period ends, the channel is newly allocated to the terminal device. By allowing the base station device to proceed with the pseudo connection process with the terminal device, the probability that the terminal device times out because there is no response from the base station device can be reduced, and as a result, the terminal device can be used for a longer period of time. I can make you wait.
1 is effective as the communication system 100 in the second embodiment, and the one shown in FIG. 2 is effective as the base station device 10.
[0036]
FIG. 8 is a sequence diagram of channel assignment according to Embodiment 2. Here, too, the allowable period of the terminal device 12 is defined as described above. The terminal device 12 transmits a link channel establishment request to the base station device 10 (S250).
When there is no channel that can be allocated to the terminal device 12 and there is a channel to be used for a short time, the base station device 10 leaves the link channel establishment request in order to wait for the end of the channel to be used for a short time. No response to 12. The terminal device 12 transmits a second link channel establishment request to the base station device 10 (S252). The terminal device 12 transmits a third link channel establishment request to the base station device 10 (S254). The terminal device 12 transmits a fourth link channel establishment request to the base station device 10 (S256).
[0037]
The base station device 10 transmits a link channel assignment to the terminal device 12 before the end of the short-term use channel (S258). This allocated channel is a non-existent channel and is a dummy channel. The base station device 10 transmits a TCH synchronization burst to the terminal device 12 (S260). The base station device 10 leaves the TCH synchronization burst and does not respond to the terminal device 12 because the short-term use channel has not ended. The terminal device 12 transmits a second TCH synchronization burst to the base station device 10 (S262). The terminal device 12 transmits a third TCH synchronization burst to the base station device 10 (S264). The terminal device 12 transmits the fourth TCH synchronization burst to the base station device 10 (S266). The base station device 10 transmits the link channel assignment to the terminal device 12 in order to assign a formal channel to the terminal device 12 because the short-term use channel has ended (S268). Thereafter, a predetermined connection process is performed (S270).
[0038]
The operation of the base station apparatus 10 having the above configuration will be described. The base station device 10 has already communicated with the three terminal devices 12, and has allocated two long-term scheduled channels and one short-term scheduled channel. The control channel processing unit 22 receives a link channel establishment request from a new terminal device 12. The channel assignment unit 20 checks the assigned channel based on the storage content of the storage unit 24, and checks the existence of a short-term use scheduled channel that the determination unit 26 is scheduled to end within the allowable period of the terminal device 12. The channel assignment unit 20 receives the link channel establishment request from the terminal device 12 again so as not to respond to the link channel establishment request from the terminal device 12.
Furthermore, in order not to respond, a total of four link channel establishment requests are received.
[0039]
The channel allocating unit 20 allocates a dummy channel to the terminal device 12 before the end of the short-term scheduled channel, and the control channel processing unit 22 transmits a link channel allocation to the terminal device 12. Next, a TCH synchronization burst is received from the terminal device 12. The channel allocation unit 20 receives the TCH synchronization burst from the terminal device 12 again so as not to respond to the TCH synchronization burst from the terminal device 12. When confirming the end of the short-term use channel, the channel allocating unit 20 determines channel allocation to the terminal device 12, and the control channel processing unit 22 transmits the link channel allocation to the terminal device 12. Thereafter, communication with the terminal device 12 is performed according to a normal procedure.
[0040]
According to the present embodiment, a process is allowed to proceed after a dummy channel is allocated to a terminal device, and then a formal channel is allocated, so that the period during which the terminal device waits can be extended. Further, the terminal device does not need to be remodeled, so that the terminal device is easily realized.
[0041]
The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and that such modifications are also within the scope of the present invention. is there.
[0042]
In the first to third embodiments, the communication system 100 is directed to a simple mobile phone system. However, the present invention may be applied to a mobile phone system or a third-generation mobile phone system. According to this modification, the present invention can be applied to various wireless communication systems. That is, any system may be used as long as the base station device 10 allocates a channel to the terminal device 12 for communication.
[0043]
【The invention's effect】
According to the present invention, even when the maximum possible number of channels is allocated, the connection probability of the terminal device can be increased.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a communication system according to a first embodiment.
FIG. 2 is a diagram illustrating a configuration of a base station apparatus of FIG. 1;
FIG. 3 shows a data structure of a storage unit in the base station apparatus of FIG.
FIG. 4 is a sequence diagram of location registration in the base station device of FIG. 2;
FIG. 5 is a sequence diagram of short message communication in the base station device of FIG. 2;
FIG. 6 is a flowchart of channel assignment in the base station apparatus of FIG. 2;
FIG. 7 is a sequence diagram of channel assignment in the base station apparatus of FIG. 2;
FIG. 8 is a sequence diagram of channel assignment according to Embodiment 2.
[Explanation of symbols]
Reference Signs List 10 base station apparatus, 12 terminal apparatus, 14 base station antenna, 16 radio section, 18 modem section, 20 channel allocation section, 22 control channel processing section, 24 storage section, 26 determination section, 100 communication system.

Claims (7)

A communication unit that communicates with a predetermined terminal device;
A channel allocating unit that allocates a channel for communication to the terminal device for communication,
Including a period detection unit that detects a scheduled use period of the allocated channel,
In response to a channel assignment request from a new terminal device, if there is no channel that can be assigned, if there is a channel whose scheduled use period is shorter than a predetermined threshold value, The base station device is allocated to the new terminal device after use of the base station device. The channel allocating unit, when the terminal device outputs a channel allocation request and there is no response corresponding to the channel allocation request, a value equal to or less than a period until a channel allocation request is output to another base station device again. The base station device according to claim 1, wherein the predetermined threshold value is set. In response to a channel assignment request from a new terminal device, if there is no channel that can be assigned, the channel assignment unit assigns a dummy channel to the new terminal device. 2. The base station apparatus according to claim 1, wherein a channel shorter than a predetermined threshold is newly assigned as a formal channel after use is completed. Receiving a channel assignment request from a predetermined terminal device;
When there is no channel that can be allocated to the predetermined terminal device, from among all the channels, a step of detecting a channel whose scheduled use period is shorter than a predetermined threshold, and after the use of the detected channel ends, Allocating the channel to the predetermined terminal device. Receiving a channel assignment request from a predetermined terminal device;
When there is no channel that can be allocated to the predetermined terminal device, a step of detecting a channel whose scheduled use period is shorter than a predetermined threshold from all channels, and assuming that the detected channel is allocated. Waiting the predetermined terminal device. Receiving a channel assignment request from a predetermined terminal device;
When there is no channel that can be allocated to the predetermined terminal device, a step of detecting a channel whose scheduled use period is shorter than a predetermined threshold from all the channels; Transmitting a signal indicating connection refusal to the predetermined terminal device on the assumption that no channel is allocated if there is no short channel. Receiving a channel assignment request from a predetermined terminal device via a wireless network;
When there is no channel that can be allocated to the predetermined terminal device, a step of detecting a channel whose scheduled use period is shorter than a predetermined threshold from all the memories from the memory,
Allocating the channel to the predetermined terminal device after use of the detected channel is completed.

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