JPH09200841A - Radio channel assignment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio channel assignment method in which a terminal equipment in existence in area being duplicate service areas by plural radio base stations seeks a communication enable base station easily and surely, concentration of traffic to the radio base station and the deterioration in the service quality of voice speech are prevented. SOLUTION: A terminal equipment 9 receives a multiple address channel from narrow band radio base stations 2, 3 and selects a communication enable narrow band radio base station based on the reception strength RSSI and an idle channel (slot) number included in multiple address information informed by the multiple address channel and the selected narrow band radio base station assigns a radio channel in response to an assignment request of the radio channel from the terminal equipment 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless channel allocation method in which one of a plurality of wireless base stations allocates a wireless channel to a terminal within its service area.

[0002]

2. Description of the Related Art Recently, PHS (Personal Ha)
The service of "ndy Phone System" was started, and the mobile communication has come to receive more attention. PH
In S, voice is encoded at 32 kbit / sec, so that high-speed transmission is possible as compared with the conventional mobile phone. However, it cannot be said that this speed is still sufficient for transmitting still images, moving images and the like.

Therefore, in addition to the conventional PHS bidirectional radio channel, a system has been proposed in which a downlink radio channel having a service area narrower than that of the PHS but sufficiently high speed is added.

In this system, when the voice call and the data call are mixedly used by using PHS, it is necessary to prevent the quality of service of the voice call which is a conventional service from being impaired.

[0005]

High-speed data transmission is performed using the bidirectional narrow band wireless channel provided by the narrow band wireless base station and the downlink wide band wireless channel provided by the wide band wireless base station. In the system, in a radio base station having a normal hierarchical cell structure, a narrow band radio base station that serves a wide range and a wide band radio base station that serves a narrower range cannot communicate with terminals at the same time. In addition, a pair of a narrow band wireless base station and a wide band wireless base station that can communicate with a terminal even if they communicate simultaneously has been uniquely determined. In such a case, when terminals performing data communication are concentrated in one narrow band base station, the number of wireless channels is insufficient, and terminals for voice communication in the area cannot perform voice communication using PHS. There is a problem that it causes deterioration of service quality.

[0006] Conventionally, when a terminal receives a control channel on a control carrier from all radio base stations,
The reception level RSSI (Received Signal Strength I)
ndicator) searches for a wireless base station with a predetermined value or more and selects an appropriate wireless base station, and the selected wireless base station allocates wireless channels according to a wireless channel allocation request from the terminal. It was.

As described above, when each terminal selects a radio base station based only on RSSI, for example, when a plurality of voice communication terminals exist in an area where service areas of a plurality of radio base stations overlap, The traffic is concentrated on one radio base station, and the number of radio channels is insufficient as described above, resulting in deterioration of service quality of voice communication.

Therefore, the present invention has been made in view of the above problems, and searches for a base station with which a terminal existing in an area where the service areas of a plurality of radio base stations overlap can easily and surely communicate. It is an object of the present invention to provide a wireless channel allocation method capable of preventing the concentration of traffic to a certain one wireless base station and the deterioration of the service quality of voice communication caused thereby.

In addition, when a downlink wideband wireless channel is added to a bidirectional narrowband wireless channel to realize a multimedia wireless communication service, service areas of a plurality of narrowband wireless base stations exist in an overlapping area. A wireless channel assignment that allows a terminal to easily and surely find a base station with which communication can be reliably performed, and prevent traffic concentration on one narrow-band wireless base station and the resulting deterioration of service quality of voice calls. The purpose is to provide a method.

[0010]

The wireless channel allocation method of the present invention is a wireless channel allocation method in which one of a plurality of wireless base stations allocates a wireless channel to a terminal within its service area. Each of the base stations broadcasts broadcast information including at least the identification information of its own station and the number of vacant wireless channels with which it can communicate to the terminal through a predetermined wireless channel, and the terminal broadcasts the broadcast information. Upon receiving a wireless channel, a wireless base station capable of communication is selected from the plurality of wireless base stations based on the reception intensity level and the number of free wireless channels included in the broadcast information, and the selected wireless base station Assigns a wireless channel in response to a wireless channel assignment request from the terminal so that the service areas of a plurality of wireless base stations overlap. Can terminals existing authors easily and Find reliably communicable base stations, it is possible to prevent the concentration of traffic to a certain one of the radio base station, it by the degradation of service quality for voice calls.

Also, the radio channel allocation method of the present invention provides a plurality of narrow band radio base stations providing bidirectional radio channels and a broadband radio channel providing a downlink wideband radio channel having a wider bandwidth than the bidirectional radio channels. Base stations are communicably connected to each other, one of the plurality of narrowband radio base stations assigns a bidirectional radio channel to a terminal within its coverage area, and the broadband radio base station serves the coverage area. In the wireless channel allocation method for allocating the downlink wideband wireless channel to the terminal, each of the plurality of narrowband wireless base stations includes broadcast information including at least identification information of its own station and the number of vacant wireless channels with which communication is possible. Is broadcast to the terminal on a predetermined wireless channel, and the terminal broadcasts the broadcast information to a wireless channel. Priority is given to the narrow band wireless base station having the maximum number of free channels included in the broadcast information when the reception strength level of the received wireless channels from the plurality of narrow band wireless base stations is equal to or higher than a predetermined value. Select to
The selected narrowband wireless base station and the wideband wireless base station allocate a plurality of narrowband wireless channels by respectively allocating the bidirectional wireless channel and the downlink wideband wireless channel in response to a wireless channel allocation request from the terminal. A terminal existing in an area where the service areas of wireless base stations overlap can easily and surely find a base station with which communication is possible, and the traffic is concentrated on a certain narrow band wireless base station, and the resulting voice call is made. It is possible to prevent the deterioration of the service quality.

Also, the radio allocation method of the present invention comprises a plurality of narrow band radio base stations providing bidirectional radio channels and a broadband radio base station providing downlink wide band radio channels having a wider bandwidth than the bidirectional radio channels. Stations are communicatably connected to each other, one of the plurality of narrowband radio base stations assigns a bidirectional radio channel to terminals within its coverage area, and the broadband radio base station is within its coverage area. In the wireless channel allocation method for allocating the downlink wideband wireless channel to the terminal, the wideband wireless base station, at least the identification information of its own station, and the communication obtained with the plurality of narrowband wireless base stations, Identification information of the narrow band base station whose service area overlaps with that of the wide band radio base station and the narrow band radio base station Broadcast information including the number of available free wireless channels to the terminal, and the terminal can communicate from the plurality of narrow band wireless base stations based on the number of available wireless channels included in the received broadcast information. A narrow band wireless base station, and the selected narrow band wireless base station and the wide band wireless base station select the narrow band wireless base station and the wide band wireless base station according to a wireless channel allocation request from the terminal. By assigning
A terminal existing in an area where the service areas of a plurality of narrowband wireless base stations overlap can easily and reliably search for a base station with which communication can be performed, and the concentration of traffic to a certain narrowband wireless base station, It is possible to prevent the deterioration of the service quality of the voice call due to it.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of a communication system according to this embodiment. In FIG. 1, the network 1 is connected with narrowband wireless base stations 2 and 3 each having a wireless interface with a bidirectional low-speed wireless transmission rate (for example, several tens Kbps to several Mbps), and a downlink (base station). Wideband wireless base stations 4, 5 and 6 having a wireless interface with a high wireless transmission rate (for example, 10 Mbps) from the station to the terminal are connected.

The narrow band wireless service area formed by the narrow band wireless base stations 2 and 3 is larger than the wide band wireless service area formed by the wide band wireless base station, and there are a plurality of wide band wireless service areas within the narrow band wireless service area. May be. Further, adjacent narrow band wireless service areas are arranged so as to partially overlap each other. A broadband wireless service area may also exist in an area where a plurality of narrowband wireless service areas overlap (for example,
Service area formed by the broadband wireless base station 6).

Radio communication terminal (hereinafter simply referred to as terminal)
9 is connected to the network 1 via the low-speed bidirectional wireless channel provided by the narrowband wireless base station and the high-speed downlink wireless channel provided by the wideband wireless base station, and is also connected to the network 1. The server 7 receives a service (providing desired data, etc.).

FIG. 2 shows the configuration of the terminal 9. In FIG. 2, the terminal 9 has an antenna 21 and a narrowband transceiver 23 for transmitting and receiving data to and from the narrowband wireless base station via a bidirectional wireless channel, and a downlink wireless channel from the wideband wireless base station. Antenna 22 and wideband receiver 2 for receiving data via
4. The user operates the operation unit 25 as a user interface for inputting various instructions, the narrow band transceiver 23 or the wide band receiver 24 to output voices, images and data, or the user desires. Voice, image,
An input / output unit 28 for inputting data, a control unit 2 that is connected to the narrow band transceiver 23, the wide band receiver 24, the operation unit 25, and the input / output unit 28 and controls the entire operation.
6.

Narrowband transceiver 23, wideband receiver 24
Receives the control channel (broadcast channel) on the control carrier from the narrow band wireless base station and the wide band wireless base station, respectively, and the control unit 26 receives the received intensity level RS.
Based on the SI and the broadcast information transmitted on the control channel, it is possible to communicate from a plurality of narrow band wireless base stations while updating the table 27 provided in the control unit 26, for example, as shown in FIG. It is designed to select a suitable base station.

In the following description, the terminal 9 exists in the service area of the broadband wireless base station 6, and the area is covered by the service areas of the narrowband wireless base stations 2 and 3. (See FIG. 1).

Next, with reference to FIG. 4, a method of allocating radio channels to the terminal 9 of the communication system shown in FIG. 1 will be described. That is, after the power of the terminal 9 is turned on, the terminal 9 has the narrow band wireless base station (here, one of the narrow band wireless base stations 2 and 3) and the wide band wireless base station (here, the wide band wireless base station). The operation of selecting the station 6) and the selected wireless base station allocating the wireless channel to the terminal 9 will be described.

Here, at least the information of each narrow band wireless base station is included in the information broadcast from each narrow band wireless base station to each terminal on the broadcast channel (hereinafter referred to as broadcast information). It is assumed that the information and the number of vacant channels that can be communicated by the base station are included.

When the user operates the operation unit 25 to turn on the power of the terminal 9, the narrow band transceiver 23 is first provided.
Is turned on (step S1), the narrowband transceiver 23 receives the broadcast channels of the narrowband wireless base stations 2 and 3 and measures the reception strength RSSI thereof (step S1).
2) Based on that, the control unit 26 creates the table 27 as shown in FIG. 3 (step S3).

At this stage, the table 27 stored in the control unit 26 stores the measured RSSI value corresponding to the identification information of each narrow band radio base station, as shown in FIG. It is like this.

Next, with reference to the table 27 of FIG. 3, the terminal 9 receives the broadcast information in the order of, for example, the narrow band wireless base stations having the highest RSSI values, and the broadcast information is included in the broadcast information. The number of free channels is stored in the table 27 as shown in FIG. 3 stored in the control unit 26 (step S
4).

At this stage, in the table 27 stored in the control unit 26, as shown in FIG. 3, the measured RSSI and the number of free channels are stored corresponding to the identification information of each narrow band radio base station. It is supposed to be done.

With reference to the RSSI and the number of free channels stored in the table 27, the control unit 26 selects the optimum (communicable) narrow band wireless base station to be connected (step S5).

When the narrow band wireless base station can be selected (in this case, the narrow band wireless base station 2), the function of the wide band receiver 24 is turned on (step S6), and the wide band wireless base station switches to a predetermined broadcast channel. Receive the broadcast information that is broadcast by
The control unit 26 stores the identification information of the broadband base station 6 included in the received broadcast information (step S7).

Next, a communication request message is transmitted to the narrow band wireless base station 2 selected in step S5. At this time, the message includes the identification information of the wide band wireless base station stored in step S7. (Step S8).

Upon receiving the communication request message from the terminal 9, the narrow band wireless base station 2 calls the wide band wireless base station 6 based on the identification information of the wide band wireless base station 6 included in the communication request message. Settings are made (step S9). That is, the broadband wireless base station 6 controls the terminal 9 to allocate a downlink broadband wireless channel. Further, an empty channel (empty slot) is assigned to the terminal 9 that has made the communication request (step S10). Then, the terminal 9 starts communication with the narrowband wireless base station 2 and the wideband wireless base station 6 via the assigned wireless channel.

In FIG. 4, the narrow band transceiver 2
3. On / off of the function of the wideband receiver 24 may be performed by the user operating the operation unit 25 or by the control of the control unit 26.

Next, with reference to the flow chart shown in FIG. 5, a detailed processing operation in the control unit 26 when selecting a narrow band radio base station will be described. Here, RSS
Let N be the number of narrow-band wireless base stations that are subject to measurement of I.
Further, the threshold of RSSI is T.

First, the narrow band transmitter / receiver 23 of the terminal 9 scans a predetermined frequency from the received radio wave to scan the RSSI.
Is measured (step S20), the control unit 26
A table 27 as shown in FIG. 3 is created in order from the largest RSSI value (highest reception level) (step S21).

Next, the number of empty channels included in the broadcast information broadcast by the narrow band base station having the RSSI larger than the threshold value T is received (step S23), and it is written in the table 27 previously created. (Step S24).

Referring to the table 27, the control unit 26 first selects a narrow band wireless base station having the largest number of free channels (steps S25 to S26). When there are a plurality of channels with the largest number of free channels, the narrow band wireless base station with the largest RSSI is selected from them (step S25, step S26).

In a system in which a downlink wideband wireless channel is further added to the conventional bidirectional narrowband wireless channel of PHS, an area where the service area of the narrowband wireless base station and the service area of the wideband wireless base station overlap ( 1), it is considered that the traffic of the system is increased. That is, as in the conventional case, the terminal 9
However, in the method of selecting the nearest narrow band wireless base station only by RSSI, the traffic is concentrated on a specific narrow band wireless base station. In order to disperse this, by assigning the idle channel to the terminal preferentially from the base station with many idle channels, it is possible to reduce the waiting time for call connection of each terminal and impair the communication quality of service. Disappear.

As described above, according to the above-described embodiment, the terminal 9 existing in the area where the service areas of the narrow band wireless base stations 2 and 3 overlap each other is the broadcast channel from these narrow band wireless base stations. Based on the RSSI and the number of empty channels (slots) included in the broadcast information broadcast on the broadcast channel, the narrowband wireless base station that can communicate is selected, and the selected narrowband The wireless base station allocates a wireless channel in response to a wireless channel allocation request from the terminal 9, so that a terminal existing in an area where the service areas of a plurality of narrowband wireless base stations are overlapped,
It is possible to easily and surely find a base station with which communication is possible. Therefore, as in the past, the broadcast channel RSSI
Compared with the method of selecting a narrow band wireless base station only,
Concentration of traffic on a narrow band wireless base station,
It is possible to prevent the deterioration of the service quality of the voice call due to it.

The terminal 9 is a narrow band radio base station 2, 3
Based on the RSSI of the broadcast channel from and the number of vacant channels (slots) included in the broadcast information broadcast on that broadcast channel, select a narrowband wireless base station that can communicate and select it. The wireless base station and the wideband wireless base station 6 thus assigned respectively allocate a bidirectional narrowband wireless channel and a downlink wideband wireless channel in response to a wireless channel allocation request from the terminal 9, thereby obtaining a plurality of narrowband wireless base stations. Even when the terminal 9 exists in the area where the service areas of (1) and (2) overlap, the terminal 9 can easily and surely search for a base station with which communication is possible. Therefore, it is possible to prevent the concentration of traffic on a certain narrow band radio base station and the deterioration of the service quality of voice communication due to the concentration of traffic.

In the above embodiment, it is assumed that the terminal 9 exists within the service area of the broadband wireless base station 6. However, the present invention is not limited to this case, and the terminal 9 includes at least a plurality of narrow band wireless base stations. The present invention works effectively as long as they exist in the overlapping area.

Next, a second embodiment will be described.
That is, in the communication system having the configuration shown in FIG.
In a communication system in which a terminal 9 communicates via a downlink wideband wireless channel provided by the broadband wireless base station 6 and a bidirectional narrowband wireless channel provided by one of the plurality of narrowband wireless base stations 2 and 3. , For example, one of a plurality of narrow band wireless base stations 2 and 3 when a call is sent from the terminal 9.
FIG. 6 shows another processing operation until one of the terminals 9 in the service area allocates a bidirectional wireless channel and the broadband wireless base station 6 allocates the downlink wideband wireless channel to the terminal 9 in the service area. This will be described with reference to the flowchart shown.

In the following description, the terminal 9 exists in the service area of the broadband wireless base station 6, and
It is assumed that the area is covered by the service areas of the narrow band wireless base stations 2 and 3 (see FIG. 1).

The information (hereinafter, broadcast information) broadcast from the broadband wireless base station 6 to each terminal on a predetermined broadcast channel includes at least its own station (broadband wireless base station 6).
Identification information, identification information of the narrow band wireless base stations 2 and 3 whose service area overlaps with that of the wide band wireless base station 6, and the number of available free channels of the narrow band wireless base stations 2 and 3. I shall.

The narrow band wireless base stations 2 and 3 and the wide band wireless base station 6 are connected to the network 1 as shown in FIG.
And the narrow band wireless base stations 2 and 3 and the wide band wireless base station 6 communicate with each other via the network 1, so that the wide band wireless base station 6 can operate in a narrow band whose service areas overlap. It is possible to know the identification information of the wireless base stations 2 and 3 and the number of available free channels of the narrow band wireless base stations 2 and 3.

When the power of the terminal 9 is turned on by the user operating the operation unit 25, the broadband transmitter / receiver 24 first
Is turned on (step S30), and the broadcast information broadcast by the broadband wireless base station 6 is received (step S30).
31).

Based on the received broadcast information, the terminal 9 selects the narrow band wireless base station having the largest number of free channels (step S32). Here, the narrow band wireless base station 2
It is assumed that the number of available channels is the largest.

When the narrow band wireless base station can be selected (in this case, the narrow band wireless base station 2), the function of the narrow band transceiver 23 is turned on (step S33), and the narrow band wireless base station 2 is selected.
The communication request message is transmitted to the wireless LAN, but at that time, the message includes the identification information of the broadband wireless base station stored in step S7 (step S3).
4).

When the narrow band wireless base station 2 receives the communication request message from the terminal 9, the narrow band wireless base station 6 uses the identification information of the wide band wireless base station 6 contained in the message.
Then, call setting is performed (step S35). That is,
The broadband wireless base station 6 controls the terminal 9 to allocate a downlink broadband wireless channel. Further, an empty channel (empty slot) is assigned to the terminal 9 that has made the communication request (step S36). After that, terminal 9
Starts communication with the narrow band wireless base station 2 and the wide band wireless base station 6.

In FIG. 6, the narrow band transceiver 2
3. On / off of the function of the wideband receiver 24 may be performed by the user operating the operation unit 25 or by the control of the control unit 26.

The function of the narrow band transceiver 23 may be turned on when the user operates the operation unit 25 and the power is turned on. As described above, according to the second embodiment described above, the terminal 9 includes the narrowband radio whose service area overlaps with that of the broadband radio base station 6 included in the broadcast information from the broadband radio base station 6. The narrow band wireless base station having the largest number of free channels is selected based on the number of available free channels of the base stations 2 and 3, and the selected wireless base station and wide band wireless base station are the terminal 9 wireless channel. Even if the terminal 9 exists in an area where the service areas of a plurality of narrow band wireless base stations overlap by allocating the bidirectional narrow band wireless channel and the downlink wide band wireless channel in accordance with the allocation request, the terminal 9 can be easily operated. In addition, it is possible to find a base station with which communication can be reliably performed. Therefore, it is possible to prevent the concentration of traffic on a certain narrow band radio base station and the deterioration of the service quality of voice communication due to the concentration of traffic.

Further, comparing the selection processing time of the narrow band wireless base station in each of the first embodiment and the second embodiment, the control unit 26 only receives the broadcast information from the wide band wireless base station 6. The processing time is shorter in the second embodiment in which the narrow band wireless base station can be selected (see FIGS. 4 and 6).

[0049]

EFFECTS OF THE INVENTION A terminal existing in an overlapping area of service areas of a plurality of radio base stations can easily and reliably search for a radio base station with which communication can be performed, and the traffic is concentrated on one radio base station. And, it is possible to prevent the deterioration of the service quality of the voice call.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an overall configuration of a communication system according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a configuration of a wireless communication terminal.

FIG. 3 is a diagram showing a storage example of a table referred to when a control unit of a wireless communication terminal selects a narrowband wireless base station.

FIG. 4 is a diagram for explaining an operation of assigning a wireless channel to a wireless communication terminal in the communication system of FIG.

FIG. 5 is a flowchart for explaining a narrowband wireless base station selection processing operation in the wireless communication terminal.

6 is a diagram for explaining another operation of assigning a wireless channel to a wireless communication terminal in the communication system of FIG.

[Explanation of symbols]

1 ... Network 2, 3 ... Narrow band wireless base station, 4,
5, 6 ... Broadband wireless base station, 7 ... Server, 9 ... Wireless communication terminal (terminal), 21, 22 ... Antenna, 23 ... Narrowband transceiver, 24 ... Wideband receiver, 25 ... Operation part, 26 ... Control part , 27 ... table, 28 ... input / output unit.

Claims (3)

[Claims] 1. A radio channel allocation method in which one of a plurality of radio base stations allocates a radio channel to a terminal within its service area, wherein each of the plurality of radio base stations includes at least identification information of its own station and Broadcast information including the number of vacant wireless channels that can be communicated to the terminal through a predetermined wireless channel, the terminal receives a wireless channel that broadcasts the broadcast information, and the reception strength level and the Select a communicable radio base station from the plurality of radio base stations based on the number of free radio channels included in the broadcast information, and the selected radio base station responds to a radio channel allocation request from the terminal. A wireless channel allocating method, characterized by allocating a wireless channel. 2. A plurality of narrow band wireless base stations that provide bidirectional wireless channels and a wideband wireless base station that provides a downlink wideband wireless channel having a wider bandwidth than the bidirectional wireless channels so that they can communicate with each other. Connected, one of the plurality of narrowband radio base stations assigning a bidirectional radio channel to terminals within its coverage area,
In a radio channel allocation method in which the broadband radio base station allocates the downlink broadband radio channel to the terminals within its service area, each of the plurality of narrowband radio base stations is capable of at least identification information of its own station and communication. Broadcast the broadcast information including the number of idle radio channels to the terminal through a predetermined radio channel, the terminal receives the radio channel that broadcasts the broadcast information, and receives from the plurality of narrowband radio base stations. The reception strength level of the received wireless channel is a predetermined value or more, and the narrow band wireless base station having the maximum number of empty channels included in the broadcast information is preferentially selected, and the selected narrow band wireless base station and the The wideband radio base station is configured to receive the bidirectional radio channel and the downlink wideband radio channel in response to a radio channel allocation request from the terminal. A method of allocating radio channels, characterized in that 3. A plurality of narrowband wireless base stations providing bidirectional wireless channels and a wideband wireless base station providing a downlink wideband wireless channel having a wider bandwidth than the bidirectional wireless channels are able to communicate with each other. Connected, one of the plurality of narrowband radio base stations assigning a bidirectional radio channel to terminals within its coverage area,
In the wireless channel allocation method, wherein the broadband wireless base station allocates the downlink broadband wireless channel to the terminals in its service area, the broadband wireless base station is at least identification information of its own station,
And identification information of the narrow band base station having a service area overlapping with that of the wide band radio base station obtained by communication with the plurality of narrow band radio base stations, and a communicable space of the narrow band radio base station. A narrow band radio capable of communicating from the plurality of narrow band radio base stations based on the number of free radio channels included in the received broadcast information, the broadcast information including the number of wireless channels being broadcast to the terminal. A base station is selected, and the selected narrowband wireless base station and the wideband wireless base station allocate the bidirectional wireless channel and the downlink wideband wireless channel respectively in response to a wireless channel allocation request from the terminal. A wireless channel allocation method characterized by the above.