JPH09205669A - Radio packet communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the hit time due to channel changeover during excellent communication by preventing mis-start of hand-over processing in radio packet communication. SOLUTION: A base station 1-1 sets a packet channel being a radio channel used for packet communication to a radio terminal equipment 1-2 under its control and sets a packet channel exclusive block in response to a packet incidence pattern and sends intermittently a notice signal to the radio terminal equipment under its control and sends continuously an outgoing packet signal in the packet channel exclusive block to a radio terminal equipment during communication. On the other hand, the radio terminal equipment 1-2 uses the outgoing packet signal during packet channel exclusive block setting or uses a notice signal while the packet channel exclusive block is not set to discriminate whether or not itself is moved from a radio cell making communication at present and makes hand-over in the case that the discrimination result indicates the movement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to handover control and interference avoidance in a wireless packet communication method for exchanging data packets between a base station and a mobile wireless terminal.

[0002]

[Prior art]

-Prior Art 1: About PHS In so-called PHS (Personal Handy-phone System), autonomous distributed DCA (dynamic channel allocation) is adopted. If it is determined to be movement (during movement determination), handover control is performed, and if it is determined to be interference (during interference determination) Requests the base station to switch channels.

In handover control, a wireless terminal receives a control signal periodically transmitted from a plurality of base stations in the vicinity, and a base station whose reception level is a threshold value (hereinafter, standby permission level) or higher is a handover destination base station. This is done by restarting communication at this handover destination base station.
When all the reception levels of the control signal are lower than the standby permission level, the handover destination base station cannot be selected, resulting in “handover failure”. At this time, communication is restarted at the handover source base station.

When the frame error rate of the downlink communication signal is equal to or higher than the threshold value and the reception level is equal to or higher than the threshold value, the radio terminal determines that interference has occurred and transmits a channel switching request signal to the base station to request channel switching. To do. The base station switches channels immediately after receiving the channel switching request signal.
When channel switching is not performed even after a certain period of time, the wireless terminal determines that a channel error has occurred in the channel switching request signal and retransmits the channel switching request signal. The wireless terminal, when the number of retransmissions of the channel switching request signal exceeds a threshold value, suspends the transmission of the channel switching request signal for a certain period of time, measures the reception status of the downlink communication signal, and detects the interference again, the channel A switching request signal is transmitted to request channel switching (for details, refer to "2nd Generation Cordless Telephone System Standard 1st Edition" RCR, STD-28,
reference).

Prior Art 2: About CDPD CDPD that provides wireless packet communication in the United States
In (Cellular Digital Packet Data), FCA (Fixed Channel Assignment) is adopted. Also, since the wireless channel is shared with the circuit switched communication, the base station switches the channel of the packet channel at a fixed cycle or at an arbitrary timing. In CDPD, wireless terminals
When the reception quality of the downlink signal deteriorates, it is not determined whether the deterioration is caused by movement from the serving cell or by the base station switching the channel. Further, since FCA is adopted, the wireless terminal has no means for requesting channel switching to avoid interference.

In CDPD, a base station continuously transmits a downlink packet signal on a packet channel, and a wireless terminal in communication continuously receives the downlink signal. When the wireless terminal in communication cannot receive the downlink packet signal, it determines that the packet channel is not set on the currently received wireless channel, and is assigned to the wireless cell that was performing packet communication until immediately before. Receive wireless channels sequentially. When the downlink packet signal is received in this reception, the wireless terminal restarts the packet communication. This operation corresponds to channel switching.

On the other hand, when the downlink packet signal is not received on all the radio channels assigned to the radio cell which has been performing packet communication until immediately before, the radio terminal determines that the radio terminal is assigned to the radio cell assigned to the adjacent cell. Receive channels sequentially. When the downlink packet signal is received in this reception, the wireless terminal restarts the packet communication. This operation is equivalent to handover (see "Cellul" for details).
ar Digital Packet Data System Specification Releas
e 1.0 ”, issued by CDPD Industry Imput Coordinator, see).

-Prior Art 3: Tele-terminal In the tele-terminal that provides wireless packet communication in Japan, FCA (fixed channel allocation) is adopted. In the teleterminal, the radio channel is not shared with the circuit switching communication like the CDPD, and therefore the base station does not switch the channel. Further, since FCA is adopted, the wireless terminal has no means for requesting channel switching to avoid interference.

In the teleterminal, the base station continuously transmits the downlink signal in the packet channel, and the wireless terminal in communication continuously transmits the downlink signal. When the reception level of the downlink signal is less than the threshold value, the wireless terminal determines that the reception quality has deteriorated due to movement from the serving cell and performs handover control (“Radio equipment of wireless base station for land mobile wireless data communication”). RCR, STD-6, see).

[0010]

In a wireless packet communication in which a base station sets a packet channel dedicated section according to a packet occurrence pattern, and downlink packet signals are continuously transmitted only in the packet channel dedicated section, during communication. When the packet channel dedicated section is not set (when not set), the wireless terminal of 1 cannot continuously receive the downlink packet signal. Therefore, when the above-mentioned conventional technique 1 is applied, since the wireless terminal cannot receive the downlink packet signal when the packet channel dedicated section is not set, the handover is erroneously activated even when the wireless terminal is in the service area. The problem arises that

In addition, each base station autonomously searches for an empty channel from all the channels allocated to the communication system and uses an autonomous distributed DCA to allocate communication to the base station. In the communication system, a channel without interference is assigned at the start of communication, but a situation may occur in which co-channel interference is caused by communication of surrounding cells due to movement of a wireless terminal or the like.

In the prior art 1, the wireless terminal avoids interference only by switching channels. When Prior Art 1 is applied to point-multipoint wireless packet communication in which one base station communicates with a plurality of wireless terminals using a common channel, one wireless terminal continuously detects interference. At times, the base station needs to activate channel switching to avoid interference even when other wireless terminals are performing good communication without interference. As a result, not only the wireless terminal that has detected the interference but also all the wireless terminals belonging to the same cell switch the channels, so that even during good communication, a momentary interruption of the communication due to the channel switching occurs.

In point / multipoint communication,
Since interference detection is performed at multiple geographically dispersed points, one channel is compared to point-point type circuit switching communication in which one base station and one wireless terminal communicate with each other through a dedicated channel. There is a problem in that the number of starting channel switching increases and instantaneous interruption due to channel switching increases.

Further, when the prior art 2 is applied, since the wireless terminal in communication cannot receive the downlink signal when the packet channel dedicated section is not set, the wireless terminal is not moving from the serving cell or the base station. Even if the channel switching is not performed, there is a problem that the process of erroneously receiving the wireless channels is activated. Furthermore, it is not assumed that the wireless terminal will be interfered with.

Further, when the prior art 3 is applied, since the wireless terminal in communication cannot receive the downlink signal when the dedicated section for the packet channel is not set, even if the wireless terminal is not moving from the serving cell, it is erroneous. The problem arises that a handover is triggered. Further, as in the case of the related art 2, a situation in which the wireless terminal receives interference is not assumed.

Therefore, an object of the present invention is to provide a wireless packet communication method that solves or reduces the above problems in wireless packet communication based on autonomous distributed DCA. Then, in order to achieve the above object, in the wireless packet communication in which the base station intermittently sets the packet channel dedicated section according to the occurrence pattern of the packet,
A first object of the present invention is to realize a handover control method capable of preventing a wireless terminal from erroneously initiating a handover process. A second object is to realize an interference avoiding method that can avoid and control the number of activations of channel switching to control the instantaneous interruption time due to channel switching during favorable communication.

[0017]

According to the first aspect of the present invention,
Wireless packet communication method for performing packet communication using a packet channel between a plurality of base stations connected to a packet network and a plurality of wireless terminals located in a wireless cell that is a communication area under the plurality of base stations That is, each of the base stations sets a communication line with a wireless terminal under the control using a plurality of wireless channels, and sets a packet channel which is a wireless channel used for packet communication among the plurality of wireless channels. It is set commonly to wireless terminals under its control, and a packet channel dedicated section, which is a section for allocating the packet channel for packet communication, is intermittently set according to the occurrence pattern of packets with each of the wireless terminals, The broadcast signal is intermittently transmitted to all wireless terminals of the Packet signal is continuously transmitted, and each of the wireless terminals is currently performing communication by using the downlink packet signal during the packet channel dedicated section setting, and by using the annunciation signal when the packet channel dedicated section is not set. Determine if you have moved from the wireless cell,
If the determination result indicates that the mobile terminal has moved, a handover is performed.

According to a second aspect of the present invention, in the first aspect of the invention, each of the wireless terminals continuously receives (1) a predetermined time when the dedicated section for the packet channel is set. The error rate and average received power of the downlink packet signal are measured, and (2) the error rate is equal to or greater than a preset threshold A (where A is a real number), and
If the average received power is less than the threshold B (B is a real number), it is determined that the mobile station itself has moved from the serving cell, which is the radio cell of the base station currently under its control, and handover processing is performed. When the packet channel dedicated section is not activated, (3) the notification signal transmitted intermittently is received for a predetermined time set in advance, and a reception error is continuously detected N1 times (where N1 is a natural number) in the reception. When I did
Alternatively, when the average received power is less than the threshold C (where C is a real number) consecutively N2 (where N2 is a natural number) times, it is determined that the mobile device itself has moved from the serving cell and the handover process is activated. Is characterized by.

According to a third aspect of the present invention, a packet channel is provided between a plurality of base stations connected to a packet network and a plurality of wireless terminals located within a wireless cell which is a communication area under the plurality of base stations. Is a wireless packet communication method for performing packet communication using the base station, wherein each base station uses a plurality of wireless channels to set a communication line with a wireless terminal under the control of the plurality of wireless channels. A packet is a section in which a packet channel, which is a wireless channel used for communication, is set commonly to subordinate wireless terminals, and the packet channel is allocated for packet communication according to the occurrence pattern of packets with each of the wireless terminals. A dedicated channel section is set intermittently, and downlink packet signals are transmitted to the wireless terminals under communication within the dedicated packet channel section. And each of the wireless terminals detects interference between adjacent cells using the downlink packet signal, and when detecting the interference, (1) transmits a channel switching request signal to the corresponding base station, and (2) After transmitting the channel switching request signal, the channel switching is not executed even after a certain period of time,
In addition, when the interference is continuously detected, the channel switching request signal is retransmitted, (3) When the interference is recovered, the channel switching request is terminated, and (4) the channel switching request signal is retransmitted. The number of retransmissions, which is the number of times
(5) When the channel switching request signal is transmitted with the number of retransmissions added, each of the base stations (6) is setting a data link in another wireless cell under its control. No wireless terminal exists, or when there is another wireless terminal in the data link setting and the number of retransmissions is equal to or more than the threshold M2 (M2 is a natural number), channel switching is executed, and (7) a wireless cell under its control. If there is another wireless terminal in the data link setting within the area and the number of retransmissions is less than the threshold M2, channel switching is not performed, and each wireless terminal (8) has the number of retransmissions equal to the threshold M1.
(However, M1 is a natural number such that M1 <M2), and
If channel switching is not performed and interference is continuously detected, handover is performed, and (9)
When the handover is successful, the interference is avoided by communicating with the handover destination base station, and (10) when the handover is unsuccessful, the channel switching request signal is retransmitted to request channel switching. Is characterized by.

As described above, according to the present invention, when the wireless terminal in communication is not set to the packet channel dedicated section, the movement of the wireless terminal is determined based on the reception status of the broadcast signal. Also, it becomes possible to activate handover when moving from the serving cell. In other words, it is possible to prevent a malfunction that erroneously activates the handover processing when the dedicated section for the packet channel is not set as in the related art (claims 1 and 2).

Further, when the wireless terminal is located in a place where adjacent cells overlap and the base station does not switch the channel even if a channel switching is requested to avoid interference, the wireless terminal is Interference avoidance is realized by activating the handover process.

Further, the base station suspends channel switching until the number of retransmissions of the channel switching request signal becomes equal to or more than the threshold value M2 when there is another wireless terminal in communication in the wireless cell under the control of the base station, and the number of retransmissions reaches the threshold value. Since channel switching is executed only when interference is continuously detected until M2 or more, and channel switching is not executed when the wireless terminal succeeds in handover before the number of retransmissions becomes M2 or more,
The number of times channel switching is activated is suppressed (claim 3).

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) First Embodiment FIG. 1 is a diagram showing a configuration of a communication system to which a wireless packet communication method according to a first embodiment of the present invention is applied. As shown in the figure, this communication system is composed of a plurality of cells 1-3 in the service area of wireless packet communication, and a plurality of base stations 1-1 provided in each cell perform packet communication. It accommodates the wireless terminal 1-2.

By the way, there are a plurality of communication channels to which packet signals are transferred and a plurality of control channels to which control signals are transferred to the channels in which wireless packet communication can be used.
There are types. A plurality of communication channels are shared among cells and are assigned to each cell by dynamic channel assignment. Here, the base station selects an arbitrary channel from a plurality of communication channels and measures the presence or absence of a signal.If the measured channel is an empty communication channel, this channel is set between the base station and the wireless terminals under its control. Autonomous decentralized dynamic channel allocation is performed for each packet channel. The data packet transfer between the base station and the wireless terminal under the control is performed by using packet multiplexing on a common packet channel. On the other hand, a plurality of control channels are fixedly assigned in advance to each base station so that interference between adjacent cells does not occur.

Next, the setting of the packet channel dedicated section will be described. FIG. 2 is a time chart showing how the packet channel dedicated section is set in the first embodiment. As shown in the figure, the base station periodically broadcasts the candidate channel information by the broadcast signal 2-3 of the control channel. The wireless terminals (here, wireless terminals A and B)
The broadcast signal is periodically received, the candidate channel information is stored in the memory in the wireless terminal, and the packet is transmitted on the candidate channel.

When the base station receives a downlink data transmission request from the base station to the radio terminal or an uplink data packet 2-2 from the radio terminal to the base station, the base station receives a setting notification signal 2-5 on the candidate channel. To set the packet channel dedicated section 2-4. In the packet channel, the base station continuously transmits packet signals. When there is downlink transmission data, the base station stores the data in the packet signal. The base station has a timer for measuring the continuous non-transmission time of packets, and resets and restarts the timer when transmitting and receiving packets. The base station, when the value of the timer exceeds a value representing a predetermined time,
The release notification signal 2-6 is transmitted to release the packet channel dedicated section 2-4. According to this control, the packet channel dedicated section is continuously set when packet transfer is frequently performed, and the packet channel dedicated section is released when there is no packet transfer for a certain period. It is possible to set the dedicated section for the packet channel.

Here, FIG. 3 shows a state transition diagram of the wireless terminal corresponding to this control. As shown in the figure, the wireless terminal in communication receives the control channel and the candidate channel broadcast by the broadcast signal. When the wireless terminal receives a broadcast signal indicating that the packet channel dedicated section is being set (the packet channel dedicated section is being set) or receives the setting notification signal on the candidate channel, the packet channel dedicated section is When it is determined that the packet has been set, movement determination from the serving cell is performed based on the reception status of the packet signal.
In addition, when the wireless terminal receives a broadcast signal indicating that the packet channel dedicated section has not been set (packet channel dedicated section has not been set), or when it has received a release notification signal on a candidate channel, the packet channel dedicated It is determined that the section has not been set, and movement determination from the serving cell is performed based on the reception status of the notification signal.

Next, FIG. 4 shows a flowchart for activating the handover process of the wireless terminal during the setting of the packet channel dedicated section. Step SA1 in the same figure
As indicated by SA4, the wireless terminal measures the error rate and the average received power of the packet signals that are continuously received, and when the error rate is equal to or greater than the threshold value A and the average received power is less than the threshold value B,
It judges that it has moved from the serving cell and activates the handover process.

Further, FIG. 5 shows a flow chart of activation of the handover processing when the packet channel dedicated section of the wireless terminal is not set. Step SB1 in FIG.
As indicated by SB4, the wireless terminal periodically receives the notification signal and the reception power (average reception power) is less than the threshold value C when the reception error occurs only consecutive N1 times or consecutive N2 times. At this time, it judges that it has moved from the serving cell and activates the handover process. Note that N
1 and N2 are preset natural numbers.

(2) Second Embodiment FIG. 6 is a diagram showing the configuration of a communication system to which the wireless packet communication method according to the second embodiment of the present invention is applied. As shown in the figure, this communication system is composed of a plurality of cells 1-3 in the service area of wireless packet communication, and a plurality of base stations 1-1 provided in each cell perform packet communication. It accommodates the wireless terminal 1-2. In this communication system, since the wireless terminals are geographically dispersed, only one wireless terminal may be interfered with, and other wireless terminals may be in good communication.

As described in the first embodiment, there are two types of channels that can be used for wireless packet communication: a plurality of communication channels for transferring packet signals and a plurality of control channels for transferring control signals. . Also, a plurality of communication channels are shared between cells and are assigned to each cell by dynamic channel assignment. Here, the base station selects an arbitrary channel from a plurality of communication channels and measures the presence or absence of a signal.If the measured channel is an empty communication channel, this channel is set between the base station and the wireless terminals under its control. Autonomous decentralized dynamic channel allocation is performed for each packet channel. Further, the transfer of the data packet between the base station and the wireless terminal under the control is performed by using packet multiplexing on the common packet channel. Moreover, a plurality of control channels are fixedly assigned to each base station in advance so that interference between adjacent cells does not occur.

FIG. 7 is a flowchart showing the flow of interference avoidance control in the wireless terminal used in the second embodiment. The interference avoidance control in this system will be described below with reference to FIG. 7. Unless otherwise specified, the main body of the operation in the following description with reference to FIG. 7 is
It is assumed to be a front-end terminal.

The wireless terminal first measures the presence or absence of interference on the packet channel. When detecting interference, the wireless terminal adds the number of retransmissions to the channel switching request signal and transmits it to the base station via the control channel (step SC2). At this time, the number of retransmissions is the value set in step SC1,
That is, it is zero. After the channel switching request signal is transmitted, when the channel switching instruction signal is received on the control channel within the fixed period T, the channel is switched to the channel instructed by the channel switching instruction signal (steps SC3, SC4, S).
C11).

After the channel switch request signal is transmitted, if the channel switch instruction signal is not received within a certain period of time T, the interference on the assigned communication channel is measured (steps SC3, SC4, SC5). Then, when the number of retransmissions is less than the threshold M1 when interference is detected, the number of retransmissions in the channel switching request signal is increased by 1 and retransmitted to the base station (steps SC7, SC8, SC1).
2).

In step SC8, if the number of retransmissions is equal to or larger than the threshold M1, the handover process is activated.
When the wireless terminal exists in the area where the service areas of the adjacent cells overlap, the wireless terminal succeeds in the handover to the adjacent cell and restarts the packet communication in the handover destination cell (SC9, SC10). In step SC10, when there is no wireless terminal in the area where the service areas of the adjacent cells overlap, handover cannot be performed. Therefore, the number of retransmissions in the channel switching request signal is increased by 1 and retransmission is performed (step SC1).
2). If no interference is detected in step SC7, the channel switching request signal is not retransmitted and communication is continued on the assigned communication channel. Note that, hereinafter, various explanations will be given assuming that the threshold value M1 is 1.

FIG. 8 is a flow chart showing the flow of channel switching activation determination control at the time of receiving a channel switching request signal in the base station used in the second embodiment. Hereinafter, the channel switching activation determination control in this system will be described with reference to FIG. In addition, unless otherwise stated, the main body of the operation in the following description with reference to FIG. 8 is
It shall be a base station.

As shown in FIG. 8, the base station determines whether or not there is another wireless terminal setting up a data link (step SD1). Start switching (step SD3)
SD4, SD5). In step SD1, when there is another wireless terminal that has established a data link, the number of retransmissions in the channel switching request signal is evaluated (step S
D2) If the number of retransmissions is equal to or greater than the threshold M2, channel switching is activated (steps SD3, SD4, SD5). If the number of retransmissions is less than the threshold M2 in step SD2, channel switching is not activated. In addition, the threshold value M2 is set to 2 here, and various description is given below based on this premise. However, it is assumed that M1 <M2.

FIG. 9 is a processing diagram showing a control sequence when one of the two wireless terminals (wireless terminal A) in the data link setting in the second embodiment detects interference. The control sequence at the time of interference in this system will be described below with reference to FIG. As shown in FIG. 9, the wireless terminal A that has detected interference receives the channel switching request signal 9-1.
Is transmitted to the base station (step SE1). The base station that has received the channel switching request signal 9-1 from the wireless terminal A
Since there are other wireless terminals in the data link setting, the number of retransmissions in the channel switching request signal is evaluated (steps SF1 and SF2). Here, the number of retransmissions is 0, which is less than the threshold value M2, so the base station does not activate channel switching (step SF3).

As a result, since the wireless terminal A does not receive the channel switching instruction signal even after the elapse of the fixed time T, the interference measurement is performed again, and when the interference is detected by this measurement, the number of retransmissions is evaluated. Here, since the number of retransmissions is 0 and is less than the threshold M1, the number of retransmissions is increased by 1 and the channel switching request signal is retransmitted (steps SE2 to S2).
E7).

Channel switching request signal 9 from wireless terminal A
The base station that has received -1 again evaluates the number of retransmissions in the channel switching request signal because there are other wireless terminals in the data link setting (steps SF4 and SF5). Here, since the number of retransmissions is 1 and is less than the threshold value M2, the base station does not activate channel switching (step SF6). As a result, since the wireless terminal A does not receive the channel switching instruction signal even after the elapse of the fixed time T, the interference measurement is performed again,
When interference is detected by this measurement, the number of retransmissions is evaluated (steps SE8 to SE12). Here, since the number of retransmissions is 1, which is equal to or greater than the threshold M1, the wireless terminal A activates the handover process (step SE13).
If the wireless terminal A exists in the area where the service areas of the adjacent cells overlap, the handover succeeds, so the wireless terminal A restarts the packet communication in the handover destination cell (steps SE14 and SE1).
5).

In step SE14, if the wireless terminal does not exist in the area where the service areas of the adjacent cells overlap, handover cannot be performed. Therefore, the number of retransmissions is increased by 1 and the channel switching request signal is retransmitted (step SE17). . Note that the base station that has received the channel switching request signal evaluates the number of retransmissions in the channel switching request signal because there is another wireless terminal in the data link setting. Since the number of retransmissions is equal to or greater than the threshold M2,
The base station will initiate channel switching.

[0042]

As described in detail above, in the present invention,
In wireless packet communication in which a base station intermittently sets a packet channel dedicated section according to a packet occurrence pattern based on autonomous distributed DCA, it is possible to prevent a wireless terminal from erroneously activating a handover process. . More specifically, since the wireless terminal in communication does not make a determination based on the reception status of the downlink signal of the packet channel when the packet channel dedicated section is not set, erroneous activation of handover is prevented. Further, when the dedicated section for the packet channel is not set, the determination is made based on the reception status of the broadcast signal, so that it is possible to activate the handover processing without waste when moving from the serving cell.

Further, in the wireless packet communication based on the autonomous distributed DCA, the number of activations of channel switching can be suppressed, and the instantaneous interruption time due to channel switching during good communication can be suppressed. More specifically, when the wireless terminal requests channel switching to avoid interference and the base station does not perform channel switching, the wireless terminal activates the handover process, causing adjacent cells to overlap. If the wireless terminal is located at a certain position, it is possible to avoid interference by handover. Also, when there is another wireless terminal in communication in the communication cell under the control of the base station, the base station suspends channel switching until the number of times of retransmission of the channel switching request signal becomes equal to or more than the threshold value M2. Therefore, in this case, channel switching is performed only when interference is continuously detected until the number of retransmissions reaches the threshold M2 or more. When the wireless terminal succeeds in the handover before the number of times of retransmission reaches the threshold value M2 or more, channel switching is not performed, so that it is possible to suppress the number of activations of channel switching.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a communication system to which a wireless packet communication method according to a first embodiment of the present invention is applied.

FIG. 2 is a time chart showing how a packet channel dedicated section is set in the same embodiment.

FIG. 3 is a state transition diagram of the wireless terminal corresponding to the control shown in FIG.

FIG. 4 is a flowchart of activation of a handover process of a wireless terminal during setting of a packet channel dedicated section according to the first embodiment of the present invention.

FIG. 5 is a flowchart of activation of a handover process when a packet channel dedicated section of the wireless terminal is not set in the embodiment.

FIG. 6 is a diagram showing a configuration of a communication system to which a wireless packet communication method according to a second embodiment of the present invention is applied.

FIG. 7 is a flowchart showing a flow of interference avoidance control in the wireless terminal used in the same embodiment.

FIG. 8 is a flowchart showing a flow of channel switching activation determination control at the time of receiving a channel switching request signal in the base station used in the embodiment.

FIG. 9 is a processing diagram showing a control sequence when one of the two wireless terminals (wireless terminal A) in the data link setting in the embodiment detects interference.

[Explanation of symbols]

1-1 ... base station, 1-2 ... wireless terminal, 1-3 ... wireless cell, 2-1 ... packet signal, 2-2 ... data packet signal 2-3 ... broadcast signal, 2 -4 ... Packet channel dedicated section, 2-5 ... Setting notification signal, 2-6 ...
... Release notification signal, 6-1 ... base station, 6-2 ... wireless terminal, 6-3 ... wireless cell, 9-1 ... channel switching request signal.

Claims (3)

[Claims] 1. Packet communication is performed using a packet channel between a plurality of base stations connected to a packet network and a plurality of wireless terminals located in a wireless cell which is a communication area under the plurality of base stations. A wireless packet communication method for performing, wherein each base station sets a communication line with a wireless terminal under control using a plurality of wireless channels, and a wireless channel used for packet communication among the plurality of wireless channels. Is commonly set to subordinate wireless terminals, and a packet channel dedicated section, which is a section for allocating the packet channel for packet communication according to the occurrence pattern of packets with each of the wireless terminals, is intermittent. , The broadcast signal is intermittently transmitted to all the wireless terminals under its control, and the packet channel dedicated section is sent to the wireless terminals under the control of communication. In which the downlink packet signal is continuously transmitted, and each of the wireless terminals is currently performing communication using the downlink packet signal during the packet channel dedicated section setting, and the broadcast signal when the packet channel dedicated section is not set. A wireless packet communication method characterized by determining whether or not the wireless cell itself has moved from the existing wireless cell, and performing handover if the determination result indicates that the wireless cell has moved. 2. Each of the wireless terminals, when setting the packet channel dedicated section, (1) measures an error rate and an average received power of the downlink packet signal continuously received for a preset fixed time. (2) If the error rate is equal to or greater than a preset threshold value A (where A is a real number) and the average received power is less than the threshold value B (where B is a real number), It is judged that the mobile station itself has moved from the serving cell, which is the wireless cell of the base station, and the handover process is started, and when the packet channel dedicated section is not set, (3) the intermittent operation is performed for a preset period of time. When the transmitted notification signal is received and a reception error is detected N1 (where N1 is a natural number) consecutively in the reception, or when the average received power is N2 (where N2 is a natural number) consecutively, the threshold value C ( However, when C is less than a real number), the wireless packet communication method according to claim 1, wherein the handover processing is started by determining that the terminal itself has moved from the serving cell. 3. A packet communication using a packet channel between a plurality of base stations connected to a packet network and a plurality of wireless terminals located in a wireless cell which is a communication area under the plurality of base stations. A wireless packet communication method for performing, wherein each base station sets a communication line with a wireless terminal under control using a plurality of wireless channels, and a wireless channel used for packet communication among the plurality of wireless channels. Is commonly set to subordinate wireless terminals, and a packet channel dedicated section, which is a section for allocating the packet channel for packet communication according to the occurrence pattern of packets with each of the wireless terminals, is intermittent. Set to, the downlink packet signal is continuously transmitted in the dedicated section of the packet channel to the wireless terminal under communication, At the end, interference between adjacent cells is detected using the downlink packet signal, and when the interference is detected, (1) the channel switching request signal is transmitted to the corresponding base station, and (2) the channel switching request signal is transmitted. After that, the channel switching is not executed even after a certain period of time, and when the detection of the interference is continued, the channel switching request signal is retransmitted,
(3) When interference is recovered, the channel switching request is terminated, (4) the number of retransmissions, which is the number of times the channel switching request signal is retransmitted, is stored, and (5) the number of retransmissions is included in the channel switching request signal. When each base station receives the channel switching request signal, (6) when there is no other wireless terminal in the data link setting in the wireless cell under its control, or There is a wireless terminal for which a data link is being set, and the number of retransmissions is the threshold M2
When 2 is a natural number or more, channel switching is executed,
(7) There is another wireless terminal for which a data link is being set within the wireless cell under its control, and the number of retransmissions is the threshold M2.
If the number of times of transmission is less than the threshold, the channel switching is not performed, and (8) the number of retransmissions is set to the threshold value M1 (where M1 is M
1 <M2, a natural number or more), and if the channel is not switched and the interference is continuously detected, the handover is performed, and (9) if the handover is successful, the hand is performed. A radio packet communication method characterized in that interference is avoided by communicating with an overdestination base station, and (10) when handover fails, the channel switching request signal is retransmitted to request channel switching.