JP2004336455A - Access control method, relay terminal and mobile terminal for radio multihop network, - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an access control method, an apparatus and a program for a radio multihop network which realize indirect communication between a base station and a mobile terminal by another terminal's relaying when the base station and the mobile terminal can not communicate with each other directly. <P>SOLUTION: The access control method has a first step where the mobile terminal transmits an access request including an available individual access channel number to the base station via a common access channel; a second step where a relay terminal monitors the access request and, when there is no access response from the base station to the access request, transmits an accessibility notification to the mobile terminal via an individual access channel corresponding to the number; and a third step where the mobile station transmits accessibility confirmation to the relay terminal via the individual channel. The mobile terminal and the relay terminal communicate with each other via the individual access channel, while the relay terminal and the base station communicate with each other via the common access channel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an access control method for a wireless multi-hop network that enables communication between a mobile terminal and a base station via a relay terminal when the mobile terminal cannot communicate with the base station via a common access channel. The present invention relates to a terminal and a relay terminal.
[0002]
[Prior art]
According to a conventional mobile communication system such as CDMA2000 (Code Division Multiple Access-2000), it is assumed that a mobile terminal directly communicates with a base station. When newly trying to communicate with the base station, the mobile terminal transmits an access request to the base station using an uplink access channel (ACH). On the other hand, the base station that permits communication transmits an access response to the mobile terminal using the downlink control channel. Thereby, the mobile terminal can communicate with the base station.
[0003]
FIG. 1 is a system configuration diagram of a conventional wireless network.
[0004]
According to FIG. 1, a base station (BS: Base Station) 1 covers a communication area 4, and a plurality of mobile terminals (MT: Mobile Terminal) 2 exist in the communication area 4. The mobile terminals MT-2 and MT-3 existing in the communication area 4 can directly communicate with the base station BS1 via the access channel. On the other hand, the mobile terminal MT-1 not existing in the communication area 4 cannot directly communicate with the base station BS1.
[0005]
Also, a conventional wireless multi-hop network is mainly a network in which a plurality of mobile terminals are connected via a wireless LAN, and when a communication source terminal and a communication destination terminal cannot directly communicate with each other, the other mobile terminal transmits its traffic Is relayed.
[0006]
[Non-patent document 1]
3GPP2 C.I. S0003-C, "Medium Access Control (MAC) Standard for cdma2000 Spread Spectrum Systems," 2002, [online], [May 8, 2003 search], Internet <URL: http: // www. 3gpp2. org / Public_html / specs / C. S0003-C_v1.0. pdf>
[0007]
[Problems to be solved by the invention]
As described above, the conventional mobile communication system is effective only when the mobile terminal can directly communicate with the base station. Therefore, it is necessary to arrange communication areas in a cell shape so as to cover all areas using a plurality of base stations BS. Thereby, when the mobile terminal 2 moves and enters the communication area of another base station BS, communication is continued by the handover procedure. On the other hand, when the base station BS does not exist at the handover destination, or when a signal from the base station BS does not reach inside a building or a tunnel, the mobile terminal 2 receives the control channel from the base station BS. Communication cannot be established.
[0008]
Therefore, the present invention provides an access control method, an apparatus, and a program for a wireless multi-hop network in which, when a base station and a mobile terminal cannot communicate directly, another terminal can perform indirect communication by relaying. Aim.
[0009]
[Means for Solving the Problems]
According to the access control method of the present invention,
A first step in which a mobile terminal transmits an access request including a number of available dedicated access channels to a base station via a common access channel;
A second step in which the relay terminal monitors the access request and transmits an accessible notification to the mobile terminal via the dedicated access channel corresponding to the number when there is no access response from the base station to the access request;
A third step in which the mobile terminal sends an access confirmation to the relay terminal via the dedicated access channel;
And the mobile terminal and the relay terminal communicate via a dedicated access channel, and the relay terminal and the base station communicate via a common access channel.
[0010]
According to another embodiment of the access control method of the present invention, in the second step, when an access request is received from a plurality of relay terminals, a relay terminal having the highest received signal level to noise signal level ratio is selected. It is also preferred.
[0011]
According to another embodiment of the access control method of the present invention, in the second step, the relay terminal preferably performs carrier sense and transmits an access enable notification to the mobile terminal.
[0012]
Further, according to another embodiment of the access control method of the present invention, for the first step, the access request preferably includes a number of a plurality of available individual access channels.
[0013]
Further, according to another embodiment of the access control method of the present invention, the access permission confirmation is monitored by another relay terminal, and a predetermined condition to deny use of the dedicated access channel for any other relay terminal is set. If so, the relay terminal further includes a fourth step of transmitting to the mobile terminal a stop request including the number of the dedicated access channel, and excluding the number of the dedicated access channel based on the stop request, It is also preferable to repeat from the step.
[0014]
Further, according to another embodiment of the access control method of the present invention, in the second step, the mobile terminal transmits the transmission power control means of its own mobile terminal to such an extent that it can receive an access response from at least one relay terminal. It is also preferable to control the transmission power.
[0015]
According to the relay terminal of the present invention,
Common access channel communication means including a number of available dedicated access channels and monitoring an access request transmitted from the mobile terminal to the base station via the common access channel;
Base station response detecting means for detecting that there is no access response from the base station to the access request;
Via an individual access channel corresponding to the number, an access notice to the mobile terminal, and via the individual access channel, an individual access channel communication means for receiving an access confirmation from the mobile terminal;
The mobile terminal and the relay terminal communicate with each other via a dedicated access channel, and the relay terminal and the base station have relay control means for controlling communication via a common access channel.
[0016]
According to another embodiment of the relay terminal of the present invention, the relay control means monitors the access permission confirmation, and, when a predetermined condition to refuse the use of the dedicated access channel is satisfied, the relay control means includes the number of the dedicated access channel. It is also preferable to send a suspension request to the mobile terminal.
[0017]
Further, according to another embodiment of the relay terminal of the present invention, it is preferable that the dedicated access channel communication unit performs carrier sense and transmits an access enable notification to the mobile terminal.
[0018]
According to the mobile terminal of the present invention,
Common access channel communication means for transmitting an access request including a number of available individual access channels to the base station via the common access channel;
Base station / relay terminal response detecting means for detecting that there is no access response from the base station in response to the access request, and that access permission notification has been made from the relay terminal;
When there is no access response from the base station, an individual access channel for receiving an access enable notification from the relay terminal via the individual access channel corresponding to the number and transmitting an access enable confirmation to the relay terminal via the individual access channel Communication means for communicating with the relay terminal via the dedicated access channel and indirectly with the base station.
[0019]
According to another embodiment of the mobile terminal of the present invention, when receiving an access request from a plurality of relay terminals, the mobile terminal further comprises a relay terminal selecting means for selecting a relay terminal having a highest received signal level to noise signal level ratio. It is also preferred.
[0020]
Furthermore, according to another embodiment of the mobile terminal of the present invention, it is also preferable that the common access channel communication means includes the number of a plurality of available individual access channels in the access request.
[0021]
Further, according to another embodiment of the mobile terminal of the present invention, when a use stop request including the number of the dedicated access channel is received from any of the relay terminals, the common access channel communication means includes the use stop request in the access request. It is also preferred to include the number of available dedicated access channels excluding the number of dedicated access channels based on the request.
[0022]
Further, according to another embodiment of the mobile terminal of the present invention, it is preferable that the mobile terminal further includes transmission power control means for controlling the transmission power of the mobile terminal to the extent that an access response can be received from at least one relay terminal.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 2 is a system configuration diagram of the wireless multi-hop network according to the present invention.
[0024]
According to FIG. 2, a plurality of relay terminals 3 exist in the communication area 4 of the base station 1. The relay terminals RT-1 and RT-2 can directly communicate with the base station 1 via the common access channel ACH1. First, the mobile terminal 2 attempts to connect to the base station 1 using the common access channel ACH1. According to FIG. 2, the mobile terminal 2 cannot communicate directly with the base station 1 because it is located outside the communication area 4. Accordingly, the mobile terminal 2 can indirectly communicate with the base station 1 by directly communicating with the relay terminal RT-1 via the dedicated access channel ACH2.
[0025]
The common access channel ACH1 is for communicating with the base station 1, and all the mobile terminals 2 existing in the communication area 4 can monitor the communication contents. The dedicated access channel ACH2 is for communicating with mobile terminals 2 other than the base station 1.
[0026]
FIG. 3 is a time slot diagram for elapse of time according to the present invention.
[0027]
The access channel is divided into a plurality of slots, the first slot is assigned to the common access channel ACH1, and the second slot is assigned to the dedicated access channel ACH2. Each slot is divided into a first half and a second half, and is assigned to a request signal and a response signal, respectively.
[0028]
(T1) The mobile terminal MT transmits an access request to the base station 1 using the first half of the common access channel ACH1 in the first slot. At this time, the channel number ACH2 of the dedicated access channel is transmitted together. This individual access channel ACH2 is monitored by all the relay terminals RT in the communication area (where radio waves reach) of the mobile terminal MT. It is preferable that the numbers of the plurality of individual access channels are included in the access request.
(T2) In response to T1, the base station BS transmits an access response to the mobile terminal MT using the latter half of the common access channel ACH1 in the first slot. Thereby, the mobile terminal MT can directly communicate with the base station BS. The access response is monitored by all the relay terminals RT in the communication area.
(T3) Thereafter, the standby time is reached.
[0029]
(T4) The mobile terminal MT transmits an access request to the base station 1 using the first half of the common access channel ACH1 in the first slot. At this time, the channel number ACH2 of the dedicated access channel is transmitted together. This individual access channel ACH2 is monitored by all the relay terminals RT in the communication area (where radio waves reach) of the mobile terminal MT.
(T5) At this time, it is assumed that the base station BS has not responded to T1. This non-response is also monitored by all the relay terminals RT in the communication area of the mobile terminal MT (where radio waves reach). Thereby, the mobile terminal MT determines that the connection with the base station BS using the common access channel ACH1 has failed, and tries to connect with the relay terminal using the dedicated access channel ACH2. The base station BS does not respond to the individual access channel ACH2.
(T6) The relay terminal RT that monitors T5 and detects no response from the base station BS can transmit an access enable notification to the mobile terminal MT using the first half of the dedicated access channel ACH2 in the second slot. . At this time, it is preferable to use carrier sense. The carrier sense here refers to monitoring the dedicated access channel ACH2, confirming that another station is not communicating, and transmitting an access enable notification.
(T7) In response to T6, the mobile terminal MT transmits an access response to the relay terminal RT using the latter half of the dedicated access channel ACH2 in the second slot. Thereby, the mobile terminal MT can directly communicate with the relay terminal RT via the dedicated access channel ACH2, and thus can indirectly communicate with the base station BS.
(T8) Then, the standby time is reached.
[0030]
With respect to the time slot diagram of FIG. 3, four different sequences will be described.
[0031]
First, at T6, there is a case where the mobile terminal MT has not received the access permission notification.
[0032]
When the relay terminal RT cannot adopt the dedicated access channel ACH2 specified by the mobile terminal MT, the relay terminal RT does not transmit the access permission notification to the mobile terminal MT. Therefore, if the mobile terminal MT has not received the access enable notification from any of the relay terminals RT in the predetermined time, it recognizes that communication is not possible on the dedicated access channel ACH2. At this time, the mobile terminal MT again transmits an access request to which the dedicated access channel number ACH3 is added to the base station 1 (which will not reach) using the first half of the common access channel ACH1 in the first slot. . As a result, this access request is monitored by all relay terminals RT in the communication area of the mobile terminal MT (where radio waves reach), and the mobile terminal MT issues an access enable notification from the relay terminal RT that can adopt the individual access channel number ACH3. Can be received.
[0033]
Second, at T6, a plurality of relay terminals RT may transmit an access enable notification to the mobile terminal MT. In this case, the mobile terminal MT can select the relay terminal RT according to a predetermined condition.
[0034]
C / N (Carrier / Noise) can be used as the predetermined condition. C / N is the ratio of the received signal level to the noise signal level, and the mobile terminal MT selects, from the plurality of relay terminals RT that have received the access response notification, the relay terminal RT having the highest C / N for the access response notification. Can be selected.
[0035]
It is also preferable that the mobile terminal MT that has selected the relay terminal RT notifies the neighboring mobile terminals of the use of the dedicated access channel ACH2 using the second slot. This notification is performed a preset number of times, and if there is no request to stop the channel within the period, use of the dedicated access channel ACH2 is finally determined. This takes into account the fact that the use state of the channel changes depending on the movement and propagation state of the terminal.
[0036]
Third, at T6, if the reception level of the access request received by the relay terminal is smaller than a predetermined C / N, the relay terminal can be configured not to transmit the access enable notification.
[0037]
Fourth, at T5, it is possible not to notify the number of the dedicated access channel at T1 and T4.
[0038]
For the first access request via the common access channel in T1 and T4, it is not necessary to notify the number of the available individual access channel. In this case, when the mobile terminal determines that there is no access response from the base station in T2 and T5, it is possible to transmit an access request including the number of the dedicated access channel again in T1 and T4.
[0039]
The relay terminal RT transmits, to the mobile terminal MT, the number of the individual access channel, which is likely to cause interference or the like when used, among the individual access channel numbers received from the mobile terminal MT as a use stop request. be able to. The mobile terminal MT controls to use a channel other than the dedicated access channel corresponding to the number notified as the use stop request.
[0040]
Further, even if the received signal is smaller than a predetermined C / N, even if the dedicated access channel is being used by another terminal, it is considered that the degree of influence is low even if the same channel is used. It is conceivable to use.
[0041]
Further, even if the C / N exceeds the predetermined C / N, the transmission power is reduced to be smaller than the predetermined C / N and the C / N with the relay terminal to be connected is larger than the predetermined C / N. , The same channel may be used.
[0042]
FIG. 4 is a functional configuration diagram of the relay terminal and the mobile terminal according to the present invention.
[0043]
According to FIG. 4, the relay terminal 3 includes a slot separation unit 31, a common access channel communication unit 32, an individual access channel communication unit 33, a BS response detection unit 34, a relay control unit 35, and an access channel list storage. A part 36.
[0044]
The slot separation unit 31 separates an access channel into a common access channel and an individual access channel. It is preferable that a plurality of individual access channels are prepared.
[0045]
The common access channel communication unit 32 controls communication on the common access channel based on an instruction from the relay control unit 35. In particular, it has a function of transmitting an access request including a number of an available dedicated access channel to a base station via a common access channel, and a function of monitoring a signal of the common access channel.
[0046]
The base station (BS) response detection unit 34 detects that there is no access response from the base station to the access request.
[0047]
The dedicated access channel communication unit 33 controls the communication of the dedicated access channel based on an instruction from the relay control unit 35. In particular, in response to the base station (BS) response detecting unit 34 notifying that there is no access response from the base station, an access enable notification is transmitted to the mobile terminal MT via the dedicated access channel corresponding to the number included in the access request. I do. In addition, in response to the access permission notification, an access permission confirmation is received from the mobile terminal via the dedicated access channel.
[0048]
The relay control unit 35 transmits data received from the mobile terminal MT via the dedicated access channel to the base station BS via the common access channel, and transmits data received from the base station BS via the common access channel to the dedicated access channel. The common access channel communicator 32 and the individual access channel communicator 33 are controlled so as to be transmitted to the mobile terminal MT via.
[0049]
The access channel (ACH) list storage unit 36 stores a list of available individual access channels. For each available individual access channel, information such as whether or not the mobile terminal is currently in use, identification information of the mobile terminal being used, and C / N with the mobile terminal are recorded.
[0050]
According to FIG. 4, the mobile terminal 2 includes a slot separation unit 21, a common access channel communication unit 22, a dedicated access channel communication unit 23, a base station / relay terminal (BS / RT) response detection unit 24, It has a channel (ACH) control unit 25, a relay terminal (RT) determination unit 26, an access channel (ACH) list storage unit 27, and a transmission power control unit 28.
[0051]
The slot separation unit 21 separates an access channel into a common access channel and an individual access channel.
[0052]
The common access channel communication unit 22 controls communication of the common access channel based on an instruction from the access channel (ACH) control unit 25. In particular, the access request including the number of the available dedicated access channel is transmitted to the base station via the common access channel.
[0053]
The base station / relay terminal (BS / RT) response detection unit 24 detects that there is no access response from the base station in response to the access request, and that the access permission notification from the relay terminal has been made.
[0054]
The dedicated access channel communication unit 23 controls communication of the dedicated access channel based on an instruction from the access channel (ACH) control unit 25. In particular, when there is no access response from the base station, the access permission notification received from the relay terminal is notified to the access channel (ACH) control unit 25 via the dedicated access channel corresponding to the number, and the access channel (ACH) ) Based on the control from the control unit 25, the access permission confirmation is transmitted to the relay terminal via the dedicated access channel.
[0055]
When receiving access requests from a plurality of relay terminals, the relay terminal (RT) determination unit 26 selects a relay terminal having the highest received signal level to noise signal level ratio. Alternatively, the relay terminal that first receives the access request is selected.
[0056]
The access channel (ACH) control unit 25 is based on the results of the base station / relay terminal (BS / RT) response detection unit 24 and the relay terminal (RT) determination unit 26, and based on the results of the common access channel communication unit 22 and the dedicated access channel communication. The unit 23 is controlled. Also, the transmission power control means controls the transmission power of the own mobile terminal to such an extent that an access response can be received from at least one relay terminal.
[0057]
The access channel (ACH) list storage unit 27 stores an individual access channel of the relay terminal with which communication is being performed. When the own mobile terminal selects a relay terminal and a dedicated access channel for multi-hop communication, a channel other than the stored relay terminal and channel is used, thereby enabling efficient channel setting.
[0058]
FIG. 5 is a flowchart illustrating a procedure in which a mobile terminal starts a connection according to the present invention.
[0059]
(S51) It is determined whether an access response has been received from the base station via the common access channel.
(S52) If an access response is received from the base station, it directly communicates with the base station via the common access channel.
(S53) If an access response is not received from the base station, an access request to which an available dedicated access channel number is added is transmitted, and a connection on the common access channel is tried again.
(S54) It is determined whether an access response has been received from the base station via the common access channel. If an access response is received from the base station, it communicates directly with the base station via the common access channel.
(S55) If no access response is received from the base station, the dedicated access channel corresponding to the number transmitted by the access request is monitored.
(S56) It is determined whether or not an access notice has been received from the relay terminal. If not received, the process returns to S53.
(S57) Based on the access permission notification received from the relay terminal, it is determined whether communication with the relay terminal can be performed using the dedicated access channel. If communication is not possible, the process returns to S53.
(S58) If communication is possible, the use of the dedicated access channel is notified.
(S59) It is determined whether a request to stop using the dedicated access channel has been received. When the use stop request is received, the process returns to S53.
(S5A) If the use stop request is not received, it is determined whether or not the notification of the dedicated access channel has been performed a preset number of times. If the process has not been performed for the set number of times, the process returns to S58.
(S5B) If the execution has been performed that number of times, the use of the dedicated access channel is started.
[0060]
Since the mobile terminal or the relay terminal is assumed to move, the relay terminal that can communicate or the optimal connection mode changes with time. Therefore, each mobile terminal transmits an access request at regular time intervals using the common access channel ACH1. When the mobile terminal moves into the communication area of the base station BS, the base station BS responds to the access request by the first slot of the common access channel, and the mobile terminal directly connects to the base station BS. Change the connection destination to.
[0061]
The relay terminal also constantly monitors the common access channel ACH1, and when the currently connected mobile terminal MT sends an access request via the common access channel, the relay terminal can access the mobile terminal MT if there is no access response from the base station. A notification is sent to the mobile terminal MT. Thereby, the mobile terminal MT can confirm the changeable relay terminal candidate. Since it is assumed that the access permission notification is received from a plurality of relay terminals, data collision can be prevented by using a carrier sense function or the like. The relay terminal that could not transmit performs transmission in the next slot.
[0062]
The mobile terminal changes the connection mode when there is no response from the currently connected terminal but there is a response from another terminal. This means that the communication distance with the currently connected terminal is long and the communication distance with the terminal that has responded is short.
[0063]
FIG. 6 is a flowchart for changing the connection mode according to the present invention.
[0064]
(S61) It is determined whether an access response has been received from the base station via the common access channel.
(S62) If an access response is received from the base station, it directly communicates with the base station via the common access channel.
(S63) It is determined whether an access permission notification has been received from at least one or more relay terminals.
(S64) If no access permission notification is received, the transmission power of the mobile terminal is increased. Then, maintain the connection with the currently connected relay terminal
(S65) It is determined whether or not the access permission notification has been received from a plurality of relay terminals.
(S66) If the access permission notification is received from a plurality of relay terminals, the relay terminal having the largest C / N is determined and the connection is changed.
(S67) If the access permission notification is received from only one relay terminal, it is determined whether the notification is an access permission notification from a relay terminal other than the currently connected relay terminal.
(S68) If the access permission notification is from a relay terminal other than the currently connected relay terminal, the connection destination is changed.
(S69) If the access permission notification is from the currently connected relay terminal, the connection with the relay terminal is maintained.
[0065]
FIG. 7 is an explanatory diagram showing a change in the communication area when the transmission power is reduced according to the present invention.
[0066]
According to FIG. 7, it is assumed that the mobile terminal MT has transmitted the transmission power of the communication area 42. In this communication area 2, there are two relay terminals 3. At this time, mobile terminal MT only needs to be able to relay at least relay terminal RT-1 and communicate with base station BS. Therefore, it is possible to reduce at least the transmission power of the communication area 43 including the relay terminal RT-1. Such an operation reduces the power consumption of the mobile terminal.
[0067]
On the other hand, it may be more efficient for the mobile terminal MT to maintain the current connection with the relay terminal than to frequently switch the relay terminal. In this case, the current connection state with the relay terminal can be maintained by increasing the transmission power of the own station.
[0068]
According to the above-described various embodiments of the access control method, the relay terminal and the mobile terminal of the wireless multi-hop network in the present invention, various changes, modifications and omissions of the technical idea and scope of the present invention can be made by those skilled in the art. According to this, it can be easily performed. The above description is merely an example and is not intended to be limiting. The invention is limited only as defined by the following claims and equivalents thereof.
[0069]
【The invention's effect】
As described above in detail, according to the wireless multi-hop network access control method, apparatus, and program of the present invention, when a base station and a mobile terminal cannot communicate directly, another terminal relays the information indirectly. Can communicate.
[0070]
In particular, by using a common access channel for communication between the base station and the relay terminal and using an individual access channel for communication between the relay terminal and the mobile terminal, it is possible to prevent channel contention and improve the connection rate. Further, it is easy to change the network configuration as the mobile terminal moves, which leads to a reduction in power consumption of the mobile terminal.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of a conventional wireless network.
FIG. 2 is a system configuration diagram of a wireless multi-hop network according to the present invention.
FIG. 3 is a time slot diagram for elapse of time according to the present invention.
FIG. 4 is a functional configuration diagram of a relay terminal and a mobile terminal according to the present invention.
FIG. 5 is a flowchart illustrating a procedure in which a mobile terminal starts a connection according to the present invention;
FIG. 6 is a flowchart for changing a connection mode according to the present invention.
FIG. 7 is an explanatory diagram showing a change in a communication area when the transmission power is reduced according to the present invention.
[Explanation of symbols]
1 Base station, BS
2 Mobile terminal, MT
21 Slot separation unit
22 Common Access Channel Communication Unit
23 Individual access channel communication unit
24 Base station / relay terminal (BS / RT) response detector
25 Access channel (ACH) control unit
26 Relay terminal (RT) decision unit
27 Access Channel (ACH) List Storage Unit
28 Transmission power control unit
3 Relay terminal, RT
31 Slot separation unit
32 Common Access Channel Communication Unit
33 Individual Access Channel Communication Unit
34 base station (BS) response detector
35 Relay control unit
36 Access Channel (ACH) List Storage Unit
4, 41 Base station communication area
42, 43 Communication area of mobile terminal

Claims (14)

An access control method that enables communication between the mobile terminal and the base station via a relay terminal when the mobile terminal cannot communicate with the base station via a common access channel,
A first step in which the mobile terminal transmits an access request including a number of an available dedicated access channel to the base station via the common access channel;
The relay terminal monitors the access request and transmits an access enable notification to the mobile terminal via the dedicated access channel corresponding to the number when there is no access response from the base station to the access request. A second step to
The mobile terminal transmits the access confirmation to the relay terminal via the dedicated access channel, and the mobile terminal communicates with the relay terminal via the dedicated access channel. An access control method for a wireless multi-hop network, wherein the relay terminal and the base station communicate via the common access channel. The wireless terminal according to claim 1, wherein in the second step, when the access request is received from a plurality of relay terminals, a relay terminal having a highest received signal level to noise signal level ratio is selected. An access control method for a multi-hop network. 2. The access control method according to claim 1, wherein, in the second step, the relay terminal performs carrier sense and transmits an access enable notification to the mobile terminal. 4. The access control of a wireless multi-hop network according to claim 1, wherein in the first step, the access request includes a number of a plurality of available dedicated access channels. 5. Method. The access permission confirmation is monitored by another relay terminal, and when a predetermined condition to deny use of the dedicated access channel for any of the other relay terminals is satisfied, the relay terminal determines the number of the dedicated access channel. A fourth step of transmitting a use suspension request to the mobile terminal, the fourth step including:
The access control method for a wireless multi-hop network according to any one of claims 1 to 4, wherein the process is repeated from the first step except for the number of the dedicated access channel based on the use stop request. 2. The method according to claim 1, wherein in the second step, the mobile terminal controls transmission power of transmission power control means in its own mobile terminal to such an extent that the mobile terminal can receive the access response from at least one of the relay terminals. 6. The access control method for a wireless multi-hop network according to any one of claims 1 to 5. A relay terminal that relays communication between the mobile terminal and the base station when the mobile terminal cannot communicate with the base station via a common access channel,
Common access channel communication means including a number of available dedicated access channels, monitoring an access request transmitted from the mobile terminal to the base station via the common access channel,
Base station response detection means for detecting that there is no access response from the base station to the access request,
Via the dedicated access channel corresponding to the number, transmitting an access enable notification to the mobile terminal, via the dedicated access channel, receiving the access availability confirmation from the mobile terminal, dedicated access channel communication means,
The mobile terminal and the relay terminal communicate with each other via the dedicated access channel, and the relay terminal and the base station have relay control means for controlling to communicate via the common access channel. Terminal of a wireless multi-hop network. The relay control unit is configured to, when the access confirmation is monitored and satisfy a predetermined condition for refusing use of the dedicated access channel, transmit a use stop request including a number of the dedicated access channel to the mobile terminal. The relay terminal for a wireless multi-hop network according to claim 7, wherein 9. The relay terminal according to claim 7, wherein the dedicated access channel communication unit performs a carrier sense and transmits an access enable notification to the mobile terminal. 10. A mobile terminal that enables communication with the base station via a relay terminal when communication with the base station is not possible via a common access channel,
Common access channel communication means for transmitting an access request including a number of available dedicated access channels to the base station via the common access channel,
Base station / relay terminal response detecting means for detecting that there is no access response from the base station in response to the access request, and that access permission notification has been made from the relay terminal
If there is no access response from the base station, via the dedicated access channel corresponding to the number, receive an access enable notification from the relay terminal, via the dedicated access channel, relay the access possibility confirmation relay A mobile terminal of a wireless multi-hop network, comprising: dedicated access channel communication means for transmitting to a terminal; communicating with the relay terminal via the dedicated access channel; and indirectly communicating with the base station. The relay terminal selecting unit according to claim 10, further comprising: the relay terminal selecting unit that selects a relay terminal having a highest received signal level to noise signal level ratio when receiving the access request from a plurality of relay terminals. A mobile terminal in a wireless multi-hop network. The mobile terminal according to claim 10 or 11, wherein the common access channel communication means includes a plurality of available dedicated access channel numbers in the access request. When receiving a use stop request including the number of the dedicated access channel from any of the relay terminals, the common access channel communication unit uses the access request excluding the number of the dedicated access channel based on the use stop request. A mobile terminal in a wireless multi-hop network according to any one of claims 10 to 12, comprising a number of possible dedicated access channels. The transmission power control unit according to any one of claims 10 to 13, further comprising transmission power control means for controlling transmission power of the own mobile terminal to such an extent that the access response can be received from at least one of the relay terminals. A mobile terminal in a wireless multi-hop network.

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