JP3305268B2 - Wireless multicast receiving station group configuration method and wireless station using the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a receiving station group of multicast receiving stations existing in a cell when performing reliable wireless multicast data delivery, and a wireless station using the method.

[0002]

2. Description of the Related Art In conventional multicast communication, a best-effort service is assumed for applications that do not need to guarantee reliability, and compensation for erroneous data is not performed. In addition, when providing a highly reliable multicast (highly reliable multicast), for a multicast data transmitted from a base station, (1) a station that correctly receives the data confirms arrival by an acknowledgment (ACK: Acknowledgment). (2) A station that has detected an error when receiving data receives a negative acknowledgment (NAK: Negative Acknowledgm).
ent) to the multicast transmitting station, and (3) a method combining the above (1) and (2).
A method has been taken to increase the reliability of multicast data by performing retransmission processing as needed.

[0003] In a conventional multicast communication in a wireless environment, the effectiveness of a representative response system for reducing the number of responses by grouping multicast reception stations existing in a cell is known (for example, Inoue, Iizuka, Takanashi, Morikura, "Study of reliable protocol for wireless multicast communication", IEICE,
B-5-211, '97 Spring General Conference, March 1997). As a result, the time required for the delivery confirmation can be reduced, and highly efficient multicast data transfer can be achieved. However, there is no special rule for the grouping method except for the stations that can directly transmit and receive each other.

[0004]

Conventionally, the above (1) to (1)
(3) The wireless multicast communication is performed by such a method. Accordingly, in the reliable multicast communication, since arrival confirmation is performed for each multicast receiving station, there is a problem that the time required for response confirmation increases in proportion to the number of multicast receiving stations. In addition, there has been a problem that the throughput is reduced, or traffic other than the multicast data is compressed.

It has been pointed out that the above problem can be improved by grouping the multicast receiving stations, but no concrete method has been disclosed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wireless multicast communication system for grouping multicast receiving stations, confirming data delivery for each group, suppressing data transmission time, and enabling highly efficient and reliable multicast communication. And a radio station using the method.

[0007]

[0008]

[0009]

[0010]

Means for Solving the Problems To achieve the above object,
Therefore, according to the first aspect of the present invention, a multicast transmitting station creates a frame in which broadcast data is given an identifier of a group of destination receiving stations, and transmits the frame to a multicast receiving station registered as the group of destination receiving stations in one frame transmission. In order to perform wireless multicast communication for transferring broadcast data, the receiving station group includes a receiving station group that is a registered receiving station group registered as the destination receiving station group. In a wireless communication system serving as a representative station for confirming delivery of broadcast data, a multicast receiving station that intends to start the wireless multicast communication monitors a current multicast session, and has at least one If it is recognized that there is a receiving station group of All the response signals to the multicast transmission station are stored together with the reception level of the response signal, and a request signal for joining the representative station having the highest reception level among the stored reception levels to the reception station group is sent to the multicast transmission station. The multicast transmitting station that has transmitted and received the join request signal makes the multicast receiving station a constituent station of a receiving station group indicated by the join request signal, or a receiving station group is located around the multicast receiving station. If the presence of the group cannot be recognized, a group opening request signal of a receiving station group is transmitted to the multicast transmitting station, and the multicast transmitting station receiving the group opening request signal sets the multicast receiving station to a new one. It is characterized in that it is a constituent station of a receiving station group.

The wireless communication system according to the first aspect of the present invention includes a multicast transmitting station that is a wireless station that performs data transfer by wireless multicast and a plurality of wireless stations that receive multicast data transmitted from the multicast transmitting station. It is composed of a multicast receiving station, in which wireless multicast communication using delivery confirmation by the representative station can be performed, for example, as follows. For example, the representative station of each receiving station group shall respond to the arrival confirmation by polling from the multicast transmitting station, and the multicast transmitting station transfers a multicast data frame to a plurality of multicast receiving stations by one frame transmission, Thereafter, polling of the receiving station group causes the representative station of each group to return a response to the multicast data frame. The polled representative station receives an acknowledgment (ACK) when the multicast data frame is correctly received, and If the multicast data frame cannot be received correctly, a negative acknowledgment (NAK) requesting retransmission of the frame that failed to be received is returned to the multicast transmitting station. After the next receiving station group Polls the-loop, when receiving the NAK, to perform the retransmission of the multicast data frames requested by the NAK.

[0012] In such a radio communication system, a radio station newly starting to receive multicast data monitors the current multicast session, and receives all responses from the representative station that have been able to receive the multicast data. If the response is stored together with the reception level and a response from a plurality of representative stations can be received, it joins the group of the representative station having the highest reception level, thereby forming a reception station group. According to the first aspect of the present invention, a station that wants to join a receiving station group joins a group of representative stations that have returned the response of the maximum reception level from among the responses returned by the monitored representative stations. It is possible to participate in the receiving station group existing in the. Therefore, the delivery result (success / failure of receiving the multicast data) can be expected to be the same as that of the representative station of the participating receiving station group with respect to the multicast data delivery from the multicast transmitting station. As a result, the reliability of the response to the returned multicast data is increased, and efficient delivery confirmation is possible.

According to a second aspect of the present invention, a multicast transmission station creates a frame in which broadcast data is given an identifier of a group of destination receiving stations, and the multicast registered as the destination receiving station group in one frame transmission. In order to perform wireless multicast communication for transferring broadcast data to a receiving station, the receiving station group includes a receiving station group including a multicast receiving station registered as the destination receiving station group. In a wireless communication system in which one is a representative station for confirming the delivery of the broadcast data, a multicast receiving station that intends to start the wireless multicast communication monitors an N (N is a natural number) session of the current multicast session. When it is recognized that at least one or more receiving station groups exist around the multicast receiving station. In stores the response signal to the multicast transmission station from a representative station capable of receiving the receive levels of all the response signals, N for each representative station
An average value of the reception level of the response signal of the session is obtained, and a request signal to join the receiving station group of the representative station having the highest reception level among the average values of the representative stations is transmitted to the multicast transmitting station. Upon receiving the request signal, the multicast transmitting station recognizes that the multicast receiving station is a constituent station of a receiving station group indicated by the participation request signal, or that a receiving station group exists around the multicast receiving station. If not, a group opening request signal of a receiving station group is transmitted to the multicast transmitting station, and the multicast transmitting station that has received the group opening request signal configures the multicast receiving station into a new receiving station group. It is characterized by a station.

According to the second aspect of the present invention, a wireless station that wants to newly receive data delivered by multicasting: (1) monitors the current multicast session for N sessions; If the receiving station group does not exist, a group opening request of the receiving station group is sent to the multicast transmitting station. If the receiving station group exists around the own station, that is, the receiving station existing around the own station, When a response from the representative station of the station group can be received, all the responses from the representative station that can be received are stored together with the reception level of the response, and responses from a plurality of representative stations are received. In this case, the average of the reception levels of the N sessions is averaged for each representative station, and a group participation request to the group of the representative station having the highest average reception level is multiplied. Send to strike the transmitting station. And (3)
The multicast transmitting station that has received the group participation request or the group opening request regards the transmission source of the group participation request or the group opening request as a constituent station of the receiving station group indicated by the group participation request or the group opening request. The reception station group is formed by these procedures. According to the third aspect of the present invention, a wireless station newly joining a receiving station group has a maximum average receiving level among responses returned by a plurality of representative stations in N monitored multicast sessions. , It is possible to join the group of the nearest receiving station, and the probability is higher than that of the method described in claim 2. Therefore,
With respect to the delivery of multicast data from the multicast transmitting station, it can be expected with a high probability that the same reception result (success / failure in receiving the multicast data) as the representative station of the participating receiving station group will be obtained with a high probability. , The reliability of the response to the multicast data is increased, and at the same time, efficient delivery confirmation is possible.

According to a third aspect of the present invention, the multicast transmitting station creates a frame in which broadcast data is provided with an identifier of a group of destination receiving stations, and the multicast registered as the destination receiving station group in one frame transmission. In order to perform wireless multicast communication for transferring broadcast data to a receiving station, the receiving station group includes a receiving station group including a multicast receiving station registered as the destination receiving station group. In a wireless communication system in which one is a representative station for confirming the delivery of the broadcast data, a multicast receiving station that intends to start the wireless multicast communication monitors an N (N is a natural number) session of the current multicast session. When it is recognized that at least one or more receiving station groups exist around the multicast receiving station. Storing all response signals from the representative station that can be received to the multicast transmitting station together with the source address of the response signal, and correctly receiving the response signal during N sessions for each representative station. The total number of times the response signal was correctly received, a response request signal was correctly received, a request signal to join the receiving station group of the representative station with the highest number was transmitted to the multicast transmitting station, and the request signal was received. The multicast transmitting station, if the multicast receiving station is a constituent station of the receiving station group indicated by the join request signal, or if it is not recognized that there is a receiving station group around the multicast receiving station, Transmitting a group opening request signal of a receiving station group to the multicast transmitting station, and receiving the group opening request signal. The multicast transmission station is characterized in that to the multicast receiving station a new reception station group configuration station.

According to the third aspect of the present invention, a wireless station newly trying to receive data distributed by multicasting (1) monitors the current multicast session for N sessions, and (2) places the current multicast session near its own station. If the receiving station group does not exist, a group opening request of the receiving station group is sent to the multicast transmitting station. If the receiving station group exists around the own station, that is, the receiving station existing around the own station, When a response from the representative station of the station group can be received, all the responses from the representative station that can be received are stored together with the source address of the response, and N sessions of N sessions are stored for each representative station. Aggregate the number of times a response was successfully received in the meantime, and select from the representative station group of the representative station with the highest number of times the response was successfully received. Send a group request to join a group to the multicast transmission station. (3) The multicast transmitting station that has received the group participation request or the group opening request regards the transmission source of the group participation request or the group opening request as a constituent station of the receiving station group indicated by the group participation request or the group opening request. The reception station group is formed by these procedures.

According to the third aspect of the present invention, a wireless station newly joining a receiving station group represents the number of times of reception of a response that could be received in N monitored multicast sessions. If the responses are accumulated for each station and the responses from a plurality of representative stations can be monitored, the group of the representative station which has received the response correctly the most times will join the group. When a signal transmitted by radio is received, if the transmission speed in the radio section increases, there may be cases where demodulation cannot be performed correctly even if the reception level is high due to the influence of delay spread or the like. On the other hand, a wireless station that is to start receiving multicast data newly needs to monitor the response returned by the representative station of the participating receiving station group. There are cases where it cannot be determined. A wireless station that is to start receiving new multicast data monitors the current multicast session and, when selecting a group of receiving stations to join, introduces a criterion of a response reception result, and By selecting the receiving station group having the largest number of times that the response has been correctly received from the N session monitors, a more reliable receiving station group configuration can be realized.

According to a fourth aspect of the present invention, the multicast transmitting station creates a frame in which broadcast data is provided with an identifier of a group of destination receiving stations, and the multicast registered as the destination receiving station group in one frame transmission. In order to perform wireless multicast communication for transferring broadcast data to a receiving station, the receiving station group includes a receiving station group including a multicast receiving station registered as the destination receiving station group. In a wireless communication system in which one is a representative station for confirming the delivery of the broadcast data, a multicast receiving station that intends to start the wireless multicast communication monitors an N (N is a natural number) session of the current multicast session. When it is recognized that at least one or more receiving station groups exist around the multicast receiving station. Stores all of the response signals from the representative station that can be received to the multicast transmission station together with the reception level and the source address of the response signal, and sets the reception level of the N session response signal for each representative station. The average value is obtained, and the number of times that the response signal has been correctly received during the N sessions for each representative station is totaled. Among the above, transmitting a request signal to join the receiving station group of the representative station having the highest average value of the receiving level to the multicast transmitting station, and receiving the participation request signal, the multicast transmitting station is the multicast receiving station As a constituent station of the receiving station group indicated by the participation request signal, or a receiving station group around the multicast receiving station. If it can not recognize that the present, sending a group establishment request signal receiving station group to the multicast transmitting station,
The multicast transmitting station receiving the group opening request signal sets the multicast receiving station as a constituent station of a new receiving station group.

According to the fourth aspect of the present invention, a radio station newly joining a receiving station group represents the number of times of reception of a response that could be received in N monitored multicast sessions. When the responses from multiple representative stations can be monitored the same number of times by accumulating for each station,
Participate in a group of representative stations having the highest response reception level averaged for each representative station. By this means, a wireless station that is to start receiving new multicast data can monitor the response returned by the representative station from the group of receiving stations with the greatest certainty, and the receiving station group that is located closest to its own station. Participation in is possible. As a result, it is possible to configure the most efficient and most reliable receiving station group at the time of multicast data transmission.

The inventions according to claims 5 to 8 correspond to the multicast receiving stations used in the wireless multicast receiving station group forming method according to claims 1 to 4 , respectively.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, first to fifth embodiments of the present invention will be described with reference to the drawings. The first to fifth embodiments correspond to the inventions described in claims 1 to 5 and the inventions described in claims 6 to 10 in the claims.

<First Embodiment> FIG. 1 is a schematic diagram showing a wireless communication system to which a first embodiment of a wireless multicast receiving station group forming method according to the present invention is applied, and FIG. FIG. 4 is a diagram for explaining a multicast group configuration method according to the embodiment, in which a wireless station that is to start receiving multicast data waits until the wireless station joins a receiving station group existing within a range in which the wireless station can directly transmit and receive; The sequence is explained. FIG. 3 shows a flowchart until the wireless station starts receiving multicast data according to the present invention.

The wireless multicast receiving station group configuration method according to the present embodiment and the other second to fifth embodiments is described in the above-mentioned document “Study of Highly Reliable Protocol for Wireless Multicast Communication”. The present invention is applied to a wireless communication system in which grouping is performed for a plurality of multicast receiving stations existing in such a cell. In this wireless communication system, a plurality of multicast receiving stations in a cell formed by one multicast transmitting station are grouped as one or more groups of receiving stations, and the multicast transmitting station transmits broadcast data to a destination receiving station group. A frame with an identifier is created, and broadcast data is transferred to a plurality of multicast receiving stations registered as a group of destination receiving stations in one frame transmission. Such communication systems can achieve high efficiency and high reliability by grouping. When confirming delivery from the multicast receiving station to the multicast transmitting station, an acknowledgment (AC) is sent to the multicast transmitting station only from a specific station (representative station) in the group.
K), and the other stations in the group monitor the signals of the transmitting station and the representative station so that any station returns a negative acknowledgment (NAK) as needed. More specifically, the transmitting station polls the representative station after the end of the multicast data transmission, and receives the transmission result from the representative station. The other receiving stations in the polled group monitor the signals of the transmitting station and the representative station, and when it is necessary to request retransmission, send the NAK together with the identifier of the receiving station group and information on the corresponding frame. Return to transmitting station. When the transmitting station receives the NAK, it retransmits the requested frame and then performs polling again. By performing this operation for all groups, multicast communication is executed.

In the first embodiment, a multicast receiving station that is to start wireless multicast communication monitors a current multicast session, and (1) recognizes that a receiving station group exists around the multicast receiving station. In this case, a request signal to join the receiving station group is transmitted to the multicast transmitting station, and the multicast transmitting station that has received the joining request signal determines whether the multicast receiving station is a constituent station of the receiving station group indicated by the joining request signal. Or (2) when it is not possible to recognize that a receiving station group exists around the multicast receiving station, transmits a group opening request signal of the receiving station group to the multicast transmitting station and receives the group opening request signal. The multicast transmitting station that has set the multicast receiving station It is an most important feature that the flop configuration station.

In FIGS. 1 and 2, it is assumed that the radio base station (AP (access point)) 100 is a multicast transmitting station, and that the mobile stations 201 to 206 in cells indicated by two-dot chain lines are multicast receiving stations. . In the figure, the mobile stations 201 to 203 include a receiving station group 011 having the mobile station 201 as a representative station, and a mobile station 2
04 and 205 constitute a receiving station group 012 with the mobile station 204 as a representative station, and the mobile station 206 is about to start receiving multicast data newly.

It is assumed that the mobile station 206 is in the state of processing S0 shown in FIG. Before starting the reception of the new multicast data, the mobile station 206 monitors the current multicast session (transmission of one multicast data and exchange of a signal for confirming the arrival thereof). That is, in this case, the mobile station 206 includes the multicast data 301 transmitted from the radio base station 100, the polling 401 exchanged between the radio base station 100 and the mobile station 201 to confirm the arrival, the response 501, and the radio communication. An attempt is made to intercept polling 402 and response 502 exchanged between the base station 100 and the mobile station 204 for confirming arrival. This operation corresponds to the process of S1 in FIG. Response 501,
The determination as to whether or not 502 has been intercepted is made from the received signal level of the response. That is, when the received signal level of the response is equal to or greater than the predetermined threshold L0, it is determined that the response has been intercepted.

In FIG. 2, it is assumed that the mobile station 206 was able to receive the multicast data 301 and the response of the mobile station 204, which is the representative station of the receiving station group 012, in the process of monitoring the multicast session. In this case, the mobile station 206 performs S2 in FIG.
The process proceeds in the Y direction in the processing of the conditional branch 5. The determination of the process 2 in FIG. 3 is to determine that there is a multicast session desired to be received when multicast data can be received from the wireless base station within a predetermined time, and the determination in step S5 is as follows. The reception level is the threshold L
If a response signal from any representative station equal to or greater than 0 can be received, it is determined that there is a receiving station group in the vicinity.
The mobile station 206 performs the process of S6 in FIG. 3 at the end of a series of multicast sessions. That is, the mobile station 206 transmits a request 601 to join the receiving station group to the wireless base station 100. The group join request 601 includes information on the representative station (mobile station 204) that was able to intercept during monitoring of the previous multicast session.

The radio base station 100 sends a group join request 6
01, the mobile station 206 of the transmission source
A response 701 indicating approval is returned. The mobile station 206 responds
3 is received, that is, when the process of S7 in FIG. 3 is performed, the receiving station becomes a member of the receiving station group 012 (the group indicated by the dashed line in FIG. 1), and starts receiving multicast data from the next multicast session. I do.

Therefore, when the multicast data 302 has been transmitted, the mobile station 206 sets the S11 in FIG.
And operates as a member of the receiving station group 012 according to the multicast data transmission / reception procedure. That is, after transmitting the multicast data 302, the radio base station 100 polls the receiving station groups 011 and 012 for arrival confirmation (polling 4).
03, 404), and receives a response from each receiving station group (responses 503, 504). Further, the mobile station 206 transmits the multicast data 302, the polling 404, and the response 5
04, and sends a NAK as necessary.

FIGS. 4 and 5 are second views for explaining the multicast group forming method according to the first embodiment.
This section describes the configuration of the wireless communication system and a sequence until a wireless station that starts to receive multicast data joins a receiving station group that is within a range in which the wireless station can transmit and receive. 4 and 5, the wireless base station 100 is used as a multicast transmitting station and the mobile station 2
Assume 01 to 206 as multicast receiving stations. Also, in the figure, mobile stations 201 to 203 are mobile stations 2
01 as a representative station, and mobile stations 204 and 205 as a representative station group 012 with the mobile station 205 as a representative station. The mobile station 206 newly starts receiving multicast data. Trying to.

A mobile station 206 that is about to start receiving new multicast data monitors the current multicast session before starting to receive it. That is,
Multicast data 301 sent from the wireless base station 100, and polling 401, response 501, polling 402, and response 5 exchanged for arrival confirmation
Attempt to intercept 02.

In FIG. 5, it is assumed that mobile station 206 was able to receive only multicast data 301 followed by polls 401 and 402 during the process of monitoring the multicast session. That is, it is assumed that the response to polling 401 and 402 was not received at a demodulatable level, or was received at a demodulatable level, but was less than threshold value L0. in this case,
The mobile station 206 moves in the Y direction for the processing of S2 in the flowchart of FIG. 3, and N for the processing of S5.
, The response to the polls 401 and 402 could not be intercepted, so that it is determined that there is no receiving station group around the own station.

Therefore, after the end of the multicast session, the mobile station 206 sends a signal to the radio base station 100 as shown in FIG.
Of the group opening request 801 which is the process of S8. When receiving the group opening request 801, the wireless base station 100 sends a group opening response 90 acknowledging the opening of the requested group to the mobile station 206 that is the transmission source.
Send 1

When the mobile station 206 receives the group establishment response 901 in step S9 in FIG. 3, the mobile station 206 newly establishes a receiving station group 013 (step S10 in FIG. 3). Thereby, the mobile station 206 can receive the multicast data, and performs the state of S11 in FIG. 3, that is, receives the multicast data. The radio base station 100 is a mobile station 2
06 is regarded as the representative station of the receiving station group 013, and the subsequent multicast session is started. That is, after transmitting the multicast data 302, the radio base station 100
Polling for arrival confirmation is performed on the reception station groups 011, 012, and 013 (polling 403, 4).
04, 405), and receives a response from each receiving station group (responses 503, 504, 505).

The above operation example describes the case where the mobile station 206 can receive the multicast data 302. However, if the mobile station 206 does not receive the multicast data 302, the processing shown in FIG. The determination result in S2 is N (no reception-desired multi-session), and the mobile station 206 transmits a group establishment request also serving as a multicast data distribution request to the wireless base station 100 (process S3). Upon receiving this multicast data distribution request and group opening request, the mobile station 206 transmits a group opening response to the transmission source mobile station 206, which acknowledges the opening of the requested group.
When the mobile station 206 receives the group establishment response in step S4 in FIG. 3, the mobile station 206 newly establishes a receiving station group (step S10 in FIG. 3). As a result, the mobile station 206
It becomes possible to receive the multicast data, and S1 in FIG.
The state shifts to state 1, that is, multicast data reception is performed.

<Second Embodiment> FIGS. 6 and 7 are diagrams for explaining a second embodiment of the multicast receiving station group forming method according to the present invention, and a system to which the present embodiment is applied. And a sequence until a wireless station starting to receive multicast data joins a receiving station group existing within a range in which the wireless station can directly transmit and receive. In the present embodiment, a multicast receiving station that intends to start wireless multicast communication monitors a current multicast session and has at least one near the multicast receiving station.
When it is recognized that one or more receiving station groups exist, all the response signals from the representative station that can be received to the multicast transmitting station are stored together with the reception level of the response signal, and the stored reception level is stored. A request signal for joining the representative station having the highest reception level in the receiving station group is transmitted to the multicast transmitting station, and the multicast transmitting station that has received the joining request signal sets the multicast receiving station to the receiving station group indicated by the joining request signal. The most important feature of this station is that it is a constituent station.

6 and 7, the radio base station 100 is used as a multicast transmitting station,
09 is assumed as a multicast receiving station. Also, in the figure, mobile stations 201 to 203 include a receiving station group 011 having mobile station 201 as a representative station, and mobile stations 204 to 203.
206 is a receiving station group 0 where the mobile station 205 is a representative station.
12 is a receiving station group 013 in which the mobile stations 207 to 208 have the mobile station 207 as a representative station.
09 is about to start receiving new multicast data. Now, the mobile station 209 is in the state of the processing S0 shown in FIG.

The mobile station 209 that is to start receiving new multicast data monitors the current multicast session before starting to receive. That is,
Multicast data 301 sent from the radio base station 100, and polling 40 exchanged between the radio base station 100 and the mobile station 201 for confirming arrival.
1. Attempts to intercept response 501, poll 402 between wireless base station 100 and mobile station 205, response 502, poll 403 between wireless base station 100 and mobile station 207, response 503. At this time, the mobile station 209 stores all response signals from the representative station that can be received to the multicast transmission station, together with the reception level of the response signal. This operation corresponds to the process of S1 in FIG.

In FIG. 7, the mobile station 209 monitors the multicast session 301, polls 401 to 403, and responds from the mobile station 205 which is the representative station of the receiving station group 012 while monitoring the multicast session.
02 and the response 503 of the mobile station 207, which is the representative station of the receiving station group 013, can be received. At this time, the mobile station 209 sets the response 502 at the received signal level L1 and sets the response 503 at the received signal level L2.
And L1 <L2. At this time, the mobile station 209 proceeds in the Y direction in the processing in the conditional branches of S2 and S5 in FIG.

The mobile station 209 performs the processing of S6 in FIG. 3 at the end of a series of multicast sessions.
That is, the mobile station 209 transmits, to the wireless base station 100, a request 601 to join the receiving station group.
The group join request 601 includes information on the representative station (mobile station 207) that has returned a response that could be intercepted at a high received signal level during monitoring of the previous multicast session.

The radio base station 100 sends a group join request 6
When receiving “01”, a response 701 to the group join request 601 is returned to the mobile station 209 of the transmission source. Mobile station 2
In step 09, when the response 701 is received, that is, when the process in S7 in FIG. 3 is performed, the member becomes a member of the receiving station group 013 and starts receiving multicast data from the next multicast session.

Therefore, when the multicast data 302 has been transmitted, the mobile station 209 performs the processing in S11 in FIG.
And operates as a member of the receiving station group 013 according to the multicast data transmission / reception procedure. That is, after transmitting the multicast data 302, the wireless base station 100 transmits the receiving station groups 011, 012, 01
3 is polled for arrival confirmation (polling 404, 405, 406), and a response is received from each receiving station group (response 504, 505, 506).

<Third Embodiment> FIG. 8 is a view for explaining a third embodiment of the multicast group forming method according to the present invention. This section describes the sequence up to joining a receiving station group existing within a range in which a station can directly transmit and receive. In the present embodiment, a multicast receiving station that intends to start wireless multicast communication monitors the current multicast session by N (N is a natural number), and at least one or more receiving station groups exist around the multicast receiving station. When it is recognized that all the response signals from the representative station that can be received to the multicast transmission station are stored together with the reception levels of the response signals, the average of the reception levels of the response signals of N sessions is stored for each representative station. A request signal for joining the representative station having the highest reception level among the average values of the representative stations to the receiving station group is transmitted to the multicast transmitting station. The main feature is that the station is a constituent station of the receiving station group indicated by the join request signal. It is.

In FIG. 8, as in the case of FIG. 7, it is assumed that the radio base station 100 is a multicast transmitting station, and that the mobile stations 201 to 209 are multicast receiving stations. Also, in the figure, mobile stations 201 to 203 are mobile stations 2
01 as a representative station, a mobile station 204-206 as a representative station with mobile station 205 as a representative station, and mobile stations 207-208 as mobile station 2
A reception station group 013 having a representative station 07 is configured, and the mobile station 209 is about to start receiving multicast data newly. The mobile station 209 is in the state of the processing S0 shown in FIG.

The mobile station 209 that is to start receiving new multicast data monitors the current multicast session N times (N is a natural number) before starting to receive. In the figure, N = 2. That is, the multicast data 3 sent from the wireless base station 100
01 and a response 503 from the subsequent poll 401 and a response 506 from the multicast data 302 and the subsequent poll 404 are attempted. At this time, the mobile station 209 stores all response signals from the representative station that can be received to the multicast transmission station, together with the reception level of the response signal. This operation corresponds to the process of S1 in FIG. In the present embodiment, two consecutive sessions are monitored. However, it is not always necessary to monitor consecutive sessions, and N sessions can be monitored at an arbitrary interval.

In FIG. 8, in the process of monitoring the multicast session, the mobile station 209 sends the responses 502 and 503 following the multicast data 301 at the reception signal levels L1 and L2, respectively, and the response 505 following the multicast data 302. , 506 at reception signal levels L3 and L4, respectively. Here, the response 501 and the response 504 are the reception level threshold L0.
, And was therefore treated as not received. After ending the monitoring of the multicast session, the mobile station 209 averages the received signal level of the intercepted response for each representative station. In the example shown in the figure, the average received signal level of the response returned from the mobile station 205 is (L1 + L
3) / 2, and the average received signal level of the response returned from the mobile station 207 is obtained by (L2 + L4) / 2. FIG.
In the example, it is assumed that (L1 + L3) / 2 <(L2 + L4) / 2. The mobile station 209 proceeds in the Y direction in the processing at the conditional branches of S2 and S5 in FIG.

The mobile station 209 performs the processing of S6 in FIG. 3 at the end of a series of multicast sessions.
That is, the mobile station 209 transmits, to the wireless base station 100, a request 601 to join the receiving station group.
The group join request 601 includes information on the representative station (mobile station 207) that has returned a response that could be intercepted at a high received signal level during monitoring of the previous multicast session.

The radio base station 100 sends a group join request 6
When receiving “01”, a response 701 to the group join request 601 is returned to the mobile station 209 of the transmission source. Mobile station 2
In step 09, when the response 701 is received, that is, when the process in S7 in FIG. 3 is performed, the member becomes a member of the receiving station group 013 and starts receiving multicast data from the next multicast session.

Therefore, when the multicast data 303 has been transmitted, the mobile station 209 performs the processing of S11 in FIG.
And operates as a member of the receiving station group 013 according to the multicast data transmission / reception procedure. That is, after transmitting the multicast data 303, the radio base station 100 sets the receiving station groups 011, 012, 01
3 is polled for confirmation of arrival (polling 407, 4084, 409), and a response is received from each receiving station group (response 507, 508, 509).

<Fourth Embodiment> FIG. 9 is a diagram for explaining a fourth embodiment of the method of forming a multicast receiving station group according to the present invention. The sequence until the wireless station joins a receiving station group existing within a range in which the wireless station can directly transmit and receive is described. In the present embodiment, a multicast receiving station that intends to start wireless multicast communication monitors the current multicast session by N (N is a natural number), and at least one or more receiving station groups exist around the multicast receiving station. When it is recognized that the response signal from the representative station that can be received to the multicast transmission station is stored together with the source address of the response signal, the response signal is correctly stored during N sessions for each representative station. The number of successful receptions was counted, the request signal to join the receiving station group of the representative station with the largest number of times the response signal was correctly received was transmitted to the multicast transmitting station, and the participation request signal was received. The multicast transmitting station associates the multicast receiving station with the constituent stations of the receiving station group indicated by the join request signal. Is the most important feature.

In FIG. 9, it is assumed that radio base station 100 is a multicast transmitting station, and mobile stations 201 to 209 are multicast receiving stations. Also, in the figure,
The mobile stations 201 to 203 include a receiving station group 011 having the mobile station 201 as a representative station, and the mobile stations 204 to 206 include a receiving station group 012 having the mobile station 205 as a representative station.
The mobile stations 207 to 208 constitute a receiving station group 013 having the mobile station 207 as a representative station, and the mobile station 209 is starting to newly receive multicast data. The mobile station 209 is in the state of the processing S0 shown in FIG.

The mobile station 209 that is to start receiving new multicast data monitors the current multicast session N times before starting to receive. In the figure, N = 2. That is, an attempt is made to intercept the multicast data 301 sent from the wireless base station 100 and the response 503 from the subsequent poll 401 and the multicast data 302 and the response 506 from the subsequent poll 404. At this time, the mobile station 209 stores all the response signals from the representative station that can be received to the multicast transmission station together with the source address of the response signal. This operation corresponds to the process of S1 in FIG. In the present embodiment, two consecutive sessions are monitored. However, it is not always necessary to monitor consecutive sessions, and N sessions can be monitored at an arbitrary interval.

In FIG. 9, while monitoring the multicast session, the mobile station 209 fails to receive the response 502 following the multicast data 301 (response 50).
2 has exceeded the threshold value L0 but could not be demodulated correctly), the response 503 was successfully received, and the response 5 following the multicast data 302 was received.
05 and 506 are successfully received. After finishing the monitoring of the multicast session, the mobile station 209 accumulates the total number of successful receptions of the intercepted response for each representative station. In the example of FIG. 7, the number of successful receptions of the response returned by the mobile station 205 is one, and the number of successful receptions of the response returned by the mobile station 207 is two. In the example of FIG. 9, the mobile station 209 is the receiving station group 01 in which the mobile station 207 having a large number of receptions serves as the representative station as a participating receiving station group.
Select 3.

The mobile station 209 performs the processing of S6 in FIG. 3 at the end of a series of multicast sessions.
That is, the mobile station 209 transmits, to the wireless base station 100, a request 601 to join the receiving station group.
The group participation request 601 includes information on the mobile station 207 that is the representative station of the receiving station group selected after the end of the monitoring of the previous multicast session.

The radio base station 100 sends a group join request 6
When receiving “01”, a response 701 to the group join request 601 is returned to the mobile station 209 of the transmission source. Mobile station 2
In step 09, when the response 701 is received, that is, when the process in S7 in FIG. 3 is performed, the member becomes a member of the receiving station group 013 and starts receiving multicast data from the next multicast session.

Therefore, when the multicast data 303 has been transmitted, the mobile station 209 sets the S11 in FIG.
And operates as a member of the receiving station group 013 according to the multicast data transmission / reception procedure as in the case of FIG.

<Fifth Embodiment> FIG. 10 is a diagram for explaining a fifth embodiment of the method for forming a multicast group according to the present invention. This section describes the sequence up to joining a receiving station group existing within a range in which a station can directly transmit and receive. In the present embodiment, a multicast receiving station that intends to start wireless multicast communication monitors the current multicast session by N (N is a natural number), and at least one or more receiving station groups exist around the multicast receiving station. When it is recognized that the response signal from the representative station that can be received to the multicast transmitting station is stored together with the reception level and the source address of the response signal, the response signal of the N session is stored for each representative station. The average value of the reception level is obtained, and the number of times the response signal has been correctly received during the N sessions for each representative station is totaled. A multi-key request signal for a representative station having the highest average reception level in the receiving station group to join the receiving station group. The most important feature of the multicast transmitting station that has transmitted to the multicast transmitting station and received the join request signal is to make the multicast receiving station a constituent station of the receiving station group indicated by the join request signal.

In FIG. 10, it is assumed that radio base station 100 is a multicast transmitting station, and mobile stations 201 to 209 are multicast receiving stations. In the figure, the mobile station 201 includes a receiving station group 011 having the mobile station 201 as a representative station, and mobile stations 204 to 20.
6 is a receiving station group 012 in which the mobile station 205 is a representative station.
Form a receiving station group 013 in which the mobile stations 207 to 208 have the mobile station 207 as a representative station.
Is about to start receiving new multicast data. The mobile station 209 is in the state of the processing S0 shown in FIG.

The mobile station 209 that is to start receiving new multicast data monitors the current multicast session N times before starting to receive. In the figure, N = 2. That is, an attempt is made to intercept the multicast data 301 sent from the wireless base station 100 and the response 503 from the subsequent poll 401 and the multicast data 302 and the response 506 from the subsequent poll 404. At this time, the mobile station 209
All response signals from the representative station that can be received to the multicast transmission station are stored together with the reception level of the response signal and the source address. This operation corresponds to S in FIG.
1 corresponds to the processing of FIG. In this embodiment, two consecutive
Although the number of sessions is monitored, it is not always necessary to monitor consecutive sessions, and N sessions can be monitored at arbitrary intervals.

In FIG. 10, while monitoring the multicast session, the mobile station 209 sends a response 502 following the multicast data 301 at the reception level L1.
Succeeded in receiving the response 503 at the reception level L2,
Also, an example is shown in which the response 505 succeeding the multicast data 302 has been successfully received at the reception level L3 and the response 506 has been successfully received at the reception level L4. Mobile station 20
9 、 After finishing the monitoring of the multicast session,
The total number of successful receptions of the intercepted responses for each representative station is calculated, and the average value of the reception levels of the responses received for each representative station is obtained. In the example shown in the drawing, the number of successful receptions of the response returned by the mobile station 205 is two, and the number of successful receptions of the response returned by the mobile station 207 is also two. At this point, the candidates for the receiving station group in which the mobile station 209 participates have the highest number of successful receptions (in this example, the same number of two times). Next, the mobile station 209 compares the average value of the reception levels of the responses from the representative stations. In the mobile station 209,
The average reception level of the response from the mobile station 205 which is the representative station of the reception station group 012 is obtained by (L1 + L3) / 2. Similarly, in the mobile station 209, the average reception level of the response from the mobile station 207, which is the representative station of the reception station group 013, is obtained by (L2 + L4) / 2. In the example of FIG. 10, it is assumed that (L1 + L3) / 2 <(L2 + L4) / 2. In this case, the mobile station 209 selects, as the participating receiving station group, the receiving station group 013 having the highest average value level and the mobile station 207 serving as the representative station.

The mobile station 209 performs the processing of S6 in FIG. 3 at the end of a series of multicast sessions.
That is, the mobile station 209 transmits, to the wireless base station 100, a request 601 to join the receiving station group.
The group participation request 601 includes information on the mobile station 207 that is the representative station of the receiving station group selected after the end of the monitoring of the previous multicast session.

The radio base station 100 requests the group participation 6
When receiving “01”, a response 701 to the group join request 601 is returned to the mobile station 209 of the transmission source. Mobile station 2
In step 09, when the response 701 is received, that is, when the process in S7 in FIG. 3 is performed, the member becomes a member of the receiving station group 013 and starts receiving multicast data from the next multicast session.

Therefore, when the multicast data 303 has been transmitted, the mobile station 209 sets the S11 in FIG.
And operates as a member of the receiving station group 013 according to the multicast data transmission / reception procedure as in FIGS. 7 and 8.

The above embodiment is an example of a wireless multicast receiving station group forming method according to the present invention and an embodiment of a wireless station using the method. Can be appropriately changed without changing the gist of the present invention. For example, a condition using a maximum value, a minimum value, a fluctuation range, or the like instead of an average value of reception levels in a plurality of receptions as a condition for selecting a representative station of a group to join from a plurality of representative stations. In the case where the determination is made using both the number of successful receptions and the reception level, it is also possible to make a change such as performing the selection based on the reception level and then performing the selection based on the number of successful receptions.

[0065]

According to the first aspect of the present invention, a wireless station that wants to receive multicast data monitors a multicast session, and then (a) performs an existing reception within a range in which the local station can directly transmit and receive. It takes a procedure of joining a station group or (b) forming a receiving station group by itself if there is no existing group, and in any of the above cases, the multicast transmitting station receives the multicast data by itself. It becomes possible to make them recognize. Therefore, as a result, there is an effect that the multicast receiving stations existing in a mutually transmittable / receivable range inside the cell are grouped. As a result, the multicast transmitting station can reduce the number of responses to one multicast data by receiving the response to the transmission data from each group instead of from the individual multicast receiving stations, thereby reducing the transmission delay time. There is an effect that it becomes possible.

Further, since the multicast transmitting station can recognize which wireless station is receiving the multicast data, it is easy to select a representative station of the receiving station group.

Further, since the multicast transmitting station can recognize which wireless station is receiving the multicast data, a wireless station that is not the multicast receiving station deliberately interferes (such as continuously returning NAK). Therefore, it is possible to cope with the above problem, so that it is possible to increase the reliability of the multicast data transfer.

In addition to the above effects, a wireless station newly joining a receiving station group joins a group of representative stations that have returned the response of the maximum reception level from among the responses returned from the monitored representative stations. Therefore, it is possible to participate in the nearest receiving station group. Therefore, the delivery result (success / failure of receiving the multicast data) can be expected to be the same as that of the representative station of the participating receiving station group with respect to the multicast data delivery from the multicast transmitting station. There is an effect that the reliability of the response to the returned multicast data is increased and at the same time efficient delivery confirmation is possible.

According to the second aspect of the present invention, the first aspect is provided.
In addition to the effects of the invention described in (1), the radio station newly trying to join the receiving station group has the maximum average reception level among the responses returned from the plurality of representative stations in the N multicast sessions monitored. Since it participates in the group of the representative station that has returned the response, it becomes possible to participate in the nearest receiving station group, and the probability is higher than in the method described in claim 2. In addition, since the selection of the receiving station group to participate in is determined from the monitoring results of the N multicast sessions, it is less likely to be affected by the instantaneous fluctuation of the received signal level due to fading. Is less likely to occur. Therefore, the delivery result of the multicast data from the multicast transmission station is the same as that of the representative station of the participating receiving station group (success / failure of the reception of the multicast data). There is an effect that the reliability of the response to the multicast data returned by the representative station of the receiving station group that can be expected with a high probability is improved, and that efficient delivery confirmation is possible.

According to the invention described in claim 3 , according to claim 1
In addition to the effects of the invention described in (1), the radio station newly trying to join the receiving station group sets the number of times of reception of the response that could be received in the monitored N multicast sessions for each representative station. If the responses from multiple representative stations can be monitored, the reception level will be high due to the effects of delay spread, etc., because the representative station that has received the responses correctly will participate in the group most frequently. Even when demodulation cannot be performed correctly, there is an effect that erroneous determination can be prevented when selecting a receiving station group to join.

When a wireless station that is to start receiving new multicast data monitors the current multicast session and selects a group of receiving stations to join, it introduces a criterion of a response reception result, By selecting a receiving station group having the largest number of times that a response has been correctly received from the N sessions of the multicast session, there is an effect that a highly reliable receiving station group configuration is possible.

According to the invention described in claim 4 , according to claim 3,
In addition to the effects of the invention described in (1), the radio station newly trying to join the receiving station group sets the number of times of reception of the response that could be received in the monitored N multicast sessions for each representative station. If the responses from multiple representative stations can be monitored the same number of times, a new multicast data reception is started to join the group of the representative station with the highest response reception level averaged for each representative station. The wireless station to be monitored can monitor the response returned by the representative station from the receiving station group most reliably, and has the effect of being able to participate in the receiving station group located closest to its own station. . As a result, the most efficient and most reliable receiving station group can be formed at the time of multicast data transmission.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a communication system to which a receiving station group configuration method according to the present invention is applied (corresponding to FIG. 2).

FIG. 2 is a first diagram for describing a first embodiment of a receiving station group configuration method according to the present invention.

FIG. 3 is a flowchart showing a sequence until a wireless station starts receiving multicast data according to the present invention.

FIG. 4 is a schematic diagram showing a configuration of a communication system to which a receiving station group configuration method according to the present invention is applied (corresponding to FIG. 5).

FIG. 5 is a second diagram for explaining the first embodiment of the receiving station group configuration method according to the present invention.

FIG. 6 is a schematic diagram illustrating a configuration of a communication system to which a receiving station group configuration method according to the present invention is applied (FIGS. 7 to 7);
10).

FIG. 7 is a diagram for explaining a second embodiment of the receiving station group configuration method according to the present invention.

FIG. 8 is a diagram for explaining a third embodiment of the receiving station group configuration method according to the present invention.

FIG. 9 is a diagram for explaining a fourth embodiment of the receiving station group configuration method according to the present invention.

FIG. 10 shows a fifth embodiment of the receiving station group configuration method according to the present invention.
It is a figure for explaining an embodiment.

[Explanation of symbols]

011 to 013 Receiving station group 100 Wireless base station (multicast transmitting station, AP (access point)) 201 to 209 Mobile station (multicast receiving station) 301 to 303 Multicast data 401 to 409 Polling 501 to 509 Response 601 (Multicast receiving station group Request 701 (to the group request 601) Response 801 Group opening request 901 Group opening response L0 Received signal level threshold L1 to L4 Received signal level

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masahiro Morikura 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (56) References JP-A-10-84577 (JP, A) JP-A-7-240965 (JP, A) JP-A-7-321736 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 7/24-7/26 102 H04Q 7 / 00-7/38

Claims (8)

(57) [Claims] 1. A multicast transmission station addressed to broadcast data
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
In the system, the multicast to start the wireless multicast communication is
The receiving station will use the current multicast session
Monitoring at least one or more
If it recognizes that a receiving station group exists,
The multicast transmission from a representative station capable of
All the response signals to the base station are shared with the reception level of the response signal.
And the highest reception among the stored reception levels.
Before the request signal to join the receiving station group of the representative station of the level
Transmitting the participation request signal to the multicast transmitting station.
The multicast transmission station that has received the multicast
To the receiving station indicated by the participation request signal.
A station constituting a loop, or a receiving station group around the multicast receiving station.
If it cannot recognize that a loop exists,
The group establishment request signal of the
To the transmitting station and receive the group opening request signal
The multicast transmitting station that has
Specially, make the receiving station a constituent station of a new receiving station group.
A method for configuring a wireless multicast receiving station group. 2. A multicast transmission station addressed to broadcast data.
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
In the system, the multicast to start the wireless multicast communication is
Cast receiving station, a multicast session of the current row
N (N is a natural number) session monitor, and at least one or more
If it recognizes that a receiving station group exists,
The multicast transmission from a representative station capable of
All the response signals to the base station are shared with the reception level of the response signal.
And the reception level of the response signal of N sessions for each representative station.
Find the average value of the bells, and find the most
Request to join a representative station with a high reception level to a reception station group
Transmitting a signal to the multicast transmitting station,
The multicast transmitting station that has received the request signal
Multicast receiving station is indicated by the join request signal
Make it a constituent station of a receiving station group, or place a receiving station group around the multicast receiving station.
If it cannot recognize that a loop exists,
The group establishment request signal of the
To the transmitting station and receive the group opening request signal
The multicast transmitting station that has
Specially, make the receiving station a constituent station of a new receiving station group.
A method for configuring a wireless multicast receiving station group. 3. A multicast transmission station addressed to broadcast data.
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
In the system, the multicast to start the wireless multicast communication is
The receiving station will use the current multicast session
N (N is a natural number) session monitor, and at least one or more
If it recognizes that a receiving station group exists,
The multicast transmission from a representative station capable of
All the response signals to the base station are the source address of the response signal.
Memorize them together and send a response signal during N sessions for each representative station.
Aggregate the number of successful receptions and generate a response signal
Reception of the representative station with the highest number of successful receptions
A request signal for participation in a broadcasting station group is transmitted by the multicast.
Transmitting to the communication station and receiving the participation request signal.
The cast transmitting station references the multicast receiving station.
As a constituent station of the receiving station group indicated by the addition request signal.
That, alternatively, the receiving station grayed around the multicast receiving station
If it cannot recognize that a loop exists,
The group establishment request signal of the
To the transmitting station and receive the group opening request signal
The multicast transmitting station that has
Specially, make the receiving station a constituent station of a new receiving station group.
A method for configuring a wireless multicast receiving station group. 4. A multicast transmission station addressed to broadcast data
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
In the system, the multicast to start the wireless multicast communication is
The receiving station will use the current multicast session
N (N is a natural number) session monitor, and at least one or more
If it recognizes that a receiving station group exists,
The multicast transmission from a representative station capable of
All the response signals to the base station are received level of the response signal and
Stored with source address, N sessions for each representative station
The average value of the response level of the response signal of
Correctly receive response signals during N sessions for each station
The number of times that the
In the receiving station group of the representative station with the highest number of times
The receiving station of the representative station having the highest average value of the receiving level.
A request signal for joining a group is sent to the multicast transmitting station.
To the multicast that has received the participation request signal.
The transmitting station transmits the multicast receiving station to the
Request to be a constituent station of the receiving station group indicated by the request signal, or a receiving station group around the multicast receiving station.
If it cannot recognize that a loop exists,
The group establishment request signal of the
To the transmitting station and receive the group opening request signal
And said multicast transmitting station, the multicast
Specially, make the receiving station a constituent station of a new receiving station group.
A method for configuring a wireless multicast receiving station group. 5. A multicast transmission station addressed to broadcast data.
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
A multicast receiving station in the system, when trying to start the wireless multicast communication,
Monitors the current multicast session, and if there is at least one receiver group near the own station
Can be received if it recognizes that
A response signal from the representative station to the multicast transmitting station;
All of which are stored together with the reception level of the response signal;
Of the representative station with the highest reception level among the received reception levels
In order to become a constituent station of the receiving station group, the receiving station group
A request signal to join to the multicast transmitting station
And, or, that there is a receiving station groups around the mobile station
Is not recognized, a new receiving station group
To be a constituent station, you need to set up a receiving station group.
Transmitting a request signal to the multicast transmitting station.
The radio station to call. 6. A multicast transmission station addressed to broadcast data.
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
A multicast receiving station in the system, when trying to start the wireless multicast communication,
Set the current multicast session to N (N is a natural number)
Monitor, and if there is at least one receiving station group around the own station.
Can be received if it recognizes that
A response signal from the representative station to the multicast transmitting station;
All are stored together with the reception level of the response signal, and each representative station is stored.
The average of the reception levels of the response signals of N sessions
Therefore, the highest reception level among the average values of the representative stations is
To become a constituent station of the receiving station group of the representative station,
Multicast transmission of a request signal to join a station group
Transmitting to the station or receiving station group around the station
Is not recognized, a new receiving station group
To be a constituent station, you need to set up a receiving station group.
Transmitting a request signal to the multicast transmitting station.
The radio station to call. 7. A multicast transmission station addressed to broadcast data.
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
A multicast receiving station in the system, when trying to start the wireless multicast communication,
Set the current multicast session to N (N is a natural number)
Monitor, and if there is at least one receiving station group around the own station.
Can be received if it recognizes that
A response signal from the representative station to the multicast transmitting station;
All are stored together with the source address of the response signal, and the representative station
Receiving the response signal correctly during each N sessions
Count the number of times a response was made and correctly receive the response signal
Of the receiving station group of the representative station that performed the most times
In order to become a station, a request signal to join the receiving station group is sent.
Transmitting to the multicast transmitting station, or that a receiving station group exists around the own station
Is not recognized, a new receiving station group
In order to become a configuration stations, groups established cornerstone of the receiving station group
Transmitting a request signal to the multicast transmitting station.
The radio station to call. 8. A multicast transmission station addressed to broadcast data.
Create a frame with the identifier of the destination receiving station group, and
The frame registered as the destination receiving station group in the frame transmission of
A wireless multi that transfers broadcast data to a multicast receiver.
To perform cast communication, register as the destination receiving station group.
The receiving station group that has the recorded multicast receiving station as a constituent station
A loop in which one of the constituent stations of the receiving station group is
Wireless communication system as a representative station for confirming delivery of broadcast data
A multicast receiving station in the system, when trying to start the wireless multicast communication,
Set the current multicast session to N (N is a natural number)
Monitor at least one receiving station group exists around
Can be received if it recognizes that
A response signal from the representative station to the multicast transmitting station;
All of them together with the reception level and the source address of the response signal
And the reception level of the response signal of N sessions for each representative station.
Calculate the average value of the bell and N sessions for each representative station
The number of times a response signal was received correctly during
The number of times that a response signal was received correctly.
Among the receiving station groups of representative stations
Of the receiving station group of the representative station with the highest average value of
In order to become, the participation request signal to the receiving station group
Transmit to the multicast transmitting station, or a receiving station group exists around the local station
Is not recognized, a new receiving station group
To be a constituent station, you need to set up a receiving station group.
Transmitting a request signal to the multicast transmitting station.
The radio station to call.