WO2016171280A1 - Wireless terminal, wireless communication method, and integrated circuit for wireless communication - Google Patents

Abstract

[Problem] To efficiently manage wireless terminals for OFDMA and resource blocks used by the wireless terminals. [Solution] A wireless terminal according to an embodiment of the present invention is provided with an antenna, a wireless communication unit, and a control unit. The control unit effects a control for transmitting, via the wireless communication unit, a first frame including, of first information comprising a first group to which a plurality of wireless terminals belong, a second group to which a plurality of wireless terminals belong, identification information of the wireless terminals that belong to the first group, and identification information of the wireless terminals that belong to the second group, at least second information about a first wireless terminal, and for transmitting, via the wireless communication unit and after the transmission of the first frame, a second frame including third information comprising information designating the first group for OFDMA communication, and information for identifying a resource block to be allocated to the plurality of wireless terminals that belong to the first group.

Description

Wireless terminal, wireless communication method, and integrated circuit for wireless communication

Embodiments described herein relate generally to a wireless terminal, a wireless communication method, and an integrated circuit for wireless communication.

多重 Downlink multi-user MIMO (DL-MU-MIMO), which is an extension of MIMO (Multi-Input Multi-Output), is a multiplexing technology that improves frequency utilization efficiency. In downlink multi-user MIMO, the base station (AP: Access フ ォ ー Point) uses beam forming to enable data transmission using spatially orthogonal beams to each wireless terminal (STA: STAtion). Different data can be transmitted simultaneously to other wireless terminals. Here, the base station manages a plurality of wireless terminals that are the transmission destinations of the downlink multiuser MIMO using the Group ID.

As another multiplexing technique, OFDMA (Orthogonal Frequency Division Multiple Multiple Access), which assigns resource blocks having a plurality of subcarriers as a unit to a plurality of wireless terminals and communicates simultaneously, has attracted attention. In OFDMA, a base station can simultaneously communicate with a plurality of wireless terminals using a plurality of resource blocks.

However, in the conventional technique, there is no method for efficiently managing a plurality of wireless terminals to be communicated and resource blocks used by each wireless terminal in OFDMA.

JP 2013-201472

An embodiment of the present invention aims to efficiently manage a wireless terminal that is an OFDMA communication target and resource blocks used by each wireless terminal.

A wireless terminal as an embodiment of the present invention includes an antenna, a wireless communication unit, and a control unit. The control unit includes a first group to which a plurality of radio terminals belong, a second group to which a plurality of radio terminals belong, identification information of each radio terminal belonging to the first group, and each radio terminal belonging to the second group 1st information including at least second information related to the first wireless terminal is transmitted via the wireless communication unit, and after transmission of the first frame, OFDMA communication is performed. A second frame including third information including information specifying the target first group and information for specifying resource blocks to be allocated to the plurality of wireless terminals belonging to the first group; Control to transmit via the unit.

1 is a configuration diagram of a wireless communication system according to a first embodiment. Explanatory drawing of a resource block. The figure which shows an example of the group information which the base station produced. The figure which shows assignment of User Position to a resource block. The figure which shows an example of a Group <> ID <> Management frame. The figure which shows an example of the frame in downlink OFDMA communication. The figure which shows an example of the frame sequence in uplink OFDMA communication. The figure which shows an example of the PHY header in the modification 1. FIG. 10 is a diagram illustrating an example of a PHY header in a second modification. The figure which shows an example of the group information which the base station produced. The figure which shows the block configuration of the radio | wireless communication apparatus mounted in a base station. The figure which shows the block configuration of the radio | wireless communication apparatus mounted in a radio | wireless terminal. The flowchart of the downlink OFDMA communication of a base station. The flowchart of the downlink OFDMA communication of a radio | wireless terminal. The flowchart of the uplink OFDMA communication of a base station. The flowchart of the uplink OFDMA communication of a radio | wireless terminal. FIG. 9 is a functional block diagram of a base station or terminal according to a second embodiment. 10 shows an example of the overall configuration of a terminal or a base station according to a third embodiment. FIG. 10 is a diagram illustrating an example of a hardware configuration of a wireless communication device mounted on a base station or terminal according to a third embodiment. FIG. 9 is a perspective view of a wireless terminal according to a fourth embodiment. The figure which shows the memory card based on 4th Embodiment. FIG. 20 shows an example of a frame exchange during a contention period according to the thirteenth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. IEEE Std 802.11 ^TM- 2012 and IEEE Std 802.11ac ^TM- 2013, known as wireless LAN standards, are all incorporated herein by reference.

(First embodiment)
FIG. 1 is a configuration diagram of a wireless communication system including a base station and a wireless terminal according to the first embodiment. This wireless communication system is assumed to communicate in accordance with the IEEE 802.11 standard. However, the IEEE 802.11 standard is an example, and the embodiment described in this specification may be applied to other wireless communication standards and wireless communication systems. A base station is also a form of a wireless terminal, and is mainly different from a wireless terminal of a non-base station in that it has a relay function.

In FIG. 1, wireless terminals (STA: STAtion) 201 to 210 are connected to a base station (AP: Access Point) 101 to form one wireless communication system or wireless communication group. Here, the connection means a state where a wireless link is established. Each wireless terminal completes the exchange of parameters necessary for communication through an association process with the base station, whereby a wireless link is established. In this state, the base station and the wireless terminal know each other's capabilities (whether or not to support OFDMA communication). In FIG. 1, 10 wireless terminals are shown, but 10 or more wireless terminals may exist, or 9 or less wireless terminals may exist. Further, both the base station and the wireless terminal may be provided with one antenna, or may be provided with two or more antennas to support MIMO communication. Note that the frame according to the present embodiment may be called not only a frame in the IEEE802.11 standard but also a packet.

In FIG. 1, the base station 101 and each wireless terminal are equipped with wireless communication devices for communicating with each other. The wireless communication device mounted on each wireless terminal communicates with the wireless communication device mounted on the base station 101. The wireless communication device mounted on the base station 101 communicates with the wireless communication device mounted on each wireless terminal. The configuration of the wireless communication device will be described later.

The base station 101 of this embodiment allocates one or more resource blocks to each wireless terminal and communicates with these wireless terminals simultaneously. Such a communication method is called resource block-based OFDMA (OrthogonalgonFrequency Division Multiple Access). Here, the resource block is a frequency resource configured with one or a plurality of subcarriers as one unit. When configured with a plurality of subcarriers, the resource block is continuous even if the arrangement of each subcarrier is continuous. You don't have to. In this embodiment, it is called a resource block, but another expression can be used. For example, it may be called a resource unit, subchannel, or frequency block instead of a resource block. It is also possible to assign a plurality of subcarriers arranged discontinuously as a resource block to one wireless terminal.

FIG. 2 is a diagram illustrating an example of a resource block. In this example, a plurality of channels are arranged in the frequency domain, and a plurality of subcarriers are arranged in each channel so as to be orthogonal to each other. The figure shows two resource blocks, RB (Resource Block) 1 and RB2. The width of the resource block can be set to 5 MHz, for example. The width of the resource block to be allocated may be changed for each wireless terminal. Here, two subcarriers are arranged as guard subcarriers between RB1 and RB2. The number of guard subcarriers is not limited to 2 and can be any number of 1 or more. Moreover, it is also possible to assign without arranging guard subcarriers between resource blocks (zero guard subcarriers).

In resource block-based OFDMA, one or a plurality of resource blocks are assigned to each wireless terminal, and the base station can communicate simultaneously with the plurality of wireless terminals to which the resource block is assigned. In this embodiment, the base station 101 creates group information for managing a plurality of wireless terminals to be communicated and resource blocks used by each wireless terminal. Then, the base station 101 notifies the created group information to each wireless terminal. Each wireless terminal uses the group information notified from the base station 101 to determine whether its own device is a target of OFDMA communication, and identifies a resource block to be used when it is a target of communication.

(Create group information)
FIG. 3 is a diagram showing an example of group information created by the base station 101. As shown in FIG. “GID” represents Group ID, and “UP” represents User Position assigned to each group member. In this example, GID is 6 bits (0 to 63), and “GID0” indicates that the Group ID is 0. UP is 2 bits (0 to 3), and “UPO” indicates that User Position is 0. GID 0 and 63 are assumed to be used as numbers indicating special purposes (eg, non-OFDMA communication, state before group definition, etc.), and are not used (Reserved) as OFDMA groups. .

In GID1 in FIG. 3, STA201 is assigned to UP0, STA202 to UP1, STA203 to UP2, and STA204 to UP3. Similarly, in GID2, STA205, STA206, STA201, and STA202 are assigned to UP0 to UP3, respectively. Further, as indicated by GID4, the base station 101 can also assign a plurality of wireless terminals to the same User-Position.

The base station 101 notifies the created group information to each wireless terminal before starting OFDMA communication (details of the notification method will be described later). Then, when performing OFDMA communication, information specifying a group to be communicated and information related to User Position assigned to each resource block are transmitted to each wireless terminal. For example, when base station 101 designates GID1 when performing OFDMA communication, STAs 201 to 204 which are members of this group are targets of OFDAM communication. Furthermore, the base station 101 can specify the resource block used by each wireless terminal by notifying information indicating the correspondence between the resource block and the User-Position as shown in the table of FIG. This example assumes a case where the channel width is 20 MHz and the width of each resource block is 5 MHz, and a radio terminal 204 corresponding to UP3 of GID1 is assigned to RB1.

In addition, when the correspondence relationship as shown in the table of FIG. 4B is notified, not only RB1 but also RB4 is assigned to the wireless terminal 204 corresponding to UP3 of GID1. That is, a plurality of resource blocks can be assigned to one wireless terminal. Details of designation of the User-Position assigned to the communication target group and each resource block by the base station 101 will be described later.

The base station 101 creates group information as shown in FIG. 3 for a wireless terminal (a wireless terminal included in a BSS (Basic Service Set)) that has established a communication link with its own device. Here, the base station 101 obtains information on capabilities of each wireless terminal (presence / absence of compliance with OFDMA, compliance standard information, etc.), position information of each wireless terminal, and arrival angle estimation result of each radio terminal. The group information can be created using propagation path information between the base station 101 and each wireless terminal. For example, group information can be created so that wireless terminals with a high correlation of propagation paths or wireless terminals with close arrival angles of radio waves belong to the same group. In addition, if the BSS includes wireless terminals that do not support OFDMA communication (for example, legacy terminals that communicate according to standards such as IEEE802.11b / g / n / ac), group information is created excluding this wireless terminal. You can also

In this embodiment, Group ID and User Position are used as group information, but the configuration of group information is not limited to this. An arbitrary format can be used as group information as long as it includes information that can manage a plurality of wireless terminals to be subjected to OFDMA communication and resource blocks used by each wireless terminal. User Position is information (identification information) for identifying each wireless terminal in the group, but the order of each wireless terminal in the group may be used as this identification information instead of User Position. Moreover, you may make it provide a symbol instead of a number as an identifier. The same identifier may be assigned to a plurality of wireless terminals in the same group.

(Notification of group information)
The base station 101 notifies the created group information to each wireless terminal using a predetermined frame. In the present embodiment, the base station 101 notifies each wireless terminal of group information using a Group ID Management frame defined in IEEE802.11ac.

FIG. 5 is a diagram showing an example of a Group ID Management frame in the present embodiment. The Group ID Management frame is a management frame and includes an FC (Frame Control) field, a Duration / ID field, an RA (Receiver Address) field, a TA (Transmitter Address) field, a Frame Body field, and an FCS (Frame Check Sequence) field. The Frame Body field includes a Membership Status Array field and a User Position Array field.

In the FC field, information indicating the frame type is stored.

In the Duration / ID field, the time set as virtual carrier sense is stored.

In the RA field, the MAC address of the frame transmission destination is stored. When a Group ID management frame is transmitted to the wireless terminal 201, the MAC address of the wireless terminal 201 is stored.

The MAC field of the frame transmission source is stored in the TA field. In this embodiment, the MAC address of the base station 101 is stored.

In the Frame Body field, the data body transmitted from the base station 101 to each wireless terminal is stored. In the present embodiment, group information related to the wireless terminal specified in the RA field among the group information created by the base station 101 is stored in the Membership Status Array field and User Position Array field.

The FCS information of the frame is stored in the FCS field. The FCS information is used for frame error detection on the wireless terminal side that has received the frame.

Here, the Membership Status Array field and User Position Array field included in the Frame Body field will be described.

The Membership Status Array field is a field for notifying which group the wireless terminal specified in the RA field belongs as a member. In this example, affiliation information about Group ID 0 to 63 is notified. When “Membership Status In Group ID 1” in the Membership Status Array field is “0”, this indicates that this wireless terminal is not a member of Group ID 1; when it is “1”, it is a member of Group ID 1. It represents that. For example, in the case of the group information in FIG. 3, since the wireless terminal 201 is a member of GID1, 2, and 4 but not a member of GID3, the “Membership Status In In Group ID” of the Group ID Management frame transmitted to the wireless terminal 201 is used. The fields from 1 to ID 4 are “1, 1, 0, 1”, respectively.

The User Position Array field is a field for notifying the User Position of the wireless terminal in each group. In this example, User Position in the group of Group ID 0 to 63 is notified. When “User Position In Group ID 1” in the User Position Array field is “1”, the user position of the wireless terminal in Group ID 1 is “1”. For example, in the case of the group information shown in FIG. 3, the wireless terminal 201 is UP0 for GID1, UP2 for GID2, is not a member for GID3, and is UP0 for GID4. The fields of “Group ID 1 to ID 4” are “0, 2, Reserved, 0”, respectively.

As described above, since Group IDs 0 and 63 are used for special purposes, Membership Status In Group ID 0, ID 63, Membership Status In Group ID 0, and ID 63 become Reserved.

In this way, the base station 101 creates a Group ID Management frame including group information related to the wireless terminal for each wireless terminal, and transmits the frame before starting OFDMA communication. In the case of FIG. 1, since the BSS of the base station 101 includes 10 wireless terminals 201 to 210, the base station 101 creates 10 Group ID Management frames and transmits them to each wireless terminal. .

In this embodiment, the group information is notified using the Group ID Management frame, but the group information may be notified using a Beacon frame, an Association Response frame, or the like. Alternatively, a new frame may be separately defined and the group information may be notified using this frame, or may be notified using the Reserved bit of the existing frame. Further, the Group ID Management frame may not be transmitted to wireless terminals that do not appear in the group information (wireless terminals that do not belong to any group).

In the present embodiment, group information related to the wireless terminal specified in the RA field is notified from the group information, but group information related to other wireless terminals may be notified together. At that time, the base station 101 may store a plurality of Membership Status Array fields and User Position Array fields in which values are set for each wireless terminal in the Frame Body field. Further, the base station 101 may aggregate Group ID Management frames for each wireless terminal.

The base station 101 may notify the group information not by unicast but by multicast or broadcast.

(Downlink OFDMA communication)
A case will be described in which base station 101 transmits a frame to a plurality of wireless terminals by downlink OFDMA communication. Here, it is assumed that each wireless terminal has received a Group ID Management frame for its own device from the base station 101 and has grasped at least group information regarding the own device among the group information shown in FIG.

FIG. 6 shows an example of a frame that the base station 101 transmits to a plurality of wireless terminals by OFDMA. In this example, the base station 101 transmits a frame using four resource locks RB1 to RB4. Assume that each resource block is arranged in the order of RB1 to RB4 from the lowest frequency to the highest frequency. In the PHY header, information specifying a group to be subjected to OFDMA communication and information related to User Position to be allocated to each resource block are stored. In the data field, the data body transmitted by the base station 101 is stored. Here, it is assumed that the PHY header in this document also includes a preamble field. Details of the PHY header will be described below.

The GID field of the PHY header stores the ID of the group targeted for downlink OFDMA communication. For example, when the base station 101 has data for STA201, STA202, and STA204 in the buffer, set “1” of GID1 or “4” of GID4 to which these wireless terminals belong as members. Thus, STA201, STA202, and STA204 can be targeted for OFDMA communication. In this example, GID4 includes more members (STA203, STA205 to STA210) that are not targets of OFDMA communication than GID1 (only STA203 in the case of GID1). When a plurality of groups exist as candidates, the base station 101 may select a Group ID that has few members that are not OFDMA communication targets. As a result, it is possible to avoid a wireless terminal that is not subject to OFDMA communication from executing useless reception processing. When the GID is 0 to 63, the GID field can be composed of 6 bits.

In the field following the GID field, information related to User Position assigned to each resource block is stored. The UP of RB1 field stores user position information assigned to RB1. When RB1 is desired to be assigned to STA 204 that is a member of GID1, base station 101 may set “1” in the GID field and “3” in the UP of RB1 field. Similarly, when RB2 and RB3 are assigned to STA201 and RB4 is assigned to STA202, “0” may be set in the fields of UP of RB2 and UP of RB3, and “1” may be set in the UP of RB4 field. Here, GID 1 UP 2 (corresponding to STA 203) is not assigned to any resource block, and therefore no data is transmitted to the wireless terminal 203. When UP is 0 to 3, UP of RB1 to 4 can be composed of 2 bits each.

MAC frames 1 to 4 in the data field are data for the wireless terminal specified by the PHY header. In the above example, MAC frame 1 is for STA204, MAC frames 2 and 3 are for STA201, and MAC frame 4 is for STA202. Become data. The header of each MAC frame has an RA field, which stores the MAC address of the destination wireless terminal.

The base station 101 can also allocate a plurality of resource blocks to one wireless terminal. For example, when RB1 and RB2 are assigned to STA201 and RB3 and RB4 are assigned to STA202 and data is transmitted, base station 101 sets “1” in the GID field and “0” in the UP of RB1 to 2 field. Set “1” in the fields of of RB3 ~ 4.

Next, the operation of the wireless terminal in downlink OFDMA communication will be described. When each wireless terminal receives the PHY header of the frame transmitted by the wireless terminal 101, each wireless terminal analyzes the GID field and grasps whether or not its own device is a target of OFDMA communication. For example, the wireless terminal 201 is a group to which the own device belongs as a member when any one of “1, 2, 4” is set in the GID field using the group information received in advance from the base station 101. That is, it is possible to grasp that the own apparatus is a target of OFDMA communication. Then, the wireless terminal 201 can analyze the next field of UP of RB1 to 4 and receive the MAC frame with the resource block allocated to the own device. On the other hand, when “3” is specified in the GID field, the wireless terminal 201 can recognize that the wireless device 201 is not a group to which the wireless device 201 belongs as a member, that is, the wireless device 201 is not subject to OFDMA communication. .

When multiple wireless terminals are assigned to the same User Position as in GID4, standby processing is performed with resource blocks to which multiple wireless terminals are assigned, and the same MAC frame is received. For example, if “4” is set in the GID field of the frame transmitted from the base station 101 and “1” is set in the UP of RB1 field, three wireless terminals (STA202, STA206, STA210) have the same MAC in RB1. Frame reception processing is performed. In this case, each wireless terminal can determine whether or not this MAC frame is addressed to itself by checking the RA field of the received MAC frame. For example, when the MAC address of the STA 210 is stored in the RA field, the wireless terminal 210 continues the reception process on the assumption that the data is for its own device. On the other hand, the wireless terminals 202 and 206 can discard the received MAC frame on the assumption that the data is not intended for the device itself.

In the above description, the base station 101 stores the information specifying the group to be subjected to OFDMA communication in the PHY header of the data to be transmitted in the downlink by OFDMA communication and the information regarding the User Position allocated to each resource block. Such information may be notified in advance using another frame.

(Uplink OFDMA communication)
A case where a plurality of wireless terminals transmit frames to the base station 101 by uplink OFDMA communication will be described. Here, it is assumed that each wireless terminal has received a Group ID Management frame for its own device from the base station 101 and has grasped at least group information regarding the own device among the group information shown in FIG.

FIG. 7 is a diagram showing a frame sequence in uplink OFDMA communication. Here, the Poll frame is a frame that the base station 101 transmits to a plurality of wireless terminals, and each wireless terminal starts uplink OFDMA communication triggered by reception of the Poll frame.

Frames 1 to 4 represent frames that have been uplink-transmitted to the base station 101 by a plurality of wireless terminals specified by the Poll frame. In the present embodiment, these frames are transmitted after the time T1 has elapsed since the reception of the Poll frame. T1 may be SIFS (Short | InterFrame | Space) which is the time interval between frames prescribed | regulated by IEEE802.11 standard, and may be arbitrary time length other than that. The arbitrary time length may be counted not from after reception of the Poll frame but from another time point.

As in the case of the downlink described above, the Poll frame stores a GID field that stores the ID of a group to be subjected to uplink OFDMA communication, and UP of RB1 to store information on the User Position allocated to each resource block. It has 4 fields.

Each wireless terminal that has received the Poll frame analyzes whether it is the target of OFDMA communication by analyzing the GID field and UP of RB1 to 4 fields as in the case of the downlink described above. To grasp. A radio terminal that is a target of OFDMA communication identifies a resource block to be used for uplink data transmission, and transmits a frame using the identified resource block after a lapse of T1 time from the reception of the Poll frame.

For example, when “2” is set in the GID field of the Poll frame and “0, 1, 2, 3” is set in the fields of UP of RB1 to 4, respectively, the wireless terminal 205 is determined from the group information in FIG. Transmits the frame 1, the wireless terminal 206 transmits the frame 2, the wireless terminal 201 transmits the frame 3, and the wireless terminal 202 transmits the frame 4 to the base station 101 in uplink.

In FIG. 7, frames 1 to 4 are transmitted in different resource blocks, but a common signal is stored in a plurality of wireless terminals in the PHY header of each frame, and each wireless terminal May be transmitted using the entire RB1 to RB4. A common signal may be transmitted through a channel covering RB1 to RB4. For example, when RB1 to RB4 are 5 MHz wide, a common signal may be transmitted through a 20 MHz wide channel in which these are bundled, and the subsequent data portion may be transmitted in a resource block assigned to each wireless terminal. .

In FIG. 7, the base station 101 transmits the Poll frame in the same frequency band as the resource block allocated to the wireless terminal. However, the base station 101 transmits the Poll frame using a different frequency band (different channel). May be.

In this embodiment, the base station 101 uses the Poll frame to notify the GID field and the UP of RB1 to 4 fields, but may notify these information using other management frames or control frames. Good. Also, notification may be made using a newly defined new frame, or may be made using the Reserved bit of an existing frame.

As described above, according to the present embodiment, the base station creates a group to which a plurality of wireless terminals belong and identification information of each wireless terminal in the group, and notifies each wireless terminal. Then, when performing OFDMA communication, information specifying a group to be subjected to OFDMA communication and information related to identification information of a wireless terminal assigned to each resource block are notified to each wireless terminal. As a result, it is possible to efficiently manage the radio terminal to be communicated by OFDMA and the resource blocks used by each radio terminal.

(Modification 1)
In the examples so far, four resource blocks RB1 to RB4 have been described, but the number of resource blocks used for OFDMA communication is not limited to this. For example, 32 resource blocks of 5 MHz width may be arranged for a channel width of 160 MHz. Here, the number of User Positions may be equal to the number of resource blocks, or may be a different value.

When aligning the number of User Positions with the number of resource blocks, User Position can be represented by 5 bits from 0 to 31. FIG. 8 (a) shows the GID field and UP of RB [n] field (n is an integer from 1 to 32) set in the PHY header when the base station 101 performs OFDMA communication. Since 0 ~ 31 User の Position is set in the UP of RB [n] field, the number of bits in each field is 5.

When User Position is expressed by 2 bits from 0 to 4 (when the number of User Position is different from the number of resource blocks), as shown in Fig. 8 (b), each field of UP of RB [n] set in the PHY header The number of bits becomes 2. Thus, the total number of bits in the field of UP RB n used by the base station 101 during OFDMA communication varies depending on the number of resource blocks and the number of User Positions used.

Also, the base station 101 can extend the Group ID used in the group information to 0 to 255 (8 bits), for example, instead of 0 to 63 (6 bits). In this case, the number of bits of the GID field set in the PHY header when the base station 101 performs OFDMA communication is also expanded to 8.

Also, the configuration of the PHY header may be switched according to the frequency bandwidth and resource block width supported by the base station 101. For example, when the frequency bandwidth supported by the base station 101 is 80 MHz and the resource block width is 5 MHz, a total of 16 resource blocks are set by calculating “frequency bandwidth / resource block width”. If it is specified that the number of resource blocks and the number of User Positions are the same, User Position will also be a value between 0 and 15 (4 bits), and UP of RB [n] field (n is an integer between 1 and 16) The total number of bits is 64 (4 bits × 16) ((c) in FIG. 8). On the other hand, if the number of user blocks is different from the number of user blocks, such as the number of user blocks is 4, the total number of bits in the UP-of-RB [n] field (where n is an integer from 1 to 16) is 2 (2 bits x 16) ((d) of FIG. 8).

For each wireless terminal, the base station 101 matches the number of Group IDs, supported frequency bandwidth, resource block width, guard subcarrier information, resource block number, User Position number, and User Position number with the number of resource blocks. All or part of the information regarding whether or not the information may be notified to each wireless terminal. For the notification, the Group ID Management frame described above may be used, or a new frame defined separately may be used. Further, the Reserved bit of the existing frame may be used. In addition, when updating the notified information, the information may be notified again. Accordingly, each wireless terminal can grasp the configuration (field length, arrangement, etc.) of the PHY header transmitted from the base station 101 during OFDMA communication.

(Modification 2)
In the examples so far, the base station 101 uses the GID field and the UP of RB [n] field (where n is a natural number equal to or less than the number of resource blocks) to be a target of OFDMA communication and a resource block to be assigned to each radio terminal. However, it is also possible to notify using another method.

FIG. 9 shows an example of a PHY header that the base station 101 transmits in the downlink in this modification. The PHY header includes a GID field, a Pbit (Permutation bit) field, and a “Number of RBs field”. The PHY header in this modification can be applied to both the downlink and uplink OFDMA communications described above. In the case of uplink, the field of FIG. 9 is stored in the Poll frame.

In the GID field, the ID of the group subject to OFDMA communication is stored.

In the Pbit field, the User Position that is the starting point when assigning resource blocks in the “Number of RBs field” described later is set. For example, in the situation where the group information of FIG. 3 is notified to each wireless terminal, if “0” is set in the Pbit field, the resources in the order of UP0, UP1, UP2, UP3 in the “Number of RBs field” described later A block is allocated. Similarly, when the Pbit field is “1”, the order is UP1, UP2, UP3, UP0. When the Pbit field is “2”, the order is UP2, UP3, UP0, UP1, and the Pbit field is “3”. In this case, resource blocks are allocated in the order of UP3, UP0, UP1, and UP2.

As described above, in this modification, the base station 101 can change the order of the User Position to which the resource block is allocated by adjusting the value of the Pbit field. Note that the size of the Pbit field is determined according to the number of User 、 Positions, and when the User Position number is 4, it is 2 bits.

The number of resource blocks allocated to each User Position is set in the “Number of RBs field”. At this time, the User Position that is the starting point of the assignment is the User Position specified in the Pbit field. When the Pbit field is “1”, the number of resource blocks to be allocated to the wireless terminal corresponding to UP1 is set in “# of RBs (1) field”. Here, resource block allocation is performed from the lowest frequency to the highest frequency (when the number of RBs is 4, the order of RB1 to RB4).

For example, if “1” is set in the Pbit field and “2” is set in the “# of RBs” (1) field, two resource blocks RB1 and RB2 are allocated to the wireless terminal corresponding to UP1. In the subsequent “# of RBs (2) field”, the number of resource blocks allocated to the wireless terminal corresponding to UP2 is set. When two resource blocks (RB1 and RB2) are assigned to the UP1 wireless terminal, resource blocks after RB3 are assigned to UP2. If “# of RBs (2) field” is “0”, no resource block is assigned to UP2. The size of each field of “# of RBs (n)” is determined according to the number of resource blocks, and when the number of resource blocks is 4, it is 2 bits. Further, n of “# of RBs (n)” is determined according to the number of User Positions, and takes a value of 1 to 4 when the number of User Positions is 4.

A specific example when the base station 101 creates the PHY header will be described. Here, it is assumed that each wireless terminal has received a Group ID Management frame for its own device from the base station 101 and has grasped group information related to its own device among the group information shown in FIG. The base station 101 has data for the wireless terminal 202 and the wireless terminal 204, and transmits data to these wireless terminals by downlink OFDMA communication. Assume that base station 101 assigns RB1 and RB2 to radio terminal 204 and RB3 and RB4 to radio terminal 202 based on information such as the communication environment and the type and priority of data to be transmitted.

In this case, the base station 101 sets “1” (Group ID 1) to which the wireless terminals 202 and 204 belong as members in the GID field. As a result, it is possible to notify the wireless terminal 202 and the wireless terminal 204 that the own device is a target of OFDMA communication. The base station 101 can also select GID4 to which the wireless terminals 202 and 204 belong, but since GID4 includes more wireless terminals that are not OFDMA communication targets than GID1, In the example, GID1 is selected.

Next, by setting “3” in the Pbit field, the base station 101 sets the User Position that is the starting point when assigning resource blocks, that is, the User Position to which RB1 is assigned to UP3 (wireless terminal 204) of GID1. Set. Thereby, resource blocks can be assigned to RB1 to RB4 in the order of UP3, UP0, UP1, UP2 (that is, the order of wireless terminals 204, 201, 202, 203).

Finally, the base station 101 has “2” in the “# of RBs (1) field”, “0” in the “# of RBs (2) field”, “2” in the “# of RBs (3) field”, RB1 and RB2 (2 resource blocks) are allocated to the wireless terminal 204 and RB3 and RB4 (2 resource blocks) are allocated to the wireless terminal 202 by setting “0” in “# of RBs” (4) field respectively. be able to.

Each wireless terminal analyzes the PHY header transmitted from the base station 101 to determine whether or not its own device is the target of OFDMA communication, and if it is the target, the resource block assigned to the own device. Can be identified. In this modification, it is assumed that each wireless terminal previously knows the number of User Positions based on notification from the base station 101.

The method described in this modification can also be applied when the number of User Positions is greater than the number of resource blocks. FIG. 10 shows an example of group information when the number of User Positions is 10. The number of resource blocks is 4 (RB1 to RB4). In this case, the wireless terminal 101 sets “1” in the GID field, “0” in the Pbit field, and “1” in all the fields of “# of RBs (1) to (4)”. Can communicate with ~ 204 with OFDMA. Also, the base station 101 can perform OFDMA communication with the radio terminals 205 to 208 by changing only the Pbit field of the field values to “4”.

In the above description, allocation was performed from the lowest frequency to the highest frequency (in the case of 4 RBs, the order of RB1 to RB4). However, if each wireless terminal can grasp the order of the resource blocks to be allocated, other than this It may be the order. For example, the order from the highest frequency to the lowest frequency may be used, or any predetermined order may be used. Further, the base station 101 may determine the order and notify each wireless terminal.

(Modification 3)
In the above description, resource block-based OFDMA communication in which a plurality of radio terminals simultaneously use a plurality of resource blocks has been assumed. However, in this embodiment and the modification, a plurality of radio terminals simultaneously use a plurality of channels. It can also be used for channel-based multi-user multi-channel (MU-MC) communication. At that time, the base station 101 notifies the User Position and channel allocation information, and the above-described resource block can be replaced with a channel and read to make it possible to support MU-MC communication.

In the examples of FIGS. 6 to 8, the UP of RB [n] field (n is a natural number equal to or less than the number of resource blocks) is used to notify the resource block to be assigned to each wireless terminal. As long as 101 and each wireless terminal can understand, it can be set in an arbitrary order. It may be set in ascending order (RB1, RB2,...), Or may be set in descending order (RB [n], RB [n-1],...). Moreover, you may set in arbitrary orders. The base station 101 may notify each wireless terminal of the order in advance.

In the first embodiment, a mode in which communication is performed between the base station 101 and a plurality of wireless terminals has been described. However, the present invention can also be implemented when OFDMA communication is performed between wireless terminals without using the base station 101. is there. For example, this corresponds to the case where one of a plurality of wireless terminals is a transmitting side and two or more wireless terminals of the remaining wireless terminals are receiving sides and performs OFDMA communication. Note that Wi-Fi Direct is known as a standard for communication between wireless terminals without using a base station. When a wireless terminal supporting Wi-Fi Direct is enabled, it is recognized as a base station by other wireless terminals, and one-to-one or one-to-many connection is possible.

Also, the resource block width when performing OFDMA communication is not limited to 5 MHz. For example, it may be set to 2.5 MHz or 10 MHz. Further, the resource block width may be defined as a width including the guard subcarrier or may be defined as a width not including the guard subcarrier.

(Modification 4)
The base station 101 can determine a resource block to be allocated to each wireless terminal according to the communication environment. The base station 101 confirms the communication environment for each source block for a plurality of radio terminals to be subjected to OFDMA communication, and allocates to each radio terminal a resource block that provides the best communication environment except for the allocated resource block. be able to. Here, as an index indicating the communication environment, there are SNR (Signal to Noise Ratio), SINR (Signal to Interference plus Noise power Ratio) in each resource block, and the like. For example, when the wireless terminal with the highest SNR in RB1 is the wireless terminal 201, the base station 101 can assign RB1 to the wireless terminal 201.

Also, the base station 101 may perform resource block allocation using not only the communication environment for each resource block but also the channel communication environment. For example, when there are eight resource blocks with a 2.5 MHz width in a 20 MHz width channel, the base station 101 may use not only the SNR (SINR) for each resource block but also the SNR (SINR) of the 20 MHz width channel. . In this case, the base station 101 assigns a resource block having the highest SNR (SINR) to the wireless terminal having the lowest SNR (SINR) of the channel among a plurality of wireless terminals to be subjected to OFDMA communication. assign. Next, the resource block having the highest SNR (SINR) is allocated to the wireless terminal whose channel SNR (SINR) is the second lowest except for the allocated resource block. Thereafter, the same assignment process is repeated.

In addition, when using the allocation method in Modification 2 described above, the base station 101 allocates a resource block having the highest SNR (SINR) to the radio terminal having the lowest channel SNR (SINR). The Pbit field can be adjusted as required.

Note that the resource block allocation method described in this modification can be applied to both downlink and uplink OFDMA communication.

(Function block: Base station)
FIG. 11 is a block diagram showing a wireless communication apparatus mounted on base station 101. This wireless communication device includes antennas 5A to 5D, a wireless communication unit 505, and a communication control device 506, and controls wireless communication with a plurality of wireless terminals 201 to 210. Each operation of the base station 101 in the embodiment and the modification described above is executed by the wireless communication apparatus mounted on the base station 101.

The communication control device 506 includes a buffer 504 and a control unit 501. The wireless communication unit 505 includes a transmission unit 502 and a reception unit 503. The wireless communication apparatus includes four antennas 5A to 5D in this example, but may be configured to include one antenna. When a plurality of antennas are provided, a transmission unit and a reception unit may be provided for each antenna.

All or part of the digital processing of the wireless communication unit 505 and the communication control device 506 may be performed by software (program) that operates on a processor such as a CPU, may be performed by hardware, It may be done by both hardware. The base station 101 may include a processor that performs all or part of the digital processing of the wireless communication unit 505 and the communication control device 506.

The receiving unit 503 converts a signal received via the antennas 5A to 5D from a radio frequency (for example, a radio frequency such as 2.4 GHz or 5 GHz) to a baseband frequency, performs reception processing on the baseband signal, and converts the frame into a frame. get. The acquired frame is output to the control unit 501. The reception processing includes physical layer processing such as A / D conversion, demodulation processing, and physical header analysis.

The receiving unit 503 may include an analog filter and a digital filter, extract signals for all channel bands with an analog filter covering a plurality of channels, and extract a signal of a channel to be processed with the digital filter. Alternatively, the signal may be extracted with an analog filter corresponding only to the channel band to be processed. The operation band of the analog filter may be variable according to an instruction from the control unit 501, or may be an analog filter corresponding to only a band fixed in advance.

The control unit 501 controls frame reception via the reception unit 503 and frame transmission via the transmission unit 502. When receiving a frame, the control unit 501 analyzes the MAC header of the frame acquired by the receiving unit 503 and the like. If the control unit 501 determines from the MAC header analysis result that the received frame is a data frame, the control unit 501 can pass the data to the upper layer via the buffer 504. If it is determined that the received frame is a management frame or a control frame, communication control is performed according to the frame content. When transmitting a frame, the control unit 501 controls generation and transmission of a frame (management frame, control frame, data frame). For example, when data is input from the upper layer to the buffer 504, the control unit 501 generates a data frame storing this data in the Frame Body field, and outputs the data frame to the transmission unit 502.

The transmission unit 502 performs a desired physical layer process on the frame acquired from the control unit 501, and generates a physical packet. A radio frequency signal is generated by applying processing such as D / A conversion and frequency conversion to the physical packet, and is transmitted as a radio wave from the antennas 5A to 5D.

The transmission unit 502 may include an analog filter that extracts a signal in a desired band from a DA-converted frame signal. The operation band of the analog filter may be variable according to an instruction from the control unit 501, or may be an analog filter corresponding to only a band fixed in advance.

Note that the control unit 501 may execute digital processing in the reception unit 503 and the transmission unit 502. In this case, the communication control device 506 includes a part of the reception unit 503 and the transmission unit 502. A wireless communication device may be connected to a memory (not shown). The memory and buffer 504 may be a volatile memory such as DRAM or a non-volatile memory such as NAND or MRAM. Further, an SSD, a hard disk, or the like may be used.

(Function block: wireless terminal)
FIG. 12 is a block diagram showing a wireless communication device mounted on a wireless terminal. This wireless communication device includes antennas 6A to 6D, a wireless communication unit 605, and a communication control device 606, and controls wireless communication with the base station 101. Each operation of the wireless terminal in the embodiment and the modification described above is executed by a wireless communication device mounted on the wireless terminal.

The communication control device 606 includes a buffer 604 and a control unit 601. The wireless communication unit 605 includes a transmission unit 602 and a reception unit 603. The wireless communication apparatus includes four antennas 6A to 6D in this example, but may be configured to include one antenna. When a plurality of antennas are provided, a transmission unit and a reception unit may be provided for each antenna.

All or part of the digital processing of the wireless communication unit 605 and the communication control device 606 may be performed by software (program) that operates on a processor such as a CPU, may be performed by hardware, It may be done by both hardware. The base station 101 may include a processor that performs all or part of the digital processing of the wireless communication unit 605 and the communication control device 606.

The receiving unit 603 converts a signal received via the antennas 6A to 6D from a radio frequency to a baseband frequency, performs reception processing on the baseband signal, and acquires a frame. The acquired frame is output to the control unit 601. The reception processing includes physical layer processing such as A / D conversion, demodulation processing, and physical header analysis.

The receiving unit 603 may include an analog filter and a digital filter, extract signals for all channel bands with an analog filter that covers a plurality of channels, and extract signals of channels to be processed with the digital filter. Alternatively, the signal may be extracted with an analog filter corresponding only to the channel band to be processed. The operation band of the analog filter may be variable according to an instruction from the control unit 601, or an analog filter corresponding only to a band fixed in advance may be used.

The control unit 601 controls frame reception via the reception unit 603 and frame transmission via the transmission unit 602. When receiving the frame, the control unit 601 analyzes the MAC header of the frame acquired by the receiving unit 603 and the like. When it is determined from the MAC header analysis result that the received frame is a data frame, the control unit 601 can pass the data to the upper layer via the buffer 604. If it is determined that the received frame is a management frame or a control frame, communication control is performed according to the frame content. When transmitting a frame, the control unit 601 controls generation and transmission of a frame (management frame, control frame, data frame). For example, when data is input to the buffer 604 from an upper layer, the control unit 601 generates a data frame storing this data in the Frame Body field, and outputs the data frame to the transmission unit 602.

The transmission unit 602 performs a desired physical layer process on the frame acquired from the control unit 601, and generates a physical packet. A radio frequency signal is generated by applying processing such as D / A conversion and frequency conversion to the physical packet, and is transmitted as a radio wave from the antennas 6A to 6D.

The transmission unit 602 may include an analog filter that extracts a signal in a desired band from a DA-converted frame signal. The operation band of the analog filter may be variable according to an instruction from the control unit 601, or an analog filter corresponding only to a band fixed in advance may be used.

Note that the control unit 601 may execute digital processing in the reception unit 603 and the transmission unit 602. In this case, the communication control device 606 includes a part of the reception unit 603 and the transmission unit 602. A wireless communication device may be connected to a memory (not shown). The memory and buffer 604 may be a volatile memory such as DRAM or a non-volatile memory such as NAND or MRAM. Further, an SSD, a hard disk, or the like may be used.

(Flowchart: Downlink OFDMA communication)
FIG. 13 shows a flowchart of a basic operation example when the radio communication apparatus mounted on the base station 101 according to the present embodiment performs downlink OFDMA communication.

In step S1, the control unit 501 creates group information for the wireless terminals 201 to 210 that have established communication links with the own device. The control unit 501 can create group information using Group ID and User Position. The created group information can be stored in the buffer 604. Further, the group information may be stored in the memory.

In step S2, the control unit 501 notifies each wireless terminal of the group information created in step S1. The control unit 501 generates a Group ID Management frame to be transmitted to each wireless terminal and outputs it to the transmission unit 502. The transmission unit 502 generates a physical packet by performing desired physical layer processing on the Group ID Management frame. Then, the transmission unit 502 applies a process such as D / A conversion and frequency conversion to the physical packet to generate a radio frequency signal, and transmits it as a radio wave from the antenna.

In step S3, the control unit 501 determines a plurality of wireless terminals to be subjected to downlink OFDMA communication and resource blocks to be allocated to each wireless terminal. Here, the control unit 501 can check the data stored in the buffer 604 and the memory, and can set the destination wireless terminal of the stored data as a target of downlink OFDMA communication. In addition, the control unit 501 generates a MAC frame to be transmitted to a plurality of wireless terminals by OFDMA communication, and outputs the MAC frame to the transmission unit 502.

In step S4, the transmission unit 502 performs a desired physical layer process on the MAC frame acquired from the control unit 501, and generates a physical packet. Then, the transmission unit 502 applies a process such as D / A conversion and frequency conversion to the physical packet to generate a radio frequency signal, and transmits it as a radio wave from the antenna.

Here, the transmission unit 502 sets a desired value in the PHY header of the frame to be transmitted according to the information determined in step S3. Specifically, a desired value is stored in the GID field, UP of RB [n] field, Pbit field, Number of RBs field, and the like. Note that the control unit 501 may generate a PHY header and output the PHY header to the transmission unit 502. In addition, based on the resource block assignment determined in step S3, transmission section 502 transmits each MAC frame in a desired resource block.

The wireless communication apparatus of the base station 101 does not need to execute steps S1 and S2 for each downlink OFDMA communication. Once steps S1 and S2 are executed once, the group information can be notified to each wireless terminal. Therefore, the wireless communication apparatus of base station 101 thereafter performs steps of downlink OFDMA communication by omitting steps S1 and S2. be able to. The control unit 101 may execute step S1 again when updating the group information, and may execute S2 again when notifying the updated group information.

FIG. 14 shows a flowchart of a basic operation example when the radio communication apparatus mounted on the radio terminal according to the present embodiment performs downlink OFDMA communication.

In step S21, the wireless terminal receives group information from the base station 101. Specifically, the reception unit 603 converts a signal received via the antenna from a radio frequency to a baseband frequency, performs reception processing on the baseband signal, acquires a Group ID Management frame, and outputs the frame to the control unit 601. To do. The control unit 601 acquires group information about the own device from the Membership Status Array field and the User Position Array field stored in the Frame Body of the Group ID Management frame. The acquired group information can be held in the buffer 604 or the memory. Note that this step may be omitted when the base station 101 transmits group information once.

In step S22, the wireless terminal receives a frame transmitted from the base station 101 by downlink OFDMA communication. The receiving unit 603 converts a signal received via an antenna from a radio frequency to a baseband frequency, performs reception processing on the baseband signal, and acquires a frame.

In step S23, the receiving unit 603 analyzes the information stored in the PHY header of the received frame, and determines at least whether or not the own device is a target of downlink OFDMA communication. Specifically, it is determined whether or not the target is OFDMA communication using the group information acquired in step S21 and the GID field stored in the PHY header. The receiving unit 603 can read the group information from the buffer 604 or the memory. Here, the receiving unit 603 may read the group information directly from the buffer 604 and the memory, or may read the group information via the control unit 601.

Further, in step S23, the receiving unit 603 specifies a resource block to be used when the own apparatus is a target of OFDMA communication. The resource block can be identified by using the group information acquired in step S21 and information stored in the PHY header (GID field, UP of RB [n] field, Pbit field, Number of RBs field, etc.). The control unit 601 may execute the analysis of the PHY header in step S23.

In step S24, if the device itself is a target of OFDMA communication in step S23, the receiving unit 603 performs frame reception processing with the allocated resource block and extracts a MAC frame. The receiving unit 603 outputs the extracted MAC frame to the control unit 601.

In step S25, the control unit 601 analyzes the RA address of the acquired MAC frame, and determines whether the frame is a frame addressed to the own apparatus. If it is not addressed to its own device, the control unit 601 can discard the received frame.

(Flowchart: Uplink OFDMA communication)
FIG. 15 is a flowchart of a basic operation example when the radio communication apparatus of the base station 101 according to the present embodiment performs uplink OFDMA communication. Here, steps S31 and S32 are the same as steps S1 and S2 in FIG.

In step S33, the control unit 501 determines a plurality of wireless terminals to be subjected to uplink OFDMA communication and resource blocks to be allocated to each wireless terminal.

In step S34, the control unit 501 generates a Poll frame that triggers uplink OFDMA communication, and outputs the Poll frame to the transmission unit 502. The transmission unit 502 sets a desired value in the Poll frame according to the information determined in step S33. More specifically, desired values are set in the GID field, UP of RB [n] field, Pbit field, Number of RBs field, and the like. The control unit 501 may generate these fields and output them to the transmission unit 502.

The transmission unit 502 generates a physical packet by performing desired physical layer processing on the Poll frame. A radio frequency signal is generated by applying processing such as D / A conversion and frequency conversion to the physical packet, and is transmitted as a radio wave from the antenna.

In step S35, the receiving unit 503 receives frames transmitted from a plurality of wireless terminals after uplink time T1 by uplink OFDMA communication. At this time, the reception unit 503 can receive the MAC frame transmitted from each wireless terminal by performing reception processing for each resource block.

Note that the radio communication apparatus of the base station 101 does not need to execute steps S31 and S32 for each uplink OFDMA communication. Once steps S31 and S32 are executed, group information can be notified to each wireless terminal. Therefore, the wireless communication apparatus of base station 101 thereafter performs steps of SDMA and uplink OFDMA communication while omitting steps S31 and S32. be able to. Further, the control unit 101 may execute step S31 again when updating the group information, and may execute step S32 again when notifying the updated group information.

FIG. 16 is a flowchart of a basic operation example when the radio communication device of the radio terminal according to the present embodiment performs uplink OFDMA communication.

Step S41 is the same as step S21 in FIG.

In step S42, the wireless terminal receives the Poll frame transmitted from the base station 101. The receiving unit 603 converts a signal received via the antenna from a radio frequency to a baseband frequency, performs reception processing on the baseband signal, and receives a Poll frame.

In step S43, the receiving unit 603 analyzes the Poll frame, and determines whether or not the own device is a target of uplink OFDMA communication. Specifically, it is determined whether or not the target is OFDMA communication using the group information acquired in step S41 and the GID field of the Poll frame. The receiving unit 603 can acquire group information from the buffer 604 and the memory. Here, the reception unit 603 may directly read the group information from the buffer 604 and the memory, or may read the group information via the control unit 601.

In addition, the receiving unit 603 specifies a resource block to be used when the own apparatus is a target of OFDMA communication. The resource block can be specified using the group information acquired in step S41 and information stored in the Poll frame (GID field, UP of RB [n] field, Pbit field, Number of RBs field, etc.). The control unit 601 may execute the analysis of the Poll frame in step S43.

In step S44, the control unit 601 controls to transmit the frame to the base station 101 after a lapse of T1 time from the reception of the Poll frame when the own apparatus is the target of OFDMA communication in step S43. Specifically, control unit 601 generates a MAC frame addressed to base station 101 and outputs the MAC frame to transmitting unit 602. The transmission unit 602 performs a desired physical layer process on the acquired MAC frame to generate a physical packet. A radio frequency signal is generated by applying processing such as D / A conversion and frequency conversion to the physical packet, and is transmitted as a radio wave from the antenna. Here, the transmitting unit 602 transmits a physical packet using the resource block assigned to the own device identified in step S43.

The T1 time may be counted by the control unit 601 or the transmission unit 602.

(Second embodiment)
FIG. 17 is a functional block diagram of another example of the base station (access point) 101 according to the present embodiment. This access point includes a communication processing unit 401, a transmission unit 402, a reception unit 403, antennas 42A, 42B, 42C, and 42D, a network processing unit 404, a wired I / F 405, and a memory 406. . The access point 400 is connected to the server 407 via the wired I / F 405. The communication processing unit 401 has the same function as the control unit 501 (see FIG. 11) or the communication control device 506 described in the first embodiment. The transmission unit 402 and the reception unit 403 have functions similar to those of the transmission unit 502 and the reception unit 503 described in the first embodiment. The network processing unit 404 has the same function as the upper layer described in the first embodiment. Here, the communication processing unit 401 may internally have a buffer for exchanging data with the network processing unit 404. This buffer may be a volatile memory such as DRAM, or a non-volatile memory such as NAND or MRAM.

The network processing unit 404 controls data exchange with the communication processing unit 401, data writing / reading with the memory 406, and communication with the server 407 via the wired I / F 405. The network processing unit 404 may perform communication processing above the MAC layer such as TCP / IP and UDP / IP and processing of the application layer. The operation of the network processing unit may be performed by software (program) processing by a processor such as a CPU, may be performed by hardware, or may be performed by both software and hardware.

As an example, the communication processing unit 401 corresponds to a baseband integrated circuit, and the transmission unit 402 and the reception unit 403 correspond to an RF integrated circuit that transmits and receives a frame. The communication processing unit 401 and the network processing unit 404 may be configured by one integrated circuit (one chip). The digital domain processing part and the analog domain processing part of the transmission unit 402 and the reception unit 403 may be configured by different chips. Further, the communication processing unit 401 may execute communication processing at a higher level of the MAC layer such as TCP / IP and UDP / IP. In addition, the number of antennas is four here, but it is sufficient that at least one antenna is provided.

The memory 406 stores data received from the server 407, data received by the receiving unit 402, and the like. The memory 406 may be, for example, a volatile memory such as DRAM or a non-volatile memory such as NAND or MRAM. Further, it may be an SSD, HDD, SD card, eMMC, or the like. Memory 406 may be external to base station 101.

The wired I / F 405 transmits / receives data to / from the server 407. In this embodiment, communication with the server 407 is performed by wire, but communication with the server 407 may be performed wirelessly.

The server 407 is a communication device that receives a data transfer request for requesting data transmission and returns a response including the requested data. For example, an HTTP server (Web server), an FTP server, or the like is assumed. However, the present invention is not limited to this as long as it has a function of returning the requested data. A communication device operated by a user such as a PC or a smartphone may be used. In addition, the base station 101 may be communicated wirelessly.

When the STA belonging to the BSS of the base station 101 issues a data transfer request to the server 407, a packet related to the data transfer request is transmitted to the base station 101. The base station 101 receives this packet via the antennas 42A to 42D, and executes a physical layer process or the like by the receiving unit 403, and a MAC layer process or the like by the communication processing unit 401.

The network processing unit 404 analyzes the packet received from the communication processing unit 401. Specifically, the destination IP address, the destination port number, etc. are confirmed. When the packet data is a data transfer request such as an HTTP GET request, the network processing unit 404 determines that the data requested by the data transfer request (for example, data existing in the URL requested by the HTTP GET request) Whether it is cached (stored) in the memory 406 is confirmed. The memory 406 stores a table in which URLs (or reduced representations thereof, such as hash values or alternative identifiers) and data are associated with each other. Here, the fact that the data is cached in the memory 406 is expressed as the presence of cache data in the memory 406.

When the cache data does not exist in the memory 406, the network processing unit 404 transmits a data transfer request to the server 407 via the wired I / F 405. That is, the network processing unit 404 transmits a data transfer request to the server 407 on behalf of the STA. Specifically, the network processing unit 404 generates an HTTP request, performs protocol processing such as addition of a TCP / IP header, and passes the packet to the wired I / F 405. The wired I / F 405 transmits the received packet to the server 407.

The wired I / F 405 receives from the server 407 a packet that is a response to the data transfer request. The network processing unit 404 recognizes that the packet is addressed to the STA from the IP header of the packet received via the wired I / F 405, and passes the packet to the communication processing unit 401. The communication processing unit 401 performs MAC layer processing and the like on this packet, and the transmission unit 402 performs physical layer processing and the like, and transmits packets addressed to the STA from the antennas 42A to 42D. Here, the network processing unit 404 stores the data received from the server 407 as cache data in the memory 406 in association with the URL (or a reduced representation thereof).

When the cache data exists in the memory 406, the network processing unit 404 reads out the data requested by the data transfer request from the memory 406 and transmits this data to the communication processing unit 401. Specifically, an HTTP header or the like is added to the data read from the memory 406, protocol processing such as addition of a TCP / IP header is performed, and the packet is transmitted to the communication processing unit 401. At this time, as an example, the source IP address of the packet is set to the same IP address as the server, and the source port number is also set to the same port number as the server (the destination port number of the packet transmitted by the communication terminal). Therefore, when viewed from the STA, it looks as if it is communicating with the server 407. The communication processing unit 401 performs MAC layer processing and the like on this packet, and the transmission unit 402 performs physical layer processing and the like, and transmits packets addressed to the STA from the antennas 42A to 42D.

With such an operation, frequently accessed data responds based on the cache data stored in the memory 406, and traffic between the server 407 and the base station 101 can be reduced. Note that the operation of the network processing unit 404 is not limited to the operation of this embodiment. A general cache proxy that acquires data from the server 407 instead of the STA, caches the data in the memory 406, and responds to the data transfer request for the same data from the cache data in the memory 406. In other words, there is no problem with other operations.

The base station (access point) of this embodiment can be applied as the base station of the first embodiment. For example, the base station receives data transfer requests from a plurality of terminals in advance, and specifies a terminal in which data requested by the data transfer request is cached. The base station reads these data from the memory 406, generates data frames each including the read data, adds a physical header, and transmits the downlink data to these terminals by OFDMA (see FIG. 6). For a terminal whose data is not cached in the memory 406, the data requested by the data transfer request from the server 407 is acquired and cached in the memory 407. This operation may be performed independently of the wireless network communication on the terminal side. Here, it is assumed that the data to be transmitted to the terminal is data acquired from the server 407, but the present invention is not limited to this. As long as the data stored in the memory 406 is transmitted, the data acquired by any method may be used. Further, instead of transmitting the data cached in the memory 406, it is also possible to transmit information based on the cached data to the terminal via a data frame or a management frame. For example, information such as the data amount or data type of the cached data may be used. When transmitting this information, a request for transmitting the information may be acquired from the terminal, and the information may be transmitted in response to the request, or the base station may transmit the information without receiving such a request. May be.

In this embodiment, a base station having a cache function has been described. However, a terminal (STA) having a cache function can be realized with the same block configuration as in FIG. In this case, the wired I / F 405 may be omitted. The terminal of this embodiment can be applied as the terminal of the first embodiment. For example, the terminal (see FIG. 7 and the like) reads the data cached in the memory 406 and transmits a data frame including the read data (more specifically, a physical packet with a physical header added) to the base station. . The data may be data acquired from the server 407 or data acquired by another method. Further, instead of transmitting the data cached in the memory 406, it is also possible to transmit information based on the cached data to the base station via a data frame or a management frame. For example, information such as the data amount or data type of the cached data may be used. When transmitting this information, a request for transmitting the information may be acquired from the base station, and the information may be transmitted in response to the request, or the information may be transmitted without receiving such a request. Good. The base station may determine an uplink target terminal using this information. Or a base station may determine the terminal used as the object of downlink multiuser communication using this information. For example, a terminal having a data amount equal to or greater than a certain value, or a terminal having a data amount equal to or greater than a certain ratio with respect to the buffer size may be determined not to be selected as a downlink target terminal because it is determined that the buffer is small. In the case of a multi-hop network, a terminal has both a role of a terminal as a non-base station and a role as a base station. When the terminal operates as a base station, the above-described operation of the base station may be performed.

(Third embodiment)
FIG. 18 shows an example of the overall configuration of a terminal or a base station. This configuration example is an example, and the present embodiment is not limited to this. The terminal or base station includes one or a plurality of antennas 1 to n (n is an integer of 1 or more), a wireless LAN module 148, and a host system 149. The wireless LAN module 148 corresponds to the wireless communication device according to the first embodiment. The wireless LAN module 148 includes a host interface, and is connected to the host system 149 through the host interface. In addition to being connected to the host system 149 via a connection cable, the host system 149 may be directly connected. In addition, a configuration in which the wireless LAN module 148 is mounted on a substrate with solder or the like and is connected to the host system 149 via wiring on the substrate is also possible. The host system 149 communicates with an external device using the wireless LAN module 148 and the antennas 1 to n according to an arbitrary communication protocol. The communication protocol may include TCP / IP and higher layer protocols. Alternatively, TCP / IP may be installed in the wireless LAN module 148, and the host system 149 may execute only higher-layer protocols. In this case, the configuration of the host system 149 can be simplified. This terminal is, for example, mobile terminal, TV, digital camera, wearable device, tablet, smartphone, game device, network storage device, monitor, digital audio player, web camera, video camera, project, navigation system, external adapter, internal It may be an adapter, set top box, gateway, printer server, mobile access point, router, enterprise / service provider access point, portable device, handheld device, and the like.
FIG. 19 shows a hardware configuration example of the wireless LAN module. This configuration can be applied when the wireless communication apparatus is installed in either a non-base station terminal or a base station. That is, it can be applied as an example of a specific configuration of the wireless communication apparatus shown in FIG. In this configuration example, at least one antenna 247 is provided. When multiple antennas are provided, multiple sets of transmission systems (216, 222 to 225), reception systems (232 to 235), PLL242, crystal oscillator (reference signal source) 243 and switch 245 are arranged for each antenna. Each set may be connected to the control circuit 212. The PLL 242 or the crystal oscillator 243 or both correspond to the oscillator according to the present embodiment.

The wireless LAN module (wireless communication device) includes a baseband IC (Integrated Circuit) 211, an RF (Radio Frequency) IC221, a balun 225, a switch 245, and an antenna 247.

The baseband IC 211 includes a baseband circuit (control circuit) 212, a memory 213, a host interface 214, a CPU 215, a DAC (Digital to Analog Converter) 216, and an ADC (Analog to Digital Converter) 217.

Baseband IC211 and RF IC221 may be formed on the same substrate. Further, the baseband IC 211 and the RF IC 221 may be configured by one chip. Either one or both of the DAC 216 and the ADC 217 may be arranged in the RF IC 221 or may be arranged in another IC. Further, either or either one of the memory 213 and the CPU 215 may be arranged in an IC different from the baseband IC.

The memory 213 stores data exchanged with the host system. The memory 213 stores information notified to the terminal or base station, information notified from the terminal or base station, or both. The memory 213 may store a program necessary for the execution of the CPU 215, and may be used as a work area when the CPU 215 executes the program. The memory 213 may be a volatile memory such as SRAM or DRAM, or may be a non-volatile memory such as NAND or MRAM.

The host interface 214 is an interface for connecting to the host system. The interface can be anything such as UART, SPI, SDIO, USB, PCI Express.

The CPU 215 is a processor that controls the baseband circuit 212 by executing a program. The baseband circuit 212 mainly performs MAC layer processing and physical layer processing. The baseband circuit 212, the CPU 215, or both correspond to a communication control device that controls communication or a control unit that controls communication.

At least one of the baseband circuit 212 and the CPU 215 may include a clock generation unit that generates a clock, and the internal time may be managed by the clock generated by the clock generation unit.

The baseband circuit 212 adds a physical header to the frame to be transmitted as a physical layer process, encodes, encrypts, modulates, and so on. For example, two types of digital baseband signals (hereinafter, digital I signal and digital Q signal) Signal).

The DAC 216 DA converts the signal input from the baseband circuit 212. More specifically, the DAC 216 converts the digital I signal into an analog I signal, and converts the digital Q signal into an analog Q signal. Note that there may be a case where the signal is transmitted as it is without a quadrature modulation. In the case where a plurality of antennas are provided and one or more transmission signals are distributed and transmitted by the number of antennas, a number of DACs or the like corresponding to the number of antennas may be provided.

RF IC 221 is, for example, an RF analog IC or a high frequency IC, or both of them. The RF IC 221 includes a filter 222, a mixer 223, a preamplifier (PA) 224, a PLL (Phase Locked Loop) 242, a low noise amplifier (LNA), a balun 235, a mixer 233, and a filter 232. Some of these elements may be located on the baseband IC 211 or another IC. The filters 222 and 232 may be band pass filters or low pass filters. The RF IC 221 is coupled to the antenna 247 via the switch 245.

The filter 222 extracts a signal in a desired band from each of the analog I signal and the analog Q signal input from the DAC 216. The PLL 242 uses the oscillation signal input from the crystal oscillator 243 and divides or multiplies the oscillation signal or both, thereby generating a signal having a constant frequency synchronized with the phase of the input signal. The PLL 242 includes a VCO (Voltage Controlled Oscillator), and obtains a signal having the constant frequency by performing feedback control using the VCO based on the oscillation signal input from the crystal oscillator 243. The generated constant frequency signal is input to the mixer 223 and the mixer 233. The PLL 242 corresponds to an example of an oscillator that generates a signal having a constant frequency.

The mixer 223 up-converts the analog I signal and the analog Q signal that have passed through the filter 222 to a radio frequency by using a constant frequency signal supplied from the PLL 242. The preamplifier (PA) amplifies the radio frequency analog I signal and analog Q signal generated by the mixer 223 to a desired output power. The balun 225 is a converter for converting a balanced signal (differential signal) into an unbalanced signal (single-ended signal). The RF IC 221 handles balanced signals, but since the unbalanced signal is handled from the output of the RF IC 221 to the antenna 247, these signals are converted by the balun 225.

The switch 245 is connected to the balun 225 on the transmission side during transmission, and is connected to the balun 234 or RF IC 221 on the reception side during reception. The control of the switch 245 may be performed by the baseband IC 211 or the RF IC 221, or another circuit for controlling the switch 245 may exist, and the switch 245 may be controlled from the circuit.

The radio frequency analog I signal and analog Q signal amplified by the preamplifier 224 are balanced-unbalanced converted by the balun 225 and then radiated as radio waves from the antenna 247.

The antenna 247 may be a chip antenna, an antenna formed by wiring on a printed board, or an antenna formed by using a linear conductor element.

The LNA 234 in the RF IC 221 amplifies the signal received from the antenna 247 via the switch 245 to a level that can be demodulated while keeping the noise low. The balun 235 performs unbalance-balance conversion on the signal amplified by the low noise amplifier (LNA) 234. The mixer 233 down-converts the reception signal converted into the balanced signal by the balun 235 into a baseband using a signal having a constant frequency input from the PLL 242. More specifically, the mixer 233 has means for generating a carrier wave that is 90 ° out of phase with each other based on a signal having a constant frequency input from the PLL 242. Quadrature demodulation is performed using a carrier wave whose phase is shifted to generate an I (In-phase) signal having the same phase as the received signal and a Q (Quad-phase) signal having a phase delayed by 90 ° therefrom. The filter 232 extracts a signal having a desired frequency component from these I signal and Q signal. The I signal and Q signal extracted by the filter 232 are output from the RF IC 221 after the gain is adjusted.

ADC 217 in baseband IC211 AD converts the input signal from RF IC221. More specifically, the ADC 217 converts the I signal into a digital I signal, and converts the Q signal into a digital Q signal. There may be a case where only one system signal is received without performing quadrature demodulation.

When multiple antennas are provided, the number of ADCs corresponding to the number of antennas may be provided. Based on the digital I signal and the digital Q signal, the baseband circuit 212 performs physical layer processing such as demodulation processing, error correction code processing, and physical header processing to obtain a frame. The baseband circuit 212 performs MAC layer processing on the frame. The baseband circuit 212 may be configured to perform TCP / IP processing when TCP / IP is implemented.

(Fourth embodiment)
FIGS. 20A and 20B are perspective views of a wireless terminal according to the fourth embodiment, respectively. The wireless terminal in FIG. 20A is a notebook PC 301, and the wireless terminal in FIG. Each corresponds to one form of a wireless terminal (including a base station). The notebook PC 301 and the mobile terminal 321 are equipped with wireless communication devices 305 and 315, respectively. As the wireless communication devices 305 and 315, wireless communication devices mounted on the wireless terminals (including base stations) described so far can be used. A wireless terminal equipped with a wireless communication device is not limited to a notebook PC or a mobile terminal. For example, TV, digital camera, wearable device, tablet, smartphone, game device, network storage device, monitor, digital audio player, web camera, video camera, projector, navigation system, external adapter, internal adapter, set top box, gateway, It can also be mounted on a printer server, a mobile access point, a router, an enterprise / service provider access point, a portable device, a handheld device, a mobile body such as a car, and the like.

In addition, a wireless communication device mounted on a wireless terminal (including a base station) can be mounted on a memory card. FIG. 21 shows an example in which the wireless communication device is mounted on a memory card. The memory card 331 includes a wireless communication device 355 and a memory card main body 332. The memory card 331 uses a wireless communication device 335 for wireless communication with an external device. In FIG. 21, description of other elements in the memory card 331 (for example, a memory) is omitted.

(Fifth embodiment)
In the fifth embodiment, in addition to the configuration of the wireless communication apparatus according to any one of the first to fourth embodiments, a bus, a processor unit, and an external interface unit are provided. The processor unit and the external interface unit are connected to a memory (buffer) via a bus. Firmware operates in the processor unit. As described above, by configuring the firmware to be included in the wireless communication device, it is possible to easily change the function of the wireless communication device by rewriting the firmware. The processor unit on which the firmware operates may be the communication control device or the control unit according to the present embodiment, or a processor that performs a plurality of processes, or another processor that performs a process related to function expansion or change of the process. It may be. The processor unit on which the firmware operates may be provided in the base station and / or the wireless terminal according to the present embodiment. Alternatively, the processor unit may be provided in an integrated circuit in a wireless communication device mounted on a base station or an integrated circuit in a wireless communication device mounted on a wireless terminal.

(Sixth embodiment)
In the sixth embodiment, a clock generation unit is provided in addition to the configuration of the wireless communication apparatus according to any one of the first to fifth embodiments. The clock generation unit generates a clock and outputs the clock from the output terminal to the outside of the wireless communication device. Thus, the host side and the wireless communication apparatus side can be operated in synchronization by outputting the clock generated inside the wireless communication apparatus to the outside and operating the host side with the clock output to the outside. It becomes possible.

(Seventh embodiment)
The seventh embodiment includes a power supply unit, a power supply control unit, and a wireless power supply unit in addition to the configuration of the wireless communication apparatus according to any one of the first to sixth embodiments. The power supply control unit is connected to the power supply unit and the wireless power supply unit, and performs control to select a power supply to be supplied to the wireless communication device. As described above, by providing the wireless communication apparatus with the power supply, it is possible to perform a low power consumption operation by controlling the power supply.

(Eighth embodiment)
The eighth embodiment includes a SIM card in addition to the configuration of the wireless communication device according to any one of the first to seventh embodiments. The SIM card is connected to, for example, a communication control device or a control unit in the wireless communication device. As described above, the authentication process can be easily performed by providing the wireless communication apparatus with the SIM card.

(Ninth embodiment)
The ninth embodiment includes a moving image compression / decompression unit in addition to the configuration of the wireless communication apparatus according to any one of the first to seventh embodiments. The moving image compression / decompression unit is connected to the bus. As described above, by providing the wireless communication device with the moving image compression / decompression unit, it is possible to easily transmit the compressed moving image and expand the received compressed moving image.

(Tenth embodiment)
The tenth embodiment includes an LED unit in addition to the configuration of the wireless communication apparatus according to any one of the first to ninth embodiments. The LED unit is connected to, for example, at least one of a communication control device, a control unit, a transmission processing circuit, a reception processing circuit, and a control circuit. As described above, by providing the wireless communication device with the LED unit, it is possible to easily notify the user of the operation state of the wireless communication device.

(Eleventh embodiment)
The eleventh embodiment includes a vibrator unit in addition to the configuration of the wireless communication apparatus according to any one of the first to tenth embodiments. The vibrator unit is connected to, for example, at least one of a communication control device, a control unit, a transmission processing circuit, a reception processing circuit, and a control circuit. As described above, by providing the radio communication device with the vibrator unit, it is possible to easily notify the user of the operation state of the radio communication device.

(Twelfth embodiment)
The twelfth embodiment includes a display in addition to the configuration of the wireless communication device (the wireless communication device of the base station 101 or the wireless communication device of the wireless terminal) according to any one of the first to eleventh embodiments. The display may be connected to a communication control device or a control unit of the wireless communication device via a bus (not shown). Thus, it is possible to easily notify the user of the operation state of the wireless communication device by providing the display and displaying the operation state of the wireless communication device on the display.

(Thirteenth embodiment)
In this embodiment, [1] a frame type in a wireless communication system, [2] a method of disconnecting connections between wireless communication apparatuses, [3] an access method of a wireless LAN system, and [4] a frame interval of the wireless LAN will be described.

[1] Frame types in a communication system Generally, frames handled in a radio access protocol in a radio communication system are roughly classified into three types: a data frame, a management frame, and a control frame. These types are usually indicated by a header portion provided in common between frames. As a display method of the frame type, three types may be distinguished by one field, or may be distinguished by a combination of two fields. In the IEEE802.11 standard, the frame type is identified by two fields of Type and Subtype in the Frame Control field in the frame header portion of the MAC frame. The data frame, management frame, or control frame is roughly classified in the Type field, and the detailed classification in the roughly classified frame, for example, the Beacon frame in the management frame is identified in the Subtype field.

The management frame is a frame used for managing a physical communication link with another wireless communication device. For example, there are a frame used for setting communication with another wireless communication device, a frame for releasing a communication link (that is, disconnecting), and a frame related to a power saving operation in the wireless communication device. .

The data frame is a frame for transmitting data generated inside the wireless communication device to the other wireless communication device after establishing a physical communication link with the other wireless communication device. Data is generated in an upper layer of the present embodiment, for example, generated by a user operation.

The control frame is a frame used for control when a data frame is transmitted / received (exchanged) to / from another wireless communication apparatus. When the wireless communication apparatus receives a data frame or a management frame, the response frame transmitted for confirmation of delivery belongs to the control frame. The response frame is, for example, an ACK frame or a BlockAck frame. RTS frames and CTS frames are also control frames.

These three types of frames are sent through the antenna as physical packets after undergoing processing as needed in the physical layer. In the IEEE802.11 standard (including the above-mentioned extended standard such as IEEE Std 802.11ac-2013), there is an association process as one of the procedures for establishing a connection. The Association Request frame and the Association used in the process are also included. Since the Response frame is a management frame and the AssociationAsRequest frame and the Association Response frame are unicast management frames, the wireless terminal on the receiving side is requested to transmit an ACK frame that is a response frame. This ACK frame is a control frame as described above.

[2] Methods for disconnecting connections between wireless communication devices There are explicit and implicit methods for disconnecting (releasing) connections. As an explicit method, there is a method in which either one of wireless communication apparatuses that have established a connection transmits a frame for disconnection. In the IEEE802.11 standard, the Deauthentication frame corresponds to this and is classified as a management frame. Normally, when a wireless communication device that transmits a frame for disconnecting a connection transmits the frame, the wireless communication device that receives a frame for disconnecting a connection disconnects the connection when the frame is received. judge. After that, if it is a non-base station wireless terminal, it returns to the initial state in the communication phase, for example, the state of searching for a BSS to be connected. When the connection between a wireless communication base station and a wireless terminal is disconnected, for example, if the wireless communication base station has a connection management table for managing the wireless terminal that subscribes to its own BSS, from the connection management table Delete information related to the wireless terminal. For example, when an AID (Association ID) is assigned when a wireless communication base station grants a connection to each wireless terminal that joins its own BSS in the association process, it is associated with the AID of the wireless terminal that disconnected the connection. The stored information may be deleted, and the AID may be released and assigned to another newly joined wireless terminal.

On the other hand, as an implicit method, a frame transmission (transmission of a data frame and a management frame, or transmission of a response frame to a frame transmitted by the device itself) is detected from a wireless communication device of a connection partner with which a connection has been established. If not, it is determined whether the connection is disconnected. There is such a method in the situation where it is determined that the connection is disconnected as described above, such that the communication distance is away from the connection-destination wireless communication device, and the wireless signal cannot be received or decoded. This is because a wireless link cannot be secured. That is, it is impossible to expect reception of a frame for disconnecting the connection.

A timer is used as a specific example of determining disconnection by an implicit method. For example, when transmitting a data frame requesting a delivery confirmation response frame, a first timer that limits the retransmission period of the frame is started (for example, a retransmission timer for a data frame), and until the first timer expires (that is, If a delivery confirmation response frame is not received (until the desired retransmission period elapses), retransmission is performed. The first timer is stopped when a delivery confirmation response frame to the frame is received.

On the other hand, if the first timer expires without receiving the delivery confirmation response frame, for example, it is confirmed whether the other party's wireless communication device still exists (within the communication range) (in other words, the wireless link has been secured). And a second timer for limiting the retransmission period of the frame (for example, a retransmission timer for the management frame) is started at the same time. Similar to the first timer, the second timer also performs retransmission if it does not receive an acknowledgment frame for that frame until the second timer expires, and determines that the connection has been disconnected when the second timer expires . When it is determined that the connection has been disconnected, a frame for disconnecting the connection may be transmitted.

Or, when a frame is received from the wireless communication device of the connection partner, the third timer is started. Whenever a new frame is received from the wireless communication device of the connection partner, the third timer is stopped and started again from the initial value. When the third timer expires, a management frame is transmitted to check whether the other party's wireless communication device is still (within the communication range) (in other words, whether the wireless link has been secured) as described above. At the same time, a second timer (for example, a management frame retransmission timer) that limits the retransmission period of the frame is started. Also in this case, if the acknowledgment response frame to the frame is not received until the second timer expires, retransmission is performed, and if the second timer expires, it is determined that the connection has been disconnected. In this case as well, a frame for disconnecting the connection may be transmitted when it is determined that the connection has been disconnected. The latter management frame for confirming whether the wireless communication apparatus of the connection partner still exists may be different from the management frame in the former case. In the latter case, the timer for limiting the retransmission of the management frame is the same as that in the former case as the second timer here, but a different timer may be used.

[3] Wireless LAN system access method For example, there is a wireless LAN system that is assumed to communicate with or compete with a plurality of wireless communication devices. IEEE802.11 wireless LAN uses CSMA / CA (Carrier Sense Multiple Access with Carrier Avoidance) as the basic access method. In the method of grasping the transmission of a certain wireless communication device and performing transmission after a fixed time from the end of the transmission, the transmission is performed simultaneously by a plurality of wireless communication devices grasping the transmission of the wireless communication device, and as a result The radio signal collides and frame transmission fails. By grasping the transmission of a certain wireless communication device and waiting for a random time from the end of the transmission, the transmissions by a plurality of wireless communication devices that grasp the transmission of the wireless communication device are stochastically dispersed. Therefore, if there is one wireless communication device that has drawn the earliest time in the random time, the frame transmission of the wireless communication device is successful, and frame collision can be prevented. Since acquisition of transmission rights is fair among multiple wireless communication devices based on random values, the method employing Carrier Avoidance is a suitable method for sharing wireless media among multiple wireless communication devices. be able to.

[4] Wireless LAN Frame Interval The IEEE 802.11 wireless LAN frame interval will be described. Frame intervals used in IEEE 802.11 wireless LAN are distributed coordination function interframe space (DIFS), arbitration interframe space (AIFS), point coordination function interframe space (PIFS), short interframe space (SIFS), and extended interframe space (EIFS). There are 6 types of reduced interframe space (RIFS).

The definition of the frame interval is defined as a continuous period that should be opened after confirming the carrier sense idle before transmission in the IEEE802.11 wireless LAN, and the strict period from the previous frame is not discussed. Therefore, in the description of the IEEE802.11 wireless LAN system here, the definition follows. In the IEEE802.11 wireless LAN, the waiting time for random access based on CSMA / CA is the sum of a fixed time and a random time, and it can be said that such a definition is used to clarify the fixed time.

DIFS and AIFS are frame intervals used when attempting to start frame exchange during a contention period competing with other wireless communication devices based on CSMA / CA. DIFS is used when priority according to traffic type (Traffic Identifier: TID) is provided when priority is not distinguished by traffic type.

Since operations related to DIFS and AIFS are similar, the following description will be made mainly using AIFS. In the IEEE802.11 wireless LAN, access control including the start of frame exchange is performed at the MAC layer. Further, when QoS (Quality of Service) is supported when data is passed from an upper layer, the traffic type is notified together with the data, and the data is classified according to the priority at the time of access based on the traffic type. This access class is called an access category (AccessCategory: AC). Therefore, an AIFS value is provided for each access category.

PIFS is a frame interval for enabling access with priority over other competing wireless communication devices, and has a shorter period than both values of DIFS and AIFS. SIFS is a frame interval that can be used when a response control frame is transmitted or when frame exchange is continued in a burst after acquiring the access right. EIFS is a frame interval that is triggered when frame reception fails (it is determined that the received frame is an error).

RIFS is a frame interval that can be used when a plurality of frames are continuously transmitted to the same wireless communication device in bursts after acquiring the access right. While using RIFS, from the wireless communication device of the transmission partner Do not request a response frame.

Here, FIG. 22 shows an example of a frame exchange during a contention period based on random access in the IEEE802.11 wireless LAN.

Assume that when a transmission request for a data frame (W_DATA1) is generated in a certain wireless communication device, it is recognized that the medium is busy (busy medium) as a result of carrier sense. In this case, the AIFS is fixed for a fixed time after the carrier sense becomes idle, and then the data frame W_DATA1 is transmitted to the communication partner when the random time (random 時間 backoff) is available. As a result of carrier sense, if it is recognized that the medium is not busy, that is, the medium is idle, a fixed time AIFS is released from the time when carrier sense is started, and data frame W_DATA1 is transmitted to the other party. Send to.

ラ ン ダ ム Random time is obtained by multiplying a pseudo-random integer derived from uniform distribution between contention windows (Contention Window: CW) given by an integer from 0 to slot time. Here, the CW multiplied by the slot time is called the CW time width. The initial value of CW is given by CWmin, and every time retransmission is performed, the value of CW is increased until it reaches CWmax. Both CWmin and CWmax have values for each access category similar to AIFS. In the wireless communication device that is the destination of W_DATA1, if the data frame is successfully received and the data frame is a frame that requests transmission of a response frame, the physical packet containing the data frame is completely occupied on the wireless medium. A response frame (W_ACK1) is transmitted after SIFS. The wireless communication apparatus that has transmitted W_DATA1 transmits the next frame (for example, W_DATA2) after SIFS from the time when the physical packet containing W_ACK1 is occupied on the wireless medium if it is within the transmission burst time limit when W_ACK1 is received. be able to.

AIFS, DIFS, PIFS, and EIFS are functions of SIFS and slot time. SIFS and slot time are specified for each physical layer. Also, parameters that have values for each access category, such as AIFS, CWmin, and CWmax, can be set for each communication group (Basic Service Set (BSS) in IEEE802.11 wireless LAN), but default values are set. .

For example, in the IEEE802.11ac standard formulation, SIFS is 16 μs and slot time is 9 μs, so that PIFS is 25 μs, DIFS is 34 μs, AIFS access category is background (AC_BK) frame interval is default value is 79 μs, The default frame interval for BEST EFFORT (AC_BE) is 43μs, the frame interval for VIDEO (AC_VI) and VOICE (AC_VO) is 34μs, and the default values for CWmin and CWmax are 31 and 1023 for AC_BK and AC_BE, respectively. Suppose AC_VI is 15 and 31, and AC_VO is 7 and 15. Note that EIFS is basically the sum of the time lengths of response frames in the case of transmission at SIFS, DIFS, and the slowest required physical rate. In wireless communication devices that can efficiently handle EIFS, the occupation time length of the physical packet that carries the response frame to the physical packet that triggered EIFS is estimated, and the sum of SIFS, DIFS, and the estimated time may be used. it can.

The terms used in this embodiment should be interpreted widely. For example, the term “processor” may include general purpose processors, central processing units (CPUs), microprocessors, digital signal processors (DSPs), controllers, microcontrollers, state machines, and the like. In some situations, a “processor” may refer to an application specific integrated circuit, a field programmable gate array (FPGA), a programmable logic circuit (PLD), or the like. “Processor” may refer to a combination of processing units such as a plurality of microprocessors, a combination of a DSP and a microprocessor, and one or more microprocessors that cooperate with a DSP core.

As another example, the term “memory (buffer)” may encompass any electronic component capable of storing electronic information. “Memory (buffer)” means random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable PROM (EEPROM) Non-volatile random access memory (NVRAM), flash memory, magnetic or optical data storage, which can be read by a processor. If the processor reads and / or writes information to the memory, the memory can be said to be in electrical communication with the processor. The memory may be integrated into the processor, which again can be said to be in electrical communication with the processor.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

101: Base station (AP)
201-210: Wireless terminal (STA)
501, 601: Control unit
502, 602: Transmitter
503, 603: Receiver
504, 604: Buffer
505, 605: Wireless communication unit
506, 606: Communication control device
5A, 5D, 6A, 6D, 1, N: Antenna
111: Baseband
121: RF part
122: Transmitter circuit
123: Receiver circuit
112: Control circuit
113: Transmission processing circuit
114: Reception processing circuit
115, 116: DA converter circuit
117, 118: AD converter circuit
148: Wireless LAN module
149: Host system
211: Baseband IC
213: Memory
214: Host interface
215: CPU
216: DAC
217: ADC
221: RF IC
222, 232: Filter
223, 233: Mixer
224, 234: Amplifier
225, 235: Balun
242: PLL
243: Crystal oscillator
247: Antenna
245: Switch
301: Notebook PC
305, 315, 355: Wireless communication device
321: Mobile terminal
331: Memory card
332: Memory card body
42A, 42B, 42C, 42D: Antenna
401: Communication processing unit
402: Transmitter
403: Receiver
404: Network processing section
405: Wired I / F
406: Memory

Claims (48)

1. At least one antenna,
   A wireless communication unit connected to the antenna for transmitting and receiving frames;
   A wireless terminal comprising a control unit for controlling the wireless communication unit,
   The control unit includes a first group to which a plurality of radio terminals belong, a second group to which a plurality of radio terminals belong, identification information of each radio terminal belonging to the first group, and each radio terminal belonging to the second group Transmitting the first frame including at least the second information related to the first wireless terminal among the first information consisting of the identification information, via the wireless communication unit,
   After the transmission of the first frame, to specify information specifying the first group to be subjected to OFDMA (Orthogonal Frequency Division Multiple Access) communication, and resource blocks to be allocated to the plurality of wireless terminals belonging to the first group A wireless terminal that controls to transmit, via the wireless communication unit, a second frame that includes third information including the above information.
2. 2. The wireless terminal according to claim 1, wherein the second frame includes data to be transmitted to the plurality of wireless terminals belonging to the first group.
3. The control unit performs control so that a plurality of frames transmitted from the plurality of wireless terminals belonging to the first group are received via the wireless communication unit after a predetermined time has elapsed since the transmission of the second frame. Item 1. A wireless terminal according to Item 1.
4. 4. The wireless terminal according to claim 1, wherein in the first information, the same identification information is given to a plurality of wireless terminals.
5. 5. The information for specifying the resource block in the third information is information that associates the resource block with identification information of the plurality of wireless terminals belonging to the first group. The wireless terminal described in 1.
6. Information for identifying the resource blocks in the third information is information for identifying the order in which the resource blocks are allocated in the plurality of wireless terminals belonging to the first group, and resources allocated according to the order 5. The wireless terminal according to claim 1, further comprising information for specifying the number of blocks.
7. The wireless terminal according to any one of claims 1 to 6, wherein the identification information is User Position.
8. The wireless terminal according to any one of claims 1 to 7, wherein the third information is stored in a PHY header of the second frame.
9. The radio terminal according to any one of claims 1 to 8, wherein the number of bits of the third information in the second frame varies according to a frequency band used by the radio terminal and a width of the resource block.
10. 10. The radio terminal according to claim 1, wherein the resource block includes one or a plurality of subcarriers.
11. The wireless terminal according to any one of claims 1 to 10, wherein the control unit controls communication in accordance with the IEEE 802.11 standard.
12. At least one antenna,
    A wireless communication unit connected to the antenna for transmitting and receiving frames;
    A wireless terminal comprising a control unit for controlling the wireless communication unit,
    The control unit receives a first frame including information identifying a first group to which the device belongs and identification information of the device in the first group via a wireless communication unit,
    After receiving the first frame, information for specifying the first group to be subjected to OFDMA (Orthogonal Frequency Division Multiple Access) communication and resource blocks to be assigned to a plurality of wireless terminals belonging to the first group Receiving the second frame including the second information consisting of information via the wireless communication unit,
    A wireless terminal that controls the OFDMA communication using the first and second information.
13. 13. The wireless terminal according to claim 12, wherein the control unit specifies a resource block assigned to the own device using the first and second information.
14. The second frame includes data to be transmitted to the plurality of wireless terminals belonging to the first group;
    The control unit refers to an address included in data received in a resource block assigned to the own device, and determines whether the received data is transmitted to the own device. 13. The wireless terminal according to 13.
15. The control unit controls to transmit a third frame via the wireless communication unit using a resource block allocated to the own device after a predetermined time has elapsed since the reception of the second frame. 13. The wireless terminal according to 13.
16. 16. The information for specifying the resource block in the second information is information that associates the resource block with identification information of the plurality of wireless terminals belonging to the first group. The wireless terminal described in 1.
17. Information for identifying the resource blocks in the second information is information for identifying the order in which the resource blocks are allocated in the plurality of wireless terminals belonging to the first group, and resources allocated according to the order 16. The radio terminal according to claim 12, comprising information for specifying the number of blocks.
18. The wireless terminal according to any one of claims 12 to 17, wherein the identification information is User Position.
19. The wireless terminal according to any one of claims 12 to 18, wherein the second information is stored in a PHY header of the second frame.
20. 20. The radio terminal according to any one of claims 12 to 19, wherein the resource block includes one or a plurality of subcarriers.
21. The wireless terminal according to any one of claims 12 to 20, wherein the control unit controls communication in accordance with the IEEE 802.11 standard.
22. A wireless communication method using a wireless terminal,
    A first group to which a plurality of wireless terminals belong, a second group to which a plurality of wireless terminals belong, identification information of each wireless terminal belonging to the first group, and identification information of each wireless terminal belonging to the second group Transmitting the first frame including at least the second information about the first wireless terminal among the first information
    After the transmission of the first frame, to specify information specifying the first group to be subjected to OFDMA (Orthogonal Frequency Division Multiple Access) communication, and resource blocks to be allocated to the plurality of wireless terminals belonging to the first group A wireless communication method for transmitting a second frame including third information consisting of the above information.
23. A wireless communication method using a wireless terminal,
    Receiving a first frame including first information including information identifying a first group to which the own device belongs and identification information of the own device in the first group;
    After receiving the first frame, information for specifying the first group to be subjected to OFDMA (Orthogonal Frequency Division Multiple Access) communication and resource blocks to be assigned to a plurality of wireless terminals belonging to the first group Receiving a second frame including second information consisting of information,
    A wireless communication method for controlling the OFDMA communication using the first and second information.
24. A first group to which a plurality of wireless terminals belong, a second group to which a plurality of wireless terminals belong, identification information of each wireless terminal belonging to the first group, and identification information of each wireless terminal belonging to the second group Transmitting the first frame including at least the second information about the first wireless terminal among the first information
    After the transmission of the first frame, to specify information specifying the first group to be subjected to OFDMA (Orthogonal Frequency Division Multiple Access) communication, and resource blocks to be allocated to the plurality of wireless terminals belonging to the first group An integrated circuit for wireless communication, comprising: a baseband integrated circuit that controls to transmit a second frame that includes third information consisting of the above information.
25. 25. The wireless communication integrated circuit according to claim 24, wherein the second frame includes data to be transmitted to the plurality of wireless terminals belonging to the first group.
26. 25. The radio according to claim 24, wherein the baseband integrated circuit controls to receive a plurality of frames transmitted from the plurality of radio terminals belonging to the first group after a predetermined time has elapsed since the transmission of the second frame. Integrated circuit for communication.
27. 27. The wireless communication integrated circuit according to claim 24, wherein the same identification information is given to a plurality of wireless terminals in the first information.
28. 28. The information for specifying the resource block in the third information is information associating the resource block with identification information of the plurality of wireless terminals belonging to the first group. An integrated circuit for wireless communication according to 1.
29. Information for identifying the resource blocks in the third information is information for identifying the order in which the resource blocks are allocated in the plurality of wireless terminals belonging to the first group, and resources allocated according to the order The integrated circuit for wireless communication according to any one of claims 24 to 27, comprising information for specifying the number of blocks.
30. 30. The integrated circuit for wireless communication according to any one of claims 24 to 29, wherein the identification information is User Position.
31. 31. The wireless communication integrated circuit according to claim 24, wherein the third information is stored in a PHY header of the second frame.
32. 32. The wireless communication integrated circuit according to claim 24, wherein the number of bits of the third information in the second frame varies depending on a frequency band to be used and a width of the resource block.
33. 33. The wireless communication integrated circuit according to claim 24, wherein the resource block includes one or a plurality of subcarriers.
34. 34. The wireless communication integrated circuit according to claim 24, wherein the baseband integrated circuit controls communication in accordance with IEEE802.11 standard.
35. Further comprising an RF integrated circuit,
    The baseband integrated circuit DA converts the first and second frames,
    35. The wireless communication integrated circuit according to claim 24, wherein the RF integrated circuit up-converts the first and second frames after DA conversion to a radio frequency.
36. 36. The wireless communication integrated circuit according to claim 35, wherein the baseband integrated circuit and the RF integrated circuit are configured as one integrated circuit.
37. STA
    Receiving a first frame including first information including information identifying a first group to which the own device belongs and identification information of the own device in the first group;
    Second information consisting of information for specifying the first group to be subjected to OFDMA (Orthogonal Frequency Division Multiple Access) communication and information for specifying resource blocks to be allocated to a plurality of wireless terminals belonging to the first group. Receiving a second frame containing,
    An integrated circuit for wireless communication, comprising: a baseband integrated circuit that controls the OFDMA communication using the first and second information.
38. 38. The wireless communication integrated circuit according to claim 37, wherein the baseband integrated circuit uses the first and second information to identify a resource block assigned to the baseband integrated circuit.
39. The second frame includes data to be transmitted to the plurality of wireless terminals belonging to the first group;
    The baseband integrated circuit refers to an address included in data received in a resource block allocated to the own device, and determines whether the received data is transmitted to the own device. 39. An integrated circuit for wireless communication according to Item 38.
40. 39. The radio communication according to claim 38, wherein the baseband integrated circuit controls to transmit a third frame using a resource block allocated to the own device after a predetermined time has elapsed since the reception of the second frame. Integrated circuit.
41. 41. The information for specifying the resource block in the second information is information associating the resource block with identification information of the plurality of wireless terminals belonging to the first group. An integrated circuit for wireless communication according to 1.
42. Information for identifying the resource blocks in the second information is information for identifying the order in which the resource blocks are allocated in the plurality of wireless terminals belonging to the first group, and resources allocated according to the order 41. The integrated circuit for wireless communication according to claim 37, comprising information for specifying the number of blocks.
43. 43. The wireless communication integrated circuit according to claim 37, wherein the identification information is User Position.
44. 44. The wireless communication integrated circuit according to claim 37, wherein the second information is stored in a PHY header of the second frame.
45. 45. The wireless communication integrated circuit according to claim 37, wherein the resource block includes one or a plurality of subcarriers.
46. The wireless communication integrated circuit according to any one of claims 37 to 45, wherein the baseband integrated circuit controls communication in accordance with the IEEE 802.11 standard.
47. Further comprising an RF integrated circuit,
    The RF integrated circuit down-converts the first and second frames to a baseband frequency,
    47. The wireless communication integrated circuit according to claim 37, wherein the baseband integrated circuit performs AD conversion on the first and second frames after down-conversion.
48. 48. The wireless communication integrated circuit according to claim 47, wherein the baseband integrated circuit and the RF integrated circuit are constituted by one integrated circuit.

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