JP7686380B2 - COMMUNICATION DEVICE, CONTROL METHOD, AND PROGRAM - Google Patents

Description

The present invention relates to a communication device capable of aggregating MAC (Media Access Control) frames.

Wireless LAN standards (IEEE802.11n and ac) prescribe A-MSDU (Aggregation-MAC Service Data Unit), which improves communication speeds by bundling MAC frames to increase data transmission efficiency. By aggregating MAC frames using A-MSDU, it is possible to reduce the time required by the protocol, such as the transmission waiting time and ACK waiting time for the data transmission period, and improve communication speeds.

For example, Patent Document 1 discloses a technique for determining the maximum frame length while adhering to the transmission time constraints stipulated in the standard, and combining data frames within that range to improve throughput.

On the other hand, to implement A-MSDU, the MAC frames generated by the upper layer protocol stack at the time of transmission must be concatenated in the wireless driver according to the A-MSDU frame format. In a typical implementation, the MAC frames generated by the protocol stack are put into a queue, and the wireless driver takes them out of the queue, concatenates a preset number of MAC frames, adds a wireless header to generate a wireless communication frame, and transfers it to the wireless device. Also, when performing wireless communication with multiple destinations, multiple queues are prepared and MAC frames are concatenated for each destination.

JP 2009-278542 A

However, in embedded products, the memory capacity available is small, so having a queue for each of multiple destinations can lead to memory resource shortages. On the other hand, when achieving aggregation with a small number of queues, MAC frames for multiple destinations can be mixed in the queue, preventing proper aggregation and causing a risk of reduced throughput.

In consideration of the above-mentioned problems, the present invention aims to optimize aggregation to multiple destinations while suppressing an increase in memory resources.

A communication device according to one aspect of the present invention is a communication device, comprising: a management unit that uses a first memory area to manage information of a structure that stores data corresponding to a MAC (Media Access Control) frame; and a FIFO (First In First Out) storage unit that stores information of a structure that stores data corresponding to a MAC (Media Access Control) frame. a transmission queue having a structure of a destination MAC address of a MAC frame corresponding to the newly generated structure and an upper limit size of an aggregation , determining whether to process the data by a first process of inserting address information for accessing a memory address of a structure newly generated as a management target by the management means into the tail of the transmission queue, or to process the data by a second process of managing the data in association with a structure corresponding to a MAC frame already inserted into the transmission queue without inserting address information into the transmission queue, using at least information on a destination MAC address of a MAC frame corresponding to the newly generated structure and an upper limit size of an aggregation; an inserting means for inserting address information for accessing a memory address of the newly generated structure into the tail of the transmission queue in a transmission waiting state based on the address information stored in the transmission queue, and a transfer control means for transferring a wireless frame via one of an interface of a USB (Universal Serial Bus) or a USB (Interconnect-Express) to a wireless control unit connected to a host system of the communication device, the transfer control means determining that the data is to be processed by the first process of putting address information for accessing a memory address of a newly generated structure as a target for management by the management means, into the tail of the transmission queue, in accordance with a determination that destination MAC address information of a MAC frame corresponding to a newly generated structure does not match destination MAC address information of a MAC frame corresponding to a structure corresponding to any of address information put into the transmission queue in a waiting state for transmission, and determining that the data is to be processed by the first process of putting address information for accessing a memory address of a newly generated structure as a target for management by the management means, into the tail of the transmission queue, in accordance with a determination that destination MAC address information of a MAC frame corresponding to a newly generated structure matches destination MAC address information of a MAC frame corresponding to a structure corresponding to any of address information put into the transmission queue in a waiting state for transmission, and and when it is determined that the MAC frame corresponding to the newly generated structure can be linked with the MAC frame already put into the transmission queue, the determination means determines to process the data by the second process of managing the data in association with the structure corresponding to the MAC frame already put into the transmission queue, without putting address information for accessing a memory address of a structure newly generated as a target for management by the management means into the transmission queue, and when it is determined that destination MAC address information of the MAC frame corresponding to the newly generated structure matches destination MAC address information of the MAC frame corresponding to a structure corresponding to any of the address information put into the transmission queue in a transmission waiting state, but the MAC frame indicated by the structure corresponding to the address information already put into the transmission queue and the MAC frame corresponding to the newly generated structure cannot be linked within an upper limit size of the aggregation, the determination means determines to process the data by the first process of putting address information for accessing a memory address of a structure newly generated as a target for management by the management means into the tail of the transmission queue, and when it is determined that the MAC frame indicated by the structure corresponding to the address information already put into the transmission queue cannot be linked with the MAC frame corresponding to the newly generated structure within an upper limit size of the aggregation, the determination means When it is determined that the data should be processed by the second process of managing the data in association with a structure corresponding to a MAC frame already put into the transmission queue without putting address information for accessing a memory address of a structure that has been put into the transmission queue and is equal to or smaller than the upper limit size, the management means performs a management process of linking the newly generated structure with a structure that corresponds to the address information already put into the transmission queue and is equal to or smaller than the upper limit size, and when it is determined by the determination means to proceed to the first process of putting address information for accessing a memory address of a structure newly generated as a target for management by the management means into the tail of the transmission queue, the putting means performs a process of putting the address information of the newly generated structure managed in a first memory area into the tail of the transmission queue, and when it is determined that the data should be processed by the second process of managing the data in association with a structure corresponding to a MAC frame already put into the transmission queue without putting address information for accessing a memory address of a structure that has been put into the transmission queue and is equal to or smaller than the upper limit size, the putting means and when another structure or structures are linked to the referenced structure, the transfer control means performs a process of aggregating a MAC frame specified by the referenced structure with one or more MAC frames specified by the other one or more linked structures, thereby controlling the aggregated wireless frame to be transferred to the wireless control unit, while when another structure is not linked to the referenced structure, the transfer control means does not perform a process of aggregation, and controls the transfer of a wireless frame including one MAC frame corresponding to the referenced structure that has not been aggregated, to the wireless control unit. When a plurality of pieces of address information are stored in the transmission queue in a waiting state for transmission, the transfer control means, which has determined to transfer the data to the wireless control unit, dequeues address information in order from the transmission queue of the FIFO structure, and controls the transfer of the generated plurality of wireless frames to the wireless control unit.

According to the present invention, it is possible to optimize aggregation to multiple destinations while suppressing the increase in memory resources.

FIG. 1 is a block diagram showing an example of the configuration of a communication network according to an embodiment. FIG. 1 is a block diagram showing an example of the configuration of a communication device according to an embodiment. 5 is a flowchart showing an aggregation process of a wireless driver according to the embodiment. FIG. 2 is a diagram showing a packet management structure according to an embodiment. FIG. 4 is a diagram showing an example of transmission queue and list management according to the embodiment. FIG. 4 is a diagram showing an aggregation processing sequence of a wireless driver according to the embodiment.

The following describes in detail the embodiments of the present invention with reference to the attached drawings. Note that the following embodiments do not limit the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the present invention. The configuration of the embodiments may be modified or changed as appropriate depending on the specifications of the device to which the present invention is applied and various conditions (conditions of use, environment of use, etc.). The technical scope of the present invention is determined by the claims, and is not limited by the individual embodiments below.

FIG. 1 is a block diagram illustrating an example of the configuration of a communication network according to an embodiment.
In FIG. 1, the communication system 11 includes communication devices 1 to 4. In the example of FIG. 1, the communication device 1 is an access point, and the communication devices 2 to 4 are stations. The communication devices 1 to 4 are devices equipped with communication functions such as a camera, a printer, a tablet, and a PC (Personal Computer). In this case, the communication system 11 can configure a wireless network in infrastructure mode. The infrastructure mode is one of the operation modes of a wireless LAN defined by IEEE 802.11. In the infrastructure mode, communication between stations is performed via an access point. For example, in the infrastructure mode, a video image captured by the camera, which is the communication device 2, can be transmitted to the communication devices 3 and 4 via the communication device 1, and can be displayed on multiple displays, which are the communication devices 3 and 4. Alternatively, content edited by the tablet, which is the communication device 2, can be transmitted to the communication devices 3 and 4 via the communication device 1, and can be printed by multiple printers, which are the communication devices 3 and 4, according to the purpose.

Communication device 2 transmits video or print data as wireless packets to communication devices 3 and 4 via communication device 1. At this time, communication device 1 handles the wireless packets of each of communication devices 3 and 4 simultaneously, making aggregation processing more efficient and improving communication speed. For example, communication device 1 can improve communication speed by transmitting wireless packets of the maximum allowable aggregation size to each of communication devices 3 and 4.

Furthermore, communication device 2 can transmit packets at the maximum aggregation size for each destination so that communication device 1 can efficiently transmit aggregated packets to each of communication devices 3 and 4. Here, the maximum aggregation size allowed by each of communication devices 1 to 4 is determined in advance by the device specifications and communication link method. For example, when connecting using IEEE802.11ac as the communication link method, the maximum aggregation size of A-MSDU is 10K bytes, and when using IEEE802.11n, the maximum aggregation size is 8K bytes.

A wireless link 12 is established between communication devices 1 and 2, a wireless link 13 is established between communication devices 1 and 3, and a wireless link 14 is established between communication devices 1 and 4. At this time, each communication device 1 to 4 can determine the maximum aggregation size in wireless links 12 to 14 by exchanging capabilities in advance. For example, wireless links 12 and 13 are connected by IEEE802.11ac, and wireless link 14 is connected by IEEE802.11n. However, communication device 4 is limited in specifications to support aggregation up to 6K bytes. In this case, each communication device 1 and 2 has a table for managing the maximum aggregation size for each destination, and performs aggregation of up to 10K bytes when the destination is communication device 3, and performs aggregation of up to 6K bytes when the destination is communication device 4.

Fig. 2 is a block diagram showing an example of the configuration of a communication device according to an embodiment. Note that Fig. 2 takes the communication device 1 in Fig. 1 as an example, but the communication devices 2 to 4 can also be configured in the same way.
Of the functional modules of the communication device 1 shown in FIG. 2, the functions realized by software are stored in a memory such as a ROM (Read Only Memory) or the like, in which a program for providing the function of each functional module is stored. Then, the program is read into a RAM (Random Access Memory) and executed by a CPU (Central Processing Unit), thereby realizing the functions. For the functions realized by hardware, for example, a specific compiler may be used to automatically generate a dedicated circuit on the FPGA from a program for realizing the function of each functional module. FPGA is an abbreviation for Field Programmable Gate Array. Also, a gate array circuit may be formed in the same manner as the FPGA, and may be realized as hardware. Also, it may be realized by an ASIC (Application Specific Integrated Circuit). Note that the functional block configuration shown in FIG. 2 is just one example, and multiple functional blocks may be configured to form one functional block, or any functional block may be divided into blocks performing multiple functions.

In FIG. 2, the communication device 1 includes a CPU 21, an on-chip memory 22, a main memory 23, and a wireless control unit 24. The CPU 21, the on-chip memory 22, the main memory 23, and the wireless control unit 24 are connected to each other via a system bus 25. The system bus 25 is a transfer path for various data.

The CPU 21 controls each hardware component via an OS (Operating System) or a device driver, and controls the communication device 1. The CPU 21 may be a GPU (Graphics Processing Unit). The CPU 21 includes an application 210, a protocol stack 211, and a wireless driver 212. The wireless driver 212 includes a concatenation size determination unit 213, a queue management unit 214, a list management unit 215, and a management type selection unit 216.

The on-chip memory 22 stores control programs such as the OS and device drivers executed by the CPU 21. The on-chip memory 22 includes a transmission queue 217.
The main memory 23 stores various programs and data for the application 210, the protocol stack 211, and the wireless driver 212 executed by the CPU 21, and provides a work area.

The wireless control unit 24 communicates with the other communication device via the wireless network. The wireless control unit 24 is composed of interfaces such as SDIO, PCIe, or USB for connecting to a host system composed of a CPU 21, an on-chip memory 22, and a main memory 23. SDIO is Secure Digital Input/Output, PCIe is Peripheral Component Interconnect-Express, and USB is Universal Serial Bus.

When data communication is performed in the communication device 1, the application 210 calls a socket API (Application Programming Interface).
The protocol stack 211 performs protocol processing such as TCP/IP (Transmission Control Protocol/Internet Protocol) and generates a MAC frame.

The wireless driver 212 receives MAC frames from the protocol stack 211, and performs aggregation processing on multiple MAC frames when generating a wireless communication frame. At this time, the wireless driver 212 performs aggregation processing on the MAC frames in the order they were stacked in the transmission queue 217, adds a wireless header, and transfers them to the wireless control unit 24 as a wireless communication frame. In this aggregation processing, the wireless driver 212 concatenates MAC frames for each destination so that the size is equal to or less than the aggregation size of each destination. At this time, in order to realize the A-MSDU, the wireless driver 212 concatenates the MAC frames generated by the protocol stack 211 according to the frame format of the A-MSDU.

The concatenation size determination unit 213 determines an aggregation size for each of the multiple destination nodes. For example, when the communication device 1 in FIG. 1 transmits a MAC frame to each of the communication devices 3 and 4, the destination nodes are each of the communication devices 3 and 4. The concatenation size determination unit 213 may include a table that stores the aggregation sizes set for each of the multiple destination nodes. The concatenation size determination unit 213 may determine the smallest aggregation size from the aggregation sizes for each of the multiple destination nodes, and apply the smallest aggregation size to all destinations.

The queue management unit 214 manages the transmission queue 217 into which address information accessible to the MAC frame is input. This address information is, for example, the top address of the packet management structure in which the MAC frame is stored.

The list management unit 215 manages MAC frames of the same destination in a list format by linking them based on address information accessible to the MAC frames. For example, when the first address information of a first MAC frame has been entered into the transmission queue 217, the list management unit 215 manages a second MAC frame of the same destination as the first MAC frame in a list format. At this time, the second address information of the second MAC frame that is managed in the list format is not entered into the transmission queue 217. Furthermore, the list management unit 215 manages MAC frames of the same destination by linking them at an aggregation size or less.
At this time, the MAC frames are managed by the queue management unit 214 and the list management unit 215 so that aggregation can be performed appropriately for each destination.

The management type selection unit 216 selects, based on the destination and aggregation size of the MAC frame, whether to put address information that has not been put into the transmission queue 217 into the transmission queue 217. For example, when the first address information of the first MAC frame has been put into the transmission queue 217, if a second MAC frame having the same destination as the first MAC frame can be associated with the first MAC frame at an aggregation size or less, the management type selection unit 216 selects not to put the second address information of the second MAC frame into the transmission queue 217. In this case, the list management unit 215 associates the second MAC frame with the first MAC frame and performs list management.
In addition, when the first address information of the first MAC frame has already been put into the transmission queue 217, if it is not possible to link a second MAC frame having the same destination as the first MAC frame within the aggregation size, the management type selection unit 216 selects to put the second address information of the second MAC frame into the transmission queue 217.
Furthermore, if the second address information of the second MAC frame having the same destination as the first address information of the first MAC frame has not been entered into the transmission queue 217, the management type selection unit 216 selects to enter the first address information into the transmission queue 217.

Address information that can access a MAC frame is input to the transmission queue 217. For example, the top address of a packet management structure in which the MAC frame is stored is stored in the transmission queue 217. In this case, it is assumed that there are multiple MAC frames with the same destination. In this case, the transmission queue 217 stores only the top address of the packet management structure in which one of the multiple packet management structures in which the multiple MAC frames are stored is stored.

Figure 3 is a flowchart showing the aggregation process of the wireless driver according to the embodiment. Here, the flow is explained, from when the protocol stack 211 in Figure 2 generates a MAC frame, to when the wireless driver 212 acquires it, to when the frame is managed for each destination, aggregation process is performed, and the frame is transferred to the wireless control unit 24.

Each step in FIG. 3 is realized by the CPU 21 reading and executing a program stored in the storage unit of the communication device 1. At least a part of the flowchart shown in FIG. 3 may be realized by hardware. When realized by hardware, for example, a specific compiler may be used to automatically generate a dedicated circuit on the FPGA from a program for realizing each step. Also, a gate array circuit may be formed in the same manner as the FPGA, and realized as hardware. Also, it may be realized by an ASIC.
In this case, each block in the flowchart shown in Fig. 3 can be regarded as a hardware block. Note that multiple blocks may be integrated into one hardware block, and one block may be configured as multiple hardware blocks.

In S1 of FIG. 3, the wireless driver 212 of FIG. 2 determines whether the MAC frame generated by the protocol stack 211 can be acquired, and if so, proceeds to S2, and if not, proceeds to S6.
In S2, the wireless driver 212 refers to the MAC header or IP (Internet Protocol) header in the MAC frame and determines whether or not a MAC frame with the same destination is in the transmit queue 217. At this time, the wireless driver 212 can refer to the destination MAC address or destination IP address to identify the destination.

If there is no MAC frame with the same destination in the transmit queue 217, the wireless driver 212 proceeds to S3, otherwise proceeds to S4.
In S3, the wireless driver 212 puts the top address of the packet management structure in which the MAC frame is stored into the transmit queue 217, and returns to S1.
In S4, the wireless driver 212 determines whether the total size, including the MAC frames associated with the MAC frame of the same destination, is equal to or smaller than the aggregation size determined by the concatenation size determination unit 213. If the total size exceeds the aggregation size, the wireless driver 212 proceeds to S3, and if the total size is equal to or smaller than the aggregation size, the wireless driver 212 proceeds to S5.

In S5, the wireless driver 212 associates the MAC frame to be added to the list with the MAC frame already inserted in the transmission queue 217, and performs list management. Note that the method of managing the MAC frames as a list by associating them will be described later.

In S6, the wireless driver 212 dequeues the top address of the packet management structure in which the MAC frame is stored from the transmit queue 217, and proceeds to S7.
In S7, the wireless driver 212 performs aggregation processing including the MAC frame whose top address of the storage destination packet management structure is associated with the dequeued MAC frame, and proceeds to S8.
In S8, the wireless driver 212 generates a wireless communication frame by adding a wireless header to the aggregated MAC frame, and proceeds to S9.
In S9, the wireless driver 212 transfers the wireless communication frame to the wireless control unit 24 and ends the process.

Here, in S1, a determination may be made as to whether or not the frame can be transferred to the wireless control unit 24. In other words, if the frame can be transferred to the wireless control unit 24, the first address of the packet management structure in which the MAC frame is stored may be immediately dequeued from the transmission queue 217, aggregated, and a wireless header may be added before the frame is transferred.
In addition, in S4, the determination is made based on the aggregation size, but the determination may be made based on the number of aggregations in addition to this method. For example, when the size of the MAC frame is assumed to be 1.5 Kbytes and the maximum aggregation size is 6 Kbytes, the number of aggregations may be determined to be 4.

4 is a diagram showing a packet management structure according to an embodiment of the present invention, in which a packet management structure 40 for storing MAC frames in the main memory 23 of FIG.
In FIG. 4, a packet management structure 40 includes a management information section 41 and a data section 42 .

The management information section 41 includes the size of the data section 42 , the data length of the frame stored in the data section 42 , the start address of the data section 42 , and the start address of the next packet management structure 40 .
The data section 42 is a buffer having a size capable of storing a frame, and stores a MAC header, an IP header, a TCP/UDP header, and a payload as a packet.

The MAC frame generated by the protocol stack 211 is stored in the packet management structure 40, and the wireless driver 212 obtains the MAC frame from the start address of the data section 42. In S5, the wireless driver 212 associates the MAC frame in list format using the start address of the next packet management structure 40. For the last packet management structure 40 in the list, the wireless driver 212 manages the start address of the next packet management structure 40 as NULL or 0.

The transmit queue 217 is configured as a FIFO (First In First Out) with a predetermined size, and holds the starting address of a packet management structure that stores MAC frames. The wireless driver 212 also performs list management by linking a packet management structure to the starting address of another packet management structure. List management can manage MAC frames for each destination by adding information of only the starting address, so the required memory size can be reduced compared to implementing a FIFO for MAC frames in the transmit queue 217.

Figure 5 is a diagram showing an example of transmission queue and list management according to an embodiment. Here, a case is described in which the communication device 1 in Figure 2 executes the process in Figure 3 to manage MAC frames destined for communication devices 3 and 4 so that they can be appropriately aggregated for each destination. In addition, the description is given assuming that all MAC frames are 1.5 Kbytes.

In FIG. 5, packet management structures 504-510 are generated by protocol stack 211 in numerical order, and are acquired in the order in which wireless driver 212 generated them. Packet management structures 504 and 508 store MAC frames addressed to communication device 3, and packet management structures 505-507, 509, and 510 store MAC frames addressed to communication device 4.

A method for generating a list linked to the top address stored in the transmission queue 217 in FIG. 5 will be described below.
The wireless driver 212 obtains the packet management structure 504 and puts the top address 503 of the packet management structure 504 into the transmit queue 217 .
Next, the wireless driver 212 obtains the packet management structure 505. At this time, since the destination of the packet management structure 505 is different from the destination of the packet management structure 404 already put into the transmit queue 217, the wireless driver 212 puts the top address 502 of the packet management structure 505 into the transmit queue 217.

Next, the wireless driver 212 obtains the packet management structure 506. At this time, a packet management structure 505 having the same destination as the packet management structure 506 is already present in the transmit queue 217. Therefore, the wireless driver 212 associates the start address of the packet management structure 506 with the start address 512 of the next packet management structure 40 in the management information section 41 using the start address of the packet management structure 506.

Next, the wireless driver 212 sequentially associates the packet management structures 507 and 509, which have the same destination as the packet management structure 505.
The wireless driver 212 also associates the packet management structure 504 with a packet management structure 508 that has the same destination.
The wireless driver 212 also acquires a packet management structure 510. At this time, a packet management structure 509 exists that has the same destination as the packet management structure 510, but if these are associated with each other, the maximum aggregation size of 6 Kbytes will be exceeded. In this case, the wireless driver 212 does not perform list management for linking the packet management structure 510 with the packet management structure 509, and instead puts the top address 501 of the packet management structure 510 into the transmit queue 217.

Through the above operations, a list is generated that is linked to the top address stored in the transmission queue 217 in FIG. 5 while staying within the maximum aggregation size.
Thereafter, the wireless driver 212 sequentially dequeues the MAC frames from the transmission queue 217, and aggregates the MAC frames stored in the list-managed packet management structure 40. This allows the wireless driver 212 to appropriately perform aggregation processing for each destination using only one transmission queue 217, and improves throughput during data transmission while suppressing an increase in memory resources.

Figure 6 is a diagram showing the aggregation processing sequence of a wireless driver according to an embodiment. Here, a transmission operation including aggregation processing of multiple MAC frames F1 to F7 to communication devices 3 and 4 in communication device 1 in Figure 1 will be described. It is assumed that MAC frames F1 and F5 are addressed to communication device 3, and MAC frames F2 to F4, F6, and F7 are addressed to communication device 4. It is also assumed that the storage destinations of each MAC frame are packet management structures 504 to 510 in Figure 5.

6, in S10 and S11, the protocol stack 211 in FIG. 2 generates a MAC frame F1 addressed to the communication device 3 in the main memory 23.
In S12, the wireless driver 212 acquires the MAC frame F1, and in S13, puts the head address 503 of the stored packet management structure 504 into the transmission queue 217.

In S14 and S15, the protocol stack 211 generates a MAC frame F2 addressed to the communication device 4 in the main memory 23.
In S16, the wireless driver 212 acquires the MAC frame F2, and in S17, puts the head address 502 of the packet management structure 505 to be stored into the transmission queue 217.

In S18 and S19, the protocol stack 211 generates a MAC frame F3 addressed to the communication device 4 in the main memory 23.
In S20, the wireless driver 212 acquires the MAC frame F3, and in S21 associates the start address of the packet management structure 506 to be stored with the packet management structure 505.

In S22 and S23, the protocol stack 211 generates a MAC frame F4 addressed to the communication device 4 in the main memory 23.
In S24, the wireless driver 212 acquires the MAC frame F4, and in S25 associates the top address of the packet management structure 507 to be stored with the packet management structure 506.

In S26 and S27, the protocol stack 211 generates a MAC frame F5 addressed to the communication device 3 in the main memory 23.
In S28, the wireless driver 212 acquires the MAC frame F5, and in S29 associates the top address of the packet management structure 508 to be stored with the packet management structure 504.

In S30 and S31, the protocol stack 211 generates a MAC frame F6 addressed to the communication device 4 in the main memory 23.
In S32, the wireless driver 212 acquires the MAC frame F6, and in S33 associates the top address of the packet management structure 509 to be stored with the packet management structure 507.

In S34 and S35, the protocol stack 211 generates a MAC frame F7 addressed to the communication device 4 in the main memory 23.
In S36, the wireless driver 212 acquires the MAC frame F7. At this time, when the wireless driver 212 associates the head address of the packet management structure 510 of the MAC frame F7 with the packet management structure 509, the number of frames managed in the list starting from the MAC frame F2 exceeds the aggregation size. Therefore, in S37, the wireless driver 212 puts the head address 501 of the stored packet management structure 510 into the transmission queue 217.

In S38 and S39, since the wireless driver 212 was unable to acquire the MAC frame, it dequeues the top address 503 of the packet management structure 504 from the transmit queue 217, and aggregates the MAC frames F1 and F5.
Furthermore, the wireless driver 212 dequeues the top address 502 of the packet management structure 505 from the transmit queue 217, and aggregates the MAC frames F2 to F4 and F6.
Furthermore, the wireless driver 212 dequeues the top address 501 of the packet management structure 510 from the transmit queue 217, and since there is no association with the packet management structure 510, no aggregation process is performed for the MAC frame F7.

In S40 and S41, the wireless driver 212 adds wireless headers to the aggregated MAC frame and the non-aggregated MAC frame F7 to generate wireless communication frames.
In S42, the wireless driver 212 issues a transfer command to the wireless control unit 203, and in S43 and S44, the wireless communication frame is transferred from the main memory 23 to the wireless control unit 203.

As described above, according to the above-mentioned embodiment, the queue management unit manages the transmission queue into which address information accessible to the MAC frame is input, and the list management unit manages MAC frames for the same destination based on the address information input into the transmission queue. This makes it possible to manage MAC frames for each destination while reducing the amount of data input into the transmission queue, and optimize aggregation to multiple destinations while suppressing an increase in memory resources.

In the above embodiment, the aggregation size is determined for each of the destination communication devices 3 and 4 and managed in a table, and in S4 in FIG. 3, the aggregation size for each destination is used for the judgment. In addition to this method, for example, the smallest aggregation size may be determined from the aggregation sizes of all destinations, and in S4, the judgment may be made using the smallest aggregation size for all destinations. Also, an individual aggregation size may be applied to the most frequently accessed destination, and the smallest aggregation size may be applied to the other destinations.

In the above-described embodiment, the communication devices 1 to 4 operate in infrastructure mode. Alternatively, the communication devices 1 to 4 may operate in multiple BSS (Basic Service Set) modes. The multiple BSS modes are a combination of at least two of infrastructure mode, WiFi Direct mode, and ad-hoc mode. For example, when WiFi Direct mode is used simultaneously between the communication devices 1 and 4 in addition to infrastructure mode, the communication devices 1 to 4 may generate and operate two transmission queues for each mode.

The list management unit 215 may also be configured not to perform list management for MAC frames with high urgency. High urgency MAC frames are, for example, MAC frames that include synchronization information or control information.

The present invention may provide a program that realizes one or more of the functions of the above-described embodiments to a system or device via a network or a storage medium. One or more of the functions of the above-described embodiments may also be realized by a process in which one or more processors in a computer of the system or device read and execute the program.

REFERENCE SIGNS LIST 11 communication system, 1 to 4 communication devices, 12 to 14 wireless link, 21 CPU, 22 on-chip memory, 23 main memory, 24 wireless control unit, 25 system bus, 210 application, 211 protocol stack, 212 wireless driver, 213 concatenation size determination unit, 214 queue management unit, 214 list management unit, 216 management type selection unit, 217 transmission queue

Claims (3)

1. A communication device, comprising:
a management means for managing information of a structure storing data corresponding to a MAC (Media Access Control) frame by using a first memory area;
a transmission queue having a FIFO (First In First Out) structure in a second memory area different from the first memory area;
a determination means for determining whether to process the data by a first process of inserting address information for accessing a memory address of a structure newly generated as a target for management by the management means into the tail of the transmission queue, or to process the data by a second process of managing the data in association with a structure corresponding to a MAC frame already inserted into the transmission queue without inserting address information into the transmission queue, using at least information on a destination MAC address of a MAC frame corresponding to the newly generated structure and an upper limit size of aggregation;
an input means for inputting address information for accessing a memory address of a MAC frame corresponding to the newly generated structure as a management target of the management means, to the end of the transmission queue in a transmission waiting state, when the determination means determines that the data is to be processed by a first process of inputting address information for accessing a memory address of the MAC frame corresponding to the newly generated structure as a management target of the management means, to the end of the transmission queue;
a transfer control means for transferring a wireless frame to a wireless control unit connected to a host system of the communication device via any one of an SDIO (Secure Digital Input/Output), a PCIe (Peripheral Component Interconnect-Express), or a USB (Universal Serial Bus) interface based on the address information stored in the transmission queue,
In accordance with the fact that destination MAC address information of a MAC frame corresponding to a newly generated structure does not match destination MAC address information of a MAC frame corresponding to a structure corresponding to any of the address information put into the transmission queue in a waiting state for transmission, the determination means determines that the data is to be processed by the first process of putting address information for accessing a memory address of a structure newly generated as a management target by the management means into the tail of the transmission queue, and when it is determined that destination MAC address information of a MAC frame corresponding to a newly generated structure matches destination MAC address information of a MAC frame corresponding to a structure corresponding to any of the address information put into the transmission queue in a waiting state for transmission and that a MAC frame corresponding to a structure corresponding to address information already put into the transmission queue can be linked to a MAC frame corresponding to the newly generated structure within the upper limit size, the determination means performs the transmission keying process. and when it is determined that destination MAC address information of the MAC frame corresponding to the newly generated structure matches destination MAC address information of the MAC frame corresponding to any of the address information put into the transmission queue in a waiting state for transmission but that the MAC frame indicated by the structure corresponding to the address information put into the transmission queue and the MAC frame corresponding to the newly generated structure cannot be linked within an upper limit size of the aggregation, the determination means determines that the data is to be processed by the first process of putting address information for accessing a memory address of a structure newly generated as a management target by the management means into the tail of the transmission queue,
When the determination means determines that the data is to be processed by the second process of managing the data in association with a structure corresponding to a MAC frame already put into the transmission queue without putting address information for accessing a memory address of the newly generated structure into the tail of the transmission queue, the management means performs a management process of linking a structure corresponding to the address information already put into the transmission queue, which is equal to or smaller than the upper limit size, with the newly generated structure,
when it is determined by the determination means that the first process should be performed in which address information for accessing a memory address of a structure newly generated as a target for management by the management means is added to the tail of the transmission queue, the adding means performs a process of adding the address information of the newly generated structure managed in a first memory area to the tail of the transmission queue,
the transfer control means, which has determined to transfer a wireless frame based on a MAC frame specified by address information stored in the transmission queue in a waiting state for transmission to the wireless control unit, dequeues the transmission queue of the FIFO structure to obtain address information stored at the top of the queue, references a structure in the first memory area based on the obtained address information, and, if the referenced structure is associated with one or more other structures, performs a process of aggregating the MAC frame specified by the referenced structure and the one or more MAC frames specified by the associated one or more other structures, thereby controlling the transfer of the aggregated wireless frame to the wireless control unit, while, if the referenced structure is not associated with another structure, does not perform the aggregation process and controls the transfer of a wireless frame including one MAC frame corresponding to the referenced structure that has not been aggregated to the wireless control unit;
When a plurality of pieces of address information are stored in the transmission queue in a transmission waiting state, the transfer control means, which has determined to transfer the pieces of address information to the wireless control unit, generates a plurality of wireless frames, the number of which corresponds to the number of pieces of address information stored in the transmission queue, by dequeuing the address information in order from the transmission queue having the FIFO structure, and controls the transfer of the generated plurality of wireless frames to the wireless control unit.
A communication device comprising: The communication device according to claim 1, further comprising a determination means for determining an upper limit size of an aggregation for each destination node. The communication device according to claim 1 or 2, characterized in that the aggregation process is a process of aggregating two or more MAC frames in A-MSDU (Aggregation-MAC Service Data Unit) format, and the management process is a process of linking the first address of the newly generated structure to the last structure in a structure list that is equal to or smaller than the upper limit size and corresponds to address information already entered in the transmission queue.

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