Communication device, communication method, and program

Abstract

To communicate without deteriorating performance of a communication module.SOLUTION: A communication device has a main system and a subsystem, and has a plurality of operation modes with different power consumption. The communication device comprises: a communication module which communicates with an external apparatus; a first bus that connects the main system and the communication module, through which the main system controls the communication module, and in which the main system controls the communication module; a second bus which connects the subsystem and the communication module, and in which the subsystem controls the communication module; a bus switching unit which switches two states of the state in which the main system and the communication module are communicably connected via the first bus, and the state in which the subsystem and the communication module are communicably connected via the second bus; and a bus switching control unit which controls switching between the two states by the bus switching unit, according to an operation mode.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a communication device, a communication method, and a program. [Background technology]

[0002] In recent years, a technology has become known for wireless LAN (Local Area Network) communications in which a normal mode in which both the main system and the subsystem are active and a power-saving mode in which only the subsystem is active are selectively executed, with the power-saving mode reducing power consumption compared to the normal mode (see, for example, Patent Document 1).In addition, a technology is also known in which, regardless of the normal mode or the power-saving mode, a data frame received from a wireless LAN module is determined to be unique to wireless communication, and the data is then processed by either the main system or the subsystem (see, for example, Patent Document 2). Summary of the Invention [Problem to be solved by the invention]

[0003] According to Patent Document 1, the wireless LAN module included in the subsystem is controlled via the wireless LAN module connection bus within the subsystem. As a result, the speed of wireless LAN communication in normal mode when the main system is activated depends on the performance of the subsystem, resulting in a problem of reduced performance of wireless LAN communication.

[0004] According to Patent Document 2, since a decision is made to distribute data frames via a subsystem with low information processing capability, packet loss occurs in wireless LAN communication, resulting in a decrease in performance of the wireless LAN communication. The problems described in Patent Documents 1 and 2 are not limited to wireless LAN communication, but can occur in communication modules in general, including other wireless and wired communications.

[0005] An embodiment of the present invention has been made in consideration of the above problems, and has as one of its objects to perform communication without degrading the performance of a communication module. [Means for solving the problem]

[0006] In order to solve the above problem, a communication device according to one embodiment of the present invention is a communication device having a main system and a subsystem, and having multiple operating modes with different power consumption, and is characterized by having a communication module that communicates with an external device, a first bus that connects the main system and the communication module and allows the main system to control the communication module, a second bus that connects the subsystem and the communication module and allows the subsystem to control the communication module, a bus switching unit that switches between two states: a state in which the main system and the communication module are communicatively connected via the first bus, and a state in which the subsystem and the communication module are communicatively connected via the second bus, and a bus switching control unit that controls the bus switching unit to switch between the two states depending on the operating mode. [Effects of the Invention]

[0007] Communication can be performed without degrading the performance of the communication module. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of a hardware configuration of a communication device 100 according to the first and second embodiments. [Figure 2] 1 is a block diagram showing an example of a functional configuration of a communication device 100 according to first and second embodiments. [Figure 3] 1 is a block diagram showing a schematic configuration of a data communication system including a bus switching control device 130 according to a first embodiment. [Figure 4] 3 is a sequence diagram illustrating operations in each operation mode of the communication device 100 according to the first embodiment. FIG. [Figure 5] 4 is a flowchart of the subsystem 120 in each operation mode of the communication device 100 according to the first embodiment. [Figure 6] 2 is a diagram showing the flow of data communication in each operation mode of the communication device 100 according to the first embodiment. FIG. [Figure 7] 10 is a flowchart showing an example of processing by the communication device 100 according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0010] <Example of communication device configuration> FIG. 1 is a block diagram showing an example of a hardware configuration of a communication device 100 according to the first and second embodiments.

[0011] The communication device 100 of this embodiment is a personal computer and an image forming device (e.g., a multifunction peripheral) equipped with functions such as a printer, scanner, copier, and fax. The communication device 100 is connected to a network 101 such as a wireless LAN. The communication device 100 may be an output device such as a PJ (Projector), an IWB (Interactive White Board: an electronic whiteboard capable of intercommunication with other devices), or a digital signage, or a HUD (Head Up Display) device. The communication device 100 may be an industrial machine, an imaging device, a sound collecting device, a medical device, a network home appliance, or an automobile (Connected Car). The communication device 100 may also be a notebook PC (Personal Computer), a mobile phone, a smartphone, a tablet terminal, a game console, a PDA (Personal Digital Assistant), a digital camera, a wearable PC, a desktop PC, or the like.

[0012] The communication device 100 includes a main system 110, a subsystem 120, a bus switching control device 130, and a wireless LAN module 140. The main system 110 and the subsystem 120 included in the communication device 100 are connected to each other via a bus A. The bus may also be called a transmission path or a communication path. In the following examples, a wireless LAN module will be used as the communication module, but the communication module may also be another wireless communication module or a wired communication module.

[0013] Communication device 100 has a plurality of operating states with different power consumption. In the following description, the operating states may be referred to as operating modes. In other words, communication device 100 has a plurality of operating modes with different power consumption.

[0014] The multiple operation modes include, for example, a normal mode and a power saving mode. In the normal mode, the main system 110 and the subsystem 120 of the communication device 100 are operating. In the normal mode, the communication device 100 executes functions provided in the communication device 100 under the control of the main system 110. On the other hand, in the power saving mode, the main system 110 of the communication device 100 is not operating, and only the subsystem 120 is operating.

[0015] The main system 110 has a higher information processing capability than the subsystem 120. On the other hand, the main system 110 also consumes more power than the subsystem 120. Therefore, in the power saving mode, the power consumption of the communication device 100 can be significantly reduced compared to the normal mode.

[0016] In the following description, the startup of the main system 110 or the subsystem 120 may be expressed as the operation of the main system 110 or the subsystem 120. In other words, the startup of the main system 110 or the subsystem 120 may be synonymous with the operation of the main system 110 or the subsystem 120.

[0017] (Main system hardware configuration) The main system 110 includes, for example, a CPU (Central Processing Unit) 111, a RAM (Random Access Memory) 112, a ROM (Read Only Memory) 113, a power control circuit 114, an internal bus 115, and a main wireless LAN module control bus 116.

[0018] The CPU 111 functions as, for example, an arithmetic processing unit and a control unit, and controls the overall operation of the main system 110 according to various programs.

[0019] The RAM 112 temporarily stores programs executed by the CPU 111, parameters that change as appropriate during the execution, and the like.

[0020] The ROM 113 stores programs, calculation parameters, etc. used by the CPU 111. The ROM 113 also stores information used in authentication processing, such as an authentication method related to wireless LAN communication, X.509 format digital certificates such as CA (Certification Authority) certificates and client certificates, and passphrases.

[0021] The power control circuit 114 controls the supply of power to the main system 110. For example, when the communication device 100 transitions to a power saving mode, the power control circuit 114 stops the supply of power to the main system 110. Furthermore, when the communication device 100 is in the power saving mode, the power control circuit 114 resumes the supply of power to the main system 110 upon receiving a return request signal from the subsystem 120 requesting a return to the normal mode. Note that power is constantly supplied to the power control circuit 114 even when the communication device 100 is in the power saving mode.

[0022] The CPU 111, RAM 112, ROM 113, and power control circuit 114 are connected via an internal bus 115, and transmit, for example, address signals, data signals, and various control signals.

[0023] A main wireless LAN module control bus 116 serving as a first bus connects the main system 110 and the bus switching control device 130. When connected to the bus switching control device 130, the main system 110 controls the wireless LAN module 140.

[0024] (Subsystem hardware configuration) The subsystem 120 includes, for example, a CPU 121, a RAM 122, a ROM 123, a signal output circuit 124, an internal bus 125, and a wireless LAN module connection bus 126.

[0025] The CPU 121 functions as, for example, an arithmetic processing unit and a control unit, and controls the overall operation of the subsystem 120 in accordance with various programs. The CPU 121 has a lower information processing capability than the CPU 111.

[0026] The RAM 122 temporarily stores programs executed by the CPU 121, parameters that change as appropriate during the execution, and the like.

[0027] The ROM 123 stores programs and calculation parameters used by the CPU 121.

[0028] The signal output circuit 124 is a circuit that outputs, under control of the CPU 121, a return request signal to the main system 110 requesting a return from the power saving mode.

[0029] The CPU 121 , RAM 122 , ROM 123 , and signal output circuit 124 are connected via an internal bus 125 .

[0030] A wireless LAN module connection bus 126 as a second bus connects the subsystem 120 and the bus switching control device 130. When connected to the bus switching control device 130, the subsystem 120 controls the wireless LAN module 140.

[0031] The bus switching control device 130 connects the main wireless LAN module control bus 116 and the wireless LAN module control bus 131, thereby connecting the main system 110 and the wireless LAN module 140 so that they can communicate with each other (a connection is established).The bus switching control device 130 also connects the wireless LAN module connection bus 126 and the wireless LAN module control bus 131, thereby connecting the subsystem 120 and the wireless LAN module 140 so that they can communicate with each other (a connection is established).

[0032] In other words, the bus switching control device 130 switches the connection destination of the wireless LAN module 140 from the main system 110 to the subsystem 120. The bus switching control device 130 also switches the connection destination of the wireless LAN module 140 from the subsystem 120 to the main system 110.

[0033] The bus switching control device 130 also communicates with the wireless LAN module 140 using a wireless LAN module control bus 131. Here, the communication speeds of the main wireless LAN module control bus 116, the wireless LAN module connection bus 126, and the wireless LAN module control bus 131 depend on the main CPU 111 or the sub-CPU 121, which is the host that controls the wireless LAN communication.

[0034] A wireless LAN module 140 serving as a communication module is connected to the main system 110 via the bus switching control device 130 and a wireless LAN module control bus 131, and further via a main wireless LAN module control bus 116 and an internal bus 115 of the main system 110. The wireless LAN module 140 is also connected to the subsystem 120 via the bus switching control device 130 and the wireless LAN module control bus 131, and further via a wireless LAN module connection bus 126 and an internal bus 125 of the subsystem 120. The wireless LAN module 140 is an interface for connecting to a network 101 such as a wireless LAN.

[0035] Here, the network 101 such as a wireless LAN may be provided by an external device different from the communication device 100. In other words, the connection of the wireless LAN module 140 to the network 101 may be synonymous with the wireless LAN module 140 communicating with an external device.

[0036] In the following description, the wireless LAN module 140 may be referred to as a communication module.

[0037] The wireless LAN module 140 may be configured as an independent component of the main system 110 and the subsystem 120, as shown in FIG. 1, or may be configured as a component included in the main system 110 or the subsystem 120.

[0038] <Functional configuration> FIG. 2 is a block diagram showing an example of a functional configuration of the communication device 100 according to the first and second embodiments.

[0039] The communication device 100 includes a main system 110 capable of executing a first authentication process and a subsystem 120 capable of executing a second authentication process. The first authentication process is an authentication process using an authentication method that requires processing related to a digital certificate. Examples of authentication methods that require processing related to a digital certificate include WPA-Enterprise authentication. The second authentication process is an authentication process using an authentication method that does not require processing related to a digital certificate. Examples of authentication methods that do not require processing related to a digital certificate include open authentication or WPA2-PSK authentication.

[0040] (Main system functional configuration) The main system 110 implements, for example, an authentication control unit 201, a processing control unit 202, a main response unit 203, a main authentication unit 204, a certificate management unit 205, a communication control unit 206, a storage unit 207, and a power saving control unit 208 by having the CPU 111 read and execute predetermined programs stored in the RAM 112 and the ROM 113. Note that at least a portion of the above functional configurations may be implemented by hardware. The predetermined programs may be stored in the ROM 123 of the subsystem 120, or may be stored in a distributed manner between the ROM 113 of the main system 110 and the ROM 123 of the subsystem 120.

[0041] The authentication control unit 201 causes the main system 110 or the subsystem 120 to execute authentication processing for joining the network 101. For example, the authentication control unit 201 causes the main authentication unit 204 or the sub-authentication unit 215 to execute processing for connecting to an access point, depending on the authentication method set in the communication device 100 and stored in the RAM 112 and the ROM 113. As an example, if the authentication method stored in the storage unit 207 is an authentication method that does not require processing related to a digital certificate, the authentication control unit 201 causes the subsystem 120 to execute authentication processing for joining the network. On the other hand, if the authentication method stored in the RAM 112 and the ROM 113 is an authentication method that requires processing related to a digital certificate, the authentication control unit 201 causes the main system 110 to execute authentication processing for joining the network 101.

[0042] The process control unit 202 causes a processing unit corresponding to a data frame received from the event processing unit 212 to execute the data frame. For example, if the received data frame is a data frame related to authentication processing, the process control unit 202 transfers the data frame to the main authentication unit 204. If the received data frame is not a data frame related to authentication processing, the process control unit 202 transfers the data frame to the main response unit 203.

[0043] Furthermore, when the process control unit 202 receives a response frame in response to the transferred data frame from the main authentication unit 204 or the main response unit 203, it transfers the response frame to the event processing unit.

[0044] The main response unit 203 creates a response frame in response to the data frame received from the process control unit 202 , and returns the created response frame to the process control unit 202 .

[0045] The main authentication unit 204 executes the first authentication process using an authentication method that requires processing related to an electronic certificate, such as WPA-Enterprise authentication. For example, the main authentication unit 204 uses the communication control unit 206 to control the wireless LAN module 140 via the bus switching control device 130, and performs processes such as connection processing to a wireless access point and encryption key update processing.

[0046] The main authentication unit 204 is an example of a first authentication unit.

[0047] For example, if the wireless LAN authentication method is WPA2-Enterprise using EAP-TLS, the main authentication unit 204 verifies the server certificate using a CA (Certification Authority) certificate read from the RAM 112, ROM 113, etc. The main authentication unit 204 also transmits the client certificate read from the RAM 112, ROM 113, etc. to perform mutual authentication and generate a pre-shared key. The main authentication unit 204 then performs a 4-way handshake using the generated pre-shared key to complete the authentication process. The 4-way handshake is a common procedure for exchanging encryption keys in wireless LAN systems, etc.

[0048] The certificate management unit 205 stores and manages electronic certificates such as the CA certificate and client certificate described above in the RAM 112 and the ROM 113. The communication control unit 206 is an interface used by the main authentication unit 204 to control the wireless LAN module 140 from the main system 110.

[0049] The storage unit 207 is realized by, for example, a program executed by the CPU 111, the RAM 112, the ROM 113, etc. The storage unit 207 stores various data (or information) in the RAM 112 and the ROM 113, such as the above-mentioned digital certificate, encryption keys such as pre-shared keys, and setting information for authentication methods.

[0050] The power saving control unit 208 is realized by, for example, a program executed by the CPU 111, the power control circuit 114, etc., and causes the communication device 100 having the main system 110 to transition to a power saving mode at a predetermined timing. The predetermined timing may be, for example, after the main system 110 or the subsystem 120 executes authentication processing to join the network 101, or when an idle state continues for a predetermined period of time or more. Alternatively, the power saving control unit 208 may be first started when the power control circuit 114 starts supplying power to the main system 110 in response to a recovery request signal transmitted from the subsystem 120, and then start up other processing units.

[0051] (Subsystem functional configuration) The subsystem 120 realizes, for example, a communication control unit 211, an event processing unit 212, a sub-response unit 213, a state control unit 214, and a sub-authentication unit 215 by the CPU 121 reading and executing predetermined programs stored in the RAM 122 and the ROM 123. Note that at least a part of the above functional configurations may be realized by hardware.

[0052] The communication control unit 211 is an interface used by the sub-authentication unit 215 to control the wireless LAN module 140 from the subsystem 120 .

[0053] When the WLAN module connection bus 126 in the subsystem 120 is used by the bus switching control device 130, the event processing unit 212 analyzes a data frame received by the WLAN module 140 and identifies a processing unit (such as the sub-response unit 213, the sub-authentication unit 215, or the process control unit 202) that will process the data frame. The event processing unit 212 then transfers the received data frame to the identified processing unit. For example, when the main system 110 is in normal mode, the event processing unit 212 transfers the received data frame to the process control unit 202 of the main system 110. Note that a data frame may also be called a packet.

[0054] Furthermore, when the communication device 100 having the main system 110 is in power saving mode, the event processing unit 212 determines whether the received data frame can be processed by the subsystem 120. Details of this determination will be described later. When the event processing unit 212 determines that the received data frame cannot be processed by the subsystem 120, the event processing unit 212 causes the communication device 100 having the main system 110 to transition to normal mode using the state control unit 214. After the event processing unit 212 has transitioned the communication device 100 having the main system 110 to normal mode, the event processing unit 212 transfers the received data frame to the processing control unit 202 of the main system 110.

[0055] On the other hand, when the main system 110 is in power saving mode and the event processing unit 212 determines that the received data frame can be processed by the subsystem 120, the event processing unit 212 transfers the received data frame to the sub-authentication unit 215 or the sub-response unit 213 depending on the type of the received data frame. For example, when the type of the received data frame is related to authentication processing such as network connection processing or encryption key update processing, the event processing unit 212 transfers the received data frame to the sub-authentication unit 215. On the other hand, when the type of the received data frame is a type other than the type related to authentication processing, the event processing unit 212 transfers the received data frame to the sub-response unit 213.

[0056] The sub-response unit 213 processes the data frame received from the event processing unit 212 within the subsystem 120 and creates response data corresponding to the received data frame. The sub-response unit 213 also creates a data frame including the created response data and returns it to the event processing unit 212. Here, the data frame processed by the sub-response unit 213 may include, for example, information that can be stored in advance in the RAM 122 and the ROM 123, such as request data inquiring about the status, device name, individual identification number, or functions of the communication device 100. For example, the RAM 122 stores the status of the communication device 100, and the ROM 123 stores the device name, individual identification number, or functions.

[0057] The state control unit 214 is realized by, for example, a program executed by the CPU 111, the signal output circuit 124, etc. The state control unit 214 returns (or transitions) the communication device 100 from the power saving mode to (or transitions to) the normal mode by transmitting a return request signal to the power saving control unit 208 of the main system 110 under control of the event processing unit 212. The state control unit 214 also transmits a signal (mode signal) indicating the current operation mode of the communication device 100 to the bus switching control device 130.

[0058] The sub-authentication unit 215 executes the second authentication process using an authentication method that can be executed within the subsystem 120. The second authentication process is, for example, an authentication method that does not require processing related to open authentication or WPA2-PSK digital certificates, and performs processing such as connection processing to a wireless LAN access point or encryption key update processing.

[0059] The sub-authentication unit 215 is an example of a second authentication unit.

[0060] <Configuration example of bus switching control device> FIG. 3 is a block diagram showing a schematic configuration of a data communication system including a bus switching control device 130 according to the first embodiment.

[0061] 3, the bus switching control device 130 in the communication device according to this embodiment includes a bus switching unit 150 and a bus switching control unit 160. The bus switching unit 150 is connected to the main system 110, the subsystem 120, and the wireless LAN module 140, and establishes a connection bus with either the main system 110 or the subsystem 120. The bus switching control unit 160 controls the connection bus of the bus switching unit 150. The bus switching unit 150 is made up of, for example, a changeover switch with a simple configuration, and can be easily provided.

[0062] The bus switching control unit 160 outputs a switching signal 170 to the bus switching unit 150 for switching the connection bus in the bus switching unit 150. The bus switching control unit 160 also outputs a reset signal 180 to the wireless LAN module 140 for resetting the wireless LAN module 140 in order to establish communication between the wireless LAN module 140 and the main system 110 or the subsystem 120 in an initial state. The bus switching control unit 160 is, for example, hardware that performs information processing such as a CPU.

[0063] The wireless LAN module 140 outputs a communication monitoring signal 190 to the bus switching control unit 160. The communication monitoring signal 190 is a signal that the bus switching control unit 160 uses to monitor communication between the main system 110 or the subsystem 120 connected to the wireless LAN module 140 (monitoring means).

[0064] The bus switching unit 150 establishes a connection between the main system 110 and the wireless LAN module 140 by connecting the main wireless LAN module control bus 116 and the wireless LAN module control bus 131. The bus switching unit 150 also establishes a connection between the subsystem 120 and the wireless LAN module 140 by connecting the wireless LAN module connection bus 126 and the wireless LAN module control bus 131.

[0065] In FIG. 3, the bus switching control unit 160 receives a communication monitoring signal 190 to detect that the connection bus to which the wireless LAN module 140 has established a connection is, for example, the main system 110, and to detect the communication status between the wireless LAN module 140 and the main system 110.

[0066] The bus switching unit 150 and the bus switching control unit 160 may be configured independent of the main system 110 and the subsystem 120 as shown in FIG. 3, or may be configured to be included in the main system 110 or the subsystem 120.

[0067] <Processing flow> Next, the processing flow of the communication method according to this embodiment will be described.

[0068] [First embodiment] FIG. 4 is a sequence diagram illustrating operations in each operation mode of the communication device 100 according to the first embodiment.

[0069] First, a description will be given of the operation of the communication device 100 when transmitting and receiving a packet data frame while the communication device 100 is operating in normal mode. In the following description, a packet data frame may be simply referred to as a data frame.

[0070] In step S101, a packet data frame received from the wireless LAN module 140 is received by the bus switching control device .

[0071] Then, in step S102, the received packet data frame is directly sent to the main system 110, and in step S103, the received packet data frame is processed by the main system 110.

[0072] Furthermore, when the communication device 100 transmits a packet data frame, the packet data frame to be transmitted is first processed by the main system 110 in step S104.

[0073] Thereafter, in step S105, the packet data frame to be transmitted is transmitted directly from the main system 110 to the bus switching control device 130.

[0074] Further thereafter, in step S106, the packet data frame is transmitted from the wireless LAN module 140 via the bus switching control device 130.

[0075] Although the above describes a case where a packet data frame is received and then another packet data frame is transmitted, the present invention is not limited to this. That is, after a packet data frame is transmitted (the processing of steps S104 to S106), another packet data frame may be received (the processing of steps S101 to S103).

[0076] Next, a description will be given of the operation of communication device 100 when communication device 100 transitions to power saving mode while operating in normal mode. In step S201, main system 110 issues an instruction (or request) to subsystem 120 to transition communication device 100 to power saving mode.

[0077] Thereafter, in step S202, the subsystem 120, in accordance with the received instruction, transmits a mode signal indicating a power saving mode to the bus switching control unit 160 in the bus switching control device 130. As a result, the bus switching control unit 160 switches the connection bus of the bus switching unit 150 from the main WLAN module control bus 116 to the WLAN module connection bus 126 (i.e., the bus for connecting to the subsystem 120). Also, in step S202, the WLAN module 140 is connected to the subsystem 120.

[0078] In step S203, the bus switching control device 130 transmits to the subsystem 120 an ACK (ACKnowledgement) in response to the mode signal received from the subsystem 120, or a signal indicating that the connection bus of the bus switching unit 150 has been switched from the main wireless LAN module control bus 116 to the wireless LAN module connection bus 126.

[0079] Also, in step S204, the subsystem 120 sends to the main system 110 an ACK in response to the instruction for the communication device 100 to transition to power saving mode, or a signal indicating that the connection bus of the bus switching unit 150 has been switched from the main wireless LAN module control bus 116 to the wireless LAN module connection bus 126.

[0080] Finally, in steps S205 and S206, the main system 110 stops the CPU 111 so that the communication device 100 transitions to the power saving mode.

[0081] The above sequence is an example and is not limiting. For example, step S201 (a step of transitioning to the power saving mode) and step S202 (a step of switching the connection bus) may be processed simultaneously or may be processed interchangeably.

[0082] Next, the operation of the communication device 100 when transmitting and receiving packet data frames while the communication device 100 is operating in the power saving mode will be described.

[0083] In step S301, a packet data frame received from the wireless LAN module 140 is received by the bus switching control device .

[0084] Then, in step S302, the received packet data frame is sent to the subsystem 120, and in step S303, the received packet data frame is processed by the subsystem 120.

[0085] Thereafter, when the communication device 100 transmits a packet data frame, the packet data frame to be transmitted is first processed by the subsystem 120 in step S304.

[0086] Thereafter, in step S305, the packet data frame to be transmitted is transmitted from the subsystem 120 to the bus switching control device 130.

[0087] Further thereafter, in step S306, the packet data frame is transmitted from the wireless LAN module 140 via the bus switching control device .

[0088] Although the above describes a case where a packet data frame is received and then another packet data frame is transmitted, the present invention is not limited to this. That is, after a packet data frame is transmitted (the processing of steps S304 to S306), another packet data frame may be received (the processing of steps S301 to S303).

[0089] Next, the operation of the communication device 100 when the communication device 100 transitions to normal mode while operating in power saving mode will be described. In step S401, a factor occurs that requires the communication device 100 to transition to normal mode. One factor may be the receipt of a packet data frame that cannot be processed by the subsystem 120 but must be processed by the main system 110.

[0090] Thereafter, in step S402, the subsystem 120 issues an instruction to the main system 110 to transition the communication device 100 to the normal mode.

[0091] In addition, in steps S403 and S404, the main system 110 starts up the CPU 111 to transition the communication device 100 to the normal mode.

[0092] Furthermore, after the communication device 100 has transitioned to the normal mode, in step S405, the main system 110 transmits an ACK or the like to the subsystem 120 in response to the instruction to transition to the normal mode.

[0093] Thereafter, in step S406, the subsystem 120 controls the bus switching control device 130 in accordance with the received instruction. Also, the bus switching control unit 160 switches the connection bus of the bus switching unit 150 to the main WLAN module control bus 116 (i.e., the bus for connecting to the main system 110).

[0094] Finally, in step S407, the communication device 100 transmits to the subsystem 120 an ACK in response to the instruction to transition to normal mode, or a signal indicating that the bus switching unit 150 has completed switching the connection bus from the wireless LAN module connection bus 126 to the main wireless LAN module control bus 116.

[0095] The above sequence is an example and is not limiting. For example, step S402 (a step of transitioning to (or returning to) the normal mode) and step S406 (a step of switching the connection bus) may be processed simultaneously or may be processed interchangeably.

[0096] FIG. 5 is a flowchart of the subsystem 120 in each operation mode of the communication device 100 according to the first embodiment.

[0097] First, a flowchart of the subsystem 120 in normal mode will be described. In step S501, in response to an instruction from the main system 110 to transition the communication device 100 to the power saving mode, the subsystem 120 determines whether or not to switch the connection destination of the wireless LAN module 140 from the main system 110 to the subsystem 120 using the bus switching unit 150.

[0098] For example, if the subsystem 120 does not receive an instruction from the main system 110 to transition the communication device 100 to the power saving mode (i.e., if the answer is No in step S501), the communication device 100 continues in the normal mode and does not switch the connection destination of the wireless LAN module 140 by the bus switching unit 150. On the other hand, if the subsystem 120 receives an instruction from the main system 110 to transition the communication device 100 to the power saving mode (i.e., if the answer is Yes in step S501), the subsystem 120 transitions the communication device 100 to the power saving mode in step S502.

[0099] In step S502, the instruction is received and the communication device 100 transitions to the power saving mode.

[0100] Thereafter, in step S503, the bus switching control device 130 switches the connection destination of the wireless LAN module 140 from the main system 110 to the subsystem 120 by the bus switching unit 150.

[0101] Through the above procedure, the communication device 100 having the subsystem 120 in the normal mode transitions from the normal mode to the power saving mode.

[0102] The above flowchart is an example, and is not limiting. For example, step S502 (transition to power saving mode) and step S503 (switching the connection destination) may be processed simultaneously or may be processed interchangeably.

[0103] Next, a description will be given of a flowchart of the subsystem 120 in the power saving mode. In step S601, the subsystem 120 receives a packet from the wireless LAN module 140. The packet may also be called packet data or a packet data frame.

[0104] Thereafter, in step S602, the subsystem 120 determines whether or not there is a factor that requires the communication device 100 to return to normal mode. In other words, the subsystem 120 determines whether or not the received packet can be processed by the subsystem 120. If the subsystem 120 determines that the processing is possible (i.e., there is no factor that requires the communication device 100 to return to normal mode), the communication device 100 returns to step S601 and processes the received packet while maintaining the power saving mode. On the other hand, if the subsystem 120 determines that the processing is not possible (i.e., there is a factor that requires the communication device 100 to return to normal mode), the subsystem 120 proceeds to step S603, which will be described later.

[0105] If the subsystem 120 determines that such a cause exists, the communication device 100 returns to the normal mode in step S603.

[0106] After the communication device 100 is returned to the normal mode, in step S604, the bus switching control device 130 switches the connection destination of the wireless LAN module from the subsystem 120 to the main system 110 by the bus switching unit 150.

[0107] Through the above procedure, the communication device 100 having the subsystem 120 in the power saving mode transitions from the power saving mode to the normal mode.

[0108] The above flowchart is an example, and the present invention is not limited to this. For example, step S603 (transition to normal mode) and step S604 (switching of connection destination) may be processed simultaneously or may be processed interchangeably.

[0109] 6A and 6B are diagrams showing the flow of data communication in each operation mode of the communication device 100 according to the first embodiment. Fig. 6A shows the flow of data communication in the normal mode, and Fig. 6B shows the flow of data communication in the power saving mode.

[0110] 6(a), in normal mode, the main system 110 controls the wireless LAN module 140 via the main wireless LAN module control bus 116 from the main system 110 via the bus switching control device 130. Also, in normal mode, the subsystem 120 stores information necessary for maintaining the wireless LAN connection even when the system transitions from normal mode to power saving mode. However, the subsystem 120 does not perform any processing related to data communication.

[0111] Here, the information required to maintain a wireless LAN connection may be, for example, authentication information related to wireless LAN communication.

[0112] As described above, according to this embodiment, in normal mode, the bus switching control device 130 enables the main system 110, which has a high information processing capability, to directly control the wireless LAN module 140. This makes it possible to achieve faster wireless LAN communication speeds than when wireless LAN communication is routed through the subsystem 120 every time communication occurs.

[0113] In addition, in FIG. 6( a ), in the normal mode, the subsystem 120 does not make any judgment on the data frame received from the wireless LAN module 140 , and the main system 110 performs the communication processing.

[0114] Thus, according to this embodiment, in normal mode, the bus switching control device 130 controls communication processing so that only the main system 110 performs it, thereby eliminating the need for the subsystem 120 to determine the data frame, and enabling communication without reducing the speed of wireless LAN communication.

[0115] The main wireless LAN module control bus 116 is an example of a first bus.

[0116] In FIG. 6( b ), in the power saving mode, the bus switching control device 130 controls the wireless LAN module 140 from the subsystem 120 via the wireless LAN module connection bus 126 .

[0117] Thus, according to this embodiment, in the power saving mode, the bus switching control device 130 enables the subsystem 120 to control the wireless LAN module 140, and therefore, in a system in which the main system 110 switches to directly control the wireless LAN module 140, it becomes possible to perform appropriate communication processing according to the power consumption mode of the communication device 100.

[0118] The wireless LAN module connection bus 126 is an example of a second bus.

[0119] [Second embodiment] 7 is a flowchart showing an example of processing of the communication device 100 according to the second embodiment. Here, among various processing executed by the communication device 100, processing related to authentication processing executed by the sub-authentication unit 215 and the main authentication unit 204 will be mainly described.

[0120] In step S701, the main system 110 and the subsystem 120 start up. At this time, the event processing unit 212 of the subsystem 120 disables the processing (connection management) by the sub-authentication unit 215. The connection management setting is stored in the RAM 122 or the ROM 123 by the event processing unit 212, for example.

[0121] In step S702, the authentication control unit 201 of the main system 110 reads out the authentication method set in the communication device 100 from the RAM 112 or the ROM 113. In step S703, the authentication control unit 201 of the main system 110 determines whether the read authentication method is an authentication method that can be processed by the sub-authentication unit 215. For example, if the authentication method set in the communication device 100 does not require processing related to a digital certificate, the authentication control unit 201 determines that the authentication method is an authentication method that can be processed by the subsystem 120. On the other hand, if the authentication method set in the communication device 100 requires processing related to a digital certificate, the authentication control unit 201 determines that the authentication method is an authentication method that cannot be processed by the subsystem 120. Examples of authentication methods that do not require processing related to a digital certificate include open authentication and WPA2-PSK authentication. Examples of authentication methods that require processing related to a digital certificate include WPA2-Enterprise authentication.

[0122] If the authentication control unit 201 determines that the processing can be performed by the subsystem 120, the authentication control unit 201 shifts the processing to step S704. On the other hand, if the authentication control unit 201 determines that the processing cannot be performed by the subsystem 120, the authentication control unit 201 shifts the processing to step S721.

[0123] When the process proceeds to step S704, the authentication control unit 201 of the main system 110 activates the sub-authentication unit 215 of the subsystem 120. At this time, the authentication control unit 201 sets the passphrase read from the RAM 112 or ROM 113 in the sub-authentication unit 215. The passphrase is used to generate a pre-shared key. The passphrase is composed of, for example, a combination of character strings and numbers. The passphrase may be, for example, a password of 10 characters or less. The passphrase is set, for example, by a user or an administrator, and stored in the RAM 112 or ROM 113.

[0124] In step S705, the sub-authentication unit 215 of the subsystem 120 starts authentication processing for joining (or connecting) to the network 101. At this time, the sub-authentication unit 215 processes a data frame for key exchange according to the authentication method, or an event specific to the wireless LAN. For example, if the authentication method is WPA2-PSK, the sub-authentication unit 215 generates a pre-shared key based on the passphrase set by the authentication control unit 201, and executes a 4-way handshake. Note that joining (or connecting) to the network 101 includes, for example, a wireless connection to an external access point.

[0125] When the authentication process by the sub-authentication unit 215 is completed in step S706, the power saving control unit 208 of the main system 110 transitions the communication device 100 having the main system 110 to a power saving mode in step S707. When the communication device 100 is transitioned to the power saving mode, the sub-system 120 executes sub-system process 1 as shown in steps S708 to S711.

[0126] In step S708, the main system 110 is turned off (that is, the communication device 100 is in power saving mode). At this time, the event processing unit 212 of the subsystem 120 enables processing by the sub-authentication unit 215 (or connection management).

[0127] In steps S709 and S710, when a predetermined event related to connection to the network 101 occurs, the event processing unit 212 starts processing the predetermined event within the range of the subsystem 120 without transitioning the communication device 100 to normal mode. For example, when the wireless LAN module 140 receives a data frame for key exchange, the event processing unit 212 transfers the received data frame to the sub-authentication unit 215. Note that the reception of a data frame for key exchange is an example of a predetermined event.

[0128] Furthermore, when the sub-authentication unit 215 receives a data frame for key exchange from the event processing unit 212, it executes an encryption key update process.

[0129] In step S711, when the processing by the sub-authentication unit 215 is completed, the event processing unit 212 returns the processing to step S709 and waits for the occurrence of a predetermined event.

[0130] Thus, according to this embodiment, if the authentication method set in the communication device 100 is a method that does not require processing related to electronic certificates, such as open authentication or WPA2-PSK authentication, the communication device 100 can process specified events, such as encryption key update processing, within the scope of the subsystem 120.

[0131] On the other hand, when the process moves from step S703 to step S721, the authentication control unit 201 of the main system 110 starts the main authentication unit 204 of the main system 110.

[0132] In step S722, the main authentication unit 204 of the main system 110 starts authentication processing for joining (or connecting to) the network 101. At this time, the main authentication unit 204 processes a data frame for key exchange according to the authentication method, or an event specific to the wireless LAN. For example, if the authentication method is WPA2-Enterprise using EAP-TLS, the main authentication unit 204 verifies the server certificate using a CA certificate read from the RAM 112 or ROM 113. The main authentication unit 204 also sends the client certificate read from the RAM 112 or ROM 113 to perform mutual authentication and generate a pre-shared key. Furthermore, the main authentication unit 204 performs a 4-way handshake using the generated pre-shared key. Note that joining (or connecting to) the network 101 includes, for example, a wireless connection to an external access point.

[0133] When the authentication process by the main authentication unit 204 is completed in step S723, the power saving control unit 208 of the main system 110 transitions the communication device 100 having the main system 110 to power saving mode in step S724. When the communication device 100 is transitioned to power saving mode, the subsystem 120 executes subsystem process 2 as shown in steps S725 to S727.

[0134] In step S725, the main system 110 is turned off (i.e., the communication device 100 is in power saving mode). At this time, the event processing unit 212 of the subsystem 120 maintains a state in which processing by the sub-authentication unit 215 (or connection management) is disabled.

[0135] In step S726, when a predetermined event related to connection to the network 101 occurs, the event processing unit 212 uses the state control unit 214 to request the main system 110 to return to the normal mode in step S727.

[0136] In step S728, the main system 110 is turned on (i.e., the communication device 100 is in normal mode). At this time, the event processing unit 212 of the subsystem 120 maintains a state in which processing by the sub-authentication unit 215 (or connection management) is disabled. Preferably, the event processing unit 212 sets processing by the sub-response unit 213 (or proxy response) to be disabled. Note that the proxy response setting is stored in the RAM 122 or ROM 123 by the event processing unit 212, for example.

[0137] In step S729, when the communication device 100 including the main system 110 returns to normal mode, the main system 110 transitions the process to step S722. For example, the event processing unit 212 of the subsystem 120 transfers the data frame for key exchange received by the wireless LAN module 140 to the main authentication unit 204 via the processing control unit 202 of the main system 110.

[0138] In this case, in step S722, the main authentication unit 204 of the main system 110 executes encryption key update processing in accordance with the key exchange data frame received from the process control unit 202.

[0139] As described above, according to this embodiment, even when the authentication method set in the communication device 100 is an authentication method that requires processing related to a digital certificate, such as WPA2-Enterprise using EAP-TLS, the communication device 100 can execute processing using the main system 110. Note that the first authentication processing that requires processing related to a digital certificate and is executed by the main system 110 is an example of a predetermined function that the communication device 100 can execute in normal mode.

[0140] As described above, according to each embodiment of the present invention, in the normal mode of the communication device 100 including the main system 110 and the subsystem 120, the bus switching control device 130 controls the communication processing to be performed only by the main system 110, thereby enabling communication without reducing the speed of wireless LAN communication.

[0141] Although the present invention has been described above based on the embodiments, the present invention is not limited to the requirements shown in the above embodiments. These requirements can be changed without departing from the spirit of the present invention, and can be appropriately determined depending on the application form.

[0142] For example, aspects of the present invention are as follows. <1> A main system and a subsystem are included, A communication device having a plurality of operation modes with different power consumption, a communication module for communicating with an external device; a first bus connecting the main system and the communication module and for the main system to control the communication module; a second bus connecting the subsystem and the communication module and for the subsystem to control the communication module; a bus switching unit that switches between two states: a state in which the main system and the communication module are communicatively connected via the first bus, and a state in which the subsystem and the communication module are communicatively connected via the second bus; a bus switching control unit that controls the bus switching unit to switch between the two states in accordance with the operation mode. <2> The plurality of operation modes with different power consumptions include a normal mode in which the main system is operating and a power saving mode in which the main system is stopped and the subsystem is operating. <1> The communication device described in <3> If the authentication method of the communication read by the main system is an authentication process that can be executed by the subsystem, the authentication process is executed by the subsystem alone; a sub-authentication unit that processes a predetermined event related to a communication connection only by the subsystem even if the predetermined event occurs after the main system has transitioned to the power saving mode after the authentication process is completed; <2> The communication device described in <4> when the operation mode transitions from the normal mode to the power saving mode, the bus switching control unit controls the bus switching unit so that the subsystem and the communication module are communicatively connected via the second bus. <2> or <3> The communication device described in <5> when the operation mode transitions from the power saving mode to the normal mode, the bus switching control unit controls the bus switching unit so that the main system and the communication module are communicatively connected via the first bus. <2> or <3> The communication device described in <6> the bus switching control unit receives a signal indicating the operation mode from the subsystem, and transmits a signal to the bus switching unit to switch between the two states in response to the signal. <1> from <5> 2. The communication device according to claim 1, <7> the communication module and the bus switching unit are configured independently of the main system and the subsystem. <1> from <6> 10. The communication device according to claim 9, <8> A communication method executed by a communication device having a main system and a subsystem and having a plurality of operation modes with different power consumption, comprising: a step of connecting the main system and a communication module that communicates with an external device via a first bus and causing the main system to control the communication module; connecting the subsystem and the communication module via a second bus and having the subsystem control the communication module; a step of switching between two states: a state in which the main system and the communication module are communicatively connected via the first bus, and a state in which the subsystem and the communication module are communicatively connected via the second bus; and controlling switching between the two states depending on the operation mode. <9> A communication device having a main system and a subsystem and having a plurality of operation modes with different power consumption, a process of connecting the main system and a communication module that communicates with an external device via a first bus and causing the main system to control the communication module; a process of connecting the subsystem and the communication module via a second bus and causing the subsystem to control the communication module; A process of switching between two states: a state in which the main system and the communication module are communicatively connected via the first bus, and a state in which the subsystem and the communication module are communicatively connected via the second bus; and a program for executing a process of controlling switching between the two states in accordance with the operation mode. [Explanation of symbols]

[0143] 100 Communication equipment 110 Main System 116 Main wireless LAN module control bus 120 Subsystems 126 Wireless LAN module connection bus 130 Bus switching control device 131 Wireless LAN module control bus 140 Wireless LAN Module 150 Bus switching unit 160 Bus switching control unit [Prior art documents] [Patent documents]

[0144] [Patent Document 1] Patent Publication No. 2023-008844 [Patent Document 2] Patent Publication No. 2017-050601

Claims

1. A main system and a subsystem are included, A communication device having a plurality of operation modes with different power consumption, a communication module for communicating with an external device; a first bus connecting the main system and the communication module, the first bus being used by the main system to control the communication module; a second bus connecting the subsystem and the communication module and for the subsystem to control the communication module; a bus switching unit that switches between two states: a state in which the main system and the communication module are communicatively connected via the first bus, and a state in which the subsystem and the communication module are communicatively connected via the second bus; a bus switching control unit that controls switching between the two states by the bus switching unit in accordance with the operation mode.

2. 2. The communication device according to claim 1, wherein the plurality of operating modes with different power consumptions include a normal mode in which the main system is operating and a power saving mode in which the main system is stopped and the subsystem is operating.

3. If the authentication method of the communication read by the main system is an authentication process that can be executed by the subsystem, the authentication process is executed by the subsystem alone; 3. The communication device according to claim 2, further comprising a sub-authentication unit that processes a predetermined event related to a communication connection only by the subsystem, even if the predetermined event occurs after the main system transitions to the power saving mode after the authentication process is completed.

4. 3. The communication device according to claim 2, wherein the bus switching control unit controls the bus switching unit so that the subsystem and the communication module are communicatively connected via the second bus when the operating mode transitions from the normal mode to the power saving mode.

5. 3. The communication device according to claim 2, wherein the bus switching control unit controls the bus switching unit so that the main system and the communication module are communicatively connected via the first bus when the operating mode transitions from the power saving mode to the normal mode.

6. 3. The communication device according to claim 1, wherein the bus switching control unit receives a signal indicating the operation mode from the subsystem, and transmits a signal to the bus switching unit to switch between the two states in response to the signal.

7. 3. The communication device according to claim 1, wherein the communication module and the bus switching unit are configured independently of the main system and the sub-system.

8. A communication method executed by a communication device having a main system and a subsystem and having a plurality of operation modes with different power consumption, comprising: a step of connecting the main system and a communication module that communicates with an external device via a first bus and causing the main system to control the communication module; connecting the subsystem and the communication module via a second bus and allowing the subsystem to control the communication module; a step of switching between two states: a state in which the main system and the communication module are communicatively connected via the first bus, and a state in which the subsystem and the communication module are communicatively connected via the second bus; and controlling switching between the two states in accordance with the operation mode.

9. A communication device having a main system and a subsystem and having a plurality of operation modes with different power consumption, a process of connecting the main system and a communication module that communicates with an external device via a first bus and causing the main system to control the communication module; a process of connecting the subsystem and the communication module via a second bus and causing the subsystem to control the communication module; a process of switching between two states: a state in which the main system and the communication module are communicatively connected via the first bus, and a state in which the subsystem and the communication module are communicatively connected via the second bus; and a program for executing a process of controlling switching between the two states in accordance with the operation mode.

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