COMMUNICATION APPARATUS AND HANDOVER CONTROL METHOD

• US 20120264429A1
• Filed: 04/02/2012
• Published: 10/18/2012
• Est. Priority Date: 04/14/2011
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Arakawa, Taketoshi, Sakurai, Masaki, Takizawa, Eiichiro
• Granted Patent: US 8,761,845 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

It is provided a communication apparatus connected to first and second wireless networks which performs handover between the first and second wireless networks, including first and second wireless functional units which obtain connection states and wireless quality of the wireless networks. A transmitter and a receiver of the first wireless functional unit are activated, a transmitter of the second wireless functional unit is deactivated, a receiver of the second wireless functional unit is activated and the wireless quality of the first wireless network and the second wireless network are obtained when a connection between the first wireless functional unit and the first wireless network is in a connected state. The transmitter and the receiver of the first wireless functional unit are deactivated, the transmitter and the receiver of the second wireless functional unit are activated and the data suppression process is canceled after the completion of the handover.

Claims

1. A communication apparatus which is connected to a first wireless network and a second wireless network and performs handover between the first wireless network and the second wireless network, comprising:

a first wireless functional unit which connects to the first wireless network;

a second wireless functional unit which connects to the second wireless network; and

a connection unit for connecting the first wireless functional unit and the second wireless functional unit to a computer;

wherein;

the first wireless functional unit obtains a connection state and wireless quality of the first wireless network;

the second wireless functional unit obtains a connection state and wireless quality of the second wireless network;

the handover between the first wireless network and the second wireless network is controlled in accordance with instructions from the computer based on the connection states and the wireless quality obtained by the first wireless functional unit and the second wireless functional unit;

a transmitter and a receiver of the first wireless functional unit are activated, a transmitter of the second wireless functional unit is deactivated, a receiver of the second wireless functional unit is activated and the wireless quality of the first wireless network and the second wireless network are obtained in a case where a connection between the first wireless functional unit and the first wireless network is in a connected state;

the first wireless functional unit checks a communication state in a case where the wireless quality of the first wireless network is less than a predetermined threshold and the wireless quality of the second wireless network is more than the predetermined threshold;

the first wireless functional unit starts a data suppression process in a case of carrying out communication;

the first wireless functional unit checks the communication state after the start of the data suppression process;

the first wireless functional unit performs the handover after being transitioned to a standby state in a case of carrying out communication; and

the transmitter and the receiver of the first wireless functional unit are deactivated, the transmitter and the receiver of the second wireless functional unit are activated and the data suppression process is canceled after the completion of the handover.

2. The communication apparatus according to claim 1, wherein the first wireless functional unit:

checks whether the first wireless functional unit is performing a protocol process in a case where the connection between the first wireless functional unit and the first wireless network is in one of a connected state and a standby state; and

the handover is performed after a predetermined time period and the protocol process is finished when the first wireless functional unit is performing the protocol process.

3. The communication apparatus according to claim 1, wherein the first wireless functional unit performs the data suppression process by notifying congestion information.

4. The communication apparatus according to claim 1, wherein the first wireless functional unit:

performs the handover by deactivating the transmitter of the first wireless functional unit, activating the receiver of the first wireless functional unit and activating the transmitter and the receiver of the second wireless functional unit in a case where the connection between the first wireless functional unit and the first wireless network is in a standby state; and

does not perform the protocol process in a case where the connection between the first wireless functional unit and the first wireless network is in a standby state, the transmitter of the first wireless functional unit is in an inactive state and the receiver of the first wireless functional unit is in an active state.

5. The communication apparatus according to claim 1, wherein the first wireless functional unit is disconnected from the first wireless network and the transmitter and the receiver of the first wireless functional unit are deactivated in a case where the connection between the first wireless functional unit and the first wireless network is in a standby state, and the second wireless functional unit has established a connection to the second wireless network.

6. The communication apparatus according to claim 1, wherein the transmitter and the receiver of the second wireless functional unit are deactivated, the transmitter and the receiver of the first wireless functional unit are activated and the first wireless functional unit returns to a communicating state with the first wireless network in a case where the connection between the first wireless functional unit and the first wireless network is in a standby state and the second wireless functional unit has failed to establish a connection to the second wireless network.

7. The communication apparatus according to claim 1, wherein the communication apparatus controls the computer to start a timer after performing the handover and not to perform the handover before time of the timer is not up.

8. The communication apparatus according to claim 1, wherein the communication apparatus is independent of the computer in hardware and connected to the computer via a communication interface.

9. The communication apparatus according to claim 1, wherein the communication apparatus is configured integrally to the computer and connected to an internal bus of the computer.

10. A handover control method in a communication apparatus which is connected to a first wireless network and a second wireless network and performs handover between the first wireless network and the second wireless network,

the communication apparatus including a first wireless functional unit which connects with the first wireless network, a second wireless functional unit which connects with the second wireless network, and a connection unit for connecting the first wireless functional unit and the second wireless functional unit to a computer;

the method, including the steps of;

obtaining, by the first wireless functional unit, a connection state and wireless quality of the first wireless network to transmit the obtained connection state to the computer;

obtaining, by the second wireless functional unit, a connection state and wireless quality of the second wireless network to transmit the obtained connection state to the computer;

instructing, by the computer, the handover between the first wireless network and the second wireless network to the first wireless functional unit and the second wireless functional unit based on the connected states and the wireless quality obtained by the first wireless functional unit and the second wireless functional unit;

instructing, by the computer, to activate a transmitter and a receiver of the first wireless functional unit, deactivate a transmitter of the second wireless functional unit and activate a receiver of the second wireless functional unit, and causes the first wireless functional unit and the second wireless functional unit to obtain the wireless quality of the first wireless network and the second wireless network in a case where a connection between the first wireless functional unit and the first wireless network is in a connected state;

instructing, by the computer, the handover to the first wireless functional unit and the second wireless functional unit in a case where the wireless quality of the first wireless network is less than a predetermined threshold and the wireless quality of the second wireless network is more than a predetermined threshold;

checking, by the first wireless functional unit, a communication state, starting a data suppression process in a case where the first wireless functional unit is in communicating, then checking the communication state and performing the handover after being transitioned to a standby state in a case of carrying out communication; and

instructing, by the computer, to deactivate the transmitter and the receiver of the first wireless functional unit, activate the transmitter and the receiver of the second wireless functional unit and cancel the data suppression process after the completion of the handover.