Radio communication device and route search method

• US 20060293061A1
• Filed: 03/15/2005
• Published: 12/28/2006
• Est. Priority Date: 03/18/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kobayashi, Hirokazu, Kawahara, Toyoki, Kanazawa, Takeshi, Oka, Naoto
• Granted Patent: US 7,719,987 B2
• Time in Patent Office: Days
• US Class Current: 455/455
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 40/10 based on available power or energy
• CPC Class Codes: H04W 40/24 Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A radio communication device includes a reception unit for receiving a route request message from another radio communication device, a route control message processing unit for judging whether the received route request message is addressed to itself or not, a route request message management unit for deciding a delay amount for delaying response transmission or relay forwarding with regard to the route request message according to an operating state of the radio communication device when the route request message is not addressed to itself, and a delay processing unit which performs response transmission or relay forwarding to the route request message when the delay amount time has expired. Thus, a route selected giving preference to radio communication devices having a preferable operating state can be obtained.

Claims

1. A route discovery method for obtaining route information to a destination when a radio communication device connected in a network requires route information to a destination radio communication device, comprising:

a step in which a radio communication device receives a route request message broadcasted on the network, which includes a source address, a destination address, and a route request message identifier;

a step in which the radio communication device decides a delay amount for delaying processing of response transmission or relay forwarding with respect to the route request message, based on the operating state of the radio communication device, in response to the route request message, when the received route request message is not one which has already been received, and the radio communication device itself is not the destination of the required route;

a step in which the radio communication device times the delay amount and judges whether time has expired or not; and

a step in which the radio communication device performs response transmission or relay forwarding with respect to the route request message when the delay amount time has expired.

2. The route discovery method according to claim 1,

wherein the relay forwarding with respect to the route request message means that the radio communication device, when the radio communication device itself does not have route information to the destination radio communication device, broadcasts the route request message to radio communication devices located in its radio communication area, which includes the source address, the destination address and the route request message identifier of the received route request message.

3. The route discovery method according to claim 1,

wherein the response transmission with respect to the route request message means that when the radio communication device itself has route information to the destination, it transmits the route reply message, which includes the source address and the destination address of the received route request message, to the source of the received route request message.

4. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device monitors its battery remaining power, and

wherein with the battery remaining power taken to be the operating state of the radio communication device, the radio communication device sets the delay amount to be smaller when the battery remaining power is larger.

5. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device monitors its battery remaining power; and

a step in which the radio communication device calculates an estimated value of operating time from the battery remaining power, and

wherein with the estimated value of operating time taken to be the operating state of the radio communication device, the radio communication device sets the delay amount to be smaller when the estimated value of operating time is larger.

6. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device monitors its battery remaining power; and

a step in which the radio communication device calculates the number of transmittable bits with the battery remaining power, and

wherein with the transmittable number of bits taken to be the operating state of the radio communication device, the radio communication device sets the delay amount to be smaller when the transmittable number of bits is larger.

7. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device monitors its CPU usage state, and

wherein with the CPU usage state of the radio communication device taken to be its operating state, it sets the delay amount to be smaller when the CPU usage rate is smaller.

8. The route discovery method according to claim 1 further comprising:

a step in which the radio communication device identifies the flow type of the data packet when the radio communication device itself is the source transmitting a data packet or when the radio communication device forwards a data packet from another radio communication device;

a step in which the radio communication device stores the transmission data and forwarding data in predetermined storage areas divided according to the flow type;

a step in which the radio communication device identifies a flow type of data transmitted from the source of the route request message after the source of the route request message acquired route information;

a step in which the radio communication device examines the available capacity of the storage area corresponding to the flow type transmitted from the source of the route request message; and

a step in which the radio communication device decides whether the available capacityof the storage area corresponding to the flow type of data to be transmitted by the source of the route request message after acquiring route information is more than a predetermined value or not in the step in which the radio communication device decides the delay amount, and

wherein when the available capacity is more than the predetermined value, the available capacity is taken to be the operating state of the radio communication device, and the radio communication device sets the delay amount to be smaller when the available capacity is larger.

9. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device manages information of neighboring radio communication devices with which the radio communication device can directly communicate by receiving, recording and updating the information, and

wherein the total number of neighboring radio communication devices with which the radio communication device can directly communicate is taken to be its operating state, and it sets the delay amount to be smaller when the total number of neighboring radio communication devices is smaller.

10. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device manages route information to a desired destination, recording and updating the information with transmission and reception of route request messages, route reply messages, and data, and

wherein the information of the number of valid entries of routes is taken to be the operating state of the radio communication device, and the radio communication device sets the delay amount to be smaller when the number of valid entries is smaller.

11. The route discovery method according to claim 1, further comprising at least two among the following steps:

a step in which the radio communication device monitors its battery remaining power;

a step in which the radio communication device monitors its CPU usage state;

a step in which the radio communication device monitors the available capacity of the area in which the flow type of data to be transmitted from the source of the route request message after the source of the route request message has obtained route information is stored;

a step in which the radio communication device manages information of neighboring radio communication devices with which the radio communication device can directly communicate; and

a step in which the radio communication device manages route information to a desired destination and the number of valid entries of the route information, updating the information with transmission and reception of route request messages, route reply messages, and data, and

wherein in said step of deciding the delay amount, the radio communication device sets the delay amount based on a combination of at least two of the following;

the battery remaining power, the CPU using state, the available capacity, the total number of neighboring radio communication devices and information of the number of valid entries of routes.

12. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device stores an identifier in the route request message, which identifies the operating state for deciding the delay amount; and

a step in which the radio communication device discriminates the identifier which identifies the operating state for deciding the delay amount and which is stored in the received route request message, and

wherein the radio communication device decides the delay amount based on the operating state determined according to information of the operating state assigned by the identifier which identifies the operating state.

13. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device prohibits response transmission or relay forwarding in response to a received route request message when the operating state does not satisfy a specific condition; and

a step in which the radio communication device allows response transmission or relay forwarding in response to the route request message only when the radio communication device is in a better state than the specific condition.

14. The route discovery method according to claim 1, further comprising:

a step in which a user of the radio communication device performs input for setting a mode which prohibits response transmission or relay forwarding in response to a route request message, or a mode which allows them.

15. The route discovery method according to claim 1, in said step of deciding the delay amount, further comprising:

a step in which the radio communication device makes all frames in a radio link receivable when measurement of the delay amount is started;

a step in which the radio communication device switches to a mode only receiving frames addressed to itself, broadcast frames and limited broadcast frames which must be received by the device, on the radio link when the measured delay amount time has completely expired; and

a step in which the radio communication device stops the measurement of the delay amount for a processing with respect to the route request message when it detects a route reply message responding to the received route request message, and stops response transmission or relay forwarding in response to the route request message.

16. The route discovery method according to claim 1, further comprising:

a step in which the radio communication device records the route request message transmitted or relay-forwarded from neighboring radio communication devices;

a step in which during the measurement of the delay amount, the radio communication device judges whether the route request message for which the delay amount is being measured has been transmitted or relay-forwarded from all neighboring radio communication devices or not; and

a step in which the radio communication device stops the measurement of the delay amount when it judges that the route request message has been transmitted or relay-forwarded from all neighboring radio communication devices, and stops response transmission or relay forwarding in response to the route request message.

17. A radio communication device which, when route information to a destination radio communication device is required in a network in which data can be forwarded by multistage relays between plural radio communication devices, transmits a route request message to the destination in the network and receives a route reply message corresponding to the route request message and thus acquires route information, said radio communication device comprising:

a route control message processing unit judging whether the received route request message is addressed to itself or not;

a route request message management unit having a function of deciding a delay amount for delaying performance of response transmission or relay forwarding with respect to the route request message, based on the operating state of the radio communication device, when the route control message processing unit judges that the route request message is not addressed to itself; and

a delay processing unit having a function of measuring the delay amount and performing response transmission or relay forwarding with respect to the route request message when the delay amount time has expired.

18. The radio communication device according to claim 17, further comprising:

a remaining battery capacity monitor unit having a function of monitoring battery remaining power of the radio communication device, and

wherein said route request message management unit takes the battery remaining power to be the operating state of the radio communication device, and sets the delay amount to be smaller when the battery remaining power is larger, or when the estimated value of operating time calculated based on the battery remaining power is larger, or when the transmittable number of bits calculated by the battery remaining power is larger.

19. The radio communication device according to claim 17, further comprising:

a processing load monitor unit having a function of monitoring the CPU usage state of the radio communication device, and

wherein said route request message management unit takes the CPU usage state of the radio communication device to be the operating state of the radio communication device and sets the delay amount smaller when a CPU usage rate is smaller.

20. The radio communication device according to claim 17, further comprising:

a flow identification processing unit having a function when the radio communication device is the transmission source and transmits a data packet or when the radio communication device forwards a data packet from another radio communication device, of identifying the flow type of the data packet;

a buffer management unit having a function of storing transmission data and forwarding data whose flow types are specified by said flow identification processing unit in predetermined storage areas provided according to the flow type and examining available capacities of the respective storage areas, and

a route request message management unit which also has a function of judging the flow type of data transmitted from the source of the route request message based on the received route request message, and

wherein said route request message management unit takes the available capacity to be the operating state of the radio communication device when the available capacity of the storage area for the flow type of data transmitted from the source of the route request message is more than a predetermined value, and sets the delay amount to be smaller when the available capacity is larger.

21. The radio communication device according to claim 17, further comprising:

a neighborhood table management unit having a function of managing information concerning neighboring radio communication devices with which the radio communication device can directly communicate, recording and updating the information, and

wherein said route request message management unit takes the total number of neighboring radio communication devices with which the radio communication device can directly communicate to be the operating state of the radio communication device and sets the delay amount to be smaller when the total number of neighboring radio communication devices is fewer.

22. The radio communication device according to claim 17, further comprising:

a route recording unit having a function of setting validity or invalidity of route information to respective desired destinations; and

a route information recording unit having a function of recording information of the number of valid entries of routes stored in said route recording unit,

wherein said route request message management unit takes information of the number of valid entries of routes to be the operating state of the radio communication device and sets the delay amount to be smaller when the number of valid entries is smaller.

23. The radio communication device according to claim 17, further comprising at least two of the following:

a remaining battery capacity monitor unit having a function of monitoring the battery remaining power of the radio communication device;

a processing load monitor unit having a function of monitoring the CPU usage state of the radio communication device;

a buffer management unit for monitoring available capacities of areas in which are stored the flow types of the data which are to be transmitted from the source of the route request message after the source of the route request message acquires the route information;

a neighborhood table management unit having a function of managing information of neighboring radio communication devices with which the radio communication device can directly communicate; and

a route information recording unit having a function of recording information of the number of valid entries of routes, and

wherein said route request message management unit sets the delay amount by combining at least two of the following;

the battery remaining power, the CPU using state, the available capacity, the total number of neighboring radio communication devices and information of the number of valid entries of routes.

24. The radio communication device according to claim 17, further comprising:

a mode selection unit having a function of prohibiting or allowing response transmission or relay forwarding in response to the received route request message, and

wherein said mode selection unit prohibits response transmission and relay forwarding in response to the route request message when the operating state does not satisfy a specific condition, and allows response transmission or relay forwarding in response to the route request message only when the operating state is better than the specific condition.

25. The radio communication device according to claim 17, further comprising:

a mode selection unit further having a function of selecting and inputting either the prohibition or allowance of response transmission or relay forwarding in response to the received route request message; and

a display unit for displaying the operating mode which prohibits or allows response transmission or relay forwarding in response to the currently received route request message.

26. The radio communication device according to claim 17, further comprising:

a receiving mode setting unit having a function of setting a data link control unit so that all frames on a radio link can be received, and

wherein said receiving mode setting unit sets the receiving operation mode to an all-frame receivable mode when said delay processing unit starts measurement of the delay amount, instructing the stop of the measurement to said delay processing unit when said route control message processing unit detects a route reply message responding to the received route request message before the measurement of the delay amount is finished, and setting the data link control unit to be a normal frame receiving mode in which only;

a frame addressed to itself, a broadcast frame or a limited broadcast frame which must be received by the radio communication device are received from the radio link when the measured delay amount time has completely expired.

27. The radio communication device according to claim 17, further comprising:

a neighborhood relay table having a function of managing the route request messages transmitted or relay-forwarded from neighboring radio communication devices, and

wherein whether the route request message for which a delay amount is being measured has been transmitted or relay-forwarded from all neighboring radio communication devices or not during the measurement of the delay amount is judged, and said delay processing unit is instructed to stop the measurement when the radio communication device judges that the route request message has been transmitted or relay-forwarded from all neighboring radio communication devices.