Radio terminal that decides a best route based on weight values of communication paths

• US 7,225,268 B2
• Filed: 11/14/2002
• Issued: 05/29/2007
• Est. Priority Date: 11/15/2001
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Watanabe, Mitsuhiro
• Primary Examiner(s): Pwu; Jeffrey C.
• Application Number:
  US10/293,365
• Publication Number:
  US 20030091001A1
• Time in Patent Office: 1,657 Days
• Field of Search: 709/224, 709/225, 709/239, 709/240, 340/539.19, 370/353, 370/390, 370/395, 370/254, 370/400
• US Class Current: 709/238
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04L 45/26 Route discovery packet
• CPC Class Codes: H04L 5/1446 of transmission speed
• CPC Class Codes: H04W 40/12 based on transmission quality or channel quality
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 40/28 for reactive routing
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A wireless terminal capable of quickly searching for the best route required for communication in a local network such as an ad hoc network is provided. Each of wireless terminals in the local network sets a bit error rates and a data transfer rate with neighboring wireless terminals and, based on the calculated values, calculates the route weight value of a link to each of the neighboring terminals. To set a route for communication between a wireless terminal and another wireless terminal, the wireless terminal issues a route search command based on the route weight value and sends the route weight value to neighboring terminals. The neighboring terminals also send the route search command sequentially to the next terminal while adding up the route weight value. A wireless terminal at the other end decides the best route from the added up route weight value and sends a response back to the starting point.

Claims

1. A wireless terminal comprising:

weight value setting means for dynamically setting a weight value of communication paths based on a communication status for each of a plurality of communication paths, each having one end connected to a neighboring other terminal, said weight value of the communication paths being a reference value for selection when communication is performed over the communication paths;

route search request relaying means, on receipt of a route search request from another terminal different from the wireless terminal of communication source, said route search request issued for establishing a communication route to a predetermined terminal as a communication destination, with the weight value of the communication paths, through which said route search request has passed, attached thereto, sending to a predetermined communication path the route search request with a weight value of the communication path attached thereto, said predetermined communication path being selected from among communication paths beginning at the wireless terminal of communication source and being connected to the wireless terminal of neighbor based on the weight values of the communication paths;

route deciding means, on receipt of the route search request specifying the wireless terminal as a communication destination, deciding a best route based on the weight value of the communication paths through which the route search request has passed, said weight value being attached to the route search request; and

route search result notifying means for notifying the route decided by said route deciding means to a source terminal of the route search request.

2. The wireless terminal as defined in claim 1 wherein the weight value attached to the route search request is an added-up value of the weight values of the communication paths beginning with the source of the route search request and wherein said route deciding means decides the best route based on a magnitude of the added-up value.

3. The wireless terminal as defined in claim 1 wherein said route deciding means decides the best route based on the weight value as well as on a time required for the route search request to be received via each route.

4. A wireless terminal comprising:

bit error rate measuring means for measuring bit error rate of each of plurality of communication paths, each having one end connected to a neighboring other terminal that is a neighbor to the wireless terminal;

transfer rate setting means for setting a data transfer rate of each of the communication paths, each having one end connected to the neighboring other terminal that is a neighbor to the wireless terminal;

weight value setting means for dynamically setting weight values based on measurement and setting contents of said bit error rate measuring means and said transfer rate setting means, said weight value being a reference value for setting a route for communication with a destination terminal over the communication paths;

route search request sending means for sending a route search request with the weight value attached thereto, to each of the communication paths, each beginning at, and being connected to, the wireless terminal, when communication is started after selecting routes via which communication is performed with a predetermined destination;

route search request relaying means, on receipt of the route search request with the weight value of communication paths, through which the route search request has passed, attached thereto, sending to a predetermined communication path the route search request with the weight value of the communication path attached thereto, said predetermined communication path beginning at the wireless terminal of communication source and being selected from among communication paths connected to the wireless terminal of neighbor based on the weight values of the communication paths;

route deciding means, on receipt of the route search request specifying the wireless terminal as a communication destination, deciding a best route based on the weight value of the communication paths through which the route search request has passed, said weight value being attached to the route search request;

route search result notifying means for notifying the route decided by said route deciding means to a source terminal of the route search request; and

communication starting means for initiating communication for the communication destination according to the indicated route, when the notification sent by said route search result notifying means is received by the source terminal of the route search request.

5. The wireless terminal as defined in claim 4 wherein the weight value attached to the route search request is an added-up value of the weight values of the communication paths beginning with the source of the route search request and wherein said route deciding means decides the best route based on a magnitude of the added-up value.

6. The wireless terminal as defined in claim 4 wherein said route deciding means decides the best route based on the weight value as well as on a time required for the route search request to be received via each route.

7. A wireless terminal comprising:

weight value setting means for setting a weight value of communication paths for each of a plurality of communication paths each having one end connected to a neighboring other terminal that is a neighbor to the wireless terminal of the communication source, said weight value of the communication paths being a reference value for selection when communication is performed over the communication paths;

route search request sending means for sending a route search request with the weight value attached thereto, to each of the communication paths, each beginning at, and being connected to, the wireless terminal of neighbor, when communication is started after selecting routes via which communication is performed with a predetermined destination;

route search request relaying means, on receipt of the route search request by the own terminal, said route search request having the weight value of the communication paths, through which the route search request has passed, attached thereto, sending to a predetermined communication path the route search request with the weight value of the communication paths attached thereto, said predetermined communication path beginning at the own terminal and being selected from among communication paths connected to the wireless terminal of neighbor based on the weight values of the communication paths;

route deciding means, on receipt of the route search request specifying the wireless terminal as a communication destination by the wireless terminal, deciding a best route based on the weight value of the communication paths through which the route search request has passed, said weight value being attached to the route search request;

route search result notifying means for notifying the route decided by said route deciding means to a source terminal of the route search request;

communication starting means for initiating communication for the communication destination according to the indicated route, when the notification sent by said route search result notifying means is received by the source terminal of the route search request;

data relaying means for sending data sent from the source terminal of the route search request after the route is decided, to a next communication path according to the route; and

communication unavailability notifying means, in case of the communication path via which said data relaying means send data being unavailable, notifying a communication initiating terminal of the communication unavailability by using rest of the routes decided by said route deciding means.

8. The wireless terminal as defined in claim 7 wherein the weight value attached to the route search request is an added-up value of the weight values of the communication paths beginning with the source of the route search request and wherein said route deciding means decides the best route based on a magnitude of the added-up value.

9. The wireless terminal as defined in claim 7 wherein the weight value attached to the route search request is an added-up value of the weight values of the communication paths beginning with the source of the route search request and wherein said route deciding means decides the best route based on a magnitude of the added-up value.

10. The wireless terminal as defined in claim 7 wherein said route deciding means decides the best route based on the weight value as well as on a time required for the route search request to be received via each route.

11. A wireless terminal comprising:

weight value setting means for setting a weight value of communication paths for each of a plurality of communication paths, each having one end connected to a neighboring other terminal, said weight value of the communication paths being a reference value for selection when communication is performed over the communication paths;

route search request relaying means, on receipt of a route search request from another terminal different from the wireless terminal of communication source, said route search request issued for establishing a communication route to a predetermined terminal as a communication destination, with the weight value of the communication paths, through which said route search request has passed, attached thereto, sending to a predetermined communication path the route search request with a weight value of the communication path attached thereto, said predetermined communication path being selected from among communication paths beginning at the wireless terminal of communication source and being connected to the wireless terminal of neighbor based on the weight values of the communication paths;

route deciding means, on receipt of the route search request specifying the wireless terminal as a communication destination, deciding a best route based on the weight value of the communication paths through which the route search request has passed, said weight value being attached to the route search request; and

route search result notifying means for notifying the route decided by said route deciding means to a source terminal of the route search request.

wherein said route search request relaying means selects the communication path not using an already-selected communication path by referencing the route sent with the route search request and relays the route search request.

12. A wireless terminal comprising:

bit error rate measuring means for measuring bit error rate of each of plurality of communication paths, each having one end connected to a neighboring other terminal that is a neighbor to the wireless terminal;

transfer rate setting means for setting a data transfer rate of each of the communication paths, each having one end connected to the neighboring other terminal that is a neighbor to the wireless terminal;

weight value setting means for setting weight values based on measurement and setting contents of said bit error rate measuring means and said transfer rate setting means, said weight value being a reference value for setting a route for communication with a destination terminal over the communication paths;

route search request sending means for sending a route search request with the weight value attached thereto, to each of the communication paths, each beginning at, and being connected to, the wireless terminal, when communication is started after selecting routes via which communication is performed with a predetermined destination;

route search request relaying means, on receipt of the route search request with the weight value of communication paths, through which the route search request has passed, attached thereto, sending to a predetermined communication path the route search request with the weight value of the communication path attached thereto, said predetermined communication path beginning at the wireless terminal of communication source and being selected from among communication paths connected to the wireless terminal of neighbor based on the weight values of the communication paths;

route deciding means, on receipt of the route search request specifying the wireless terminal as a communication destination, deciding a best route based on the weight value of the communication paths through which the route search request has passed, said weight value being attached to the route search request;

route search result notifying means for notifying the route decided by said route deciding means to a source terminal of the route search request; and

communication starting means for initiating communication for the communication destination according to the indicated route, when the notification sent by said route search result notifying means is received by the source terminal of the route search request,

wherein the weight value attached to the route search request is an added-up value of the weight values of the communication paths beginning with the source of the route search request and wherein said route deciding means decides the best route based on a magnitude of the added-up value.