Wireless communications apparatus, and routing control and packet transmission technique in wireless network

• US 20050237973A1
• Filed: 04/14/2005
• Published: 10/27/2005
• Est. Priority Date: 04/14/2004
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Takeda, Shinji, Fujiwara, Atsushi, Yagyu, Kengo
• Granted Patent: US 7,620,010 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 45/124 using a combination of metrics
• CPC Class Codes: H04L 45/125 based on throughput or bandwidth
• CPC Class Codes: H04L 45/127 based on intermediate node capabilities
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 4/24 Accounting or billing
• CPC Class Codes: H04W 40/12 based on transmission quality or channel quality

Abstract

A wireless communications apparatus used in a wireless communications network consisting of multiple wireless communications apparatuses mutually connected via wireless links includes (a) a buffer configured to temporarily store information received from an adjacent wireless communications apparatus or a user terminal located under the wireless communications apparatus; (b) a routing control information processing unit that estimates a node cost representing traffic at the wireless communications apparatus and a link cost representing a radio condition of the link to determine a transmission route based on cost information reflecting both the node cost and the link cost; and (c) a routing control unit that designates a next hop to which information accumulated in the buffer is to be transmitted according to the determined transmission route.

Claims

1. A wireless communications apparatus used in a wireless communications network consisting of multiple wireless communications apparatuses mutually connected via wireless links, the wireless communications apparatus comprising:

a buffer configured to temporarily store information selectively received from an adjacent wireless communications apparatus and a user terminal located under the wireless communications apparatus;

a routing control information processing unit configured to estimate a node cost representing traffic at the wireless communications apparatus and a link cost representing a radio condition of the link to determine a transmission route based on cost information reflecting both the node cost and the link cost; and

a routing control unit configured to designate a next hop to which a data item accumulated in the buffer is to be transmitted according to the determined transmission route.

2. The wireless communications apparatus of claim 1, wherein the routing control information processing unit exchanges the cost information with adjacent wireless communications apparatuses in the network, and when receiving arbitrary cost information from one of the adjacent wireless communications apparatuses, the routing control information processing unit produces new cost information taking into account the node cost of the wireless communications apparatus and the link cost of a wireless link from said one of the adjacent wireless communications apparatuses, and transmits the new cost information to the adjacent wireless communications apparatuses.

3. The wireless communications apparatus of claim 1, wherein

the buffer includes a first buffer for temporarily storing information received from another wireless communication station and a second buffer for temporarily storing information received from the user terminal, and

the routing control information processing unit estimates the node cost according to the amount of data accumulated in the first buffer.

4. A routing control method for a wireless network including multiple wireless communications apparatuses mutually connected via wireless links, comprising the steps of:

determining a first total cost value at a wireless communications apparatus along a first path reaching the wireless communications apparatus, based on a node cost representing traffic of the wireless communications apparatus and a first link cost representing a radio condition of the wireless link between the wireless communications apparatus and a previous node along the first route;

comparing the first total cost with a second total cost determined for a second path reaching the wireless communications apparatus, based on the node cost and a second link cost along the second path;

selecting one of the first and second total cost values, the one having a lower cost value;

transmitting cost information representing the selected cost value to adjacent wireless communications; and

determining a transmission route for a packet so as to minimize the total cost value for reaching a destination of the packet.

5. A wireless communications apparatus used in a wireless communications network consisting of multiple wireless communications apparatuses mutually connected via wireless links, comprising:

a first buffer configured to temporarily store a first information item received from an adjacent wireless communications apparatus;

a second buffer configured to temporarily store a second information item received from a user terminal located under the wireless communications apparatus;

a priority control unit configured to schedule transmission of the first information item and the second information item according to transmission priority; and

a routing control unit configured to determine a transmission route for the first information item and/or the second information item if they are required to be transmitted to a next node, based on cost information including a node cost representing traffic at the wireless communications apparatus and a link cost representing a radio condition of the wireless link to the wireless communications apparatus.

6. The wireless communications apparatus of claim 5, wherein at least one of the first buffer and the second buffer includes a plurality of buffer segments according to types of information to be transmitted, and the priority control unit schedules the transmission of the first and second information items based on the priority of the buffer segments.

7. The wireless communications apparatus of claim 5, wherein the priority control unit schedule the transmission of the first and second information items by variably controlling the transmission ratio of the first information item stored in the first buffer to the second information item stored in the second buffer.

8. The wireless communications apparatus of claim 5, further comprising:

a monitoring unit configured to monitor the amount of information accumulated in the first buffer and if the information amount exceeds a prescribed threshold, to report occurrence of congestion to adjacent wireless communications apparatuses;

wherein

when receiving a message reporting occurrence of congestion from another wireless communications apparatus, the routing control unit designates a transmission route bypassing said other wireless communications apparatus at which the congestion has occurred.

9. The wireless communications apparatus of claim 5, further comprising:

a determination unit configured to determine a destination of the first information item, to allow the first information item to be temporarily stored in the first buffer if the first information item is to be transmitted to the adjacent wireless communications apparatus, and to allow the first information item to be delivered to the user terminal if the first information item is addressed to the user terminal.

10. A packet transmission method employed in a wireless network defined by a plurality of wireless communications apparatuses mutually connected via wireless links, comprising the steps of:

receiving a first information item at a wireless communications apparatus from an adjacent wireless communications apparatus and storing the first information item in a first buffer;

receiving a second information item at the wireless communications apparatus from a user terminal located under the wireless communications apparatus and storing the second information item in a second buffer;

scheduling transmission of the first information item and the second information item based on prescribed priority of transmission; and

determining a transmission route for the transmission of the first and second information items based on cost information reflecting a node cost representing traffic at the wireless communications apparatus and a link cost representing a radio condition of the wireless link to the wireless communications apparatus.