Priority data transfer method

• US 20030189948A1
• Filed: 03/22/2001
• Published: 10/09/2003
• Est. Priority Date: 03/23/2000
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Sashihara, Toshiyuki
• Granted Patent: US 6,917,606 B2
• Time in Patent Office: Days
• US Class Current: 370/445
• CPC Class Codes: H04L 12/4015 by scheduling the transmission of messages at the communication node
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04W 74/0875 with assigned priorities based access

Abstract

When a send packet from a slave station and a send packet from a relay station are simultaneously sent to other relay station, the collision of the send packets against each other is detected, and the backoff time of the collided packet is calculated based on the hop count recorded in a hop count recording field of the collided packet. Therefore, the backoff time is set so that the backoff time decreases with increasing the hop count. This increases the probability of resending of the packet without collision with other packet in the resending processing, and enables the packet having a larger hop count to be preferentially sent. By virtue of this construction, a priority data transfer method can be realized which, when collision of a packet against other packet has occurred, performs resend processing based on the priority level of the packet.

Claims

1. A priority data transfer method comprising the steps of:

determining the stepwise priority level of collided packet; and

resending the collided packet based on the priority level.

13. The priority data transfer method according to any one of claims 1 to 12, wherein the communication system is a radio communication system.

2. A priority data transfer method for a communication system using random access control, said priority data transfer method comprising the steps of:

detecting collision of a send packet against other packet on a transmission line (a collision detection step);

upon the detection of the collision of the packet against other packet in the collision detection step, generating a random number (a random number generation step);

judging the priority level of the send packet (a priority level judging step);

generating a delay time, which elapses until the send packet is resent, based on the random number generated in the random number generation step and the priority level of the send packet judged in the priority level judging step (a delay time generation step); and

resending the packet after the elapse of the delay time generated in the delay time generation step.

3. The priority data transfer method according to claim 2, wherein:

a hop count recording field for recording a hop count as a measure of the priority level of the send packet is provided in the send packet; and

in judging the send packet priority level in the priority level judging step, the priority level of the send packet is judged based on the hop count recorded in the hop count recording field.

4. The priority data transfer method according to claim 3, wherein, in the delay time generation step,

the random number generated in the random number generation step is multiplied by a value obtained by subtracting a value proportional to the hop count from 1 (one) to generate the delay time, and

the packet having a larger hop count recorded in the hop count recording field is preferentially sent.

5. The priority data transfer method according to claim 2, wherein:

a priority value recording field for recording a priority value as a measure of the priority level of the send packet is provided in the send packet; and

in judging the send packet priority level in the priority level judging step, the priority level of the send packet is judged based on the priority value recorded in the priority value recording field.

6. The priority data transfer method according to claim 5, wherein, in the delay time generation step,

the random number generated in the random number generation step is multiplied by a value proportional to the priority value of the send packet to generate the delay time, and

the packet having a higher priority level recorded in the priority value recording field is preferentially sent.

7. The priority data transfer method according to claim 5 or 6, wherein the priority level of the send packet increases with decreasing the priority value.

8. The priority data transfer method according to claim 2, wherein:

the send packet has

a send data length recording field for recording the length of send data as a measure of the priority level of the send packet, and

a continued data recording field for indicating whether continued data of the send packet is present or absent, and

in judging the send packet priority level in the priority level judging step, the priority level of the send packet is judged based on the send data length and the continued data.

9. The priority data transfer method according to claim 8, wherein, in the delay time generation step,

the random number generated in the random number generation step is multiplied by a value obtained by subtracting a value proportional to the data size from 1 (one), and, when the continued data is present, in addition, the obtained value is multiplied by a predetermined value to generate a delay time, and

the packet having a larger data size recorded in the send data length recording field is preferentially sent, and

when the data size is identical, the packet, wherein continued data is present in the continued data recording field, is preferentially sent.

10. The priority data transfer method according to claim 2, wherein the send packet has

a hop count recording field for recording a hop count as a measure of the priority level of the send packet, and

a priority value recording field for recording a priority value as a measure of the priority level of the send packet, and

in judging the send packet priority level in the priority level judging step, the priority level of the send packet is judged based on the hop count and the priority value.

11. The priority data transfer method according to claim 10, wherein, in the delay time generation step,

the random number generated in the random number generation step is multiplied by a value proportional to the priority value and then by a value obtained by subtracting a value proportional to the hop count from 1 (one), whereby the delay time is generated, and

the packet having a higher priority level and the packet having a larger hop count are preferentially sent.

12. The priority data transfer method according to claim 10 or 11, wherein the priority level of the send packet increases with decreasing the priority value.