Method and system for automatic setting of optimum number of waiting frames in automatic repeat request protocol

• US 6,081,568 A
• Filed: 04/25/1997
• Issued: 06/27/2000
• Est. Priority Date: 01/10/1996
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Oda, Toshio
• Primary Examiner(s): Ghebretinsae, Temesghen
• Assistant Examiner(s): Burd, Kevin M
• Application Number:
  US08/845,790
• Time in Patent Office: 1,159 Days
• Field of Search: 714/749, 714/750, 714/748, 370/517, 370/519, 375/358
• US Class Current: 375/358
• CPC Class Codes: H04L 1/1678 where the control information is for timing, e.g. time stamps
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/189 Transmission or retransmission of more than one copy of a message
• CPC Class Codes: H04L 7/10 Arrangements for initial synchronisation

Abstract

In a data communication system with an automatic repeat request (ARQ) protocol, a method/system capable of setting an optimum value of the RTF, which is used for threshold value of waiting time from transmitting a certain frame until retransmitting the same frame due to no acknowledgement during the waiting time, is provided. During the operation for establishing synchronization, in which a frame for control signal is transmitted repeatedly until receiving acknowledgement from the other end of apparatus, between arbitrary two apparatuses, the transmission delay is detected by using a forward count control information and backward count control information which are newly added in the forward channel information field of the frame format. The forward count control information is incremented by one for every repeated frame, and when the receiving apparatus has received one of the repeated frames, the value of the forward count control information is copied to the backward count control information in a frame to be returned. At the transmission apparatus, when the acknowledgement frame has been received, transmission delay is calculated by subtracting the value of the backward count control information in the received frame from the value of the forward count control information for a frame having been transmitted just before. This subtracted value is used as the RTF.

Claims

1. A method for automatically setting of an optimum number waiting frames (RTF) in a data communication network employing an automatic repeat request (ARQ) protocol, said method comprising the steps of:

attaching a forward count control information in a frame to be transmitted from a transmission apparatus during a synchronization establishment phase of signaling;

incrementing a value of the forward count control information by one for every frame being transmitted repeatedly during the synchronization establishment phase of signaling until receiving an acknowledgement;

copying the value of the forward count control information attached in a received frame at a reception apparatus to a backward count control information to be attached to an acknowledgement frame;

sending back the acknowledgement frame from the reception apparatus to the transmission apparatus; and

subtracting the value of the backward count control information in the received frame at the transmission apparatus from the value of the forward count control information for a frame having been transmitted just before.

2. A method as in claim 1, further comprising a step of:

using said subtracted value for a threshold value of waiting time from transmitting a certain frame until retransmitting the same frame due to no acknowledgement from the other end of the apparatus in the actual data transmission signaling phase.

3. A method as in claim 1, further comprising a step of:

incrementing the value of the backward count control information by one for every frame being transmitted repeatedly during the synchronization establishment phase of signaling until receiving a next transmission frame from the transmission apparatus.

4. A method as in claim 3, further comprising a step of:

using said subtracted value for a threshold value of waiting time from transmitting a certain frame until retransmitting the same frame due to no acknowledgement during the waiting time in the actual data transmission signaling phase.

5. A system for automatically setting an optimum number of waiting frames (RTF) in a data communication network employing an automatic repeat request (ARQ) protocol in which a synchronization establishment signaling phase and an actual data transmission signaling phase exist, said system comprising:

a first number allocating unit for allocating sequential numbers to each frame to be transmitted repeatedly from a transmission apparatus;

a second number allocating unit for copying a sequential number allocated to a frame having been received from the transmission apparatus at a reception apparatus, and allocating the copied number to a frame to be returned to the transmission apparatus from the reception apparatus as an acknowledgment frame; and

a control unit for calculating a transmission delay time between the transmission apparatus and the reception apparatus by subtracting the value of the sequential number allocated to the acknowledgment frame from the value of the sequential number allocated to a frame having been transmitted just before from the transmission apparatus, and using the transmission delay time for a threshold value of waiting time counted by a number of frames from transmitting a certain frame until retransmitting the same frame due to no acknowledgment during the waiting time in the actual data transmission signaling phase.