Method and apparatus for data transmission

• US 20030115331A1
• Filed: 12/17/2001
• Published: 06/19/2003
• Est. Priority Date: 12/17/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Xie, Qiaobing, Stewart, Randall R., Yarroll, La Monte Henry Piggy
• Granted Patent: US 7,072,309 B2
• Time in Patent Office: Days
• US Class Current: 709/227
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters

Abstract

A method and apparatus for data transmission is provided herein. In accordance with the preferred embodiment of the present invention a loss-ratio estimator (105) estimates a current loss (L) for a communication channel (108). Once the actual loss for the channel is known, a generator (104) compares the actual loss (L) to a target loss (T). A retransmission control parameter (R) is then adjusted by the generator (104) and output to a transmitter 103 where it is used to control the retransmission behavior and to determine when to abort a bad frame. When a bad frame is aborted, transmitter 103 indicates the abortion to a receiving device (102). A receiver then utilizes the indication to stop reporting the bad frame in all subsequent ACK/NAKs.

Claims

1. A method for data transmission, the method comprising the steps of:

receiving a first bad frame a first plurality of times;

sending a first number of Acknowledgments (ACKS) or Negative Acknowledgments (NAKs) in response to the received first bad frames;

declaring the first bad frame an aborted frame;

receiving a second bad frame a second plurality of times;

sending a second number of ACKs or NAKs in response to the received second bad frames, wherein the first and the second number of ACKs or NAKs differ; and

declaring the second bad frame an aborted frame.

2. The method of claim 1 wherein the step of receiving the first bad frame comprises the step of receiving a first Radio Link Protocol (RLP) frame.

3. The method of claim 1 wherein the step of declaring the first bad frame an aborted frame comprises the step of declaring the first bad frame an aborted frame only after sending the first number ACKs or NAKs in response to the first bad frame.

4. A method for data transmission, the method comprising the steps of:

receiving an acknowledgment (ACK) or negative acknowledgment OAK);

determining a loss ratio (L) based on the received ACK/NAK;

comparing the loss ratio with a target loss ratio (T); and

adjusting a retransmission parameter (R) based on the comparison, wherein the retransmission parameter comprises a number of times a particular frame is to be retransmitted prior to aborting the frame.

5. The method claim 4 wherein the step of adjusting R comprises the steps of increasing R when L>

T, and decreasing R when L<

T and R>

0.

6. The method of claim 4 wherein the step of comparing the loss ratio with the target loss ratio comprises the step of comparing the loss ratio with a user specified loss ratio.

7. An apparatus comprising:

a loss ratio generator having an ACK or NAK as an input and outputting an estimated channel loss (L); and

a retransmission parameter generator having the estimated channel loss as an input and outputting a retransmission parameter (R) based on the estimated channel loss, wherein R comprises a number of retransmissions a frame undergoes prior to declaring the frame an aborted frame.

8. The apparatus of claim 7 wherein the retransmission parameter generator additionally has a target loss ratio (T) as an input and outputs R based additionally on T.

9. The apparatus of claim 8 wherein T is a user-specified value.

10. The apparatus of claim 7 wherein

11. The apparatus of claim 7 wherein if

L>

T then R is increased,

L<

T and R>

0 then R is decreased,

L˜

T then R is unchanged.

12. The apparatus of claim 7 further comprising a frame dropper selectively dropping frames to maintain a targeted loss ratio (T).

13. An apparatus comprising:

a receiver having a poor frame as an input;

an ACK/NAK generator coupled to the receiver, the receiver outputting an ACK/NAK based on a targeted loss ratio (T), an actual channel loss ratio (L), and a retransmission parameter (R), wherein the retransmission parameter comprises a number of times a frame is ACK/NAKed prior to declaring the frame an aborted frame.

14. The apparatus of claim 13 wherein the actual channel loss ratio is calculated by a transmitter transmitting the poor frame to the receiver.