Data retransmission apparatus and method in a mobile communication system employing HARQ technique

• US 20020049068A1
• Filed: 07/05/2001
• Published: 04/25/2002
• Est. Priority Date: 07/05/2000
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Kyou-Woong, Koo, Chang-Hoi, Kwon, Hwan-Joon
• Granted Patent: US 7,236,740 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04W 52/20 using error rate

Abstract

A method and apparatus for retransmitting data in a mobile communication system wherein a receiver determines whether an initial data block received from a transmitter has an error. Upon detecting an error from the initial data block, the receiver estimates a current channel state and determines a retransmission frequency and a power level of the initial data block according to the estimated current channel state. Thereafter, the receiver transmits a retransmission request message of the initial data block together with the determined retransmission frequency and the determined power level to the transmitter. The transmitter retransmits the initial data block as many times as the retransmission frequency at the requested power level. The receiver then determines whether the retransmitted data blocks have errors, and provides the retransmitted data blocks to an upper layer upon failure to detect errors from the retransmitted data blocks. Upon failure to detect errors, the receiver measures an average power level of the initial data block and each of the retransmitted data blocks, and selectively combines only the data blocks having an average power level higher than or equal to a predetermined reference power level. The receiver discards the data blocks having an average power level lower than the reference power level.

Claims

1. A method for retransmitting data in a mobile communication system, comprising the steps of:

determining whether an initial data block received from a transmitter has an error;

estimating a current channel state and determining a retransmission frequency according to the estimated current channel state upon detecting an error in the initial data block;

transmitting a retransmission request message of the initial data block together with the determined retransmission frequency to the transmitter;

receiving data blocks retransmitted by the transmitter as many times as the retransmission frequency in response to the retransmission request message;

determining whether the retransmitted data blocks have errors; and

providing the received data blocks to an upper layer upon failure to detect errors from the received data blocks.

2. The method as claimed in claim 1, further comprising the step of measuring an average received power level of the initial data block and each of the received data blocks, and selectively combining only the data blocks having an average power level higher than or equal to a predetermined reference power level upon failure to detect errors.

3. The method as claimed in claim 2, further comprising the step of discarding the data blocks having an average power level lower than the reference power level.

4. A method for retransmitting data in a mobile communication system, comprising the steps of:

receiving a plurality of data blocks retransmitted due to an error occurring in an initial data block;

measuring an average received power level of each retransmitted data block;

comparing the average received power levels with a predetermined reference power level; and

combining the received data blocks having an average power level higher than or equal to the reference power level.

5. A method for retransmitting data in a mobile communication system, comprising the steps of:

estimating a current channel state, determining a retransmission frequency according to the estimated channel state, and transmitting a retransmission request message with the determined retransmission frequency, the version number and the sequence number upon detecting an error in a received initial data block;

receiving data blocks retransmitted as many times as the retransmission frequency in response to the retransmission request message;

measuring an average power level of each received data block;

comparing the average power levels with a predetermined reference power level; and

combining the received data blocks having an average power level higher than or equal to the reference power level.

6. A method for retransmitting data in a mobile communication system, comprising the steps of:

estimating a current channel state and transmitting a retransmission request message with retransmission frequency information to a transmitter according to the estimated channel state upon a receiver'"'"'s detecting an error in an initial data block;

retransmitting the initial data block to the receiver as many times as the retransmission frequency at the power level specified in the retransmission request message upon the transmitter'"'"'s receipt of the retransmission request message;

measuring, in the receiver, an average power level of said each received data blocks; and

selectively combining only the data blocks having an average power level higher than or equal to a predetermined reference power level, out of the retransmitted data blocks and the initial data block.

7. The method as claimed in claim 6, wherein the retransmission request message includes the retransmission frequency information, the power level information and packet ID (identification) information.

8. The method as claimed in claim 6, wherein the receiver provides the received data blocks to an upper layer, if no error is detected from the received data blocks.

9. An apparatus for retransmitting data in a mobile communication system, comprising:

a receiver for (A) estimating a current channel state, (B) transmitting a retransmission request message for the initial data block, together with retransmission frequency information according to the estimated channel state, (C) measuring an average power level of each data block received in response to the retransmission request message, and (D) combining only the data blocks having an average power level higher than or equal to a predetermined reference power level, out of the initial data block and the retransmitted data blocks; and

a transmitter for retransmitting the initial data block as many times as the retransmission frequency in response to the retransmission request message from the receiver.

10. The apparatus as claimed in claim 9, wherein the receiver discards the data blocks having an average power level lower than the reference power level.

11. The apparatus as claimed in claim 9, wherein the retransmission request message includes the retransmission frequency information and packet ID information.