RETRANSMISSION CONTROL TECHNIQUE

• US 20100017674A1
• Filed: 01/25/2007
• Published: 01/21/2010
• Est. Priority Date: 01/25/2007
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Mo, Ronghong, Luo, Ping
• Granted Patent: US 9,059,846 B2
• Time in Patent Office: Days
• US Class Current: 714/749
• CPC Class Codes: H04L 1/1816 with retransmission of the same, encoded, message
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions

Abstract

A retransmission control method, a transmitter and a receiver. The method comprises the steps of receiving, at a MIMO transmitter, a NACK signal indicating an unsuccessful decoding of a coded data packet at a MIMO receiver; receiving a reliability measure associated with one or more transmitted spatial data streams for the unsuccessfully decoded data packet; comparing the reliability measure with at least one predetermined threshold; and selecting a retransmission protocol based on the comparison of the reliability measure with the at least one predetermined threshold.

Claims

1. A retransmission control method comprising the steps of:

receiving, at a MIMO transmitter, a NACK signal indicating an unsuccessful decoding of a coded data packet at a MIMO receiver;

receiving a reliability measure associated with one or more transmitted spatial data streams for the unsuccessfully decoded data packet;

comparing the reliability measure with at least one predetermined threshold; and

selecting a retransmission protocol based on the comparison of the reliability measure with the at least one predetermined threshold.

2. The retransmission control method according to claim 1, further comprising the step of retransmitting the data packet according to the selected retransmission protocol.

3. The retransmission control method according to claim 1, wherein the retransmission protocol comprises a Chase combining protocol or an Incremental Redundancy protocol.

4. The retransmission control method according to claim 3, wherein the reliability measure comprises a system bits component and a parity bits component.

5. The retransmission control method according to claim 4, wherein the system bits component comprises system bits reliability data associated with each data stream for the unsuccessfully decoded data packet in the SCW MIMO transmission, and the parity bits component comprises parity bits reliability data of the unsuccessfully decoded data packet.

6. The retransmission control method according to claim 5, wherein the selecting of the retransmission protocol comprises:

selecting the Incremental Redundancy protocol for a retransmission data packet if the system bits reliability data is higher than a system bit threshold;

or

selecting the Chase combining protocol for the retransmission packet if the system bits reliability data is lower than or equal to the system bit threshold.

7. The retransmission control method according to claim 6, wherein the method further comprises:

selecting a lowered coding rate, as compared to an original transmission, for the retransmission data packet using the Chase combining protocol if the parity bits reliability data is lower than or equal to a parity bits threshold;

or

selecting a same coding rate, as compared to the original transmission, for the retransmission data packet using the Chase combining protocol if the parity bits reliability data is higher than the parity bits threshold.

8. The retransmission control method according to claim 6, wherein the method further comprises:

segmenting the retransmission data packet onto a plurality of spatial data streams over the same antennas as compared to the original transmission using the Chase combining protocol if the system bits reliability measure data is higher than the system bits threshold;

or

segmenting the data packet onto a plurality of data streams over different antennas as compared to the original transmission using the Chase combining protocol if the system bits reliability data is higher than the system bits threshold.

9. The retransmission control method according to claim 8, wherein the segmenting of the retransmission data packet is performed after a selecting of a lower or a same coding rate, as compared to the original transmission, for the retransmission data packet using the Chase combining protocol.

10. The retransmission control method according to claim 5, wherein the system bits component comprises system bits reliability data associated with all data streams in the MCW MIMO transmission of respective unsuccessfully decoded data packets, and the parity bits component comprises parity bits reliability data associated with said all data streams in the MCW MIMO system.

11. The retransmission control method according to claim 10, wherein the selecting of the retransmission protocol comprises:

selecting the Incremental Redundancy protocol for a retransmission data packet if the system bits reliability data is higher than a system bit threshold;

or

selecting the Chase combining protocol for the retransmission packet if the system bits reliability data is lower than or equal to the system bit threshold.

12. The retransmission control method according to claim 11, wherein the method further comprises:

selecting a lowered coding rate, as compared to an original transmission, for the retransmission data packet using the Chase combining protocol if the parity bits reliability data is lower than or equal to a parity bits threshold;

or

selecting a same coding rate, as compared to the original transmission, for the retransmission data packet using the Chase combining protocol if the parity bits reliability data is higher than the parity bits threshold.

13. The retransmission method according to claim 1, wherein the reliability measure is based on magnitudes of logarithmic likelihood ratios (LLRs) of respective demodulated system bits and parity bits of the initial unsuccessfully decoded data packet or the combination of the initial unsuccessfully decoded data packet and one or more retransmitted coded data packets.

14. The retransmission method according to claim 13, wherein the reliability measure is based on average magnitude of LLRs.

15. The retransmission method according to claim 11, wherein the reliability measure is based on a least reliable system bit and a least reliably parity bit having lowest respective magnitudes of LLR.

16. A transmitter for a MIMO communication system, the transmitter comprising:

means for receiving a NACK signal indicating an unsuccessful decoding of a coded data packet;

means for receiving a reliability measure associated with one or more transmitted spatial data streams for the unsuccessfully decoded data packet;

means for comparing the reliability measure with at least one predetermined threshold; and

means for selecting a retransmission protocol based on the comparison of the reliability measure with the at least one predetermined threshold.

17. A receiver for a MIMO communication system, the receiver comprising:

means for receiving coded data packets;

means for creating a reliability measure associated with one or more spatial data streams for an unsuccessfully decoded data packet; and

means for sending a NACK signal indicating an unsuccessful decoding of said unsuccessfully decoded data packet and the reliability measure to a transmitter associated with the sending of the coded data packets.