METHOD AND APPARATUS FOR TRANSMITTING ACK/NACK INFORMATION IN AN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM BASED ON TIME DIVISION DUPLEXING

• US 20090052356A1
• Filed: 08/22/2008
• Published: 02/26/2009
• Est. Priority Date: 08/22/2007
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Dae-Gyun, Lim, Yeon-Ju, Kim, Dong-Hee, Kwon, Hwan-Joon, Jung, Jung-Soo, Yu, Jae-Chen
• Granted Patent: US 7,929,491 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04L 1/0079 Formats for control data H04L1/16 takes precedence; training sequences H04L25/00 and H04L27/00
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861

Abstract

A method is provided for transmitting control information by a Base Station (BS) in a Time Division Duplexing (TDD)-based Orthogonal Frequency Division Multiple Access (OFDMA) system. The method includes determining a TDD ratio value; when a value obtained by dividing a number of consecutive Forward-Link (FL) time slots of a predetermined time interval by a number of consecutive Reverse-Link (RL) time slots is not a positive integer, grouping Mobile Stations (MSs) into multiple groups and generating group index information; and transmitting, to the MSs, control information including the TDD ratio value and the group index information.

Claims

1. A method for transmitting control information by a Base Station (BS) in a Time Division Duplexing (TDD)-based Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:

determining a TDD ratio value;

when a value obtained by dividing a number of consecutive Forward-Link (FL) time slots of a predetermined time interval by a number of consecutive Reverse-Link (RL) time slots is not a positive integer, grouping Mobile Stations (MSs) into multiple groups and generating group index information; and

transmitting, to the MSs, control information including the TDD ratio value and the group index information.

2. The method of claim 1, wherein the TDD ratio value includes a ratio of a number of time slots allocated for each link according to an amount of data transmitted over FL and RL for the predetermined time interval.

3. The method of claim 1, further comprising:

when a value obtained by dividing the number of consecutive FL time slots of a predetermined time interval by the number of consecutive RL time slots is not a positive integer, providing MS grouping indication information to the MSs through signaling of a predetermined number of bits.

4. The method of claim 1, wherein the group index information includes information indicating to which group each MS belongs.

5. The method of claim 1, wherein the predetermined time interval includes a sum of the number of consecutive FL time slots and the number of consecutive RL time slots.

6. A method for transmitting an ACKnowledgement (ACK)/Non-ACKnowledgement (NACK) by a Mobile Station (MS) in a Time Division Duplexing (TDD)-based Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:

receiving a TDD ratio value and grouping index information from a Base Station (BS);

determining an ACK/NACK transmission ratio allocated for consecutive Reverse-Link (RL) time slots of a predetermined time interval according to the TDD ratio value and the group index information; and

transmitting ACK/NACK information for data transmitted through consecutive Forward-Link (FL) time slots of the predetermined time interval through the consecutive RL time slots according to the determined ACK/NACK transmission ratio,

wherein the consecutive RL time slots uniformly transmit ACK/NACK information allocated for the consecutive RL time slots for each group.

7. The method of claim 6, wherein the consecutive RL time slots transmit ACK/NACK information for data transmitted through the consecutive FL time slots according to an interlace index of an FL time slot corresponding to ACK/NACK information transmitted by the consecutive RL time slots.

8. The method of claim 6, wherein the TDD ratio value includes a ratio of a number of time slots allocated for each link according to an amount of data transmitted over FL and RL for the predetermined time interval.

9. The method of claim 6, wherein the group index information includes information indicating to which group each MS belongs.

10. A method for transmitting an ACKnowledgement (ACK)/Non-ACKnowledgement (NACK) by a Mobile Station (MS) in a Time Division Duplexing (TDD)-based Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:

receiving a TDD ratio value from a Base Station (BS); and

when a value obtained by dividing a number of consecutive Forward-Link (FL) time slots of a predetermined time interval by a number of consecutive Reverse-Link (RL) time slots is not a positive integer, allowing the consecutive RL time slots to uniformly transmit, to the MS, ACK/NACK information for data transmitted through FL time slots corresponding to the RL time slots.

11. The method of claim 10, further comprising:

transmitting ACK/NACK information through an interlace index of an FL time slot corresponding to ACK/NACK information transmitted by the RL time slots.

12. An apparatus for transmitting control information in a Base Station (BS) for a Time Division Duplexing (TDD)-based Orthogonal Frequency Division Multiple Access (OFDMA) system, the apparatus comprising:

a modulation unit for determining a TDD ratio value indicating a value obtained by dividing a number of consecutive Forward-Link (FL) time slots of a predetermined time interval by a number of consecutive Reverse-Link (RL) time slots, and when the value obtained by dividing the number of consecutive FL time slots of the predetermined time interval by the number of consecutive RL time slots is not a positive integer, grouping Mobile Stations (MSs) into multiple groups and generating group index information; and

a transmission unit for transmitting, to the MSs, control information including the TDD ratio value and the group index information.

13. The apparatus of claim 12, wherein the predetermined time interval includes a sum of the number of consecutive FL time slots and the number of consecutive RL time slots.

14. The apparatus of claim 12, wherein the group index information includes information indicating to which group each MS belongs.

15. An apparatus for transmitting an ACKnowledgement (ACK)/Non-ACKnowledgement (NACK) in a Mobile Station (MS) for a Time Division Duplexing (TDD)-based Orthogonal Frequency Division Multiple Access (OFDMA) system, the apparatus comprising:

a reception unit for receiving, from a Base Station (BS), grouping index information and a TDD ratio value indicating a ratio of a number of time slots allocated for each link according to an amount of data transmitted over a Forward-Link (FL) and a Reverse-Link (RL) for a predetermined time interval;

an allocation unit for determining an ACK/NACK transmission ratio allocated for consecutive RL time slots according to the TDD ratio value and the group index information, and allocating ACK/NACK information for data transmitted through the consecutive FL time slots according to the determined ACK/NACK transmission ratio; and

a transmission unit for transmitting the allocated ACK/NACK information through the consecutive RL time slots,

wherein the consecutive RL time slots uniformly transmit ACK/NACK information allocated for the consecutive RL time slots for each group.

16. The apparatus of claim 15, wherein the consecutive RL time slots transmit ACK/NACK information for data transmitted through the consecutive FL time slots according to an interlace index of an FL time slot corresponding to ACK/NACK information transmitted by the consecutive RL time slots.

17. The apparatus of claim 15, wherein the TDD ratio value includes a ratio of the number of time slots allocated for each link according to an amount of data transmitted over FL and RL for the predetermined time interval.

18. The apparatus of claim 15, wherein the group index information includes information indicating to which group each MS belongs.