Method and apparatus for transmitting ACK/NACK information in an orthogonal frequency division multiple access system based on time division duplexing

• US 7,929,491 B2
• Filed: 08/22/2008
• Issued: 04/19/2011
• 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: Yu, Jae-Chen, Kim, Dae-Gyun, Lim, Yeon-Ju, Kim, Dong-Hee, Kwon, Hwan-Joon, Jung, Jung-Soo
• Primary Examiner(s): Yao; Kwang B
• Assistant Examiner(s): Bokhari; Syed M
• Application Number:
  US12/196,945
• Publication Number:
  US 20090052356A1
• Time in Patent Office: 970 Days
• Field of Search: 370/329, 370/332, 370/280, 370/343, 455/445, 455/452
• US Class Current: 370/328
• 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 of a number of time slots allocated for Forward-Link (FL) and a number of time slots allocated for Reverse-Link (RL); if the TDD ratio value is not an 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 value obtained by dividing a number of time slots allocated for a Forward-Link (FL) by a number of time slots allocated for a Reverse-Link (RL);

if the value is not a positive integer but is a fraction, grouping Mobile Stations (MSs) into multiple groups and generating group index information; and

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

2. The method of claim 1, further comprising:

if the value is not a positive integer but is a fraction, providing the group index information to the MSs through signaling of a predetermined number of bits.

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

4. 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 value obtained by dividing a number of time slots allocated for a Forward-Link (FL) by a number of time slots allocated for a Reverse-Link (RL) and group 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 value and the group index information; and

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

5. The method of claim 4, wherein the consecutive RL time slots transmit the ACK/NACK information for data transmitted through the consecutive FL time slots is transmitted according to an interlace index of an FL time slot corresponding to ACK/NACK information transmitted by the consecutive RL time slots.

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

7. 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 value obtained by dividing a number of time slots allocated for a Forward-Link (FL) by a number of time slots allocated for a Reverse-Link (RL) from a Base Station (BS); and

if the value is not a positive integer but is a fraction, allowing the consecutive RL time slots to uniformly transmit, to the BS, ACK/NACK information for data transmitted through FL time slots corresponding to the RL time slots.

8. The method of claim 7, 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.

9. 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 value obtained by dividing a number of time slots allocated for a Forward-Link (FL) by a number of time slots allocated for a Reverse-Link (RL), and if the value is not a positive integer but is a fraction, 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 value and the group index information.

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

11. 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), group index information and a value obtained by dividing a number of time slots allocated for a Forward-Link (FL) by a number of time slots allocated for a Reverse-Link (RL);

an allocation unit for determining an ACK/NACK transmission ratio allocated for consecutive RL time slots according to the 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.

12. The apparatus of claim 11, 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.

13. The apparatus of claim 11, wherein the group index information includes information indicating to which group each MS belongs.