Method and apparatus for ordering retransmissions in an NxM MIMO system

• US 20070115864A1
• Filed: 08/11/2006
• Published: 05/24/2007
• Est. Priority Date: 08/12/2005
• Status: Active Grant

• Current Assignee: New Jersey Institute of Technology, Samsung Electronics Co. Ltd.
• Original Assignee: New Jersey Institute of Technology, Samsung Electronics Co. Ltd.
• Inventors: Kim, Dong-Ho, Lee, Ye-Hoon, Bar-Ness, Yeheskel, Malagarriga, Guillem
• Granted Patent: US 8,064,428 B2
• Time in Patent Office: Days
• US Class Current: 370/278
• CPC Class Codes: H04B 7/0623 Auxiliary parameters, e.g. power control [PCB] or not acknowledged commands [NACK], used as feedback information
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0625 Transmitter arrangements
• CPC Class Codes: H04L 1/0668 Orthogonal systems, e.g. using Alamouti codes
• 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 1/1819 with retransmission of additional or different redundancy
• 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

Abstract

A method is provided for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×M antennas. A transmitter splits a coded data stream into N sub-packets, and transmits the N sub-packets to a receiver via N transmission antennas. The receiver removes interferences of the N sub-packets received via M reception antennas, and independently decodes the interference-removed sub-packets. The receiver transmits an acknowledgement (ACK) or a negative acknowledgement (NACK) to the transmitter based on errors included in the decoded sub-packets. Upon receipt of the NACK, the transmitter retransmits to the receiver a sub-packet retransmission using ordering based on an Alamouti space-time coding scheme.

Claims

1. A method for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×

M antennas, the method comprising the steps of;

splitting, at a transmitter, a coded data stream into N sub-packets, and transmitting the N sub-packets to a receiver via N transmission antennas;

removing, at the receiver, interferences of the N sub-packets received via M reception antennas, and independently decoding the interference-removed sub-packets;

transmitting, at the receiver to the transmitter, an acknowledgement (ACK) or a negative acknowledgement (NACK) depending on errors included in the decoded sub-packets; and

upon receipt of the NACK, retransmitting to the receiver, at the transmitter, a sub-packet retransmission using ordering based on an Alamouti space-time coding scheme.

2. The method of claim 1, further comprising canceling interference and decoding by combining, at the receiver, the retransmitted sub-packet with the previous defective sub-packet on a symbol level.

3. The method of claim 1, wherein the interference removing is achieved by Minimum Mean Square Examination (MMSE) or Zero Forcing (ZF).

4. The method of claim 1, wherein an N×

M channel gain obtained by the Alamouti space-time coding scheme for the retransmission ordering depends on a signal-to-noise ratio (SNR) criterion of each reception antenna, determined at the receiver at every retransmission.

5. The method of claim 4, wherein a highest SNR of each reception antenna maximizes a determinant that derives a channel matrix after each retransmission.

6. The method of claim 5, wherein the channel matrix is adaptively changed by checking a channel every time there is a need for retransmission.

7. The method of claim 5, wherein the channel matrix is expressed as

$H_{M\times }$

N = ( h 11 h 12 ⋯

h 1 ⁢

N h 21 h 22  

⋮

⋮

 

⋰

⋮

h M ⁢

 

⁢

1 …

…

h M ⁢

 

⁢

N ) .

8. A transmission apparatus for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×

M antennas, the apparatus comprising;

a channel encoder for encoding input information bits based on a coding scheme, and generating coded packets having a specific length;

a spatial demultiplexer for encoding the coded packets based on a space-time coding scheme, and parallel-converting the packets into N sub-blocks;

symbol mappers for modulating the sub-blocks into modulation symbol streams using a modulation scheme, mapping the symbol streams to times and frequencies based on a pilot sub-carrier position set pattern, and outputting the mapping results to associated transmission antennas; and

N transmission antennas for separately transmitting N sub-packets split from each of the coded symbol streams,

wherein upon receipt of a negative acknowledgement (NACK) due to transmitted packet errors, the apparatus retransmits to a receiver a packet retransmission using ordering based on an Alamouti space-time coding scheme.

9. The transmission apparatus of claim 8, wherein an N×

M channel gain obtained by the Alamouti space-time coding scheme for the retransmission ordering depends on a signal-to-noise ratio (SNR) criterion of each reception antenna, determined at the receiver at every retransmission.

10. The transmission apparatus of claim 9, wherein a highest SNR of each reception antenna maximizes a determinant that derives a channel matrix after each retransmission.

12. The transmission apparatus of claim 10, wherein the channel matrix is expressed as

$H_{M\times }$

N = ( h 11 h 12 ⋯

h 1 ⁢

N h 21 h 22  

⋮

⋮

 

⋰

⋮

h M ⁢

 

⁢

1 …

…

h M ⁢

 

⁢

N ) .

11. The transmission apparatus of claim 11, wherein the channel matrix is adaptively changed by checking a channel every time there is a need for retransmission.

13. A reception apparatus for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×

M antennas, the apparatus comprising;

M reception antennas for separately receiving N sub-packets split from a coded symbol stream;

a pre-combiner for combining a packet retransmitted according to retransmission ordering with a previous defective packet on a symbol level; and

a detector for removing interference of a signal received from the pre-combiner, splitting the interference-removed signal into N transmission data sub-packets, and outputting independently decoded sub-packet signals;

wherein the apparatus transmits an acknowledgement (ACK) or a negative acknowledgement (NACK) to a transmitter depending on errors included in the decoded sub-packet.

14. The reception apparatus of claim 13, wherein the interference removing is achieved by Minimum Mean Square Examination (MMSE) or Zero Forcing (ZF).

15. The reception apparatus of claim 13, wherein an N×

M channel gain obtained by the Alamouti space-time coding scheme for the retransmission ordering depends on a signal-to-noise ratio (SNR) criterion of each reception antenna, determined at the receiver at every retransmission.

16. The reception apparatus of claim 15, wherein a highest SNR of each reception antenna maximizes a determinant that derives a channel matrix after each retransmission.

17. The reception apparatus of claim 16, wherein the channel matrix is adaptively changed by checking a channel every time there is a need for retransmission.

18. The reception apparatus of claim 16, wherein the channel matrix is expressed as

$H_{\mathrm{MxN}}=(\begin{array}{ccc}{h}_{11}& h_{12}& \cdots \end{array}$

h 1 ⁢

N h 21 h 22  

⋮

⋮

 

⋰

⋮

h M ⁢

 

⁢

1 ⋯

⋯

h MN ) .