Apparatus and method for Orthogonal Spatial Multiplexing in a closed-loop MIMO-OFDM system

• US 20070189416A1
• Filed: 01/19/2007
• Published: 08/16/2007
• Est. Priority Date: 01/19/2006
• Status: Abandoned Application

• Current Assignee: Korea University Industrial & Academic Collaboration Foundation, Samsung Electronics Co. Ltd.
• Original Assignee: Korea University Industrial & Academic Collaboration Foundation, Samsung Electronics Co. Ltd.
• Inventors: Jang, Kyung-Hun, Lee, Dong-Jun, Hwang, Hyo-Sun, Kim, Young-Soo, Lee, In-Kyu, SUH, Jung-Hoon, Lee, Heun-Chul
• Application Number:
  US11/655,780
• Publication Number:
  US 20070189416A1
• Time in Patent Office: Days
• US Class Current: 375/299
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

An Orthogonal Spatial Multiplexing (OSM) apparatus and method in a closed-loop Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system are provided. In the OSM method, a basic signal model is set and transmission symbols are encoded. A real-valued system model corresponding to the basic signal model is obtained. To achieve orthogonality, rotations angles are calculated and are applied to the encoded transmission symbols.

Claims

1. A method of transmission in a transmitter in a closed loop multiple input multiple output communication system, the method comprising the steps of:

precoding transmission symbols using a rotation angle from a receiver; and

transmitting the precoded transmission symbols over a plurality of antennas.

2. The method of claim 1, wherein the precoding step comprises encoding the transmission symbols using

$[\begin{array}{cc}1& 0\\ 1& \exp \end{array}$

( θ

k ) ] .

3. The method of claim 2, wherein the rotation angle is calculated in the receiver using

${\theta }_{}$

k = tan - 1 ⁡

( B k A k ) ±

π

2 $\mathrm{where}$ $A_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{\mathrm{ml},k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\sin <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{\mathrm{ml},k}\right),<br><br>B_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{\mathrm{ml},k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\cos <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{\mathrm{ml},k}\right).$

4. The method of claim 1, wherein the communication system is an OFDM (Orthogonal Frequency Division Multiplexing) system.

5. A method of receipt in a receiver in a closed loop multiple input multiple output communication system, the method comprising the steps of:

receiving transmission symbols precoded in a transmitter using a rotation angle from the receiver over a plurality of antennas; and

linear decoding transmission symbols.

6. The method of claim 5, wherein the transmission symbols are precoded in the transmitter using

$[\begin{array}{cc}1& 0\\ 1& \exp \end{array}$

( θ

k ) ] .

7. The method of claim 6, wherein the rotation angle is calculated in the receiver using

${\theta }_{}$

k = tan - 1 ⁡

( B k A k ) ±

π

2 $\mathrm{where}$ $A_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\sin <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}\right),<br><br>B_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\cos <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}\right).\mathrm{fghv}$

8. The method of claim 5, wherein the communication system is an OFDM (Orthogonal Frequency Division Multiplexing) system.

9. A transmitter in a closed loop multiple input multiple output communication system, the transmitter comprising:

a precoder for precoding transmission symbols using a rotation angle from a receiver; and

a plurality of antennas over which the precoded transmission symbols are transmitted.

10. The transmitter of claim 9, wherein the precoder encodes the transmission symbols using

$[\begin{array}{cc}1& 0\\ 1& \exp \end{array}$

( θ

k ) ] .

11. The transmitter of claim 10 wherein the rotation angle is calculated in the receiver using

${\theta }_{}$

k = tan - 1 ⁡

( B k A k ) ±

π

2 $\mathrm{where}$ $A_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\sin <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}\right),<br><br>B_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\cos <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}\right).$

12. The transmitter of claim 9, wherein the communication system is an OFDM (Orthogonal Frequency Division Multiplexing) system.

13. A receiver in a closed loop multiple input multiple output communication system, the receiver comprising:

a plurality of antennas over which transmission symbols precoded in a transmitter using a rotation angle from the receiver are received; and

a decoder for linear decoding transmission symbols.

14. The receiver of claim 13, wherein the transmission symbols are precoded in the transmitter using

$[\begin{array}{cc}1& 0\\ 1& \exp \end{array}$

( θ

k ) ] .

15. The receiver of claim 14, wherein the rotation angle is calculated in the receiver using

${\theta }_{}$

k = tan - 1 ⁡

( B k A k ) ±

π

2 $\mathrm{where}$ $A_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\sin <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}\right),<br><br>B_k=\underset{m=1}{\overset{M}{\sum <br><br>}}<br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}<br><br><br><br><br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}<br><br><br><br>\cos <br><br>\left(\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>2,k}-\mathrm{\angle <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\stackrel{\_}{h}}_{m<br><br>\text{\hspace{1em}<br><br>}<br><br>1,k}\right).$

16. The receiver of claim 13, wherein the communication system is an OFDM (Orthogonal Frequency Division Multiplexing) system.