Method and apparatus for transmitting signals in a multi-hop wireless communication system

• US 20090252243A1
• Filed: 04/02/2009
• Published: 10/08/2009
• Est. Priority Date: 04/02/2008
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Original Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Inventors: Lee, Sang-Min, Choi, Sang Won, Chung, Sae-Young, Cho, Myeon-Kyun, Yu, Tak-Ki, Kim, Eun-Yong
• Granted Patent: US 8,345,787 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo

Abstract

A method and apparatus for transmitting signals in a multi-hop wireless communication system are provided. A first BS transmits a signal including a first common information codeword and a first private information codeword. A second BS transmits a signal including a second common information codeword and a second private information codeword. A first RS joint-decodes the first common information codeword and the second common information codeword and decodes the first private information codeword. A second RS joint-decodes the first common information codeword and the second common information codeword and decodes the second private information codeword.

Claims

1. A multi-hop wireless communication system comprising:

a first Base Station (BS) for transmitting a signal comprising a first common information codeword and a first private information codeword to a first Radio Station (RS) and a second RS;

a second BS for transmitting a signal comprising a second common information codeword and a second private information codeword to the first RS and the second RS;

the first RS for joint-decoding the first common information codeword and the second common information codeword and decoding the first private information codeword; and

the second RS for joint-decoding the first common information codeword and the second common information codeword and decoding the second private information codeword.

2. The system of claim 1, wherein transmit powers of the first private information codeword and the second private information codeword are determined in Equation below:

$P_{1<br><br>p}=\min <br><br>\left(\frac{k_1}{{<br><br>h_{12}<br><br>}^2},P_1\right),<br><br>P_{2<br><br>p}=\min <br><br>\left(\frac{k_1}{{<br><br>h_{21}<br><br>}^2},P_2\right)$

where,

P_1p;

transmit power of first private information codeword,

P_2p;

transmit power of second private information codeword,

h₁₂;

channel coefficient between first BS and second RS,

P₁;

maximum transmit power of first BS,

h₂₁;

channel coefficient between second BS and first RS,

P₂;

maximum transmit power of second BS, and

k₁;

transmit power weight.

3. The system of claim 1, wherein transmit powers of the first common information codeword and the second common information codeword are determined in Equation below:

P_1c=P₁−

P_1p, P_2c=P₂−

P_2p

where,

P_1c;

first common information codeword transmit power,

P_2c;

second common information codeword transmit power,

P₁;

maximum transmit power of first BS,

P₂;

maximum transmit power of second BS,

P_1p;

transmit power of first private information codeword, and

P_2p;

transmit power of second private information codeword.

4. The system of claim 1, wherein the first RS transmits a signal comprising a third common information codeword and a third private information codeword to a first MS and a second MS,

wherein the second RS transmits a signal comprising a fourth common information codeword and a fourth private information codeword to the first MS and the second MS, and

further comprising:

the first MS for joint-decoding the third common information codeword and the fourth common information codeword and then, decoding the third private information codeword; and

the second MS for joint-decoding the third common information codeword and the fourth common information codeword and then, decoding the fourth private information codeword.

5. The system of claim 4, wherein the third private information is comprised of x_1pc and x_1pp, and

wherein the fourth private information is comprised of x_2pc, and x_2pp.

6. The system of claim 4, wherein transmit powers of the third common information codeword, the third private information codeword, the fourth common information codeword, and the fourth private information codeword are determined in Equation below:

x′

_1c;

α

₁Q₁, x_1pc;

α

₁Q₁−

(1−

α

₁)α

₂Q₁, x_1pp;

(1−

α

₁)α

₂Q₁

x′

_2c;

α

₂Q₂, x_2pc;

α

₂Q₂−

(1−

α

₂)α

₁Q₂, x_2pp;

(1−

α

₂)α

₁Q₂

where,

x′

_1c;

third common information codeword,

x′

_2c;

fourth private information codeword,

α

₁;

transmit power coefficient of third common information codeword, and real number between ‘

0’ and

‘

1’

,

α

₂;

transmit power coefficient of fourth common information codeword, and real number between ‘

0’ and

‘

1’

,

Q₁;

maximum transmit power of first RS, and

Q₂;

maximum transmit power of second RS.

7. The system of claim 1, wherein the first RS encodes the first common information, generates a third common information codeword by performing Dirty Paper Coding (DPC) using the second common information, and transmits a signal comprising the third common information codeword and a third private information codeword to a first MS and a second MS, and

wherein the second RS encodes the first common information, generates a fourth common information codeword by performing DPC using the second common information, and transmits a signal comprising the fourth common information codeword and a fourth private information codeword to the first MS and the second MS.

8. The system of claim 7, wherein the third private information is comprised of x_1pc and x_1pp, and

wherein the fourth private information is comprised of x_2pc and x_2pp.

9. The system of claim 8, further comprising:

the first MS for joint-decoding the x_1pc comprised in the third private information and the x_2pc comprised in the fourth private information and then, decoding the x_1pp comprised in the third private information; and

the second MS for joint-decoding the x_1pc comprised in the third private information and the x_2pc comprised in the fourth private information and then, decoding the x_2pp comprised in the fourth private information.

10. The system of claim 9, wherein transmit powers of the third common information codeword, the third private information codeword, the fourth common information codeword, and the fourth private information codeword are determined in Equation below:

x_1c;

α

₁Q₁, x_2c;

α

₂Q₂, x_1pc;

α

₃γ

₁Q₁, x_1pp;

α

₃γ

₂Q₁;

1st RS

x_1c;

β

₂Q₂, x_2c;

β

₂Q₂, x_2pc;

β

₃δ

₁Q₁, x_2pp;

β

₃δ

₂Q₁;

2nd RS

(Σ

α

_i=1, Σ

γ

_j=1, 0≦

α

_i≦

1, 0≦

γ

_j≦

1,i=1,2,3, j=1,2)

(Σ

β

_i=1, Σ

δ

_j=1, 0≦

β

_i≦

1, 0≦

δ

_j≦

1, i=1,2,3, j=1,2)

where,

x_jc;

common information codeword transmitted by RSj,

x_jpc and x_jpp;

private information transmitted by RSj, and

α

_j, β

_j, γ

_j, and δ

_j;

arbitrary variables.

11. An operation method of a Base Station (BS) in a multi-hop wireless communication system, the method comprising:

transmitting a signal comprising a first common information codeword and a second private information codeword to a first Radio Station (RS) and a second RS.

12. The method of claim 11, wherein transmit powers of the first private information codeword and the second private information codeword are determined in Equation below:

$P_{1<br><br>p}=\min <br><br>\left(\frac{k_1}{{<br><br>h_{12}<br><br>}^2},P_1\right),<br><br>P_{2<br><br>p}=\min <br><br>\left(\frac{k_1}{{<br><br>h_{21}<br><br>}^2},P_2\right)$

where,

P_1p;

transmit power of first private information codeword,

P_2p;

transmit power of second private information codeword,

h₁₂;

channel coefficient between first BS and second RS,

P₁;

maximum transmit power of first BS,

h₂₁;

channel coefficient between second BS and first RS,

P₂;

maximum transmit power of second BS, and

k₁;

transmit power weight.

13. The method of claim 11, wherein transmit powers of the first common information codeword and the second common information codeword are determined in Equation below:

P_1c=P₁−

P_1p, P_2c=P₂−

P_2p

where,

P_1c;

first common information codeword transmit power,

P_2c;

second common information codeword transmit power,

P₁;

maximum transmit power of first BS,

P₂;

maximum transmit power of second BS,

P_1p;

transmit power of first private information codeword, and

P_2p;

transmit power of second private information codeword.

14. An operation method of a Radio Station (RS) in a multi-hop wireless communication system, the method comprising:

joint-decoding a first common information codeword received from a first Base Station (BS) and a second common information codeword received from a second BS; and

decoding a first private information codeword.

15. The method of claim 14, further comprising transmitting a signal comprising a third private information codeword comprised of x_1pc and x_1pp and a third common information codeword to a first Mobile Station (MS) and a second MS.

16. The method of claim 15, wherein transmit powers of the third common information codeword and the third private information codeword are determined in Equation below:

x′

_1c;

α

₁Q₁, x_1pc;

α

₁Q₁−

(1−

α

₁)α

₂Q₁, x_1pp;

(1−

α

₁)α

₂Q₁

where,

x′

_1c;

third common information codeword,

α

₁;

transmit power coefficient of third common information codeword, and real number between ‘

0’ and

‘

1’

, and

Q₁;

maximum transmit power of RS.

17. The method of claim 14, further comprising:

encoding the first common information, and generating a third common information codeword by performing Dirty Paper Coding (DPC) using the second common information; and

transmitting a signal comprising a third private information codeword comprised of x_1pc and x_1pp and the third common information codeword to a first MS and a second MS.

18. The method of claim 17, wherein transmit powers of the third common information codeword and the third private information codeword are determined in Equation below:

x_1c;

α

₁Q₁, x_2c;

α

₂Q₂, x_1pc;

α

₃γ

₁Q₁, x_1pp;

α

₃γ

₂Q₁

(Σ

α

_i=1, Σ

γ

_j=1, 0≦

α

_i≦

1, 0≦

γ

_j≦

1, i=1,2,3, j=1,2)

where,

x_jc;

common information codeword transmitted by RSj,

x_jpc and x_jpp;

private information transmitted by RSj, and

α

_j, β

_j, γ

_j, and δ

_j;

arbitrary variables.

19. An operation method of a Mobile Station (MS) in a multi-hop wireless communication system, the method comprising:

receiving a signal comprising a first private information codeword comprised of x_1pc and x_1pp and a first common information codeword transmitted by a first RS, and a signal comprising a first private information codeword comprised of x_2pc and x_2pp and a first common information codeword transmitted by a second RS;

joint-decoding the first common information codeword and the second common information codeword;

joint-decoding the x_1pc and x_2pc; and

decoding the x_1pp.