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

• US 8,345,787 B2
• Filed: 04/02/2009
• Issued: 01/01/2013
• Est. Priority Date: 04/02/2008
• Status: Expired due to Fees

• 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: Yu, Tak-Ki, Kim, Eun-Yong, Lee, Sang-Min, Cho, Myeon-Kyun, Chung, Sae-Young, Choi, Sang Won
• Primary Examiner(s): Liu, Shuwang
• Assistant Examiner(s): TAYONG, HELENE E
• Application Number:
  US12/384,286
• Publication Number:
  US 20090252243A1
• Time in Patent Office: 1,370 Days
• Field of Search: 375/267, 375/260, 375/346, 375/348, 370/335, 370/315, 370/492, 455/11.1, 455/15, 455/63.1, 455/114.2, 714/48, 714/799
• US Class Current: 375/267
• 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) configured to transmit a signal comprising a first common information codeword and a first private information codeword to a first Relay Station (RS) and a second RS, wherein the first common information codeword is a codeword transmitted to all RSs and the first private information codeword is a codeword transmitted only to the first RS;

a second BS configured to transmit a signal comprising a second common information codeword and a second private information codeword to the first RS and the second RS, wherein the second common information codeword is a codeword transmitted to all RSs and the second private information codeword is a codeword transmitted only to the second RS;

the first RS configured to joint-decode the first common information codeword and the second common information codeword and to decode the first private information codeword, wherein the second private information codeword comprises interference for the first RS; and

the second RS configured to joint-decode the first common information codeword and the second common information codeword and to decode the second private information codeword, wherein the first private information codeword comprises interference for the second RS.

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:

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 is further configured to transmit a signal comprising a third common information codeword and a third private information codeword to a first Mobile Station (MS) and a second MS, wherein the second RS is further configured to transmit 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, wherein the first MS is configured to joint-decode the third common information codeword and the fourth common information codeword and to decode the third private information codeword; and

the second MS, wherein the second MS is configured to joint-decode the third common information codeword and the fourth common information codeword and to decode the fourth private information codeword.

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

_l;

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 is further configured to encode the first common information codeword, to generate a third common information codeword by performing Dirty Paper Coding (DPC) using the second common information codeword, and to transmit 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 is further configured to encode the first common information codeword, to generate a fourth common information codeword by performing DPC using the second common information codeword, and to transmit 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 codeword is comprised of x_1pc and x_1pp, and wherein the fourth private information codeword is comprised of x_2pc and x_2pp.

9. The system of claim 8, further comprising:

the first MS, wherein the first MS is configured to joint-decode the x_1pc comprised in the third common information codeword and the x_2pc comprised in the fourth common information codeword and to decode the x_1pp comprised in the third private information codeword; and

the second MS, wherein the second MS is configured to joint-decode the x_1pc comprised in the third common information codeword and the x_2pc comprised in the fourth common information codeword and to decode the x_2pp comprised in the fourth private information codeword.

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 codeword transmitted by RSj, and α

_j, β

_jγ

_j, and δ

_j;

arbitrary variables.

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

transmitting, at the first BS, a signal comprising a first common information codeword and a first private information codeword to a first Relay Station (RS) and a second RS,

wherein the first common information codeword is a codeword transmitted to all RSs and the first private information codeword is a codeword transmitted only to the first RS,

wherein the first RS comprises a target node for the first private information codeword, the second RS comprises a target node for a second private information codeword transmitted by a second BS, the second private information codeword comprises interference for the first RS, and the first private information codeword comprises interference for the second RS, and

wherein the first RS joint-decodes the first common information codeword received from the first BS and a second common information codeword received from the second BS, wherein the second common information codeword is a codeword transmitted to all RSs and the second private information codeword is a codeword transmitted only to the 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:

13. The method of claim 11, wherein the second common information codeword is transmitted by the second BS, and 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 first Relay Station (RS) in a multi-hop wireless communication system, the method comprising:

joint-decoding, at the first RS, a first common information codeword received from a first Base Station (BS) and a second common information codeword received from a second BS, wherein the first common information codeword and the second common information codeword are codewords transmitted to all RSs;

decoding, at the first RS, a first private information codeword received from the first BS; and

transmitting, at the first RS, a signal comprising a third private information codeword comprised of x_1pc and x_1pp and a third common information codeword comprising x′

_1c to a first Mobile Station (MS) and a second MS,

wherein the first RS comprises a target node for the first private information codeword, a second RS comprises a target node for a second private information codeword transmitted by a second BS, the second private information codeword is a codeword transmitted only to the second RS and comprises interference for the first RS, and the first private information codeword is a codeword transmitted only to the first RS and comprises interference for the second RS.

15. The method of claim 14, 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.

16. The method of claim 14, further comprising:

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

17. The method of claim 16, 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 codeword transmitted by RSj, and

α

_j, β

_j, γ

_j, and δ

_j;

arbitrary variables.

18. 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 Relay Station(RS), and a signal comprising a second private information codeword comprised of x_2pc and X_2pp and a second common information codeword transmitted by a second RS, wherein the first common information codeword and the second common information codeword are codewords transmitted to all RSs, the first private information codeword is a codeword transmitted only to the first RS and the second private information codeword is a codeword transmitted only to the 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, wherein the second private information codeword comprises interference for the first RS, and the first private information codeword comprises interference for the second RS.

19. The method of claim 18, wherein the signal transmitted by the first RS is encoded by the first RS with Dirty Paper Coding based on the second common information codeword.