Data transmission and reception method and device using caching in wireless communication system performing comp

1. A method of transmitting data by a base station (BS) in a wireless communication system for performing a CoMP operation using a cache, the method comprising:

determining a transmission mode among a plurality of transmission modes based on at least one data stored in the cache;

determining data to be transmitted in the transmission mode; and

transmitting the data based on a cooperative transmission beamforming vector and the determined transmission mode,

wherein the transmission mode comprises a first mode for cooperatively performing data transmission between cooperative BSs, a second mode for sharing channel information between the cooperative BSs and cooperatively performing scheduling, and a third mode obtained by combining the first mode and the second mode,

wherein the cooperative transmission beamforming vector of the transmitted data is determined such that data transmission power is minimized while satisfying minimum SINR (Signal to Interference plus Noise Ratio) required by a reception user equipment (UE), and

wherein the cooperative transmission beamforming vector is determined to satisfy a following condition;

the condition is

min

V

U

k

⁢

∑

k

=

1

k

⁢



V

G

k



2

s

.

t

.

⁢



U

k

H

⁢

H

k

,

G

k

⁢

V

G

k

⁢



2

∑

j

≠

k

⁢



U

k

H

⁢

H

k

,

G

i

⁢

V

G

i



2

+



U

k

H

⁢

n

k



2

≥

2

μ

π

k

-

1

;

and

the V G k is a cooperative transmission beamforming vector formed by BSs that cooperate with each other in order to transmit information to a k th UE, U k is a reception beamforming vector of a k th UE, H k,G k is a channel gain between corresponding cooperative BSs and a k th UE, n k′ is noise of a k th UE reception end, and μ l′ is minimum spectrum efficiency required to detect l th data.

2. The method according to claim 1 , wherein, when the at least one data stored in the cache comprises data requested by the reception UE of each of the cooperative BSs, the transmission mode is determined as the first mode.

3. The method according to claim 1 , wherein, when the at least one data stored in the cache does not comprise at least one of data requested by the reception UE of each of the cooperative BSs, the transmission mode is determined as the second mode or the third mode.

4. The method according to claim 3 , wherein:

the data is determined as data with a largest number of stored parity bits of the at least one data stored in the cache; and

a transmission mode of the data is the third mode.

5. The method according to claim 4 , wherein, according to the third mode, when a serving cell of a UE that makes a request for the data is the BS, the BS operates in the first mode, and when the serving cell of the UE that makes a request for the data is not the BS, the BS operates in the second mode.

6. The method according to claim 1 , wherein the at least one data is encoded based on maximum distance separable (MDS) coding.

7. The method according to claim 1 , further comprising:

encoding data stored in the cache to a parity bit; and

modulating the parity bit based on adaptive modulation and coding.

8. The method according to claim 1 , wherein the first mode is an operation mode for performing joint processing and the second mode is an operation mode for performing cooperative scheduling and beamforming.

9. A method of receiving data by a user equipment (UE) in a wireless communication system for performing a CoMP operation using a cache, the method comprising:

receiving a parity bit of data based on a cooperative transmission beamforming vector from a serving base station (BS) that operates in a specific transmission mode among a plurality of transmission modes; and

restoring the data from the parity bit,

wherein the plurality of transmission modes comprise a first mode for cooperatively performing data transmission between cooperative BSs, a second mode for sharing channel information between the cooperative BSs and cooperatively performing scheduling, and a third mode obtained by combining the first mode and the second mode,

wherein the cooperative transmission beamforming vector of the transmitted data is determined such that data transmission power is minimized while satisfying minimum SINR (Signal to Interference plus Noise Ratio) required by the UE, and

wherein the cooperative transmission beamforming vector is determined to satisfy a following condition;

the condition is

min

V

G

k

⁢

∑

k

=

1

K

⁢



V

G

k



2

s

.

t

.

⁢



U

k

H

⁢

H

k

,

G

k

⁢

V

G

k



2

∑

j

≠

k

⁢



U

k

H

⁢

H

k

,

G

j

⁢

V

G

j



2

+



U

k

H

⁢

n

k



2

≥

2

μ

π

k

-

1

;

and

the V G k is a cooperative transmission beamforming vector formed by BSs that cooperate with each other in order to transmit information to a k th UE, U k is a reception beamforming vector of a k th UE, H k,G k is a channel gain between corresponding cooperative BSs and a k th UE, n k′ is noise of a k th UE reception end, and μ l′ is minimum spectrum efficiency required to detect l th data.

10. A base station (BS) for transmitting data in a wireless communication system for performing a CoMP operation using a cache, the BS comprising:

a processor configured to determine a transmission mode among a plurality of transmission modes based on at least one data stored in the cache and to determine data to be transmitted in the transmission mode; and

a transmitter configured to transmit the data based on a cooperative transmission beamforming vector and the determined transmission mode,

wherein the transmission mode comprises a first mode for cooperatively performing data transmission between cooperative BSs, a second mode for sharing channel information between the cooperative BSs and cooperatively performing scheduling, and a third mode obtained by combining the first mode and the second mode,

wherein the cooperative transmission beamforming vector of the transmitted data is determined such that data transmission power is minimized while satisfying minimum SINR (Signal to Interference plus Noise Ratio) required by a reception user equipment (UE), and

wherein the cooperative transmission beamforming vector is determined to satisfy a following condition;

the condition is

min

V

G

k

⁢

∑

k

=

1

K

⁢



V

G

k



2

s

.

t

.

⁢



U

k

H

⁢

H

k

,

G

k

⁢

V

G

k



2

∑

j

≠

k

⁢



U

k

H

⁢

H

k

,

G

j

⁢

V

G

j



2

+



U

k

H

⁢

n

k



2

≥

2

μ

π

k

-

1

;

and

the V G k is a cooperative transmission beamforming vector formed by BSs that cooperate with each other in order to transmit information to a k th UE, U k is a reception beamforming vector of a k th UE, H k,G k is a channel gain between corresponding cooperative BSs and a k th UE, n k′ is noise of a k th UE reception end, and μ l′ is minimum spectrum efficiency required to detect l th data.

11. A user equipment (UE) for receiving data in a wireless communication system for performing a CoMP operation using a cache, the UE comprising:

a receiver configured to receive a parity bit of data based on a cooperative transmission beamforming vector from a serving base station (BS) that operates in a specific transmission mode among a plurality of transmission modes; and

a processor configured to restore the data from the parity bit,

wherein the plurality of transmission modes comprise a first mode for cooperatively performing data transmission between cooperative BSs, a second mode for sharing channel information between the cooperative BSs and cooperatively performing scheduling, and a third mode obtained by combining the first mode and the second mode,

wherein the cooperative transmission beamforming vector of the transmitted data is determined such that data transmission power is minimized while satisfying minimum SINR (Signal to Interference plus Noise Ratio) required by the UE, and

wherein the cooperative transmission beamforming vector is determined to satisfy a following condition;

the condition is

min

V

G

k

⁢

∑

k

=

1

K

⁢



V

G

k



2

s

.

t

.

⁢



U

k

H

⁢

H

k

,

G

k

⁢

V

G

k



2

∑

j

≠

k

⁢



U

k

H

⁢

H

k

,

G

j

⁢

V

G

j



2

+



U

k

H

⁢

n

k



2

≥

2

μ

π

k

-

1

;

and

the V G k is a cooperative transmission beamforming vector formed by BSs that cooperate with each other in order to transmit information to a k th UE, U k is a reception beamforming vector of a k th UE, H k,G k is a channel gain between corresponding cooperative BSs and a k th UE, n k′ is noise of a k th UE reception end, and μ l′ is minimum spectrum efficiency required to detect l th data.