Method and apparatus for separated connections of uplink and downlink

1. An operating method of a terminal performed by the terminal, the method comprising:

receiving a downlink reference signal from each of base stations;

updating an uplink base station candidate group by adding the base stations to the uplink base station candidate group;

measuring a strength of the downlink reference signal;

selecting a first base station from among the base stations based on the measured strength;

establishing a downlink cell association with the first base station;

transmitting an uplink reference signal to the base stations in the uplink base station candidate group;

receiving an identifier of a second base station providing an uplink from the first base station through a downlink, wherein the second base station is selected from among the base stations by the first base station; and

establishing an uplink cell association with the second base station based on the identifier of the second base station.

2. The method of claim 1 , wherein the first base station determines the second base station based on a strength of the uplink reference signal and a bias factor transmitted from each of the base stations.

3. The method of claim 1 , wherein the uplink reference signal comprises an identifier of the first base station and an identifier of the terminal.

4. The method of claim 1 , further comprising:

communicating using the uplink and the downlink,

wherein the terminal receives downlink control information for the downlink through a downlink control channel of the first base station and receives uplink control information for the uplink through a downlink control channel of the second base station.

5. A non-transitory computer-readable recording medium comprising a program to implement the method of claim 1 .

6. An operating method of a base station performed by the base station, the method comprising:

transmitting a downlink reference signal to a terminal;

establishing a downlink cell association with the terminal, wherein the base station is determined to a downlink station by the terminal based on a strength of the downlink reference signal;

receiving a strength of an uplink reference signal from each base station, wherein the uplink reference signal is transmitted from the terminal to the each base station, the strength of an uplink reference signal is measured by the each base station;

determining an uplink base station providing an uplink to the terminal based on the strength of the uplink reference signal; and

transmitting an identifier of the determined uplink base station to the terminal.

7. The method of claim 6 , wherein the determining is performed based on the uplink reference signal and a bias factor transmitted from each base station.

8. The method of claim 7 , wherein the bias factor is determined based on at least one of an average transmission rate of each base station and an average transmission rate of the terminal.

9. The method of claim 6 , wherein the strength of the uplink reference signal is transmitted to the base station through a backhaul network between the base station and each base station.

10. A non-transitory computer-readable recording medium comprising a program to implement the method of claim 6 .

11. A terminal, comprising:

a processing unit; and

a networking unit,

wherein the networking unit receives downlink reference signal from each of base stations,

wherein the processing unit updates an uplink base station candidate group by adding the base stations to the uplink base station candidate group;

wherein the processing unit measures a strength of the downlink reference signal, selects a first base station from among the base stations based on the measured strength, and establishes a downlink cell association with the first base station through the networking unit,

wherein the networking unit transmits an uplink reference signal to the base stations, and receives an identifier of a second base station providing an uplink from the first base station through a downlink,

wherein the second base station is selected from among the base stations by the first base station, and

wherein the processing unit establishes an uplink cell association with the second base station through the networking unit based on the identifier of the second base station.

12. The terminal of claim 11 , wherein the first base station determines the second base station based on a strength of the uplink reference signal and a bias factor transmitted from each base station.

13. The terminal of claim 11 , wherein the uplink reference signal comprises an identifier of the first base station and an identifier of the terminal.

14. The terminal of claim 11 , wherein the processing unit communicates using the uplink and the downlink through the networking unit, and

wherein the terminal receives downlink control information for the downlink through a downlink control channel of the first base station and receives uplink control information for the uplink through a downlink control channel of the second base station.

15. A base station, comprising:

a processing unit; and

a networking unit,

wherein the networking unit transmits a downlink reference signal to a terminal,

wherein the processing unit establishes a downlink cell association with a terminal through the networking unit,

wherein the base station is determined to a downlink station by the terminal based on a strength of the downlink reference signal,

wherein the networking unit receives a strength of an uplink reference signal from each base station,

wherein the uplink reference signal is transmitted from the terminal to the each base station, the strength of an uplink reference signal is measured by the each base station,

wherein the processing unit determines an uplink base station providing an uplink to the terminal based on the strength of the uplink reference signal, and

wherein the networking unit transmits an identifier of the determined uplink base station to the terminal.

16. The base station of claim 15 , wherein the processing unit determines the uplink base station based on the strength of the uplink reference signal and a bias factor transmitted from each base station.

17. The base station of claim 16 , wherein the bias factor is determined based on at least one of an average transmission rate of each base station and an average transmission rate of the terminal.

18. The base station of claim 15 , wherein the strength of the uplink reference signal is transmitted to the base station through a backhaul network between the base station and each base station.