Apparatus and method for adaptive channel transmission using channel state

1. A method for channel transmission of a remote node, the method comprising:

intermittently receiving a forward channel transmitted from a host node,

wherein the receiving of the forward channel comprises,

measuring a state of the forward channel for a first period by enabling an operation of a receiver of the remote note for the first period, and failing to measure the state of the forward channel for a second period by disabling the operation of the receiver for the second period,

wherein the first period and the second period are arranged repetitively in a flow of time and a measurement cycle of the state of the forward channel is adjusted based on the received forward channel;

estimating a state of a reverse channel from the remote node to the host node based on the received forward channel;

determining whether the estimated state of the reverse channel satisfies a preset channel condition; and

adaptively transmitting the reverse channel based on the determined result.

2. The method according to claim 1 , wherein the failing to measure the state of the forward channel for the second period further comprises powering off a majority of blocks of the remote node for the second period.

3. The method according to claim 1 , wherein a time interval between the plurality of first periods arranged repetitively is variably set based on at least one of a Doppler frequency of the received forward channel, a time allowed to transmit the reverse channel, an elapsed time from the time of occurrence of an event that aims to transmit the reverse channel, a required level of a set quality of service (QoS), or a request from the host.

4. The method according to claim 3 , wherein the measurement cycle of the state of the forward channel is set based on at least one of in inverse proportion to the Doppler frequency of the received forward channel, in proportion to the time allowed to transmit the reverse channel, in inverse proportion to the time of occurrence of the event that aims to transmit the reverse channel, in inverse proportion to the required level of the set quality of service (QoS).

5. The method according to claim 1 , wherein the receiving of the forward channel comprises:

setting a next measurement time;

comparing the set next measurement time to a present time;

measuring the state of the forward channel by enabling the operation of the receiver, when the next measurement time corresponds to the present time; and

stopping, by the remote node, the operation of the receiver and standing by for a predetermined time, when the next measurement time does not correspond to the present time,

wherein the comparing repeats after the standby for the predetermined time.

6. The method according to claim 1 , wherein a transmission power for transmitting the reverse channel is determined by estimating the state of the reverse channel through measurement of a pilot channel included in the transmitted forward channel.

7. The method according to claim 1 , wherein the reverse channel is a random access channel (RACH), and the remote node is a wireless communication terminal in conformity with a time division duplex (TDD) scheme.

8. A method for channel transmission of a remote node, the method comprising:

receiving a forward channel transmitted from a host node,

wherein the receiving of the forward channel comprises,

measuring a state of the forward channel for a first period by enabling an operation of a receiver of the remote note for the first period, and failing to measure the state of the forward channel for a second period by disabling the operation of the receiver for the second period,

wherein the first period and the second period are arranged repetitively in a flow of time and a measurement cycle of the state of the forward channel is adjusted based on the received forward channel;

estimating a state of a reverse channel from the remote node to the host node based on the received forward channel;

determining whether the estimated state of the reverse channel satisfies a preset channel condition; and

adaptively transmitting the reverse channel based on the determined result,

wherein the channel condition is variably reset over time.

9. The method according to claim 8 , wherein the channel condition is changed and set such that a transmission probability of the reverse channel becomes relatively higher over time.

10. The method according to claim 8 , wherein a threshold representing the channel condition is variably set based on at least one of a Doppler frequency of the received forward channel, a time allowed to transmit the reverse channel, an elapsed time from the time of occurrence of an event that aims to transmit the reverse channel, a required level of a set quality of service (QoS), or a request from the host.

11. A remote node, comprising:

a receiving unit to intermittently receive a forward channel transmitted from a host node,

wherein the receiving unit measures a state of the forward channel by enabling an operation of the receiving unit for only a first period and does not measure the state of the forward channel by disabling the operation of the receiving unit for a second period,

wherein the first period and the second period are arranged repetitively in a flow of time and a measurement cycle of the state of the forward channel is adjusted based on the received forward channel;

a channel estimating unit to estimate a state of a reverse channel from the remote node to the host node based on the received forward channel;

a control unit to determine whether the estimated state of the reverse channel satisfies a preset channel condition and determine whether to transmit the reverse channel based on the determined result; and

a transmitting unit to adaptively transmit the reverse channel based on the determination of the control unit.

12. The remote node according to claim 11 , wherein a minimum measurement frequency of the state of the forward channel is determined based on a Doppler frequency of the forward channel.

13. The remote node according to claim 11 , wherein a time interval between the plurality of first periods arranged repetitively is variably set based on at least one of a Doppler frequency of the received forward channel, a time allowed to transmit the reverse channel, an elapsed time from the time of occurrence of an event that aims to transmit the reverse channel, a required level of a set quality of service (QoS), or a request from the host.

14. The remote node according to claim 12 , wherein minimum power consumption is maintained for the second period during which the receiving unit fails to operate.

15. The remote node according to claim 11 , wherein the control unit controls the receiving unit by determining an operating cycle of the receiving unit based on a determining parameter, and the determining parameter is at least one of a Doppler frequency of the received forward channel, a time allowed to transmit the reverse channel, an elapsed time from the time of occurrence of an event that aims to transmit the reverse channel, a required level of a set quality of service (QoS), or a request from the host.

16. The remote node according to claim 15 , wherein the determining parameter is received from the host or inputted by a user from an outside of the remote node.

17. The remote node according to claim 15 , wherein the determining parameter is calculated by the control unit based on the received forward channel and at least one preset constraint condition.

18. The remote node according to claim 11 , wherein the channel condition is variably reset over time.

19. The remote node according to claim 11 , wherein the control unit determines whether to transmit the reverse channel by comparing a state estimate of the reverse channel calculated based on a channel gain of the received forward channel to a threshold representing the channel condition.

20. The remote node according to claim 11 , wherein a threshold representing the channel condition is variably set based on at least one of a Doppler frequency of the received forward channel, a time allowed to transmit the reverse channel, an elapsed time from the time of occurrence of an event that aims to transmit the reverse channel, a required level of a set quality of service (QoS), or a request from the host.