WO2006083152A1

WO2006083152A1 - A method of scheduling uplink channel of a mobile station that is in soft handover in a mobile wireless communication system

Info

Publication number: WO2006083152A1
Application number: PCT/KR2006/000446
Authority: WO
Inventors: Joon Kui Ahn; Bong Hoe Kim; Dong Youn Seo; Hak Seong Kim; Dong Wook Roh
Original assignee: Lg Electronics Inc.
Priority date: 2005-02-07
Filing date: 2006-02-07
Publication date: 2006-08-10
Also published as: KR20060090065A; CN101116350B; CN101116350A; KR101084128B1

Abstract

A method of scheduling uplink channel of a mobile station (MS) that is in soft handover in a wireless mobile communication system is disclosed. More specifically, the MS receives a plurality of scheduling commands from a non-serving cell and determines whether a specified condition is satisfied from the received scheduling commands. Thereafter, the MS adjusts a maximum transmission power when the specified condition is satisfied.

Description

A METHOD OF SCHEDULING UPLINK CHANNEL OF A MOBILE

STATION THAT IS IN SOFT HANDOVER IN A MOBILE WIRELESS

COMMUNICATION SYSTEM

Technical Field

The present invention relates to a field of mobile wireless communication, and

more particularly, to a method of scheduling uplink channel of a mobile terminal that

is in soft handover. Although the present invention is suitable for a wide scope of

applications, it is particularly suitable for preventing ping pong effect caused by

conflicting scheduling commands between a serving cell and a non-serving cell.

Background Art

In recent years, demand for transmitting data having greater capacity at higher

speeds in the wireless mobile communication system has been increasing. To

accommodate such an increase in demand, there is increasing number of discussions

related to various methods for transmitting high speed data packets in the uplink

direction from a user equipment (UE), also called a mobile station (MS), to Node B,

also called a base station (BS).

As an example of one of the various methods under discussion in a 3^rd

Generation Partnership Program Wide Code Division Multiple Access (3GPP

WCDMA), an Enhanced uplink Dedicated Channel (E-DCH) has been proposed. The E-DCH is a transmission channel that corresponds to High Speed downlink Shared

Channel (HS-DSCH). Moreover, the E-DCH can respond to the demand for high speed

downlink transmission. In addition, the E-DCH can be used to enhance efficiency by

incorporating schemes such as Node B uplink packet scheduling to the uplink

Dedicated Channel (DCH) of the existing 3GPP WCDMA and a Hybrid-Auto

Retransmission reQuest (HARQ) of the physical layer.

In detail, the HARQ scheme includes performing higher layer retransmission

operations in the physical layer. In operation, the HARQ scheme combines Automatic

Repeat reQuest (ARQ) protocols with Forward-Error-Correcting (FEC) schemes. That

is, the error-generated data packets are held (not discarded), and then transmitted after

being combined in the retransmitted data packets. The HARQ scheme can improve the

system throughput by enhancing ARQ with error correcting ability of FEC. In the

HARQ scheme, a successful reception of uplink data transmission using the HARQ is

indicated by an Acknowledgment (ACK) signal or a Negative ACK (NACK). More

specifically, the MS transmits the ACK signal to Node B if the transmitted data packet

is successfully received. On the contrary, the MS transmits the NACK signal to Node

B if transmission is unsuccessful.

Traditionally, a Radio Network Controller (RNC) controls noise rise. However,

in BS controlled scheduling, the BS controls noise rise, not the RNC, in order to

increase uplink transmission capacity. The purpose and rationale for BS controlled

scheduling is that the BS can respond to noise rise more quickly than the RNC. Thus, noise rise can. be managed more efficiently, and as a result increase uplink transmission

capacity.

When the MS is in soft handover, the cells in an active set can be classified into

two types. According to the first type, the cell is referred to as a serving cell. The

service cell encompasses a scheduling entity. According to the second type, the cell is

referred to as a non-servicing cell, which lacks a scheduling entity.

Referring to the first type, a BS in the serving cell, also referred to as a serving

BS, transmits scheduling command to the MS. The scheduling command can be

defined by two types. The first type refers to an Absolute Grant (AG) which provides a

maximum transmission power (or rate) by which the MS can send transmission. The

second type refers to a Relative Grant (RG) which provides a change in power (or rate)

relative to the current transmission power (or rate).

In operation, the AG can be transmitted by all serving base stations. However,

the RG can be selectively transmitted or not transmitted by the serving station based on

the status of the MS. In more detail, the RG of the serving BS is represented by

'UP/DOWN' commands. Here, the 'UP' command refers to increasing the

transmission power by a specified amount while the 'DOWN' command refers to

decreasing the transmission power by a specified amount.

During soft handover by the MS, the signals transmitted from the MS can affect

the interference level of the non-serving cell. Here, the interference occurs because the

MS in soft handover is actively communicating with all the cells in the active set. If the traffic load in the non-serving cell increases to affect the system operation, the non-

serving cell can transmit a scheduling command (i.e., RG) to the MS in soft handover.

In other words, the non-serving cell can transmit a scheduling command (i.e., RG)

scheduling operation for the MS belonging to the cell of the serving BS.

Furthermore, the non-serving cell transmits two types of RGs, namely, a

'DOWN' command and a Discontinuous Transmission (DTX) command. As discussed

above, the 'DOWN' command is used to decreasing the transmission power by a

specified amount. Here, if the serving BS is in mode for transmitting the RG, the MS

decreases the maximum transmission power a specified amount according to the

received 'DOWN' command. However, if the serving BS is in mode which is unable to

transmit the RG, the MS decrease the maximum transmission power a specified

amount from the maximum transmission power previously received via the AG. With

such commands, the interference level in the cell of the non-serving cell can be

controlled.

The scheduling operation of the MS in the soft handover according to the

related art has the following problems. After the MS down-adjusts the maximum

transmission power according to the RG from the non-serving cell (e.g., 'DOWN'

command), the serving BS may transmits its RG (i.e., 'UP' command). The reason for

this is that the serving BS may determine that the transmission power level of the

down-adjusted maximum transmission power is lower than the transmission power

desired by the MS. In such a case, as illustrated in Figure 1, the non-serving cell O

transmits a scheduling command to decrease the maximum transmission power rate

while the serving BS transmits a scheduling command to increase the maximum

transmission power. Consequently, two contrasting scheduling commands are

transmitted to the MS causing a ping-pong effect. That is, the MS adjusts the

maximum transmission power each and every time it receives the scheduling command

from the non-serving cell and from the serving BS. Therefore, it may be difficult for

the MS to maintain a stable transmission power.

Second, when the MS is in handover, an error rate is high for the MS receiving

the RG command from the non-serving cell. As such, the communication system

efficiency can suffer as a result. However, the related art does not have a solution to

respond to the problem of above.

Disclosure of the Invention

Accordingly, the present invention is directed to a method of scheduling uplink

channel of a mobile station that is in soft handover in a mobile wireless communication

system that substantially obviates one or more problems due to limitations and

disadvantages of the related art.

An object of the present invention is to provide a method of scheduling uplink

channel of a mobile station (MS) that is in soft handover in a wireless mobile

communication system is disclosed. Additional advantages, objects, and features of the invention will be set forth in

part in the description which follows and in part will become apparent to those having

ordinary skill in the art upon examination of the following or may be learned from

practice of the invention. The objectives and other advantages of the invention may be

realized and attained by the structure particularly pointed out in the written description

and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the

purpose of the invention, as embodied and broadly described herein, a method of

scheduling uplink channel of a mobile station (MS) that is in soft handover in a

wireless mobile communication system is disclosed. More specifically, the MS

receives a plurality of scheduling commands from a non-serving cell and determines

whether a specified condition is satisfied from the received scheduling commands.

Thereafter, the MS adjusts a maximum transmission power when the specified

condition is satisfied.

In another aspect of the present invention, a mobile station (MS) receives a

plurality of scheduling commands from a non-serving cell by the MS, wherein the

scheduling command is a relative grant (RG) command. Further, the MS determines

whether at least one of a first specified condition and a second specified condition is

satisfied from the received plurality of scheduling commands, wherein the first

specified condition is receiving a first specified number of RG commands, each

containing the same instruction, consecutively, and the second specified condition is receiving a second specified number of RG commands, each containing the same

instruction, during a specified period of time. Thereafter, the MS adjusts the maximum

transmission power when any one of the first specified condition and the second

specified condition is satisfied.

Yet, in another aspect of the present invention, a mobile station (MS) receives a

plurality of relative grant (RG) commands from a non-serving cell and determines

whether a first specified condition is satisfied from the received RG commands.

Thereafter, the MS adjusts the maximum transmission power when the first specified

condition is satisfied.

It is to be understood that both the foregoing general description and the

following detailed description of the present invention are exemplary and explanatory

and are intended to provide further explanation of the invention as claimed.

Brief Description of the Drawings

The accompanying drawings, which are included to provide a further

understanding of the invention and are incorporated in and constitute a part of this

application, illustrate embodiment(s) of the invention and together with the description

serve to explain the principle of the invention. In the drawings;

FIG. 1 illustrates an example of a ping-pong effect in a mobile station that is in

handover; FIG. 2 is a flowchart illustrating an example of an operation of the MS during

soft handover according to an embodiment of the present invention;

FIG. 3 is an exemplary diagram illustrating transmission of no signals from a

non-serving cell during a specified time period;

FIG. 4 illustrates an example where an adjusted maximum transmission power

is maintained for a specified time period after a specified condition is satisfied;

FIG. 5 illustrates an example where an adjusted maximum transmission power

is maintained for a specified time period after another specified condition is satisfied;

FIG. 6 illustrates an example where an adjusted maximum transmission power

is adjusted after a specified condition is satisfied during the specified time period in

reference to FIG. 4;

FIG. 7 illustrates an example where an adjusted maximum transmission power

reference to FIG. 5; and

FIG. 8 is an exemplary diagram illustrating transmission of RG commands to

maintain current transmission power during a specified time period.

Best Mode for Carrying Out the Invention

Reference will now be made in detail to the preferred embodiments of the

present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings

to refer to the same or like parts.

Figure 2 is a flowchart illustrating an example of an operation of the MS during

soft handover according to an embodiment of the present invention, hi Figure 2, the

MS receives a plurality of RG commands transmitted from a non-serving cell (S21).

Then, the MS determines whether the received RG commands satisfy a specified

condition (S22). If the RG commands satisfy the specified condition, then the MS

adjusts a maximum transmission power according to the RG command (S23). As

discussed above, a transmission rate can also be used in performing scheduling

operation.

According to the conventional art, the MS adjusts the maximum transmission

power each time the MS receives the RG command from the non-serving cell.

Therefore, the transmission power is adjusted according to the instruction included in

each RG command. In other words, with different commands from the serving BS and

the non-serving cell, the MS would constantly adjust the maximum transmission power

each time it receives the RG command.

However, according to the embodiment of the present invention, the MS

receives a plurality of RG commands from the non-serving cell. These RG commands

are compared against a specified condition to determine whether a specified number of

RG commands satisfy the specified condition. Here, the specified number of RG

commands is at least two RG commands. If the specified number of RG commands satisfies the specified condition, then the maximum transmission power is adjusted

accordingly.

The details of the specified condition will be later explained.

There can be two types of RG commands transmitted from the non-serving cell,

for example. The first type of RG command is a 'DOWN' command, which instructs

the MS to decrease or lower the maximum transmission power. The second type of RG

command is a 'KEEP' command, which either instructs the MS maintain the current

maximum transmission power or not transmit any instruction or signal to the MS. Here,

the DTX scheme can be employed to prevent transmissions. Therefore, if the 'KEEP'

command is received by the MS, then the current maximum transmission power is

maintained by the MS.

As discussed above, the MS determines whether the received RG commands

satisfy the specified condition. Here, the specified condition can be classified into three

types. The first type of the specified condition (hereinafter "first specified condition")

refers to receiving consecutively a specified number (Nl) of the RG commands (Nl),

each of which contain a same instruction (e.g., 'DOWN' command). The second type

(hereinafter "second specified condition") refers to receiving a specified number (N2)

of the RG commands, each of which contain the same instruction, within a specified

time period (Tl). The third type (hereinafter "third specified condition") refers to a

combination of the first type and the second type and can be satisfied by satisfying any one of the two types. Alternatively, the third type can be satisfied by first to satisfy the

any one of the two types.

When the specified condition is satisfied, the MS adjusts the maximum

transmission power. That is, according to the first specified condition, when the MS

receives consecutively Nl RG commands, each command containing instruction to

decrease the maximum transmission power (i.e., 'DOWN' command) from the non-

serving cell, then the MS down-adjusts or decreases the maximum transmission power.

For example, when the MS receives three (3) RG commands consecutively, the MS

adjusts (e.g., up or down) the maximum transmission power.

According to the second specified condition, when the MS receives N2 RG

commands, each command containing the same instruction to decrease the maximum

transmission power, during Tl from the non-serving cell, then the MS decreases the

maximum transmission power. For example, when the MS receives three (3) RG

commands during Tl, the MS adjusts (e.g., up or down) the maximum transmission

power. Here, N2 RG commands do not need to be received consecutively during Tl.

However, Nl RG commands can be received consecutively. That is, when the MS

receives N2 RG commands, containing the same 'DOWN' command, prior to the

expiration of Tl, preferably, the MS adjusts the maximum transmission power

accordingly.

Alternatively, when the MS receives Nl RG commands consecutively or N2

RG commands during Tl, wherein each RG command contains the same instruction to ^

maintain the current maximum transmission power (i.e., 'KEEP' command), then the

MS maintains the maximum transmission power without making any adjustments. In

the descriptions of above, the values of Nl and N2 can be same or different.

When the maximum transmission power (or rate) is adjusted according to the

RG command, the maximum transmission power is adjusted in increments or put

differently, by a specified amount. In other words, since the RG command can only

instruct the MS to either increase (e.g., 'UP' command) or decrease (e.g., 'DOWN'

command) or keep (e.g., 'KEEP' command) the transmission power, the maximum

transmission power is increased or decreased by a specified amount. Here, the

specified amount can be received by the MS at call establishment or after the call is

established via signaling from the network. Alternatively, the specified amount can be

a fixed value predetermined between the MS and the network.

Preferably, if there are at least two non-serving cells, the MS should process the

RG commands for each non-serving cell independently. That is, the MS should

determine the RG commands transmitted from a first non-serving cell against the

specified condition. At the same time, the MS should independently determine the RG

commands transmitted from a second non-serving cell against the specified condition

of the first non-serving cell.

As discussed above, contrary commands, such as 'DOWN' command from the

non-serving cell and 'UP' command from the serving BS, can cause a ping-pong effect to take place. Therefore, the system efficiency is negatively affected due to large

fluctuations in the uplink Rise over Thermal (RoT).

The embodiment explained above discusses a way to combat the ping-pong

effect by executing the RG command when the specified condition is satisfied.

Discussed below are additional embodiments by which to counter the ping pong effect.

Figure 3 is an exemplary diagram illustrating transmission of no signals from

the non-serving cell during a specified time period. More specifically, after the

maximum transmission power is decreased, the non-serving cell does not transmit any

RG commands for a specified time period. This specified time period can be labeled

Tkeep or T2. After Tkeep or T2 expires, the maximum transmission power can be

increased due to RG commands received from the serving BS. During T_ke_ep or T2, the

MS maintains the adjusted maximum transmission power.

hi order for the MS to maintain the maximum transmission power (or rate)

during Tkeep or T2, the RG command transmitted from the non-serving cell can include

an additional condition (e.g., a sub-command). The condition or the sub-command can

be an instruction(s) for the MS not to act or maintain the maximum transmission power

for a specified period of time (T2) as illustrated in Figure 4. That is, the instruction

would instruct the MS not to act or adjust the adjusted maximum transmission power

for the specified period of time (T2) after the maximum transmission power has been

adjusted according to the instruction in the RG commands. In Figure 4, after the MS

decreases the maximum transmission power upon satisfying the first specified condition (i.e., receiving consecutively Nl number of RG commands from the non-

serving cell), the MS maintains the down-adjusted maximum transmission power for

T2 regardless of the commands received from the serving BS during T2. After

expiration of T2, the MS can then execute the instruction from the serving BS, and in

this example, the instruction is to increase the maximum transmission power.

In the same vein, in Figure 5, after the MS decreases the maximum

transmission power upon satisfying the second specified condition (i.e., receiving Nl

number of RG commands from the non-serving cell during Tl), the MS maintains the

down-adjusted maximum transmission power for T2 regardless of the commands

received from the serving BS during T2. As in Figure 4, the RG command includes a

condition or a sub-command to maintain the adjusted maximum transmission power

for T2. After expiration of T2, the MS can then execute the instruction from the

serving BS, and in this example, the instruction is to increase the maximum

transmission power.

In Figures 4 and 5, the MS maintains the adjusted maximum transmission

power for T2 even if the serving BS transmits 'UP' command during T2. However, the

situation can change when it is the non-serving cell transmitting the RG commands.

In Figure 6, which refers to Figure 4, after the MS has adjusted the maximum

transmission power, the MS receives a specified number (N3) of 'DOWN' commands

consecutively from the non-serving cell during T2, thus again satisfying the first

specified condition. When the first specified condition is satisfied during T2, the MS carries out the instruction of the RG command and adjusts the maximum transmission

power accordingly even though T2 has not expired. Thereafter, T2 is reset and the T2

timer is re-initiated. This process of adjusting the adjusted maximum transmission

power can be repeated if the non-serving cell continues to transmit the RG commands

and satisfies the first specified condition. However, if T2 is uninterrupted by the non-

serving cell, then the MS can resume normal operation after the expiration of T2 such

as executing the instruction to increase the maximum transmission power of the

serving BS.

Similarly, in Figure 7, which refers to Figure 5, after the MS adjusted the

maximum transmission power, the MS receives a specified number (N4) of 'DOWN'

commands from the non-serving cell during T2, thus again satisfying the second

specified condition. Therefore, when the second specified condition is satisfied, the

MS carries out the instruction of the RG command and adjusts the maximum

transmission power accordingly even though T2 has not expired. Thereafter, T2 is reset

and the T2 timer is re-initiated. However, if T2 is uninterrupted by the non-serving cell,

then the MS can resume normal operation after the expiration of T2 such as executing

the instruction to increase the maximum transmission power of the serving BS. As

mentioned above, the MS can use either the transmission power or the transmission

rate.

In the examples of above with respect to numbers of RG commands, namely,

N1-N4, the values of Nl, N2, N3, and N4 can be same or different. That is, for example, since Figures 6 and 7 occur after the first and the second specified condition

are satisfied, respectively, Nl and N3 can be same N2 and N4 can be same. At the

same time, these values can be different and independent of each other.

Moreover, any combination of the examples or embodiments (Figures 4-7) of

above can be executed. For example, after the maximum transmission power is

decreased upon satisfying the first specified condition, if the MS receives N4 number

of RG commands (e.g., 'DOWN' command) from the non-serving cell during T2, the

maximum transmission power is decreased and the T2 timer is reset.

Alternatively, to maintain the adjusted maximum transmission power during

T_keep or T2, as explained in Figure 3, the non-serving cell can transmit the RG

command the specified period of time, as shown in Figure 8. Here, the RG command

could include an instruction to maintain the maximum transmission power (i.e.,

'KEEP' command). The specified period of time can vary based on the 'KEEP'

command. In other words, the MS can maintain the maximum transmission power as

long as the 'KEEP' command is received. Therefore, here, a number of 'KEEP'

commands received by the MS from the non-serving cell determines the duration in

which the maximum transmission is maintained.

If a maximum transmission power of the MS is determined according to the

method discussed above, the MS determines the actual transmission power by which to

transmit the data packet via an Enhanced uplink Dedicated Channel (E-DCH) within

the allowed transmission range, not exceeding the determined transmission power. Furthermore, the MS can receive the scheduling command from the serving BS when

the serving BS is in the RG command transmission mode or non-transmission mode.

It will be apparent to those skilled in the art that various modifications and

variations can be made in the present invention without departing from the spirit or

scope of the inventions. Thus, it is intended that the present invention covers the

modifications and variations of this invention provided they come within the scope of

the appended claims and their equivalents.

Claims

I oClaims

1. A method of scheduling uplink channel of a mobile station (MS) that is

in soft handover in a wireless mobile communication system, the method comprising:

receiving a plurality of scheduling commands from a non-serving cell;

determining whether a specified condition is satisfied from the received

scheduling commands; and

adjusting a maximum transmission power when the specified condition

is satisfied.

2. The method of claim 1, wherein the scheduling command is a relative

grant (RG) command.

3. The method of claim 2, wherein the RG command is an instruction to

decrease a maximum transmission power.

4. The method of claim 2, wherein the RG command is an instruction to

maintain a current maximum transmission power.

5. The method of claim 4, wherein the RG command is in a form of a

discontinuous transmission (DTX), the DTX does not transmit any signals.

6. The method of claim 2, wherein the RG command is an instruction to

maintain the adjusted maximum transmission power for a specified time period.

7. The method of claim 6, wherein the RG command is in a form of a

discontinuous transmission (DTX), the DTX does not transmit any signals.

8. The method of claim 2, wherein the specified condition is receiving

consecutively a first specified number of RG commands, each containing a same

instruction, by the MS.

9. The method of claim 2, wherein the specified condition is receiving a

specified number of RG commands, each containing a same instruction, during a first

specified time period by the MS.

10. The method of claim 2, wherein the specified condition is at least one of

receiving consecutively a first specified number of RG commands by the MS and receiving a second specified number of scheduling commands during a first specified

time period by the MS, wherein each RG command contains a same instruction.

11. The method of claim 10, wherein values of the first specified number of

RG commands and the second specified number of RG commands are same.

12. The method of claim 10, wherein values of the first specified number of

RG commands and the second specified number of RG commands are different.

13. The method of claim 1, wherein the non-serving cell is a cell from

which no scheduling command is transmitted.

14. The method of claim 1, wherein the adjusted maximum transmission

power is maintained for a predetermined time period.

15. The method of claim 14, further comprising:

receiving a plurality of scheduling commands from a non-serving cell

during the predetermined time period; determining whether a specified condition is satisfied from the received

scheduling commands;

adjusting a maximum transmission power when the specified condition

is satisfied; and

resetting the predetermined time period after adjusting the maximum

transmission power.

16. The method of claim 15, wherein the scheduling command is a relative

grant (RG) command which includes an instruction to decrease a maximum

transmission power or an instruction to maintain a current maximum transmission

power.

17. A method of scheduling uplink channel of a mobile station (MS) that is

receiving a plurality of scheduling commands from a non-serving cell

by the MS, wherein the scheduling command is a relative grant (RG) command;

determining whether at least one of a first specified condition and a

second specified condition is satisfied from the received plurality of scheduling

commands, wherein the first specified condition is receiving a first specified number of RG commands, each containing the same instruction, consecutively, and the second

specified condition is receiving a second specified number of RG commands, each

containing the same instruction, during a specified period of time; and

adjusting the maximum transmission power when any one of the first

specified condition and the second specified condition is satisfied.

18. The method of claim 17, wherein the RG command includes an

instruction to decrease the maximum transmission power.

19. The method of claim 17, wherein the RG command includes an

instruction to maintain the maximum transmission power.

20. The method of claim 17, wherein the adjusted maximum transmission

power is maintained for a predetermined time period.

21. The method of claim 20, further comprising:

receiving a plurality of RG commands from the non-serving cell during

the predetermined time period by the MS; determining whether at least one of a third specified condition and a

fourth specified condition is satisfied from the received plurality of RG commands,

wherein the third specified condition is receiving a third specified number of RG

commands, each containing the same instruction, consecutively, and the fourth

specified condition is receiving a fourth specified number of RG commands, each

containing the same instruction, during the predetemined time period;

adjusting the maximum transmission power when at least one of the

third specified condition and the fourth specified condition is satisfied; and

resetting the predetermined time period after the RG command is

executed.

22. The method of claim 21, wherein the adjustment of the maximum

transmission power includes increasing or decreasing the maximum transmission

power.

23. The method of claim 21, wherein the first specified number of RG

commands is same as at least one of the second specified number of RG commands,

third specified number of RG commands, and the fourth specified number of RG

commands.

24. The method of claim 21, wherein the second specified number of RG

commands is same as at least one of the third specified number of RG commands and

the fourth specified number of RG commands.

25. The method of claim 21, wherein the third specified number of RG

commands is same as the fourth specified number of RG commands.

26. The method of claim 21, wherein the first specified number of RG

commands is different from at least one of the second specified number of RG

commands, third specified number of RG commands, and the fourth specified number

of RG commands.

27. The method of claim 21, wherein the second specified number of RG

commands is different from at least one of the third specified number of RG

commands and the fourth specified number of RG commands.

28. The method of claim 21, wherein the third specified number of RG

commands is different than the fourth specified number of RG commands.

29. The method of claim 17, wherein the RG command includes a sub¬

command which instructs the MS to maintain the adjusted maximum transmission

power for a predetermined time period.

30. A method of scheduling uplink channel of a mobile station (MS) that is

receiving a plurality of relative grant (RG) commands from a non-

serving cell;

determining whether a first specified condition is satisfied from the

received RG commands; and

adjusting the maximum transmission power when the first specified

condition is satisfied.

31. The method of claim 30, wherein the first specified condition includes a

first condition and a second condition, the first condition is defined by receiving

consecutively ^ΛN1 ' number of RG commands by the MS, each containing a same

instruction, and the second condition is defined by receiving ^λN2^f number of RG

commands, each containing a same instruction, during ^λTl ' time period by the MS. _n ,.

26

32. The method of claim 30, wherein the RG command is an instruction to

maintain a current maximum transmission power.

33. The method of claim 30, wherein the RG command includes an

instruction to decrease a maximum transmission power.

34. The method of claim 33, wherein the adjusted maximum transmission

power is maintained for ^λT2' time period.

35. The method of claim 34, further comprising:

receiving a plurality of relative grant (RG) commands from a non-

serving cell during ^XT2' time period;

determining whether a second specified condition is satisfied from the

received RG commands;

executing the RG command when the second specified condition is

satisfied; and

resetting a time of ^ΛT2' time period after the RG command is executed.

36. The method of claim 35, wherein the second specified condition

includes a third condition and a fourth condition, the third condition is receiving

consecutively ^ΛN3' number of RG commands, each containing a same instruction,

and the fourth condition is receiving ^ΛN4' number of RG commands, each containing

a same instruction, during ^ΛT2' time period.

37. The method of claim 36, wherein a value of ^XN1 ' is same as at least

one value of ^λN2/ a value of ^ΛN3/ and a value of ^λN4/

38. The method of claim 36, wherein a value of ^ΛN2' is same as at least

one value of ^λN3/ and a value of ^λN4. '

39. The method of claim 36, wherein a value of ^λN3 ' is same as a value of

^ΛN4/

40. The method of claim 36, wherein at least two values of ^λNl/ ^λN2/

^λN3/ and ^ΛN4' are different.

41. The method of claim 32, wherein the RG command includes an

additional instruction to maintain the executed maximum transmission power for ^ΛT2'

time period.