JP2000041280A - Transmission output control method - Google Patents

Abstract

(57) [Summary] [Problem] To avoid frequent transmission output control every time switching is performed in a place where the improvement effect by diversity is small,
Provided is a transmission output control circuit of a transmission power amplifier circuit that performs transmission output control and a transmission output control method that can simplify the control method. SOLUTION: After switching from a communication range using one carrier to a communication range using two carriers, a transmission output is made constant at a maximum transmission output. By making the transmission output constant at the maximum transmission output in this way, it is not necessary to control the transmission output by increasing or decreasing the number of carrier waves. The number of carriers may be two or more. Further, the reference of the transmission output for increasing or decreasing the number of carrier waves may be any transmission output. When the code error rate of the mobile station reaches an upper limit set in advance, a new carrier is allocated, and the code error rate can be improved under the condition of keeping the transmission power lower than the maximum transmission power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission output control method in wireless communication, particularly in mobile communication using a plurality of wireless channels simultaneously.

[0002]

2. Description of the Related Art Conventionally, it has been known that the use of a plurality of wireless channels facilitates realization of reliability of a wireless communication line (channel), high-speed data transmission, and the like. For example, by transmitting the same signal using two carriers, frequency diversity can be achieved, and the code error rate characteristics can be improved with the same signal power as compared with the case where frequency diversity is not performed.

[0003] In a mobile communication system, there is a method of using a plurality of radio channels to enable higher-speed transmission and higher-reliability transmission. Using a plurality of wireless channels in this way has the effect of increasing the frequency utilization efficiency due to diversity. For example, higher-speed transmission becomes possible by using a plurality of carriers without changing the signal bandwidth of an existing mobile communication system.

Further, if the number of radio channels to be used is adjusted according to the magnitude of the propagation loss between the base station and the mobile station,
The subscriber capacity of the entire mobile communication system can be increased.

[0005] If the number of radio channels to be used is increased, generally less signal power is required to obtain the same bit error rate. Therefore, if the signal power is controlled to a predetermined value in transmission output control, less transmission power is required. As described above, since the transmission output of the transmitting station can be reduced, co-channel interference can be further reduced.

FIG. 1 shows a service area of a conventional mobile communication method using a plurality of radio channels.

As shown in FIG. 1, mobile communication is performed between a base station 100 and a mobile station 110 using up to two carriers. An area close to the base station 100 is serviced as a service area 120 using one carrier, and the base station 1
An area farther than 00 is provided as a service area 130 using two carriers.

FIG. 2 shows the transmission output of mobile station 110 in FIG. 1 on the vertical axis, and shows the distance between base station 100 and mobile station 110 on the horizontal axis.

In FIG. 2, mobile station 110 uses the maximum transmission power as a condition for increasing or decreasing the number of carriers. Mobile station 11
When the distance between 0 and the base station 100 is short, wireless communication is performed using one carrier, as indicated by one carrier 220. As the distance between mobile station 110 and base station 100 increases, the transmission output of mobile station 110 increases to maintain the required channel quality. When the maximum transmission power 240 is reached at the point A205, the mobile station 110 requests the base station 100 to use two carriers. In response to this request, one carrier is newly assigned to the mobile station 110 from the base station controller. 2 carriers 23 from point B 215
As shown by 0, wireless communication is newly started on two carriers. Thereafter, the transmission power of the mobile station 110 is controlled up to the transmission power at which the required channel quality is achieved, for example, the maximum transmission power 240 at the point C225. With this series of steps, mobile communication has been performed using a plurality of carriers.

[0010]

As shown in FIG. 1 and FIG. 2, a service at a cell edge, for example, by two carriers is used.
At the end of the area 130, wireless communication can be performed with less signal power by using a plurality of wireless channels than before.

However, in the above-described method using a plurality of radio channels, the frequency of switching the number of radio channels increases as the distance from the base station increases, and when the transmission output is controlled each time the radio channels are switched, the radio channels are switched. In the vicinity, there is a problem that the transmission output needs to be frequently controlled.

[0012] The effect of improving the required signal-to-noise power ratio due to the above-mentioned diversity also decreases with an increase in the number of branches to be combined. Therefore, frequent transmission output control in a place where such an improvement effect is small is not very meaningful. Not really.

[0013] Therefore, an object of the present invention is to solve the above-mentioned problem, and frequent transmission output control is not performed every time switching is performed, as described above, where there is little improvement effect by diversity. A transmission output control method is provided.

It is a further object of the present invention to provide a transmission output control circuit of a radio circuit, particularly a transmission power amplifier circuit for performing transmission output control, and a transmission output control method capable of simplifying the control method.

[0015]

According to the first aspect of the present invention,
In a transmission power control method for a transmission station in a mobile radio communication system having a transmission station and a reception station performing radio communication with the transmission station, the transmission station may transmit the transmission power to a predetermined transmission power. Newly setting N (N is an integer of 1 or more) wireless communication channels as a wireless communication channel between the wireless communication channel and the receiving station;
Maintaining the transmission output of the transmitting station constant using the number of wireless communication channels.

According to a second aspect of the present invention, there is provided a transmission output control method for a transmitting station in a mobile radio communication system having a transmitting station and a receiving station performing wireless communication with the transmitting station. When the code error rate during the period becomes equal to or less than a predetermined value, N (N is an integer of 1 or more) wireless communication channels are newly set as wireless communication channels between the transmitting station and the receiving station. A transmission power control method comprising: a step of: maintaining a transmission power of the transmitting station constant using the set N radio channels.

According to a third aspect of the present invention, in the first aspect, the predetermined transmission output is a maximum transmission output of the transmission station, and the step of keeping the transmission output of the transmission station constant is a step of transmitting the transmission output of the transmission station. Can be kept at the maximum transmission output.

According to a fourth aspect of the present invention, in the second aspect, the code error rate may be a bit error rate.

The invention according to claim 5 provides the invention according to claims 1 to 4
In any case, the wireless communication channel can be a carrier.

The invention according to claim 6 is the invention according to claims 1 to 5
In any case, the transmitting station may be a mobile station and the receiving station may be a base station.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 shows an embodiment of the transmission output control method according to the present invention.

In FIG. 3, the cellular model complies with FIG. 1, and similarly to FIG. 1, the transmission output of mobile station 110 is shown on the vertical axis, and the distance between base station 100 and mobile station 110 is shown on the horizontal axis.

The difference between FIG. 3 and FIG. 2 of the conventional example is that one carrier 320 corresponds to point A305 (corresponding to point A205).
Is switched from the communication range 350 by the communication range 360 to the communication range 360 by the two carriers 330, the transmission output is constant at the maximum transmission output 340 up to a point C325 (corresponding to the point C225). By making the transmission output constant at the maximum transmission output 340 in this way, it is not necessary to control the transmission output by increasing or decreasing the number of carriers. That is, it is not necessary to perform frequent transmission output control every time the number of carriers is switched. Therefore, the transmission output control circuit of the transmission power amplifier circuit that performs transmission output control and the control method thereof can be simplified.

In the above-described embodiment, the number of carriers is two, but this is merely an example, and it goes without saying that the number of carriers may be two or more. Further, in the above-described embodiment, the reference of the transmission output for increasing / decreasing the number of carriers is set to the maximum transmission output 340, but this is for illustration only, and the reference for the transmission output for increasing / decreasing the number of carriers is arbitrary transmission output It may be.

FIG. 4 shows an embodiment of the transmission output control method according to the present invention.

FIG. 5 shows the bit error rate on the vertical axis and the distance between the base station and the mobile station on the horizontal axis in the case of FIG. The code error rate on the vertical axis decreases as going downward.
A point A410 common to FIGS. 4 and 5 indicates that the distance between the base station and the mobile station is equal.

As shown in FIG. 5, an upper limit 500 of the bit error rate that defines the required channel quality is set. For example, in the voice of digital mobile communication, the bit error rate is 1
%, This 1% becomes the upper limit 500 of the bit error rate. However, the bit error rate can be arbitrarily set as needed. It goes without saying that the code error rate may be not only the bit error rate described above but also a symbol error rate.

As the mobile station using one carrier 520 moves away from the base station, the bit error rate deteriorates. With this deterioration, as shown in FIG. 4, the transmission output monotonically increases in order to secure the required line quality. One carrier 520
When the code error rate of the mobile station reaches the preset upper limit value 500 at point A410 during communication using, the mobile station requests the base station controller to set a new carrier.
In response to this request, the base station controller allocates another carrier. As a result, the two carriers 53
0 can be used for wireless communication with the base station. By using the two carriers 530 in the mobile station, the code error rate can be improved under the condition that the transmission power 400 is kept lower than the maximum transmission power 440, as shown in FIG. 4, due to the frequency diversity effect. In this manner, by maintaining the transmission output at a constant transmission output 400 by increasing the number of carriers, the code error rate can be reduced to a predetermined value or less without performing control such as transmission output control.

In the above embodiment, the description has been made using the carrier wave as the radio channel. However, the radio channel is not limited to these, and other radio channels such as a TDMA time slot and a CDMA spreading code may be used. It may be.

In the above embodiment, the description has been made using the bit error rate as the code error rate. However, the code error rate is not limited to these, and may be a symbol error rate or the like.

As described above, advanced transmission power control at the area edge is not required, the transmission power control circuits in the transmission power amplifiers of the mobile station and the base station can be simplified, and the transmission power control method is compatible with the existing transmission power control method. You can keep the nature.

[0033]

As described above, according to the transmission output control method of the present invention, the transmission output is kept constant after the switching of the number of carriers at a place where the improvement effect by the diversity is small. It is possible to provide a transmission output control method that does not require frequent transmission output control. Further, it is possible to provide a transmission output control circuit of a wireless circuit, particularly a transmission power amplification circuit that performs transmission output control, and a transmission output control method that can simplify the control method.

[Brief description of the drawings]

FIG. 1 is a diagram showing a service area of a conventional mobile communication method using a plurality of wireless channels.

FIG. 2 shows the transmission output of the mobile station in FIG. 1 on the vertical axis,
FIG. 3 is a diagram illustrating a distance between a base station and a mobile station on a horizontal axis.

FIG. 3 is a diagram showing one embodiment of a transmission output control method of the present invention.

FIG. 4 is a diagram showing one embodiment of a transmission output control method of the present invention.

FIG. 5 is a diagram illustrating a bit error rate on a vertical axis and a distance between a base station and a mobile station on a horizontal axis in the embodiment of FIG. 4;

[Explanation of symbols]

 Reference Signs List 100 base station 110 mobile station 120, 350 Service area with one carrier 130, 360 Service area with two carriers 220, 320, 520 Single carrier 230, 330, 530 Two carriers 240, 340, 440 Maximum transmission power 400 Code error rate Transmission power to obtain the upper limit of 500 Upper limit of the bit error rate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K060 BB00 CC04 CC12 CC19 DD04 FF09 HH06 PP03 5K067 AA21 CC04 CC10 CC24 EE02 EE10 EE63 EE65 GG08 HH22 LL11

Claims (6)

[Claims] 1. A transmission output control method for a transmission station in a mobile radio communication system having a transmission station and a reception station performing radio communication with the transmission station, wherein the transmission output of the transmission station reaches a predetermined transmission output. If
Newly setting N (N is an integer of 1 or more) wireless communication channels as a wireless communication channel between the transmitting station and the receiving station, and using the set N wireless communication channels Maintaining the transmission output of the transmitting station constant. 2. A transmission power control method for a transmitting station in a mobile radio communication system having a transmitting station and a receiving station performing wireless communication with the transmitting station, comprising: a code error rate between the transmitting station and the receiving station. If N is equal to or less than a predetermined value, newly setting N (N is an integer of 1 or more) wireless communication channels as a wireless communication channel between the transmitting station and the receiving station; Maintaining the transmission output of the transmitting station constant using the N radio channels. 3. The transmission output control method according to claim 1, wherein the predetermined transmission output is a maximum transmission output of the transmission station, and the step of keeping the transmission output of the transmission station constant includes the transmission output of the transmission station. A transmission output control method characterized by maintaining a maximum transmission output. 4. The transmission power control method according to claim 2, wherein said code error rate is a bit error rate. 5. The transmission power control method according to claim 1, wherein said wireless communication channel is a carrier wave. 6. The transmission power control method according to claim 1, wherein said transmission station is a mobile station, and said reception station is a base station.