JP2002171221A - Transmission power controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a transmission power from being immediately controlled so as to be increased or decreased when the reception quantity of mobile radio equipment is deteriorated in a transmission power controller for allowing the mobile radio equipment to control the increase or decrease of the transmission power according to a control instruction from a radio ground station when the mobile radio equipment is notified of the control instruction of the transmission power from the radio base station. SOLUTION: This mobile radio equipment is provided with a transmission power control judging means for judging the reception quality of the mobile radio equipment from a radio base station, and for setting the number of times how many the same kinds of control instructions should be repeatedly accepted based on the judged result, and for allowing the mobile radio equipment to control the increase or decrease of a transmission power when the mobile radio equipment is notified of the control instructions for the number of times how many the control instructions should be repeatedly accepted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control device for, when data is transmitted from a mobile station to a base station, determining the control content instructed by the base station and increasing or decreasing the transmission power to the base station. It is about. In particular, it is suitable for a mobile communication system using a closed loop using transmission power control bits (TPC bits).

[0002]

2. Description of the Related Art Conventionally, mobile communication systems such as C
In a cellular (small zone configuration) mobile communication system using DMA (Code Division Multiple Access), increase / decrease control of transmission power is performed in response to a change in communication environment as shown in FIG. That is, communication radio waves are emitted from the radio base stations 110a, 110b,... Into the respective cellular areas, and the communication radio waves are spread while being hindered by the high-rise building groups 120a, 120b,. For this reason, from each point in the corresponding cellular phone, communication with the radio base station 110a is performed by radio waves 140a, 140b, 140c,... Via multipaths (a plurality of propagation paths), so that the electric field strength of the received radio waves is frequent. I have to fluctuate.

[0003] Therefore, the mobile radio apparatus 130 constantly moving at these points performs power control in a closed loop with the radio base station on the transmission signal during communication so that the transmission quality can be obtained so as to obtain the optimum communication quality. Regulating power. For example, there is a method of controlling a transmission power by paying attention to a traffic channel during communication and receiving an instruction from the radio base station 110a received on the channel. .. Are connected to a switching network of the radio base station control device 110 or the like.

A conventional mobile radio apparatus 130 shown in FIG.
The radio frequency unit 131 performs RAKE combining while transmitting and receiving the radio waves 140a, 140b, 140c,.
Then, the reception demodulation unit 132 introduces the received signal of the traffic channel as its RAKE output and performs demodulation. Then, the transmission power control information cutout unit 133 separates the user data output S101 from the demodulated digital signal and sends it to the communication processing unit 134. In the communication processing unit 134, the user data output S101 is used for image and voice synthesis and various arithmetic processes, and as a result of these processes, the user data input S102 is generated and the variable gain transmission amplifier 13
Introduce to 5. The variable gain transmission amplifier 135 amplifies transmission power based on an appropriate amplification gain described later,
The transmission signal is organized by the modulation transmission unit 136 and transmitted to the radio base station 110a via the radio frequency unit 131.

Further, a transmission power control information extracting section 133
From the transmission power control bit S103 after RAKE combining.
Are separated and cut out and sent to the amplification gain setting control processing unit 137 for each time slot (slot) that is the minimum transmission unit for each communication frequency. The amplification gain setting control processing unit 14 searches the amplification gain step value storage unit 138 according to the transmission power control bit S103. Appropriate step value S104 for increase / decrease control as a search result
And the variable gain transmission amplifier 135 is set to the step value S
Increase / decrease is controlled by an amplification gain S105 corresponding to 104. The baseband unit 139 includes the reception demodulation unit 132, the transmission power control information extraction unit 133, the variable gain transmission amplifier 135, the modulation transmission unit 136, the amplification gain setting control processing unit 137, and the amplification gain step value storage unit 138. . In addition to this, as to the transmission power control of the mobile radio apparatus 130, an example in which interference with another mobile radio apparatus is prevented by open-loop control disclosed in Japanese Patent Application Laid-Open No. 8-32514 is used.

The transmission power control bit S103 is composed of one bit attached to the user data S101 as shown in FIG. 4, and is a bit for simply instructing the transmission power to be increased or decreased for each slot. As a typical control procedure at this time, there is a procedure of comparing the reception level and the reception quality of the corresponding traffic channel with a preset reference value or target value. According to this, when the reception quality or the like is high, the mobile radio device 1
In this case, the transmission power is decreased, and if the transmission power is low, the transmission power is increased so that the required appropriate power is obtained. Thus, the transmission power control bit S1
03 controls the transmission power of the mobile radio apparatus 130 for each slot from the radio base station 110a to maintain required reception quality. Such a radio base station 110a
For example, Japanese Patent Laid-Open No. 9-2753
As disclosed in JP-A-73-73, an example of optimizing by judging the increase / decrease tendency based on the reception history may be used.

[0007]

However, the control procedure for maintaining the reception quality at the radio base station 110a according to the conventional example described above does not sufficiently cope with the fading phenomenon caused by the multipath shown in FIG. Absent. Actually, the multipaths 140a, 140b, 1 are transmitted from the radio base station 110a.
When a plurality of communication radio waves having different phases arrive through the channels 40c... And the mobile radio apparatus 130 moves within the area, a sudden fading may generally occur due to a change in a surrounding propagation path or the like. For this reason, an error occurs not only in the user data S101 inserted in the corresponding slot but also in the transmission power control bit S103 itself, which may cause an erroneous increase or decrease in transmission power. Further, in the state where the propagation environment of the communication radio wave is poor, if the transmission power control bit S103 is erroneously determined even though it is desired to increase the transmission power, the transmission power is reduced. However, there has been a serious problem that communication quality is increasingly deteriorated.

[0008] This is because the precondition of the transmission power control is indicated by the transmission power control bit, but the reliability of the underlying transmission power control bit is not strictly guaranteed. On the other hand, in the conventional procedure, when the error can be estimated by predicting the certainty of the transmission power control bit,
A method of preventing further deterioration of communication quality due to a determination error of the transmission power control bit has been taken by a configuration not simply adopting the control bit.

For example, in the transmission power control bit S103,
Parity information for estimating the bit error is added or the signal power to noise power ratio (SN
The ratio is measured for each slot, and it is determined whether to perform transmission power control while estimating the possibility of a bit error in the transmission power control bit S103. However, in order to realize these means, it is necessary to provide a parity information generation circuit and an additional circuit in the radio base station 110a, and to add a hardware for confirmation such as a parity information separation circuit and a collation circuit to the mobile radio apparatus 130. There is. In addition, the information amount of the user data output S101, which is the main information in the corresponding slot, is reduced by the parity bit, and high-speed hardware for measuring and calculating the above-described SN ratio for each slot is required. This creates new problems.

As described above, when an information transmission error occurs when the radio propagation environment suddenly and temporarily deteriorates, the mobile radio device erroneously issues a transmission power increase instruction from the radio ground station as a decrease instruction. In some cases, it may be determined, but even in such a case, it is required that the transmission power is not reduced and the communication quality is not further deteriorated.

[0011]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a method for transmitting a transmission power control instruction from a radio base station to a mobile radio apparatus, the mobile radio apparatus transmits the transmission power control instruction. In the transmission power control device that controls the increase or decrease of power, the mobile radio device determines the reception quality from the radio base station, and sets the number of times that the same type of control instruction should be repeatedly received based on the determination result. The mobile radio device has a transmission power control determining means for controlling to increase or decrease the transmission power of the mobile radio device when a control instruction for the number of times to be received is notified.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) Embodiment (A-1) Configuration of Embodiment Hereinafter, an example of an embodiment in which a transmission power control apparatus according to the present invention is applied to a CDMA mobile communication system will be described in detail with reference to the drawings. I do.

The CDMA mobile communication system in this case is as follows:
As with the system shown in FIG. 2 described above, a plurality of radio base stations 110a, 110a, 1
10b... Groups and their respective wireless base stations 110a, 110
10b, and one or a plurality of mobile wireless devices 130 moving in a small zone area under the jurisdiction of 10b.

The transmission power control apparatus for CDMA mobile communication of this embodiment is applied to the baseband section of each mobile radio apparatus, and its function can be shown in the block diagram of FIG. In FIG. 1, the baseband unit 139a includes
The above-mentioned reception demodulation section 132 of the received signal, transmission power control information cutout section 13 for separating user data output S101
3, a transmission power control determining unit 70 described later, a variable gain transmission amplifier 135 for amplifying the user data input S102 as a transmission signal, and a modulation transmission unit 136.

The transmission power control determination means 70 includes a control information storage and recording unit 71 for the transmission power control bit S103, an amplification gain step value storage unit 72 for transmission power control, and a recording of the control information storage and recording unit 71. A reception control information determination processing unit 73 that searches the step value of the amplification gain step value storage unit 72 while determining the necessity of the transmission power control according to the content, and an amplification gain that sets increase / decrease control based on the determination result based on the step value. A setting control processing section 74, a quality state collection interface section 75 for collecting reception quality in the above-described radio frequency section 131, a quality state for storing reception quality state information and causing the reception control information determination processing section 73 to start a determination process. An information storage unit 76 is provided.

The control information storage and recording unit 71 transmits the transmission power control bit S10 from the transmission power control information extracting unit 133.
3 is a memory capable of accumulating 3 as a predetermined number of bit strings over time and simultaneously reading and erasing the stored bit strings. Also, the transmission power control bit S103
Has a power reduction instruction bit continuous counter that counts when is a reduction instruction value, and its reference value register.

The amplification gain step value storage section 72 is a memory in which a step value S72, which is a control unit necessary for the control for increasing and decreasing the transmission power, is stored in advance.

The reception control information determination processing section 73 reads the bit string and the count value of the transmission power control bit S103 from the control information storage and recording section 162 to obtain the control information S71, and determines the transmission power increase / decrease instruction S73 based on these. . Further, the processing unit reads the step value S72 of the increase / decrease control from the amplification gain step value storage unit 73 to determine the increase / decrease value, forms the increase / decrease signal S73 together with the increase / decrease instruction, and sends it to the amplification gain setting control processing unit 74. The reception control information determination processing unit 73 determines the degree of instability (m) of the reception quality as the number of consecutive bits (N
1) a continuous bit number correspondence table for conversion, a stability reference value and a minimum threshold value for determining reception quality,
Each register of the reference value of the reception level at the finger is provided. The number of consecutive bits (N1) is used to determine the degree of request for reduction in transmission power.

As shown in FIG. 5, the consecutive bit number correspondence table stores integer values obtained by previously dividing the instability (m) of the reception quality into two or more levels corresponding to the continuous bit number (N). They are arranged to estimate that the numerical value “0” is most stable, and that the instability of the reception quality increases as the numerical value increases. For example, since the instability (m) = 0 indicates a high stability state, it is estimated that a received bit error hardly occurs, and the number of consecutive bits (N1)
= 1. In this case, the transmission power control for each slot may be performed as in the conventional example without using the number of consecutive bits (N1). In addition, the maximum value of instability (m) (mma
x) is converted into a continuous number (Nnop) for ignoring the transmission power control bit S103.

The amplification gain setting control processing unit 74 sets the amplification gain signal S74 of the transmission power based on the increase / decrease signal S73 introduced from the reception control information judgment processing unit 73, and sets the amplification gain signal S74 of the variable gain transmission amplifier 135 as a target value. This is a processing unit that controls the gain.

The quality state collection interface unit 75
The quality state signal S of the received radio wave measured by the radio frequency unit 131
This is an interface that collects 131, performs RAKE synthesis, and updates the storage content of the quality status information storage unit 76 while collecting the quality status information S75 at predetermined intervals. In this case, the predetermined period is preferably, for example, a period of about 1 second.
It is sufficient that the period is sufficiently longer than the time interval for extracting 103.

The quality status information storage unit 76 introduces and stores the quality status information S75, and notifies the reception control information determination processing unit 73 as needed while constantly updating the quality status information S76 to the latest quality status information S76. .

With the above configuration, the weight of the transmission power control bit is changed by using the quality state signal S131 of the received radio wave, the transmission power is gently reduced, and the transmission power control bit S103 is independently bit-separated. Even if an error occurs, an optimal number of consecutive bits is set according to the change in the propagation environment of the radio wave, and the transmission power control bits S
As long as 103 does not continue, erroneous control of erroneously reducing the transmission power is not performed.

(A-2) Operation of the embodiment The transmission / reception of the radio wave is performed by the radio frequency unit 131, demodulated into a digital signal by the reception demodulation unit 132, and the transmission power control bit S 103 is transmitted by the transmission power control information extracting unit 133. The fact that the user data output S101 is obtained while being separated and the fact that the user data input S102 is variably amplified by the variable gain transmission amplifier 135 and modulated by the modulation transmission unit 136 to the transmission frequency are the same as those of the conventional CDMA described above. Since the configuration is the same as that of the transmission power control device for mobile communication, detailed description is omitted.

Therefore, in the baseband section 139a,
A description will be given with reference to FIG. 6 assuming that the transmission power control bit S103 is separated and cut out from the demodulated received radio wave and stored in the control information storage recording unit 71. As a precondition, the following power control determination processing is executed on the assumption that the storage content of the quality state information storage unit 76 is constantly updated to the latest quality state information S76. First, the reception control information determination processing unit 73 periodically reads out the latest quality state information S76 (S101), and determines whether or not the update has been performed since the time of the previous readout (S10).
2). The periodic reading (S101) and the update determination (S102) are repeatedly executed until the update is actually performed.

When the update is performed, a reception quality determination process (S103) for determining the degree of instability (m) of the reception quality based on the latest quality state information S76 is executed, and the transmission power is determined according to the continuous bit number correspondence table described above. The number of consecutive bits (N1) for determining the degree of the decrease request is determined (S104). And the determined number of consecutive bits (N1)
, The transmission power is controlled (S105).

Next, an example of the reception quality judgment processing (S101) will be described with reference to FIG.

As a premise, the quality state collection interface unit 131 evaluates the signal strength of the received radio wave with respect to the noise level in advance and, for example, considers the existence of another mobile radio device in the same small zone and desires a desired wave to an interference wave. The power ratio (SIR value) is determined as a reception quality determination factor.
Further, from a correspondence detection unit (not shown), finger path (finger) information assigned to the received radio wave is obtained, and the quality state information S7 is collected while periodically collecting them.
5, the state of the reception quality is estimated. As the finger information at this time, the number of assigned fingers and the reception level of each finger may be used.

First, a signal strength margin check is prepared for the noise level based on the SIR value of the latest quality state information S76 (S201), and the SIR value is compared with a predetermined stability reference value (SIRstd) (S201). S202). If the SIR value is smaller than the stable reference value (SIRstd), the comparison with the lowest threshold value (SIRmin) is further performed (S208). Note that the stability reference value (SIRstd) and the minimum threshold value (SIRmin) are set in advance in each register of the reception control information determination processing unit 73.

If the SIR value is smaller than the minimum threshold value (SIRmin), the degree of instability (m) is increased to a predetermined maximum value (mma).
x) (S209). As described above, when the margin of the SIR value is extremely low, the transmission power control bit S
Since the probability of occurrence of 103 bit errors frequently increases,
Without determining the transmission power control bit S103, the transmission power is maintained at the current value.

However, when the SIR value is the lowest threshold value (SIR
If it is higher than min), there is a possibility that some bit error will occur, so the instability (m) is determined according to the small SIR value (S207).

In the above-described determination processing S202,
If a sufficient margin can be expected because the SIR value is equal to or higher than the stability reference value (SIRstd), preparation processing for confirming the reception level of each assigned finger and confirming the number of fingers is performed (S203).

Subsequently, the reception level of each finger is compared with a reference value (Efin), and it is confirmed whether or not there is a finger number (N2) having a reception level equal to or higher than the reference value (Efin) (S204). . The reference value (Efi
n) is a reception level at which a margin for obtaining sufficient reception quality alone can be expected.

Then, the number of fingers (N
It is determined whether or not 2) is one or more (S205). If there is even one, it is estimated that the reception quality can be stabilized, and the degree of instability (m) is set to 0 (S206). Also, if there is no one, it is estimated that a bit error may occur and the SIR
The instability (m) is determined according to the small value (S20).
7).

Generally, in the small zone where the mobile radio apparatus 130 is currently located, a sudden change occurs in the propagation environment of the received radio wave due to the relative positional relationship with the building in the area, the movement of the object around the propagation path, and the like. There are cases. In such a case, by the above procedure, the margin of the signal reception strength with respect to the noise floor is obtained.By evaluating each margin stepwise, the dynamic range that can follow the change or the reception level above a certain level It can be determined whether or not it has a stable finger.

An example of the transmission power control process (S105) will be described with reference to FIG.

As a premise, the control information accumulation recording unit 71 stores the transmission power control bits S103 group separated and accumulated from the received signal, the count value of the accumulated bit string, and the like according to the instruction of the reception control information determination processing unit 73. The data is transferred by reading as needed.

First, the reception control information determination processing section sequentially reads out the transmission power control bits S103 (S30).
1) It is determined whether the bit value indicates an increase instruction value or a decrease instruction value (S302). And if it is a decrease instruction value,
The count value (k) of the above-described power reduction instruction bit continuation counter is incremented by a numerical value “1” and stored in the control information accumulation recording unit 71 (S303). Therefore, the count value (k) is the continuous number of the transmission power control bits S103 indicating the decrease instruction value.

Subsequently, the incremented count value (k) is compared with the aforementioned number of consecutive bits (N1) (S304), and the count value (k) is changed to the number of consecutive bits (N).
If 1) has not been reached, the process returns to the 1-bit readout process of the transmission power control bit (S301) to repeatedly monitor whether or not the decrease instruction value is continuous. Also, the number of consecutive bits (N1)
Is reached, the count value (k) is cleared to 0 (S305).

Then, from the amplification gain step value storage section 72, the step value S7 for controlling the increase or decrease of the transmission power is determined.
2 is read (S306), and the increase / decrease value of the amplification gain (S73) corresponding to the step value S72 is set in the amplification gain setting control processing unit 74 (S307).

Further, the above-described determination processing of the decrease instruction (S3)
In 02), if the transmission power control bit S103 is the increase instruction value, the count value (k) is immediately cleared to 0 (S308) because there is no risk of decrease control, and the power increase / decrease step read processing (S306) is continued. An amplification gain increase / decrease value setting process (S307) is executed.

In this embodiment, an example has been described in which the power reduction instruction bit continuation counter counts the number of consecutive transmission power control bits S103. However, the present invention is not limited to this. Bit S1
It is also possible to use a counter for measuring the number of times 03 can be repeatedly obtained and other frequencies. In this case, a stage in which the reception quality in the mobile radio apparatus tends to deteriorate can be grasped at an early stage, and the reduction control of the transmission power can be avoided in advance.

Further, the present invention is applied to a mobile radio apparatus of a CDMA modulation / demodulation system, but if it is desired to deal with a so-called near-far problem, the above-mentioned radio frequency section, reception demodulation section and modulation / transmission section are replaced by FDMA, TDMA, It may be applied in combination with other modulation and demodulation methods. For the transmission power from the radio base station, besides mobile phones and PHS,
The present invention may be applied to a car phone, a train phone, a ship radio, and a satellite communication with a high-speed processing function.

[0044]

As described above, according to the present invention, when an instruction to control transmission power is sent from a radio base station to a mobile radio apparatus, the mobile radio apparatus controls an increase or decrease in transmission power according to the control instruction. In the transmission power control device, the mobile radio device determines the reception quality from the radio base station, sets the number of times to repeatedly receive the same type of control instruction based on the determination result, and controls the number of times to repeatedly receive the same type of control instruction. When the instruction is notified, the mobile radio device has transmission power control determining means for controlling the transmission power of the mobile radio device to increase or decrease, so that the control from the radio base station is generally performed as the propagation environment of the radio wave deteriorates. Even if the instruction itself may be erroneously determined, the transmission power is increased or decreased by the control instruction only when the same type of control instruction is repeated a set number of times. Therefore, even if a decrease control instruction is erroneously determined due to the deterioration of the reception quality, the transmission power is not immediately controlled, so that the previous communication quality with the radio base station can be maintained.

[Brief description of the drawings]

FIG. 1 is a functional block diagram illustrating a configuration example of an embodiment.

FIG. 2 is an explanatory diagram illustrating an example of a CDMA mobile communication system.

FIG. 3 is a functional block diagram illustrating a configuration example of a conventional mobile wireless device.

FIG. 4 is an explanatory diagram showing an example of transmission power control bits attached to user data.

FIG. 5 is an explanatory diagram illustrating a configuration example of a continuous number conversion table according to the embodiment;

FIG. 6 is a flowchart illustrating an example of a characteristic operation (power determination processing) according to the embodiment;

FIG. 7 is a flowchart illustrating an example of reception quality determination processing of a characteristic operation.

FIG. 8 is a flowchart illustrating an example of transmission power control processing of characteristic operation.

[Explanation of symbols]

Reference numeral 70: transmission power control determination means, 71: control information storage and recording unit, 72: amplification gain step value storage unit, 74: amplification gain setting control processing unit, 75: quality information collection interface unit, 76: quality state information storage unit 131 ... radio frequency part,
132: reception demodulation unit, 133: transmission power control information cutout unit, 135: variable gain transmission amplifier, 136 modulation transmission unit, S101: user data output, S102: user data input, S103: transmission power control bit, S131
Quality state signal, S71: control information, S72: step value, S73: increase / decrease value, S75, S76: quality state information

Claims (3)

[Claims] 1. A transmission power control device in which, when a radio base station notifies a mobile radio device of a transmission power control instruction, the control instruction causes the mobile radio device to control increase or decrease of transmission power. Determine the reception quality from the radio base station,
Based on this determination result, the number of times that the same type of control instruction is to be repeatedly received is set, and when the control instruction for the number of times that the same type of control instruction is to be received is notified, transmission power control for increasing or decreasing the transmission power of the mobile radio apparatus A transmission power control device, wherein the determination means is provided in the mobile radio device. 2. The transmission power control judging means for setting the number of times a transmission power control bit should be continuously and repeatedly received from a radio base station.
The transmission power control device according to claim 1. 3. The transmission power control judging means according to claim 1, wherein the ratio of the desired wave to the interference wave power of the received radio wave is reduced, the number of fingers of the assigned locked received radio wave is reduced, and the finger level of the received radio wave is reduced. The transmission power control device according to claim 1 or 2, wherein the number of times of repetition is set with one of the triggers.