JPH10271089A - Cdma radio transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CDMA radio transmission system that detects information relating to transmission quality of an information signal sent from its own station to an opposite station without remarkable loss of a transmission efficiency while keeping reliability of the information. SOLUTION: An error rate measurement section 25 measures an error rate of an inverse spread output in an inverse spread spectrum section 22 and the error rate reflects the quality of an incoming channel from a 2nd radio station 200 to a 1st radio stational 100. A quality information read section 26 reads an error rate of a signal stream sent from the 2nd radio station at a high speed, that is, the error rate of an inverse spread output by the inverse spread spectrum section measured by the 2nd radio station. A 2nd transmission quality display section 20 displays a read value by the quality information read section 26 when the measurement result by the read rate measurement section 25 is not more than a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to code division multiplexing (CDMA) used in mobile communications.
The present invention relates to an ion multiple access (wireless transmission) system. In particular, by detecting how the transmission information of your own station is received by the other station,
The purpose is to select appropriate signal transmission conditions, signal transmission methods, and transmission procedures, and to use the information for failure diagnosis of a transmission system.

[0002]

2. Description of the Related Art Conventionally, a method for knowing the transmission quality of information transmitted by a local station is based on the fact that the transmission quality such as the received power measured by a remote station is comparable to the information transmitted by the local station or the remote station. A method has been used in which data is sent back to the local station at a transmission rate and then evaluated. However, this method can transmit the "information on transmission quality" itself measured at the partner station without greatly degrading the reliability of transmission when returning from the partner station to the own station. When sending back "information about", the transmission time is occupied, which significantly impairs the transmission efficiency of the information to be transmitted.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the "information relating to the transmission quality" of the information signal sent from the own station to the other station should be transmitted. It is an object of the present invention to provide a CDMA wireless transmission system capable of detecting information transmission efficiency without significantly deteriorating the transmission efficiency of the information and in a state where the reliability of the "information about transmission quality" is sufficiently ensured.

[0004] In particular, it is assumed that the transmission path is a multipath transmission path and that it is used in a radio wave propagation environment that involves a severe electric field fluctuation due to fading. It can be used for many purposes, such as controlling the quality and transmission efficiency to an appropriate state, retransmitting information when the transmission quality is poor, or performing a fault diagnosis of the transmission system of the own station. is there.

[0005]

According to the first aspect of the present invention, a first information signal is spread by a first spreading code from a first wireless station to a second wireless station and transmitted. In a CDMA wireless transmission system in which a second information signal is spread from a second wireless station to the first wireless station by a second spreading code and transmitted, the second wireless station receives the first information signal. First means for measuring the transmission quality of the information signal, and adding the transmission quality measured by the first means to the second information signal at a transmission rate higher than the transmission rate of the second information signal; And second means for transmitting the signal after spreading it with the second spreading code, wherein the first wireless station receives the second information signal and receives the transmission quality of the second information signal. And the first means transmitted from the second wireless station. A fourth means for reading the transmission quality measured in the step, and the first radio based on the value read by the fourth means when the transmission quality measured by the third means is equal to or more than a predetermined value. A fifth means for detecting the transmission quality of the first information signal sent from the station to the second wireless station.

Therefore, the transmission quality of the first information signal transmitted from the first wireless station is measured by the first means of the second wireless station, and the measured quality is transmitted to the first wireless station to be transmitted to the fourth means. And can be detected by reading. In addition, since the transmission quality of the first information signal is added back to the second information signal at a higher transmission speed than the transmission speed of the second information signal, the transmission quality of the second information signal is second. The transmission efficiency of the information signal is not significantly impaired. Also, the transmission quality of the second information signal transmitted from the second wireless station is measured,
When the transmission quality is equal to or higher than a predetermined value, it is assumed that the transmission quality of the first information signal is correctly represented.
The influence of the transmission path in the reverse direction can be eliminated, and the detection can be performed in a state where the reliability of the transmission quality of the first information signal is sufficiently ensured.

According to a second aspect of the present invention, in the CDMA wireless transmission system according to the first aspect, the first means determines a transmission quality based on an error rate of a despread output of the received first information signal. , And the third means measures the transmission quality based on the error rate of the despread output of the received second information signal. Therefore, the transmission quality of the first information signal transmitted from the first wireless station and the transmission quality of the second information signal transmitted from the second wireless station can be easily measured.

According to a third aspect of the present invention, in the CDMA wireless transmission system according to the first or second aspect, the fifth means is arranged so that when a measurement result of the third means is equal to or more than a predetermined value. Calculating the average value of the values read by the fourth means. When the average value is low, the transmission quality of the first information signal is increased. When the average value is high, the first value is calculated. And sixth means for controlling the transmission efficiency of the information signal to increase the transmission quality and the transmission efficiency of the first information signal from the first wireless station to the second radio station.
This is adapted to the line quality in the direction of transmission to the wireless station. Therefore, the transmission quality and the transmission efficiency of the first information signal transmitted from the first wireless station can be adapted to the line quality in the direction from the first wireless station to the second wireless station.

According to a fourth aspect of the present invention, in the CDMA wireless transmission system according to any one of the first to third aspects, the measurement result of the third means is not less than a first predetermined value. When the fifth means detects that the value read by the fourth means is equal to or less than a second predetermined value, the first radio station transmits the transmitted first information signal. It is to retransmit to the second wireless station. Therefore, it is possible to cope with a case where the transmission characteristic in the direction of transmission from the first wireless station to the second wireless station is poor.

According to a fifth aspect of the present invention, in the CDMA wireless transmission system according to any one of the first to fourth aspects, the measurement result of the third means is not less than a first predetermined value. When the fifth means detects that the state in which the value read by the fourth means is equal to or less than a second predetermined value has continued for a predetermined time or more, the first wireless station:
The transmission of the first information signal is stopped. Therefore, when the transmission characteristics of the line in the direction from the first wireless station to the second wireless station continue to be poor, frequency resources are not wasted and interference with other stations can be reduced. .

[0011]

FIG. 1 is a block diagram of a first radio station for explaining an embodiment of a CDMA radio transmission system according to the present invention. FIG. 2 is a block diagram of the second wireless station. Although bidirectional CDMA wireless transmission is performed by combining FIG. 1 and FIG. 2, since the figure becomes too large, it is divided into two figures, FIG. 1 and FIG. As an example, the first wireless station 100 is a base station,
It is assumed that the second wireless station 200 is a mobile station. First, the first wireless station 100 sends the first wireless station 200 a first wireless station 200.
The case of the downlink transmitting the information signal of FIG.

In the first radio station 100 shown in FIG.
Is converted by the error correction code conversion unit 1 into a code capable of error correction, and the output X1 of the error correction code conversion unit 1 is spectrum spread by the spectrum spread unit 2. Assuming that the output X2 of the spread spectrum unit 2 is X3, which is the spread spectrum code output from the spread spectrum code generation unit 3, the following equation is satisfied in chip units. Here _{I m + C mn = S mn} , I m is the information bits constituting the output X1 of the error correction code conversion unit 1, C _mn minimum pulse constituting the spread spectrum code X3 (hereinafter, referred to 1 chip) The unit code, S _mn , represents the code of one chip constituting the output X2 of the spread spectrum unit 2. In addition, + represents addition (for example, exclusive OR) of mod2.

The output X2 of the spread spectrum unit 2 is amplified by the power amplification unit 4 and transmitted as a radio wave by the transmission antenna 5. At this time, the power X2 of the output X2 of the spread spectrum unit 2 is power-amplified after passing through a filter or performing band-limited modulation such as PSK modulation. Furthermore, a frequency conversion unit is provided,
The power may be amplified after converting to an appropriate frequency band.

In this example, the error correction code converter 1
Of the frame synchronization signals F ₁ , F ₂ ,
F ₃ ,..., F _P are added, but these are output as they are without performing the process of adding mod 2 to the spread spectrum code X3 in the spread spectrum code generation unit 2.

In the second radio station 200 shown in FIG. 2, when a radio wave is received by the receiving antenna 6 and passes through the front end 7,
The output X7 of the front end 7 is the same as the output X2 of the spread spectrum unit 2 described above. At this time, demodulation is performed when narrow band modulation such as PSK modulation is performed in the power amplification unit 4 in FIG. 1, and when a frequency conversion unit is provided to raise the frequency to an appropriate frequency band, To the baseband band. Further, the frame synchronization signals F ₁ , F
_2, F _3, · · ·, performs synchronous detection of the F _P, chip synchronization, bit synchronization to perform, subsequent information bits I ₁ ~I
_{In M} , the phase-synchronized despreading process is performed.

1 constituting the spectrum despreading code X9
As a code in a chip unit, the same code _Cmn as the spread spectrum code X3 on the first wireless station 100 side is used. Therefore, assuming that the spectrum despreading code output from the spectrum despreading code generator 9 is X9, the output X8 of the spectrum despreading unit 8 satisfies the following equation for each chip in an error-free ideal state. _{S mn + C mn = (I} m + C mn) + C mn = I m frame synchronization signals _{F 1, F 2, F 3} , ···, for the F _P, addition of the output X9 spectrum despreading code generating section 9 It is output as it is without processing. The spectrum despreading unit 8 integrates the addition result of _mod2 to S _mn and C _mn for each 1-bit section, and obtains the value of each information bit _Im
Is determined. The output X8 of the spectrum despreading unit 8 is error-corrected by the error correction
As an information signal X10.

The error rate measuring unit 11 measures the error rate of the despread output in the spectrum despreading unit 8,
It measures the degree to which the spectrum despread output is stably obtained as a result of despreading by the spectrum despreading code X9. For example, the output X8 of the spectrum despreading section 8, the m-th bit interval of the information signal, but it should certain value I _m that is output, C _m1, C _m2, ··· in the section if there is an error in C _mN, output only wrong number is not a I _m. The error rate of the despread output in the spectrum despreading unit 8 can be measured by counting this erroneous number in an M-bit section (that is, a section from m = 1 to M). A specific circuit will be described later with reference to FIGS. The memory 12 temporarily stores the measurement result X11 of the error rate measurement unit 11, and the contents are read out through the high-speed output control unit 13 and transmitted to the first wireless station 100.

In the above-described example, the output X7 of the binarized front end 7 consisting of 1 and 0 is despread. On the other hand, the output X7 of the front end 7 is
When output as an analog signal having a continuous amplitude without being binarized, 1 and 0 of the despreading code X9 are changed to 1 and −
A correlator in which the addition of mod2 is replaced by a multiplier or a matched filter may be used. In this case, the output X7 of the front end 7 and the despread code X9
Is detected by detecting a correlation output value with the value in each 1-bit section. This correlation output value is compared with a predetermined threshold value, and it is determined that each 1-bit section is 1 or 0. At this time, the quality of the despread output in the spectrum despreading unit 8 is measured by calculating the difference between the correlation output value and the ideal value. This quality reflects the line quality of the uplink from the first wireless station 100 to the second wireless station 200.

Next, an uplink in which the contents of the memory 12 are added to the second information signal and transmitted from the second wireless station 200 to the first wireless station 100 will be described. In the second radio station 200 in FIG. 2, the second information signal is converted into an error-correctable code by the error correction code conversion unit 14, and the output X14 of the error correction code conversion unit 14 The signal is synthesized with the output X13 of the output control unit 13 and spread by the spectrum spreading unit 16.

The output X15 of the synthesizing unit 15 includes an M-bit signal sequence J ₁ , J ₂ ,..., J _M obtained by passing the second information signal through the error correction code conversion unit 14, and a high-speed output control. Part 13
From the signal sequence E ₁ outputted with the same 1-chip units and the spread spectrum code, E _2, ···, it is obtained by combining the E _M in series. Here, the signal trains E ₁ , E ₂ ,..., E _M
Is the error rate of the despread output measured by the error rate measuring unit 11.

The output X16 of the spread spectrum unit 16 is:
Assuming that the spread spectrum code output from the spread spectrum code generation section 17 is X17, the following equation holds for each chip. Here _{J m + D mn = T mn} E m + D xm = T xm, J m is the information bits constituting the output X15 of the combining unit 15 with respect to the output X14 of the error correction code conversion section 14, D _mn spread spectrum The code is a chip unit code constituting the spread spectrum code X17 output from the code generation unit 17. Further, T _mn is the frame synchronization signal F _1, F _2, ···, in a section excluding the F _P, represents the sign of the chip units constituting the output X16 of the spread spectrum unit 16.

The signal trains E ₁ , E ₂ ,..., E _M arranged at the rear of the output X 15 of the synthesizing unit 15 indicate the error rate of the despread output in the spectrum despreading unit 8. , Of the spread spectrum code X17, D _X1 ,
D _X2, ···, subjected to diffusion by D _XM, the output X16 of the spread spectrum unit _{16, T X1, T X2,} ···, is output as T _XM. Again, the frame synchronization signals F ₁ , F
_{2, F 3, ···, F} P is, spread spectrum codes X1
No addition processing of mod2 with 7 is performed. The output X16 of the spread spectrum unit 16 is amplified by a power amplifying unit 18 similar to the power amplifying unit 4 shown in FIG.

In the first radio station 100 shown in FIG. 1, this radio wave is received by the receiving antenna 20, and the same as the output X16 of the spread spectrum unit 16 via the front end 21 similar to the front end 7 shown in FIG. A signal sequence X21 is obtained. When the spectrum despread code output from the spectrum despread code generator 23 is X23, the output X22 of the spectrum despreader 22 satisfies the following equation for each chip in an error-free ideal state. _{T mn + D mn = (J} m + D mn) + D mn = J m T xm + D xm = (E m + D xm) + D xm = E m

Here, the spectrum despreading code X23
For example, D _mn and D _xm which are the same codes as the codes of the chip units constituting the spread spectrum code X17 shown in FIG. 2 are used. The frame synchronization signals F ₁ , F ₂ , F ₃ ,.
-, for the F _P, it is output as it is. The spectrum despreading unit 22 integrates the result of addition of mod2 to T _mn and D _mn for each 1-bit interval, and obtains the value J of each information bit.
Determine _m . Output X22 of spectrum despreading unit 22
Are error-corrected by the error correction processing unit 24 and are output as the received second information signal.

The signal quality of the front-end output X21 received by the first wireless station 100 is determined by the error rate measurement unit 25.
Is measured by The error rate measuring section 25 is similar to the error rate measuring section 11 shown in FIG. 2, and measures the error rate of the despread output in the spectrum despreading section 22. It measures how much spectrum despread output is obtained stably as a result of the spread. This error rate includes
The line quality of the uplink from the second wireless station 200 to the first wireless station 100 is reflected. A specific circuit will be described later with reference to FIGS.

The quality information reading section 26 receives the signal trains E ₁ , E ₂ ,..., E sent from the second wireless station 200.
_M , that is, the error rate of the despread output in the spectrum despreading unit 8 measured by the error rate measuring unit 11 in the second wireless station 200 is read.

The evaluation section 27 receives the measurement result of the error rate measurement section 25 and the read value of the quality information reading section 26, finds an average value for a predetermined number of measurements, and obtains a first transmission quality display section 28 And the second transmission quality display unit 29, and controls to adaptively change the transmission quality and transmission efficiency of the first information signal transmitted from the first wireless station 100.

In this case, the first transmission quality display section 28 displays the average value of the measurement results of the error rate measurement section 25 for the predetermined number of measurements as it is. When the measurement result of the error rate measurement unit 25 is equal to or smaller than a predetermined value, that is, when the second radio station 20
When the uplink quality from 0 to the first radio station 100 is equal to or more than a predetermined value, the read value of the quality information reading unit 26 is calculated and displayed for an average value for a predetermined number of measurements. .

As a result, the value displayed by the second transmission quality display unit 29 is a signal sequence transmitted on the downlink from the first wireless station 100 to the second wireless station 200 for the first information signal. This is equivalent to displaying the bit error rate for I ₁ , I ₂ ,..., I _M by averaging. That is, the signal sequence E ₁ when the quality of the uplink from the second radio station 200 to the first radio station 100 is equal to or larger than a predetermined value, E _2, · · ·, E _M is a spectrum despreader 8
, The error rate of the despread output is correctly represented, which means that the signal sequences I ₁ , I ₂ ,.
.., I _M can be considered to represent the bit error rate. In fact, the above-mentioned error rate of the despread output has a relationship proportional to the bit error rate of the information signal.

In the CDMA radio transmission system, it is common to use the same frequency band for the uplink and the downlink, and from this point, the channel quality of the uplink and the downlink should be the same on average. is there. However, when the first information signal is transmitted from the first wireless station to the second wireless station,
There is a slight difference between the time when the first information signal is sent back from the second wireless station to the first wireless station. If the mobile station is an in-vehicle station that is traveling at high speed, the fluctuation period of fading becomes very short. Therefore, the line quality may vary greatly depending on the above-mentioned time lag. Therefore, as described above, the quality of the downlink from the first wireless station to the second wireless station is detected after removing the influence of the uplink channel quality. Also, the first wireless station 100 is a base station,
When the second wireless station is a mobile station, the quality of the uplink and the downlink may be different because the respective wireless transmission facilities are significantly different.

FIG. 3 is an explanatory diagram showing output signals of respective units in the process of processing the first information signal transmitted from the first wireless station shown in FIG. 1 to the second wireless station shown in FIG. is there.
The output X1 of the error correction code conversion unit 1, the frame synchronization signal F ₁ to the head _{unit, F 2, F 3, ···} , F P is added,
Thereafter, a series of code strings each followed by a signal string of _M information bits I _{1 to} I M each having a predetermined section of 1 bit are shown, and an example is shown in which the signal string is intermittently transmitted a plurality of times at intervals. ing. In the figure, the frame synchronization signals F ₁ , F ₂ , F
₃ ,..., F _P are simply described, for example,
A PN sequence or a similar signal sequence is used, and the unit time length of each of the codes F _{1 to} F _P is equal to the unit time length of one chip, and the frame synchronization signals F ₁ , F ₂ , F ₃ ,.
..., the entire length of the F _P may be an integral multiple of one bit interval. The frame synchronization signal may be obtained by using the spread spectrum code X3 itself for a plurality of cycles.

[0032] In the second radio station 200, and the like to the front end 7 providing the synchronization unit, the frame synchronization signals _{F 1, F 2, F 3} , ···, using F _P bit synchronization and chip Synchronization is performed, and the subsequent information bits are subjected to phase-synchronized despreading.

The spread spectrum code X3 is a PN sequence of N chips per bit section. With different symbols for each bit interval in the _{figure, C 11 ~C 1N, ···,} C M1 ~
Although shown as C _MN , P
N sequences may be used. Output X2 of spread spectrum section 2
, Each information bit forming the output X1 of the error correction code conversion unit 1 as described above I _m spread spectrum codes X3
, And mod2 is added to the code C _{mn in} units of one chip to form a spread code string represented as S _{11 to} S _1N ,..., S _{M1 to} S _MN . At the beginning, the frame synchronization signals F ₁ , F ₂ , F ₃ ,..., _FP are added as they are.

In the second radio station 200 shown in FIG.
, The signal sequence F ₁ , which is the output X2 of the spread spectrum unit 2,
_{F 2, F 3, ···,} F P, S 11 ~S 1N, ···, S M1
~S _MN is, has emerged as the output X7 of the front end 7 and τ ₁ delay. The spectrum despreading code X9 is identical reference numerals C ₁₁ and spread spectrum code X3 -C _1N, · ·
・, C _{M1 to} C _MN are used. Output X8 of the inverse spread spectrum unit 8 calculates the sum of each information constituting the output X7 of the front end 7 bits S ₁₁ to S _1N, · · ·, to the spectrum despreading code X9 described above with S _M1 to S _MN mod2 And the information bits I _{1 to} I _M are restored by despreading.
Frame synchronization signal _{F 1, F 2, F 3} , ···, for the F _P, despreading processing is output as not performed.

FIG. 4 is an explanatory diagram showing output signals in the process of processing the first and second information signals transmitted from the second wireless station shown in FIG. 2 to the first wireless station shown in FIG. It is. Combining section 1 in second wireless station 200 shown in FIG.
5, the output X15 of the frame synchronization signal F ₁ , F
_2, F _3, · · ·, is added F _P, thereafter, M information bits J _1, J _2, each having a predetermined interval of 1 bit, · · ·, J _M followed, the rearmost , E _M , which is the error rate of the despread output in the spectrum despreading unit 8, each bit of the signal sequence E ₁ , E ₂ ,. It is.

On the other hand, the spread spectrum code X17 is a code string of N chips per bit section, similar to the spread spectrum code X3, and uses a PN sequence different from the spread spectrum code X3. In the figure, the symbols are different for each bit section, and D _{11 to} D _1N ,..., D _{M1 to} D _MN
, And in the section corresponding to the information bits I ₁ , I ₂ ,..., I _M received from the first wireless station 100, D _X1 ,
Although D _X2 ,..., D _XM are shown, a PN sequence having one cycle of a bit section may be used.

The output X16 of the spread spectrum unit 16 is
Regarding the signal sequence output X14 of the error correction code conversion section _{14, T 11 ~T 1N, ···} , it is diffused to T _M1 through T _MN. Additionally, the signal sequence E ₁ as described above, E _2, · · ·, with regard E _M, spread spectrum code X17 relative to the addition of mod2, is converted to T _X1 through T _XM.

In the above description, the error rate is represented by an M-bit signal sequence E ₁ , E ₂ ,..., E _M and is sent back to the first wireless station 100. It may be represented by bits. The measurement accuracy increases as the number of bits representing the error rate increases. Conversely, when transmitting with a reduced number of bits, it is possible to shorten the length of a series of code strings to be transmitted, assuming that one bit of information bits is transmitted at high speed in one chip section. Therefore, the time required for transmission can be reduced. Also, assuming that one information bit is allocated to a section of a plurality of chips and transmitted at a slightly reduced transmission rate, the signal sequence E ₁ ,
The error rate of E ₂ ,..., E _M can be reduced.

In the first radio station 100 shown in FIG.
Signal sequence F which is the output X16 of the spread spectrum unit 16
₁ , F ₂ , F ₃ ,..., F _P , T _{11 to} T _1N ,.
_{T M1 ~T MN, T X1 ~T} XM is manifested as an output X21 of the front end 21 and tau ₂ delay. Spectrum despreading code X23 is same reference numerals D ₁₁ and code chip units constituting the spread spectrum code X17 shown in FIG. 2 to D
_1N, ···, D _M1 ~D _MN are used. Spectrum despreader 22, the information bits T ₁₁ through T _1N constituting the output X21 of the front end 21, ..., with respect to spectrum despreading code X9 described above and T _M1 through T _MN performs addition of mod2 , The information bit J of the despread second information signal
_{1 to} J _M and the signal trains E ₁ , E ₂ ,..., E _M are restored.

The error rate measuring unit 25 detects the despread output of T _{11 to} T _1N ,..., T _{M1 to} T _MN by the despreading code X23 for each 1-bit section to determine the error rate. Ask. On the other hand, the quality information reading unit 26 outputs the signal train E ₁ ,
E ₂ ,..., E _M are read, and the error rate of the despread output in the spectrum despreading unit 8 is obtained. This error rate reflects the line quality of the downlink from the first wireless station 100 to the second wireless station 200.

The evaluator 27 averages the error rates measured by the error rate measuring unit 25 over, for example, one transmission period or a plurality of transmission periods. The error rate read by the quality information reading unit 26 is a numerical value as sent from the second wireless station 200, provided that the error rate measured by the error rate measuring unit 25 is equal to or lower than a predetermined level. After being evaluated, an average value is obtained in the same manner.

FIG. 5 shows the error rate measuring unit 11 shown in FIG.
FIG. 3 is a circuit diagram showing one specific example. FIG. 6 is a waveform diagram showing the signal states of the respective units in FIG. The same applies to the error rate measurement unit 25. In the figure, 301 and 305 are D flip-flops, 302 and 306 are AND gates, 303 is a counter, and 304 is a parallel input / output register.

In the spectrum despreading unit 8 shown in FIG. 2, mod2 addition is performed.
The added output is input to the error rate measurement unit 11 and supplied to the D terminal of the D flip-flop 301 and the AND gate 302. The clock terminal of the D flip-flop 301 has 1
A pulse signal fCHIP having a chip cycle is input. On the other hand, a pulse signal fCLK having a one-bit cycle is input to a D terminal of the D flip-flop 305, and a pulse signal fC having a one-chip cycle is input to a clock terminal.
HIP is entered. D flip-flops 301 and 30
Reference numeral 5 denotes a one-chip delay circuit.

The inputs of the AND gates 302 and 306 are D
Each of the flip-flops 301 and 305 is connected to a D terminal and a negative terminal of Q. AND gate 302
Connected to the clock input terminal of the counter 303, AND
Gate 306 is connected to the reset terminal of counter 303. The parallel output terminal of the counter 303 is connected to the parallel input of the parallel input / output register 304. The parallel input / output register 304 outputs a pulse signal fC having a 1-bit cycle.
LK is a clock input, and its output is a quality information output.

A specific example of the first error rate measurement section shown in FIG. 5 will be described with reference to FIG. Here, as a simple circuit example, I of the output X8 of the spectrum despreading unit 8
In the interval m, the quality of the despread output in the spectrum despreading unit 8 is determined by digitally examining how much the output X7 of the front end 7 and the output of the mod2 addition to the spectrum despread code X9 are in a constant state. Will be described. The output of mod2 addition does not become constant depending on the degree of interference wave or noise when there is much. In the example of FIG. 6, t1 and t5 are bit breaks of the information signal, and t2, t3 and t4 indicate portions where the output is inverted due to interference, noise, or the like.

When the output of the mod2 addition rises, a pulse is generated at the output X302 of the AND circuit 302.
Similarly, a pulse is generated at the output X306 of the AND circuit 306 when the bit signal fCLK rises. The output of the AND gate 302 is the counter 30
Counted by three. The counter 303 is reset at the beginning of the information bit and at times t1 and t5.

The counter 303 counts pulses of the output X302 of the AND circuit 302 generated at times other than t1 and t5, and the count result is latched by the next parallel input / output register 304. That is, the output of the parallel input / output register 304 includes A, excluding the points in time t1 and t5.
The number of pulses of the output X302 of the ND circuit 302 is output, and this value is determined by Jm of the output X22 of the spectrum despreading unit 22.
Shows how stable the despread output is in a constant state in the section of. The quality information obtained in this way means that the higher the output value of the parallel input / output register 304 corresponding to (proportional to) the error rate, the more the quality is degraded.

In the embodiment of the present invention, the transmission quality of the information signal transmitted by the first wireless station 100 (own station) can be detected by the second transmission quality display unit 29. The transmission power of the first wireless station 100, the transmission speed of the information signal, the error correction capability of the information signal, and the like are changed in accordance with the result to control both the transmission quality and the transmission efficiency of the information signal to an appropriate state. can do.

Hereinafter, several examples of the control of the transmission quality and the transmission efficiency of the information signal will be described in detail. First, the control of the transmission power will be described. If the transmission power is increased more than necessary, not only does it interfere with radio stations other than the other station, but it also causes a loss in terms of power consumption of the own station. Therefore, if the required transmission power for the own station is secured,
It is desirable to control so as not to exceed it. To this end, the transmission power control unit 30 shown in FIG. 1 is provided, which receives a control signal from the evaluation unit 27 and reduces the power so that the transmission power is reduced as long as the bit error rate of the information signal does not deteriorate. The transmission efficiency is improved by controlling the amplifier 4.

Next, control of the transmission rate will be described.
When the chip rate is constant, the transmission rate of the information signal decreases as the number of chips of the spreading code for one bit of information (the value of N in FIG. 2) increases, but the bit error rate of the information signal decreases and the transmission quality increases. Will be higher. However, an increase in the number of chips per bit means that a given frequency for transmitting an information signal is occupied for a longer time, and transmission efficiency with respect to frequency and time is reduced. That is, when the information transmission speed is low, the transmission quality is improved but the transmission efficiency is reduced. Conversely, when the information transmission speed is high, the transmission quality is deteriorated but the transmission efficiency is improved. Therefore, it is desirable to control the transmission speed of the information signal transmitted from the own station to an appropriate value. For this purpose, a transmission rate control unit 31 is provided, which receives a control signal from the evaluation unit 27 and receives the error correction code conversion unit 1,
By controlling the spread spectrum unit 2 and the spread spectrum code generation unit 3, the transmission rate of the information signal of the own station is changed to an appropriate value.

The control in this case is performed so that the transmission quality of the first information signal transmitted from the own station becomes a minimum required value. That is, when the chip rate is constant, the first
When the transmission quality and the transmission efficiency of the information signal are changed according to the average value of the bit error rates indicated by the above-mentioned second transmission quality display unit 29, and the average value of the bit error rates indicates a high value, Since the transmission quality is too low, the transmission quality of the first information signal is increased by increasing the number of spreading code chips corresponding to one bit of the information signal, and when the average value of the bit error rate indicates a low value, the transmission quality is low. Therefore, the transmission efficiency of the first information signal is increased by reducing the number of chips of the spreading code corresponding to one bit of the information signal. The despreading code on the receiving side also needs to be changed accordingly, and a control information signal for changing the despreading code needs to be transmitted from the first wireless station 100 to the second wireless station 200.

The same thing as the above-described control of the transmission rate is performed.
The same can be said for error correction codes. The longer the inter-code distance is made by increasing the error correction capability of the error correction code, the longer it takes to transmit one piece of information, but the smaller the bit error rate after error correction of the information signal becomes, the higher the transmission quality becomes. Become. Conversely, the weaker the error correction capability of the information signal and the closer the inter-code distance, the shorter the time required for transmitting one piece of information, but the higher the bit error rate after performing error correction of the information signal and the higher the transmission quality. Will be lower.

That is, the higher the error correction capability, the higher the transmission quality of the information signal, but the longer the time occupied by the frequency provided for transmitting the information signal is, the more the frequency and time are reduced. Reduce transmission efficiency. Conversely, when the error correction capability is weakened, the time required for transmitting the information signal is shortened, and the transmission efficiency with respect to frequency and time is improved.

Therefore, it is desirable to control the error correction capability of the first information signal transmitted from the own station to an appropriate value. For this purpose, an error correction control unit 32 is provided, which controls the error correction code conversion unit 1 in response to a control signal from the evaluation unit 27, so that the error correction capability related to the transmission of the first information signal is appropriately adjusted. Variable. The control in this case is also performed so that the transmission quality of the first information signal becomes a minimum required value. That is, the transmission quality and transmission efficiency of the first information signal are changed according to the average value of the bit error rate of the second transmission quality display unit 29.

In the above description, the case where various transmission controls such as control of transmission power, control of transmission speed, control of error correction capability of error correction code, etc. are individually performed in response to a control signal from the evaluation unit 27 is described. Although described, a plurality of transmission controls may be performed simultaneously.

In the above-described embodiment of the present invention, since the transmission quality of the information transmitted by the own station is detected by the own station, it is determined whether the quality has reached a predetermined value. If it is possible to judge by the own station and it is judged that the predetermined value is not reached, a transmission control procedure for retransmitting information can be adopted.

In the above-described embodiment of the present invention, since the information signal transmitted by the own station is monitored by the own station, it can also be used for failure diagnosis of the own station. That is, when the state that the transmission quality of the information transmitted by the own station does not reach the predetermined value has continued for a certain period of time or more,
It can be determined that the transmission system is abnormal. In this case, transmission can be stopped following the failure diagnosis. In fact, continuing to uselessly transmit radio waves that are not normally received by the other station is not only a waste of frequency resources,
Large loss such as interference to other stations.

[0058]

As is apparent from the above description, the present invention measures the transmission quality of the information signal transmitted by the own station at the partner station, and then measures the measurement result from the partner station at a high transmission rate. By transmitting the data to the station, there is an effect that the transmission quality of the wireless channel from the own station to the partner station can be detected by the own station. In addition, when the wireless link from the partner station to the own station is sufficiently reliable, processing for obtaining an average value of the measurement results sent from the partner station is performed. Therefore,
The transmission quality of the information signal transmitted by the own station, without significantly impairing the transmission efficiency of the information, and in a state where the reliability of transmission of "information on transmission quality" from the partner station to the own station is sufficiently ensured. There is an effect that it can be detected. As a result, it is possible to control the transmission quality and the transmission efficiency of the information signal transmitted by the own station to an appropriate state, to retransmit information having poor transmission quality, or to easily diagnose the failure of the transmission system of the own station. There is an effect that can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first wireless station for explaining an embodiment of a CDMA wireless transmission system according to the present invention.

FIG. 2 is a block diagram of a second radio station for explaining an embodiment of the CDMA radio transmission system of the present invention.

FIG. 3 is an explanatory diagram showing output signals of respective units in a process of processing a first information signal transmitted from the first wireless station shown in FIG. 1 to the second wireless station shown in FIG. 2;

FIG. 4 is an explanatory diagram showing output signals in a process of processing first and second information signals transmitted from the second wireless station shown in FIG. 2 to the first wireless station shown in FIG. 1;

FIG. 5 is a circuit diagram showing a specific example of an error rate measurement unit 11 shown in FIG.

FIG. 6 is a waveform chart showing signal states of respective units in FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 First wireless station 200 Second wireless station 1,14 Error correction code converter 2,16 Spectrum spreader 5,19 Transmit antenna 6,20 Receive antenna 8,22 Spectrum despreader 10,24 Error correction processor 11, 25 Error rate measurement unit 26 Quality information reading unit 27 Evaluation unit 28 First transmission quality display unit 29 Second transmission quality display unit 301, 305 D flip-flop 302, 306 AND gate 303 Counter 304 Parallel input / output register

Claims (5)

[Claims] 1. A first information signal is spread from a first wireless station to a second wireless station by a first spreading code and transmitted, and a second information signal is transmitted from the second wireless station to the first wireless station. In a CDMA wireless transmission system for transmitting the second information signal by spreading the second information signal with a second spreading code, the second wireless station measures a transmission quality of the received first information signal;
The transmission quality measured by the first means is added to the second information signal at a transmission rate higher than the transmission rate of the second information signal, and then spread by the second spreading code and transmitted. A second means for receiving the second information signal and measuring a transmission quality of the second information signal; and a second means for receiving the second information signal and measuring a transmission quality of the second information signal. Fourth means for reading the transmission quality measured by the first means sent from the station, and reading of the fourth means when the transmission quality measured by the third means is equal to or more than a predetermined value. Detecting the transmission quality of the first information signal sent from the first wireless station to the second wireless station based on the value
A CDMA wireless transmission system comprising: 2. The method according to claim 1, wherein the first unit measures a transmission quality based on an error rate of a despread output of the received first information signal. 2. The CDM according to claim 1, wherein the transmission quality is measured based on an error rate of a despread output of the information signal.
A wireless transmission system. 3. The fifth means is for obtaining an average of the values read by the fourth means when the measurement result of the third means is equal to or more than a predetermined value, and When the average value is high, there is provided sixth means for controlling the transmission efficiency of the first information signal so that the transmission quality of the first information signal is increased when the average value is low. 3. The CDMA wireless transmission according to claim 1, wherein the transmission quality and the transmission efficiency of one information signal are adapted to the line quality in a direction of transmission from the first wireless station to the second wireless station. method. 4. A measurement result of the third means is equal to or more than a first predetermined value, and a value read by the fourth means is a second predetermined value.
The first wireless station retransmits the transmitted first information signal to the second wireless station when the fifth means detects that the value is equal to or less than a predetermined value. CDMA according to any one of claims 1 to 3, characterized in that:
Wireless transmission method. 5. A measurement result of the third means is equal to or more than a first predetermined value, and a value read by the fourth means is a second predetermined value.
Wherein the first wireless station stops transmitting the first information signal when the fifth means detects that the state of being equal to or less than a predetermined value has continued for a predetermined time or more. CDMA according to any one of claims 1 to 4,
Wireless transmission method.