JPH11298443A - Radio receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly and also surely determine a transmission rate, also to reduce a circuit scale and to increase the number of storable uses by performing maximum ratio synthesis (RAKE synthesis) of a received signal of plural paths and determining a transmission rate by using a signal after the synthesis. SOLUTION: A received signal of plural paths is inputted to an inverse spreading means 101 and a wide baseband signal is converted into an original narrow band signal. A channel estimating means 102 performs channel estimation by using a pilot symbol that is currently received and pilot symbols received in the past. A rake synthesizing means 103 synthesizes a desired signal which is temporally separated according to a spread code from outputs of the means 101 and of the means 102 and converts it into one signal. A rate decision means 104 determines the transmission rate of a received signal by using an output signal of the means 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to CDMA (Cod)
e Division Multiple Accesses
s) The present invention relates to a wireless receiver applicable to the system.

[0002]

2. Description of the Related Art A conventional radio receiving apparatus determines a transmission rate in variable rate transmission by using a likelihood function used for rate determination before a maximum ratio combining (RAKE combining) of received signals of each path of each antenna branch. The reliability of the likelihood is increased by adding (power addition) the square values of the calculated values and the obtained values. This conventional method of determining the transmission rate of a wireless receiver will be described with reference to the drawings.

FIG. 2 is a block diagram showing an overall configuration of a conventional radio receiving apparatus. In the conventional radio receiving apparatus, a radio signal taken from space by an antenna 200 is converted into an electric signal, and a despreading means 201 converts a wideband baseband signal spread on a frequency axis into an original narrowband signal. To the output of the despreading means 201, the repetitive symbol adding means 202 adds the same data symbol transmitted continuously plural times and converts it into one data symbol.

The output of the repetitive symbol adding means 202 is combined with a desired signal temporally separated by a spreading code by a RAKE combining means 203 and converted into one signal.
The QPSK demodulation unit 204 converts the QPSK-modulated parallel data (symbol) into serial data (bits), and the decoding unit 205 converts the coded data bits into a signal before coding to obtain received data. .

[0005] Rate determining means 206 estimates and determines the transmission rate of the transmitted signal from the received signal. Channel estimating means 207 receives a predetermined signal and estimates the characteristics of the propagation path.

FIG. 3 shows that the rate determining means 206
FIG. 3 is a diagram illustrating a slot configuration of variable rate transmission. FIG.
FIG. 3A shows a slot configuration at a full rate, and FIG.
(B) and (c) are 1/4 at 1/2 rate, respectively.
The slot configuration at the time of rate is shown. On the transmitting side, transmission power control signals 2, 12, and 22 and transmission data 3, 13, and 23 excluding pilot symbols 1, 11, and 21 are repeatedly transmitted. When the highest transmission rate (full rate) among the settable transmission rates is used, as shown in FIG. 3A, the symbol is repeated twice, and at the 1/2 rate and the 1/4 rate, the symbol is repeated 4 times and It is repeatedly transmitted eight times. Here, an inverted symbol is transmitted for the latter half of the repetition symbol.

In the radio receiving apparatus, after performing the despreading processing, the correlation / square calculation means 6, 16, 26 performs correlation / square calculation on symbols other than pilot symbols in order to determine the transmission rate of the received signal. I do. For example, the correlation / square operation means 6 first performs two-symbol correlation using the correlator 4 and then performs the square operation using the square operation means 5. The same applies to the correlation / square calculation means 16 and 26.

Here, in the two-symbol correlation, the correlation between the received signal and (1, -1) is calculated. The obtained square value (likelihood function) is added to the adder 7 by the amount obtained in the slot.
Are cumulatively added.

Similarly, correlation means 14 and 24 and squaring means 15 and 25 are performed on 4 and 8 symbols, and adders 17 and 27 perform cumulative addition. Where 4
In the symbol correlation, the received signal and (1, 1, −1, −
1), the received signal and (1, 1,.
1, 1, -1, -1, -1, -1) are calculated.

[0010] Since these three code sequences correlated with the received signal are orthogonal to each other, the correlation value for a code sequence length different from the number of repetition symbols is zero. The correlation value for the correct code sequence length is 1. These correlation, square, and addition operations are performed at each antenna branch and each finger of the receiver, and are cumulatively added for the purpose of increasing the reliability of the likelihood function. In order to further increase the reliability, cumulative addition for a plurality of slots is performed.

[0011] The repetition symbol addition means 202 adds the transmission rate corresponding to the code sequence length giving the maximum value among the finally obtained likelihoods as the transmission rate of the received signal. Then, after channel estimation means 207 performs channel estimation using pilot symbols, RAKE combining means 203 performs RAKE combining and QPSK demodulating means 204
Perform QPSK demodulation, and the decoding means 205 performs demodulation.

[0012]

However, in the above-mentioned conventional radio receiving apparatus, in order to determine the transmission rate with sufficient accuracy, cumulative addition must be performed over many slots. The processing time until the determination is made longer. As a result, until the transmission rate is determined, the transmission rate must be considered to be the maximum and the data must be stored, so that the required memory becomes large and the circuit scale becomes large. There is a point.

Further, since transmission power control cannot be performed while the transmission rate is unknown, the ability of the transmission power control to follow the propagation path fluctuations deteriorates. There is a problem that the number of possible users cannot be increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and aims to quickly and reliably determine a transmission rate, to reduce the circuit scale, and to increase the number of users that can be accommodated. It is an object of the present invention to provide a wireless receiving device capable of performing the following.

[0015]

The inventor of the present invention pays attention to the time loss caused by determining the transmission rate before performing the maximum ratio combining in the radio receiving apparatus, and combines the received signals of a plurality of paths with the maximum ratio combining. It has been found that by determining the transmission rate using the signal after the above, the processing time can be reduced, and the present invention has been made.

That is, the present invention is characterized in that the received signals of a plurality of paths are subjected to maximum ratio combining and the transmission rate is determined using the combined signals.

As a result, it is possible to shorten the processing time for determining the transmission rate and to reduce the circuit scale.

That is, the present inventor has solved the above-mentioned problem, and has improved the ability to follow the propagation path fluctuation in the transmission power control, thereby increasing the number of users that can be accommodated.

[0019]

1 is a block diagram showing a configuration of a radio receiving apparatus according to a first embodiment of the present invention; FIG. 2 is a block diagram showing a configuration of a radio receiving apparatus according to a first embodiment of the present invention; A configuration including a rate determination unit is adopted. Further, the invention of the wireless receiving method according to claim 4 employs a configuration in which received signals of a plurality of paths are subjected to maximum ratio combining and a transmission rate is determined using the combined signals.

According to these configurations, since the transmission rate can be determined after the maximum ratio combining of each antenna branch and each finger, the time required for obtaining sufficient rate determination accuracy can be reduced. Also, unlike the conventional case, it is not necessary to perform the correlation / square operation for each path, so that the processing time can be reduced, and the required memory and correlator are reduced, and the circuit scale can be reduced. Manufacturing costs can be reduced. Further, since the rate determination can be performed in a shorter time than in the conventional method, the transmission power control can be started earlier. In particular, when the moving speed of the mobile station device is high, the ability of the transmission power control to follow the fluctuation of the propagation path can be improved, and the number of users that can be accommodated can be increased.

According to a second aspect of the present invention, there is provided a mobile station apparatus having a configuration including the wireless receiving apparatus according to the first aspect.
The invention of a base station device according to claim 3 employs a configuration including the wireless receiving device according to claim 1.

According to these configurations, since the transmission rate can be determined after the maximum ratio combining of each antenna branch and each finger, the processing time can be reduced. In addition, since the rate determination can be performed in a shorter time than in the conventional method, transmission power control can be started earlier, the follow-up of transmission power control with respect to fluctuations in the propagation path is improved, and the number of users that can be accommodated can be increased. .

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a data receiving device according to one embodiment of the present invention.

[0024] The radio transmission apparatus (not shown) repeatedly transmits a transmission power control signal and data excluding pilot symbols, similarly to the conventional radio transmission apparatus.

On the other hand, on the radio receiving apparatus side, the antenna 10
0, the radio signal obtained from the space is converted into an electric signal, and the output of the antenna 100 is subjected to despreading processing by the despreading means 101, that is, the wideband baseband signal spread on the frequency axis is converted into the original narrowband signal. Convert to Channel estimating means 102 performs channel estimation using currently received pilot symbols and previously received pilot symbols. The RAKE combining means 103 includes the despreading means 10
1 and the output of the channel estimating means 102, a desired signal temporally separated by a spreading code is synthesized and converted into one signal.

Next, in order to determine the transmission rate of the received signal, the rate determining means 104 performs the correlation / square operation shown in FIG. 3 on the symbols excluding the pilot symbols. For example, in the correlation / square operation means 6, first, a two-symbol correlation is obtained using the correlator 4, and then the square operation means 5 performs a square operation. Here, in the two-symbol correlation, the correlation between the RAKE-combined received signal and (1, -1) is calculated.

The obtained square value (likelihood function) is cumulatively added by the adder 7 by the amount obtained in the slot. Similarly, for the 4 symbols and 8 symbols, the correlators 14, 2
Fourth and square calculation means 15 and 25 respectively perform correlation and square calculation, and adders 17 and 27 accumulate these.
Here, in the 4-symbol correlation, the received signal and (1,
In (1, -1, -1) and 8-symbol correlation, the correlation between the received signal and (1, 1, 1, 1, -1, -1, -1, -1, -1) is calculated.

Since these correlation / square / addition operations are performed after the maximum ratio (RAKE) synthesis of each antenna branch and each finger, a good correlation characteristic is obtained, and as a result, a good likelihood function is obtained. Can be Further, since it is not necessary to perform these operations on each antenna branch and each finger, the number of devices such as correlators can be significantly reduced, and the size of the entire device can be reduced.

Of the finally obtained likelihoods, the repetition symbol addition means 105 adds repetition symbols using the transmission rate corresponding to the code sequence length giving the maximum value as the transmission rate of the received signal. After that, the QPSK demodulation means 106 converts the parallel data (symbol) QPSK-modulated into serial data (bits), and the decoding means 207 converts the coded data bits into a signal before coding.
Get received data.

[0030]

As is apparent from the above description, according to the present invention, since the transmission rate can be determined after the maximum ratio combining of each antenna branch and each finger, sufficient rate determination accuracy can be obtained. The time required for the process can be reduced. Also, unlike the conventional case, it is not necessary to perform the correlation / square operation for each path, so that the processing time can be reduced, and the required memory and correlator are reduced, and the circuit scale can be reduced. Manufacturing costs can be reduced. Further, since the rate determination can be performed in a shorter time than in the conventional method, the transmission power control can be started earlier. In particular, when the moving speed of the mobile station device is high, the ability of the transmission power control to follow the fluctuation of the propagation path can be improved, and the number of users that can be accommodated can be increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a wireless reception device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of a conventional wireless receiving apparatus.

FIG. 3 is a diagram showing a slot configuration of variable rate transmission and functional blocks necessary for determining a transmission rate.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 antenna 101 despreading means 102 channel estimating means 103 RAKE combining means 104 rate determining means 105 iterative symbol adding means 106 QPSK demodulating means 107 decoding means

Claims (4)

[Claims] An R signal for maximum ratio combining of received signals of a plurality of paths.
A radio receiving apparatus comprising: AKE combining means; and rate determining means for determining a transmission rate using an output signal of the RAKE combining means. 2. A mobile station device comprising the wireless receiving device according to claim 1. 3. A base station device comprising the wireless receiving device according to claim 1. 4. A radio receiving method comprising: combining received signals of a plurality of paths at a maximum ratio; and determining a transmission rate using the combined signal.