JP3091649B2 - Diversity device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity device.

[0002]

2. Description of the Related Art Conventionally, in a digital communication device, a carrier signal is modulated with a digital information signal (baseband signal) in order to improve transmission efficiency.
Information signals are being transmitted. As such a modulation method, an amplitude modulation method (A) in which the amplitude of a carrier signal is changed according to a digital baseband signal (modulation signal).
SK: Amplitude Shift Keyin
g), a frequency modulation method (FSK: Frequency Shif) for displacing the frequency of the carrier according to the modulation signal
t Keying), a phase modulation method (PSK: Phase Shim) that changes the phase of a carrier according to a modulation signal.
ft Keying), a quadrature amplitude modulation method (QAM: Quadrature Amplitude) in which the amplitude and phase of a carrier wave are independently changed according to a modulation signal.
e Modulation).

[0003] It is known that when these digital modulation methods are applied to mobile communication or the like, the reception performance is significantly deteriorated by a fading phenomenon in which the reception level fluctuates drastically due to the influence of reflection and scattering of radio waves. As an effective method for compensating for a decrease in the reception level due to the fading, diversity reception or the like that performs reception using a plurality of reception systems has been put to practical use.

[0004] Diversity receiving systems include a selective combining system for selecting and demodulating a received signal having a maximum receiving level in each receiving system, and an equal gain for combining and demodulating signals of each receiving system at an equal level. There is a combining method, and a maximum ratio combining method in which signals of the respective receiving systems are weighted in proportion to the reception level, then combined and demodulated. Among these, the maximum ratio combining method provides the best characteristics, but the device becomes complicated because a linear receiving system is required and the phase of the modulated wave signal is adjusted with high accuracy, and the cost is low. It was difficult to realize.

FIG. 6 shows an example of a conventional maximum ratio combining diversity receiver, which is configured to combine four systems of received signals. In this device, each input terminal 10
The received signals input from 1, 102, 103 and 104 are made equal in carrier wave phase by phase shifters 105, 106, 107 and 108, then synthesized by adder 109 and demodulated by demodulator 110. The demodulation is performed.
At this time, each signal is linearly amplified until the signal is synthesized by the adder 109, and thus the synthesis is performed linearly.

FIG. 7 is a diagram showing the signal synthesis of the device according to the prior art shown in FIG. 6 on the IQ plane. Only two systems are shown for simplicity. In FIG. 7, S1 and S2 denote received signals, and S1S and S1N denote signal components and noise components of S1 and S2.
S and S2N are a signal component and a noise component of S2. In general, the noise component is added almost constantly regardless of the signal level and the receiving system (hereinafter, referred to as a branch). Therefore, in the drawing, the received signal of each branch has the same radius (||) centered on the signal component (S1S and S2S). S1N | = | S2N |) is shown as a point on the circumference. In the apparatus shown in FIG. 6, that is, in the maximum ratio combining diversity, the received signals of the respective branches are linearly combined, and therefore, the combined signal of S1 and S2 in a vector form is the combined signal input to the demodulator.

As described above, in the maximum ratio combining diversity, since the signals are linearly combined, the signal components are combined with the noise component kept constant. As a result, the S / N of the combined signal can be maximized, so that the maximum ratio combining diversity can obtain the best reception performance among the diversity systems.

[0008]

Since the maximum ratio combining diversity can maximize the S / N of a signal, it is an optimum combining method in a propagation environment where only thermal noise exists. However, when the received signal includes an interference wave such as a delayed wave other than the thermal noise, the influence of the interference wave cannot be positively mitigated in the maximum ratio combining diversity because the signal is simply linearly combined. In particular, when a branch having a high reception level includes many interference waves such as a delay wave, the reception quality is badly weighted despite the poor reception quality,
There is a problem that the receiving performance is significantly deteriorated. In addition, in combining diversity, it is necessary to output a detection result as I and Q in order to weight the detection output.
Baseband differential detection was used. Since the baseband differential detection is performed by the vector (I, Q) calculation, the multiplication process is frequently used. In this baseband differential detection, a matrix operation must be performed, and the processing is complicated. Therefore, there has been a problem that the scale must be large and that a plurality of LSIs and DSPs need to be used.

[0009]

In order to solve the above-mentioned problems of the prior art, a diversity apparatus according to the present invention comprises a plurality of phase detection type delay circuits for outputting reception phase delay detection data relating to phases of a plurality of reception signals. Detection means, means for outputting composite coefficient data for performing weighting based on the phase delay detection data, and the sine of the phase delay detection data and the composite coefficient data and the phase delay detection data being input and A plurality of first means for outputting a product of combined coefficient data; and a plurality of second means for receiving the combined coefficient data and the phase delay detection data and outputting a product of a cosine of the phase delay detection data and the combined coefficient data. Means, a first adder for adding the output data of the plurality of first means, and a second adder for adding the output data of the plurality of second means. It is characterized in.

[0010] Further, the diversity device according to the present invention comprises:
A plurality of phase detection type delay detection means for outputting reception phase delay detection data relating to the phases of the plurality of reception signals, and a likelihood detection means for outputting likelihood data relating to an amount of deviation of the phase delay detection data from an ideal determination point Means for outputting combined coefficient data for performing weighting based on reception level data and the likelihood data regarding the size of a received signal,
A plurality of first means for receiving the combined coefficient data and the phase delay detection data and outputting a product of a sine of the phase delay detection data and the combined coefficient data; and receiving the combined coefficient data and the phase delay detection data as input. A plurality of second means for outputting a product of a cosine of phase delay detection data and the combined coefficient data; a first adding unit for adding output data of the plurality of first means; and a plurality of second means. And a second adding section for adding the output data of the above.

[0011]

According to the first aspect of the present invention, the phase of the received signal is detected by the phase detection means.
The detected phase data is delayed by one symbol by delay means,
The difference between the output data of the delay means and the phase detection means is calculated by the calculation means. Further, the output data of the calculation means is given to the addresses of the storage means 1 and the storage means 2, and is output from the combined coefficient output means. Storage means 1 for storing the combined coefficients
By giving it to another address of the storage means 2, the product of the sine and cosine of the phase delay detection data and the combined coefficient data is output, and the data of the plurality of reception systems output from the storage means 1 and the storage means 2 are output. Is added.

According to the second aspect of the present invention, the phase of the received signal is detected by the phase detecting means, and the detected phase data is delayed by one symbol by the delaying means. The difference is calculated by the calculation means, and
The output data of the calculating means is given to the addresses of the storing means 1 and the storing means 2, and the reception level correction data corrected by the likelihood data detected by the likelihood detecting means is stored in the storing means 1 and the storing means. The data of a plurality of receiving systems output from the storage unit 1 and the storage unit 2 are given to another address of the unit 2 and added.

[0013]

FIG. 1 is a diagram showing a first embodiment of the present invention. In FIG. 1, reference numerals 1, 2, 3 and 4 denote input terminals of each branch to which a received signal is inputted, 5, 6, 7 and 8 denote phase detecting means for detecting the phase of the received signal, 9, 10, 1
1 and 12 are delay means for delaying the data of the phase detection means 5, 6, 7, 8 by one symbol time, 13, 14, 15
And 16 are calculation means, and 17, 18, 19 and 20 are synthesis coefficients for outputting a synthesis coefficient for performing weighting for each branch from the phase delay detection data output from the calculation means 13, 14, 15, and 16. Output means, 21, 22,
23 and 24 are synthesis coefficient output means 17, 18, 19,
First means for outputting the product (Cn · SIN (θn)) of the sine of the phase delay detection data and the synthesis coefficient data using the combined coefficient data (Cn) from 20 and the phase delay detection data (θn) as addresses; , 27 and 28 are the combined coefficient data from the combined coefficient output means 17, 18, 19 and 20
(Cn) and the phase delay detection data (θn) as an address, the product of the cosine of the phase delay detection data and the combined coefficient data (C
n · COS (θn)), 29 and 30 are adding means, 31 is a judging means for decoding transmission data from the data of the adding means 29 and 30, and 32 is a data from the data of the adding means 29 and 30 This is a clock recovery unit that outputs a clock synchronized with transmission data.

In FIG. 1, the portion comprising the phase detecting means 5, 6, 7, 8 and the delay means 9, 10, 11, 12 and the calculating means 13, 14, 15, 16 of each branch is a phase detection type of differential detection. Make up the vessel. That is, in this part, the phase detection means detects the phase of the received signal, the detected phase is delayed by one symbol time by the delay means, and the difference between them is detected by the calculation means, whereby the phase delay detection data (θn) is obtained. Output.

In the diversity apparatus according to the present invention, the I component, the Q component, and the synthesis coefficient of the detection signal are calculated from the phase delay detection data, and the I component and the Q component are weighted by the synthesis coefficient and then synthesized.

FIG. 2 shows the operation of the apparatus of this embodiment shown in FIG.
This is shown on the Q plane. In the phase detection type delay detector, since the amplitude information of the received signal is lost, all the signals are represented by vectors having the same magnitude on the IQ plane.
That is, the received signal is represented by a point on the circumference centered on the origin, and it is assumed that the received signal 1 and the received signal 2 shown in the figure are combined.

From the phase delay detection data (θ1, θ2) output from the calculating means, first, the I component of the detection signal,

[0018]

(Equation 1)

And Q component

[0020]

(Equation 2)

Is obtained.

Next, the I and Q components are weighted with the combined coefficient data C1 and C2 from the combined coefficient output means, and the weighted I component before combining is obtained.

[0023]

(Equation 3)

And Q component

[0025]

(Equation 4)

The signals from the branches are combined by adders 29 and 30, and the I component, Q component,

[0027]

(Equation 5)

Is obtained.

Here, as shown in FIG. 3, the synthesis coefficient is the amount of deviation L of the decision point of the phase delay detection data from the discrimination level.
Use 1 (≧ 0), L2 (≧ 0)

[0030]

(Equation 6)

Alternatively, coefficient conversion is performed using L1 and L2 as inputs and using an arbitrary function f (x),

[0032]

(Equation 7)

[0033]

Since this operation can be uniquely obtained from the phase delay detection data, it can be realized by table conversion using storage means. As an example, RO means
Considering the case of using M, this processing can be performed by inputting the phase delay detection data to the address and extracting the calculation data written at the address indicated by the data.

Also, if the weighted I component (S1I ', S2I') and Q component (S1Q ', S2Q') prior to combining are known from the phase delay detection data θ and the combining coefficient C,

[0036]

(Equation 8)

Can be uniquely obtained. Therefore, it is possible to write the calculation results of the I and Q components in advance in the storage means and obtain the results by table conversion.

Furthermore, the combined coefficient output means and the storage means are integrated, the phase delay detection data of the discrimination point is provided to the upper address, the combined count data is provided to the lower address, and the calculation data written at the address indicated by the data is taken out. You can also do that.

FIG. 4 is a diagram showing a second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In FIG. 4, 33, 34, 35 and 3
6 is a likelihood detecting means for outputting likelihood data from the phase delay detection data outputted from the calculating means 13, 14, 15 and 16, and 37, 38, 39 and 40 are receiving level data (RSSI) and likelihood data. This is a composite coefficient control unit that mainly performs composite coefficient data from data.

In the apparatus according to the second embodiment, the I component and the Q component of the detected signal are calculated from the phase delay detection data, and are weighted by the combining coefficients from the combining coefficient control means 37 to 40, and then combined. Things.

In the second embodiment, as in the first embodiment, first, based on the phase delay detection data (θ1, θ2) output from the calculating means 13 to 16, the I component of the detection signal,

[0042]

(Equation 9)

And the Q component

[0044]

(Equation 10)

Is obtained.

Next, the I and Q components are weighted with data C1 and C2 from the combining coefficient output means, and the weighted I component before combining is obtained.

[0047]

[Equation 11]

And Q component

[0049]

(Equation 12)

The signals from the respective branches are combined by adders 29 and 30, and the I component, Q component,

[0051]

(Equation 13)

Is obtained.

Here, the combination coefficient is obtained by converting the reception level data (Rn) into the likelihood of the phase delay detection data (L1, L2 in FIG. 3).
Determined by controlling according to 2).

FIG. 5 shows this combination coefficient control means. First, Rn is input to the comparator 41, and R
n is compared with the set level. Here, when Rn is equal to or lower than the set level, the switch 42 is switched to the contact A side, and Rn
Is output as it is as Cn (multiplication coefficient = 1). Rn
Is higher than the set level, switch 42 is set to contact B
Side, and the multiplication coefficient (A
n) and

[0055]

[Equation 14]

Is calculated and output by the multiplication coefficient operation circuit 43. An arbitrary function can be used to calculate the multiplication coefficient from the likelihood data. Further, the multiplication coefficient may be set to 1 (no attenuation) for the likelihood exceeding a certain set value, and the multiplication coefficient may be given at the set value or more.

In the second embodiment of the present invention, when the reception level data is large, that is, when the reception level is large, the S / N is good, and when no interference wave or the like is included, the likelihood increases. The multiplication coefficient becomes 1, which is equivalent to a state where no control is performed. That is, the branch having no interference wave functions in the same manner as the normal maximum ratio combining diversity. On the other hand, when the interference wave is strongly included, the likelihood is reduced, the multiplication coefficient is reduced, and the output data from this branch is reduced. As a result, the influence of the interference wave can be reduced. In addition, when the reception level data is small, the S / N is poor, so that even if the likelihood is small, it is not possible to judge the influence of the interference wave in a straightforward manner. Is the judgment condition.

These operations are the same as in the first embodiment.
Needless to say, this can be realized by table conversion using storage means or the like.

[0059]

According to the present invention, a maximum ratio combining diversity device capable of reducing the influence of an interference wave is constituted by only a small-scale digital circuit suitable for IC such as a memory, an adder, and a shift register. And it is not necessary to use an expensive DSP or the like. Furthermore, since the signal input to the device of the present invention does not need to be linear, the wireless circuit can perform nonlinear amplification with a simple configuration. Due to these synergistic effects, according to the present invention, a conventional device having the same function can be configured very inexpensively, and the cost of the entire wireless device using the device of the present invention can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating signal synthesis on an IQ plane for explaining the operation of the present invention.

FIG. 3 is a diagram illustrating determination points of phase delay detection data.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a block diagram showing a combination coefficient control unit.

FIG. 6 is a block diagram showing a conventional technique.

FIG. 7 is a diagram illustrating signal combining on the IQ plane of maximum ratio combining diversity.

[Explanation of symbols]

 1, 2, 3, 4 input terminals 5, 6, 7, 8 phase detection means 9, 10, 11, 12 delay means 13, 14, 15, 16 addition means 17, 18, 19, 20 synthesis coefficient output means 21, 22, 23, 24 First means 25, 26, 27, 28 Second means 29, 30 Addition means 33, 34, 35, 36 Likelihood detection means 37, 38, 39, 40 Synthesis coefficient control means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 7/00 H04B ⁷ /02-7/12 H04L 1/02-1/06

Claims (2)

(57) [Claims] 1. A plurality of phase detection type delay detection means for outputting reception phase delay detection data relating to the phases of a plurality of reception signals, and outputting composite coefficient data for performing weighting based on the phase delay detection data. Means for inputting the combined coefficient data and the phase delay detection data and outputting a product of a sine of the phase delay detection data and the combined coefficient data; and a plurality of first means for outputting the product of the combined coefficient data and the phase delay detection data. A plurality of second means for receiving detection data and outputting a product of a cosine of phase delay detection data and the combined coefficient data; a first adding unit for adding output data of the plurality of first means; And a second adder for adding the output data of the second means. 2. A plurality of phase detection type delay detection means for outputting reception phase delay detection data relating to the phases of a plurality of reception signals, and likelihood data relating to the amount of deviation of the phase delay detection data from an ideal judgment point. Means for outputting composite coefficient data for performing weighting based on reception level data relating to the size of a received signal and the likelihood data, wherein the composite coefficient data and the phase delay detection data are A plurality of first means for inputting and outputting a product of a sine of phase delay detection data and the combined coefficient data; and a cosine of the phase delay detected data when the combined coefficient data and the phase delay detected data are inputted. A plurality of second means for outputting a product of the combined coefficient data; a first adder for adding output data of the plurality of first means; and an output data of the plurality of second means. Diversity device characterized in that it comprises an adding means and a second adder for adding.