JP2002344224A - Code division adaptive array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sequential addition-type code division adaptive array antenna, which is capable of switching weighting factors that are multiplied by signals which are received through antenna elements for the signals sampled, at the same time. SOLUTION: Switching indications, transmitted from switching timing units 7-n (n=1 to N) to weighting factor registers 5-n, are successively delayed by a time τ, each time n is incremented by one; for instance, counting signals are sent to all the switching timing units through a common line, and it is so set that a switching indication is outputted, when a counting value sets coincident with an identification code IDn ; and the identification code values IDn are set so as to satisfy the formula IDn+1 >IDn , and the interval is set so as to require counting signals to need a time τ for counting the interval value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to a technical field related to switching of weighting factors (also referred to as weight values) in a code division adaptive array antenna.

[0002]

2. Description of the Related Art An adaptive array antenna adjusts an amplitude and a phase of each of received signals received by a plurality of antenna elements arranged in space to combine the signals so as to direct a beam directed to an antenna in a direction of arrival of a desired signal. Alternatively, the antenna is adapted to a radio wave environment capable of improving the S / N and lowering the transmission power by, for example, directing a null point in the arrival direction of an undesired signal.

The adjustment of the amplitude and phase is performed by multiplying each received signal by a complex multiplier called a weight coefficient or a weight value by a complex multiplier. The weighting factor is obtained by inputting a received signal of each antenna element, a combined signal, or a difference signal (referred to as an error signal) between the combined signal and the reference signal, using an LMS (Least Mean Square) method or an RLS (Recursive Least Square) method. : Recursive least squares) method and sent to each complex multiplier. Then, a weighting factor is calculated again based on the combined signal of the multiplied signal and the received signal of each antenna element at that time, and the same is repeated again by switching to the weighting factor, thereby obtaining an antenna directional beam. In the direction of arrival of the desired signal.

When the antenna directional beam is directed in the direction of arrival of the desired signal, the weighting coefficient is settled to a constant value (referred to as convergence), but approaches a constant value while fluctuating until then. this,
The time from when the operation is started to when it reaches a certain value is called a convergence time.

FIG. 2 is a block diagram showing a configuration of a portion related to the present invention of a conventional adaptive array antenna. Each of the antenna elements 1-n (n
= 1, 2,..., N) are sampled at the same time by the transceiver A / D converters 2-n at a predetermined period and converted into digital signals. 3
After being delayed by -n for a delay time nτ, the signal is sent to each weighting multiplier 4-n. Here, each weight coefficient register 5-
n is multiplied by the weight coefficient from n. The signal multiplied by the weight coefficient is sent to each adder 6-n.

The adder 6-1 adds the signal from the weighting multiplier 4-1 to the initial value. The time required for addition is τ
It is. Therefore, the output signal from the adder 6-1 is obtained by subtracting τ from the sampled signal and the adder 6-
1 results in a signal with a total of 2τ delayed by τ.
Sent to 2.

On the other hand, the adder 6-2 receives 2
Since the signal weighted and multiplied with a delay of τ is input, the signals delayed by 2τ are eventually added, which means that the signals sampled at the same time are added.

Similarly, in the adder 6-n, a signal having a total of nτ delays of the delay (n-1) τ by the preceding (n-1) adders and the delay τ by the delay unit 3-1 is added. , Delay unit 3
The addition of the signal obtained by weighting and multiplying the signal delayed by nτ at −n is performed, and the signals sampled at the same time are added because the signals are delayed by nτ.

Thus, the adders 6-1 to 6-N
The combined signal sequentially added up to is transmitted to the indoor device. As described above, the reception signals from the respective antenna elements are combined by successive addition and then transmitted indoors because the outputs of the weighting multipliers 4-n for the respective antenna elements are separately transmitted indoors. This is because, compared to the case, the number of signal lines to be sent indoors can be reduced to 1 / N.

On the other hand, the weight coefficient register 5
Weight coefficients are sent to −1 to 5-N by a common line. An address is assigned to each weight coefficient register in advance, and the weight coefficient following the address is written in the weight coefficient register of the address specified by the common line.
When the writing of the weighting coefficients into the weighting coefficient registers 5-1 to 5-N is completed, the written weighting coefficients are simultaneously sent to the corresponding weighting multipliers. If the weighting factor has already been sent before that, the weighting factor is switched.

When the weighting coefficient is switched, the signal from each delay unit is again subjected to complex multiplication, and its output is successively added and synthesized by adders 6-1 to 6-N, and the synthesized signal is transmitted to the indoor side. Then, the calculation of the weighting coefficient is performed by a predetermined algorithm, whereby the updating of the weighting coefficient register is repeated, so that the weighting coefficient goes to the convergence value.

[0012]

However, the above-mentioned prior art has the following problem with respect to the timing of switching the weight coefficient to the weight multiplier. That is, in the series of the antenna element 1-1, the sampling reception signal input to the weighting multiplier 4-1 is delayed by the time τ in the delay unit 3-1. 2τ, 3τ for the series of antenna elements 1-3, generally nτ for the series of antenna elements 1-n,
In the last series of antenna elements 1-N, those delayed by Nτ are input to each weighting multiplier. On the other hand, the switching of the weight coefficients is performed simultaneously in N series in real time as described above.

As a result, the signal multiplied by the weighting coefficient by the weighting multiplier is not a signal received simultaneously by each antenna element but is received earlier by τ from antenna element 1-1 to antenna element 1-N sequentially. Signal.

FIG. 3A shows an antenna element 1 as an example.
−1 series sampling holding signals S ₁₁ , S ₁₂ , S ₁₃ and the antenna element 1-2 series sampling signals S ₂₁ , S 12
_22, shows the S _23. That, S ₁₁ and S _21, S ₁₂ and S _22, S ₁₃
And S ₂₃ is a signal sampled at a sampling period Δt at the same time with one another. Before this is input to the weighting multiplier, the delay element 3-
1. When the delay device 3-2 enters the sequence of the antenna element 1-2, as shown in FIG. 3B, the output of the delay device has the output of the antenna element 1-2 in the sequence of the antenna element 1-1. It will be delayed by τ from the series. τ is the sampling period Δ
Since it is an integral multiple of t (twice in FIG. 3B), when looking at signals after passing through each delay unit, all signals at the same time are called signals sampled at different sampling times. Will be.

Originally, each weighted multiplication should be performed on signals received by each antenna element at the same time. However, as shown in FIG. 3B, signals weighted and multiplied at different times are sampled. However, when these are sequentially added, there is a problem that a synthesized signal with low reliability is output.

In view of the above-mentioned problems of the prior art, it is an object of the present invention to convert the antenna element 1-1 into the antenna element 1-1.
Focusing on the fact that the delay of the signal input to each weighting multiplier is increased by τ for each series over the N series, the switching of the weighting factor to the weighting multiplier is also performed by the antenna element 1-1. By performing the delay by τ every time one sequence is advanced from the sequence, all the weighted multiplications are performed on the signals received at the same time by each antenna element, and a highly reliable synthesized signal is output successively. An object of the present invention is to provide an additive type code division adaptive array antenna.

[0017]

In order to achieve the above object, a code division adaptive array antenna according to the present invention has the following configuration. That is, the reception signal from each of the plurality of antenna elements arranged in space is synchronously sampled at a predetermined time interval, and the delay is increased by a predetermined unit delay time τ in the adjacent order from the reference antenna element. Is given, weighting is performed on the amplitude and phase of each signal, and thereafter, a weight is given to each sampling signal in a code division adaptive array antenna in which each signal is sequentially added to a signal corresponding to a reference antenna element in order of adjacentness. Is switched in the order of adjacent time from the reference antenna element to the antenna element corresponding to the signal.
A code division adaptive array antenna, characterized in that the code division adaptive array antenna is provided with a means for increasing the delay in increments.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a successive addition type adaptive array antenna, in which a delay time given to a sampling reception signal input to a weighting multiplier for a series of antenna elements has a unit delay time in accordance with the arrangement order of antenna elements. Focusing on the increase in τ, the switching of the weighting factor in each weighting multiplier is also performed by increasing the delay time by τ in accordance with the arrangement order of the antenna elements, so that each sampling signal at the time of switching the weighting factor is all In the antenna element series, the signals are sampled at the same time.

By sequentially adding the weighted signals thus obtained, a highly reliable synthesized signal can be obtained.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a successive addition type code division adaptive array antenna of the present invention. FIG.
Is different from the weight coefficient registers 5-n (n = 1, 2, 2).
.., N), respectively.
n is provided, and each switching timing device is provided with an identification code ID _n corresponding to the order of each antenna element from one side and a count signal input from a common line via the other side. Note that each identification code may be set in advance in each switching timing device. The count signal is a digital signal of a plurality of parallel bits generated by the count signal generator 8 and counts up from 0 at a constant speed.

For the identification code, a fixed value of a plurality of parallel bits is set. Then, when the count signal matches the identification code, a switching command is issued from the switching timing unit to the weight coefficient register, whereby the weight coefficient to be multiplied by the weight multiplier is switched to a new value.

Here, the relationship between adjacent identification code values is ID
_{n + 1>} has a ID _n, the interval, the time count signal takes to count the interval value is set to just become tau.

[0023] Therefore, now, when the value becomes ID ₁ count signal starting counting from 0, switched to the new value weighting factor to be multiplied by the weighting multiplier 4-1, then the time elapses τ the count signal matches the identification code ID _2, the weight coefficient to be multiplied by the weighting multiplier 4-2 is switched to a new value, hereinafter similarly delayed by time tau, the weighting multiplier 4-3, the 4-4, …
.., The weighting coefficients in 4-N are switched.

By the way, the sampling reception signal input to the weighting multiplier is applied to each of the delay units 3-
In the process of proceeding from the sequence of the antenna element 1-1 to the sequence of the antenna element 1-N, there is a delay of τ every time the sequence advances, so that the switching of the weighting factor is changed by τ every time the channel advances as described above. Delaying means that switching of weighting factors is performed on signals that are simultaneously received by a plurality of antenna elements and sampled at the same time,
As in the conventional case, it is not necessary to output a low-reliability composite signal as in the case where weighting coefficients are switched between signals sampled at different times.

In this embodiment, as means for delaying the switching of the weighting factor by τ as the channel corresponding to each antenna element advances, means (switching timing unit) for issuing a switching instruction when the identification code and the count signal match are provided. However, the present invention is not limited to this, and a means for sequentially inputting an instruction signal at intervals of τ to each weight coefficient register may be used. Further, a counter signal generator may be built in the switching timing device.

The switching operation of the series of weighting coefficients may be started after the weighting coefficients have been written in all the weighting coefficient registers. Should be written, for example, if the writing is performed with a sequential delay of a time shorter than τ, the switching is started after the writing to the first weight coefficient register is completed,
It is also possible to switch sequentially with a delay of τ.

[0027]

As described above, in the successive addition type code division adaptive array antenna according to the present invention, the sampling signal of the reception signal input to the weighting multiplier for each antenna element has a τ according to the arrangement order of the antenna elements. In response to the delay of increasing each time, the switching of the weighting coefficient to the weighting multiplier is also performed with a delay of τ in the same manner. The weighted multiplication has been performed, and the combined signal obtained by sequentially adding them has a higher reliability than the conventional case where the switching of the weighting coefficient is not always performed only on the received signal sampled at the same time. There is an advantage that a synthesized signal having a high degree of noise can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a portion according to the present invention of a successive addition type code division adaptive array antenna.

FIG. 2 is a block diagram showing a configuration of a conventional successive addition type code division adaptive array antenna from an antenna element to a portion that performs successive addition.

FIG. 3 shows that sampling signals input to the weighting multipliers are sequentially delayed by τ in accordance with the arrangement order of the antenna elements, so that the weighting factors are switched at an arbitrary time and the sampling times are not the same. 9 is a timing diagram illustrating that switching of a weight coefficient is performed over a sampling signal.

[Explanation of symbols]

 1-1 to 1-N antenna element 2-1 to 2-N transceiver A / D converter 3-1 to 3-N delay unit 4-1 to 4-N weight multiplier 5-1 to 5-N weight Coefficient register 6-1 to 6-N Adder 7-1 to 7-N Switching timing unit 8 Count signal generator

Claims (1)

[Claims] 1. A unit delay time .tau. That is predetermined for each signal obtained by synchronously sampling reception signals from a plurality of antenna elements arranged in space at predetermined time intervals in the order of adjacent elements from a reference antenna element. After increasing the delay, the amplitude and phase of each signal are weighted, and then each signal is sequentially added to the signal corresponding to the reference antenna element in the code division adaptive array antenna in which the signals are sequentially added in the adjacent order. The switching timing of weighting for the signal
A code division adaptive array antenna, comprising: means for increasing and delaying the antenna element corresponding to the signal by the time τ in order of adjacency from a reference antenna element.