WO2002007257A1 - Nulling method with an antenna array - Google Patents

Nulling method with an antenna array Download PDF

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Publication number
WO2002007257A1
WO2002007257A1 PCT/FR2001/002337 FR0102337W WO0207257A1 WO 2002007257 A1 WO2002007257 A1 WO 2002007257A1 FR 0102337 W FR0102337 W FR 0102337W WO 0207257 A1 WO0207257 A1 WO 0207257A1
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WO
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Prior art keywords
antenna
gain
step
value
associated
Prior art date
Application number
PCT/FR2001/002337
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French (fr)
Inventor
Laurent Herault
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Commissariat A L'energie Atomique
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/2605Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
    • H01Q3/2611Means for null steering; Adaptive interference nulling

Abstract

The invention concerns a nulling method with an antenna array (A1, A2, , AM). Each antenna (Aj) is associated with a phase information and a gain information. The method comprises, for each antenna, a step which consists in a phase quantization step and a gain quantization step enabling to define least significant phase bits and least significant gain bits, and a step which consists in minimizing the total power received by the antenna (A1, A2, , AM) by modifying at least one least significant gain and/or phase bit. The step which consists in minimizing the total power received includes a microcanonical annealing step. The invention is applicable to satellite telecommunications, cellular telephone or wireless local networks.

Description

TRAINING PROCESS OF ZEROS FOR NETWORK ANTENNA

Technical field and prior art

The invention relates to a zero-forming process by an antenna array.

The invention applies, for example, in areas such as satellite communications, cellular or wireless local networks. An antenna array is generally configured to receive from one or more specified coverage areas signals. A zero forming method used to modify the network reception law antenna in phase and / or amplitude in order to place zeros for receiving the signals outside the useful or coverage areas.

Several methods are known to the skilled person for the formation of zeros. The document "Phase-Only Adaptive Nulling wi th a

Genetic Algori thm "Raπdy L. Haupt, IEEE Transactions on Antennas and Propagation, vol. 45, No. 6, June 1997 discloses a method for adjusting the phases of the signals received so as to place several deep nulls in the direction of interference and to minimize disruption of the useful part of the array radiation diagram.

The paper "Experimental Adaptive Nulling wi th a Genetic Algori thm" Randy L. Haupt, H. Southall, Microwave Journal, January 1999, discloses a device for the formation of zeros by adjusting the phases and gains of the antennas.

Both documents relate to zeros forming method of adjusting the signals of the phases and / or gains of the antennas, previously quantized and encoded on a number of bits, so as to minimize the total power output of the network.

In the absence of disturbances, such an approach leads to minimizing the useful signal. To avoid this minimization, the method is implemented only when the ratio of the useful signal on the signal consisting of disturbance and noise is low. Only the least significant bits of the phases and amplitudes are modified. To determine the lower bits that minimize the output power, the processes use a genetic algorithm, ie an algorithm that simulates the laws of genetics. Genetic methods have many disadvantages.

They are an empirical approach which does not ensure, with a limited speed, the asymptotic convergence to optimal solutions. Values ​​should be given to parameters such as the size of the population, the number of generations, the crossover rate, mutation rate, the number of executions needed to obtain good solutions, etc .. A many potential solutions, called individuals, should be retained. The occupied memory size these solutions can become significant, which should be avoided for networks of embedded antennas such as networks used in satellite communications. In addition, to sort the different potential solutions kept in memory, a large number of power measurements is needed.

The invention does not have the disadvantages mentioned above.

Lecture 1 invention

Indeed, the invention concerns a method of forming at least one zero by an antenna array, each antenna being associated with phase information and gain information, the method comprising, for each antenna, a step of quantizing the phase and / or a gain quantization step for defining LSBs phase and low weight gain bits, and the total power minimization step received by the antenna array by changing at least one least significant bit of gain and / or phase, the total power received minimization step using a combinatorial optimization method. The optimization method comprises co binatoire an annealing step Microcanonical.

According to a further feature of the invention, the annealing step comprises an iterative procedure Microcanonical Creutz which comprises randomly selecting an antenna network, randomly selecting at least one bit from the least significant bits phase and / or gain associated with the selected antenna, the inversion of the least significant bit selected and the measurement of the total power received by the antenna array in the thus selected configuration. According to another additional feature of the invention, the implementation step of the procedure Creutz comprises N successive random selections of a "daemon" from D "demons" stored, each "daemon" stored being associated with a value energy, and a value of a test variable that counts the number N of random selections made is increased by one for each selection.

According to another additional feature of the invention, the energy value associated with a daemon is compared with the variation of the power induced by the inversion of the least significant bit so that if said variation is less than 1 energy associated with the daemon, the energy associated with the daemon is corrected and the value of the least significant bit and confirmed, otherwise, a new demon is selected.

According to another additional feature of the invention, the phase information and gain of each antenna is stored if the measured total power is set to a value which is the smallest value measured from the start of the process.

According to another additional feature of the invention, when the number of selections reaches the value N, the energy value associated with each of demons is decreased, the value of the test variable is reset and a new sequence of random selections successive demon is performed. According to another additional feature of the invention, energy values ​​associated with the various "demons" are chosen to be identical.

The method of the invention modifies the phases and / or gains quantified on the basis of the total power measurements received by the antenna array and preferably uses a limited number of phase bits and gain of each antenna.

BRIEF DESCRIPTION OF FIGURES

Other features and advantages of the invention appear on reading a preferred embodiment of the invention described using the accompanying drawings: - Figure 1 shows the zero forming method according to the mode preferred embodiment of the invention,

- Figure 2 shows an apparatus block diagram for implementing the zero forming method according to the invention.

Description of oeuyre in embodiments of one invention

1 shows the zero forming method according to the preferred embodiment 1 of the invention.

The method comprises three main steps: an initialization step; - an implementation stage of the procedure Creutz; an annealing step. The initialization step (step 1) comprises three main basic steps.

As previously mentioned, the gain and the phase shift associated with each antenna are quantified. Thus, a phase shift is it encoded by a P-bit word and a gain by a G-bit word.

A first elementary step of the initialization step consists in defining a number of least significant bits of gain and / or phase that the method will be able to modify. A number N of P bits of low weight of the P bit word is thus selected, and a number N G of low weight of the G-bit word bits.

By way of nonlimiting example, N P and N G can be respectively equal to 3 and 2 to P and G equal to 8.

Cod wedding is the code word associated with modifiable bit. Cod Thus, for example, a vector consisting of the succession of values of the N bits P phase and the N-bit G gain. A second sub step consists in defining the initial values ​​of parameters that will be used in the process according to the invention. Thus, D real numbers, commonly called "demons", associated with respective energies Ec x, Ec 2, ..., D are stored Ec, an integer N, for example N = 100xNpxN G, is defined and stored, a real number belonging to the interval [0, 1 [and close to 1, for example a = 0.96 is set and stored, an integer mem initial value 0 is set is stored, an integer closest to memopt 0, for example memopt = N / 1000, is defined and stored, and an integer of 0 to initially test is defined and stored.

As will appear below, these parameters represent the necessary variables for implementing the method according to one invention.

A third elementary step is to initialize a measure of the total power Pout received by the antenna array. The corresponding Cod codeword is made and stored. Popt a parameter is defined as the minimum measured power output. Cod opt coding corresponding to the parameter Popt is also defined and stored.

The implementation step of the procedure Creutz comprises a moving step (step 2) which comprises the following steps:

- test parameter increment by one unit (test = test

+ 1)

- randomly selecting a network antenna and at least one least significant bit phase and / or at least one least significant bit of gain change,

- reversal or bit (s) selected low weight (s) (bit = 1 - bit)

- measuring the total power Pn of the antenna array with the thus obtained adjustment,

- calculating the power variation .DELTA.P = Pn - Pout.

- random selection of a "demon" of selected from D stored.

If the inversion of the bit or bits (s) mentioned above leads to a power variation of less than Ec (step 3, .DELTA.P <Ec d), the following operations are implemented (step 4):

- storing the new setting in the Cod code word, - the energy value Ec of the "demon" d is corrected to the value .DELTA.P (Ec = Ec d d - .DELTA.P)

- the em parameter is incremented by one (mem = mem + 1).

If Pn <P opt (step 8), while setting the low order bits found is the best and stored (Step 5). It comes Cod Cod and opt = P = P n ot. Steps 8 and 5 are optional.

If the inversion of the bit does not lead to a negative power variation, the setting of low-order bits is stored in the parameter Cod, provided that Pn is less than Ec d, and the following operations are implemented:

- mem parameter is incremented by one (mem = mem + 1), - the energy value Ec of the "daemon" d is corrected to the value .DELTA.P (Ecd: = Ecd - .DELTA.P).

As the number of settings tested in the second step (procedure Creutz) is less than the value N (Step 6), the process returns to the beginning of the procedure Creutz. When the number N is reached, the process proceeds to the annealing step (Step 7). The variable is then reset test (test = 0).

If the number of stored settings (mem setting) during the procedure Creutz is above the limit value memopt, then the following operations are performed (step 7): - mem parameter is reset,

- the values ​​of the energies of the "demons" are decreased, for example by multiplying each by the value - the process returns to the beginning of the procedure Creutz.

If the number of stored settings (mem parameter) during the procedure of Creutz is less than or equal to the limit value memopt (step 9), the process returns to the beginning of the procedure Creutz.

According to a variant of the invention, the initial values of Eci energies, Ec 2, ..., D are chosen to be identical Ec and sufficiently high. It is possible that most encodings tested during the work up of the Creutz procedure are stored.

The annealing step microcanonical has many advantages. The setup process is simple and robust. It follows that the performances are very sensitive to small changes in parameters.

Moreover, it is possible to limit in time the optimization process. So, can the duration of the convergence process be reduced by decreasing or N.

2 shows an apparatus block diagram for implementing the zero forming method according to the invention.

The device comprises an antenna block B, a receiver R, a MP power measurement circuit and a test module T. optimizing the antenna block B comprises an array of M antenna elements Ai, A,. .., A M. The signal from each antenna element j (j = l, 2, ..., M) is corrected: it is out of phase and amplified. Thus, a coded information with a word of P bits-t it represents the antenna phase shift and encoded information by she is G-bit word the gain of the antenna. The word of P bits and the G-bit word are respectively transmitted to a PHJ phase correction circuit and a AGJ gain correction circuit.

The phj phase correction circuit and the gain correction circuit receiving IFG, also Cod codeword from the test module optimization T. The corrected code from the phj phase correction circuit consists of a word whose bits P P N least significant bits have values for the values of N P-bit word Cod. Similarly, the corrected code from the IFG gain correction circuit consists of a G-bit word whose G N least significant bits have values for the values of N G-bit word Cod.

The corrected phase code from the PHJ circuit and the fixed gain code from the AGJ circuit are transmitted to a circuit MDj antenna signal reconstruction.

All the reconstituted signals from different devices MDj (j = l, 2, ..., M) are summed in an adder Σ.

The signal from the summation Σ is transmitted to a receiver R. A power measurement circuit PM receives a signal from the receiver R to measure the power of the signal from the adder Σ. The power information measured after the MP circuit is provided to test module T. optimization

The test module T optimization includes various elements for implementing the method according to 1 the invention for determining the Cod word to apply to the antenna array. It follows that the test module and T optimization includes memory circuits and a computing unit for implementing the procedure of Creutz and microcanonical annealing as described in Figure 1.

Claims

1. A method of forming at least one zero by an array of antennas (Al, A2, ..., AM), each antenna
(Aj) associated with phase information and gain information, the method comprising, for each antenna, a phase quantization step (P) and / or a gain quantization step (G) for defining LSBs phase
(Np) and low gain bits (N G), and a minimization step of the total power (Pn) received by the antenna array by modifying at least one least significant bit of gain and / or phase, the total power received minimization step implementing a combinatorial optimization method, characterized in that the combinatorial optimization method comprises an annealing step microcanonical (2, 3, 4, 5, 6 , 1, 8, 9).
2. Method according to claim 1, characterized in that one annealing step Microcanonical (2, 3, 4, 5, 6, 7, 8, 9) comprises an iterative procedure Creutz (2, 3, 4) which comprises the random selection of an antenna network, randomly selecting at least one bit among the bits (D L, N L) of low stage weight and / or gain associated with the selected antenna, the reversal of least significant bit selected and the measurement of the total power (Pn) received by the antenna array in the thus selected configuration.
3. The method of claim 1 or 2, characterized in that the implementation stage of the procedure Creutz (2) comprises N successive random selections of a "daemon" (d) from D "demons" stored, each "demon" stored being associated with an energy value (x Ec, Ec 2, ..., D Ec), and in that a value of a test variable (test) which counts the number N of random selections made is increased by one unit at each selection.
4. The method of claim 3, characterized in that the energy value associated with a daemon (d) is compared with the variation of the power induced by the inversion of the least significant bit so that if said variation is less than the energy associated with the daemon (d), the energy associated with the daemon (d) is corrected (4) and the value of the least significant bit and confirmed, otherwise, a new demon (d) is selected.
5. A method according to claim 4, characterized in that the phase information and gain of each antenna is stored (5) if the measured total power is set to a value which is the smallest value measured from the start of the process.
6. A method according to any one of claims 3 to 5, characterized in that, when the number of selections reaches the value N, the energy value associated with each of demons (d) is decreased, the value of the variable test (test) is reset and a new sequence of successive random selections of a demon (d) is performed.
7. A method according to any one of claims 3 to 6, characterized in that the energy values (Eci, Ec 2, ..., Ec D) associated with the various "demons" are chosen to be identical.
PCT/FR2001/002337 2000-07-19 2001-07-18 Nulling method with an antenna array WO2002007257A1 (en)

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FR00/09466 2000-07-19
FR0009466A FR2812127A1 (en) 2000-07-19 2000-07-19 zeros formation method by a network of antennas

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9379439B2 (en) 2014-02-14 2016-06-28 The Boeing Company Adaptive interference suppression via subband power measurements of a phased-array antenna
US9490893B2 (en) 2013-09-26 2016-11-08 The Boeing Company Interference suppression in a satellite communication system using onboard beamforming and ground-based processing

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5963584A (en) * 1996-11-29 1999-10-05 Commissariat A L'energie Atomique Direct sequence spread spectrum transmission process, with generation and optimization of sequences

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5963584A (en) * 1996-11-29 1999-10-05 Commissariat A L'energie Atomique Direct sequence spread spectrum transmission process, with generation and optimization of sequences

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
ARES-PENA F J ET AL: "GENETIC ALGORITHMS IN THE DESIGN AND OPTIMIZATION OF ANTENNA ARRAY PATTERNS", IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION,US,IEEE INC. NEW YORK, vol. 47, no. 3, March 1999 (1999-03-01), pages 506 - 510, XP000830211, ISSN: 0018-926X *
HAUPT R ET AL: "EXPERIMENTAL ADAPTIVE NULLING WITH A GENETIC ALGORITHM", MICROWAVE JOURNAL,HORIZON HOUSE. DEDHAM,US, vol. 42, no. 1, January 1999 (1999-01-01), pages 78,81 - 82,84,87,89, XP000902504, ISSN: 0192-6225 *
HAUPT R L: "PHASE-ONLY ADAPTIVE NULLING WITH A GENETIC ALGORITHM", IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION,US,IEEE INC. NEW YORK, vol. 45, no. 6, 1 June 1997 (1997-06-01), pages 1009 - 1015, XP000655321, ISSN: 0018-926X *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9490893B2 (en) 2013-09-26 2016-11-08 The Boeing Company Interference suppression in a satellite communication system using onboard beamforming and ground-based processing
US9379439B2 (en) 2014-02-14 2016-06-28 The Boeing Company Adaptive interference suppression via subband power measurements of a phased-array antenna

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