DESC:TECHNICAL FIELD
The present disclosure relates generally to wireless communication systems. More particularly, the present disclosure relates to a method and system for determining one or more direction of arrivals (DOAs) for a receiver.
BACKGROUND
The information in this section merely provides background information related to the present disclosure and may not constitute prior art(s) for the present disclosure.
Direction of arrival (DOA) estimation is an essential requirement of many applications of various domains. Estimation of an angle of arrival of a plane wave is known as direction finding or the DOA estimation or determination. Receive beam forming techniques are widely used in the DOA estimation. In most approaches, a receive beam forming is independent of the received signal. In the said approaches, a field of view of antennas is divided into a number of directions, and weights for predefined angles are calculated prior to the signal processing. Further, some existing approaches related to the receive beam forming use received data cues, deployment environment understanding, and calculation of the weights depending on an incident signal to gain improved resolution and improved interference avoidance. However, in some cases of incomplete dependency, the performance of the beam forming techniques is degraded.
Receive beam-forming techniques use an array of antenna elements to receive signals from a specified direction, which can be understood as a spatial filter to a particular direction. In the beam-forming techniques, weights that correspond to filter coefficients for the received signals are matched to the particular direction for forming the beams, which enables a signal processing module to calculate the DOA. A large number of implementations for the DOA estimation using the beam-forming techniques require a number of receiver channels equal to a number of antennas elements.
In the receive beam-forming techniques, the received signals from the array of antenna elements are linearly combined with a weight vector or the spatial filter. In effect, the signals from the particular direction remain in output with significant strength, while signals from other directions are attenuated.
A receive beam forming setup in the receive beam-forming techniques use a set of weights or the filter coefficients for a particular direction of the received signals for the DOA estimation. Hence if an interested field of view is wide, then the set of weights increases. Further, angle resolutions associated with the DOA estimation decide the number of channels to receive from the antennas and the spacing between the antennas to be used. Particularly, the DOA estimation depends on the field of interest, a desired angle resolution, and an antenna array field of view. Furthermore, hardware and computation requirements for the DOA estimation are proportional to the resolution of the angle that is to be measured and a field of view coverage. Hence, the hardware requirement and computation complexity may increase if the desired resolution is large, and the field of view coverage of the antenna is wide.
Some of the receive beam forming techniques are discussed in the forthcoming paragraphs.
One such beam forming technique disclosesdevices and methods for directionally receiving acoustic waves or radio waves for use in applications such as wireless communications systems or radar. The said technique discloses that high directional gain and spatial selectivity are achieved while employing a small array of receiving antennas, especially in the case of spatially oversampled arrays. The method further includes an analysis of frequency, multi-dimensional spectrum analysis, and one-dimensional frequency spectrum analysis.
Another existing technique or method discloses an apparatus and a method for a joint channel and the DOA estimation. Such an existing method is simplified to efficiently estimate channel impulse response associated with a spatially selective transmission channel occurring in a mobile radio channel. Further, the method discloses that to uniformly process all directions, angles associated with a beam are predetermined according to a preset method. This selection calculates a linear system model with a regular spatial sampling using regular spatial separation of beam angles. The method compensates for a difference between an adaptive array antenna and a sector-type antenna using appropriate beam steering according to the calculated linear system model, thereby improving performance and facilitating implementation.
Further, another existing technique discloses a beam-forming system that can be used for both receiving and transmitting beam-forming. The said beam-forming system receives samples of a number of signals, each sample containing a band of frequencies, and routes all sampled signals associated with the same beam-formed frequency band to a predetermined processing block. A predetermined number of the routed sampled signals are selected sequentially according to predetermined criteria, weighted, and accumulated to form a composite signal. Individual signals are then selected from the composite signal and routed to an appropriate output. The beam-forming system uses a much smaller number of weights. The said system reduces the complexity of beam-forming processing substantially and simplifies frequency reuse. In addition, a single digital signal processor (DSP) design that works for both transmitting and receiving the beamforming can be implemented.
Furthermore, yet another existing technique discloses a method for beamforming in a communication system. The method includes receiving a first plurality of training data units via a plurality of antennas. Further, the method includes applying a different steering vector as each training data unit is received. Furthermore, the method includes generating a first plurality of quality indicators based on the first plurality of received training data units, such that each of the first plurality of quality indicators corresponds to a respective one of the first plurality of received training data units. Moreover, the method includes selecting a steering vector based on the different steering vectors and the first plurality of quality indicators.
The above-disclosed prior arts disclose methods that suffer from estimating the DOA in a single stage where computation complexity increases when the number of beams increases, and resolution remains unchanged.
Therefore, there is a need for an alternative solution that may overcome above above-discussed limitations.
The drawbacks/difficulties/disadvantages/limitations of the conventional techniques explained in the background section are just for exemplary purposes and the disclosure would never limit its scope only such limitations. A person skilled in the art would understand that this disclosure and below mentioned description may also solve other problems or overcome the other drawbacks/disadvantages.
BRIEF DESCRIPTION OF THE FIGURES
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Figure 1illustrates a schematic block diagram of an environment including a system for determining one or more direction of arrivals (DOAs) for a receiver, in accordance with an embodiment of the present disclosure;
Figure 2 illustrates a flowchart depicting a methodfor determining the one or more DOAs for the receiver, in accordance with an embodiment of the present disclosure;
Figure 3 illustrates a flowchart depicting a method for estimating one or more coarse DOAs, in accordance with an embodiment of the present disclosure;
Figure 4 illustrates an exemplary plot depicting a transformed magnitude spectrum corresponding to a plurality of RF signals, in accordance with an embodiment of the present disclosure;
Figure 5 illustrates a scalar representation of a coarse resolution and a fine resolution, in accordance with an embodiment of the present disclosure;
Figure 6 illustrates a flowchart depicting a method for estimating a fine DOA for each of the one or more coarse DOAs, in accordance with an embodiment of the present disclosure;
Figure 7 illustrates an exemplary plot depicting a transformed magnitude spectrum corresponding to a set of RF signals among the plurality of RF signals, in accordance with an embodiment of the present disclosure; and
Figure 8 illustrates a schematic block diagram depicting workflow for determining the one or more DOAs for the receiver, in accordance with an embodiment of the present disclosure.
Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help improve understanding of aspects of the present invention. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
DETAILED DESCRIPTION OF THE FIGURES
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the various embodiments, and specific language will be used to describe the same. It should be understood at the outset that although illustrative implementations of the embodiments of the present disclosure are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present disclosure is not necessarily limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary design and implementation illustrated and described herein, but may be modified within the scope of the present disclosure.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.
Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
It is to be understood that as used herein, terms such as, “includes,” “comprises,” “has,” etc. are intended to mean that the one or more features or elements listed are within the element being defined, but the element is not necessarily limited to the listed features and elements, and that additional features and elements may be within the meaning of the element being defined. In contrast, terms such as, “consisting of” are intended to exclude features and elements that have not been listed.
The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
As is traditional in the field, embodiments may be described and illustrated in terms of blocks that carry out a described function or functions. These blocks, which may be referred to herein as units or modules or the like, are physically implemented by analog or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, or the like, and may optionally be driven by firmware and software. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware, by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the invention. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the invention.
The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents, and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
Figure 1 illustrates a schematic block diagram of an environment 1000 including a system 100 for determining one or more direction of arrivals (DOAs) for a receiver, in accordance with an embodiment of the present disclosure. In an embodiment, the receiver may be configured to receive a plurality of radio-frequency (RF) signals from a transmitter150 and process the received RF signals. In an embodiment, the system 100 may be connected to the receiver. In an embodiment, the system 100 may be a part of the receiver. Accordingly, the system 100 may include a predefined number of antenna elements 102 that may be adapted to receive the plurality of radio-frequency (RF) signals from the transmitter 150.
In an embodiment, the predefined number of antenna elements 102 may be arranged in a predefined configuration. More specifically, the predefined number of antenna elements 102 may be arranged in a predefined configuration, such as a linear topology. In an embodiment, each of the predefined number of antenna elements may receive one RF signal among the plurality of RF signals. In an embodiment, the plurality of RF signals that are received using the predefined number of antenna elements 102 via paths termed as receive channels or channels within the scope of the present disclosure. In an exemplary embodiment, the predefined number of antenna elements 102 is “N” in number. Therefore, a number of channels are equivalent to the predefined number of antenna elements 102 i.e., the predefined number of antenna elements 102 receives the plurality of RF signals via N channels. For example, 32 antenna elements receive the plurality of RF signals using 32 channels.
In an embodiment, the system 100 may further include at least one processor 106 alternatively termed as a processor 106 within the scope of the present disclosure. In an embodiment, the processor 106 may be in communication with the predefined number of antenna elements 102 to receive the plurality of RF signals using N number of channels. In an embodiment, the communication may be wired or wireless communication. In an embodiment, the processor 106 may be configured to process the received plurality of RF signals in multi-stages, specifically in two stages, a coarse stage and a fine stage. In an embodiment, the coarse stage may indicate an initial phase for determining the one or more DOAs for the receiver. Further, the fine stage may indicate a phase subsequent to the coarse stage for determining the one or more DOAs for the receiver.
As a non-limiting example, the processor 106 may be a single processing unit or a set of units each including multiple computing units. The processor 106 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions (computer-readable instructions) stored in the memory 108. Among other capabilities, the processor 106 may be configured to fetch and execute computer-readable instructions and data stored in the memory 108. The processor 106 includes one or a plurality of processors. The plurality of processors is further implemented as a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit, such as a graphics processing unit (GPU), a visual processing unit (VPU), and/or an AI-dedicated processor such as a neural processing unit (NPU). The plurality of processors controls the processing of the input data in accordance with a predefined operating rule or an artificial intelligence (AI) model stored in the memory 108. The predefined operating rule or the AI model is provided through training or learning.
The processor 106 may be disposed in communication with one or more input/output (I/O) devices via Input/Output (I/O) interface 112. The I/O interface 112 employs communication code-division multiple access (CDMA), high-speed packet access (HSPA+), global system for mobile communications (GSM), long-term evolution (LTE), WiMax, and the like, etc. In another embodiment of the present invention, the I/O interface 112 employs ethernet, industrial wireless Local Area Network (LAN), Process Field Bus (PROFIBUS), Actuator Sensor (AS) Interface, and the like. In an embodiment, the I/O interface 112 may be used for electronic warfare (Electronic Support Measure (ESM)) system interface.
In an embodiment, the processor 106 may be implemented at a User Equipment (UE). In a non-limiting example, the UE may be a smartphone, a laptop computer, a desktop computer, a Personal Computer (PC), a notebook, a tablet, or a smartwatch. In another embodiment, the processor 106 may be implemented at a cloud server.
In an embodiment, the system 100 may include a memory 108 in communication with the processor 106. The memory 108 includes a database 110 to store the captured data. In one embodiment, the memory 108 is configured to store instructions executable by the processor 106. In one embodiment, the memory 108 communicates via a bus within the system 100. The memory 108 includes but is not limited to, a non-transitory computer-readable storage media, such as various types of volatile and non-volatile storage media including, but not limited to, random access memory, read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, flash memory, magnetic tape or disk, optical media and the like. In one example, the memory includes a cache or random-access memory (RAM) for the processor 106. In alternative examples, the memory 108 is separate from the processor 106 such as a cache memory of a processor, the system memory, or other memory. The memory 108 is an external storage device or the memory 108 is for storing data. The memory 108 is operable to store instructions executable by the processor 106. The functions, acts, or tasks illustrated in the figures or described are performed by the programmed processor for executing the instructions stored in the memory 108. The functions, acts, or tasks are independent of the particular type of instruction set, storage media, processor, or processing strategy and may be performed by software, hardware, integrated circuits, firmware, micro-code, and the like, operating alone or in combination. Likewise, processing strategies include multiprocessing, multitasking, parallel processing, and the like.
Now, the present disclosure is explained in detail in reference to a method 200 disclosed in Figure 2. More specifically, referring to Figures 1-6in combination, the various steps of the method 200 as described hereinafter may be executed in the system 100, or specifically in the processor 106 of the system 100, for determining one or more DOAs for the receiver.
Figure 2 illustrates a flowchart depicting the method 200 for determining the one or more DOAs for the receiver, in accordance with an embodiment of the present disclosure. The method 200 may alternatively be termed as a receive beam forming method within the scope of the present disclosure. At step 202, the method 200 may include receiving the plurality of RF signals. In an embodiment, the plurality of RF signals may be received using the predefined number of antenna elements 102. In an embodiment, adjacent antenna elements from amongst the predefined number of antenna elements 102 are spaced apart by a first predefined distance (d1). For example, the first predefined distance (d1) is fixed at 0.6 times a wavelength (?1) of a centre frequency of a received bandwidth of the coarse stage.
In an embodiment, each of the predefined number of antenna elements 102 may have a field of view (FOV). In an embodiment, the FOV of the predefined number of elements may be divided into a number of different angles alternatively termed as a plurality of first FOV angles. In an exemplary scenario, a number of the plurality of first FOV angles is represented as “M”. In an embodiment, the plurality of first FOV angles may have a coarse resolution (alternatively termed as coarse stage resolution) which is represented using an equation (1) as below:
Coarse resolution=FOV/M…………..(1)
Further, at step 204, the method 200 may include computing a first weight matrix corresponding to the predefined number of antenna elements 102 and the plurality of first field of view (FOV) angles corresponding to the predefined number of antenna elements 102.
In an exemplary embodiment, the first weight matrix may be computed for the “N” plurality of RF signals and “M” plurality of first FOV angles making a matrix dimension shown using equation (2) below:
N x M ……………………(2)
In an embodiment, the first weight matrix may be computed based on a plurality of first predefined parameters. In an embodiment, the plurality of first predefined parameters may include a wavelength (?1) of a center frequency corresponding to the plurality of the RF signals Further, the first predefined parameters may include an angle number (m) with a step size of the coarse resolution (alternatively termed as coarse stage resolution) corresponding to the plurality of first FOV angles. Furthermore, the first predefined parameters may include the first predefined distance (d1) between the adjacent antenna elements from amongst the predefined number of antenna elements 102.
Accordingly, in an embodiment, the first weight matrix may be computed using equation (3) as shown below:
W_(n,l)=e^(j*(n-1)*?_l )…………….(3)
Where n=0 to N/2-1
?_l=(2*pi*d_1*sin(l))/?_1
Where j =sqrt(-1);
where ?1=wavelength of centre frequency;
l= angle number with step size of a coarse resolution; and
d1=first predefined distance between adjacent antenna elements (0.6*?)
In an embodiment, ?1, l, d1 represent the plurality of first predefined parameters.
Further, at step 206, the method 200 may include estimating one or more coarse direction of arrivals (DOAs) corresponding to the plurality of received RF signals based on the first weight matrix. In an embodiment, the step of estimation of the one or more coarse DOAs is explained and discussed in conjunction with Figure 3.
Figure 3 illustrates a flowchart depicting a method300 for estimation the one or more coarse DOAs, in accordance with an embodiment of the present disclosure. At sub-step 302, the step 206 may include obtaining a first correlated matrix by correlating each of the plurality of RF signals with a corresponding first weight in the first weight matrix.
In an embodiment, the data (the plurality of RF signals) received from the predefined number antenna elements is multiplied with weight matrix (N x M) making a result matrix (first correlated matrix) of 32xM dimension. More specifically, the correlation of the plurality of RF signals with the first weight matrix is done by multiplying a signal vector corresponding to each of the plurality of RF signals with the corresponding first weight in the first weight matrix, thereby obtaining the first correlated matrix.
Further, at sub-step 304, the step 206 may include determining a first Fast Fourier Transform (FFT) for each of the plurality of first FOV angles based on the first correlated matrix. In an exemplary scenario, 32 FFT is calculated on all ‘M’ paths from the “32xM” result matrix (the first correlated matrix).
Furthermore, at sub-step 306, the step 206 may include generating a plot 400 corresponding to the plurality of first FOV angles using the determined first FFT, as shown in Figure 4. The plot 400 is generated using conventional plot generating techniques. Figure 4 illustrates the plot 400 depicting a transformed magnitude spectrum corresponding to a plurality of RF signals, in accordance with an embodiment of the present disclosure. Referring to Figure 4, the generated plot400may depict a transformed magnitude spectrum with a horizontal axis and a vertical axis. In an exemplary embodiment, the horizontal axis corresponds to indices in a range from 1-32. In particular, the plot 400 is generated considering M. Further, the vertical axis corresponds to the magnitude of frequency components corresponding to the plurality of first RF signals.

Then, at sub-step 308, the step 206 may include estimating the one or more coarse DOAs based on the generated plot and using a predefined threshold value. In an embodiment, the indices in the generated plot 400 may be mapped to the plurality of first FOV angles using a predefined mapping technique. For example:
Index : 1, 2,..., 31, 32
FOV angle : 16°, 15°,... ,-14°, -15°.
Further, the magnitude peak values associated with the plurality of RF signals, in the generated plot 400 may be compared with the predefined threshold value. In an embodiment, the predefined threshold value may herein to a threshold magnitude value. For example, the predefined threshold value is 4000, then the processor 106 may select one or more peak values 402 and 404that may be higher than the predefined threshold value, i.e., is 4000. Therefore, in this manner, the indices corresponding to the selected one or more peak values 402 and 404 may be identified to estimate the one or more coarse DOAs (alternatively termed as coarse angles) corresponding to the plurality of RF signals. More specifically, the indices corresponding to the one or more peak values 402 and 404 are mapped to one or more FOV angles among the plurality of first FOV angles, which are estimated as the one or more coarse DOAs. In an exemplary scenario, a maximum amplitude (maximum magnitude) of each path’s FFT across the plurality of first FOV angles is of dimension 1xM as illustrated in Figure 4.More specifically, for example, in case there are ‘M’ number of FFTs ,and thereafter taking maximum of each FFT output, there are ‘M’ maximum numbers., in this manner the plot 400 is generated as plot 1,2,..., M maximums as illustrated in Figure 4.
In an embodiment, the estimated one or more coarse DOAs may be utilized to select second weights for the fine stage, among a plurality of predefined second weights which may be prestored in the memory 108.
Again, referring to Figure 2, at step 208, the method 200 may include computing a second weight matrix. In an embodiment, the second weight matrix may be computed corresponding to a set of alternate antenna elements 104 among the predefined number of antenna elements 102 and a plurality of second FOV angles corresponding to the set of alternate antenna elements 104. In another embodiment, the second weight matrix may be computed prior to the estimation of the one or more coarse DOAs. In an exemplary scenario, the number of the set of alternate antenna elements 104 may be half of the predefined number of antenna elements 102, for example, the set of alternate elements is N/2. In an embodiment, the set of alternate elements may be arranged in the predefined configuration and adjacent alternate elements from amongst the set of the alternate antenna elements may be spaced apart by a second predefined distance(d2). For example, the second predefined distance (d2) is fixed at 1.2 times a wavelength (?2) of a centre frequency of received bandwidth for the fine stage.
In an embodiment, the second weight matrix may be computed based on the plurality of second predefined parameters. In an embodiment, the plurality of second predefined parameters may include the wavelength (?2) of the center frequency corresponding to the set of RF signals received using the set of alternate antenna elements 104. Further, the second predefined parameters may include an angle number (m) with a step size of a fine resolution (alternatively termed as fine stage resolution) corresponding to the plurality of second FOV angles. Furthermore, the plurality of second predefined parameters may include the second predefined distance (d2) between the adjacent alternate antenna elements from amongst the set of alternate antenna elements 104.
In an embodiment, the FOVs of the set of alternate antenna elements 104 may be divided into ‘3*M’ different angles which may be referred to as the plurality of second FOV angles. In an embodiment, the fine resolution may be calculated using equation (4) as below:
Fine resolution =FOV/(3*M)…………………(4)
For example, where FOV/M =coarse resolution,
Fine resolution is (1/3)°
In an embodiment, the fine resolution and the coarse resolution is discussed in conjunction with Figure 5. Figure 5 illustrates a scalar representation of the coarse resolution and the fine resolution, in accordance with an embodiment of the present disclosure. In an embodiment, a first space 504 between vertical lines 502 represent the coarse resolution. Accordingly, 32 first space 504 are illustrated, which represent that the plurality of first FOV angles corresponding to the predefined number of antenna elements 102 are having 32 values. For example, in a case when the coarse resolution is 1o, the values of the plurality of first FOV angles may be considered as -15o, -14o,..,15 o, 16 o. Further, a second space 508 between vertical lines 506 represents the fine resolution. Similarly, the fine resolution is (1/3)°, then the plurality of second FOV angles are (-15+0.333)°, (-15+0.6666)°,.....,(16-0.666)°, (16-0.3333), and 16° as illustrated in Figure 5. For example, the number of the second FOV angles = 96 i.e., (3*M angles).
Now, the second weight matrix corresponding to the set of alternate antenna elements 104 (that are N/2 in number) for the fine stage may computed for the plurality of second FOV angles with the fine resolution of ( FOV)/(3*M). The second weight matrix may be computed using equation (5) as below:
W_(n,m)=e^(j*(n-1)*?_m )……….(5)
where n=0 N/2-1
?_m=(2*pi*d_2*sin(m))/?_2
j corresponds to sqrt(-1)
In an embodiment, the second weight matrix of size (N/2xM) is selected around the estimated one or more DOAs. In an exemplary scenario, the fine stage may use a receive beam-forming technique for the ‘M’ number of FOV angles separated by the fine resolution.
Again, referring to Figure 2, at step 210, the method 200 may include estimating the fine DOA corresponding to each of the estimated one or more coarse DOAs based on the second weight matrix. For example, if the estimated coarse DOAs (coarse angles) are -5°and +3°, then the fine DOA may be estimated for each coarse DOA i.e. for both -5°and +3°.In an embodiment, the estimation of the fine DOA may be explained and discussed in conjunction with Figure 6.
Figure 6 illustrates a flowchart depicting a method for estimating the fine DOA for each of the one or more coarse DOAs, in accordance with an embodiment of the present disclosure. At sub-step 602, the step 210 may include obtaining a second correlated matrix by correlating each of a set of RF signals among the plurality of RF signals with the corresponding second weight in the second weight matrix. In an embodiment, the data (set of RF signals) received from the set of alternate antenna elements 104channels is multiplied with weight matrix ((N/2) x M) making a result matrix (second correlated matrix) of 32xM dimension. More specifically, the correlation of the set of RF signals with the second weight matrix is done by multiplying a signal vector corresponding to each of the set of RF signals with the corresponding second weight in the second weight matrix, thereby obtaining the second correlated matrix.
Further, at sub-step 604, the step 210 may include determining a second FFT for each of the plurality of second FOV angles based on the second correlated matrix. In an embodiment, one 32-point FFT is calculated on all ‘M’ paths from 32xM result matrix (the second correlated matrix). In an exemplary scenario, a maximum amplitude (maximum magnitude) of each path’s FFT across the plurality of second FOV angles is of dimension 1xM as illustrated in Figure 7. More specifically, one 32-point FFT gives 32-point output, in this case, the maximum number of this 32-point FFT output, 1 number is obtained. Further, there are ‘M’ FFTs and therefore ‘M’ FFT maximums, thereby providing 1,2,....,M results.
Further, at sub-step 606, the step 210 may include generating a plot 700 corresponding to the plurality of second FOV angles using the determined second FFT. Referring to Figure 7, the generated plot 700 may depict a transformed magnitude spectrum with a horizontal axis and a vertical axis. In an embodiment, the horizontal axis corresponds to indices in a range from 1-32. Further, the vertical axis corresponds to the magnitude of frequency components corresponding to the set of RF signals.
Furthermore, at sub-step 608, the step 210 may include estimating the fine DOA based on the generated plot 700 using the predefined threshold value, for example, the predefined threshold value is 4000. In the generated plot 700, magnitude peak values associated with the set of RF signals may be compared with the predefined threshold value. In an embodiment, the processor 106 may select one or more peak values 702 and 704 that may be higher than the predefined threshold value. Therefore, in this manner, an index corresponding to the said one or more peak values may be compared with the estimated coarse DOA to estimate the fine DOA (alternatively termed as a fine angle) for each of the one or more coarse DOAs. More specifically, the indices corresponding to the one or more peak values 702 and 704 are mapped to a corresponding FOV angle among the plurality of second FOV angles. Thereafter, the mapped angle values are compared with the estimated coarse DOA to estimate the fine DOA for the said estimated coarse DOA. An exemplary scenario, for estimation of the fine DOA for each of the one or more coarse DOAs is discussed in forthcoming paragraphs.
In an exemplary scenario, the coarse DOAs are estimated as -5°and +3°. In an embodiment, the fine resolution weights of “M” number or the second FOV angles (M=32 second FOV angles) are obtained based on the fine resolution which is 0.3333. In an embodiment, the estimation of the fine DOA for the estimated coarse DOA (-5°) corresponds to a first pass (1st pass) of the fine stage.
The second FOV angles obtained are (-5-(15*0.3333))o, (-5-(14*0.3333))o, ...., (-5-(15*0.3333))o, (-5 +(16*0.3333))o, separated by the fine resolution of 0.3333. Further, the indices1-32 get mapped to the plurality of second FOV angles using the predefined mapping technique.
Index : 1, 2,.. , 31 ,32
Fine angle: -5+(16*0.333))°, -5+(15*0.333))°,..., -5-(14*0.333))°, -5-(15*0.3333))°
In an embodiment, one or more fine angles among the plurality of second FOV angles are identified based on the mapping. For example,15thindex, and 27th index peaks values 702 and 704 are identified as higher than the predefined threshold value, and corresponding mapped angle values (one or more fine angles) are (-5 +(2*0.333)) = -4.334o and (-5-(10*0.333)) = -8.333oare identified respectively as illustrated in Figure 7.
The one or more fine angles in the fine stage are compared with the estimated coarse DOA (for example, -5°), and a nearest or a proximate angle is identified corresponding to the estimated coarse DOA, which is considered as the estimated fine DOA (fine angle) for the 1st pass of the fine stage. In a present example scenario, -4.334° is considered as the estimated fine DOA or a fine resolution output of the 1st pass for the fine stage.
In an embodiment, the estimation of the fine DOA for the estimated coarse DOA (+3°) corresponds to a second pass (2nd pass) of the fine stage.
Similarly, the fine DOA is estimated for the coarse DOA (coarse angle), +3°. The second FOV angles obtained are (+3 - (15*0.3333)) o, (+3 -(14*0.3333))o,..., (+3 -(15*0.3333)) o, (+3 +(16*0.3333)) o, separated by the fine resolution of 0.3333. Further, the indexes 1-32 get mapped to the plurality of second FOV angles using the predefined mapping technique as shown below.
Index : 1, 2,.. , 31 ,32
Fine angle: +3+(16*0.333))°, +3+(15*0.333))°,..., +3-(14*0.333))°, +3-(15*0.3333))°
Therefore, the one or more fine angles for the coarse angle (+3°)are identified based on the mapping to estimate the fine DOA for the coarse angle ((+3°).
Again, referring to Figure 2, at step 210, the method 200 may include determining the one or more DOAs for the receiver based on the estimated fine DOA for each of the one or more coarse DOAs. For example, the fine resolution outputs or the fine angles estimated at different passes, for example, 1stpass and 2nd pass are considered as the one or more DOAs for the receiver.
Figure 8 illustrates a schematic block diagram 800 depicting a workflow of the system 100, in accordance with an embodiment of the present disclosure.
In an embodiment, block 810 corresponds to the coarse stage. Accordingly, at block 802, the processor 106 may be configured to receive the plurality of the RF signals received using the predefined number of antenna elements 102 (via N channels) and compute the first weight matrix. Further, at block 804, the processor 106 may be configured to determine the first FFT for each of the plurality of first FOV angles. Further, at block 806, the processor 106 may be configured to estimate the one or more coarse DOAs using the determined first FFT. Further, at block 808, the processor 106 may be configured to estimate the one or more coarse DOAs using the determined first FFT. At block 808, the processor 106 may be configured to select second weights for the fine stage based on the estimated one or more coarse DOAs. In an embodiment, the second weights may be received or selected from the memory 108.
Further, block 820 corresponds to the fine stage. Accordingly, at block 802, the processor 106 may be configured to receive the set of RF singles received using the set of alternate antenna elements 104 (via N/2 channels) and compute the second weight matrix. In another embodiment, the second weight matrix may be computed prior to the estimation of the one or more coarse DOAs. Further, at block 824, the processor 106 may be configured to determine the second FFT for each of the plurality of second FOV angles. Further, at block 826, the processor 106 may be configured to determine the one or more fine angles among the second FOV angles using the determined second FFT. Further, at block 828, the processor 106 may be configured to estimate the fine DOA for the coarse DOA based on comparing the one or more fine angles with the coarse DOA. Furthermore, at block 830, the fine DOAs estimated for the coarse DOAs may be determined as the one or more DOAs for the receiver.
In various embodiments, at block 832, the memory 108 may be adapted to store a plurality of predefined first weights and the plurality of predefined second weights corresponding to the coarse stage and the fine stage respectively.
In an embodiment, the workflow of the system 100 is already discussed in conjunction with Figures 2-7. Hence, the same has not been discussed herein in detail for the sake of brevity.
Now, the advantages of the present disclosure are discussed. The present disclosure uses multiple stages (coarse stage and fine stage) of multiple resolution of beam forming weights to reduce hardware occupancy. The present disclosure improves performance of the beam performing method. The present direction utilize estimated the one or more coarse DOAs and the estimated fine DOA for each of the one or more coarse DOAs for estimation of the one or more DOAs for receiver with a better accuracy.
The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements can be at least one of a hardware device or a combination of hardware devices and software modules.
It is understood that terms including “unit” or “module” at the end may refer to the unit for processing at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software.
While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.
The drawings and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein.
Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims.
Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any component(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or component of any or all the claims.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of at least one embodiment, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
,CLAIMS:1. A method (200) for determining one or more direction of arrivals (DOAs) for a receiver, the method (200) comprising:
receiving a plurality of radio-frequency (RF) signals using a predefined number of antenna elements (102);
computing a first weight matrix corresponding to the predefined number of antenna elements (102) and a plurality of first field of view (FOV) angles corresponding to the predefined number of antenna elements (102) based on a plurality of first predefined parameters;
estimating one or more coarse direction of arrivals (DOAs) corresponding to the plurality of received RF signals based on the first weight matrix;
computing a second weight matrix corresponding to a set of alternate antenna elements (104) among the predefined number of antenna elements (102)and a plurality of second FOV angles corresponding to the set of alternate antenna elements (104) based on a plurality of second predefined parameters;
estimating a fine DOA corresponding to each of the one or more coarse DOAs based on the second weight matrix; and
determining the one or more DOAs for the receiver based on the estimated fine DOA.
2. The method (200) as claimed in claim 1, wherein estimating the one or more coarse DOAs comprises:
obtaining a first correlated matrix based on correlating each of the plurality of RF signals with a corresponding first weight in the first weight matrix;
determining a first Fast Fourier Transform (FFT) for each of the plurality of first FOV angles based on the first correlated matrix;
generating a plot corresponding to the plurality of first FOV angles using the determined first FFT; and
estimating the one or more coarse DOAs based on the generated plot and using a predefined threshold value.
3. The method (200) as claimed in claim 1, wherein estimating the fine DOA corresponding to each of the one or more coarse DOAs comprises:
obtaining a second correlated matrix by correlating each of a set of RF signals among the plurality of RF signals with a corresponding second weight in the second weight matrix, wherein the set of RF signals are received using the set of alternate antenna elements (104);
determining a second FFT for each of the plurality of second FOV angles based on the second correlated matrix;
generating a plot corresponding to the plurality of second FOV angles using the determined second FFT; and
estimating the fine DOA based on the generated plot using the predefined threshold value.
4. The method (200) as claimed in claim 1, wherein the predefined number of antenna elements (102) are arranged in a predefined configuration, and wherein adjacent antenna elements from amongst the predefined number of antenna elements (102) are spaced apart by a first predefined distance (d1).
5. The method (200) as claimed in claim 1, wherein the set of alternate antenna elements (104) are arranged in the predefined configuration, and wherein adjacent alternate antenna elements from amongst the set of alternate antenna elements (104) are spaced apart by a second predefined distance (d2).
6. The method (200) as claimed in claim 1, wherein the plurality of first predefined parameters comprise at least one of:
a wavelength (?1) of a center frequency corresponding to the plurality of RF signals,
an angle number (l) with step size of a coarse resolution corresponding to the plurality of first FOV angles; and
the first predefined distance (d1) between the adjacent antenna elements from amongst the predefined number of antenna elements (102).
7. The method (200) as claimed in claim 1, wherein the plurality of second predefined parameters comprise at least one of:
a wavelength (?2) of a center frequency corresponding to the set of RF signals received using the set of alternate antenna elements (104);
an angle number (m) with a step size of a fine resolution corresponding to the plurality of second FOV angles; and
the second predefined distance (d2) between the adjacent alternate antenna elements from amongst the set of alternate antenna elements (104).
8. A system (100) for determining one or more direction of arrivals (DOAs) for a receiver, the system (100) comprising:
a predefined number of antenna elements (102) adapted to receive a plurality of radio-frequency (RF) signals; and
at least one processor (106) in communication with the predefined number of antenna elements (102), the at least one processor (106) configured to:
compute a first weight matrix corresponding to the predefined number of antenna elements (102) and a plurality of first field of view (FOV) angles corresponding to the predefined number of antenna elements (102) based on a plurality of first predefined parameters;
estimate one or more coarse direction of arrivals (DOAs) corresponding to the plurality of received RF signals based on the first weight matrix;
compute a second weight matrix corresponding to a set of alternate antenna elements (104) among the predefined number of antenna elements (102) and a plurality of second FOV angles corresponding to the set of alternate antenna elements (104) among the predefined number of antenna elements (102) based on a plurality of second predefined parameters;
estimate a fine DOA corresponding to each of the one or more coarse DOAs based on the second weight matrix; and
determine the one or more DOAs for the receiver based on the estimated fine DOA.