TECHNICAL FIELD

[001] The present disclosure generally relates to the field of telecommunication networking. More particularly, the present disclosure relates to a method and a system for generating a signal for wireless communication.

BACKGROUND

[002] Digital signals are widely used in modem radio wave communication systems. Digital information is embedded into a signal and the signal is transmitted. The main requirement in such radio wave communication systems is to reduce interference during transmission of signals. Conventionally, Orthogonal Frequency Division Multiplex (OFDM) is a dominant waveform used in wireless communications. The OFDM employs multiple complex sinusoids as carriers of the digital information. OFDM waveform eliminates Inter-Carrier Interference (ICI) in delay-spread multipath channels due to perfect orthogonality of OFDM subcarriers of the OFDM signal. When the wireless communication channel is affected by Doppler spread, the OFDM subcarriers lose the orthogonality due to multiple, path-dependent Doppler shifts in a narrowband or a wideband channel. In such cases, OFDM receivers need to employ sophisticated equalizers to eliminate the ICI, which increases cost and complexity in the radio wave communication systems.

[003] Also, the effect of the Doppler spread can be well approximated by a uniform shift of signal frequencies in the narrowband channel. However, in the wideband channels commonly encountered in, for example, Underwater Acoustic (UWA) or Ultra- Wideband (UWB) Radio Frequency (RF) communications, the effect of the Doppler spread is to time-compress or dilate a wideband signal, due to motion of source (or transmitter), receiver, or scatterer. The time-scaling on the wideband signal results in a non-uniform shift of signal frequencies across frequency band. The OFDM subcarriers and Orthogonal Time Frequency Space (OTFS) subcarriers are uniformly spaced in frequency domain and undergo frequency-dependent shifts in a wideband time-scale channel, which increases with frequency. The frequency-dependent shifts results in high ICI, which makes the performance of low complexity single-tap equalizers inefficient. [004] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY

[005] In an embodiment, the present disclosure discloses a method for generating a signal for wireless communication. The method comprises obtaining one or more pre-defined communication parameters of a wireless communication channel, comprising at least a lower cutoff frequency and an upper cut-off frequency. Further, the method comprises determining a bandwidth of each of a plurality of subcarriers of a signal for the wireless communication. The bandwidth is determined based on the lower cut-off frequency, the upper cut-off frequency, a symbol bandwidth of one or more symbols of each of the plurality of subcarriers, and a number of the plurality of subcarriers. Furthermore, the method comprises determining one or more parameters of each of the plurality of subcarriers, based on the corresponding bandwidth and a predetermined maximum time-scaling factor associated with the wireless communication channel. Thereafter, the method comprises generating the signal comprising the plurality of subcarriers, for the wireless communication, based on the one or more parameters of each of the plurality of subcarriers.

[005] In an embodiment, the present disclosure discloses a system for generating a signal for wireless communication. The system comprises one or more processors and a memory. The one or more processors are configured to obtain one or more pre -defined communication parameters of a wireless communication channel, comprising at least a lower cut-off frequency and an upper cut-off frequency. Further, the one or more processors are configured to determine a bandwidth of each of a plurality of subcarriers of a signal for the wireless communication. The bandwidth is determined based on the lower cut-off frequency, the upper cut-off frequency, a symbol bandwidth of one or more symbols of each of the plurality of subcarriers, and a number of the plurality of subcarriers. Furthermore, the one or more processors are configured to determine one or more parameters of each of the plurality of subcarriers, based on the corresponding bandwidth and a predetermined maximum time-scaling factor associated with the wireless communication channel. Thereafter, the one or more processors are configured to generate the signal comprising the plurality of subcarriers, for the wireless communication, based on the one or more parameters of each of the plurality of subcarriers. [006] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[007] The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

[008] Figure 1 illustrates an exemplary environment for generating a signal for wireless communication, in accordance with some embodiments of the present disclosure;

[009] Figure 2 illustrates a detailed diagram of a system for generating the signal for the wireless communication, in accordance with some embodiments of the present disclosure;

[0010] Figure 3 shows an exemplary flow chart illustrating method steps for generating the signal for the wireless communication, in accordance with some embodiments of the present disclosure;

[0011] Figures 4, 5A, and 5B illustrate exemplary graphs showing a comparison of performance of the signal of the present disclosure with conventional signals, in accordance with some embodiments of the present disclosure; and

[0012] Figures 6 shows a block diagram of a general-purpose computing system for generating the signal for the wireless communication, in accordance with embodiments of the present disclosure.

[0013] It should be appreciated by those skilled in the art that any block diagram herein represents conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION

[0014] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0015] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0016] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises ... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.

[0017] Transmission from a multi-carrier digital communication system requires continuous time subcarrier waveforms that embed the digital symbols to be transmitted in a wireless communication channel. Also, it is required to limit interference between the subcarrier waveforms at a receiver end, so as to reduce one or more complexities at the receiver end. Conventionally, Orthogonal Frequency Division Multiplex (OFDM) and Orthogonal Time Frequency Space (OTFS) waveforms are used which eliminates Inter-Carrier Interference (ICI) in delay-spread multipath channels. However, the orthogonality is lost when the wireless communication channel is affected by Doppler spread. [0018] The present disclosure provides a method and a system for generating a signal for wireless communication. The present disclosure provides a Variable Bandwidth Multicarrier (VBMC) waveform or a signal that involves a plurality of subcarriers that are constructed from chirp pulses. The plurality of subcarriers occupies progressively increasing, frequency-dependent bandwidth from lower to upper frequency edge of a communication band. The variable bandwidth eliminates multiple, time-scaling distortions caused by the Doppler spread. The plurality of subcarriers maintain a near mutual orthogonality even after passing through a delay and scale spread channel. The orthogonality results in a low ICI among the plurality of subcarriers of the VBMC, and thereby facilitates a low complexity subcarrier-by-subcarrier decoding at a receiver. The VBMC increases Signal-to-Interference Ratio (SIR) and lowers channel to channel variation across symbols at the receiver, thus improving Bit Error Rate (BER) performance. Thus, the VMBC can be employed in wideband communication such as, Underwater Acoustic (UWA), Ultra-Wideband (UWB) Radio Frequency (RF) communications, and the like.

[0019] Figure 1 illustrates an exemplary environment 100 for generating a signal for wireless communication, in accordance with some embodiments of the present disclosure. The environment 100 comprises a transmitter 101, a receiver 102, a wireless communication channel 103, a system 104, and one or more sources 105. The transmitter 101 and the receiver 102 communicate wirelessly over a communication network. The communication network may be a radio wave communication network such as, Underwater Acoustic (UWA), Ultra-Wideband (UWB) Radio Frequency (RF) communications, and the like. Signals comprising data are transmitted from the transmitter 101 to the receiver 102 over the wireless communication channel 103. The system 104 is used for generating the signal for the wireless communication. Firstly, the system 104 obtains one or more pre-defined communication parameters of the wireless communication channel 103, comprising a lower cut-off frequency and an upper cut-off frequency. The system 104 may obtain the one or more pre-defined communication parameters from one or more sources 105. Subsequently, the system 104 may determine a bandwidth of each of a plurality of subcarriers 106i, IO62, , 106N of a signal 107 illustrated in Figure 1. The data to be transmitted over the wireless communication channel 103 is split into multiple sub-streams and transmitted over the plurality of subcarriers IO61, IO62, > , 106N. The plurality of subcarriers 1061, IO62, > , 106N are referred as the plurality of subcarriers 106 hereafter in the present description. The bandwidth of the plurality of subcarriers 106 is determined based on a symbol bandwidth of one or more symbols of each of the plurality of subcarriers 106, and the number of the plurality of subcarriers 106. Further, the system 104 may determine one or more parameters of each of the plurality of subcarriers 106, based on the corresponding bandwidth and a pre-determined maximum time-scaling factor associated with the wireless communication channel 103. Then, the system 104 generates the signal 107 comprising the plurality of subcarriers 106, for the wireless communication, based on the one or more parameters of each of the plurality of subcarriers 106.

[0020] Figure 2 illustrates a detailed diagram 200 of the system 104 for generating the signal 107 for the wireless communication, in accordance with some embodiments of the present disclosure. The system 104 may include Input/ Output (I/O) interface 201, a memory 202, and Central Processing Units 203 (also referred as “CPUs” or “one or more processors 203”). In some embodiments, the memory 202 may be communicatively coupled to the one or more processors 203. The memory 202 stores instructions executable by the one or more processors 203. The one or more processors 203 may comprise at least one data processor for executing program components for executing user or system -generated requests. The memory 202 may be communicatively coupled to the one or more processors 203. The memory 202 stores instructions, executable by the one or more processors 203, which, on execution, may cause the one or more processors 203 to generate the signal 107 for the wireless communication. The I/O interface 201 is coupled with the one or more processors 203 through which an input signal or/and an output signal is communicated. For example, the one or more pre-defined communication parameters may be received from the one or more sources 105 via the I/O interface 201. In an embodiment, the system 104 may be implemented in a variety of computing systems, such as a laptop computer, a desktop computer, a Personal Computer (PC), a notebook, a smartphone, a tablet, a server, a network server, a cloud-based server, and the like.

[0021] In an embodiment, the memory 202 may include one or more modules 205 and data 204. The one or more modules 205 may be configured to perform the steps of the present disclosure using the data 204, to generate the signal 107 for the wireless communication. In an embodiment, each of the one or more modules 205 may be a hardware unit which may be outside the memory 202 and coupled with the system 104. As used herein, the term modules 205 refers to an Application Specific Integrated Circuit (ASIC), an electronic circuit, a Field-Programmable Gate Arrays (FPGA), Programmable System-on-Chip (PSoC), a combinational logic circuit, and/or other suitable components that provide described functionality. The one or more modules 205 when configured with the described functionality defined in the present disclosure will result in a novel hardware. [0022] In one implementation, the modules 205 may include, for example, an input module 211, a first determination module 212, a second determination module 213, a signal generation module 214, and other modules 215. It will be appreciated that such aforementioned modules 205 may be represented as a single module or a combination of different modules. In one implementation, the data 204 may include, for example, an input data 206, a first determination data 207, a second determination data 208, a signal generation data 209, and other data 210.

[0023] In an embodiment, the input module 211 is configured to obtain one or more pre-defined communication parameters of the wireless communication channel 103. The one or more predefined communication parameters may comprise at least a lower cut-off frequency and an upper cut-off frequency of the wireless communication channel 103. In an embodiment, the lower cutoff frequency and the upper cut-off frequency specifies a range of frequencies over which a gain or output power does not deviate more than 70.7% of the maximum gain. In an example, the lower cut-off frequency may be 3.1 GHz and the upper cut-off frequency may be 10.6 GHz for the UWB RF communication. In another example, the lower cut-off frequency may be 10 kHz and the upper cut-off frequency may be 20 kHz for the UWA communication. In yet another example, the lower cut-off frequency may be 10 kHz and the upper cut-off frequency may be 20 kHz for the UWA communication for long range communication (>1 km). The lower cut-off frequency and the upper cutoff frequency are represented as ‘ft’ and TH’, respectively in the present description.

[0024] The one or more pre-defined communication parameters further comprises at least one of, a symbol duration, and a pulse shaping factor. The symbol duration refers to a number of symbols transmitted per second. The symbol duration is represented as ‘T’ in the present description. Pulse shaping is a process of changing a waveform of transmitted pulses to match a bandwidth of the transmitted pulse with a bandwidth of the wireless communication channel 103. The effective bandwidth of the transmission is limited based on the pulse shaping factor. The pulse shaping factor may be, for example, two. The pulse shaping factor is represented as ‘P’ in the present description. In an embodiment, the one or more pre-defined communication parameters may be received from the one or more sources 105. For example, the one or more sources 105 may be a user designing the wireless communication channel 103. In another example, the one or more sources 105 may comprise a database associated with the input module 211. The input module 211 may determine the one or more pre-defined communication parameters and store in the database. In another example, the input module 211 may obtain at least one pre-defined communication parameter from the user and determine other pre-defined communication parameters. The one or more pre-defined communication parameters may be stored as the input data 206 in the memory 202.

[0025] In an embodiment, the first determination module 212 may be configured to obtain the input data 206 from the input module 211. Further, the first determination module 212 may be configured to determine a bandwidth of each of the plurality of subcarriers 106 of the signal 107 for the wireless communication, based on the lower cut-off frequency, the upper cut-off frequency, the symbol bandwidth of one or more symbols of each of the plurality of subcarriers 106, and the number of the plurality of subcarriers 106. The communication band from ‘ft’ to ‘fii’ is divided into ‘N’ frequency cells of varying widths. A subcarrier from the plurality of subcarriers 106 is associated with each cell. The plurality of subcarriers 106 are chirp pulses. In an example, the plurality of subcarriers 106 is Linear Frequency Modulated (LFM) chirp pulses that sweep a bandwidth depending on the respective frequency cell. A width of the frequency cell which is also referred as symbol bandwidth is represented as ‘AT. The symbol bandwidth is determined based on the symbol duration and the pulse shaping factor, and is in the form of equation (1) provided below as:

The number of the plurality of subcarriers 106 is determined based on the lower cut-off frequency and the upper cut-off frequency, and is in the form of equation (2) provided below as: where when a value of ‘N’ on a right side of the equation (2) is a non-integer value, the value of ‘N’ is considered as a largest integer smaller than the non-integer value. For instance, when the value of ‘N’ on the right side is determined as 6.5, the value of ‘N’ is considered as 6. The first determination module 212 determines the bandwidth of each of the plurality of subcarriers 106 based on the lower cut-off frequency, the upper cut-off frequency, the symbol bandwidth of one or more symbols of each of the plurality of subcarriers 106, and the number of the plurality of subcarriers 106. The bandwidth of each of the plurality of subcarriers 106 is in the form of equation (3) provided below as: where ‘n’ varies from 0 to N - 1 and ‘fo’ is ‘ft’ . Hence, the present disclosure considers a frequency dependent bandwidth for the plurality of subcarriers 106 to eliminate a non-uniform shift of signal frequencies. The bandwidth of each of the plurality of subcarriers 106 may be stored as the first determination data 207 in the memory 202. [0026] In an embodiment, the second determination module 213 is configured to obtain the first determination data 207 from the first determination module 212. Further, the second determination module 213 is configured to determine one or more parameters of each of the plurality of subcarriers 106. The second determination module 213 determines the one or more parameter based on the corresponding bandwidth and a pre-determined maximum time-scaling factor associated with the wireless communication channel 103. The one or more parameters of each of the plurality of subcarriers 106 may comprise at least one of, a subcarrier pulse duration, a subcarrier chirp rate, and a subcarrier chirp centre frequency. The subcarrier pulse duration is a time interval between a first transition and a last transition when an amplitude of a pulse reaches a specified level of a final amplitude and drops again to the same specified level. The subcarrier pulse duration is determined based on the bandwidth of each of the plurality of subcarriers 106, a pre-determined time-scaling factor associated with the wireless communication channel 103, and the symbol duration. The subcarrier pulse duration is in the form of equation (4) provided below as: where ‘a _ma x’ is the pre-determined maximum time-scaling factor.

[0027] The subcarrier chirp rate is a rate at which a frequency of the subcarrier changes with time. The subcarrier chirp rate is determined based on the bandwidth of each of the plurality of subcarriers 106, the pre-determined maximum time-scaling factor associated with the wireless communication channel (103), and the subcarrier pulse duration. The subcarrier chirp rate is in the form of equation (5) provided below as:

The subcarrier chirp centre frequency is determined based on the bandwidth of each of the plurality of subcarriers 106 and the pre-determined maximum time-scaling factor associated with the wireless communication channel 103. The subcarrier chirp centre frequency is in the form of equation (6) provided below as:

[0028] The pre-determined maximum time-scaling factor is determined by a user for the wireless communication channel 103. The pre-determined maximum time-scaling factor is determined as follows:

Consider a signal s(t) transmitted over the wireless communication channel 103. The wireless communication channel 103 timescales and delays the signal by a and T , respectively, and modifies the signal amplitude by h. The signal at the channel output is given by equation (7) below as:

The wireless communication channel in (7) is due to a single moving scatterer whose velocities relative to the transmitter 101 and receiver 102 determine the value of a, distances from the transmitter 101 and receiver 102 determine T, and a path loss from the transmitter 101 to the receiver 102 via a scatterer determines h. Amplitude scaling by \fa in (7) preserves energy of the signal s(t) when the path loss is zero (i.e., h = 1). Also, the time-scaling and delay operations are not commutative: the wireless communication channel 103 in (7) delivers which is a delayed version of the time-scaled signal s(at), and not s(at — T), the time-scaled version of the delayed signal s(t — T). A spectrum of the received signal is given by equation (8) below as: j = V— 1 • Therefore, a spectral component of the transmitted signal at a frequency, f = f ₀ , appears at f = af ₀ at the receiver 102 with a phase change of (relative to the phase when ct = 1) since

Thus, a spectral component of the signal at frequency / shifts in frequency by an amount 8f = (a — 1)/ along with a phase modification of _e -) ² ^ ^a -P>f ^T _{as a} result of the timescale. When there are P scatterers, the received signal is a superposition of signals due to each scatterer, which is represented in equation (9) provided below as: where a triple (h _p , i _p , a _p ^ contains the amplitude, delay and timescale parameters associated with the pth scatterring path. a _max > 1 and r _max > 0 are denoted to be the scale and delay spread, respectively, of the wideband channel, so that and to obtain a discrete-time signal. The wireless communication channel 103 in (9), due to the multiple scatterers with possibly different triples is known as the delay-scale spread channel. Inverse time-scaling of the received signal, i.e., r _s Q) removes the effect of time scaling by a single scatterer. Time-scaling of a discrete time signal results in a sample rate change by a rational approximation of ’a ." The present disclosure considers such time-scaling factor to take into account the presence of the multiple scatterers moving at different velocities or located at different angles relative to the receiver 102 for computing the maximum pre-determined time scaling factor amax. The maximum pre-determined time scaling factor a _m ax may be used by both the transmitter 101 and the receiver 102 for constructing the signal. The one or more parameters of each of the plurality of subcarriers 106 may be stored as the second determination data 208 in the memory 202.

[0029] In an embodiment, the signal generation module 214 is configured to receive the second determination data 208 from the second determination module 213. Further, the signal generation module 214 is configured to generate the signal 107 for the wireless communication. The signal 107 comprise the plurality of subcarriers 106. The signal generation module 214 generates the signal 107 based on the one or more parameters of each of the plurality of subcarriers 106. The signal 107 is in the form of equation 10 provided below: where ‘T _n ’ is the subcarrier pulse duration of each of the plurality of subcarriers 106, ‘f _c , _n ’ is a subcarrier chirp centre frequency of each of the plurality of subcarriers 106, ‘k _n ’ is a subcarrier chirp rate of each of the plurality of subcarriers 106, and ‘t’ denotes time which ranges between -Tn/2 < t < Tn/2.

Hence, the signal 107 provided in equation (10) may be generated for a particular wireless communication channel 103 by considering the maximum pre-determined scaling factor a _m ax to eliminate inter subcarrier interference arising from non-uniform shift of signal frequencies In an embodiment, the signal 107 provided in equation (10) may be windowed by a pulse shaping function of matched duration (duration of the signal 107). The pulse shaping function is applied to reduce out of band spectral level. An exemplary pulse shaping function is a Dolph Chebyshev window designed for a side lobe level of, for example, -20 dB. A person skilled in the art will appreciate that pulse shaping functions other than the above-mentioned pulse shaping function may be used for windowing the signal 107.

[0030] The other data 210 may store data, including temporary data and temporary files, generated by the one or more modules 205 for performing the various functions of the system 104. The other data 210 may be stored in the memory 202. The one or more modules 205 may also include the other modules 215 to perform various miscellaneous functionalities of the system 104. It will be appreciated that the one or more modules 205 may be represented as a single module or a combination of different modules.

[0031] Figure 3 shows an exemplary flow chart illustrating method steps for generating the signal 107 for the wireless communication, in accordance with some embodiments of the present disclosure. As illustrated in Figure 3, the method 300 may comprise one or more steps. The method 300 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform particular functions or implement particular abstract data types.

[0032] The order in which the method 300 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof.

[0033] At step 301, the system 104 obtains the one or more pre -defined communication parameters of the wireless communication channel 103. The one or more pre-defined communication parameters may comprise at least a lower cut-off frequency and an upper cut-off frequency of the wireless communication channel 103. The lower cut-off frequency and the upper cut-off frequency specifies a range of frequencies over which a gain or output power does not deviate more than 70.7% of the maximum gain. The one or more pre-defined communication parameters further comprises at least one of, the symbol duration, and the pulse shaping factor. The symbol duration refers to a number of symbols transmitted per second. The effective bandwidth of the transmission is limited based on the pulse shaping factor.

[0034] At step 302, the system 104 determines the bandwidth of each of the plurality of subcarriers 106 of the signal 107 for the wireless communication, based on the lower cut-off frequency, the upper cut-off frequency, the symbol bandwidth of the one or more symbols of each of the plurality of subcarriers 106, and the number of the plurality of subcarriers 106. The symbol bandwidth is determined based on the symbol duration and the pulse shaping factor. The number of the plurality of subcarriers 106 is determined based on the lower cut-off frequency and the upper cut-off frequency.

[0035] At step 303, the system 104 determines the one or more parameters of each of the plurality of subcarriers 106, based on the corresponding bandwidth and the pre-determined maximum time-scaling factor associated with the wireless communication channel 103.The one or more parameters of each of the plurality of subcarriers 106 may comprise at least one of, a subcarrier pulse duration, a subcarrier chirp rate, and a subcarrier chirp centre frequency. The subcarrier pulse duration is determined based on the bandwidth of each of the plurality of subcarriers 106, the pre-determined time-scaling factor associated with the wireless communication channel 103, and the symbol duration. The subcarrier chirp rate is a rate at which a frequency of the subcarrier changes with time. The subcarrier chirp rate is determined based on the bandwidth of each of the plurality of subcarriers 106, the pre-determined maximum time-scaling factor associated with the wireless communication channel 103, and the subcarrier pulse duration. The subcarrier chirp centre frequency is determined based on the bandwidth of each of the plurality of subcarriers 106 and the pre-determined maximum time-scaling factor associated with the wireless communication channel 103.

[0036] At step 304, the system 104 generates the signal 107 for the wireless communication. The signal 107 comprises the plurality of subcarriers 106. The system 104 generates the signal 107 based on the one or more parameters of each of the plurality of subcarriers 106. The signal 107 is generated based on the subcarrier pulse duration of each of the plurality of subcarriers 106, the subcarrier chirp centre frequency of each of the plurality of subcarriers 106, and the subcarrier chirp rate of each of the plurality of subcarriers 106.

[0037] Figure 4 illustrates exemplary graphs showing a comparison of performance of OFDM, OTFS, and VMBC. Consider a delay scale channel with 20 paths, a maximum delay r _m ax of 10 ms, and the pre-determined time scaling factor amax of 1.001 exists. A magnitude of the signal 107 (in dB) are color-coded with the highest magnitude represented by bright yellow and the lowest by dark blue color for OFDM, OTFS, VMBC in 401, 402, and 403, respectively. The ICI obtained for the OFDM, OTFS, and VMBC are 6.2 dB, -5.4 dB, -5.9 dB, respectively. The Signal-to-Interference Ratio (SIR) obtained for the OFDM, OTFS, and VMBC -12.6 dB, -12.6 dB, and 1 dB, respectively. The least ICI and highest SIR is obtained for the VMBC. Figure 5A and Figure 5B shows exemplary graphs illustrating Bit Error Rate (BER) performance of OFDM, OFTS, and VMBC. Figure 5A illustrates an exemplary graph illustrating the BER performance of OFDM, OFTS, and VMBC considering, for example, number of scatterers P as 20, maximum delay spread ‘r _m ax’ as 10ms, maximum pre-determined time scaling factor ‘a _m ax’ as 1.001, and ‘T^xS^ax" as 0.2 Figure 5B illustrates an exemplary graph illustrating BER performance of OFDM, OFTS, and VMBC, considering, for example for number of scatterers P as 20, maximum delay spread ‘rmax’ as 20ms, maximum pre-determined time scaling factor ‘a _m ax’ as 1.002, and ‘T^xS^ax" as 0.8. It can be inferred from the Figure 5A and 5B that the least BER is obtained for the VMBC based communication system.

[0038] Figure 6 illustrates a block diagram of an exemplary computer system 600 for implementing embodiments consistent with the present disclosure. In an embodiment, the computer system 600 may be the system 104. Thus, the computer system 600 may be used to generate the signal for the wireless communication. In an embodiment, the computer system 600 may obtain the one or more pre-defined communication parameters over a communication network 609. The computer system 600 may comprise a Central Processing Unit 602 (also referred as “CPU” or “processor”). The processor 602 may comprise at least one data processor. The processor 602 may include specialized processing units such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc.

[0039] The processor 602 may be disposed in communication with one or more input/output (I/O) devices (not shown) via I/O interface 601. The I/O interface 601 may employ communication protocols/methods such as, without limitation, audio, analog, digital, monoaural, RCA, stereo, IEEE (Institute of Electrical and Electronics Engineers) -1394, serial bus, universal serial bus (USB), infrared, PS/2, BNC, coaxial, component, composite, digital visual interface (DVI), high- definition multimedia interface (HDMI), Radio Frequency (RF) antennas, S-Video, VGA, IEEE 8O2.n /b/g/n/x, Bluetooth, cellular (e.g., code-division multiple access (CDMA), high-speed packet access (HSPA+), global system for mobile communications (GSM), long-term evolution (LTE), WiMax, or the like), etc.

[0040] Using the I/O interface 601, the computer system 600 may communicate with one or more I/O devices. For example, the input device 610 may be an antenna, keyboard, mouse, joystick, (infrared) remote control, camera, card reader, fax machine, dongle, biometric reader, microphone, touch screen, touchpad, trackball, stylus, scanner, storage device, transceiver, video device/source, etc. The output device 611 may be a printer, fax machine, video display (e.g., cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), plasma, Plasma display panel (PDP), Organic light-emitting diode display (OLED) or the like), audio speaker, etc.

[0041] The processor 602 may be disposed in communication with the communication network 609 via a network interface 603. The network interface 603 may communicate with the communication network 609. The network interface 603 may employ connection protocols including, without limitation, direct connect, Ethernet (e.g., twisted pair 10/100/1000 Base T), transmission control protocol/intemet protocol (TCP/IP), token ring, IEEE 802.11a/b/g/n/x, etc. The communication network 609 may include, without limitation, a direct interconnection, local area network (LAN), wide area network (WAN), wireless network (e.g., using Wireless Application Protocol), the Internet, etc. The network interface 603 may employ connection protocols include, but not limited to, direct connect, Ethernet (e.g., twisted pair 10/100/1000 Base T), transmission control protocol/intemet protocol (TCP/IP), token ring, IEEE 802.11a/b/g/n/x, etc.

[0042] The communication network 609 includes, but is not limited to, a direct interconnection, an e-commerce network, a peer to peer (P2P) network, local area network (LAN), wide area network (WAN), wireless network (e.g., using Wireless Application Protocol), the Internet, WiFi, and such. The first network and the second network may either be a dedicated network or a shared network, which represents an association of the different types of networks that use a variety of protocols, for example, Hypertext Transfer Protocol (HTTP), Transmission Control Protocol/intemet Protocol (TCP/IP), Wireless Application Protocol (WAP), etc., to communicate with each other. Further, the first network and the second network may include a variety of network devices, including routers, bridges, servers, computing devices, storage devices, etc.

[0043] In some embodiments, the processor 602 may be disposed in communication with a memory 605 (e.g., RAM, ROM, etc. not shown in Figure 6) via a storage interface 604. The storage interface 604 may connect to memory 605 including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as serial advanced technology attachment (SATA), Integrated Drive Electronics (IDE), IEEE- 1394, Universal Serial Bus (USB), fiber channel, Small Computer Systems Interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, Redundant Array of Independent Discs (RAID), solid-state memory devices, solid-state drives, etc.

[0044] The memory 605 may store a collection of program or database components, including, without limitation, user interface 606, an operating system 607, web browser 608 etc. In some embodiments, computer system 600 may store user/application data, such as, the data, variables, records, etc., as described in this disclosure. Such databases may be implemented as fault- tolerant, relational, scalable, secure databases such as Oracle ® or Sybase®.

[0045] The operating system 607 may facilitate resource management and operation of the computer system 600. Examples of operating systems include, without limitation, APPLE MACINTOSH'* OS X, UNIX ^R , UNIX-like system distributions (E.G, BERKELEY SOFTWARE DISTRIBUTION™ (BSD), FREEBSD™, NETBSD™, OPENBSD™, etc ), LINUX DISTRIBUTIONS™ (E.G, RED HAT™, UBUNTU™, KUBUNTU™, etc ), IBM™ OS/2, MICROSOFT™ WINDOWS™ (XP™, VISTA™/7/8, 10 etc ), APPLE ^R IOS™, GOOGLE ^R ANDROID™, BLACKBERRY ^R OS, or the like.

[0046] In some embodiments, the computer system 600 may implement the web browser 608 stored program component. The web browser 608 may be a hypertext viewing application, for example MICROSOFT'* INTERNET EXPLORER™, GOOGLE ^R CHROME™ ⁰ , MOZILLA ^R FIREFOX™, APPLE ^R SAFARI™, etc. Secure web browsing may be provided using Secure Hypertext Transport Protocol (HTTPS), Secure Sockets Layer (SSL), Transport Layer Security (TLS), etc. Web browsers 608 may utilize facilities such as AJAX™, DHTML™, ADOBE ^R FLASH™, JAVASCRIPT™, JAVA™, Application Programming Interfaces (APIs), etc. In some embodiments, the computer system 600 may implement a mail server (not shown in Figure) stored program component. The mail server may be an Internet mail server such as Microsoft Exchange, or the like. The mail server may utilize facilities such as ASP™, ACTIVEX™, ANSI™ C++/C#, MICROSOFT ¹ *, NET™, CGI SCRIPTS™, JAVA™, JAVASCRIPT™, PERL™, PHP™, PYTHON™, WEBOBJECTS™, etc. The mail server may utilize communication protocols such as Internet Message Access Protocol (IMAP), Messaging Application Programming Interface (MAPI), MICROSOFT ¹ * exchange, Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), or the like. In some embodiments, the computer system 600 may implement a mail client stored program component. The mail client (not shown in Figure) may be a mail viewing application, such as APPLE ¹ * MAIL™, MICROSOFT ¹ * ENTOURAGE™, MICROSOFT ¹ * OUTLOOK™, MOZILLA ¹ * THUNDERBIRD™, etc.

[0047] Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present disclosure. A computer-readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term “computer- readable medium” should be understood to include tangible items and exclude carrier waves and transient signals, i.e., be non-transitory. Examples include Random Access Memory (RAM), Read-Only Memory (ROM), volatile memory, non-volatile memory, hard drives, Compact Disc Read-Only Memory (CD ROMs), Digital Video Disc (DVDs), flash drives, disks, and any other known physical storage media. [0048] The present disclosure provides a method and a system for generating a signal for wireless communication. The present disclosure provides a Variable Bandwidth Multicarrier (VBMC) waveform or a signal that involves a plurality of subcarriers that are constructed from chirp pulses. The plurality of subcarriers occupies progressively increasing, frequency-dependent bandwidth from lower to upper frequency edge of a communication band. The variable bandwidth eliminates multiple, time-scaling distortions caused by the Doppler spread. The plurality of subcarriers maintain mutual orthogonality even after passing through a delay and scale spread channel. The orthogonality results in a low ICI among the plurality of subcarriers of the VBMC, and thereby facilitates a low complexity subcarrier-by-subcarrier decoding at a receiver. The VBMC increases Signal-to-Interference Ratio (SIR) and lowers channel to channel variation across symbols at the receiver, thus improving Bit Error Rate (BER) performance . Thus, the VMBC can be employed in wideband communication such as Underwater Acoustic (UWA), Ultra-Wideband (UWB) Radio Frequency (RF) communications, and the like.

[0049] The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the embodiments", "one or more embodiments", "some embodiments", and "one embodiment" mean "one or more (but not all) embodiments of the invention(s)" unless expressly specified otherwise.

[0050] The terms "including", "comprising", “having” and variations thereof mean "including but not limited to", unless expressly specified otherwise.

[0051] The enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms "a", "an" and "the" mean "one or more", unless expressly specified otherwise.

[0052] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

[0053] When a single device or article is described herein, it will be readily apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device/article may be used in place of the more than one device or article, or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself.

[0054] The illustrated operations of Figure 3 shows certain events occurring in a certain order. In alternative embodiments, certain operations may be performed in a different order, modified, or removed. Moreover, steps may be added to the above-described logic and still conform to the described embodiments. Further, operations described herein may occur sequentially or certain operations may be processed in parallel. Yet further, operations may be performed by a single processing unit or by distributed processing units.

[0055] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[0056] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

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