DESC:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to wireless communication, and more specifically, relates to a method and system for automatic detection and adaptation of modulation at the receiver of a wireless communication system.

BACKGROUND
[0002] An example of such a system is recited in a patent US 10,476,628 B2 titled " adaptive coding and modulation (ACM) transceiver system” relates to controlling adaptive coding and modulation in a wireless communication environment. In this patent, ACM control is continuously modified by updating the SNR threshold at the transmitter for adaptive coding and modulation. For changing coding and modulation, it uses the SNR value received by the return path. Based on the reported SNR by return path, SNR threshold associated with each of the MODCODS is updated.
[0003] Another example is recited in the literature “Adaptive Coding and Modulation Experiment with NASA’s Space Communication and Navigation Testbed” In this paper results from the implementation of ACM over S-band using a direct-to-earth link are presented. To improve the system predictive and learning techniques to accommodate signal fades are given. This paper presents a neural network approach for ACM using the Levenberg-Marquardt learning method.
[0004] Another example is recited in the literature “Automatic Modulation Recognition Using Wavelet Transform and Neural Networks in Wireless Systems” In this paper, a training-based automatic modulation detection method which uses a neural network is presented. The features extracted from continuous wavelet transform are used for training the network and classification of modulations.
[0005] Yet another example is recited in a patent EP 2 828 997 B1 titled “method for generating a VCM or ACM signal having an improved frame” this patent is about improved frame structure as compared to DVB-S2 protocol frame structure. In this frame structure receiver synchronization is simpler and overhead is also less as compared to DVB-S2. VCM and ACM signals are generated with this frame structure.
[0006] Therefore, it is desired to overcome the drawbacks, shortcomings, and limitations associated with existing solutions, and develop a system and method for automatic detection and adaptation of modulation at the receiver of a wireless communication system

OBJECTS OF THE PRESENT DISCLOSURE
[0007] An object of the present disclosure relates, in general, to wireless communication, and more specifically, relates to a method and system for automatic detection and adaptation of modulation at the receiver of a wireless communication system.
[0008] Another object of the present disclosure is to provide a system and a method that achieve various data rates and more specifically for automatic identification of change in modulation, coding rate and adaptation to it at the receiver.
[0009] Another object of the present disclosure is to provide a system and a method that performs the insertion of different unique header sequences to the data frame for different modulations and different coding rates
[0010] Yet another object of the present disclosure is to provide a system that performs automatic adaptation to the modulation and coding rate in real-time.

SUMMARY
[0011] The present disclosure relates, in general, to wireless communication, and more specifically, relates to a method and system for automatic detection and adaptation of modulation at the receiver of a wireless communication system. In wireless communication over changing channel conditions, efficient use of channel bandwidth is done by using adaptive coding and modulation techniques. In this technique, the transmitter can use different modulations and coding rate combinations depending on the channel conditions. When channel conditions are favourable, high-order modulation and coding schemes with minimal overhead are used to maximize the data rate. But when the link is poor robust coding and lower-order modulation are used to maintain the connectivity. At the receiver identification of modulation and coding rate is required to change the demodulation and decoding accordingly.
[0012] The present disclosure relates to a system that involves automatic detection and adaptation of modulation in communication. It includes a processor operatively coupled to memory, which stores instructions executable by the processor to receive a set of data pertaining to I,Q samples from a transmitter. The received data is stored in a shift register array, requiring a separate array of length equal to the header length (H_Len) for I and Q samples. The processor analyzes the header of the received data using stored unique header sequences to determine communication parameters, such as modulation and coding rate.
[0013] Further, the processor estimates the header or start of the frame by cross-correlation between the stored set of data containing I,Q samples and stored unique headers periodically inserted in the frame at the transmitter. Parallel correlations corresponding to different headers, and thus different communication parameters, are computed simultaneously. The processor determines the communication parameters based on correlation values and hit points within a window of N frames for automatic detection and adaptation. Hit points corresponding to different headers are counted using separate counters within N consecutive frames, and the header with the largest count value determines the modulation and coding rate used by the transmitter. Finally, the processor switches the receiver to the determined demodulation and decoding rate by passing the communication parameters to equalizer, demodulation, and decoding modules.
[0014] Moreover, the system is capable of achieving various data rates, specifically enabling automatic identification of changes in modulation and coding rate at the receiver. Another object is to furnish a system and method that facilitates the insertion of diverse unique header sequences into data frames for different modulations and coding rates. Additionally, a further object is to offer a system enabling real-time automatic adaptation to modulation and coding rate.
[0015] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0017] FIG. 1 illustrates an exemplary block diagram of a system for detection and adaptation to modulation type and coding rate, in accordance with an embodiment of the present disclosure.
[0018] FIG. 2 illustrates an exemplary view of the processing element of the header detection block, in accordance with an embodiment of the present disclosure.
[0019] FIG. 3 illustrates an exemplary view of the processing element of decision-making block, in accordance with an embodiment of the present disclosure.
[0020] FIG. 4 illustrates an exemplary flow chart of a method for automatic detection and adaptation of modulation in communication, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0021] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0022] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0023] The present disclosure relates, in general, to wireless communication, and more specifically, relates to a method and system for automatic detection and adaptation of modulation at the receiver of a wireless communication system.
[0024] The present disclosure presents automatic detection and adaptation of change in modulation, coding rate referred to as communication parameters at the receiver when a communication transmitter executes changes in real-time. For the detection of the communication parameters the header in the received signal has to be analyzed because the information regarding the parameters is embedded in the header by the transmitter. This requires a correlation between the received data (I,Q) stored in an array and all possible headers. Parallel correlations are computed simultaneously corresponding to different headers which in turn correspond to different communication parameters.
[0025] The header whose rate of occurrence is highest leads to the decision on modulation and coding rate being used by the transmitter. The rate of occurrence of the different headers is estimated periodically. This is based on the concept of the hit point. At the end of a frame length of data, corresponding to a header, a hit point is declared if the correlation between the stored header sequence and the incoming data is more than a predefined threshold. These hit points are accumulated for N number of frames leading to counts for all possible headers. The largest count gives us the current modulation and coding rate used by the transmitter. Switching to the detected demodulation and decoding rate is executed at the receiver.
[0026] The present invention relates to a communication system having multiple modulations and coding schemes to achieve various data rates and more specifically for automatic identification of change in modulation, coding rate and adaptation to it at the receiver. An aspect of the present disclosure relates to the insertion of different unique header sequences to the data frame for different modulations and different coding rates. The identification of modulation and coding rate is done before demodulation and decoding of the data, at I,Q samples. According to the method received I,Q samples are analyzed to identify the modulation and coding rate by using the cross-correlation method. For identifying and adaptation of the modulation and coding rate in real-time, simultaneous multiple parallel cross-correlations are performed between received I,Q samples and stored headers. These multiple correlation values are monitored continuously to find which header pattern is matching for deciding the modulation, coding rate and the decision is passed to further modules for automatic adaptation to the modulation and coding rate in real-time. The present disclosure can be described in enabling detail in the following examples, which may represent more than one embodiment of the present disclosure.
[0027] The advantages achieved by the system of the present disclosure can be clear from the embodiments provided herein. The system and method achieve various data rates and more specifically automatic identification of change in modulation, coding rate and adaptation to it at the receiver. The system and a method perform the insertion of different unique header sequences to the data frame for different modulations and different coding rates at the transmitter and perform automatic adaptation to the modulation and coding rate in real-time at the receiver. The description of terms and features related to the present disclosure shall be clear from the embodiments that are illustrated and described; however, the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents of the embodiments are possible within the scope of the present disclosure. Additionally, the invention can include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.
[0028] FIG. 1 illustrates an exemplary block diagram of a system for detection and adaptation to modulation type and coding rate, in accordance with an embodiment of the present disclosure.
[0029] Referring to FIG. 1, the communication system 100 (also referred to as system 100, herein) configured for detection and adaptation to modulation type and coding rate is disclosed. The present describes the overall processing steps on the samples received from the communication channel. The different blocks in FIG. 1, are as follows storing of received In-phase (I) and Quadrature (Q) samples received by a receiver 102. The processor 110 is coupled to the receiver 102 and can include the parallel correlation modules 104, decision-making block 106 and switch modules 108. The parallel correlation modules 104 which correspond to different headers, the decision-making block 106 which uses correlations as the input and the switch module 108 configured to switch the receiver 102 to the detected demodulation and decoding rate.
[0030] The present disclosure system for automatic detection and adaptation of modulation in communication. The system 100 includes the processor 110 operatively coupled to a memory, the memory storing instructions executable by the processor 110 to receive a set of data pertaining to I,Q samples by a receiver 102 from a transmitter. The processor 104 stores the received set of data in a shift register array. The processor 104 stores the received set of data, requiring a separate array of length equal to header length (H_Len) for I and Q samples. The shift register array is an array of samples, in which a new incoming sample is latched and the oldest sample is exited
[0031] The processor 110 can analyse the header of the received set of data utilizing stored unique header sequences to determine the communication parameters of the received set of data. The communication parameters pertain to any or a combination of modulation and coding rates of the received set of data. The processor estimates the header or start of frame by performing cross-correlation between a stored set of data containing I,Q samples in the array and stored unique headers, the stored unique headers being one of the unique known patterns periodically inserted in the frame at the transmitter, with these unique known patterns differing for different modulations and coding rates.
[0032] The processor 110 computes parallel correlations simultaneously corresponding to different headers which in turn correspond to different communication parameters. The parallel correlations are performed by correlating with multiple values of stored headers corresponding to all possible modulations and coding rates. The processor 110 can determine a decision on the communication parameters being used by the transmitter based on correlation values, and count of hit points within a window of N frames to perform automatic detection and adaptation of the communication parameters. The decision on the communication parameters is based on the analysis of correlation values to detect the presence of a particular header, and hit points corresponding to different headers are counted using separate counters, wherein counting of hit points corresponding to all possible headers is performed in a given number of N consecutive frames, and the largest count value determines the header used by the transmitter, providing information on the modulation and coding rate.
[0033] The processor 110 is configured to switch the receiver 102 to the determined demodulation and decoding rate at the receiver. The processor switches to the detected demodulation and decoding rate by passing the communication parameters of the decision to equalizer, demodulation, and decoding modules.
[0034] The data samples received from the analog-to-digital converter (ADC) are the digital data of the in-phase and quadrature-phase components of the signal (I,Q samples). These I and Q samples are stored in two separate arrays of length H_len. Where H_len is the length of the header. At the transmitter, the unique known header is inserted at the starting of each frame. This header is used to identify the start of the frame and is used for synchronization at the receiver side. For different modulations and different coding rates, the different pattern of the unique header is inserted at the transmitter.
[0035] In an implementation, considering a total of ‘k’ different combination of modulation and coding rates exists in the transmitter then ‘k’ unique headers are used of length H_len. At the receiver, these headers are stored in arrays. Received I and Q samples are stored in a shift register array of length H_len in which a new incoming sample is latched and the oldest sample is exited. This shift register array is updated in real time whenever a new data sample comes. Whenever this shift register array is updated with a new data sample, parallel correlations with all k stored headers are performed. These correlation values of k parallel cross-correlation are used for further processing.
[0036] The cross-correlation method is used to find which header pattern is present in the received data. Once the header pattern is known corresponds to this header modulation and the coding rate is decided. Further, this decision is passed on to the next modules to adapt the modulation and coding rate. The demodulation and decoding blocks are adapted according to the parameter passed by the decision block 106.
[0037] FIG. 2 illustrates an exemplary view of the processing element of header block, in accordance with an embodiment of the present disclosure.
[0038] These k blocks correspond to each k stored header signal processing with received data. In block Ai, cross-correlation at block 204 is performed between received data stored in shift register array 202 and ith stored header 206. Where i=1,2,……k (k is the number of combinations of modulation and coding rate). Cross-correlation is performed whenever a new data sample is received and the correlation values are stored in an array called corr_value_array.
[0039] Array (corr_value_array) length is equal to frame length (Frm_len) 208. If the highest value of corr_value_array crosses the particular threshold 210 then it is declared a hit point 214 otherwise no action 212. Then next new correlation values are stored in corr_value_array to find next hit point is present or not. These hit points are counted by using a counter count_i. count_i corresponds to the header_i, likewise count_1, count_2…..count_k is the output of block A1, A2….Ak respectively. These count values are the deciding factor.
[0040] FIG. 3 illustrates an exemplary view of the processing element of decision-making block, in accordance with an embodiment of the present disclosure.
[0041] The decision-making block is the modulation and coding rate deciding block. Number of ‘hit point detected’ (count_i) information from all A blocks passes to decision making block. These hit points are counted in each A block for a specific time ‘T’. Where ‘T’ is the time period of ‘N’ frames. Time period ‘T’ is calculated by counting the number of frames till ‘N’ (frame_count) 302. Variable ‘frame_count’ is reset to ‘1’ when reaching to N to calculate time period ‘T’ periodically. When ‘frame_count’ becomes equal to ‘N’ 304 counters (count_1, count_2…..count_k) are compared to find the largest count 306. Largest count corresponding header gives us the information of current modulation and coding rate used by the transmitter 310. These counts (count_1, count_2…..count_k) are reset 312 after taking the decision and again used for counting the hit points. Decision is taken, in every time ‘T’ periodically. Decided modulation and coding rate information passed to the demodulation and decoding modules so that receiver may switch to correct modulation and coding rate in run time.
[0042] The present invention overcomes the drawbacks, shortcomings, and limitations associated with existing solutions, and provides a system and a method that achieve various data rates and more specifically for automatic identification of change in modulation, coding rate and adaptation at the receiver. The system and a method perform the insertion of different unique header sequences to the data frame for different modulations and different coding rates and performs automatic adaptation to the modulation and coding rate in real-time.
[0043] FIG. 4 illustrates an exemplary flow chart of a method for automatic detection and adaptation of modulation in communication, in accordance with an embodiment of the present disclosure.
[0044] The method 400 includes at block 402, receiving a set of data pertaining to I,Q samples from a transmitter at a receiver. At block 404, the processor can store the received set of data in a shift register array. The present disclosure relates to a method of automatic detection and adaptation of modulation. The method includes storing received I, Q samples in the shift register array. Real-time detection of any of the headers with the help of stored unique header sequences.
[0045] The automatic detection and adaptation of modulation and coding rate are performed on I,Q samples before demodulation or decoding of the data. The storing of received I,Q samples requires a separate array of length equal to header length (H_Len) for I and Q samples. The shift register array is an array of samples in which a new incoming sample is latched and the oldest sample is exited. The real-time estimation of the header or start of frame is performed by doing cross correlation between stored I,Q samples in the array and stored unique headers.
[0046] At block 406, the processor can analyze the header of the received set of data utilizing stored unique header sequences to determine communication parameters of the received set of data, the communication parameters pertain to any or a combination of modulation and coding rate of the received set of data. The stored unique headers are one of the unique known patterns periodically inserted in the frame at the transmitter. These known patterns are different for different modulations and coding rates.
[0047] At block 408, the processor can compute parallel correlations simultaneously corresponding to different headers, which in turn correspond to different communication parameters. Parallel correlations with stored unique headers for all possible modulations and coding rates simultaneously. The parallel correlations are performed by correlating with multiple values of stored headers corresponding to all possible modulations and coding rates.
[0048] At block 410, the processor can determine a decision on the communication parameters being used by the transmitter based on correlation values and count of hit points within a window of N frames to perform automatic detection and adaptation of the communication parameters. Decision on the modulation and coding rate based on the correlation values, using the count of hit points within a window of N frame and switching to the detected demodulation and decoding rate.
[0049] The decision on the modulation and coding rate is based on the correlation values, which are analyzed to detect the presence of a particular header. If the largest correlation value within a frame length window crosses the particular threshold then it is taken as the hit point of the particular header. These hit points are counted using separate counters corresponding to different headers.
[0050] Further, counting of the hit points corresponding to all possible headers is performed in a given number of N consecutive frames and the largest count value leads to the decision of header being used by the transmitter. This decision gives us the information of modulation and coding rate used by the transmitter.
[0051] At bock 412, the processor can switch to the determined demodulation and decoding rate at the receiver. The switching to the detected demodulation and decoding rate is achieved by passing the parameters of the decision to the equalizer, demodulation, and decoding modules.
[0052] It will be apparent to those skilled in the art that the system 100 of the disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT INVENTION
[0053] The present disclosure provides a system and a method that achieves various data rates and more specifically for automatic identification of change in modulation, coding rate and adaptation to it at the receiver.
[0054] The present disclosure provides a system and a method that performs the insertion of different unique header sequences to the data frame for different modulations and different coding rates.
[0055] The present disclosure is to provide a system that performs automatic adaptation to the modulation and coding rate in real-time.
,CLAIMS:1. A system (100) for automatic detection and adaptation of modulation in a communication, the system comprising:
a processor (110) operatively coupled to a memory, the memory storing instructions executable by the processor to:
receive, by a receiver (102), a set of data pertaining to in-phase (I) and quadrature (Q) samples from a transmitter;
store the received set of data in a shift register array;
analyse header of the received set of data utilizing stored unique header sequences to determine communication parameters of the received set of data, the communication parameters pertain to any or a combination of modulation and coding rate of the received set of data;
compute parallel correlations simultaneously corresponding to different headers which in turn correspond to different communication parameters;
determine a decision on the communication parameters being used by the transmitter based on correlation values, and count of hit points within a window of N frames to perform automatic detection and adaptation of the communication parameters; and
switch to the determined demodulation and decoding rate at the receiver.
2. The system as claimed in claim 1, wherein the automatic detection and adaptation of the communication parameters is performed on the received set of data before demodulation or decoding data.
3. The system as claimed in claim 1, wherein the processor (110) stores the received set of data, requiring a separate array of length equal to header length (H_Len) for I and Q samples.
4. The system as claimed in claim 1, wherein the shift register array is an array of samples, in which a new incoming sample is latched and the oldest sample is exited.
5. The system as claimed in claim 1, wherein the processor (110) estimates the header or start of frame by performing cross-correlation between the stored set of data containing I,Q samples in the array and stored unique headers, the stored unique headers being one of unique known patterns periodically inserted in the frame at the transmitter, with these unique known patterns differing for different modulations and coding rates.
6. The system as claimed in claim 1, wherein the parallel correlations are performed by correlating with multiple values of stored headers corresponding to all possible modulations and coding rates.
7. The system as claimed in claim 1, wherein the decision on the communication parameters is based on the analysis of the correlation values to detect the presence of a particular header, and hit points corresponding to different headers are counted using separate counters, wherein counting of hit points corresponding to all possible headers is performed in a given number of N consecutive frames, and the largest count value determines the header used by the transmitter, providing information on the modulation and coding rate.
8. The system as claimed in claim 1, wherein the processor (110) switches to the detected demodulation and decoding rate by passing the communication parameters of the decision to equalizer, demodulation, and decoding modules.
9. A method (400) for automatic detection and adaptation of modulation in a communication, the method, comprising:
receiving (402), at a receiver, a set of data pertaining to in-phase (I) and quadrature (Q) samples from a transmitter;
storing (404), at a processor, the received set of data in a shift register array;
analyzing (406), at the processor, header of the received set of data utilizing stored unique header sequences to determine communication parameters of the received set of data, the communication parameters pertain to any or a combination of modulation and coding rate of the received set of data;
computing (408), at the processor, parallel correlations simultaneously corresponding to different headers, which in turn correspond to different communication parameters;
determining (410) a decision on the communication parameters being used by the transmitter based on correlation values and count of hit points within a window of N frames to perform automatic detection and adaptation of the communication parameters; and
switching (412) to the determined demodulation and decoding rate at the receiver.