Multi-stage burst detection for a communication system

Abstract

The present disclosure describes systems and methods that enable a user terminal to eliminate or reduce the number of false bursts (or bursts without data) that it transmits. These systems and methods use two burst detectors - a first burst detector that analyzes the physical structure of a signal and a second burst detector that analyzes the information structure of a signal. The output from the first burst detector can be used to control the operation of a signal decoder that decodes a received signal. The second burst detector analyzes the output from the signal decoder to determine a second burst indicator. In other words, the first burst detector can be implemented prior to decoding the received signal to provide a first estimate as to the presence or absence of a burst. The first estimate can then be used to limit the amount of processing performed by the signal decoder.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 005,997, filed April 6, 2020, entitled “SATELLITE COMMUNICATION SYSTEMBURST DETECTOR,” the entire contents of which are expressly incorporated herein by reference for all purposes. Background Technology Technical Field

[0003] This disclosure relates in general to detecting whether or not a burst originates from a user terminal in a communication system.

[0004] Related technologies

[0005] Network communication involves sending data back and forth between nodes such as content servers and user terminals. To send user data over a network, a scheduler can be used to allocate network resources to devices, creating a scheduling schedule for device transmissions. Based on this schedule, each device can then use the allocated resources to transmit data. Based on the scheduling schedule, a user terminal can transmit data to a receiver, which is part of the communication system, to forward the data to its final destination. Summary of the Invention

[0006] This disclosure relates to a receiver for a communication system. The receiver includes a first burst detector configured to receive a digitized signal transmitted through a channel and generate a first burst indicator by analyzing the physical structure of the received digitized signal to determine whether a burst exists in the received digitized signal. The receiver also includes a second burst detector configured to generate a second burst indicator by analyzing the information structure of a decoded signal corresponding to the received digitized signal to determine whether a burst exists in the received digitized signal.

[0007] In some embodiments, the receiver further includes an iterative decoder configured to decode the received digitized signal by iteratively processing the received digital signal to generate a decoded signal, the number of iterations being influenced by a first burst indicator generated by a first burst detector. In another embodiment, the iterative decoder and the first burst detector operate at least partially in parallel. In yet another embodiment, the number of iterations is limited to a minimum number of iterations if the first burst indicator indicates that there is no burst in the received digital signal, and the number of iterations is limited to a maximum number of iterations if the burst indicator indicates that there is a burst in the received digital signal, wherein the maximum number of iterations is greater than the minimum number of iterations. In yet another embodiment, the response to the first burst indicator indicating a burst in the received digital signal is indeterminate, and the number of iterations is between the minimum and maximum number of iterations. In yet another embodiment, the first burst detector estimates the probability that a burst exists in the received digital signal, and the number of iterations is influenced by the estimated probability.

[0008] In some embodiments, the first burst detector uses data-assisted analysis based on known pilot symbols to analyze the physical structure of the received digital signal. In another embodiment, the known pilot symbols include the amble of the received digital signal. In yet another embodiment, the first burst detector uses the Neyman-Pearson generalized likelihood ratio test (NP-GLRT) to analyze the physical structure of the received digital signal. In yet another embodiment, the first burst detector uses a constant false alarm rate (CFAR) detector to analyze the physical structure of the received digital signal. In yet another embodiment, the constant false alarm rate detector includes a constant false alarm rate ratio summation (CFAR-SOR) detector. In yet another embodiment, the constant false alarm rate detector includes a constant false alarm rate ratio summation (CFAR-ROS) detector.

[0009] In some implementations, the first burst detector uses a signal-to-noise ratio estimate to analyze the physical structure of the received digital signal. In some implementations, the first burst detector uses a total power estimate to analyze the physical structure of the received digital signal.

[0010] In some embodiments, the first burst detector analyzes the physical structure of the received digital signal by estimating the probability of a burst in the received digital signal. In another embodiment, the first burst indicator corresponds to the estimated probability of a burst in the received digital signal. In yet another embodiment, the receiver further includes an iterative decoder configured to decode the received digitized signal by iteratively processing the received digital signal to generate a decoded signal, the behavior of which is influenced by the first burst indicator. In yet another embodiment, the first burst indicator indicates the presence of a burst in the received digital signal in response to an estimated probability greater than a first value, and indicates the absence of a burst in response to an estimated probability less than a first value. In yet another embodiment, the first value is based on the target false alarm probability. In yet another embodiment, the first burst indicator indicates the presence of a burst in the received digital signal in response to an estimated probability greater than a first value, indicates the absence of a burst in response to an estimated probability less than a second value, and indicates that a burst is indeterminate in response to an estimated probability between the first and second values. In another embodiment, the receiver further includes an iterative decoder configured to decode the received digitized signal by iteratively processing the received digitized signal to generate a decoded signal, wherein the number of iterations is set to a minimum iteration value in response to a first indicator indicating the absence of a burst, the number of iterations is set to a maximum iteration value in response to a first indicator indicating the presence of a burst, and the number of iterations is set to an intermediate iteration value between the minimum and maximum iteration values ​​in response to a first indicator indicating that the burst is indeterminate.

[0011] In some implementations, the second burst detector analyzes the information structure of the decoded signal by analyzing the total power estimate of the received digital signal to generate a second burst indicator. In some implementations, the second burst detector analyzes the information structure of the decoded signal by analyzing the signal-to-noise ratio (SNR) of the received digital signal to generate a second burst indicator. In some implementations, the second burst detector analyzes the information structure of the decoded signal by analyzing the Q2 and I2 values ​​of the decoded signal to generate a second burst indicator. In some implementations, the second burst detector analyzes the information structure of the decoded signal by analyzing decoder error parameters associated with the decoded signal to generate a second burst indicator.

[0012] This disclosure relates to a method for determining the presence of a burst in a communication system. The method includes receiving a digitized signal transmitted through a channel. The method includes using a first burst detector to generate a first burst indicator by analyzing the physical structure of the received digitized signal to determine whether a burst exists in the received digitized signal. The method also includes using a second burst detector to generate a second burst indicator by analyzing the information structure of a decoded signal corresponding to the received digitized signal to determine whether a burst exists in the received digitized signal.

[0013] In some embodiments, the method further includes decoding the received digitized signal by iteratively processing the received digital signal to generate a decoded signal, the number of iterations being influenced by a first burst indicator. In another embodiment, decoding and generating the first burst indicator occur at least partially in parallel. In yet another embodiment, if the first burst indicator indicates that there is no burst in the received digital signal, the number of iterations is limited to a minimum number of iterations, and if the burst indicator indicates that there is a burst in the received digital signal, the number of iterations is limited to a maximum number of iterations, wherein the maximum number of iterations is greater than the minimum number of iterations. In yet another embodiment, the response to the first burst indicator indicating a burst in the received digital signal is indeterminate, and the number of iterations is between the minimum and maximum number of iterations. In yet another embodiment, the method further includes estimating the probability that a burst exists in the received digital signal, and the number of iterations is influenced by the estimated probability.

[0014] In some embodiments, data-assisted analysis based on known pilot symbols is used to analyze the physical structure of the received digital signal. In another embodiment, the known pilot symbols include the buffer code of the received digital signal. In yet another embodiment, the Neyman-Pearson generalized likelihood ratio test (NP-GLRT) is used to analyze the physical structure of the received digital signal. In yet another embodiment, a constant false alarm rate (CFAR) detector is used to analyze the physical structure of the received digital signal. In yet another embodiment, the CFAR detector includes a constant false alarm rate ratio summation (CFAR-SOR) detector. In yet another embodiment, the CFAR detector includes a constant false alarm rate ratio summation (CFAR-ROS) detector.

[0015] In some implementations, a signal-to-noise ratio (SNR) estimate is used to analyze the physical structure of the received digital signal. In other implementations, a total power estimate is used to analyze the physical structure of the received digital signal.

[0016] In some implementations, the physical structure of the received digital signal is analyzed by estimating the probability of a burst in the received digital signal. In another implementation, a first burst indicator corresponds to the estimated probability of a burst in the received digital signal. In yet another implementation, the method further includes decoding the received digitized signal by iteratively processing the received digital signal to generate a decoded signal, the decoding being influenced by the first burst indicator. In yet another implementation, the first burst indicator indicates the presence of a burst in the received digital signal in response to an estimated probability greater than a first value, and indicates the absence of a burst in response to an estimated probability less than a first value. In yet another implementation, the first value is based on a target false alarm probability. In yet another implementation, the first burst indicator indicates the presence of a burst in the received digital signal in response to an estimated probability greater than a first value, indicates the absence of a burst in response to an estimated probability less than a second value, and indicates that a burst is indeterminate in response to an estimated probability between the first and second values. In another embodiment, the method further includes decoding the received digitized signal by iteratively processing the received digitized signal to generate a decoded signal, wherein the number of iterations is set to a minimum iteration value in response to a first indicator indicating the absence of a burst, the number of iterations is set to a maximum iteration value in response to a first indicator indicating the presence of a burst, and the number of iterations is set to an intermediate iteration value between the minimum and maximum iteration values ​​in response to a first indicator indicating that the burst is indeterminate.

[0017] In some implementations, the total power estimate of the received digital signal is analyzed to analyze the information structure of the decoded signal to generate a second burst indicator. In some implementations, the signal-to-noise ratio (SNR) of the received digital signal is analyzed to analyze the information structure of the decoded signal to generate a second burst indicator. In some implementations, the Q2 and I2 values ​​of the decoded signal are analyzed to analyze the information structure of the decoded signal to generate a second burst indicator. In some implementations, decoder error parameters associated with the decoded signal are analyzed to analyze the information structure of the decoded signal to generate a second burst indicator.

[0018] For the purpose of summarizing this disclosure, certain aspects, advantages, and novel features have been described herein. It should be understood that not all such advantages can be realized according to any particular embodiment. Therefore, the disclosed embodiments may be implemented in such a way that one or more advantages as taught herein are achieved or optimized, without necessarily achieving other advantages as may be taught or suggested herein. Attached Figure Description

[0019] For illustrative purposes, various embodiments are depicted in the accompanying drawings, and these various embodiments should in no way be construed as limiting the scope of this disclosure. Furthermore, various features of the different disclosed embodiments may be combined to form additional embodiments that are part of this disclosure.

[0020] Figure 1 An illustration of an exemplary satellite communication network is shown.

[0021] Figure 2A , Figure 2B and Figure 2C It shows according to Figure 1 Examples of resource allocation scheduling, timetable scheduling, and launch bursts in satellite communication networks.

[0022] Figure 3 An exemplary communication system with a receiver is shown, the receiver being configured to determine when a burst is absent and when a burst is present in a transmission from a user terminal.

[0023] Figure 4 An exemplary receiver configured to distinguish between data bursts and selective non-emission of data is shown.

[0024] Figure 5A and Figure 5B An example of a structure for receiving signals is shown.

[0025] Figure 6 Another exemplary receiver configured to distinguish between data bursts and selective non-emission of data is shown.

[0026] Figure 7 A flowchart of an exemplary method for detecting bursts in transmitted signals in a communication network is shown.

[0027] Figure 8 A block diagram of an exemplary receiver configured to use a two-stage burst detector to detect bursts in a transmit channel is shown. Detailed Implementation

[0028] The headings provided herein (if any) are for convenience only and do not necessarily affect the scope or meaning of the subject matter protected by the claims.

[0029] Overview

[0030] Figure 1An illustration of an exemplary satellite communication network 100 is shown. The satellite communication network 100 includes a satellite network 140 that communicatively couples multiple user terminals 110a, 110b and a gateway routing device 150 to each other and to a network (such as the Internet 160). The satellite communication network 100 includes a scheduler 170 configured to authorize resource allocation to user terminals 110a, 110b. The satellite communication network 100 includes a satellite transceiver 130 configured to transmit and receive signals via satellite 105. The satellite communication network 100 includes a receiver 180 configured to process and decode modulated signals received from user terminals 110a, 110b via the satellite transceiver 130. As described herein, the receiver 180 includes two burst detectors that operate on the received signals to identify when a burst is present or absent at the user terminals; a first burst detector is configured to analyze the physical structure of the received signals, and a second burst detector is configured to analyze the informational structure of the received signals. As used herein, the term “burst” may be used to refer to a group of data packets in a received signal transmitted by a user terminal and / or one or more data packets in a modulated data signal.

[0031] In satellite communication network 100, improving or optimizing the use of transmit power on the return link is advantageous. This is particularly relevant to high-throughput broadband satellite systems such as satellite communication network 100. In such a satellite communication network 100, the return link transponder gain can be variable and may be difficult to control precisely. Furthermore, the return link downlink power is a major contributor to return link capacity. The return link power profile is an aggregated representation of multiple uncoordinated and independent transmissions from user terminals (UTs). Resource allocation on the return link is typically determined in advance by the scheduler based on the aggregated demands of multiple UTs. However, depending on the transient buffer state, UTs may not fully utilize the allocated allocation, resulting in variations in the overall return link power profile. In MF-TDMA systems with adaptive beamforming, for example, return link packets may interfere with other packets transmitted at the same time-frequency resource, regardless of the distance between their transmitters. Therefore, reducing or eliminating unnecessary transmissions from UTs is beneficial. This will improve network resource utilization and power usage.

[0032] For example, a user terminal may receive an allocation grant of a specific size (such as 32 bytes). If the user terminal only has 20 bytes to send, it will transmit those 20 bytes along with 12 bytes of padding, which may be referred to as padding bytes. Therefore, in this case, the burst is partially padded. On the other hand, if the user terminal has no data to send, it may transmit a pseudo-burst containing a predetermined data format. A pseudo-burst may contain an 8-byte generic MAC header, with the remaining 24 bytes padded with 0xF. Therefore, in this case, the burst contains no actual data and is called a pseudo-burst. Although schedulers and allocation grants are discussed in this disclosure, it should be understood that a receiver may use the disclosed systems and methods to determine whether a burst exists or not in any implementation where the terminal sends a burst to the receiver.

[0033] False bursts can be particularly problematic in some communication systems, such as satellite communication network 100. For example, due at least in part to the relatively large propagation delay between the satellite and the terrestrial network, scheduler 170 may allocate more grants than a user terminal would request based on its current buffer state. This is because the current buffer state may not reflect future traffic demands. Since each grant request requires traversing at least one pair of terrestrial-satellite hops, and the response from scheduler 170 to user terminals 110a, 110b requires traversing the same path in reverse, there is an incentive to over-allocate resources to counteract the relatively high latency in satellite communication network 100. If a user terminal has no data to transmit in these additional grants, it will typically launch a false burst. Furthermore, false bursts can hinder the use of contention. For example, contention allows multiple terminals to send bursts; if more than one terminal sends a burst in the same resource, a conflict occurs, and the terminal must retransmit. In systems with low transmission probability (e.g., low-rate sensor networks), retransmission is a viable option. However, if a terminal repeatedly sends false bursts, the likelihood of bursts constantly colliding is much higher.

[0034] Eliminating spurious bursts transmitted by user terminals in communication systems (such as satellite communication system 100) would be beneficial. Eliminating or reducing spurious bursts is advantageous because they waste transmit power on the return link. Furthermore, receiver 180 is configured to handle both spurious and regular bursts. Therefore, eliminating or reducing the number of spurious bursts to improve receiver performance would be advantageous. However, in typical communication systems, user terminals need to transmit bursts when they have the opportunity. If a user terminal has no data to transmit, it instead transmits spurious bursts.

[0035] Therefore, this paper describes systems and methods that enable user terminals to eliminate or reduce the number of spurious bursts they transmit. These systems and methods use two burst detectors that operate on different aspects of a signal to identify when a burst is absent. A first burst detector analyzes the physical structure of the signal to generate a first burst indicator indicating the presence or absence of a burst. A second burst detector analyzes the information structure of the signal to generate a second burst indicator indicating the presence or absence of a burst. The first burst indicator can be used to control the operation of a signal decoder that decodes the received signal. The second burst detector analyzes the output from the signal decoder to determine the second burst indicator. In other words, the first burst detector can be implemented before decoding the received signal to provide a first estimate related to the presence or absence of a burst. This first estimate can then be used to limit the amount of processing performed by the signal decoder. When there is no burst in the signal, this reduces or eliminates processing cycles that might otherwise be wasted on decoding noise (e.g., in the absence of a burst).

[0036] As described herein, the disclosed systems and methods enable the elimination or reduction of spurious bursts from user terminals. Spurious bursts are generally easy to identify, but require processing and decoding before being discarded. On the other hand, it may be difficult to distinguish the absence of bursts. Therefore, this paper describes systems and methods that advantageously distinguish between selective non-transmission (absence of bursts) and transmission errors (absence of bursts but unsuccessful decoding) from user terminals. Utilizing this capability, communication systems can configure user terminals not to transmit data when they have no data to transmit, rather than requiring user terminals to transmit spurious bursts. This improves the efficiency of the communication system and reduces the average power profile of the communication system because user terminals can be configured to transmit only when they have data. Another benefit is that the disclosed burst decoder does not need to run for every anticipated burst. Instead, the disclosed burst detector can run for existing bursts, thereby reducing the required computational resources. Another benefit is reduced interference to other return link transmissions on adjacent beams.

[0037] return Figure 1 Satellite communication network 100 can utilize various network architectures including space and ground segments. For example, the space segment may include one or more satellites, while the ground segment may include one or more satellite user terminals, gateway terminals, network operations centers (NOCs), satellite and gateway terminal command centers, etc. For clarity, some of these elements are not shown in the figure. Satellite network 140 may include one or more geostationary orbit (GEO), one or more medium Earth orbit (MEO) satellites, and / or one or more low Earth orbit (LEO) satellites.

[0038] User terminals 110a and 110b may include routers and may be configured to receive data to be routed through satellite communication network 100. The user terminals include any type of consumer location device (e.g., telephone, modem, router, computer, set-top box, etc.).

[0039] User terminals 110a and 110b are configured to route data to satellite network 140 (via corresponding client satellite transceivers 120a and 120b). Satellite network 140 includes a forward link for transmitting information from gateway routing device 150 to user terminals 110a and 110b, and a return link for transmitting information from user terminals 110a and 110b to gateway routing device 150. The forward link includes a transmission path starting from gateway routing device 150, through gateway satellite transceiver 130, via satellite uplink channel through satellite 105, via satellite downlink channel to client satellite transceivers 120a and 120b, and to user terminals 110a and 110b. The return link includes a transmission path starting from client satellite transceivers 120a and 120b, via satellite uplink channel to satellite 105, via satellite downlink channel to gateway satellite transceiver 130, and to gateway routing device 150. Each transmission channel can utilize multiple satellites and transceivers.

[0040] Figures 2A to 2C It shows according to Figure 1 Examples of resource scheduling schedules and launch bursts in a satellite communication network 100. Figure 2A The illustration shows that each of user terminals 110a and 110b requests a return link grant 112a or 112b on the satellite network from scheduler 170 via gateway routing device 150. User terminals 110a and 110b request return link resources from scheduler 170 based on buffer size, QoS parameters, and other flow parameters.

[0041] Figure 2B The diagram illustrates how scheduler 170 allocates resource blocks 230 (time-frequency resources) in time slot 220 to serve bandwidth requests from user terminals 110a and 110b. These allocations are based on the demands from user terminals 110a and 110b. The allocations may be transmitted to user terminals 110a and 110b as a table (e.g., RL-MAP) via broadcast, multicast, or unicast messages through gateway routing device 150.

[0042] In some implementations, scheduler 170 may utilize a Demand-Based Multiple Access (DAMA) scheduling model, an Enhanced Mobile Satellite Service (EMSS) scheduling model, and / or other scheduling techniques. In response to receiving a request for bandwidth allocation from user terminals 110a, 110b, scheduler 170 analyzes the request, network status, network congestion, previous requests, similar requests, etc., to determine a scheduling schedule for return link bandwidth. In some implementations, scheduler 170 is configured to generate the scheduling schedule based on a prediction or estimate of the actual bandwidth required to fulfill the request.

[0043] Figure 2C User terminals 110a and 110b are shown transmitting data 114a and 114b from their buffers according to time-frequency resources allocated by scheduler 170. User terminals 110a and 110b transmit the data to gateway routing device 150 via a return link through satellite network 140. User terminals 110a and 110b may use all or part of the allocated resource blocks, or, if they have no data to transmit for the allocated time-frequency resources, they may choose not to transmit a burst. Receiver 180 is configured to analyze the data transmitted by user terminals 110a and 110b. As disclosed herein, receiver 180 includes a burst detector configured to distinguish between selective non-transmission of data (e.g., no burst corresponding to the allocated resource grant) and transmitted data (e.g., bursts that fill or partially fill the allocated resource grant), which may contain transmission errors (e.g., a burst transmitted for the allocated resource grant, but the burst contains problems).

[0044] Upon reaching gateway routing device 150, the data can then be routed to the Internet 160. Data from the Internet 160 can be transmitted from gateway routing device 150 to user terminals 110a and 110b via a forward link of satellite network 140. In some implementations, some or all of gateway routing device 150, receiver 180, and / or scheduler 170 may reside in a virtual device residing in a public or private computing cloud and / or be part of a distributed computing environment.

[0045] Figure 3 An exemplary communication system 300 with a receiver 380 is shown, the receiver being configured to determine when a burst is absent and when a burst is present in a transmission from a user terminal. The communication system 300 includes a network 340 configured to communicatively couple a plurality of user terminals 310 to the receiver 380 and the Internet 360 (or other suitable network). The communication system 300 includes features similar to... Figure 1 Gateway routing device 150 and gateway routing device 350. Communication system 300 includes similar... Figure 1 Scheduler 170 and scheduler 370.

[0046] The receiver 380 of the communication system 300 is configured to receive transmission bursts from the user terminal 310 via a network 340. The network 340 may be a terrestrial network, a satellite network, or a combination of terrestrial and satellite networks. The receiver 380 includes complementary burst detectors, as described in more detail herein, configured to determine whether a burst exists in a signal corresponding to an allocated resource grant. As described herein, the user terminal 310 may be configured to select not to transmit data for a specific resource grant allocation for a corresponding user terminal that has no data to transmit. In response, the receiver 380 may be configured to identify that no burst exists in the received signal corresponding to the specific resource grant allocation. Additionally, if the user terminal transmits a fully or partially filled burst for a resource grant allocation, the receiver 380 is configured to determine that a burst exists. If the signal received by the receiver 380 is faulty, the receiver 380 is configured to determine whether a burst does not exist or a burst exists but is faulty.

[0047] Exemplary receiver with a two-stage burst detector

[0048] Figure 4 An exemplary receiver 480 is shown, configured to distinguish between data bursts and selective non-emission of data. Receiver 480 can be... Figure 1 Satellite communication system 100 and / or Figure 3 The communication system 300 is implemented. Receiver 480 includes a first burst detector 482, an iterative decoder 484, a second burst detector 486, and a data aggregation 488. Data aggregation 488 accumulates the decoded bursts and arranges them in the correct order. For example, multiple bursts can be assigned to different user terminals, and in an MF-TDMA system, each return link burst can occupy a specific time interval within a time slot in the frequency channel. Correct ordering may include time sorting, MAC packetization, mapping to user and service flows, etc.

[0049] Receiver 480 is configured to receive digitized signals via a communication channel and implement a two-stage burst detector, comprising a first burst detector 482 and a second burst detector 486. The two-stage burst detector operates at the physical layer of the communication system. It analyzes both the physical and informational structures of the signal. The first burst detector 482 and the second burst detector 486 can operate serially or in parallel. The first burst detector 482 and the iterative decoder 484 can also operate serially or in parallel. In some embodiments, the communication channel is a return link channel in a satellite communication system.

[0050] A first burst detector 482 is configured to receive a digitized signal transmitted through a communication channel and generate a first burst indicator by analyzing the physical structure of the received digitized signal to determine whether a burst exists in the received digitized signal. In some embodiments, the first burst detector implements a signal detection algorithm to determine the presence of a burst, as described herein. The first burst detector 482 may generate a first burst indicator corresponding to the result of the analysis of the physical structure. In some embodiments, the first burst indicator is a binary result indicating the presence or absence of a burst. In some embodiments, the first burst indicator has multiple discrete values ​​or results. For example, the first burst indicator may indicate the presence of a burst, the absence of a burst, or that the burst is indeterminate. As another example, the first burst indicator may indicate a confidence level related to the presence of a burst (e.g., 0 corresponds to the absence of a burst, 1 corresponds to the presence of a burst, and discrete values ​​between these indicate various confidence levels regarding the presence of a burst). In various embodiments, the first burst indicator can be any suitable value and can be continuous. For example, the first burst indicator may correspond to an estimated probability of the presence of a burst in the digitized signal. As another example, the first burst indicator may correspond to a value derived from the analysis of the physical structure of the signal, such as an estimate of the signal-to-noise ratio.

[0051] The first burst detector 482 is configured to analyze all digitized signals received at the receiver. Conversely, in some embodiments, the second burst detector 486 is configured to analyze signals for which the first burst detector 482 determines a burst exists. In such embodiments, the second burst detector 486 may be configured not to analyze signals for which the first burst detector 482 determines no burst exists.

[0052] The first burst detector 482 is configured to act on a sample of each symbol burst after the signal is acquired at a specific time (and after despreading, if present in the system). In some embodiments, the first burst detector 482 uses a single estimator to determine whether a burst is present or absent in the signal, examples of which are described herein. In some specific embodiments, the described single estimator acts only on the known buffer code for each burst, as described herein. In some embodiments, the first burst detector 482 uses an iterative algorithm to determine whether a burst is present or absent in the signal. The described iterative algorithm acts on all symbols of the burst, e.g., known buffer codes and unknown data symbols. In some embodiments, the iterative algorithm may involve determining relevant signal parameters, such as signal-to-noise ratio estimates and / or signal power estimates.

[0053] As an example, the first burst detector 482 can operate on I / Q (in-phase / quadrature) samples. The first burst detector 482 analyzes the IQ samples to determine the characteristics of the signal, at least in part, based on the physical structure of the signal. The IQ samples provide a representation of the actual signal, allowing the first burst detector 482 to examine the signal and noise (e.g., the amplitude of the signal and noise over time in a complex space). In some embodiments, the first burst detector 482 analyzes digitized time-domain samples of the received signal.

[0054] The physical structure of the signal refers to the modulated waveform that carries encoded information bits from the transmitter to the receiver 480 via a physical channel (e.g., typically a satellite link or any transmission channel). In some implementations, the physical waveform constitutes a multi-frequency time-division multiple access (MF-TDMA) "burst" with a specific structure. This structure can be a specific pattern of buffer codes and data symbols with a predetermined number of symbols, where the a priori positions and contents of the buffer codes are known to the receiver. The data symbols come from a known finite set of choices (e.g., digital constellations, such as binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), etc.), but the receiver 480 does not know which specific symbol was transmitted a priori. A first burst detector 482 is configured to analyze the received signal, which has a known burst structure but does not know the unknown data symbols. Therefore, the first burst detector 482 is configured to analyze the physical structure of the signal without needing to analyze the data symbols (e.g., the contents of the data symbols).

[0055] The first burst detector 482 is programmed with knowledge of timing to capture samples spanning the burst duration. In some embodiments, the first burst detector 482 is configured to estimate timing, frequency, and power. In some embodiments, the first burst detector 482 is configured to receive digital samples of the received signal at the symbol rate of the signal.

[0056] The first burst detector 482 is configured to analyze the received signal using data-assisted analysis based on known pilot symbols. In some embodiments, the known pilot symbols include the buffer code of the received digital signal.

[0057] To better illustrate the structure of the received signal, Figure 5A An exemplary burst 500a is shown, comprising a preamble 512 and multiple codewords 514a-514n. Each codeword 514 includes periodic and repetitive data 522 and a buffer code 524. Each data 522 includes a certain number of symbols (N). b Each buffer code 524 includes another number of symbols (N symbols). a(symbols). Therefore, the basic structure of a burst is a preamble, followed by a repeating sequence of data symbols and buffer codes, where each data symbol block has the same length and each buffer code block has the same length.

[0058] The received burst 500 is expected to have a small frequency error, resulting in an unknown phase. The buffer code segment 524 is divided such that the phase in each buffer code is constant and independent of the phases in adjacent buffer codes. The frequency error is so small that the phase on each buffer code is assumed to be constant. A small frequency error may lead to a phase error that increases over time. For a sufficiently small frequency error, it can be assumed that the phase errors on adjacent buffer codes are the same, and that the phase errors on groups of buffer codes that are significantly separated in time are independent. Furthermore, it is assumed that the magnitude of the channel gain is constant over the burst.

[0059] The nth sample in the m-th buffer set can be represented as:

[0060]

[0061] For the slow code 524, x m，n It is known, and the noise w m，n It is unknown, but is assumed to be additive white Gaussian noise (AWGN). The channel magnitude and phase of each buffer code are assumed to be unknown. The first burst detector 482 is configured to act on the samples after signal processing to remove modulation.

[0062]

[0063] Signals can have more general structures, such as Figure 5B As shown in the figure, the exemplary burst 500b includes a preamble 512 and multiple codewords 514a-514n. Each codeword 514 includes repeating pattern data 522a-522k and buffer codes 524a-524k. Each data 522a-522k includes a certain number of symbols (N). b1 N b2 ... N bk Each buffer code 524 includes another number of symbols (N symbols). a1 N a2 ... N ak (Symbols). Each segment can have a different number of symbols. The pattern or structure can be general, and because it is known to the detector, the signal structure can be analyzed.

[0064] Therefore, the first burst detector 482 is configured to analyze the physical structure of the signal. The first burst detector 482 may use variations of well-known algorithms suitable for this particular purpose. The first burst detector 482 may perform this analysis at least in part due to the periodicity of the structure of the preamble and the received signal at certain locations.

[0065] The first burst detector 482 implements elements of signal detection theory to determine the presence or absence of a burst and generate a first burst indicator. The first burst detector is configured to decide between two hypotheses: H0 (null hypothesis), which indicates that no burst was received; and H1 (alternative hypothesis), which indicates that a burst was received. In detection theory, detectors typically have two types of error: Pmd, or the probability of missed detection (sometimes called Type I error or specificity), and Pfa, or the probability of false alarms (sometimes called Type II error or sensitivity). It is desirable for the receiver 480 to avoid missing legitimate bursts, making it advantageous to try to keep the probability of missed detection (Pmd) as low as possible. However, this leads to an increase in the probability of false alarms (Pfa). An increase in Pfa results in more false bursts being passed to the iterative decoder 484 for decoding. Advantageously, the second burst detector 486 is configured to reduce the number of false signals (or signals that do not contain actual bursts). This is done by adding complementary analysis of the information structure of the signal, thereby reducing or eliminating false bursts from the data pipeline after the second burst detector 486.

[0066] Because it is not desirable to miss the detection of valid bursts, it is advantageous to set Pmd as low as possible. In some embodiments, Pmd is set to less than or equal to about 1e-4 or less than or equal to about 1e-5. Therefore, Pfa is higher. In some embodiments, Pfa is about 0.01 or about 1e-3. Therefore, about 1% of spurious bursts are passed to decoder 484 for processing, which means that about 1% of temporal noise is forwarded to decoder 484 for processing. In such cases, decoder 484 may fail and output a burst error indicator. This can be used by a second burst detector 486 to determine that no burst exists in the signal. Burst errors may occur for the following reasons: (a) a burst actually exists, but the SNR is poor and decoder 484 fails, or (b) no burst exists, but first burst detector 482 indicates that a burst exists (e.g., a false alarm). Because Pfa is relatively high, receiver 480 includes a second burst detector 486 to improve decoder error statistics or to identify signals that are indicated to have a burst when no burst actually exists.

[0067] In some implementations, the first burst detector 482 is configured to estimate the probability that a burst exists in the received digital signal. In various implementations, the number of iterations of the iterative decoder 484 is influenced by the estimated probability. In some specific implementations, the first burst indicator corresponds to the estimated probability that a burst exists in the received digital signal. In various specific implementations, the first burst detector 482 utilizes a threshold to compare with the estimated probability. Above a high probability, the first burst indicator indicates the presence of a burst; below a low probability, the first burst indicator indicates the absence of a burst; and between high and low probabilities, the first burst indicator indicates uncertainty about the presence of a burst. The threshold indicating the presence of a burst may be related to the target false alarm probability. In some implementations, the number of iterations used by the decoder 484 for decoding is influenced by the first burst indicator. In some specific implementations, such as those in which the first burst indicator includes an estimate of signal parameters (e.g., SNR or total power) or an estimate of the probability of a burst existing, the number of iterations may scale with or otherwise correspond to the first burst indicator. It may be advantageous to limit the processing cycles spent on signals that do not contain bursts or are unlikely to contain bursts.

[0068] In some implementations, the first burst detector can use a likelihood ratio test (LRT) to determine the presence of a burst in the received signal. Specifically, a theorem known as the Neyman-Pearson theorem can be used to minimize Pmd, which is equivalent to maximizing the detection probability of the signal. In this theorem, for a given Pfa, H1 is determined if:

[0069]

[0070] Where z is the number of samples used by the detector, and γ is a threshold that depends on Pfa. This method is called the likelihood ratio test (LRT) and has been shown to be optimal in minimizing Pmd for a given Pfa.

[0071] However, difficulties may arise, at least in part, due to the sample z used by the first burst detector 482, which depends on some parameters that are unknown prior. Examples of such parameters include, for instance, frequency offset, phase offset, channel gain, noise variance, symbol value, etc. Advantageously, the generalized LRT (GLRT) method uses the same techniques as LRT, except that the unknown parameters are replaced with the maximum probable (ML) estimates of those parameters.

[0072] Therefore, the first burst detector 482 can use the NP-GLRT method. This method involves starting with the LRT modulation described above and applying it to specific values ​​determined for analysis (e.g., Pmd less than a first constant c1 and Pfa less than a second constant c2, where c2>c1):

[0073]

[0074] In LRT modulation, there are unknown parameters (e.g., σ). 2 、|h|、θ m Therefore, the ML estimates of these parameters can be determined and used to replace those missing elements in the LRT modulation. Then, Pfa and Pmd can be determined for various values ​​of the threshold γ. The ML estimates of the parameters can be closed-form mathematical expressions, relatively simple to implement, and can be obtained using only known burst codes.

[0075]

[0076]

[0077]

[0078] Constant False Alarm Ratio (CFAR) is another detection technique that can be used by the first burst detector 482. CFAR and NP-GLT are configured to operate on a known buffer code for each burst. The CFAR technique includes CFAR-Ratio Sum (CFAR-SOR):

[0079]

[0080] And CFAR-total ratio (CFAR-ROS):

[0081]

[0082] Either of these can be implemented in the first burst detector 482. Therefore, the first burst detector 482 is configured to analyze the physical structure of the received digital signal using the Neyman-Pearson generalized likelihood ratio test (NP-GLRT), and the first burst detector is configured to analyze the physical structure of the received digital signal using a constant false alarm rate (CFAR) detector, wherein the constant false alarm rate detector includes a constant false alarm rate ratio summation (CFAR-SOR) detector or a constant false alarm rate ratio summation (CFAR-ROS) detector.

[0083] In some implementations, the first burst detector 482 is configured to use a signal-to-noise ratio (SNR) estimate and / or a total power estimate. In some specific implementations, the first burst detector 482 uses an iterative method to determine these parameters. For example, the first burst detector 482 uses expected-step and maximize-step (EM-based) SNR estimates. These techniques represent non-data-aided iterative estimators. The single-shot estimator techniques described above (e.g., NP-GLRT and CFAR) can be considered data-aided techniques because they rely on the use of known pilot symbols (e.g., buffer codes).

[0084] In some implementations, the first burst detector 482 provides a multi-stage decision region. For example, based on the output of the analysis (e.g., the estimated SNR), the first burst detector 482 generates a first burst indicator based on a threshold. The threshold may be based on the probability of a false alarm and / or a missed detection. In this example, if the estimated signal-to-noise ratio (SNR) is greater than or equal to a high threshold, the first burst indicator indicates the presence of a burst, and in response, the iterative decoder 484 may perform a maximum number of iterations (e.g., 100 iterations) to decode the signal. If the estimated SNR is less than or equal to a low threshold, the first burst indicator indicates the absence of a burst, and in response, the iterative decoder 484 may perform a minimum number of iterations (e.g., 1 iteration) to decode the signal. If the estimated SNR is between the high and low thresholds, the first burst indicator indicates that the burst is uncertain, and in response, the iterative decoder 484 may perform an number of iterations between the minimum and maximum number (e.g., 40 iterations) to decode the signal. In cases where a burst is uncertain, as determined by the first burst detector 482, the second burst detector 486 advantageously provides a second burst indicator that can improve the result or increase the probability that the determination of the existence of a burst is closer to 1.

[0085] The second burst detector 486 is configured to generate a second burst indicator by analyzing the information structure of the decoded signal corresponding to the received digital signal to determine whether a burst exists in the received digital signal. The information structure of the signal may relate to the data symbols within the burst. The data symbols within the burst carry encoded information transmitted from the transmitter. The decoder 484 at the receiver 480 determines the information content by iteratively decoding the encoded bits. This process may be time-consuming and computationally complex. The first burst detector 482 is unaware of the information content, but the decoder 484 can make the second burst detector 486 aware of the information content. For example, the decoder 484 may send metrics (e.g., log-likelihood ratio) about (a) hard decisions (e.g., whether decoding of the burst is successful) or (b) soft decisions, which can provide the second burst detector 486 with additional information about bursts that were not available prior to the decoding operation.

[0086] The information structure of the signal may include the total power estimate, the SNR estimate, and the Q of the decoded signal. 2 Value, I of the decoded signal 2 Values, decoder error parameters, etc. The second burst detector 486 uses the output of the decoder 484 to determine the second burst indicator. These outputs may include estimates such as total power, SNR, I... 2 Q 2 This improves the determination of the presence of bursts. Therefore, the second burst detector 486 can be configured to distinguish between genuine burst errors and false alarm burst errors. The second burst detector 486 is configured to act on the output indicator of the iterative decoder and examine the information content of the signal and how it matches a valid signal.

[0087] The analysis of the physical structure of a signal is limited by the general system design, but the information structure depends on the specific transmitted signal and therefore provides more information. However, determining the information structure of a signal requires more processing (e.g., decoder 484 must decode the signal). Therefore, receiver 480 includes a two-stage detector, where a first burst indicator 482 operates on the physical structure of the signal, which may produce relatively inaccurate results, but generally eliminates a large amount of unnecessary processing by eliminating a large number of signals where bursts do not exist. Then, a second burst detector 486 can rely on more computationally complex and rigorous techniques to improve the determination of the presence of bursts in the signal. Thus, the first stage reduces computational complexity, and the second stage helps to refine decision-making and accurately manage performance metrics and diagnostics. For example, the first burst detector 482 determines whether a burst exists given a received sample, and the second burst detector 486 determines whether a burst exists given a total power estimate (e.g.) and the fact that the decoder indicates burst error.

[0088] The second burst detector 486 relies on the decoder 484 to complete its iterations (which may be influenced by the output of the first burst detector 482, as described herein) and provides hard / soft decisions regarding bursts. The second burst detector 486 does not operate on samples, but rather on data such as the total power measurement estimate as the output of the decoder 484 and the burst error metric as the output of the decoder 484. If the decoder 484 fails, it sends a signal to indicate a burst failure, which serves as the input to the second burst detector 486. Therefore, the second burst detector can be used to eliminate burst errors caused by the false alarm rate of the NP-GLRT detector (the first burst detector) or by the false alarm rate of the first burst detector generated by the algorithm used (e.g., NP-GLRT).

[0089] In some implementations, for example, a second burst detector 486 is configured to monitor noise power measurements. Noise power measurements can be monitored for a signal or a user terminal with similar characteristics (including signals for similar carriers in a return carrier group). An estimate of the noise power of the signal or the user terminal with similar characteristics can be determined by measuring the noise power over time. The second burst detector 486 can compare or estimate the total power measurement of the signal and compare it with the noise power measurement. If the total power measurement is a threshold amount higher than the noise power measurement, the second burst detector 486 can determine that a burst exists; otherwise, the second burst detector 486 can determine that no burst exists.

[0090] The iterative decoder 484 is configured to decode the received digitized signal by iteratively processing the received digital signal to generate a decoded signal, the number of iterations being influenced by a first burst indicator generated by the first burst detector. The iterative decoder 484 is configured to operate serially or in parallel with the first burst detector 482.

[0091] In some implementations, if a first burst indicator indicates that no burst is present in the received digital signal, the number of iterations is limited to a minimum number of iterations, and if a burst indicator indicates that a burst is present in the received digital signal, the number of iterations is limited to a maximum number of iterations, where the maximum number of iterations is greater than the minimum number of iterations. In some implementations, the response to the first burst indicator indicating a burst in the received digital signal is indeterminate, and the number of iterations falls between the minimum and maximum number of iterations. In some implementations, the first burst detector 482 estimates the probability that a burst is present in the received digital signal, and the number of iterations is influenced by the estimated probability. In some implementations, the decoder 484 is configured to send a signal to the second burst detector 486 indicating that no burst has been received (this may be based on the first burst indicator). In some implementations, the iteration count of the decoder 484 is based on the output of the first burst detector 482. In some implementations, the number of iterations may be a stepped region (e.g., an interval or decision region) associated with the first burst indicator, or a single region (e.g., 40 iterations if the burst is indeterminate), or a value scaled with the continuous output of the first burst detector 482 (e.g., the first burst indicator may be a value between 0 and 1, and the number of iterations scales with that value).

[0092] Figure 6 Another exemplary receiver 680 configured to distinguish between data bursts and selective non-emission of data is shown. Receiver 680 is implemented as a two-stage burst detector including a first burst detector 682 and a second burst detector 686. The first burst detector 682 is similar to that described herein with respect to... Figure 4The first burst detector 482 is described above. For example, the first burst detector 682 is configured to receive a digitized signal transmitted through a channel and generate a first burst indicator by analyzing the physical structure of the received digitized signal to determine whether a burst exists in the received digitized signal. Additionally, the second burst detector 686 is similar to that described herein with respect to... Figure 4 The second burst detector 486 is described above. For example, the second burst detector 686 is configured to generate a second burst indicator by analyzing the information structure of the decoded signal corresponding to the received digital signal to determine whether a burst exists in the received digital signal. In some embodiments, the receiver 680 may be configured to interact with a signal decoder separate from the receiver 680. This allows the receiver 680 to be implemented with any suitable signal decoder, such as any iterative signal decoder described herein. In some embodiments, the decoder is integrated with the receiver 680.

[0093] Receiver 680 is configured to receive a digitized signal, which may include, for example, I / Q samples. A first burst detector 682 analyzes the digitized signal (including its physical structure) and generates a first burst indicator. The digitized signal and the first burst indicator are passed to a decoder for decoding. The decoder may be part of or separate from receiver 680. Receiver 680 is configured to receive data from the decoder in a second burst detector 686. The second burst detector 686 analyzes the decoder output (including the information structure of the digitized signal) and generates a second burst indicator. The second burst indicator may be sent to other systems or used by other components of receiver 680.

[0094] Exemplary method for detecting bursts using a two-stage burst detector

[0095] Figure 7 A flowchart of an exemplary method 700 for detecting bursts in transmitted signals in a communication network is shown. Method 700 may be referenced herein. Figures 1 to 4 and Figure 6 The method 700 is performed in any of the receivers described herein. For ease of description, method 700 will be described as being performed by a receiver. This should not be construed as limiting the scope of this disclosure. Rather, any step or part of method 700 may be performed by any component or combination of components of the communication network described herein.

[0096] In block 705, the receiver receives a digitized signal. The digitized signal may include IQ samples. The digitized signal may be received via a transmit channel that may include a return link channel.

[0097] In block 710, the receiver analyzes the physical structure of the digitized signal to generate a first burst indicator. The analysis of the physical structure may be based on a single estimator, such as NP-GLRT or CFAR, or on an iterative estimator, such as an EM-based SNR estimator. The physical structure of the signal may include a known pilot signal, such as a buffer code. The physical structure of the signal may include a periodic structure of data and buffer codes within a codeword following a preamble. The first burst indicator may indicate the presence or absence of a burst in the digitized signal. In some embodiments, the first burst indicator indicates a discrete value with two or more values ​​corresponding to the degree of certainty of the presence, absence, or presence of a burst in the digitized signal. In some embodiments, the first burst indicator corresponds to the probability of a burst. In various embodiments, the first burst indicator corresponds to an estimated characteristic of the digitized signal (e.g., SNR, total power, etc.).

[0098] In block 715, the receiver iteratively decodes the digitized signal. The number of iterations may be influenced by the results of the analysis in block 710. The receiver may generate an output based on the iterative decoding process. The output may include total signal power, SNR, I^2 and / or Q^2 values, burst error indicator, etc.

[0099] In block 720, the receiver analyzes the information structure of the digitized signal to generate a second burst indicator. The information structure may include the output provided in block 715. The information structure of the digitized and decoded signal may include a total power estimate, an SNR estimate, etc. Analysis of the information structure improves the results of the analysis performed in block 710.

[0100] In some implementations, some steps of method 700 may be performed in parallel or simultaneously, and not necessarily sequentially. For example, the processing in blocks 710 and 715 may occur sequentially or in parallel. In some implementations, the first burst detector may complete the analysis of the physical structure (block 710) and determine the number of decoder iterations before the processing in block 715 can begin. This can advantageously reduce the computational complexity at the decoder. In various implementations, the decoder may begin its iteration while the first burst detector is still analyzing the signal. If the first burst detector determines that no burst exists, it may send an interrupt to the decoder to stop processing. This can advantageously reduce the overall latency of the system.

[0101] Additional Implementation Plan

[0102] Figure 8 A block diagram of an exemplary receiver 880 configured to detect bursts in a transmit channel using a two-stage burst detector is shown. Receiver 880 is configured to analyze the physical structure and informational structure of the signal to determine whether a burst is present or absent. Receiver 880 is similar to the references herein. Figures 1 to 4and Figure 6 The receiver described herein can be implemented in any communication system described herein. The receiver 880 can employ any method described herein for detecting and identifying bursts in transmitted signals, such as those referenced herein. Figure 7 The exemplary method 700 is described above.

[0103] Receiver 880 may include hardware, software, and / or firmware components for detecting bursts and decoding digital signals. Receiver 880 includes a data repository 881, one or more processors 883, one or more network interfaces 885, a first burst detector module 882, a decoder module 884, and a second burst detector module 886. Components of receiver 880 may communicate with each other, with external systems, and with other components of the network using a communication bus 889. Receiver 880 may be implemented using one or more computing devices. For example, receiver 880 may be implemented using a single computing device, multiple computing devices, a distributed computing environment, or the receiver may reside in a virtual device residing in a public or private computing cloud. In a distributed computing environment, one or more computing devices may be configured to provide modules 882, 884, and 886 to provide the described functionality.

[0104] Receiver 880 includes a first burst detector module 882 for analyzing the physical structure of the received digital signal to determine whether the signal contains bursts, as described herein. Receiver 880 includes a second burst detector module 886 for analyzing the information structure of the received digital signal to determine whether the decoded signal contains bursts, as described herein. Receiver 880 includes a decoder module 884 for decoding the received digital signal, as described herein. In some embodiments, decoder module 884 iteratively processes the received digital signal to decode it. In some embodiments, decoder module 884 is influenced by the output of the first burst detector module 882. In some embodiments, second burst detector module 886 uses information extracted or determined by decoder module 884 to determine whether bursts are present or absent in the received digital signal.

[0105] Receiver 880 includes one or more processors 883 configured to control the operation of modules 882, 884, 886 and data repository 881. The one or more processors 883 implement and utilize software modules, hardware components, and / or firmware elements configured to detect bursts in the transmitted signal and decode the transmitted signal. The one or more processors 883 may include any suitable computer processor, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other suitable microprocessor. The one or more processors 883 may include other computing components configured to interact with the various modules and data repository of receiver 880.

[0106] Receiver 880 includes a data repository 881 configured to store configuration data, analysis parameters, control commands, databases, algorithms, executable instructions (e.g., instructions for one or more processors 883), etc. Data repository 881 can be any suitable data storage device or combination of devices, including, but not limited to, random access memory, read-only memory, solid-state drives, hard disk drives, flash drives, bubble storage, etc.

[0107] This disclosure describes various features, none of which alone is solely responsible for the benefits described herein. It should be understood that the various features described herein can be combined, modified, or omitted, as will be apparent to those skilled in the art. Other combinations and sub-combinations besides those specifically described herein will be apparent to those skilled in the art and are intended to form part of this disclosure. Various methods are described herein in conjunction with various flowchart steps and / or stages. It should be understood that in many cases, certain steps and / or stages can be combined such that multiple steps and / or stages shown in the flowchart can be performed as a single step and / or stage. Additionally, certain steps and / or stages can be divided into additional sub-components for separate execution. In some cases, the order of steps and / or stages can be rearranged, and certain steps and / or stages can be omitted entirely. Furthermore, the methods described herein should be understood as open-ended, such that additional steps and / or stages shown and described herein can also be performed.

[0108] Some aspects of the systems and methods described herein can be advantageously implemented using, for example, computer software, hardware, firmware, or any combination of computer software, hardware, and firmware. Computer software may include computer-executable code stored on a computer-readable medium (e.g., a non-transitory computer-readable medium) that, when executed, performs the functions described herein. In some embodiments, the computer-executable code is executed by one or more general-purpose computer processors. As will be understood by those skilled in the art based on this disclosure, any feature or function that can be implemented using software that will execute on a general-purpose computer may also be implemented using different combinations of hardware, software, or firmware. For example, such modules may be implemented entirely in hardware using a combination of integrated circuits. Alternatively or otherwise, such features or functions may be implemented wholly or partially using a special-purpose computer designed to perform the specific functions described herein, rather than a general-purpose computer.

[0109] Multiple distributed computing devices can replace any single computing device described herein. In such distributed implementations, the functionality of a computing device is distributed (e.g., via a network), such that some functions are performed on each of the distributed computing devices.

[0110] Some implementation schemes may be described with reference to formulas, algorithms, and / or flowcharts. These methods can be implemented using computer program instructions executable on one or more computers. These methods can also be implemented individually as computer program products or as components of an apparatus or system. In this regard, each formula, algorithm, block, or step in the flowchart, and combinations thereof, can be implemented by hardware, firmware, and / or software that includes one or more computer program instructions embodied in computer-readable program code logic. It should be understood that any such computer program instructions can be loaded onto one or more computers (including, but not limited to, general-purpose or special-purpose computers, or other programmable processing devices) to create a machine such that the computer program instructions, which execute on the computer or other programmable processing device, implement the function specified in the formula, algorithm, and / or flowchart. It should also be understood that each formula, algorithm, and / or block in the flowchart illustration, and combinations thereof, can be implemented by a computer system based on special-purpose hardware or a combination of special-purpose hardware and computer-readable program code logic devices that perform the specified function or step.

[0111] Furthermore, computer program instructions (such as those embodied in computer-readable program code logic) may also be stored in a computer-readable storage medium (e.g., a non-transitory computer-readable medium) that can instruct one or more computers or other programmable processing devices to operate in a particular manner, such that the instructions stored in the computer-readable storage medium implement the functions specified in the boxes of the flowchart. The computer program instructions may also be loaded onto one or more computers or other programmable computing devices to cause a series of operational steps to be performed on the one or more computers or other programmable computing devices to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable processing device, provide steps for implementing the functions specified in the formulas, algorithms, and / or boxes of the flowchart.

[0112] Some or all of the methods and tasks described herein can be performed by a computer system and fully automated. In some cases, the computer system may include multiple different computers or computing devices (e.g., physical servers, workstations, storage arrays, etc.) that communicate and interoperate via a network to perform the described functions. Each such computing device typically includes a processor (or processors) that executes program instructions or modules stored in memory or other non-transitory computer-readable storage media or devices. The various functions disclosed herein may be embodied in such program instructions, but some or all of the disclosed functions may alternatively be implemented in the computer system's dedicated circuitry (e.g., ASIC or FPGA). In cases where the computer system includes multiple computing devices, these devices may, but do not necessarily, be located cooperatively. The results of the methods and tasks disclosed herein can be persistently stored by transforming physical storage devices (such as solid-state memory chips and / or disks) into different states.

[0113] Unless the context explicitly requires it, throughout the specification and claims, the words “comprising,” “including,” etc., should be interpreted in an inclusive sense, rather than an exclusive or exhaustive sense; that is, they have the meaning of “including but not limited to.” The term “coupled,” as generally used herein, refers to two or more elements that can be directly connected or connected via one or more intermediate elements. Furthermore, when used in this application, the terms “in this document,” “above,” “below,” and similar terms should refer to the entire application and not any particular part of it. Where the context permits, words used in the above specific embodiments to describe something in the singular or plural may also include the plural or singular, respectively. The word “or” refers to a list of two or more items, and this word encompasses all of the following interpretations: any item in the list, all items in the list, and any combination of items in the list. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any specific implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other specific implementations.

[0114] This disclosure is not intended to be limited to the specific embodiments shown herein. Various modifications to the specific embodiments described herein will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of this disclosure. The teachings of the invention provided herein can be applied to other methods and systems, not limited to those described above, and elements and actions of the various embodiments described above can be combined to provide other embodiments. Therefore, the novel methods and systems described herein can be embodied in many other forms; furthermore, various omissions, substitutions, and changes can be made to the form of the methods and systems described herein without departing from the spirit of this disclosure. The appended claims and their equivalents are intended to cover these forms or modifications that fall within the scope and spirit of this disclosure.

Claims

1. A receiver for a communication system, the receiver comprising: A first burst detector is configured to receive a digital signal transmitted through a channel and generate a first burst indicator by analyzing the physical structure of the received digital signal to determine whether a burst exists in the received digital signal. A signal decoder configured to: receive a first burst indicator; based on the first burst indicator, decode the received digital signal by processing the received digital signal to generate a decoded signal; and generate a decoding metric corresponding to successful decoding of the received digital signal. and A second burst detector is configured to generate a second burst indicator by analyzing the decoding metric and the information structure of the decoded signal corresponding to the received digital signal, to determine whether a burst exists in the received digital signal; wherein the information structure of the decoded signal includes one or more of the following: a total power estimate, a signal-to-noise ratio (SNR) estimate, and the Q of the decoded signal. 2 Value, I of the decoded signal 2 Decoder error parameters.

2. The receiver of claim 1, wherein the signal decoder is configured to decode the received digitized signal by iteratively processing the received digital signal to generate the decoded signal, the number of iterations being influenced by the first burst indicator generated by the first burst detector.

3. The receiver of claim 1, wherein the signal decoder and the first burst detector operate at least partially in parallel.

4. The receiver of claim 2, wherein if the first burst indicator indicates that there is no burst in the received digital signal, the number of iterations is limited to a minimum number of iterations, and if the first burst indicator indicates that there is a burst in the received digital signal, the number of iterations is limited to a maximum number of iterations, wherein the maximum number of iterations is greater than or equal to the minimum number of iterations.

5. The receiver of claim 4, wherein the burst in the received digital signal indicated by the first burst indicator is indeterminate, and the number of iterations is between the minimum number of iterations and the maximum number of iterations.

6. The receiver of claim 2, wherein the first burst detector estimates the probability of a burst in the received digital signal, and the number of iterations is affected by the estimated probability.

7. The receiver of claim 1, wherein the first burst detector uses data-assisted analysis based on known pilot symbols to analyze the physical structure of the received digital signal.

8. The receiver of claim 7, wherein the known pilot symbol comprises a buffer code of the received digital signal.

9. The receiver of claim 7, wherein the first burst detector uses the Neyman Pearson generalized likelihood ratio test (NP-GLRT) to analyze the physical structure of the received digital signal.

10. The receiver of claim 7, wherein the first burst detector uses a constant false alarm rate (CFAR) detector to analyze the physical structure of the received digital signal.

11. The receiver of claim 10, wherein the constant false alarm rate detector comprises a constant false alarm rate ratio summation (CFAR-SOR) detector.

12. The receiver of claim 10, wherein the constant false alarm rate detector comprises a constant false alarm rate summation ratio (CFAR-ROS) detector.

13. The receiver of claim 1, wherein the first burst detector uses a signal-to-noise ratio estimate to analyze the physical structure of the received digital signal.

14. The receiver of claim 1, wherein the first burst detector uses a total power estimate to analyze the physical structure of the received digital signal.

15. The receiver of claim 1, wherein the first burst detector analyzes the physical structure of the received digital signal by estimating the probability of a burst in the received digital signal.

16. The receiver of claim 15, wherein the first burst indicator corresponds to the estimated probability that a burst exists in the received digital signal.

17. The receiver of claim 16, wherein the behavior of the signal decoder is influenced by the estimated probability indicated by the first burst indicator.

18. The receiver of claim 16, wherein in response to the estimated probability being greater than a first value, the first burst indicator indicates the presence of a burst in the received digital signal, and in response to the estimated probability being less than the first value, the first burst indicator indicates the absence of a burst.

19. The receiver of claim 18, wherein the first value is based on the target false alarm probability.

20. The receiver of claim 16, wherein in response to the estimated probability being greater than a first value, the first burst indicator indicates the presence of a burst in the received digital signal; in response to the estimated probability being less than a second value, the first burst indicator indicates the absence of a burst; and in response to the estimated probability being between the first and second values, the first burst indicator indicates that the burst is indeterminate.

21. The receiver of claim 20, wherein the signal decoder is configured to decode the received digitized signal by iteratively processing the received digitized signal to generate the decoded signal, wherein the number of iterations is set to a minimum iteration value in response to a first burst indicator indicating the absence of a burst, the number of iterations is set to a maximum iteration value in response to a first burst indicator indicating the presence of a burst, and the number of iterations is set to an intermediate iteration value between the minimum iteration value and the maximum iteration value in response to a first burst indicator indicating that the burst is indeterminate.

22. The receiver of claim 1, wherein the second burst detector analyzes the information structure of the decoded signal by analyzing the total power estimate of the received digital signal to generate the second burst indicator.

23. The receiver of claim 1, wherein the second burst detector analyzes the information structure of the decoded signal by analyzing the signal-to-noise ratio (SNR) estimate of the received digital signal to generate the second burst indicator.

24. The receiver of claim 1, wherein the second burst detector analyzes the Q of the decoded signal. 2 value or I 2 The value is used to analyze the information structure of the decoded signal to generate the second burst indicator.

25. The receiver of claim 1, wherein the second burst detector analyzes the information structure of the decoded signal by analyzing decoder error parameters associated with the decoded signal to generate the second burst indicator.

26. The receiver of claim 1, wherein the second burst detector is further configured to generate a signal indicating that no further signal processing is performed on the decoded signal in response to determining that no burst exists in the received digital signal.

27. A method for determining the presence of a burst in a communication system, the method comprising: Receive digital signals transmitted through the channel; The first burst detector is used to generate a first burst indicator by analyzing the physical structure of the received digital signal in order to determine whether a burst exists in the received digital signal; Based on the first burst indicator, the received digital signal is decoded by processing the received digital signal to generate a decoded signal; A decoding metric is generated during the decoding of the received digitized signal, the decoding metric corresponding to the successful decoding of the received digitized signal; as well as A second burst detector is used to generate a second burst indicator by analyzing the decoding metric and the information structure of the decoded signal corresponding to the received digital signal, in order to determine whether a burst exists in the received digital signal; wherein, the information structure of the decoded signal includes one or more of the following: total power estimate, signal-to-noise ratio (SNR) estimate, Q of the decoded signal, etc. 2 Value, I of the decoded signal 2 Decoder error parameters.

28. The method of claim 27, wherein decoding the received digitized signal comprises iteratively processing the received digitized signal to generate the decoded signal, the number of iterations being influenced by the first burst indicator.

29. The method of claim 27, wherein decoding and generating the first burst indicator occur at least partially in parallel.

30. The method of claim 28, wherein if the first burst indicator indicates that there is no burst in the received digital signal, the number of iterations is limited to a minimum number of iterations, and if the first burst indicator indicates that there is a burst in the received digital signal, the number of iterations is limited to a maximum number of iterations, wherein the maximum number of iterations is greater than or equal to the minimum number of iterations.

31. The method of claim 30, wherein the burst in the received digital signal is indeterminate in response to the first burst indicator indicating that the number of iterations is between the minimum number of iterations and the maximum number of iterations.

32. The method of claim 28, further comprising estimating the probability of a burst in the received digital signal, wherein the number of iterations is affected by the estimated probability.

33. The method of claim 27, wherein the physical structure of the received digital signal is analyzed using data-assisted analysis based on known pilot symbols.

34. The method of claim 33, wherein the known pilot symbol comprises a buffer code of the received digital signal.

35. The method of claim 33, wherein the physical structure of the received digital signal is analyzed using the Neyman-Pearson generalized likelihood ratio test (NP-GLRT).

36. The method of claim 33, wherein a constant false alarm rate (CFAR) detector is used to analyze the physical structure of the received digital signal.

37. The method of claim 36, wherein the constant false alarm rate detector comprises a constant false alarm rate ratio summation (CFAR-SOR) detector.

38. The method of claim 36, wherein the constant false alarm rate detector comprises a constant false alarm rate summation ratio (CFAR-ROS) detector.

39. The method of claim 27, wherein a signal-to-noise ratio estimate is used to analyze the physical structure of the received digital signal.

40. The method of claim 27, wherein a total power estimate is used to analyze the physical structure of the received digital signal.

41. The method of claim 27, wherein the physical structure of the received digital signal is analyzed by estimating the probability of a burst in the received digital signal.

42. The method of claim 41, wherein the first burst indicator corresponds to the estimated probability that a burst exists in the received digital signal.

43. The method of claim 42, wherein decoding of the received digitized signal is influenced by the estimated probability indicated by the first burst indicator.

44. The method of claim 42, wherein in response to the estimated probability being greater than a first value, the first burst indicator indicates the presence of a burst in the received digital signal, and in response to the estimated probability being less than the first value, the first burst indicator indicates the absence of a burst.

45. The method of claim 44, wherein the first value is based on the target false alarm probability.

46. ​​The method of claim 42, wherein in response to the estimated probability being greater than a first value, the first burst indicator indicates the presence of a burst in the received digital signal; in response to the estimated probability being less than a second value, the first burst indicator indicates the absence of a burst; and in response to the estimated probability being between the first and second values, the first burst indicator indicates that the burst is indeterminate.

47. The method of claim 46, wherein decoding the received digitized signal comprises iteratively processing the received digitized signal to generate the decoded signal, wherein in response to a first burst indicator indicating the absence of a burst, the number of iterations is set to a minimum iteration value, in response to a first burst indicator indicating the presence of a burst, the number of iterations is set to a maximum iteration value, and in response to a first burst indicator indicating that the burst is indeterminate, the number of iterations is set to an intermediate iteration value between the minimum iteration value and the maximum iteration value.

48. The method of claim 27, wherein the information structure of the decoded signal is analyzed by analyzing the total power estimate of the received digital signal to generate the second burst indicator.

49. The method of claim 27, wherein the signal-to-noise ratio (SNR) estimate of the received digital signal is analyzed to analyze the information structure of the decoded signal to generate the second burst indicator.

50. The method of claim 27, wherein the Q of the decoded signal is analyzed. 2 value or I 2 The value is used to analyze the information structure of the decoded signal to generate the second burst indicator.

51. The method of claim 27, wherein the decoder error parameters associated with the decoded signal are analyzed to analyze the information structure of the decoded signal to generate the second burst indicator.

52. The method of claim 27, further comprising not performing further signal processing on the decoded signal in response to determining that there is no burst in the received digital signal.

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