Wireless communication with duplicate detection

Abstract

The aspects of this disclosure are intended for use with communications that may involve duplicate communication. As may be implemented according to one or more embodiments, a subset of symbols in the current data message (130 / 131) is used with a corresponding subset of symbols in a previous data message (120 / 121) to determine whether the current data message is a duplicate of the previous data message. This may involve, for example, generating a similarity measure to represent the similarity between the subset of data symbols in the current data message and the subset of data symbols in the previous data message (102). The similarity measure can be used to determine whether the current data message is a duplicate of the previous data message. This method can, for example, be used to determine whether the current message is a duplicate without having to decode the message.

Description

Technical Field

[0001] Aspects of various embodiments are directed to apparatus and methods for evaluating communications for duplication based on similarities between corresponding data symbols of data messages. Background Art

[0002] Wireless communications are used to transfer information between a transmitter and a receiver. For example, transmissions involving vehicle-to-everything (V2X) communications involve transmission and reception between a vehicle and another entity, and vice versa. Since vehicles (e.g., stations) employing V2X may utilize different communication standards, with vehicles using older standards and newer standards mixed operating in the same frequency band and / or channel, ensuring compatibility may be important. For example, a new standard message may reuse the same structure as an older standard message (e.g., a preamble followed by a data segment), even if sent at different transmission rates or repeated multiple times. Thus, some messages are new, while other messages may be repetitions of previous messages. Furthermore, while V2X communications have been useful, ensuring accurate and efficient transmissions may be challenging.

[0003] These and other issues have challenged the efficiency of wireless vehicle communication implementations for a variety of applications. Summary of the invention

[0004] Various example embodiments are directed to problems such as those set forth above and / or other problems that may become apparent from the following disclosure regarding repeated communications, and to determining whether a communication is a repeat of a previous communication. Various such methods involve making such determinations using a subset of received symbols relative to a subset of symbols in a previous communication. In certain example embodiments, aspects of the disclosure are directed to determining a similarity metric for a subset of symbols in a received communication, and determining whether a communication is a repeat based on the similarity metric. These methods can facilitate rapid identification of incoming packets and reduce the demand on resources such as buffer size and computing resources.

[0005] As may be implemented according to a more specific embodiment, the method proceeds as follows. A wireless data transmission is received via a communication circuit system and includes a subsequently communicated data message having a current data message and a previous data message that are received consecutively among the subsequently communicated data messages. Each of the subsequently communicated data messages is configured for asynchronous wireless reception according to a communication protocol and has a corresponding data message and a corresponding data symbol. For the current data message and the previous data message, a similarity metric is generated to represent a similarity between a subset of the data symbols of the current data message and a subset of the data symbols of the previous data message. In response, a determination is made whether the current data message is a repeat of the previous data message based on the similarity metric.

[0006] Another embodiment is directed to a device including a wireless communication receiver and a decoding circuit. The wireless communication receiver receives a communication including a wireless data message of a subsequent communication, the wireless data message of the subsequent communication having a current data message and a previous data message that are received continuously among the data messages of the subsequent communication. Each data message in the data messages of the subsequent communication is configured for asynchronous wireless reception according to a communication protocol and has a corresponding data message and a corresponding data symbol. The decoding circuit is configured to generate a similarity metric of the current data message and the previous data message, the similarity metric representing the similarity between a subset of the data symbols of the current data message and a subset of the data symbols of the previous data message. In response, the decoding circuit is further configured to determine whether the current data message is a repetition of the previous data message based on the similarity metric.

[0007] Aspects of the disclosure are defined in the following claims.

[0008] In a first aspect, a method is provided, the method comprising: receiving a wireless data transmission via a communication circuit system, the data messages of subsequent communication comprising a current data message and a previous data message received successively among the data messages of subsequent communication, each data message in the data messages of subsequent communication being configured for asynchronous wireless reception and having a corresponding data message and a corresponding data symbol according to a communication protocol; and for the current data message and the previous data message, generating a similarity metric to represent a similarity between a subset of the data symbols of the current data message and a subset of the data symbols of the previous data message; and in response, determining whether the current data message is a repetition of the previous data message based on the similarity metric.

[0009] In one or more embodiments, generating a similarity metric may include comparing a subset of data payload symbols in a current data message with a corresponding subset of data payload symbols in a previous data message; and determining that the current data message may be a repetition of the previous data message includes determining that the current data message is a repetition in response to the similarity metric indicating that a majority of symbols in the subset of symbols in the current data message match a subset of symbols in the previous data message.

[0010] In one or more embodiments, generating the similarity metric may include generating the similarity metric based on a subset of symbols in a previous data message and the current data message prior to decoding the subset of symbols in the current data message.

[0011] In one or more embodiments, before decoding a subset of symbols in a current data message, generating a similarity metric based on a subset of symbols in a previous data message and a current data message may include: starting a decoding process for a subset of symbols in the current data message; and generating a similarity metric using symbols at a stage in the decoding process before completing decoding of the subset of symbols and using symbols of the previous data message at a corresponding decoding stage.

[0012] In one or more embodiments, determining whether a current data message is a repetition of a previous data message may include: comparing a symbol in a header of the current data message with a corresponding symbol in the previous data message; and in response to the symbol in the header of the current data message failing to match the corresponding symbol in the previous data message, determining that the current data message is not a repetition of the previous data message.

[0013] In one or more embodiments, the steps of generating a similarity measure and determining whether the current data message is a repeat of a previous data message may be performed in response to a symbol in a header of the current data message matching a corresponding symbol in the previous data message.

[0014] In one or more embodiments, the subset of data symbols may include a subset of data symbols in a preamble, a payload, or a combination of a preamble and a payload of a current data message and a previous data message.

[0015] In one or more embodiments, the method may further include checking a cyclic redundancy check (CRC) status of a previous data message, wherein the steps of generating a similarity metric and determining whether the current data message is a repeat of the previous data message may be performed in response to the CRC status indicating that the previous data message was not correctly decoded.

[0016] In one or more embodiments, the method may further include: checking a cyclic redundancy check (CRC) status of a previous data message; in response to the CRC status of the previous data message indicating that the previous data message was not correctly decoded, comparing symbols in a header of the current data message with corresponding symbols in the previous data message, wherein the steps of generating a similarity measure and determining whether the current data message is a repetition of the previous data message are performed in response to the compared header symbols matching.

[0017] In one or more embodiments, the method may further include decoding the entire current message in response to one of: a CRC status indicating a correct decoding of a previous data message; and a mismatch of the compared header symbols.

[0018] In a second aspect, a device is provided, comprising: a wireless communication receiver for receiving a subsequently communicated wireless data message, the subsequently communicated wireless data message comprising a current data message and a previous data message received successively among the subsequently communicated data messages, wherein each data message in the subsequently communicated data message is configured for asynchronous wireless reception and has a corresponding data message and a corresponding data symbol according to a communication protocol; and a decoding circuit configured to generate a similarity metric for the current data message and the previous data message to represent a similarity between a subset of data symbols of the current data message and a subset of data symbols of the previous data message, and in response, determine whether the current data message is a repetition of the previous data message based on the similarity metric.

[0019] In one or more embodiments, the decoding circuitry may be configured to: generate a similarity metric by comparing a subset of data payload symbols in a current data message with a corresponding subset of data payload symbols in a previous data message; and determine that the current data message is a repetition of the previous data message in response to the similarity metric indicating that a majority of the symbols in the subset of symbols in the current data message match the subset of symbols in the previous data message.

[0020] In one or more embodiments, the decoding circuit may be configured to generate a similarity metric based on a subset of symbols in a previous data message and a current data message before decoding a subset of symbols in a current data message by starting a decoding process for a subset of symbols in the current data message, using symbols at a stage in the decoding process before completing decoding of the subset of symbols in the current message and generating a similarity metric using symbols of the previous data message at a corresponding stage in the decoding process.

[0021] In one or more embodiments, the decoding circuit may be configured to: compare symbols in a header of a current data message with corresponding symbols in a previous data message; and in response to symbols in the header of the current data message not matching corresponding symbols in the header of the previous data message, determine that the current data message is not a repetition of the previous data message and decode the current data message; and in response to symbols in the header of the current data message matching corresponding symbols in the previous data message, generate a similarity measure.

[0022] In one or more embodiments, the decoding circuit may be configured to: check a cyclic redundancy check (CRC) status of a previous data message; in response to the CRC status of the previous data message indicating that the previous data message was not correctly decoded, compare symbols in the header of the current data message with corresponding symbols in the previous data message; and in response to the compared header symbols matching, perform the functions of generating a similarity measure and determining whether the current data message is a repeat of the previous data message.

[0023] In a third aspect, a method is provided, the method comprising: receiving a current data packet and a previous data packet via a channel according to a communication protocol, on which wireless communication is transmitted for asynchronous reception; and generating a similarity metric based on a subset of symbols in the current data packet and a corresponding subset of symbols in the previous data packet, the similarity metric providing an indication of similarity between the subsets of symbols in the current data packet and the previous data packet; and determining whether the current data packet is a repetition of the previous data packet based on the similarity metric.

[0024] In one or more embodiments, the subset of symbols in the current data packet and the previous data packet may include one or both of data payload symbols and packet preamble symbols.

[0025] In one or more embodiments, generating the similarity measure may include using a subset of the symbols prior to decoding.

[0026] In one or more embodiments, the method may further include: checking a cyclic redundancy check (CRC) status of a previous data message; in response to the CRC status of the previous data message indicating that the previous data message was not correctly decoded, comparing symbols in a header of the current data message with corresponding symbols in the previous data message, wherein in response to the comparison indicating that the symbols in the headers of the current data message and the previous data message match, generating a similarity measure.

[0027] In one or more embodiments, the method may further include, in response to determining an indication that the current data packet is a repeat of a previous data packet, decoding the current data packet, and combining data from the current data packet and the previous data packet.

[0028] The above discussion / summary is not intended to describe each embodiment or every implementation of the present disclosure. The figures and subsequent detailed description also exemplify various embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various example embodiments may be more fully understood by considering the following detailed description in conjunction with the accompanying drawings, in which:

[0030] Figure 1 Example communication systems and methods according to the present disclosure are shown;

[0031] Figure 2 Example communications circuitry for multiple stations according to the present disclosure is shown;

[0032] Figure 3 Depicting a device with associated processing of received transmissions according to the present disclosure;

[0033] Figure 4 depicts a device with associated processing of received transmissions according to the present disclosure; and

[0034] Figure 5 Depicted is a data flow diagram for processing received transmissions in accordance with the present disclosure.

[0035] Although the various embodiments discussed herein are capable of modification and alternative forms, aspects of these embodiments have been illustrated by way of example in the drawings, and aspects of these embodiments will be described in detail. However, it should be understood that it is not intended to limit the present disclosure to the specific embodiments described. On the contrary, it is intended to cover all modifications, equivalents, and alternatives of the various aspects defined in the claims that fall within the scope of the present disclosure. In addition, the term "example" as used throughout this application is only by way of illustration and not limitation. DETAILED DESCRIPTION

[0036] Aspects of the present disclosure are considered to be applicable to a variety of different types of devices, systems and methods involving the confirmation of the presence of repeated communications (such as repetitions). Identifying communications as repeated can facilitate efficient processing while ensuring the processing of new communications. In certain embodiments, aspects of the present disclosure have been shown to be beneficial when used in the context of V2X communications and in the context of communication environments in which different communication protocols are used. For example, as protocols evolve, new protocols may need to operate in a manner that allows continued use of older (e.g., traditional) communications and related circuit systems, such as for situations in which new protocols can implement repetitions that older protocols fail to implement. Therefore, a new protocol station may retransmit a packet that is encoded in accordance with traditional standards. Traditional stations may be able to decode each repetition independently, while new protocol stations may perform advanced combinations of different repetitions to improve performance. Identifying such repetitions may be applicable to efficient processing as mentioned herein.

[0037] In some embodiments, a subset of symbols from a current communication being received is compared to a corresponding subset of symbols in a previously received communication, and this comparison is used to determine whether the current communication is a repeat of a previously received communication. In this way, a repeat communication can be detected without having to decode the entire communication. This can be useful for reducing processing time and energy, such as, for example, if a previous packet was correctly decoded (e.g., as indicated by a cyclic redundancy check (CRC)), then a repeat of the packet may not need to be decoded. Although not necessarily limited to this, various aspects may be understood through the following discussion using non-limiting examples of exemplary scenarios.

[0038] In the following description, various specific details are set forth to describe the specific examples presented herein. However, it should be apparent to those skilled in the art that one or more other examples and / or variations of these examples may be practiced without all the specific details given below. In other cases, well-known features are not described in detail to avoid confusing the description of the examples herein. For ease of illustration, the same reference numerals may be used in different figures to refer to the same elements or additional examples of the same elements. In addition, although various aspects and features may be described in individual figures in some cases, it should be understood that features from one figure or embodiment may be combined with features of another figure or embodiment, even if the combination is not explicitly shown or explicitly described as a combination.

[0039] Various embodiments are directed to identifying repetitions in packet-based communications by comparing incoming packets with previous packets based on symbols in each packet. For example, several orthogonal frequency division multiplexing (OFDM) symbols from each packet may be compared. Such symbols may be obtained at a point in the signal receiving circuitry process before decoding, such as at an equalizer output or at a log-likelihood ratio (LLR) processing level. Using these and other methods such as those characterized herein, a receiver may identify whether an incoming packet is a new packet or whether the packet belongs to a repeating sequence (such as may also be referred to as a retransmission sequence). In this case, a new packet may be received from a transmitter controlled by an acknowledgment channel, and a repeating packet may be received from the same transmitter. These methods are applicable to communications in which there may be no explicit marking of repetitions, such as where for all packets, the traditional short training field (L-STF) and traditional long training field (L-LTF) segments of the preamble are the same, the traditional signal field (SIG) symbol does not contain information about being part of a repetition, and the data symbol may also convey the same payload. In the case of successfully decoding more than one copy of the same retransmission sequence, the upper layer may filter out the message copy.

[0040] In some embodiments, the contents of the SIG symbols are first analyzed to quickly verify or discard packets that are not part of a retransmitted sequence. For example, while some SIG symbols may match, or nearly match (e.g., as indicated via a similarity metric), for different packets that are not part of a repeating sequence, detecting a mismatch in the SIG symbol may be used as an indication that the corresponding packet is not a repeat. Because the SIG symbol may be less susceptible to errors than data symbols and has its own error protection as a parity bit, in many cases the SIG symbol may be reliably used. Thus, if the SIG symbol does not identically match or exhibit a majority / threshold amount of matching data, then it may be determined that the corresponding packet is not part of a retransmitted sequence.

[0041] In further embodiments, the above method for comparing SIG symbols may be used as a first step, and those data packets having matching SIG symbols are additionally evaluated by evaluating one or more symbols in the data field to detect whether the data packet is a duplicate. For example, one or more first data symbols (or one or more LDPC blocks) may be evaluated and compared to detect duplication. In some cases, a similarity metric denoted as error vector magnitude (EVM) may be detected and compared for the respective packets. In other embodiments, the SIG symbol is used together with one or more symbols in the data payload to generate such a similarity metric. This metric generation may be performed at the equalization cluster level or LLR level as mentioned above, or at other locations in the receiver circuitry.

[0042] Various embodiments are directed to communications involving vehicles (such as, cars, trains, or ships), and other stations / devices may be implemented by drones, bicycles, pedestrians, and / or traffic controllers, may be in a dynamic communication environment (e.g., where some of the communication circuits are moving relative to each other), and include communication circuit systems for wirelessly communicating with other stations using a communication protocol, sometimes referred to herein as vehicle-to-everything (V2X) communications. In such cases, some exemplary implementations may utilize wireless communications according to various standards, such as the IEEE 802.11-OCB standard, which may be referred to as IEEE 802.11p, or as otherwise specified in the IEEE 802.11-2016 specification, or newer protocols such as IEEE 802.11bd (sometimes labeled Next Generation Vehicle (NGV)), which is fully incorporated herein by reference (e.g., for implementation Figure 1-2 Communication protocols and methods in ).

[0043] Various embodiments are directed to using standards such as IEEE 802.11bd, 3GPP 4G LTE-V2X, and / or 3GPP 5G NR standards. Standard features may improve overall system effectiveness while maintaining compatibility with older devices, such as "legacy IEEE802.11p" devices. As may be appreciated, a legacy device may include or refer to a device that provides V2X using an older standard, such as IEEE 802.11p, in the art. Thus, various aspects herein are directed to facilitating communications, such as repetitive communications, while maintaining compatibility for receiving communications using an older standard.

[0044] In a specific embodiment, the following method is performed to process incoming packets. If the previous packet has been correctly decoded (e.g., as indicated by a CRC pass), then the current packet can be systematically decoded without any combination. Although it is not necessary to decode the current packet when the current packet is part of a retransmission, it is not necessary to correctly decode the current packet because the previous packet was correctly decoded. Therefore, a decision process based on a similarity metric can be avoided (e.g., essentially forcing the comparison threshold to be exactly zero), and the decoded message can be checked to ensure that there are no repeats of error indications. In addition, if the current packet is a new / different packet, then the packet will need to be decoded anyway. If the previous packet has not been correctly decoded, then the current packet detected as a repeat based on the similarity metric can be combined with the previous packet. When a packet is evaluated as being repeatable (e.g., when the previous packet has not been correctly decoded as mentioned above), the content of the SIG symbol can be used as mentioned above to quickly verify or discard the packet as part of the retransmission sequence. Using the first data symbol (or set of symbols), packets with matching SIG symbols are additionally evaluated as being repeatable.

[0045] The data symbols may be compared in one or more of a variety of ways. In some embodiments, the similarity metric is implemented as an EVM metric characterizing the previous packet and the current packet determined using the equalizer output for a range of subcarriers i and symbols j as follows:

[0046]

[0047] EVM can provide a measure of the average delta between the equalizer output of the current packet and the equalizer output of the previous packet. Once the EVM measurement is calculated, it is compared to the pre-calculated EVM_threshold as follows:

[0048] If EVM < EVM_threshold, then the incoming packet is considered a duplicate; and

[0049] If EVM ≥ EVM_threshold, then the incoming packet is considered a new packet.

[0050] The EVM_threshold may be derived empirically or theoretically. When derived empirically, the EVM_threshold may be pre-calculated based on simulation results. For example, one may set the threshold based on MCS, target signal-to-noise ratio (SNR), packet length, and / or channel characteristics such as frequency offset, measured SNR, and channel estimates.

[0051] In some embodiments, similar measurements are made at the LLR level, for example at the output of a demod mapper.

[0052]

[0053] Referring to the formula for EVM using the above equalizer output, for a particular subcarrier, the term num can be expressed as follows under the square root:

[0054]

[0055] Where S (i,j) is the transmitted symbol, and N (i,j) For noise.

[0056]

[0057]

[0058] For a particular subcarrier, the term denom can be expressed as the denominator under the square root as follows:

[0059] And provide:

[0060]

[0061] The expected value E of EVM can be calculated as follows:

[0062]

[0063] If the previous group is the same as the current group, then the term num reduces to the noise component:

[0064]

[0065] When the noise approaches Inf, the numerator tends to zero, and the denominator tends to the average power of the cluster (e.g. 1 in the case of BPSK or QPSK). When the noise tends to -Inf, and assuming that the noise values ​​are independent, the term denom simplifies to only the noise component, and the expected value E can be:

[0066]

[0067] If the previous group is not the same as the current group, then you can use distribution.

[0068] The following additional characteristics of the above distribution relate to the modulation used to convey the signal. By way of example, we use QPSK modulation, which may be the most commonly used modulation for IEEE 802.11p messages, and it should be understood that similar methods may be performed for other modulations. QPSK has 4 possible modulation points, which may be labeled A, B, C, and D, and are represented as follows:

[0069]

[0070] When two randomly selected points are subtracted, the following result values ​​are acceptable (marked

[0071]

[0072] Condition <![CDATA[X 1 .X 2 Value of]]> <![CDATA[|X 1 .X 2 |value]]> AA i 1 AB -1 1 AC 1 1 AD -i 1

[0073] Assuming all cases are equally likely, and:

[0074]

[0075] When the noise tends to -Inf, provides the same results as for the previous section, since the term X is negligible. When the noise tends to +Inf, we have:

[0076]

[0077] In this case, for both -Inf and +Inf, E{EVM} approaches

[0078] For all cases, and as a generalization, and using the property in And suppose E{X 2}=E{Y 2}Since both noise and sign are independent, and assuming E{2XY}, we get:

[0079]

[0080] Therefore, for QPSK modulation, the following can be implemented:

[0081] In the absence of repetitions, the expected value of the EVM is always √2,

[0082] In the case of repetition, at low SNR, the expected value of EVM is √2, and at high SNR, the expected value is 0,

[0083] If the calculated EVM < √2, then it is more likely to be a duplicate, and

[0084] If the calculated EVM > √2, then it is more likely not to be a duplicate.

[0085] As the SNR increases, the confidence increases.

[0086] For a given number of symbols, the area where the first high percentile of the distribution of the same packet is lower than the first low percentile of the distribution of different packets is a safe zone, where repeated packets are easily distinguished from different packets. If the target SNR of such packets for each receiver is known (for example, for a packet of 1000 bytes, the transmission rate is 6 megabits / second, and the "identification SNR" is before 10% PER SNR, then the threshold (in EVM%) is set accordingly. For example, the SNR of a new packet (initial transmission) can be set to SNR_newpacket=10%PER SNR=0.6dB, and for repeated packets it can be set to SNR_repeat=10%PER SNR=-2.4dB.

[0087] The empirical threshold may be selected so that for any SNR>SNR_newpacket, there is less than 1% false detection of repeats, and for any SNR>SNR_repeat, there is less than 1% missed detection of repeats. Thus, the threshold may be selected to achieve the desired operation. Thus, if the EVM is below the threshold, then the incoming packet is determined to be part of a retransmitted sequence, and if the EVM is above the threshold, the incoming packet is determined to be a new packet.

[0088] In certain embodiments, packets are evaluated as follows. The CRC status of the previous packet is checked, and if the CRC status passes, the incoming message is decoded alone (without combining). If the CRC fails, the content of the SIG symbol is checked and compared to the SIG of the previous message. If the SIG symbol content is different, the incoming message is decoded alone (without combining). If the SIG symbol content is similar, a subset of the comparison symbols is used to determine whether the current packet is a duplicate packet as follows.

[0089] The symbols in the packet are decoded starting with a subset of OFDM symbols (e.g., five symbols) and compared with corresponding symbols in the previous packet to determine whether the packet is a duplicate. The subset of symbols may be data symbols in the data payload, symbols in the preamble, or a combination of data payload symbols and preamble symbols (e.g., one SIG symbol and four data symbols). This comparison may involve a similarity metric, and in particular may utilize an EVM metric (such as characterized above) as follows. If the EVM metric is below a threshold, then the incoming message is decoded in combination with the previous message. If the EVM metric is above a threshold, then the incoming message is decoded alone (without combination). To facilitate this aspect, the CRC and SIG states of the previous packet are stored, as well as the OFDM symbols to be used for the metric (e.g., equalized OFDM symbols), and the OFDM symbols of the incoming packet are buffered.

[0090] As can be implemented according to more specific embodiments, the method is performed as follows. Continuously receive wireless data transmissions including current data messages and previous data messages. The data message can be configured for asynchronous wireless reception and has a corresponding data message and a corresponding data symbol. Generate a similarity metric to represent the similarity between a subset of the data symbols of the current data message and a subset of the data symbols of the previous data message. The similarity metric is used to determine whether the current data message is a repetition of the previous data message. The subset of the data symbol may include, for example, a subset of the data symbols in the preamble, payload, or combination of the preamble and payload of the current data message and the previous data message. In certain embodiments, the cyclic redundancy check (CRC) state of the previous data message is checked, and the steps of generating a similarity metric and determining whether the current data message is a repetition of the previous data message are performed in response to a CRC state indicating that the previous data message is not correctly decoded.

[0091] The similarity metric may be generated and / or utilized in a variety of ways. In some embodiments, the similarity metric is generated by comparing a subset of data payload symbols in a current data message to a corresponding subset of data payload symbols in a previous data message. If the similarity metric indicates that a majority of the symbols in the subset of symbols in the current data message match a subset of symbols in the previous data message, then the current data message is determined to be a repeat of the previous data message.

[0092] In some embodiments, prior to decoding the subset of symbols in the current data message, a similarity metric is generated based on a subset of symbols in the previous data message and the current data message. For example, the similarity metric may be generated by initiating a decoding process for a subset of symbols in the current data message and using symbols at a stage in the decoding process prior to completing decoding of the subset of symbols and symbols of the previous data message at a corresponding decoding stage.

[0093] Determining whether a current data message is a repeat of a previous data message can be performed in a variety of ways. In some embodiments, a symbol in a header of the current data message is compared to a corresponding symbol in a previous data message. In response to a symbol in the header of the current data message failing to match a corresponding symbol in the previous data message, it is determined that the current data message is not a repeat of the previous data message. In this embodiment, determining a similarity measure and determining whether the current data message is a repeat of a previous data message can be performed in response to a symbol in the header of the current data message matching a corresponding symbol in the previous data message.

[0094] In a particular embodiment, a cyclic redundancy check (CRC) status of a previous data message is checked, and in response to a CRC status of a previous data message indicating that the previous data message was not correctly decoded, a symbol in a header of the current data message is compared with a corresponding symbol in the previous data message. If the compared header symbols match (or are, for example, nearly similar), then the steps of generating a similarity metric and determining whether the current data message is a previous data message are repeated. In some cases, the entire current message is decoded in response to one of the following: a CRC status indicating that the previous data message is correctly decoded and / or the compared header symbols do not match.

[0095] Another embodiment is directed to an apparatus including a wireless communication receiver and a decoding circuit that processes messages via detecting repetitions. The wireless communication receiver sequentially receives a current data message and a previous data message. The decoding circuit generates a similarity metric for the current data message and the previous data message, the similarity metric representing a similarity between a subset of data symbols of the current data message and a subset of data symbols of the previous data message. The decoding circuit determines whether the current data message is a repetition of the previous data message based on the similarity metric.

[0096] The decoding circuitry is implemented in a variety of ways to suit a particular embodiment. In some embodiments, the decoding circuitry generates a similarity metric by comparing a subset of data payload symbols in a current data message to a corresponding subset of data payload symbols in a previous data message, and determines whether the current data message is a repeat of the previous data message in response to the similarity metric indicating that a majority of the subset of symbols in the current data message matches the subset of symbols in the previous data message.

[0097] In other embodiments, the decoding circuit generates a similarity metric based on a subset of symbols in a previous data message and the current data message before decoding the subset of symbols in the current data message. A decoding process for the subset of symbols in the current data message is initiated and the similarity metric is generated using symbols at a stage of the decoding process before decoding of the subset of symbols in the current message is completed and using symbols of the previous data message at a corresponding stage in the decoding process.

[0098] In some embodiments, the decoding circuit is configured to compare a symbol in a header of a current data message with a corresponding symbol in a previous data message. If the symbol in the header of the current data message does not match the corresponding symbol in the header of the previous data message, then determine that the current data message is not a repeat of the previous data message, and decode the current data message. If the symbol in the header of the current data message matches the corresponding symbol in the previous data message, then generate a similarity measure.

[0099] In other embodiments, the decoding circuit checks a cyclic redundancy check (CRC) status of a previous data message and compares symbols in a header of the current data message with corresponding symbols in the previous data message when the CRC status of the previous data message indicates that the previous data message was not correctly decoded. If the compared header symbols match (or, for example, if the headers closely or nearly match), then a similarity metric is generated and used to determine whether the current data message is a repeat of the previous data message.

[0100] Turning now to the accompanying drawings, Figure 1 An example wireless communication system and method involving data message communication is shown, some of which are repeated. A plurality of vehicles 102-106 and other vehicles / devices 107-N are shown, some or all of which may participate in the communication, and one or more of which include a communication circuit system that uses repeated communication to communicate according to one or more embodiments as characterized herein. In the case of various embodiments, the vehicle and / or other vehicle / device may include an automobile, a train, a ship, a bicycle, and / or a pedestrian device (e.g., a mobile phone or a wearable device), or a non-mobile device such as may be implemented by a roadside unit or a traffic controller (e.g., a traffic light, a gate, a bridge, and a railroad crossing). Each such vehicle / device may include a station that implements the communication as characterized herein.

[0101] In a particular embodiment, vehicle 102 communicates with vehicles operating using different protocols, including vehicle 104 operating with a (first) traditional communication protocol and vehicle 105 operating with a (second) NGV communication protocol. Vehicle 102 may also operate in a denser environment involving vehicle 103 and / or 106 and one or more of other vehicles / devices 108-N. The receiver circuit system in vehicle 102 wirelessly collects information from transmissions associated with a traditional communication protocol (at least from vehicle 104) and from transmissions associated with another communication protocol (at least from vehicle 105), respectively, which may be through a specific wireless communication channel. Other transmissions according to the traditional communication protocol may be received from vehicle 103 or one or more of other vehicles / devices 107-N. Additional transmissions according to other (e.g., NGV or 3GPP 5G NR) communication protocols may be received from vehicle 106 or one or more of other vehicles / devices 107-N, some or all of which may also be communicated via traditional communication protocols.

[0102] The receiver circuitry in the vehicle 102 evaluates the received communication in a manner consistent with one or more embodiments herein to determine whether the communication is a duplicate. A subset of the data symbols in the current data message and the previous data message may be compared, and the comparison may be used to determine the likelihood that the current data message is a duplicate. For example, with reference to a new transmission from a conventional device at the vehicle 104 (or, as may also be received from an NGV device at the vehicle 105) having a preamble 130 and a payload 131, the symbols in the payload 131 may be compared to the symbols in the payload 121 of the previous message having the preamble 120. When the messages are different, in response to the receiver circuitry in the vehicle 102 decoding the entire payload 131, the comparison of the symbols indicates so.

[0103] With reference to the repeated transmission of the preamble 110A and payload 111A corresponding to the preamble 110 and payload 111 of the previous message from the NGV device at the vehicle 105 (or as can be received from other devices in other ways), the symbol in the payload 111A can be compared with the symbol in the payload 111 to detect whether the current message is a repetition from the previous message. For example, a similarity metric can be calculated with the symbols from the payload 111A and the payload 111, which should meet the threshold level of similarity to indicate that the current message is a repetition. In other embodiments, the symbol in the preamble 110A can be compared with the symbol in the preamble 110, or the preamble symbol can be used in a similar manner to calculate the similarity metric. Other embodiments relate to the use of symbols in the preamble and payload sections of the message for comparison and / or metric generation. Therefore, when, for example, the payload 111 may not be fully correctly decoded, the message can be combined to facilitate accurate decoding.

[0104] In certain embodiments, the receiver circuitry in the NGV device 102 processes the incoming data message as follows. The CRC status of the previous message is checked, and if the CRC status is qualified, the current message is decoded without combining. In this case, if the current message is a new message, a full decode will be required, and if the current message is a repeat, decoding the repeat will confirm the repeated nature and the message can be discarded. If the CRC fails, the content of the SIG symbol in the current packet is checked and compared with the SIG symbol of the previous message. If the SIG symbol content is different, the current message is decoded alone without combining, so that the difference can indicate that the current message is new. If the SIG symbol content is similar, then a subset of the comparison symbols is used to determine whether the current message is a repeat message as follows.

[0105] Initiate decoding of a subset of the data payload symbols in the current message, compare or otherwise use the subset of the data payload symbols with corresponding symbols in a previous packet at a stage in the decoding process (e.g., at an equalizer output). This comparison may involve a similarity metric, and in particular, may utilize an EVM metric as characterized above.

[0106] exist Figure 1 The wireless communications depicted in the description may involve V2X communications, which may include multiple types of communications, such as: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). In specific cases, the V2X network may enable information to be exchanged between multiple vehicles, and in some cases other devices. As can be appreciated, as used herein, "circuitry" refers to one or more circuits, such as multiple similarly operating (or versions of) circuits operating in a respective vehicle, one or more of which may involve programmable devices utilizing software. Vehicles may communicate messages to each other via vehicle communication circuits, such as speed measurements, communication measurements, GPS data, etc.

[0107] The communication protocol technologies characterized herein, including traditional and other / NGV technologies, may be IEEE 802.11 based technologies, such as IEEE 802.11p or other Wi-Fi technologies. Figure 1 , each of the newer standard and older standard devices / vehicles may thus be implemented with a communication circuit system that wirelessly communicates using a communication protocol consistent with Wi-Fi or IEEE 802.11p based communications. The communication protocol used may involve sending messages asynchronously. For example, the communication circuit system may observe (e.g., listen to) a channel and communicate in response to the channel being clear (e.g., not transmitting a message).

[0108] Figure 2Example communication circuits of respective stations according to various embodiments are shown. Each of the communication circuits 210, 212, and 214 may communicate wirelessly in a wireless communication network using a communication protocol. Figure 2 A first communication circuit 210 and a second communication circuit 212 operating according to a first (eg, newer / other) communication type (eg, standard) and a third communication circuit system 214 operating according to a second (eg, older / legacy) communication type are shown. Figure 1 , circuit 210 may be implemented by vehicle 102 , circuit 212 may be implemented by vehicle 105 , and circuit 214 may be implemented by vehicle 104 .

[0109] The communication circuits 210, 212, 214 include certain general circuitry types that may be similarly implemented. The first communication circuit 210 includes a transmit (TX) processor 216 and a receive (RX) processor 222 used with a controller / processor 220 to implement various functions for transmitting and receiving messages according to legacy and newer / other communication protocols. The first communication circuit system 210 also includes a transmitter 219, a receiver 221, and an antenna 218.

[0110] Communication circuits 212 and 214 also include similar components using corresponding notations (e.g., 218' and 218" also designate antennas). For communication circuits 210 and 212, controller / processor 220 and controller / processor 226 also include similarity metric generators 213 and 228 that generate similarity metrics as characterized by one or more embodiments herein. Communication circuit 214 is shown as having a controller / processor 230 that is operable to transmit and receive (and decode) signals according to a second protocol. In this way, first communication circuit 210 and second communication circuit 212 are reverse compatible for receiving communications from third communication circuit system 214 (and, as well, for sending certain communications to the third communication circuit system 214).

[0111] Each of the first communication circuit system 210, the second communication circuit system 212, and the third communication circuit system 214 may communicate wirelessly using a communication protocol in which messages are sent asynchronously and on the same channel. The messages may each have a preamble that includes a legacy short training field (L-STF) (e.g., may be 8 microseconds) that provides support for synchronization and automatic gain control (AGC) calibration, a legacy long training field (L-LTF) (e.g., may be 16 microseconds) that provides a channel estimation pilot for decoding subsequent Wi-Fi-based symbols, and a signal field (SIG) symbol that conveys an MCS (e.g., may be 8 microseconds).

[0112] Thus, the communication circuit may evaluate messages received via the antenna 218, receiver 221, and receive processor 222 of the communication circuit, implementing the controller processor 220 and similarity metric generator 213 of the communication circuit to generate similarity metrics based on a subset of symbols in the messages received from circuits 212 and 214 (etc.). For example, when circuits 212 or 214 confirm control of the channel and send a new message, the new message may be detected by comparing the data in the preamble SIG field. For new messages with the same SIG field, the symbols in the corresponding payload may be compared before decoding the entire message to determine whether the message is a duplicate, and processed accordingly.

[0113] As can be appreciated, communications (and, if applicable, communications networks) are not limited to those provided by Figure 1 and 2 The number of stations and / or communication circuitry shown. Various embodiments may include more or fewer stations with communication circuitry in a shared device geographic location, as well as additional or fewer types of stations with communication circuitry (e.g., mobile phones). The number of stations may also change over time due to movement of vehicles or other stations and / or additional stations entering a shared station geographic location (e.g., forming one or more ad-hoc networks).

[0114] Figure 3 Depicted is a device 300 with correlated processing of subsequently received transmissions in accordance with the present disclosure. Figure 3 The upper portion shows receiving the first or initial transmission, and Figure 3 The lower portion of shows receiving repetition. The device 300 operates as a receiver having various blocks that perform corresponding functions as indicated. In this case, block 342 is collected based on L-STF samples from antenna IA samples received at 340. Block 344 utilizes L-LTF samples and feeds to channel estimation block 346. Block 348 utilizes SIG samples and feeds to SIG decoding block 350, which is also fed by channel estimation block 346. Block 352 utilizes data samples and feeds to fast Fourier transform (FFT) subcarrier extraction block 354. Equalizer 356 is fed by subcarrier extraction block 354 and receives information such as can be used for equalization from channel estimation block 346. The remaining blocks include de-interleaving (DIL) 358, log likelihood ratio (LLR) generation 360, LLR combination 362, Viterbi decoding 364 and finally the output of the decoded bits at 366. Accumulator block 368 may save LLRs from previous transmissions to provide to LLR block 362. One or more of the blocks shown may be omitted, or other blocks may be implemented in a different receiver / decoder, as may be implemented with various embodiments.

[0115] By way of example, a similarity measure can be used as in Figure 3The symbols shown in the first emission in the upper part and in Figure 3 The symbols in the second transmission in the lower portion of are generated by the repetition detection block 305. Specifically, a first option may involve comparing a subset of the symbols output from the equalizer 356, the output at the LLR soft decision sequence generation in the second transmission (and, e.g., the same as stored in the accumulator 368 from the initial transmission), or the output in the hard decision sequence bits leaving the Viterbi decoder 366.

[0116] In some embodiments, the similarity metric is generated based on statistics or signatures from the Viterbi decode block 364, such as a path metric distribution after a defined period of time, which can be compared (correlated) for the first (previous) and second (new) transmissions.

[0117] Figure 4 Depicted is a device 400 having associated processing involving re-encoded received transmissions in accordance with the present disclosure. Figure 4 The block shown in Figure 3 Those blocks in are labeled and can be implemented in the usual way, where Figure 4 The initial (or previous) communication is depicted in the upper portion of Figure 4 The second (current) communication is depicted in the lower portion of . As such, additional discussion of those similarly labeled blocks is omitted for simplicity. The device 400 also includes a re-encoding block 410 that re-encodes a subset of the decoded bits at 366 from the initial transmission. The re-encoding may include, for example, convolution-coding, modulation mapping, interleaving, and inverse fast Fourier transform (IFFT) operations. The repeat detection block 305 uses the re-encoded subset from the first transmission, and the corresponding subset of the symbols in the second transmission, to determine whether the second transmission is a repeat. In this case, data about the previous transmission may be retained for determining whether the second transmission is a repeat in a compact manner.

[0118] Figure 5 A data flow diagram for processing a received transmission according to the present disclosure is depicted, the transmission comprising a current packet and a previous packet. At block 500, an incoming (current) packet is acquired and the SIG field of the incoming (current) packet is decoded at block 502. The CRC status of the previous packet is checked at block 510, and if it is determined at 512 that the CRC has passed, then full symbol decoding is initiated at block 520 without combining the current packet with the previous packet. If the CRC has not passed, then at 514 the SIG field of the current packet is compared to the SIG field (516) of the previous packet. If the SIG fields are not identical (or do not sufficiently match), then at block 520 full symbol decoding is initiated without combining the current packet with the previous packet.

[0119] If the SIG fields are identical, or sufficiently matched, then at 514, a process is initiated for determining whether the current packet is a duplicate. At block 530, full symbol decoding is initiated for a subset of the symbols in the current packet (e.g., without combining with corresponding symbols in a previous packet), and a similarity metric called EVM is generated using corresponding symbols 534 from the previous packet (e.g., at the output of an equalizer). At 532, if the EVM is less than a threshold, indicating that the current packet is not a duplicate, then full symbol decoding is initiated at block 520 without combining the current packet with the previous packet. At 532, if the EVM is not less than a threshold, then full symbol decoding is initiated at block 540 using a combination with corresponding symbols in a previous packet.

[0120] Aspects of the present disclosure are directed to use with communications that may involve repeated communications. As may be implemented according to one or more embodiments, a subset of symbols in a current data message is used with a corresponding subset of symbols in a previous data message to confirm whether the current data message is a repeat of the previous data message. This may involve, for example, generating a similarity metric to represent the similarity between a subset of data symbols of the current data message and a subset of data symbols of the previous data message. The similarity metric may be used to determine whether the current data message is a repeat of the previous data message. This method may be used, for example, to confirm whether the current message is a repeat without having to decode the message.

[0121] Unless otherwise indicated, those skilled in the art will recognize that the various terms used in the specification (including claims) mean the ordinary meanings in the art. As an example, the specification describes and / or illustrates various aspects useful for implementing the claimed disclosure through various circuits or circuit systems, which can be shown as or using circuit types such as blocks, modules, devices, systems, units, controllers, receivers, decoding circuits, CRC checks, and / or other circuit types (e.g., Figure 2 The reference numerals 210, 220, 222, and 216 depict the terminology of blocks / modules described herein. Such circuits or circuit systems are used with other elements to illustrate how certain embodiments can be performed in form or structure, steps, functions, operations, activities, etc. For example, in some of the embodiments discussed above, one or more modules are configured and arranged to be used as can be Figure 3-5 In some embodiments, such programmable circuits are one or more computer circuits that include memory circuitry for storing and accessing a program to be executed as a set (or multiple sets) of instructions (and / or used as configuration data to define how the programmable circuit executes) and are used by the programmable circuits as described by Figure 5The algorithm or process described herein is to perform the relevant steps, functions, operations, activities, etc. Depending on the application, the instructions (and / or configuration data) may be configured for implementation in a logic circuit system, where the instructions (whether characterized by the form of object code, firmware or software) are stored in a memory (circuit) and can be accessed from the memory. As another example, where this specification may refer to "a first [structural type]", "a second [structural type]", etc., where [structural type] may be replaced with terms such as ["circuit", "circuitry", etc.], the adjectives "first" and "second" are not used to imply any structural description or provide any substantive meaning; rather, such adjectives are used only as English antecedents to distinguish one similarly named structure from another similarly named structure (e.g., "a first circuit configured to convert..." is interpreted as "a circuit configured to convert...").

[0122] Based on the above discussion and description, it will be readily appreciated by those skilled in the art that various modifications and changes may be made to the various embodiments without strictly following the exemplary embodiments and applications shown and described herein. For example, the method as illustrated in the accompanying drawings may involve steps performed in various orders, wherein one or more aspects of the embodiments herein are retained, or may involve fewer or more steps. For example, different numbers of symbols may be decodable for generating a similarity metric or for use in comparisons in addition. As another example, symbols may be compared at different stages in a decoding or receiving process. Such modifications do not depart from the true spirit and scope of the various aspects of the present disclosure, including the various aspects set forth in the claims.

Claims

1. A method, characterized in that include: receiving, via the communication circuitry, a wireless data transmission, a subsequently communicated data message comprising a current data message and a previous data message received successively among the subsequently communicated data messages, each of the subsequently communicated data messages being configured for asynchronous wireless reception according to a communication protocol and having a corresponding data message and a corresponding data symbol; and Check the cyclic redundancy check (CRC) status of the previous data message; responsive to a CRC status of a previous data message indicating that the previous data message was not correctly decoded, comparing symbols in a header of a current data message with corresponding symbols in the previous data message; generating, for the current data message and the previous data message, a similarity metric representing a similarity between a subset of the data symbols of the current data message and a subset of the data symbols of the previous data message in response to the compared symbols in the header of the current data message matching the compared corresponding symbols in the previous data message; and In response, a determination is made whether the current data message is a duplicate of the previous data message based on the similarity measure.

2. The method according to claim 1, characterized in that Generating the similarity measure includes comparing a subset of data payload symbols in the current data message to a corresponding subset of data payload symbols in the previous data message; and Determining that the current data message is a repetition of the previous data message includes determining that the current data message is a repetition in response to the similarity metric indicating that a majority of symbols in the subset of symbols in the current data message match the subset of symbols in the previous data message.

3. A method according to any of the preceding claims, characterised in that Generating the similarity metric includes generating the similarity metric based on a subset of symbols in the previous data message and a current data message prior to decoding the subset of symbols in the current data message.

4. The method according to claim 3, characterized in that Prior to decoding the subset of symbols in the current data message, generating the similarity metric based on the subset of symbols in the previous data message and the current data message comprises: initiating a decoding process for said subset of symbols in said current data message; and The similarity metric is generated using the symbols at a stage in the decoding process prior to completing decoding of the subset of symbols and using the symbols of the previous data message at a corresponding decoding stage.

5. A method according to any of the preceding claims, characterised in that Determining whether the current data message is a repetition of the previous data message includes: comparing symbols in a header of the current data message with corresponding symbols in the previous data message; and In response to the symbol in the header of the current data message failing to match the corresponding symbol in the previous data message, it is determined that the current data message is not a repeat of the previous data message.

6. A device, characterized in that: include: a wireless communication receiver for receiving subsequently communicated wireless data messages, the subsequently communicated wireless data messages comprising a current data message and a previous data message received successively among the subsequently communicated data messages, each of the subsequently communicated data messages being configured for asynchronous wireless reception according to a communication protocol and having a corresponding data message and a corresponding data symbol; and A decoding circuit, the decoding circuit being configured to: Check the cyclic redundancy check (CRC) status of the previous data message; responsive to a CRC status of a previous data message indicating that the previous data message was not correctly decoded, comparing symbols in a header of a current data message with corresponding symbols in the previous data message; generating a similarity metric to represent a similarity between the subset of data symbols of the current data message and the subset of data symbols of the previous data message in response to the compared symbols in the header of the current data message matching the compared corresponding symbols in the previous data message; and In response, a determination is made whether the current data message is a duplicate of the previous data message based on the similarity measure.

7. The device according to claim 6, characterized in that The decoding circuit is configured to: generating the similarity measure by comparing a subset of data payload symbols in the current data message to a corresponding subset of data payload symbols in the previous data message; and In response to the similarity metric indicating that a majority of the symbols in the subset of symbols in the current data message match the subset of symbols in the previous data message, determining that the current data message is a repeat of the previous data message.

8. The device according to claim 6 or 7, characterized in that The decoding circuit is configured to generate the similarity metric based on a subset of symbols in the previous data message and the current data message before decoding the subset of symbols in the current data message by: initiating a decoding process for a subset of said symbols in said current data message, The similarity metric is generated using the symbols at a stage in the decoding process prior to completing decoding of the subset of symbols in the current data message and using the symbols of the previous data message at a corresponding stage in the decoding process.

9. The device according to claim 6 or 7, characterized in that The decoding circuit is configured to: comparing symbols in a header of the current data message with corresponding symbols in the previous data message; and responsive to the symbol in the header of the current data message not matching the corresponding symbol in the header in the previous data message, determining that the current data message is not a repeat of the previous data message, and decoding the current data message; The similarity metric is generated in response to the symbol in the header of the current data message matching the corresponding symbol in the previous data message.

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