Communication that uses the current preamble to decode the previous message

Abstract

Aspects of the present disclosure relate to wireless communications involving consecutively received messages. As may be implemented according to one or more aspects characterized herein, a preamble segment (122) of a currently received message (120) is used to decode a previously received message (110) for wireless transmission from a wireless transmitter (102) over a wireless communication channel (101). The current message and the previous message are received consecutively with a time gap (130) between the current message and the previous message.

Description

Technical Field

[0001] Aspects of the various embodiments relate to apparatus and methods for evaluating communications. Background Art

[0002] Wireless communication is 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, as well as transmission and reception between an entity and a vehicle. Because vehicles (e.g., stations) employing V2X may utilize different communication standards, with a mix of vehicles using older and newer standards operating in the same frequency band and / or channel, ensuring compatibility may be important. For example, new standard messages may utilize repetition as continuous retransmissions of a particular message to improve quality. Data from repeated messages may be combined to improve performance. However, while V2X communications are very useful, ensuring accurate and efficient transmissions can 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, which may be apparent from the following disclosure regarding the use of a preamble of a current message while processing a previously received message, relate to the problems set forth above and / or other problems. In certain example embodiments, aspects of the present disclosure relate to using a currently received repeated preamble to perform channel estimation and decoding of a previously received repeated version. It has been recognized / discovered that using a preamble segment of a subsequently received message can enhance decoding of a previous message, for example, by improving channel estimation and / or replacing a preamble that may have been interfered with or may not be desired. Thus, such approaches can address challenges such as those characterized above.

[0005] Aspects of the present disclosure relate to a method as follows. A wireless transmission is received from a wireless transmitter over a wireless communication channel, and the wireless transmission includes a current message and a previous message received consecutively, with a time gap between the current message and the previous message. Each message has a preamble segment and a payload data segment, the preamble including information for characterizing the wireless communication channel. For example, the preamble segment may include a short training field (STF), a long training field (LTF), and a signal field (SIG), wherein the LTF provides information for characterizing the wireless communication channel (e.g., providing a channel estimate). The previous message is decoded based on the preamble segment in the previous message and based on the preamble segment in the current message. In certain specific example embodiments, based on the preamble segment in the previous message being corrupted or undesirable, information from the preamble segment of the current message is used for decoding.

[0006] In one or more embodiments, the payload data may include a set of bits that are received in time sequence in an orthogonal frequency division multiplexing (OFDM) symbol and start with a first bit and end with a last bit; and decoding the previous message may include: using the preamble segment of the previous message to decode a subset of bits starting with the first bit and continuing in sequence with subsequently received bits, and using the preamble segment of the current message to decode a subset of bits starting with the last bit and continuing in reverse sequence with previously received bits.

[0007] In one or more embodiments, decoding the previous message may include using the preamble segment of the previous message to determine a channel estimate of the communication channel, and using the preamble segment of the current message to improve the determined channel estimate.

[0008] In one or more embodiments, decoding the previous message may include, in response to the current message being a repetition of the previous message, decoding the previous message using the preamble segment of the current message.

[0009] In one or more embodiments, decoding the previous message may include decoding bits in the payload data segment starting with a last received bit and continuing with previously received bits in reverse order.

[0010] In one or more embodiments, the method may further include: evaluating whether the time gap is less than a threshold time gap; and decoding the previous message may be performed in response to the time gap being less than the threshold.

[0011] In one or more embodiments, decoding the previous message may include: in response to the preamble segment in the previous message being corrupted, using the preamble segment in the current message to decode the payload data segment in the previous message.

[0012] In one or more embodiments, the method may further include providing feedback by re-encoding decoded bits from the previous message to generate a re-encoded modulation signal and comparing the re-encoded modulation symbols to received equalized symbols of the previous message.

[0013] In one or more embodiments, decoding the previous message based on the preamble segment in the previous message and based on the preamble segment in the current message may include: using the preamble segment in the current message to generate a channel estimate for the channel on which the message is received.

[0014] Another embodiment relates to an apparatus comprising communication circuitry and decoding circuitry. The communication circuitry is configured to receive a wireless transmission from a wireless transmitter over a wireless communication channel, the wireless transmission comprising a current message and a previous message received consecutively with a time gap between the current message and the previous message. Each message has a preamble segment and a payload data segment, wherein the preamble includes information for characterizing the wireless communication channel. The decoding circuitry is configured to decode the previous message based on the preamble segment in the previous message and based on the preamble segment in the current message.

[0015] In one or more embodiments, the payload data may include a set of bits that are received in time sequence in an orthogonal frequency division multiplexing (OFDM) symbol and start with a first bit and end with a last bit, and the decoding circuit system may be configured to decode the previous message by using the preamble segment of the previous message to decode a subset of bits starting with the first bit and continuing in sequence with subsequently received bits, and using the preamble segment of the current message to decode a subset of bits starting with the last bit and continuing in reverse sequence with previously received bits.

[0016] In one or more embodiments, the decoding circuit system can be configured to decode the previous message by using the preamble segment of the previous message to determine a channel estimate of the communication channel, and using the preamble segment of the current message to improve the determined channel estimate.

[0017] In one or more embodiments, the decoding circuitry may be configured to decode the previous message using the preamble segment of the current message in response to the current message being a repetition of the previous message.

[0018] In one or more embodiments, the decoding circuitry may be configured to decode bits in the payload data segment starting with a last received bit and continuing with previously received bits in reverse order.

[0019] In one or more embodiments, the decoding circuitry may be configured to evaluate whether the time gap is less than a threshold time gap, and decode the previous message in response to the time gap being less than the threshold.

[0020] In one or more embodiments, the decoding circuit system can be configured to decode the payload data segment of the previous message using the preamble segment in the current message in response to the preamble segment in the previous message being corrupted, thereby decoding the previous message.

[0021] In one or more embodiments, the decoding circuit system can be configured to: re-encode the decoded bits of the payload data segment in the previous message; and evaluate errors in the decoding of the bits in the previous message by comparing the re-encoded bits with the received bits in the payload data segment of the previous message.

[0022] In one or more embodiments, the decoding circuitry may be configured to adjust the decoding of the previous message in response to the evaluation indicating an error in the decoding of the bits in the payload data segment of the previous message.

[0023] In one or more embodiments, the decoding circuitry may be configured to decode the previous message by using the preamble segment in the current message to generate a channel estimate for the channel over which the message was received.

[0024] The above discussion / summary is not intended to describe each embodiment or every implementation of the present disclosure. The following figures and detailed description also illustrate various embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various example embodiments may be more fully understood upon consideration of the following detailed description in conjunction with the accompanying drawings, in which:

[0026] Figure 1 is a system level diagram illustrating an example communication environment and method according to the present disclosure;

[0027] Figure 2 shows circuitry and related communication processing according to the present disclosure; and

[0028] Figure 3 Also shown are circuitry and related communication processes in accordance with the present disclosure.

[0029] Although the various embodiments discussed herein are susceptible to modification and alternative forms, aspects of the various embodiments have been illustrated by way of example in the drawings and 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 falling within the scope of the present disclosure, including those defined in the claims. In addition, the term "example," as used throughout this application, is intended to be illustrative only and not limiting. DETAILED DESCRIPTION

[0030] Aspects of the present disclosure are believed to be applicable to a variety of different types of devices, systems, and methods involving wireless communications that utilize corresponding communication messages to characterize / facilitate the reception of other communication messages. In certain embodiments, aspects of the present disclosure have proven beneficial when used in vehicle-to-everything (V2X) communications and other communications that may involve the transmission of repeatable, continuous messages from a particular source. For example, various aspects relate to applications in IEEE 802.11bd (NGV) technology to improve performance and mitigate interference that may arise due to partial packet collisions. In some embodiments, the preamble segment of a continuous / repeated message is used to decode or otherwise process a previously received message. Essentially, the repeated preamble can serve as a postamble for the previous message and can improve channel estimation quality and decoding (e.g., the continuously received preamble can be utilized to decode the previous packet on a symbol-by-symbol basis, starting from the end of the packet). The various aspects may be understood through the following discussion using non-limiting examples in an exemplary context, but are not necessarily limited thereto.

[0031] Therefore, 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. Similarly, although aspects and features may be described in various figures in some cases, it should be understood that features from one figure or embodiment may be combined with features from another figure or embodiment, even if the combination is not explicitly shown or explicitly described as a combination.

[0032] Aspects of the present disclosure are believed to be applicable to a variety of different types of devices, systems, and methods involving utilizing a preamble segment in a message to decode or otherwise process aspects of a previously received message, such as in applications utilizing repetitive communications (repeated communications) in which the same message is repeated to facilitate accurate reception. In certain embodiments, aspects of the present disclosure have proven to be beneficial when used in the context of V2X communications and in communications environments where messages are sensitive to communication errors.

[0033] In some embodiments, a conventional long training field (L-LTF) segment of a postamble is used to improve channel estimation and / or decode a previous message, whereby a preamble segment of a repeated message, such as received in the gap between previous messages, is used as the postamble of the previous message. Thus, the L-LTF can be used to improve channel estimation and / or decode a previously received message based on symbols, and this can be done starting from the end of the L-LTF. In some embodiments, this method facilitates decoding of such previous messages where the preamble segment of the previous message is noisy or otherwise impaired (e.g., due to overlapping signals), which may, for example, affect the quality of the channel estimate.

[0034] In various cases, the preamble of the current message can be used alone or in combination with the preamble of the previous message to improve the channel estimation accuracy of the previous message or provide robustness in the presence of partial interference. When decoding the previous message, the enhanced channel estimate can be used to obtain better performance and / or can in turn facilitate the decoding of the previous message. In certain receiver embodiments, such as those in which decoding of data segments is performed based on OFDM symbols to allow for a feedback loop for channel tracking purposes, the preambles in the previous message and the current message are used to decode the previous convolutionally encoded message from both ends of the received data packet. For example, Viterbi decoding can be performed in a sequential manner starting from the front of the data segment of the previous message and moving forward, and starting from the back of the data segment and moving backward. By increasing the probability of correctly decoding the previous message, the probability of correctly decoding a repeated sequence can be increased. In addition, the probability of not needing the current (repeated) message when the previous message is successfully decoded can be increased, and this can reduce power consumption.

[0035] In various embodiments, the time gap between the completion of reception of the previous message and the start of reception of the preamble segment of the current message is utilized to be shorter than the coherence time of the channel. This approach can help ensure that the preamble segment in the current message is useful for channel estimation / decoding of the previous message. The coherence time can be a function of the carrier frequency and the Doppler frequency, and is typically calculated as: coherence_time_usec = 0.423 / freq_doppler_Hz * 1e6, for example, a coherence time of 108 microseconds for a carrier frequency of 5.9 GHz and a Doppler frequency of 3.9 kHz (corresponding to a speed of 500 km / h with a 5.9 GHz + 0.2 kHz mismatch between the transmitter and receiver clocks). For example, the gap between repetitions according to the IEEE 802.11 type standard can be less than the short interframe space (SIFS) of 32 microseconds and can help ensure that the previous message and the current message were sent from the same transmitter. For example, assuming a 32 microsecond gap between repetitions, the time gap from the LTF of the current message to the last OFDM symbol of the previous message can be 8 / 2 (half the last OFDM symbol of the previous packet) + 32 (SIFS) + 16 (L-STF) + 16 / 2 (half the L-LTF) = 60 microseconds, which can be less than the previously mentioned coherence time of 108 microseconds. Coherence can also be used to ensure that the preamble segment of the current message is valid relative to the previous message, ensuring that the acceptable coherence time is greater than any reception gap. In addition, as the gap time increases, the preamble segment of the current message may still be valid for symbols received later in the previous message.

[0036] Thus, various embodiments can utilize the preamble segment of the current message in conjunction with processing of the previous message. Such an approach, as can be used in conjunction with an existing DATA symbol decoder, can facilitate improved channel estimation quality. In some embodiments, information from the LTF sequences in both the current message and the previous message is utilized, for example, via interpolation, weighted summing, or averaging. This can improve channel estimation accuracy (and packet error rate (PER) performance), for example, in receivers without a feedback loop.

[0037] Certain embodiments involve decoding DATA symbols (using a per-symbol decoder) using the preamble of the current message, starting from the end of a received packet for a previously received message. For example, for messages communicated according to the IEEE 802.11p standard having a sequence of continuous OFDM data symbols without any additional LTF segments in between, such as in automotive applications and / or for handling rapidly changing channels, a per-symbol decoding scheme can be used for OFDM data symbols with a feedback loop. As OFDM symbols are scanned, the feedback loop is used to (e.g., continuously) update the channel estimate. Using the preamble of the current message, the previous message can be decoded starting from the end of the packet. An initial channel estimate can be derived from the LTFs in the current message, and the channel estimate can also be updated as the symbols are scanned in descending order.

[0038] In some embodiments, DATA symbols are decoded in both the forward and backward directions. For example, the preamble of the previous message can be used to begin decoding the symbols with the first received symbol, and the preamble of the current message can be used to begin decoding the symbols with the last received symbol of the previous message, and so on. In addition, each corresponding preamble segment of the previous message and the current message can be used to decode the data symbols separately, and the decoding can be compared or otherwise combined for accuracy.

[0039] In one such embodiment, the data symbols include a cyclic redundancy check (CRC) checksum. The same data packet can be decoded both forward and backward, and the best of both decodings can be used. For example, the preamble of the previous message can be used to first perform forward decoding. If the CRC of this decoding fails, the preamble of the current message can be used to decode the data symbols starting from the end. This technique can provide improvements (e.g., within a range of 0.3 dB).

[0040] In another such embodiment, the decoded payloads are combined at the bit level. For example, if the CRC for both the forward and backward decoding fails, the output of the forward decoder can be used for the earlier data symbols (e.g., the first half of the payload), and the output of the backward decoder can be used for the later data symbols (e.g., the second half of the payload).

[0041] In yet another embodiment, the decoded symbols are systematically combined at the decoded bit level. Each decoder runs only to the "middle" or some other predetermined portion of the payload, with the output of the decoder going forward (and using the preamble of the previous message) being used for the first portion of the payload and the output of the decoder going backward (and using the preamble of the current message) being used for the second portion of the payload.

[0042] Aspects of the present disclosure relate to a method and / or associated apparatus for receiving (e.g., via receiver circuitry) and processing (e.g., via decoding circuitry) a wireless transmission from a wireless transmitter over a wireless communication channel. The wireless transmission comprises a current message and a previous message received consecutively, with a time gap between the current message and the previous message. Each message has a preamble segment and a payload data segment, the preamble including information used to characterize the wireless communication channel. The previous message is decoded based on the preamble segment in the previous message and based on the preamble segment in the current message. In such cases, decoding can be performed in response to the current message being a repetition of a previous message, where such messages were sent from the same transmitter. In addition, such a method can enhance communication, for example, in the event that a preamble segment in a previous message is corrupted (and in response, the preamble of the current message is used to replace the preamble of the previous message).

[0043] Various embodiments relate to applications in which the payload data comprises a set of bits received in time order, for example, in an Orthogonal Frequency Division Multiplexing (OFDM) symbol, starting with the first bit and ending with the last bit. In some embodiments, the bits in the payload data segment are decoded using the preamble of the current message, starting with the last received bit and continuing in reverse order with the previously received bits. In certain embodiments, the preamble segments of each of the current and previous messages are used. For example, the preamble segment of the previous message can be used to decode a subset of bits starting with the first bit and continuing in sequence with the subsequently received bits. The preamble segment of the current message can similarly be used to decode a subset of bits starting with the last bit and continuing in reverse order with the previously received bits. In some embodiments, the preamble segment of the previous message is used to decode the first portion of the bits, and the preamble segment of the current message is used to decode the second portion of the bits (e.g., without overlap), and the decoded results can be combined. In other embodiments, each decoding is used to decode all bits, and the decoded results are also used together.

[0044] In the previously described cases and / or in other cases herein, decoding can refer to performing a channel estimate and subsequently using the channel estimate in decoding the data in the payload segment. For example, the preamble segment of a previous message can be used to determine a channel estimate for the communication channel, and the preamble segment of the current message can be used to improve the determined channel estimate. This improved channel estimate can then be further used in the decoding process. In other cases, the preamble segment of the current message is used to provide a channel estimate for the previous message, which can be useful, for example, when the preamble of the previous message is noisy due to interference.

[0045] In some embodiments, the time gap between corresponding messages is evaluated as an indication of whether the preamble segment of the current message can be used to decode the previous message. For example, if the gap is less than a threshold time gap, the previous message can be evaluated as a repeat, and the preamble segment of the current message can be used for decoding.

[0046] In certain embodiments, a feedback loop is implemented by re-encoding the decoded bits, for example by re-encoding the bits during the Viterbi decoding process until they become modulation symbols, and comparing such re-encoded modulation symbols with received equalized symbols. Feedback can thus be provided to characterize the decoding operation.

[0047] As mentioned above, various embodiments relate to an apparatus for data reception and decoding (e.g., for decoding a previous message). Thus, certain embodiments relate to an apparatus having communication circuitry and decoding circuitry, wherein the communication circuitry receives a wireless transmission as characterized above, and the decoding circuitry decodes the previous message based on a preamble segment in the previous message and based on a preamble segment in the current message.

[0048] Now turning to the diagram, Figure 1 A system-level diagram illustrating an example communication environment and method according to the present disclosure is shown. By way of example, communication circuitry is shown within a plurality of vehicles 102-106 and other vehicles or devices 107-N, which may be implemented with traffic controllers, pedestrians, or other components. Certain embodiments relate to a single such device, such as device 102, while other embodiments relate to a system involving multiple such devices. Additionally, such communications may be performed by a mix of enhanced (e.g., NGV) devices that utilize duplication and may utilize the decoding methods characterized herein, as well as conventional types of devices that may not utilize duplication and / or the required decoding methods.

[0049] By way of example, reference is made to device 102, in which receiver circuitry can wirelessly gather information from transmissions associated with one or more other vehicles / devices, respectively. Successively received communications 110 and 120, separated by a time gap 130, can be processed within the device using a channel estimation block 140, a signal (SIG) decoding block 141, and a data decoding block 142. By way of example, each of these communications is shown having a preamble segment having a short training field (STF) 111 / 121, a long training field (LTF) 112 / 122, and a signal (SIG) field 113 / 123. Each communication also includes a payload segment comprising data 114 / 124, which can be implemented, for example, using OFDM symbols.

[0050] The channel estimation block 140 utilizes the LTF 122 (depicted as a legacy LTF (L-LTF)) of the current communication 120 to provide channel estimation and decoding of the previous message 110 as characterized herein, e.g., for decoding the SIG field 113 and the data segment 114. In some embodiments, the channel estimation block 140 also generates a channel estimate based on the LTF 112, e.g., by using two LTF segments and / or by determining that the preamble of the previous message 110 was corrupted and therefore avoiding the use of the LTF 112.

[0051] In some embodiments, LTF 112 is used to decode the bits in data segment 114 starting from the last received bit and working backwards toward the first received bit. This method can further utilize LTF 112 to decode the bits in data segment 114 starting from the first received bit and working forwards toward the last received bit. Thus, each LTF can be used to decode all bits separately and the decoded results can be used together, or can be used to decode a corresponding subset of bits that can then be combined.

[0052] Thus, the vehicle 102 may communicate with one or more other vehicles / devices using this method in which repeated preamble segments may be used to decode previous messages. Figure 1 The wireless communications depicted may relate to V2X communications, which may include various types of communications, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). In specific instances, a V2X network enables the exchange of information between multiple vehicles, and in some instances, other devices. As may be appreciated, as used herein, "circuitry" refers to one or more circuits, such as multiple similarly operating circuits (or versions of circuits) operating in a corresponding vehicle, one or more of which may involve programmable devices utilizing software. Vehicles may transmit messages to each other via vehicle communication circuitry, such as speed measurements, communication measurements, GPS data, and the like.

[0053] The communication protocol technology characterized herein, including traditional and other / NGV technologies, may be based on IEEE 802.11 technology, such as IEEE 802.11p or other Wi-Fi technologies. Figure 1 Each of the newer standard and older standard devices / vehicles can therefore be implemented with communication circuitry that wirelessly communicates using a communication protocol consistent with Wi-Fi or IEEE 802.11p-based communications. The communication protocol used can involve sending messages asynchronously. For example, the communication circuitry can observe (e.g., listen) a channel and communicate in response to the channel being clear (e.g., no messages being transmitted).

[0054] Figure 2 2 shows a circuit system 200 for transmitting wireless signals and related communication processing according to the present disclosure. By way of example, communications 210 and 220 are shown with a time gap 230 and similar to Figure 1Communications 110 and 120 in FIG. 1 have a preamble segment with STFs 211 / 221, LTFs 212 / 222, and SIGs 213 / 223. Each communication also includes a payload segment that includes data 214 / 224. Channel estimation blocks 215 and 225 perform channel estimation based on the LTFs 212 / 222, and SIG decoding blocks 216 and 226 decode the SIG field from each communication using their respective channel estimation block outputs, which are then combined at block 240. The channel estimates may also be combined at block 250 and used with the combined SIG at block 260 for decoding the data segment 214. The decoded payload may then be output at block 270. This may be done, for example, with Figure 1 The illustrated vehicle 102 and / or other vehicles / devices may be used to implement the circuit system 200. Additionally, antenna, transmitter, and receiver circuit systems may also be used in conjunction with the circuit blocks.

[0055] In some embodiments, the channel estimates obtained from the adjacent L-LTF symbols 212 / 222 are used to decode the SIG symbols 213 / 223, respectively (e.g., as Figure 1 To decode the data segment 214 of the previous packet, information from either the SIG symbol decoding or the combined decoding may be used.

[0056] Figure 3 FIG. 3 shows a circuit system 300 for transmitting wireless signals and related communication processing according to the present disclosure. By way of example, according to Figure 2 Messages 210 and 220 are again shown and labeled as corresponding messages in FIG. In this example, channel estimation is performed at block 325 using LTF 222, and the output of the channel estimation is used to decode the SIG segment at block 326. These decoded segments are then used to decode the data segment 214 of message 210 at block 340, and a decoded payload 350 is output from block 340.

[0057] As may be appreciated, communications (and, as may be applicable, communications networks) are not limited to Figure 1 、 2 and 3. 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 movement of additional stations into a shared station geographic location (e.g., to form an ad hoc network).

[0058] Terms that illustrate orientations, such as upper / lower, left / right, top / bottom, and above / below, may be used herein to refer to the relative positions of elements as shown in the drawings. It should be understood that these terms are used for convenience only, and that in actual use, the disclosed structures may be oriented differently from the orientations shown in the drawings. Therefore, these terms should not be interpreted in a limiting manner.

[0059] Unless otherwise indicated, those skilled in the art will recognize that the various terms used in the specification (including the claims) are meant to have ordinary meaning in the art. For example, the specification describes and / or illustrates various aspects of the claimed disclosure that may be implemented with the aid of various circuits or circuit systems, which may be shown as terms such as blocks, modules, devices, systems, units, controllers, transmitters, receivers, transceivers, and / or other circuit type depictions (e.g., reference numerals 140, 141, and 142 may depict blocks / modules as described herein), or using such terms. Such circuits or circuit systems are used with other elements to illustrate how certain embodiments may be implemented in form or structure, steps, functions, operations, activities, etc. For example, in certain of the embodiments discussed above, one or more modules are discrete logic circuits or programmable logic circuits that are configured and arranged to implement these operations / activities, such as may be described herein. Figure 1 and 2 In some embodiments, such programmable circuitry is one or more computer circuits including memory circuitry for storing and accessing a program to be executed as a set of instructions (and / or a program to be used as configuration data to define how the programmable circuitry is to execute), and an algorithm or process as described in conjunction with the channel estimation / decoding method or as described in conjunction with the figures, which is used by the programmable circuitry to perform the relevant steps, functions, operations, activities, etc. Depending on the application, the instructions (and / or configuration data) can be configured to be implemented in logic circuitry, where the instructions (whether characterized as object code, firmware, or software) are stored in and accessible from the memory (circuitry). 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 a term 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 merely English antecedents to distinguish one such similarly named structure from another similarly named structure (e.g., “a first circuit configured to convert...” is interpreted as “a circuit configured to convert...”).

[0060] Aspects of the present disclosure relate to wireless communications involving consecutively received messages. As may be implemented according to one or more aspects featured herein, a preamble segment of a currently received message is used to decode a previously received message for wireless transmission from a wireless transmitter over a wireless communication channel. The current message and the previous message are received consecutively, with a time gap between the current message and the previous message.

[0061] Based on the above discussion and illustration, it will be readily apparent to those skilled in the art that various modifications and changes may be made to the various embodiments without strictly adhering to the exemplary embodiments and applications shown and described herein. For example, the method illustrated in the figures 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, a message received in addition may be utilized to evaluate a previously received message in a similar manner. Additionally, messages received simultaneously, overlappingly, or continuously on different channels may be utilized in a similar manner. Such modifications do not depart from the true spirit and scope of the various aspects of the present disclosure, including those set forth in the claims.

Claims

1. A method, characterized in that include: Receiving a wireless transmission from a wireless transmitter on a wireless communication channel (101, 102), the wireless transmission comprising a current message (120) and a previous message (110) received consecutively, the current message (120) and the previous message (110) being separated by a first time gap (130), each message having a preamble segment and a payload data segment, the preamble segment comprising a short training field, a long training field and a signal field, the preamble comprising information for characterizing the wireless communication channel; wherein the first time gap is adjacent to the data segment of the previous message and the short training field of the current message, and In response to a second time gap between a long training field of the current message and a payload data segment of the previous message being less than a coherence time of the channel, and in response to the current message being a repeat of the previous message, decoding orthogonal frequency division multiplexing (OFDM) symbol bits of the previous message based on the long training field and the signal field of the preamble segment in the current message instead of the preamble segment of the previous message (102); wherein each payload data segment comprises a set of bits mapped to bits of an OFDM symbol, the set of bits being received in time order, starting with a first received bit in a first OFDM symbol and ending with a last received bit in a last OFDM symbol; Decoding the previous message includes: The bits of the convolutionally encoded payload data segment are Viterbi decoded, starting with the last received bit and continuing with previously received bits in reverse order based on the preamble segment in the current message to determine a decoded set of bits.

2. The method according to claim 1, characterized in that Decoding the previous message includes using the preamble segment of the previous message to decode a subset of bits starting with a first bit and continuing with subsequently received bits in the order received.

3. A method according to any of the preceding claims, characterised in that Decoding the previous message includes: When the current message is received, an initial channel estimate of the communication channel is determined using the long training field of the preamble segment of the current message to represent the channel, a subset of bits in the payload data segment of the previous message is decoded based on the channel estimate and corresponding to the last OFDM symbol of the previous message, and the remaining bits are decoded in reverse order toward the first received bit in the payload data segment of the previous message using the updated channel estimate.

4. The method according to claim 1 or 2, characterized in that: Additionally including calculating a coherence time of the channel based on a long training field of a current message and evaluating whether the second time gap is less than the coherence time of the channel; and The decoding of the previous message is performed in response to the second time interval being less than the coherence time of the channel.

5. The method according to claim 1 or 2, characterized in that: Decoding the previous message includes, in response to the preamble segment in the previous message being corrupted, decoding the payload data segment in the previous message using the preamble segment in the current message.

6. The method according to claim 1 or 2, characterized in that: Also includes: Feedback is provided by re-encoding the decoded bits from the previous message to generate a re-encoded modulation signal and comparing the re-encoded modulation symbols to the received equalized symbols of the previous message.

7. The method according to claim 1 or 2, characterized in that: Decoding the previous message based on the preamble segment in the previous message and based on the preamble segment in the current message includes using the preamble segment in the current message to generate a channel estimate for the channel over which the message was received.

8. A device, characterized in that include: A communication circuit system (200) configured to receive a wireless transmission from a wireless transmitter on a wireless communication channel, the wireless transmission comprising a current message (220) and a previous message (210) received consecutively, the current message (220) and the previous message (210) having a first time gap (230) between them, each message having a preamble segment (211-213; 221-223) and a payload data segment (214 / 224), the preamble segment may include a short training field, a long training field and a signal field, the preamble including information for characterizing the wireless communication channel, wherein the first time gap is adjacent to the data segment of the previous message and the short training field of the current message; and Decoding circuitry (260) configured to, in response to a second time gap between a long training field of the current message and a payload data segment of the previous message being less than a coherence time of the channel and in response to the current message being a repeat of the previous message, decode (102) orthogonal frequency division multiplexing (OFDM) symbol bits of the previous message based on the long training field and the signal field of the preamble segment in the current message instead of the preamble segment of the previous message; wherein each payload data segment comprises a set of bits mapped to bits of an OFDM symbol, the set of bits being received in time order, starting with a first received bit in a first OFDM symbol and ending with a last received bit in a last OFDM symbol; Decoding the previous message includes: Viterbi decoding bits of the convolutionally encoded payload data segment, starting with the last received bit and continuing with previously received bits in reverse order based on the preamble segment in the current message, thereby determining a decoded set of bits; using the preamble segment of the previous message to decode a subset of bits starting with a first bit and continuing in sequence with subsequently received bits, and The preamble segment of the current message is used to decode a subset of bits starting with a last bit and continuing with previously received bits in reverse order.

9. The device according to claim 8, characterized in that The payload data comprises a set of bits received in time order in an Orthogonal Frequency Division Multiplexing (OFDM) symbol, starting with a first bit and ending with a last bit, and the decoding circuitry is configured to decode the previous message by: The preamble segment of the previous message is used to decode a subset of bits starting with the first bit and continuing in sequence with subsequently received bits.

10. The device according to claim 8 or 9, characterized in that The decoding circuitry is configured to decode the previous message by: When the current message is received, an initial channel estimate of the communication channel is determined using the long training field of the preamble segment of the current message to represent the channel, a subset of bits in the payload data segment of the previous message is decoded based on the channel estimate and corresponding to the last OFDM symbol of the previous message, and the remaining bits are decoded in reverse order toward the first received bit in the payload data segment of the previous message using the updated channel estimate.

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