TWI680650B - Transmitters, receivers and methods of transmitting and receiving - Google Patents

Abstract

A receiver recovers data from orthogonal frequency division multiplexing (OFDM) symbols, the OFDM symbols including a plurality of subcarrier signals. Some of the subcarrier signals carry data symbols and some of the subcarrier signals carry pilot symbols. The pilot symbols include scattered pilot symbols and continuous pilot symbols. According to the continuous pilot symbol pattern, the continuous pilot symbols are distributed across the subcarrier signals, and according to the scattered pilot signal pattern, the scattered pilot symbols are distributed across the subcarrier signals. The receiver includes a demodulator configured to detect signals representing the OFDM symbols, and to generate a digital version of the time domain samples of the OFDM symbols. The Fourier transform processor is configured to receive the time-domain digital version of the OFDM symbols and the frequency of the OFDM symbols from where the pilot symbol carrying the subcarrier and the data symbol carrying the subcarrier can be restored. Domain version. The detector is configured to recover the data symbols from the data of the subcarriers carrying the OFDM symbols, and from the pilot of the subcarriers carrying the OFDM symbols according to the scattered symbol pattern and the continuous pilot symbol pattern, Restore the pilots symbol. The scattered pilot symbol pattern is one of a plurality of scattered pilot symbol patterns, and the continuous pilot pattern is independent of the scattered pilot symbol pattern. The detector includes a memory configured to store a main continuous pilot pattern, and a detector configured to detect the number of subcarrier signals in the plurality of subcarrier signals and derive the continuous pilot from the main pilot pattern based on the number of subcarrier signals. Frequency pattern processor.

Description

Transmitter, receiver and method for transmitting and receiving

The disclosure of the present invention relates to a transmitter, a receiver, and a method for transmitting and receiving in an OFDM communication system.

There are many examples of radio communication systems in which the data is communicated using orthogonal frequency division multiplexing (OFDM). It has been configured to operate a system that conforms to the Digital Video Broadcasting (DVB) standard, such as using OFDM. OFDM can be generally described as providing K narrowband subcarriers (where K is an integer), which are modulated in parallel. Each subcarrier communicates with a modulation data symbol, such as a quadrature amplitude modulation (QAM) symbol or a quadrature shift. Phase Keying (QPSK) symbol. The modulation of these subcarriers is formed in the frequency domain and transformed to the time domain for transmission. Because the data symbols are communicated in parallel on the subcarriers, the same modulation symbol can be communicated on each subcarrier for an extended period, which can be longer than the coherence time of the radio channel. The subcarriers are modulated in parallel at the same time, so that the modulated carrier combination forms an OFDM symbol. The OFDM symbol thus includes a plurality of subcarriers, each of which has been modulated simultaneously with a different modulation symbol.

To facilitate detection and data recovery on the receiver, the OFDM symbol may include a pilot subcarrier that communicates data symbols known to the receiver. The pilot subcarriers provide a phase and time reference, which can be used to estimate the impulse response of the channel through the passed OFDM symbols, and perform tasks such as channel estimation and correction, frequency offset estimation, and the like. These estimates facilitate detection and data recovery at the receiver. In some examples, the OFDM symbols include two Continuous Pilot (CP) carriers, which are maintained at the same relative frequency position in the OFDM symbols and Scattered Pilots (SP). The SPs change their relative position in the OFDM symbol between consecutive symbols, providing a more accurate estimate of the impulse response of the channel that facilitates reducing redundancy. However, the positions of the pilots need to be known to the receiver so that the receiver can extract the pilot symbols from the correct positions distributed on all of the OFDM subcarriers.

The development of communication systems using OFDM symbols for data communication can represent a significant and complex task. In particular, the optimization of communication parameters, particularly related to frequency planning and network deployment, can present a significant effort requiring considerable effort to identify technical issues with these communication parameters applicable to communication systems utilizing OFDM. It is understandable that a lot of work has been performed to optimize the parameters of the DVB standard, and especially DVB T2.

A receiver recovers data from orthogonal frequency division multiplexing (OFDM) symbols, the OFDM symbols including a plurality of subcarrier signals. Some of the subcarrier signals carry data symbols and some of the subcarrier signals carry guidance The pilot symbols include scattered pilot symbols and continuous pilot symbols. The continuous pilot symbols are distributed on all of the subcarrier signals to conform to the continuous pilot symbol pattern and the scattered pilot symbols are distributed on all of the subcarrier signals to conform to the scattered pilot. Signal pattern. The receiver includes a demodulator configured to detect signals representing the OFDM symbols, and to generate digital versions of the OFDM symbols in the time domain samples. Fourier transform processor configured to receive the time-domain digital version of the OFDM symbols and the frequency at which the OFDM symbols are formed from where the pilot symbol carrying the subcarrier and the data symbol carrying the subcarrier can be restored Domain version. The detector is configured to restore the data symbols from the data of the subcarrier signals carrying the OFDM symbols based on the scattered symbol pattern and the continuous pilot symbol pattern, and from the pilot of the subcarrier signals carrying the OFDM symbols. And restore the pilot symbols. The scattered guide symbol pattern is one of a plurality of scattered guide symbol patterns, and the continuous guide pattern is independent of the scattered guide symbol pattern. The detector includes a memory configured to store a main continuous pilot pattern, and a detector configured to detect the number of subcarrier signals in the plurality of subcarrier signals and derive the continuous guide from the main pilot pattern based on the number of subcarrier signals. Lead pattern processor.

The provision of a continuous pilot pattern independent of the scattered pilot pattern means that when there are a plurality of scattered pilot patterns, fewer continuous pilot patterns must be stored in the memory. In addition, the ability to derive a continuous pilot pattern from the main pilot pattern dependent on the number of subcarriers may allow fewer continuous pilot patterns to be stored in memory when the number of subcarriers varies from symbol to symbol.

In some examples, the sub-carriers in the plurality of sub-carrier signals The number of wave signals is one of the number of subcarrier signals in a group, and the main pilot symbol pattern is the pilot symbol pattern of the continuous pilot symbols for OFDM symbols, and the OFDM symbols include the signals from the group of subcarriers. The highest number of subcarrier signals for the number of carrier signals.

The provision of a primary pilot pattern is for the highest order subcarrier pattern, which means that the pilot subcarrier for a pattern with fewer subcarriers can be derived without the need to store separate pilot patterns. This therefore allows a single pilot pattern to be stored to cover all possible subcarrier numbers, thus saving memory where any continuous pilot pattern needs to be stored for each pattern.

In some examples, the set of subcarriers includes approximately 8k, 16k, and 32k subcarriers, the main pilot pattern will be provided to the 32k subcarriers, and the continuous pilots for the 8k and 16k subcarriers The pattern is derived from the 32k subcarrier continuous pilot pattern.

Various further aspects and features of the present technology are defined in the scope of the attached application and include a transmitter for transmitting OFDM symbols, a method for transmitting OFDM symbols, and a method for receiving OFDM symbols.

1‧‧‧source coding and multiplexing

2‧‧‧ Video Encoder

4‧‧‧ audio encoder

6‧‧‧ Data Encoder

10‧‧‧Program Multiplexer

12‧‧‧ Connect channel

20‧‧‧OFDM transmitter

22‧‧‧ Multiplexer adaptation and energy dispersion block

24‧‧‧ Forward Error Correction Encoder

26‧‧‧bit interleaver

28‧‧‧ Cluster Mapper

30‧‧‧Time-Interleaver

31‧‧‧ Other channels

32‧‧‧Frame Builder

33‧‧‧Symbol interleaver

36‧‧‧ Pilot and embedded signal formation

37‧‧‧OFDM symbol builder block

38‧‧‧OFDM Modulator

40‧‧‧Protection Insertion Processor

42‧‧‧ Digital to Analog Converter

44‧‧‧RF Front End

46‧‧‧ Antenna

64‧‧‧OFDM symbols

66‧‧‧OFDM symbols

68‧‧‧Frame Closed Symbol (FCS)

100‧‧‧ Antenna

102‧‧‧ Tuner

104‧‧‧ Analog to Digital Converter

106‧‧‧ Guard Interval Removal Processor

108‧‧‧ Fast Fourier Transformer (FFT) Processor

110‧‧‧ channel estimator and corrector

111‧‧‧ Embedded signal decoding unit

112‧‧‧Decoder

114‧‧‧Symbol Deinterleaver

116‧‧‧bit deinterleaver

118‧‧‧Error correction decoding

120‧‧‧continuous pilot symbols

122‧‧‧Scattered pilot

124‧‧‧ blind spot

126‧‧‧ Band

Embodiments of the present invention will be described below by way of example, with reference only to the accompanying drawings, wherein similar components are provided with corresponding reference numerals: FIG. 1 provides a schematic diagram of an example OFDM transmitter; FIG. 2 provides a Example OFDM superframe; Figure 3 provides a schematic diagram of an example OFDM receiver; Figure 4 provides a schematic diagram of a portion of an example OFDM frame; and Figure 5 provides a description of the distribution of continuous pilot positions in a DVB T2 system, which is inconsistent with the scattered pilot positions FIG. 6 provides a chart of sub-carrier positions of continuous pilot symbols in 8k mode according to an example of the present invention; FIG. 7 provides sub-carrier positions of continuous pilot symbols in 8k mode according to an example of the present invention Explanation; FIG. 8 provides a histogram of the intervals of continuous pilot symbol subcarrier positions in an 8k mode according to an example of the present invention; FIG. 9 provides a Histogram of high-frequency vibration; FIG. 10 provides a chart of subcarrier positions of continuous pilot symbols in 16k mode according to an example of the present invention; FIG. 11 provides continuous pilot symbol subcarriers in 16k mode according to an example of the present invention Description of the carrier position; FIG. 12 provides a histogram of the intervals of the subcarrier positions of consecutive pilot symbols in the 16k mode according to an example of the present invention; FIG. 13 provides an illustration according to the present invention A chart of sub-carrier positions of continuous pilot symbols in 32k mode; FIG. 14 provides a description of sub-carrier positions of continuous pilot symbols in 32k mode according to an example of the present invention; and FIG. 15 provides 32k mode according to an example of the present invention. A histogram of the intervals of sub-carrier positions of consecutive pilot symbols of the pattern; FIG. 16 provides a flowchart of the operation of a transmitter according to an example of the present invention; and FIG. 17 provides a flowchart of the operation of a receiver according to an example of the present invention.

Figure 1 provides an example block diagram of an OFDM transmitter that can be used to transmit video images and audio signals, for example according to the proposed ATSC 3 standard or the DVB-T, DVB-H, DVB-T2 or DVB-C2 standard. In Figure 1, the program source generates the data transmitted by the OFDM transmitter. Video encoder 2 and audio encoder 4 and data encoder 6 generate video, audio, and other materials to be transmitted, which are fed to program multiplexer 10. The output of the program multiplexer 10 forms a multiplexed stream required for communication video, audio and other data. The multiplexer 10 provides a stream on the connection channel 12. There may be many such multiplexed streams which are fed to different branches A, B, etc. For simplicity, only branch A will be described.

As shown in FIG. 1, the OFDM transmitter 20 receives a stream in a multiplexer adaptation and energy dispersion block 22. The multiplexer adaptation and energy dispersion block 22 randomizes the data and feeds the appropriate data to a forwarding error correction encoder 24 that performs error correction encoding the stream. A bit interleaver 26 is provided to interleave the encoded data bits, an example of which is used in a DVB-T2 system is the LDCP / BCH encoder output. The output from the bit interleaver 26 is fed to a bit into the cluster mapper 28, which maps the bytes to a modulation architecture cluster that will be used to carry the encoded data bits Point. The output from this bit into the cluster mapper 28 is a cluster point label, which represents the actual and imaginary element. The cluster point label represents a data symbol formed from two or more bits attached to the modulation architecture used. These can be called data cells. These data cells are passed through a time-interleaver 30, whose function is to interleave data cells generated from multiple LDPC codewords.

The data cell line is received by the frame builder 32, and the data cell line through other channels 31 is manufactured by the branch B and the like in FIG. Frame builder 32 then forms a number of data cells into the sequence to carry OFDM symbols, where the OFDM symbols contain the number of data cells, each of which is mapped to one of a plurality of subcarriers. The number of subcarriers will depend on the mode of operation of the system, which may include one or more 8k, 16k, or 32k, each of which provides a different number of subcarriers and thus speeds up the Fourier Transform (FFT) size.

The sequence of data cells carried into each OFDM symbol is then passed to the symbol interleaver 33. The OFDM symbol is then generated by the OFDM symbol builder block 37. According to the pilot symbol pattern, the OFDM symbol builder block 37 introduces the pilot generated and fed by the pilot and embedded signal former 36. And synchronization signals. The OFDM modulator 38 then forms the OFDM symbol in the time domain, which is fed to a guard insertion processor 40 for generating a guard interval between the symbols, and then to a digital-to-analog converter 42, and Finally, the RF amplifier in the RF front-end 44 is used for final broadcasting from the antenna 46 by the COFDM transmitter.

Frame format

For the system of FIG. 1, the number of sub-carriers per OFDM symbol may vary depending on the number of pilots and other reserved carriers. An example description of the "super frame" is shown in Figure 2.

For example, in DVB-T2, unlike in DVB-T, the number of these subcarriers used to carry data is not fixed. The broadcast device can select one of the 1k, 2k, 4k, 8k, 16k, and 32k operation modes, each of which provides a range of subcarriers for the data of each OFDM symbol. The maximum for each of these modes is 1024, 2048, 4096, 8192, 16384, 32768. In DVB-T2, a physical layer frame is composed of many OFDM symbols. Generally, the frame starts with the preceding text or P1 symbol as shown in FIG. 2, which provides signaling information related to the configuration of the DVB-T2 deployment, including an indication of the mode. The P1 symbol is followed by one or more P2 OFDM symbols 64, which is then followed by the payload number of the OFDM symbol 66. The endpoints of the physical layer frame are marked by a frame close symbol (FCS) 68. For each mode of operation, the number of subcarriers may be different for each type of symbol. In addition, the number of subcarriers can be changed for each according to whether bandwidth extension is selected, whether band reservation is enabled, or whether pilot subcarrier patterns are selected.

Receiver

FIG. 3 provides an example illustration of an OFDM receiver that can be used to receive a transmitted signal from the transmitter shown in FIG. 1. Such as As shown in FIG. 3, the OFDM signal is received by the antenna 100 and detected by the tuner 102, and converted into a digital form by the analog-to-digital converter 104. The guard interval removal processor 106 removes the guard interval from the received OFDM symbols, at which the payload data and pilot data are obtained from the combination of a fast Fourier converter (FFT) processor 108 and a channel estimator and corrector 110. Before the OFDM symbol is restored, the embedded signal decoding unit 111 and the pilot symbol pattern. The demodulated data is recovered from the de-mapper 112 and fed to a symbol de-interleaver 114, which operates to reversely map the received data symbols to regenerate the output data stream with de-interleaved data. Similarly, the bit deinterleaver 116 reverses the bit interleaving performed by the bit interleaver 26. The rest of the OFDM receiver shown in FIG. 3 is provided to an effect error correction decoding 118 to correct errors and recover estimates of the source data.

An embodiment of the technology of the present invention provides a communication system that uses OFDM to transmit data and reuses many system designs and configuration parameters that have been used in the DVB-T2 standard. However, the communication system is suitable for transmitting OFDM symbols in a 6 MHz channel, instead of being used in the 8 MHz of the DVB T2 standard, and using 8k, 16k, and 32k modes. Therefore, the present invention discloses the application of the parameters for the OFDM system at 6 MHz, but rationalizes the parameters that may be developed for the DVB T2 standard to simplify the structure and implementation of the communication system.

Pilot symbol

In addition to transmission information and payload information, OFDM frames and their packets The enclosed cells may also contain pilot symbols that have been inserted into the transmitter. For example, these pilot symbols have been generated by the pilot and embedded signal former 36 and inserted by the symbol builder 37. Pilot symbols are transmitted at known amplitudes and phases, and the subcarriers transmitted according to them may be referred to as pilot subcarriers. Pilot symbols may need to be used for different purposes of the receiver, such as channel estimation, synchronization, coarse frequency offset estimation, and fine frequency offset estimation. Due to prior knowledge of the amplitude and phase of the pilot symbols, the channel impulse response can be estimated based on the received pilot symbols, and the estimated channel is then used for purposes such as equalization.

In order for the receiver to receive the pilot symbol and distinguish the pilot signal from other transmission symbols and data symbols, according to the subcarrier pilot symbol pattern, the pilot symbol can be distributed throughout all of the subcarriers and OFDM. Frame symbol. Therefore, if the receiver has knowledge of the pilot symbol pattern and is synchronized with the OFDM frame, it will be able to extract the received pilot symbols from the appropriate positions or subcarriers in the OFDM symbols and frame.

The distribution of pilots corresponding to OFDM subcarriers can be divided into two types: continuous pilots and scattered pilots. The continuous pilots are formed from pilot symbols, and the positions of the pilot symbols do not change from symbol to symbol with respect to the subcarriers, with the result that they are transmitted on the same subcarrier each time. Scattered pilot symbols roughly describe the change of pilot symbol position from symbol to symbol, possibly according to some repetitive patterns.

Figure 4 illustrates a series of OFDM symbols, where circles represent OFDM cells and gray circles represent pilot symbols. In FIG. 4, the horizontal direction represents the frequency or the number of subcarriers, and the vertical direction represents the time or the number of symbols. The continuous pilot symbols 120 are located on the same subcarrier (CP) each time, while the scattered pilots 122 are located on subcarriers that differ from symbol to symbol. The repetition of the scattered pilots can be represented by the variables Dx and Dy. Dx represents the separation between scattered pilots in the frequency domain from one OFDM symbol to another OFDM symbol, so that the scattered pilot symbols on the first OFDM symbol are replaced by the number of subcarriers, and the subcarriers The number of carriers is equal to Dx in the frequency domain on the subcarriers in the next OFDM symbol. Dy represents a parameter indicating the number of OFDM symbols that the same subcarrier is used again to carry before the next pilot symbol. For example, the locations where the pilot symbols are scattered in FIG. 4 may be represented by Dy = 8 and Dx = 10. Scattered pilots provide an effective way to pilot symbols because the channel estimates for subcarriers and symbols between scattered pilot symbols can be obtained from known pilot symbols or channel estimates by time and It is estimated by interpolation in both frequencies. Therefore, pilot symbols may not need to appear on all subcarriers to obtain channel estimates for each subcarrier and cell within the OFDM frame.

Pilot symbols occupy subcarriers and cells that can carry data. Therefore, the pilot symbols adversely affect the capacity of the system. It may be beneficial to minimize the number of pilot symbols. Therefore, a well-designed pilot pattern, its enabling channel estimation, etc. are obtained across the entire OFDM frame, while it is desirable to use a few pilot symbols.

The choice of a scattered pilot pattern for an OFDM signal may depend on many factors, such as the rate of channel change with respect to time and frequency. For example, the density of pilots must satisfy the sampling theorem in both time and frequency. If accurate channel estimates are obtained, for example, the maximum channel impulse response length is determined at The pilot symbols in the frequency direction are repeated, and the maximum Doppler frequency of the channel determines that the pilot symbols are repeated in the time domain. The guard interval in some example OFDM systems is determined by the length of the channel impulse response, and therefore pilot symbol repetition in the frequency direction may also depend on the guard interval period.

It may be beneficial if the positions of consecutive pilot symbols and scattered pilot symbols do not overlap or overlap, so that there is an approximately constant number of pilot symbols per frame and there are no significant "blind spots". There are a large number of adjacent cells in the OFDM frame that do not include pilot symbols. This area can be called a blind spot. It is often desirable to avoid this, as they may lead to reduced and interpolated accurate channel estimates, and may not be able to detect and compensate for colored noise, such as analog TV or other narrow-band interference. FIG. 5 provides a map of continuous pilot positions, which is not consistent with the scattered pilot positions in the DVB-T2 system, and illustrates the above-mentioned problem, in which the area shown by the blind spot 124 has missing pilot symbols. Also at the edges of the band 126 shown in FIG. 5, where measurements made by pilot symbols on these areas may be subject to increased noise and attenuation, and therefore should be avoided if possible.

其中CPnSP表示連續導頻符號數，連續導頻符號數在OFDM訊框期間與散佈導頻子載波不一致。因此，由於上述的原因，嘗試和最大化該產能利用率可能是有益的。也 有一些可以具有決定散佈導頻和連續導頻圖案時，必須考慮到的其它因素，例如，具有靠近OFDM信號之外部子載波的導頻符號則可能不為有用的，因為很可能是這些子載波可能係在調諧濾波器的過渡帶內，並遭受到上述額外的噪音。在一定程度上隨機化導頻符號之位置也可能是有益的，以確保干擾被適當地建模並獲得可靠的通道估計。此外，由於散佈導頻之相依因素，像是防護間隔的持續時間和多普勒擴展，OFDM系統可具有可用的複數個導頻圖案，每個由重複率Dx和Dy所指定。 The measurement of the extension of the coincidence of continuous pilot symbols and scattered pilot symbols can be called the utilization rate, and can be calculated using the following formula

CPnSP represents the number of continuous pilot symbols, and the number of continuous pilot symbols is inconsistent with the scattered pilot subcarriers during the OFDM frame period. Therefore, for the reasons described above, it may be beneficial to try and maximize this capacity utilization. There are other factors that must be considered when deciding on the pilot and continuous pilot patterns. For example, pilot symbols with external subcarriers close to the OFDM signal may not be useful because it is likely that these subcarriers are May be in the transition band of a tuned filter and suffer from the additional noise described above. It may also be beneficial to randomize the position of the pilot symbols to some extent to ensure that the interference is properly modeled and a reliable channel estimate is obtained. In addition, due to the dependent factors of the scattered pilots, such as the duration of the guard interval and the Doppler spread, the OFDM system may have a plurality of available pilot patterns, each of which is specified by the repetition rates Dx and Dy.

Due to possible changes in the spreading pilot pattern, in order to maximize utilization, minimize blind spots, and prevent pilot symbols from being placed close to external subcarriers, different continuous pilot patterns for spreading one or more pilots may be required . For example, in DVB-T2, in some modes, there are eight scattered pilot patterns and eight corresponding continuous pilot patterns. In some OFDM systems, there may be more than one pattern per mode, and different patterns across different modes, so that there may be a large number of pilot patterns in total.

The pilot signal embedder 36, which embeds pilot symbols in a transmitter, and the pilot signal extractor 111, which extracts pilot symbols in a receiver, require knowledge of pilot patterns. Therefore, it is possible that all the pilot patterns that can be used in the system will have to be stored in the ROM of both the transmitter and the receiver, so a significant amount of memory is required. If there are multiple modes and multiple Pilot pattern. This memory requirement is particularly relevant for receivers in broadcast systems, as there are more likely to be a large number of receivers than transmitters, and the cost of the receiver is likely to be lower than the transmitter. So reduce memory The requirements may be advantageous, especially for receiver-side systems.

In addition to the memory requirements, the use of a large number of different spreading and continuous pilot patterns in the system also complicates the system because the transmitter must choose which pilot mode is most suitable for the current channel conditions and signal attributes, and the receiving The machine needs to identify the pilot pattern to be used. The receiver can do this via signaling information specifying the pilot pattern and operation mode, or the receiver can detect the pattern and pilot pattern via the characteristics of the signal. However, these two methods become more complicated and have greater overhead when there are more pilot patterns in a system. Therefore, it is desirable to reduce the number of pilot patterns used to simultaneously maximize utilization in a system, avoid blind spots, and minimize the number of pilots of neighboring external subcarriers.

According to an example of the technology of the present invention, an OFDM system with a 6 MHz bandwidth and 8k, 16k, 32k modes has a single continuous pilot subcarrier pattern for each mode, which is suitable for a plurality of different scattered pilot symbols in each mode Use with patterns. In one example, a continuous pilot pattern is suitable for use with one or more scattered pilot patterns given in Table 2 below.

In the 8k mode (normal or extended) of the OFDM system, which uses the given pilot sequence given in Table 2 above, the distribution of continuous pilots can be given by the table in FIG. 6. As shown in Figure 6, the same position, as far as the subcarrier position in the extended bandwidth mode is determined by 41, 173, 357, 505, 645, 805, 941, 1098, 1225, 1397, 1514, 1669, 1822, 1961, 2119, 2245, 2423, 2587, 2709, 2861, 3026, 3189, 3318, 3510, 3683, 3861, 4045, 4163, 4297, 4457, 4598, 4769, 4942, 5113, 5289, 5413, 5585, 5755,5873,6045,6207,6379,6525,6675,6862. For operation in normal 8k mode, the pilot pattern can be derived by discarding the last subcarrier position. Relative to the subcarriers given in FIG. 6, the positions of the continuous pilot symbols are not consistent with the positions of the scattered pilots given in Table 2 above, and therefore, the continuous pilot pattern obtains 100% utilization. FIG. 7 illustrates the positions of the continuous pilots for the extended 8k mode of FIG. 6 and the continuous pilots showing a substantially uniform distribution across the subcarriers of the extended 8k mode, which does not have any substantial blind spots. Figure 8 provides a histogram of consecutive pilot symbols relative to the subcarrier spacing. The histogram again shows that there are consecutive pilot symbols that are distributed substantially uniformly across all subcarriers, thus strengthening the lack of blind spots. Although the distribution of the pilot symbols distributed on all the subcarriers is substantially uniform, their positions have been randomized to some extent by the introduction of high frequency vibration (Dither). FIG. 9 shows high-frequency vibrations that have been applied to the placement of the continuous pilot symbols in FIG. 6.

Utilization in 16k mode (normal or extended) of OFDM systems Given the scattered pilot sequences in Table 2, the distribution of consecutive pilots can be given by the table in Figure 10. The same position as given in Figure 10, as far as the position of the subcarriers in the extended bandwidth mode is composed of 82, 243, 346, 517, 714, 861, 1010, 1157, 1290, 1429, 1610, 1753, 1881, 2061, 2197, 2301, 2450, 2647, 2794, 2899, 3027, 3159, 3338, 3497, 3645, 3793, 3923, 4059, 4239, 4409, 4490, 4647, 4847, 5013, 5175, 5277, 5419, 5577, 5723, 5895, 6051, 6222, 6378, 6497, 6637, 6818, 7021, 7201, 7366, 7525, 7721, 7895, 8090, 8199, 8325, 8449, 8953, 8743, 8915, 9055, 9197, 9367, 9539, 9723, 9885, 10058, 10226, 10391, 10578, 10703, 10825, 10959, 11169, 11326, 11510, 11629, 11747, 11941, 12089, 12243, 12414, 12598, 12758, 12881, 13050, 13195, 13349, 13517, 13725, 13823. For operation in normal 16k mode, the pilot pattern can be derived by discarding the last two subcarrier positions. Relative to the subcarriers given in FIG. 10, the positions of the continuous pilot symbols are not consistent with the positions of the scattered pilots given in Table 2 above, and therefore, the continuous pilot pattern obtains 100% utilization. FIG. 11 illustrates the positions of the continuous pilots for the extended 16k mode of FIG. 10 and the continuous pilots showing a substantially uniform distribution across the subcarriers of the extended 16k mode, which does not have any substantial blind spots. FIG. 12 provides a histogram of consecutive pilot symbols with respect to subcarrier spacing. The histogram again shows continuous pilot symbols that are distributed substantially uniformly across all subcarriers, thus strengthening blind spots Lack of. For the 8k mode, although the distribution of pilot symbols on all subcarriers is substantially uniform, their positions have been randomized to some extent by the introduction of high-frequency vibration. The same high-frequency vibration as the placement applied to the 8k continuous pilot symbols is also applied to the placement of the 16k continuous pilot symbols. Therefore, FIG. 9 illustrates the height of the continuous pilot symbols that have been applied in FIG. 10. Frequency vibration.

In the 32k mode of the OFDM system, which uses the scattered pilot sequence given in Table 2 above, the distribution of continuous pilots can be given by, for example, the table in FIG. 13. The same position as given in FIG. 13 is represented by 163, 290, 486, 605, 691, 858, 1033, 1187, 1427, 1582, 1721, 1881, in terms of subcarrier positions in the extended bandwidth mode. 2019, 2217, 2314, 2425, 2579, 2709, 2857, 3009, 3219, 3399, 3506, 3621, 3762, 3997, 4122, 4257, 4393, 4539, 4601, 4786, 4899, 5095, 5293, 5378, 5587, 5693, 5797, 5937, 6054, 6139, 6317, 6501, 6675, 6807, 6994, 7163, 7289, 7467, 7586, 7689, 7845, 8011, 8117, 8337, 8477, 8665, 8817, 8893, 8979, 9177, 9293, 9539, 9693, 9885, 10026, 10151, 10349, 10471, 10553, 10646, 10837, 10977, 11153, 11325, 11445, 11605, 11789, 11939, 12102, 12253, 12443, 12557, 12755, 12866, 12993, 13150, 13273, 13445, 13635, 13846, 14041, 14225, 14402, 14571, 14731, 14917, 15050, 15209, 15442, 15622, 15790, 15953, 16179, 16239, 16397, 16533, 16650, 16750, 16897, 17045, 17186, 17351, 17485, 17637, 17829, 17939, 18109, 18246, 18393, 18566, 18733, 18901, 19077, 19253, 19445, 19589, 19769, 19989, 20115, 20275, 20451, 20675, 20781, 20989, 21155, 21279, 21405, 21537, 21650, 21789, 21917, 22133, 22338, 22489, 22651, 22823, 23019, 23205, 23258, 23361, 23493, 23685, 23881, 24007, 24178, 24317, 24486, 24689, 24827, 25061, 25195, 25331, 25515, 25649, 25761, 25894, 26099, 26246, 26390, 26569, 26698, 26910, 27033, 27241, 27449, 27511, 27642, 27801 given. The pilot pattern used to operate in the normal 32k mode can be derived by discarding the last four subcarrier positions. With respect to the subcarriers given in FIG. 14, the positions of the continuous pilot symbols are not consistent with the positions of the scattered pilots given in Table 2 above, and therefore, the continuous pilot pattern obtains 100% utilization. FIG. 14 illustrates the positions of the continuous pilots for the extended 32k mode of FIG. 13 and the continuous pilots showing a substantially uniform distribution across the subcarriers of the extended 8k mode, which does not have any substantial blind spots. Figure 15 provides a histogram of consecutive pilot symbols relative to the subcarrier spacing. The histogram again shows that there are consecutive pilot symbols that are distributed substantially uniformly across all subcarriers, thus strengthening the lack of blind spots. For 8k and 16k modes, although the distribution of the pilot symbols of the subcarriers on all subcarriers is substantially uniform, it Their positions have been randomized to some extent by the introduction of high-frequency vibrations. The same high-frequency vibration as the placement of 8k and 16k continuous pilot symbols is also applied to the placement of 32k continuous pilot symbols. Therefore, FIG. 9 illustrates the continuous pilot symbols that have been applied in FIG. 13. High-frequency vibration.

As mentioned earlier, the continuous pilot patterns suggested above can also achieve a substantially 100% utilization rate, however, they also achieve about 0.65% capacity loss in the system, like the ATSC suggested previously 3 systems.

The continuous pilot pattern referred to above may provide advantages over existing continuous pilot patterns because only a single continuous pilot pattern is required to operate with the five scattered pilots specified in Table 2. In addition, these pilot patterns also reduce the number of blind spots compared to continuous pilot patterns, such as those specified in DVB-T2. Because compared to five (if the conventional continuous pilot pattern is used), only one continuous pilot pattern needs to be stored in both the transmitter and the receiver, the memory requirement has been reduced by about 80%. However, memory for multiple consecutive pilot patterns may still be required when more than one mode of operation, such as 8k, 16k, 32k, and normal and extended modes are available. Therefore, in a system such as the proposed ATSC 3 system, there are three modes, and it may be that three consecutive pilot patterns still need to be stored.

According to another example of the present technology, the continuous pilot patterns illustrated in FIG. 6, FIG. 10, and FIG. 13 are related so that the continuous pilot patterns of 8k and 16k modes are derived from the continuous pilot symbol patterns of 32k mode . Therefore, this allows the transmitter and receiver to store only one Primarily continuous pilot patterns, and then when they are needed, a continuous pilot pattern for lower order modes is derived.

For example, the pilot and embedded signal generator 36 at the transmitter may include a processor that is operable to detect or receive data, which communicates the mode of operation of the OFDM system, and then derives from the main pilot pattern based on the number of subcarriers A suitable continuous pilot pattern, wherein the main pilot pattern is stored in the memory of the pilot and embedded signal former 36. In the case of the continuous pilot pattern discussed above, the main continuous pilot pattern will be a 32k pilot pattern and a 16k continuous pilot pattern, and according to the following equation, the 8k continuous pilot pattern will be processed by the processor Derived from the 32k pilot pattern, where the main pilot is given by the next subcarrier position and is used to extend the bandwidth mode: 163, 290, 486, 605, 691, 858, 1033, 1187, 1427, 1582 , 1721, 1881, 2019, 2217, 2314, 2425, 2579, 2709, 2857, 3009, 3219, 3399, 3506, 3621, 3621, 3762, 3997, 4122, 4257, 4393, 4539, 4601, 4786, 4899, 5095, 5293 , 5378,5587,5693,5797,5937,6054,6139,6317,6501,6675,6807,6994,7163,7289,7467,7586,7689,7845,8011,8117,8337,8477,8665,8817,8893 , 8979, 9177, 9293, 9539, 9693, 9885, 10026, 10151, 10349, 10471, 10553, 10646, 10837, 10977, 11153, 11325, 11445, 11605, 11789, 11939, 12102, 12253, 12443, 12557, 12755 , 12866, 12993, 13150, 13273, 13445, 13635, 13846, 14041 14225,14402,14571,14731, 14917, 15050, 15209, 15442, 15622, 15790, 15953, 16179, 16239, 16397, 16533, 16650, 16750, 16897, 17045, 17186, 17351, 17485, 17637, 17829, 17939, 18109, 18246, 18393, 18566, 18733, 18901, 19077, 19253, 19445, 19589, 19769, 19989, 20115, 20275, 20451, 20675, 20781, 20989, 21155, 21279, 21405, 21537, 21650, 21789, 21917, 22133, 22338, 22489, 22651, 22823, 23019, 23205, 23258, 23361, 23493, 23685, 23881, 24007, 24178, 24317, 24486, 24689, 24827, 25061, 25195, 25331, 25515, 25649, 25761, 25894, 26099, 26246, 26390, 26569, 26698, 26910, 27033, 27241, 27449, 27511, 27642, 27801.

In order to derive a 16k continuous pilot position from the 32k pilot position given above in FIG. 13 and every 32k continuous pilot position is taken, the position is divided by 2 and the result is rounded up. As far as a computer implementable equation is concerned, this is given by CP_16K_pos = round (CP_33K_pos (1: 2: last_32k_cp_pos) / 2).

In order to derive 8k continuous pilot positions from the 32k pilot positions given above in FIG. 13 and every 4 times of the 32k continuous pilot positions, the fetched position is divided by 4 and the result is rounded up. For a computer implementable equation, this is given by

CP_8K_pos = round (CP_32K_pos (1: 4: last_32k_cp_pos) / 4).

Using the above equation is possible, 8k, 16k, and 32k continuous pilot patterns can be derived from a single main set, so the OFDM system is effectively able to operate with a single continuous pilot pattern that spans all modes and all scattered pilot patterns. Therefore, in terms of memory requirements, this can simplify the operation of the OFDM system, but still requires program processing, because it no longer needs to switch between unrelated independent continuous pilot patterns.

Although the derivation of the continuous pilot pattern in the previous paragraph occurs in the transmitter, similar procedures can be performed in the receiver. For example, the embedded signal decoding unit 111 further includes a processor, which is basically similar to the processor described with reference to the pilot and the embedded signal former 36. The processor will be operable to detect or receive data conveying the mode of operation of the OFDM system, that is, the number of subcarriers per OFDM symbol, and then derive a suitable continuous pilot pattern from the main pilot pattern described previously.

Due to the simplicity of the calculation of the above derivation process, the reduction in ROM memory requirements, that is, the memory needs to store 8k and 16k continuous pilot patterns, can be achieved with only a small, increased computational complexity. In some examples, derivation at the transmitter and receiver may be performed by existing computational elements within the pilot-related elements according to current technology, and therefore no additional components are required in these cases.

In other examples of the technology according to the present invention, continuous pilot symbols for 8k, 16k, and 32k modes can be used in OFDM systems, such as ATSC 3.0 systems, for example, to take advantage of the inherent advantages of continuous pilot symbol patterns Potential. For example, there are advantages of the normal distribution of pilot positions and the reduction in pilot positions close to external subcarriers, which can be achieved by a continuous pilot subcarrier pattern, which has the following index: for 8k mode 41, 173, 357, 505, 645, 805, 941, 1098, 1225, 1397, 1514, 1669, 1822, 1961, 2119, 2245, 2423, 2587, 2709, 2861, 3026, 3189, 3318, 3510, 3683, 3861, 4045, 4163, 4297, 4457, 4598, 4769, 4942, 5113, 5289, 5413, 5585, 5755, 5873, 6045, 6207, 6379, 6525, 6675, (6862); 82, 243 for 16k mode , 346, 517, 714, 861, 1010, 1157, 1290, 1429, 1610, 1753, 1881, 2061, 2197, 2301, 2450, 2647, 2794, 2899, 3027, 3159, 3338, 3497, 3645, 3793, 3923 , 4059, 4239, 4409, 4490, 4647, 4847, 5013, 5175, 5277, 5419, 5577, 5723, 5895, 6051, 6222, 6378, 6497, 6637, 6818, 7021, 7201, 7366, 7525, 7721, 7895 , 8090, 8199, 8325, 8449, 8953, 8743, 8915, 9055, 9197, 9367, 9539, 9723, 9885, 10058, 10226, 103 91, 10578, 10703, 10825, 10959, 11169, 11326, 11510, 11629, 11747, 11941, 12089, 12243, 12414, 12598, 12758, 12881, 13050, 13195, 13349, 13517, (13725, 13823); and 163, 290, 486, 605, 691, 858, 1033, 1187, 1427, 1582, 1721, 1881, 2019, 2217, 2314, 2425, 2579, 2709, 2857, 3009, 3219, 3399, 32k mode 3506, 3621, 3762, 3997, 4122, 4257, 4393, 4539, 4601, 4786, 4899, 5095, 5293, 5378, 5587, 5693, 5797, 5937, 6054, 6139, 6317, 6501, 6675, 6007, 6994, 7163, 7289, 7467, 7586, 7689, 7845, 8011, 8117, 8337, 8477, 8665, 8817, 8893, 8979, 9177, 9293, 9539, 9693, 9885, 10026, 10151, 10349, 10471, 10553, 10646, 10837, 10977, 11153, 11325, 11445, 11605, 11789, 11939, 12102, 12253, 12443, 12557, 12755, 12866, 12993, 13150, 13273, 13445, 13635, 13846, 14041, 14225, 14402, 14571, 14731, 14731, 14917, 15050, 15209, 15442, 15622, 15790, 15953, 16179, 16239, 16397, 16533, 16650, 16750, 16897, 17045, 17186, 17351, 17485, 17637, 17829, 17939, 18109, 18246, 18393, 18566, 18733, 18901, 19077, 19253, 19445, 19589, 19769, 19989, 20115, 20275, 20451, 20675, 20781, 20989, 21155, 21279, 21405, 21537, 21650, 21789, 21917, 22133, 22338, 22489, 22651, 22823, 23019, 23205, 23258, 23361, 2349 3, 23685, 23881, 24007, 24178, 24317, 24486, 24689, 24827, 25061, 25195, 25331, 25515, 25649, 25761, 25894, 26099, 26246, 26390, 26569, 26698, 26910, 27033, 27241, (27449 , 27511, 27642, 27801), where the value and frequency in the bracket Wide mode related.

Operation summary

An example flowchart of the operation of a transmitter according to the technology of the present invention is shown in FIG. 16, and the operation of the receiver is to detect and recover data from the received OFDM symbols provided in FIG. The program steps shown in Figure 15 are as follows:

S1: As a first step, data is transmitted using OFDM symbols. A data formatter receives data for transmission, and forms data into a data symbol set for each OFDM symbol used for transmission. Therefore, data symbols are formed into the sets, each of which has a number of data symbols corresponding to the amount of data that can be carried by the OFDM symbol.

S2: The OFDM symbol builder then receives a set of individual data symbols from the data formatter, and combines the data symbols and pilot symbols according to a predetermined spread and continuous pilot pattern. According to the technology of the present invention, the pilot pattern is given by Table 2 for dispersing pilots and Figures 6, 10 and 13 for continuous pilots, where the subcarrier positions in Figures 6 and 10 can be Derived from the position in FIG. 13. A predetermined pattern sets a subcarrier of an OFDM symbol carrying a pilot symbol. The remaining subcarriers of the OFDM symbol carry data symbols. The OFDM symbols therefore each include a plurality of subcarrier symbols, some subcarrier symbols carrying data symbols, and some subcarrier symbols carrying pilot symbols.

S4: The modulator maps the data symbol and the pilot symbol to the modulation symbol according to the values of the data symbol and the pilot symbol. With modulation symbols, each subcarrier system is then modulated to form an OFDM symbol in the frequency domain.

S6: The inverse Fourier converter then converts the OFDM symbols in the frequency domain into the time domain within the bandwidth of the communication system of 6 MHz or about 6 MHz.

S8: The guard interval inserter adds a guard interval to each time-domain OFDM symbol by copying a part of the OFDM symbol. It contains a useful part of the data symbol or pilot symbol and will be sequentially used in the time domain. The copied part is appended to the OFDM symbol. The copied portion has a length corresponding to the guard interval, which is a predetermined guard interval period.

S10: The radio frequency transmitting unit then modulates a radio frequency carrier having a time domain OFDM symbol, and transmits the OFDM symbol via the antenna of the transmitter.

The operation of the receiver is to detect and recover data from the OFDM symbols transmitted by the transmission method as shown in FIG. 17, and the summary is as follows:

S12: The demodulator receives a signal from an antenna and a radio frequency down converter, and detects a signal representing an OFDM symbol. The demodulator generates a digital version of the sampled time domain of the OFDM symbol. The technology according to the present invention is basically 6 MHz, which is the bandwidth of OFDM symbols in the frequency domain of about 6 MHz.

S14: The guard interval correlator correlates a set of samples corresponding to the guard interval of the OFDM symbol to detect timing of a useful part of the OFDM symbol. A section of a received signal sample corresponding to the guard interval is copied and stored, and then correlated with respect to the same received signal sample to detect a correlation peak in which a repeated guard interval exists in a useful part of the OFDM symbol.

S16: Fourier transform processor, followed by guard interval correlator A useful part of the OFDM symbol identified at the detected time is to convert a segment of the time domain samples of the received signal into the frequency domain using a Fourier transform. From OFDM symbols in the frequency domain, pilot symbols can be recovered from pilot symbols carrying subcarriers, and data symbols can be recovered from data carrying subcarriers. According to the technology of the present invention, the pilot subcarrier positions are given in Table 2 for spreading pilots and Figures 6, 10 and 13 for continuous pilots, where the subcarriers in Figures 6 and 10 The position of the carrier can be derived from the position given in FIG.

S18: The channel estimation and correction unit estimates the channel impulse response, passes through the place where the OFDM symbol has passed from the recovered pilot symbol, and corrects the received data, which carries the subcarriers using the estimated channel impulse response. Usually this is based on the equalization technique of the received signal in the frequency domain, which is divided by the frequency domain representation of the channel impulse response.

S20: The resolver recovers the data symbols from the data of the subcarriers carrying the OFDM symbols by performing reverse mapping to the data transmitted on the transmitter.

It is understood that the transmitters and receivers shown in Figures 1 and 3 respectively are provided as illustrations only and are not intended to be limiting. For example, it can be understood that the technology of the present invention can be applied to different transmitter and receiver architectures.

As mentioned above, embodiments of the present invention are applicable to ATSC standards, such as ATSC 3.0, which are incorporated herein by reference. For example, embodiments of the present invention can be used in a transmitter or receiver that operates in accordance with a handheld mobile terminal. Available services may include voice, messaging, web browsing, radio, still and / or mobile video, television services, interactive services, Video or nearby-needs and options on video. The service may operate with another combination.

Claims (21)

A receiver configured to recover data from orthogonal frequency division multiplexing (OFDM) symbols, the OFDM symbols including a complex subcarrier signal, some carrying data symbols of the subcarrier signals, and some carrying of the subcarrier signals Pilots, the pilots include continuous pilots, the continuous pilots are distributed on all the subcarrier signals according to a continuous pilot pattern, and the continuous pilot pattern is selected from the group including a first continuous pilot A pattern and a complex continuous pilot pattern of at least one second continuous pilot pattern derived from the first continuous pilot pattern, the receiver includes: a demodulator configured to detect signals representing the OFDM symbols, and In the time domain, a digital version of the time domain samples of the OFDM symbols is generated, the processor is converted, and configured to receive the time digital version of the OFDM symbols and form the frequency domain version of the OFDM symbols, thereby The subcarrier signals carrying the pilot, the subcarrier signals carrying the data, and the detector are configured to determine the number of subcarrier signals in the plurality of subcarrier signals, based on the subcarriers. Numeral to decide the plurality of consecutive OFDM symbols of the pilot pattern, and to restore the material from the plurality of subcarrier signals and the plurality of pilot. The receiver according to item 1 of the scope of patent application, wherein the continuous pilot pattern of each of the OFDM symbols is selected according to the number of the subcarrier signals of each of the OFDM symbols, and the subcarrier signal The number is one of a group of subcarrier signals, and the group of subcarrier signals includes a number of first subcarrier signals for selecting the first continuous pilot pattern and a number of subcarrier signals for selecting the at least one second continuous pilot pattern. The number of at least one second subcarrier signal, and the number of the first subcarrier signal are greater than the number of the at least one second subcarrier signal. The receiver according to item 2 of the patent application range, wherein: the number of subcarrier signals in the group includes approximately 8k, 16k, and 32k, and the continuous pilot patterns for 8k and 16k subcarrier signals are used for 32k This continuous pilot pattern of the subcarrier signal is derived. The receiver according to item 3 of the patent application scope, wherein the number of pilots in the continuous pilot pattern for the 8k subcarrier signal is at least 45, and the pilots in the continuous pilot pattern for the 16k subcarrier signal The number of frequencies is at least 90, and the number of pilots in the continuous pilot pattern for a 32k subcarrier signal is at least 180. The receiver as described in claim 3, wherein the detector is configured to determine the continuous pilot pattern according to one or more of the following equations: CP_8K_pos = round (CP_32K_pos (1: 4: last_32k_cp_pos) / 4), CP_16K_pos = round (CP_32K_pos (1: 2: last_32k_cp_pos) / 2), where CP_8K is the continuous pilot pattern for 8k subcarrier signals, and CP_16K is the continuous pilot pattern for 16k subcarrier signals , And CP_32K are the continuous pilot patterns for 32k subcarrier signals. The receiver according to item 1 of the patent application scope, wherein the detector is configured to determine the sub-carrier by using transmission information received with the OFDM symbols or by detecting one or more signal characteristics The number of signals. The receiver according to item 1 of the patent application range, wherein the pilots include scattered pilots that are distributed over all of the subcarrier signals according to one of the complex scattered pilot patterns having the following repetition parameters: Dx = 4, Dy = 2; Dx = 4, Dy = 4; Dx = 8, Dy = 2; Dx = 16, Dy = 2; or Dx = 32, Dy = 2. The receiver according to item 1 of the patent application range, wherein the pilots include scattered pilots having positions that are inconsistent with the positions of the consecutive pilots. The receiver according to item 1 of the scope of patent application, wherein the pilots include scattered pilots that are distributed over all of the subcarrier signals according to a scattered pilot pattern that is independent of the continuous pilot pattern. The receiver according to item 1 of the patent application range, wherein the OFDM symbols include a first OFDM symbol and a second OFDM symbol, the first OFDM symbols include a first number of subcarrier signals, and the second OFDM symbols include The number of second subcarrier signals, the number of second subcarrier signals being the same as or greater than the number of first subcarrier signals, wherein the consecutive pilots are present in the first OFDM symbols and the second OFDM symbols On the same subcarrier position. A method for recovering data from orthogonal frequency division multiplexing (OFDM) symbols, the OFDM symbols include a plurality of subcarrier signals, some of the subcarrier signals carry data, and some of the subcarrier signals carry pilots, The pilots include continuous pilots, which are distributed on all of the subcarrier signals according to a continuous pilot pattern. The continuous pilot pattern is selected from the group consisting of a first continuous pilot pattern and from The complex continuous pilot pattern of at least one second continuous pilot pattern derived from the first continuous pilot pattern. The method includes: detecting a signal representing the OFDM symbols; and generating a digital version of the OFDM symbols in the time domain. Receiving the time-domain digital version of the OFDM symbols and forming the frequency-domain version of the OFDM symbols, thereby recovering the subcarrier signals carrying pilots and the subcarrier signals carrying data; determining the complex numbers The number of subcarrier signals in the subcarrier signals is based on the number of subcarrier signals to determine the continuous pilot patterns of the OFDM symbols, and the data and the pilots are restored from the subcarrier signals. The method according to item 11 of the scope of patent application, wherein: the continuous pilot pattern of each of the OFDM symbols is selected according to the number of subcarrier signals of each of the OFDM symbols, and the number of subcarrier signals It is one of a group of subcarrier signals, and the group of subcarrier signals includes at least a number of first subcarrier signals for selecting the first continuous pilot pattern and at least one for selecting the at least one second continuous pilot pattern. A number of second subcarrier signals, and the number of first subcarrier signals is greater than the number of at least one second subcarrier signal. The method according to item 11 of the scope of patent application, wherein the number of subcarrier signals in the group includes approximately 8k, 16k, and 32k, and the continuous pilot patterns for 8k and 16k subcarrier signals are used for 32k subcarriers. The continuous pilot pattern of the carrier signal is derived. The method according to item 13 of the scope of patent application, wherein the number of pilots in the continuous pilot pattern for the 8k subcarrier signal is at least 45, and the number of pilots in the continuous pilot pattern for the 16k subcarrier signal Is at least 90, and the number of pilots in the continuous pilot pattern for a 32k subcarrier signal is at least 180. The method according to item 13 of the scope of patent application, wherein the continuous pilot pattern is determined according to one or more of the following equations: CP_8K_pos = round (CP_32K_pos (1: 4: last_32k_cp_pos) / 4), CP_16K_pos = round (CP_32K_pos (1: 2: last_32k_cp_pos) / 2), where CP_8K is the continuous pilot pattern for 8k subcarrier signals, CP_16K is the continuous pilot pattern for 16k subcarrier signals, and CP_32K is used for 32k The continuous pilot pattern of the subcarrier signal. The method according to item 11 of the scope of patent application, wherein determining the number of sub-carrier signals includes using transmission information received with the OFDM symbols or detecting one or more signal characteristics. The method as described in item 11 of the scope of patent application, wherein the pilots include scattered pilots that are distributed over all of the subcarrier signals according to one of the complex scattered pilot patterns having the following repetition parameters: Dx = 4, Dy = 2; Dx = 4, Dy = 4; Dx = 8, Dy = 2; Dx = 16, Dy = 2; or Dx = 32, Dy = 2. The method according to item 11 of the scope of patent application, wherein the pilots include scattered pilots having positions that are inconsistent with the positions of the consecutive pilots. The method according to item 11 of the scope of patent application, wherein the pilots include scattered pilots that are distributed over all of the subcarrier signals according to a scattered pilot pattern that is independent of the continuous pilot pattern. The method according to item 11 of the scope of patent application, wherein the OFDM symbols include a first OFDM symbol and a second OFDM symbol, the first OFDM symbols include a first number of subcarrier signals, and the second OFDM symbols include a first The number of two subcarrier signals, the number of the second subcarrier signals being the same as or greater than the number of the first subcarrier signals, wherein the continuous pilots are present in the first OFDM symbols and the second OFDM symbols On the same subcarrier position. A non-transitory computer-readable medium stores a computer program having computer-executable instructions. When executed by a computer, the instructions cause the computer to execute the method described in item 11 of the scope of patent application.