A detection method and device based on HPLC dual-mode wireless system

Abstract

The application relates to a sweep frequency method, a detection method and a device based on an HPLC dual-mode wireless system, and belongs to the technical field of power line carrier communication and wireless communication, and comprises the following steps: determining that the current wideband channel environment is a DTMB channel environment; determining a subchannel number list in a DTMB channel interval according to a DTMB channel opening condition; sequentially performing sweep frequency processing on the subchannel number list in the DTMB channel interval, and when a subchannel that can be accessed is detected, the sweep frequency ends; otherwise, a center frequency point list of the DTMB channel is determined according to the DTMB channel opening condition; sequentially performing sweep frequency processing on the center frequency point list of the DTMB channel, and when a subchannel that can be accessed is detected, the sweep frequency ends. The application can improve the sweep frequency efficiency by preferentially performing sweep frequency on the subchannel number list in the DTMB interval and then performing sweep frequency on the center frequency point list of the DTMB channel; and the application can efficiently and accurately obtain a communication mode of the coincident subchannel number according to the channel correlation of the LTF.

Description

Technical Field

[0001] This invention relates to a frequency sweeping method, detection method, and apparatus based on an HPLC dual-mode wireless system, belonging to the fields of power line carrier communication and wireless communication technology. Background Technology

[0002] With the development of technology, the Internet of Things (IoT), smart homes, smart meters, and remote monitoring are increasingly penetrating people's daily lives. These applications all require data transmission during use, and a common data transmission method is High-speed Power Line Carrier (HPLC). HPLC, also known as broadband power line carrier, is a broadband power line carrier technology that transmits data over low-voltage power lines. Broadband power line carrier communication networks use power lines as the communication medium to achieve the aggregation, transmission, and interaction of electricity consumption information for low-voltage power users. It primarily employs Orthogonal Frequency Division Multiplexing (OFDM) technology, using a frequency band of 2MHz to 12MHz. However, the above method cannot achieve data transmission in wireless space. Therefore, existing technologies have proposed HPLC dual-mode systems, which are communication modules or devices that use both High-speed Power Line Carrier (HPLC) and High-speed Wireless Communication (HRF) technologies for data transmission.

[0003] A communication system employing high-speed wireless communication technology in a dual-mode HPLC system for data transmission (hereinafter referred to as the HPLC dual-mode wireless system) is a broadband carrier technology for data transmission in wireless space, supplementing high-speed power line carrier technology. It also uses Orthogonal Frequency Division Multiplexing (OFDM) technology, supporting a communication frequency band of 470MHz–510MHz. The quality of wired HPLC links is generally evaluated using the Signal-to-Noise Ratio (SNR), while wireless RF is measured using the Received Signal Strength Indicator (RSSI) and SNR. In the HPLC dual-mode wireless system, the HPLC communication network consists of a Central Coordinator (CCO), Proxy Coordinators (PCOs), and Stations (STAs). The CCO and PCO are responsible for network control and maintenance management, while the STAs are responsible for terminal data acquisition and transmission. The PCO and CCO in the communication network require upgrades.

[0004] In the prior art, each HPLC communication network includes one CCO and multiple STAs. The CCO needs to acquire its corresponding channel (to send wireless signals) to transmit data, that is, to send data after accessing the channel. The STA needs to select the channel that has transmitted the HPLC wireless signal (to receive wireless signals) to receive data, that is, to receive data after accessing the channel.

[0005] The HPLC dual-mode wireless system is a burst signal system, and its physical layer frame structure is shown in the attached manual. Figure 1 As shown, the training field includes a short training field (STF) and a long training field (LTF) for the preamble signal. The preamble signal is the leading part of the burst signal. The signal part includes the signal (SIG), the Physical Layer Frame Header (PHR), and the Physical Layer Service Data Unit (PSDU). The STF can be used by the terminal to detect the position of the frame header and fractional frequency offsets, while the LTF can be used by the terminal to detect integer frequency offsets and perform frequency domain channel estimation. The channel response is then determined through channel estimation.

[0006] According to the requirements of the Radio Administration Bureau of the Ministry of Industry and Information Technology, the operating frequency for "civilian metering instruments" type low-power wireless devices is 470–510 MHz, with wireless channel bandwidths defined as 200 kHz, 500 kHz, or 1000 kHz, and multiple channels allocated according to the bandwidth. For the aforementioned 470–510 MHz band, the main wireless broadcasting service of the broadcasting industry is Digital Terrestrial Multimedia Broadcast (DTMB), while other services involving short-range devices also exist. DTMB has five service channels, each with an effective bandwidth of 7.56 MHz and a channel spacing of 8 MHz. The center frequency information for each service channel is as follows: 474 MHz, 482 MHz, 490 MHz, 498 MHz, and 506 MHz. In principle, within the 7.56 MHz bandwidth covered by the DTMB channels opened in various regions, local State Grid low-power wireless devices should unconditionally retreat. The channel allocation for DTMB in the 470–510 MHz band is shown in Table 1-1 below.

[0007] Table 1-1

[0008]

[0009] As shown in Table 1 above, the starting frequency of the center frequency 474MHz is 470.22MHz and the ending frequency is 477.78MHz; the starting frequency of the center frequency 482MHz is 478.22MHz and the ending frequency is 485.78MHz; the starting frequency of the center frequency 490MHz is 486.22MHz and the ending frequency is 493.78MHz; the starting frequency of the center frequency 498MHz is 494.22MHz and the ending frequency is 501.78MHz; and the starting frequency of the center frequency 506MHz is 502.22MHz and the ending frequency is 509.78MHz.

[0010] The digital television service channels used vary from place to place; some areas use only one DTMB channel, while others use all five. Since the 470–510 MHz frequency band defined in the HPLC dual-mode wireless system standard completely overlaps with the DTMB frequency band, when a CCO or STA needs to acquire its corresponding channel, it first scans the aforementioned five service channels. If none of the five service channels are available, then a full channel scan is required, which takes a long time, resulting in the CCO or STA needing a considerable amount of time to acquire a usable channel.

[0011] In some regions, relevant departments with some management and coordination capabilities regarding spectrum usage have described channel selection strategies and available channels to ensure network efficiency and interoperability. In field applications, frequency scanning is first performed on these available channels. If a channel is available, an optimal channel is selected from among them. If none of the channels are available, then frequency scanning is performed on all channels. Since the bandwidth occupied by wireless channels is defined as 200kHz, 500kHz, or 1000kHz respectively, the total number of sub-channels corresponding to the frequency range of 470–510MHz is N, as shown in Table 1-2.

[0012] Table 1-2

[0013]

[0014] The bandwidths of 200kHz, 500kHz, or 1000kHz mentioned above correspond to the selection of three communication modes (Options). Specifically, communication mode Option 1 has a bandwidth (channel spacing) of 1000kHz, with 39 available sub-channels N and an initial sub-channel center frequency of 471.0MHz, meaning 39 sub-channels with a 1000kHz channel spacing can be divided within the frequency range of 470–510MHz. Communication mode Option 2 has a bandwidth (channel spacing) of 500kHz, with 79 available sub-channels N and an initial sub-channel center frequency of 470.5MHz, meaning 79 sub-channels with a 500kHz channel spacing can be divided within the frequency range of 470–510MHz. Communication mode Option 3 has a bandwidth (channel spacing) of 200kHz, with 199 available sub-channels N and an initial sub-channel center frequency of 470.1MHz, meaning 199 sub-channels with a 200kHz channel spacing can be divided within the frequency range of 470–510MHz. Due to the large number of sub-channels, scanning each sub-channel individually takes a considerable amount of time. If the frequency is scanned one channel at a time, the wireless network access of the slave node is slow, especially when it is first accessed, it will take a long time; the connection between the meter reader and the master and slave nodes is also slow. In plug-and-play situations, the time for the meter reader to connect to and read the master and slave nodes is too long.

[0015] Furthermore, as shown in Table 1-2, communication modes Option 2 and Option 3 exhibit partial overlap in their center frequencies across the entire 40MHz bandwidth. One method for designating the STA wireless channel in an HPLC dual-mode system involves first accessing the system via a wired connection using the HPLC to obtain the sub-channel number provided by the BECON frame information. If this sub-channel number is unique to Option 2 or Option 3, the communication mode Option of the accessed wireless channel can be directly determined. If the sub-channel number provided by the BECON frame is shared by Option 2 or Option 3, the STA cannot directly obtain the communication mode Option of the wireless channel.

[0016] The commonly used decision communication mode, Option, involves attempting to decode Option2 and Option3 sequentially until the correct decoding is achieved. Alternatively, it can be determined directly by the range of the frequency domain signal; Option2 has a bandwidth of 500kHz, while Option3 has a bandwidth of 200kHz. Method one is slow, and decoding success is easily affected by SNR (Signal NR). Method two, at low SNR levels, especially below 0dB, makes it difficult to determine the bandwidth based on the power of the frequency domain signal. Summary of the Invention

[0017] The purpose of this invention is to provide a frequency sweeping method, detection method, and apparatus based on an HPLC dual-mode wireless system. Firstly, it addresses the problem that when the number of sub-channels is large, sweeping the frequency of each sub-channel individually causes the CCO or STA to take a long time to acquire a usable channel. Secondly, it addresses the problem of low efficiency in determining the communication mode Option for overlapping channels.

[0018] To achieve the above objectives, the present invention includes:

[0019] The present invention provides a frequency sweeping method based on an HPLC dual-mode wireless system, comprising the following steps:

[0020] S1: Determine that the current broadband channel environment is a DTMB channel environment;

[0021] S2: Determine the list of sub-channel numbers within the DTMB channel interval based on the DTMB channel activation status;

[0022] S3: Perform frequency sweeping on the sub-channel number list within the DTMB channel interval in sequence. When an accessible sub-channel is detected, the frequency sweep ends; otherwise, proceed to S4.

[0023] S4: Determine the list of center frequency points of the DTMB channel based on the DTMB channel opening status;

[0024] S5: Perform frequency sweeping on the list of center frequency points of the DTMB channel in sequence. When an accessible sub-channel is detected, the frequency sweeping ends.

[0025] This invention improves the frequency sweeping efficiency to a certain extent by first sweeping the list of sub-channel numbers within the DTMB interval and then sweeping the list of center frequency points of the DTMB channel, thereby shortening the time required for the CCO or STA to obtain a usable channel.

[0026] Furthermore, the list of subchannel numbers within the DTMB channel interval and the list of center frequency points of the DTMB channel include subchannel numbers that transmit HPLC wireless signals to the CCO and / or STA; the method for detecting accessible subchannels in S3 includes determining whether the subchannel containing the HPLC wireless signal is occupied by performing STF autocorrelation calculation on the HPLC wireless signal received by the CCO and / or STA.

[0027] In S3 of this invention, an accessible subchannel is detected by determining whether the subchannel is occupied. This invention determines whether the subchannel of the subchannel number where the HPLC wireless signal is located is occupied by performing STF autocorrelation operation on the HPLC wireless signal received by CCO and / or STA, thereby obtaining the accessible subchannel simply and reliably.

[0028] Furthermore, the method for determining whether a subchannel containing an HPLC wireless signal is occupied includes: within a first set detection time T1, if no STF signal is detected on any subchannel number, the subchannel is considered unoccupied; within the first set detection time T1, if an STF signal is detected on any subchannel number, CFO estimation and decoding are performed on the STF signal; if network packet information is found in the signal, the subchannel is considered occupied; if decoding fails or the signal does not contain network packet information, the subchannel is considered unoccupied.

[0029] This invention detects whether a subchannel number contains an STF signal. If no STF signal is detected on the subchannel number, the subchannel is considered unoccupied. Otherwise, CFO estimation and decoding are performed on the STF signal on the subchannel number, yielding one of two results: first, if the signal contains network packet information, the subchannel is considered occupied; second, if decoding fails or the signal does not contain network packet information, the subchannel is considered unoccupied. The method provided by this invention for determining whether a subchannel containing an HPLC wireless signal is occupied provides a reliable and effective basis for identifying accessible subchannels.

[0030] Furthermore, the method for detecting accessible sub-channel numbers in S3 also includes determining whether the sub-channel accessed by the CCO is available. The method for determining whether the sub-channel accessed by the CCO is available includes: if the sub-channel is occupied, then the sub-channel is considered unavailable; if decoding fails or the signal is parsed and does not contain network packet information, then the sub-channel is considered unoccupied; calculate the RSSI value reflecting the channel quality of the sub-channel; if the RSSI value exceeds the power threshold, then the sub-channel is considered unavailable; if the RSSI value does not exceed the power threshold, then the sub-channel is considered available; if no STF signal is detected on the sub-channel number, then the sub-channel is considered unoccupied and available.

[0031] The CCO of this invention transmits data after accessing a sub-channel, thus requiring certain channel quality. By comparing a power threshold with the RSSI value, which reflects the channel quality of the sub-channel, channels with high noise floor (i.e., RSSI value exceeding the power threshold) are filtered out, failing to meet the quality requirements for CCO access. Channels that meet the channel quality requirements (low noise floor, i.e., RSSI value not exceeding the power threshold) are selected as accessible sub-channels, improving the channel quality of the sub-channels accessed by the CCO and ensuring high-quality and efficient frequency sweeping.

[0032] Furthermore, the available sub-channels are included in the list of optional access sub-channel numbers. The RSSI values ​​of the sub-channels for which no STF signal was detected are calculated, and the sub-channels are sorted according to their RSSI values ​​in the list of optional access sub-channel numbers to obtain the channel quality ranking of the sub-channels in the list of optional access sub-channel numbers, which is then selected for access.

[0033] This invention includes available sub-channels in a list of optional access sub-channel numbers, calculates the RSSI value of each sub-channel in the list of optional access sub-channel numbers, and sorts the sub-channels according to their RSSI values ​​to obtain a ranking of the channel quality of the sub-channels in the list of optional access sub-channel numbers, which is then selected during access and helps to improve the channel quality of the selected sub-channels.

[0034] Furthermore, the method for detecting an accessible sub-channel number in S3 also includes determining whether the channel accessed by the STA is available. The method for determining whether the channel accessed by the STA is available includes: if the sub-channel is not occupied, then the sub-channel is considered unavailable; if the sub-channel is occupied, then the sub-channel is considered available.

[0035] In this invention, the STA receives data after accessing a subchannel. When the subchannel is not occupied, there is no data being transmitted to the STA in the subchannel, so it is unusable; when the subchannel is occupied, there is data being transmitted to the STA in the subchannel, so it is usable.

[0036] Furthermore, the available sub-channels are included in the list of optional access sub-channel numbers. The RSSI and SNR values ​​of the sub-channels in the list of optional access sub-channel numbers are calculated and sorted according to the size of the RSSI and SNR values. This yields the ranking of the channel quality of the sub-channels in the list of optional access sub-channel numbers, which is then selected for access.

[0037] This invention includes available sub-channels in a list of optional access sub-channel numbers, calculates the RSSI and SNR values ​​of the sub-channels in the list of optional access sub-channel numbers, and sorts them according to the size of the RSSI and SNR values ​​to obtain a ranking of the channel quality of the sub-channels in the list of optional access sub-channel numbers, which is used for selection during access and helps to improve the channel quality of the selected sub-channels.

[0038] This invention can add the sub-channels available at the Central Coordinator (CCO) and the sub-channels available at the Station (STA) to their respective memory's list of accessible sub-channels, making it easier for the CCO and STA to access their respective available channels.

[0039] The receiving device processes the received wireless signal using the Received Signal Strength Indication (RSSI). RSSI is a metric that measures the strength of the wireless signal between the transmitting and receiving devices. SNR, or Signal-to-Noise Ratio, is the ratio of the useful signal to the noise signal in a wireless signal, measured in dB. Since SNR is the ratio of the useful signal strength to the noise signal strength, it can be used to determine whether the wireless signal is weak. A preset condition for a wireless signal to meet this condition may be that its SNR is less than a preset SNR threshold. If the SNR is less than the threshold, the wireless signal is considered weak and its RSSI needs to be corrected. Conversely, if the SNR is greater than the threshold, the signal is not weak and its RSSI does not need to be corrected.

[0040] A communication mode detection method based on an HPLC dual-mode wireless system includes dividing a sub-channel number list within a DTMB channel interval and a center frequency point list of the DTMB channel into multiple communication modes; scanning the frequency according to the sub-channel number list within the DTMB channel interval and the center frequency point list of the DTMB channel to obtain a list of optional access sub-channel numbers; each sub-channel number in the list of optional access sub-channel numbers has a corresponding communication mode; when there are overlapping sub-channel numbers under any two or more communication modes in the list of optional access sub-channel numbers, the communication mode of the overlapping sub-channel number is determined according to the channel correlation characteristics of the LTF, thereby determining the sub-channel to which the overlapping sub-channel number belongs.

[0041] This invention determines the communication mode of overlapping sub-channel numbers based on the channel correlation of LTF, thereby identifying the sub-channel to which the overlapping sub-channel number belongs. This method is unaffected by low SNR in determining the channel autocorrelation results and can efficiently and accurately obtain the communication mode of overlapping sub-channel numbers.

[0042] Furthermore, the sub-channel to which the overlapping sub-channel number belongs is determined by the following method: obtaining the LTF frequency domain data of each overlapping sub-channel number, performing channel estimation processing on the LTF frequency domain data for the corresponding communication mode to obtain the channel estimation result for each communication mode, and denoting the channel estimation result for each communication mode as LTF-H1, LTF-H2, ..., LTF-Hn respectively; performing autocorrelation processing on the above channel estimation results, the calculation formula is as follows:

[0043]

[0044] The length of the channel estimation result for each communication mode is N. Preferably, for communication mode 1, N = 10⁵, for communication mode 2, N = 6³, and for communication mode 3, N = 2¹. The autocorrelation operation result corresponding to the channel estimation result for each communication mode is denoted as Acorr-Hn. The magnitudes of Acorr-Hn for overlapping sub-channel numbers are compared, and the communication mode corresponding to the Acorr-Hn with the larger magnitude is considered to be the communication mode for that overlapping sub-channel number.

[0045] The method provided by this invention for obtaining the sub-channel to which the overlapping sub-channel number belongs does not affect the autocorrelation operation results under low SNR and can obtain the communication mode of the overlapping sub-channel number accurately.

[0046] Furthermore, after detecting the STF signal, the frame header is obtained, and the OFDM symbol of the LTF is obtained according to the wireless communication protocol. The OFDM symbol is then subjected to FFT to obtain the LTF frequency domain data.

[0047] An apparatus based on an HPLC dual-mode wireless system includes a processor that executes instructions to implement the above-described method.

[0048] This invention improves frequency scanning efficiency to some extent by first scanning the list of sub-channel numbers within the DTMB interval and then scanning the list of center frequency points of the DTMB channels, thereby shortening the time required for the CCO or STA to acquire a usable channel. This invention determines the communication mode of overlapping sub-channel numbers based on the channel correlation of the LTF, thus identifying the sub-channel to which the overlapping sub-channel number belongs. This method is unaffected by low SNR in determining the channel autocorrelation results and can efficiently and accurately obtain the communication mode of overlapping sub-channel numbers. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the physical layer frame structure of an existing HPLC dual-mode wireless system;

[0050] Figure 2 This is a schematic diagram of the frequency sweep process of the HPLC dual-mode wireless system under the DTMB channel environment of the present invention;

[0051] Figure 3 This is a schematic diagram of the frequency sweeping process of CCO within the DTMB channel interval of the present invention;

[0052] Figure 4 This is a schematic diagram of the frequency sweeping process of CCO on the sub-channel number list of DTMB channel intervals in this invention;

[0053] Figure 5 This is a schematic diagram of the frequency sweeping process of STA within the DTMB channel interval of the present invention;

[0054] Figure 6 This is a schematic diagram of the frequency sweeping process of STA on the sub-channel number list within the DTMB channel interval of the present invention;

[0055] Figure 7 This is a schematic diagram of the communication mode detection process for overlapping sub-channel numbers under multiple communication modes according to the present invention;

[0056] Figure 8 This is a schematic diagram of the frame structure of STF and LTF of the present invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0058] Example 1 of a frequency sweeping method based on an HPLC dual-mode wireless system:

[0059] A frequency sweeping method based on an HPLC dual-mode wireless system, such as Figure 2 As shown, it includes the following steps:

[0060] S1: Determine that the current broadband channel environment is a DTMB channel environment;

[0061] S2: Determine the list of sub-channel numbers within the DTMB channel interval (gap) based on the DTMB channel activation status;

[0062] S3: Perform frequency sweeping on the list of sub-channel numbers within the DTMB channel interval as shown in Table 1. When an accessible sub-channel is detected, the frequency sweeping ends; otherwise, proceed to S4.

[0063] S4: Determine the list of center frequency points of the DTMB channel based on the DTMB channel opening status;

[0064] S5: Perform frequency sweeping on the list of center frequency points of the DTMB channel in sequence. When an accessible sub-channel is detected, the frequency sweep ends; otherwise, proceed to S6.

[0065] S6: After the interval T0, execute S1 to S6 again.

[0066] This invention improves the frequency sweeping efficiency to a certain extent by first sweeping the list of sub-channel numbers within the DTMB interval and then sweeping the list of center frequency points of the DTMB channel, thereby shortening the time required for the CCO or STA to obtain a usable channel.

[0067] Table 1 shows a list of sub-channel numbers within the DTMB channel interval when all DTMB channels are open.

[0068] Table 1. List of sub-channel numbers within the DTMB channel interval (5 channels in total)

[0069]

[0070] like Figure 3 and Figure 5 As shown, firstly, it queries whether the current broadband channel environment is a DTMB channel environment. If so, it receives a channel query request, responds to the frequency sweep request under the DTMB channel environment, determines the sub-channel number list within the DTMB channel interval, and then performs the calculation within a set period [corresponding to the interval time T0 in the text (see appendix)]. Figure 2 Within the time interval T0), S1 to S6 are executed again; the sub-channel number list within the DTMB channel interval is sequentially scanned, and the available or accessible sub-channel numbers and their RSSI values ​​or calculated values ​​(SNR values ​​and RSSI values) are added to the list of optional access (accessible) sub-channels.

[0071] The subchannel number list within the DTMB channel interval and the center frequency point list of the DTMB channel include subchannel numbers that transmit HPLC wireless signals to the CCO and / or STA; the method for detecting accessible subchannels in S3 includes determining whether the subchannel containing the HPLC wireless signal is occupied by performing STF autocorrelation processing on the HPLC wireless signal received by the CCO and / or STA; wherein performing STF autocorrelation processing on the HPLC wireless signal received by the CCO and / or STA is... Figure 4 and Figure 6 Frame detection processing.

[0072] The method for determining whether a subchannel containing an HPLC wireless signal is occupied includes: if no STF signal is detected on any subchannel number within a first set detection time T1, the subchannel is considered unoccupied; if an STF signal is detected on any subchannel number within the first set detection time T1, CFO estimation and decoding are performed on the STF signal. If network packet information is found in the signal, the subchannel is considered occupied; if decoding fails or network packet information is not found in the signal, the subchannel is considered unoccupied.

[0073] The method for detecting accessible sub-channel numbers in S3 also includes determining whether the sub-channel accessed by the CCO is available. The method for determining whether the sub-channel accessed by the CCO is available includes: if the sub-channel is occupied, then the sub-channel is considered unavailable; if decoding fails or the signal is parsed and does not contain network packet information, then the sub-channel is considered unoccupied; calculate the RSSI value, which reflects the channel quality of the sub-channel; if the RSSI value exceeds the power threshold, then the sub-channel is considered unavailable; if the RSSI value does not exceed the power threshold, then the sub-channel is considered available; if no STF signal is detected on the sub-channel number, then the sub-channel is considered unoccupied and available.

[0074] The available sub-channels are added to the list of sub-channels available for access. The RSSI values ​​of the sub-channels for which no STF signal was detected are calculated. The sub-channels are then sorted according to their RSSI values ​​in the list of sub-channels available for access, thus obtaining a ranking of the channel quality of the sub-channels in the list of sub-channels available for access.

[0075] Specifically, such as Figure 4 As shown, the process includes: sequentially performing frame detection processing on the list of sub-channel numbers (or the list of center frequency points of the DTMB channel) within a set period (the first set detection time T1); determining whether a sub-channel number is available based on the RSSI value and STF signal; if available, adding the sub-channel number to the list of selectable sub-channel numbers; and determining whether the current sub-channel number is the last specified sub-channel number. If yes, the current frequency scan ends; otherwise, the frame detection processing for the next sub-channel number continues.

[0076] The STF autocorrelation operation is performed on the HPLC wireless signal received by the CCO. The corresponding judgment logic and steps include:

[0077] If no STF signal is detected on any sub-channel number within the first set detection time T1, it is determined that no HPLC wireless signal was detected, and the sub-channel number is considered available (not occupied).

[0078] If an STF signal is detected on a sub-channel number within the first set detection time T1, CFO estimation and decoding are performed. If the signal contains network packet information, it is determined that an HPLC wireless signal has been detected, and the sub-channel number is considered to be occupied (unavailable), and the process jumps to the next sub-channel number. If decoding fails or the signal does not contain network packet information, it is determined that no HPLC wireless signal has been detected, and the RSSI value of the sub-channel is calculated. If the RSSI value exceeds the power threshold, the channel is considered to have a high noise floor and is not suitable as an access channel, and the sub-channel number is considered unavailable, and the process jumps to the next sub-channel number. If the RSSI value does not exceed the power threshold, the sub-channel is considered to have a low noise floor and can be used as an access channel, and the sub-channel number is considered available. The sub-channel number and the corresponding RSSI value are recorded in the list of available access sub-channel numbers.

[0079] Determine whether the current subchannel number is the last subchannel number in the subchannel number list within the DTMB channel interval; if yes, end the current frequency sweep. If no, continue with the autocorrelation operation for the next subchannel number.

[0080] After all sub-channel numbers have been scanned, the available sub-channel numbers are sorted in ascending order of their RSSI values.

[0081] The method for detecting an accessible sub-channel number in S3 also includes determining whether the channel accessed by the STA is available. The method for determining whether the channel accessed by the STA is available includes: if the sub-channel is not occupied, then the sub-channel is considered unavailable; if the sub-channel is occupied, then the sub-channel is considered available.

[0082] The available sub-channels are added to the list of sub-channel numbers for optional access. The RSSI and SNR values ​​of the sub-channels in the list of sub-channel numbers for optional access are calculated and sorted according to the size of the RSSI and SNR values. This yields a ranking of the channel quality of the sub-channels in the list of sub-channel numbers for optional access, which is then selected during access.

[0083] This invention allows the CCO (Central Coordinator) and STA (Station) sub-channels to be added to their respective accessible sub-channel lists in their respective memories, facilitating access to their respective available channels. Alternatively, this invention can add the CCO and STA sub-channels to their respective accessible sub-channel lists within the same memory, or combine them into a single accessible sub-channel list.

[0084] Specifically, such as Figure 6As shown, the process includes: sequentially performing frame detection processing on the list of sub-channel numbers (or the list of center frequency points of the DTMB channel) within a set period (the first set detection time T1); determining whether a sub-channel number is available based on calculated values ​​(RSSI and SNR values) and the STF signal; if available, adding the sub-channel number to the list of selectable sub-channel numbers; and determining whether the current sub-channel number is the last specified sub-channel number. If yes, the current frequency sweep ends; otherwise, the frame detection processing for the next sub-channel number continues.

[0085] The STF autocorrelation operation is performed on the HPLC wireless signal received by the STA. The corresponding judgment logic and steps include:

[0086] If no STF signal is detected on any sub-channel number within the first set detection time T1, it is determined that no HPLC wireless signal has been detected, and the sub-channel number is considered to be occupied (unavailable), and the process jumps to the next sub-channel number.

[0087] If an STF signal is detected on a sub-channel number within the first set detection time T1, CFO estimation and decoding are performed. If decoding fails or the signal does not contain network packet information, the sub-channel number is considered unusable. If the signal contains network packet information, an HPLC wireless signal is detected, and the sub-channel number is considered unoccupied (usable). The RSSI and SNR values ​​of the sub-channel are calculated. The sub-channel number and its RSSI and SNR values ​​are recorded in the list of available access sub-channel numbers, and the process moves to the next sub-channel number.

[0088] Determine whether the current sub-channel number is the last specified sub-channel number. If yes, end the current frequency sweep; otherwise, continue with the frame detection processing for the next sub-channel number.

[0089] After scanning all sub-channel numbers, the detected sub-channel numbers are sorted in descending order of SNR and RSSI values ​​(SNR power and RSSI power in the figure).

[0090] The list of optional access sub-channel numbers can be the list of optional access sub-channel numbers of the CCO, the list of optional access sub-channel numbers of the STA, or the list of optional access sub-channel numbers of the CCO plus the STA.

[0091] Example 1 of a communication mode detection method based on an HPLC dual-mode wireless system:

[0092] A communication mode detection method based on an HPLC dual-mode wireless system, such as Figure 7As shown, the process includes: dividing the sub-channel number list within the DTMB channel interval and the center frequency point list of the DTMB channel into multiple communication modes; scanning the frequency based on the sub-channel number list within the DTMB channel interval and the center frequency point list of the DTMB channel to obtain a list of optional access sub-channel numbers; each sub-channel number in the list of optional access sub-channel numbers has a corresponding communication mode; when there are overlapping sub-channel numbers under any two or more communication modes in the list of optional access sub-channel numbers, the communication mode of the overlapping sub-channel number is determined based on the channel correlation characteristics of the LTF, thereby determining the sub-channel to which the overlapping sub-channel number belongs. The list of optional access sub-channel numbers is obtained through a frequency scanning method, which has been described in detail in an embodiment of a frequency scanning method based on an HPLC dual-mode wireless system and will not be repeated here.

[0093] Specifically, the LTF frequency domain data of each overlapping sub-channel number is obtained. Channel estimation processing for the corresponding communication mode is then performed on the LTF frequency domain data to obtain the channel estimation result for each communication mode. The channel estimation results for each communication mode are denoted as LTF-H1, LTF-H2, ..., LTF-Hn, respectively. Autocorrelation processing is then performed on the above channel estimation results, and the calculation formula is as follows:

[0094]

[0095] The length of the channel estimation result for each communication mode is N; the autocorrelation operation result corresponding to the channel estimation result for each communication mode is denoted as Acorr-Hn; the magnitudes of Acorr-Hn for overlapping sub-channel numbers are compared, and the communication mode corresponding to the Acorr-Hn with the larger magnitude is considered to be the communication mode for that overlapping sub-channel number; after detecting the STF signal, the physical layer frame header is obtained, and the OFDM symbol of the LTF is obtained according to the wireless communication protocol, such as... Figure 8 As shown, OFDM symbols can be further processed by FFT to obtain LTF frequency domain data.

[0096] For example, according to the communication modes Options 1-3 in Table 1, where communication mode Option 1 has no sub-channel number, channel estimation processing for communication modes Option 2 and Option 3 is performed only on the LTF frequency domain data, and the results are denoted as LTF-H2 and LTF-H3, respectively. The length of LTF-H2 is N = 53, and the length of LTF-H3 is N = 21 (both include the DC carrier channel). Autocorrelation operations are performed on LTF-H2 and LTF-H3 respectively. The calculation formula is as follows:

[0097]

[0098] The results of autocorrelation operations on LTF-H2 and LTF-H3 are denoted as Acorr-H2 and Acorr-H3, respectively.

[0099] Finally, the magnitudes of Acorr-H2 and Acorr-H3 are compared, and the option corresponding to the larger value is the detection result. This method is applicable to blind detection of multiple options.

[0100] This invention determines the communication mode of overlapping sub-channel numbers based on the channel correlation of LTF, thereby identifying the sub-channel to which the overlapping sub-channel number belongs. This method is unaffected by low SNR in determining the channel autocorrelation results and can efficiently and accurately obtain the communication mode of overlapping sub-channel numbers.

[0101] Example 1 of a device based on an HPLC dual-mode wireless system:

[0102] An apparatus based on an HPLC dual-mode wireless system includes: a processor that executes a frequency sweep method and / or a communication mode detection method. The frequency sweep method and the communication mode detection method are described in detail in the respective embodiments of the frequency sweep method and the communication mode detection method based on the HPLC dual-mode wireless system, and will not be repeated here.

Claims

1. A method for detecting a communication mode based on a HPLC dual-mode wireless system, characterized by, The method comprises: dividing a subchannel number list within a DTMB channel interval and / or a center frequency point list of a DTMB channel into multiple communication modes; obtaining a selectable access subchannel number list by sweeping according to the subchannel number list within the DTMB channel interval and / or the center frequency point list of the DTMB channel, each subchannel number in the selectable access subchannel number list has a corresponding communication mode; when there are any two or more communication modes that coincide in the selectable access subchannel number list, obtaining LTF frequency domain data of the coinciding subchannel numbers, respectively performing channel estimation processing of the LTF frequency domain data according to the corresponding communication modes to obtain channel estimation results of each communication mode, and recording each channel estimation result of each communication mode as LTF-H1, LTF-H2, …, LTF-Hn, respectively; performing autocorrelation operation processing on the above channel estimation results, and the calculation formula is as follows: wherein the length corresponding to each channel estimation result of each communication mode is N; the autocorrelation operation processing result corresponding to each channel estimation result of each communication mode is recorded as Acorr-Hn, respectively; and the modulus of Acorr-Hn of the coinciding subchannel numbers is compared, and it is considered that the communication mode corresponding to the Acorr-Hn with a larger modulus is the communication mode of the coinciding subchannel number.

2. The method of claim 1, wherein the HPLC dual-mode wireless system-based communication mode detection method is characterized by, After detecting the STF signal, a frame header is obtained, and an OFDM symbol of the LTF is obtained according to a wireless communication protocol, and the LTF frequency domain data is obtained after FFT of the OFDM symbol.

3. An apparatus based on HPLC dual-mode wireless system, characterized by, The method comprises a processor, and the processor executes instructions for implementing the method according to claim 1 or 2.

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