A fast channel detection method and device suitable for TDMA system

Abstract

The application belongs to the technical field of wireless communication, and relates to a fast channel detection method and device suitable for a TDMA system. The method comprises the following steps: acquiring a channel detection enabling signal and a to-be-detected frequency point which needs to be detected at present, the signal being sent by a system according to a current network node state; judging whether a signal is synchronized within a set time length at the front part of a current receiving time slot; if the signal is not synchronized, directly performing channel detection on the to-be-detected frequency point in the current receiving time slot; if the signal is synchronized, calculating a receiving frame length according to received control information, so as to obtain a residual channel detection time of the current receiving time slot, and performing channel detection on the to-be-detected frequency point within the residual channel detection time; and after the channel detection is completed, reporting the detection frequency point and a corresponding energy value, so as to supply the system for planning of a next round of channel detection frequency. The scheme of the application can fully utilize time slot resources, can reflect a channel state in real time, and can improve the reliability of wireless transmission.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology. More specifically, this invention relates to a fast channel detection method and apparatus suitable for TDMA systems. Background Technology

[0002] In Time Division Multiple Access (TDMA) communication systems, time resources are typically allocated and managed in units of time slots. To achieve orderly networking and efficient communication among multiple nodes in the network, the system usually divides time slot resources into different functional time slots according to design and service requirements. These include transmit time slots for sending data frames, receive time slots for receiving data frames, and channel detection time slots specifically for detecting the channel environment. The main purpose of channel detection is to detect the background noise or air interface energy level of a specified channel, thereby determining whether the channel is currently subject to external interference and deciding whether the channel is suitable for subsequent data transmission or reception tasks.

[0003] To perform channel detection in existing TDMA systems, the standard procedure is typically as follows: the system allocates and reserves a dedicated channel detection time slot on the timeline. For example... Figure 1 As shown, after entering the channel detection reservation time slot, the node receives the frequency parameters to be detected issued or preset by the system, and starts the channel detection operation (such as switching frequencies, receiving signal energy, calculating air interface RSSI, calculating average and maximum values, etc.). After the channel detection is completed, the node reports the energy values ​​calculated for each frequency to the system side through the DMA channel as a decision reference for the system to perform channel switching or resource scheduling.

[0004] However, the existing channel detection methods described above have the following significant drawbacks in practical network applications: 1. Significant waste of time slot resources: In TDMA systems, time slot resources are extremely valuable and limited. Allocating and reserving dedicated time slots solely for channel detection directly encroaches on time slots used for actual data service transmission, reducing the overall throughput and time slot resource utilization of the communication system.

[0005] 2. Delayed response of detection results and inability to reflect channel status in real time: The specially reserved channel detection time slot and the actual data transmission or reception task time slot belong to completely different time ranges on the time axis. Because wireless channel interference is typically sudden, instantaneous, and time-varying, the channel status measured within the dedicated detection time slot may have changed drastically by the time the service transmission time slot actually begins. This time discrepancy means that the detection results cannot accurately reflect the true channel status of the current communication, easily leading to invalid channel decisions based on these results.

[0006] Therefore, the urgent technical problems to be solved are the waste of time slot resources for channel detection by reserving channel detection time slots separately, and the difficulty in reflecting the current channel status in TDMA systems. Summary of the Invention

[0007] To address the aforementioned technical problems with existing channel detection methods, the present invention provides solutions in the following aspects.

[0008] In a first aspect, the present invention proposes a fast channel detection method suitable for TDMA systems, comprising: Step S1: In the receiving time slot, acquiring the channel detection enable signal sent by the system according to the current network node status and the frequency point to be detected that needs to be detected for channel detection; Step S2: Determining whether a signal is synchronized within a predetermined time period before the current receiving time slot; Step S3: If a signal is not synchronized, directly performing channel detection on the frequency point to be detected within the current receiving time slot; Step S4: If a signal is synchronized, calculating the received frame length according to the received control information to obtain the remaining channel detection time of the current receiving time slot, and performing channel detection on the frequency point to be detected within the remaining channel detection time; the control information is the frame header control field in the current wireless data frame synchronized by the communication node; Step S5: After the channel detection is completed, reporting the detected frequency point and the corresponding energy value for the system to plan the channel detection frequency for the next round.

[0009] According to the scheme of this invention, channel detection is performed by making full use of the idle state and remaining time of the receive time slot, breaking the limitation of traditional TDMA systems that must separately allocate and reserve dedicated detection time slots, thus significantly saving precious time slot resources. Simultaneously, since the detection and the current receive task are in the same time slot or very close to each other, the detection results can quickly and in real-time reflect the current channel state, providing a highly timely prior reference for subsequent task decisions. Furthermore, the mechanism of intelligently parsing the frame header control field to dynamically squeeze out remaining time ensures that detection can still be completed when there are signal conflicts, improving the fault tolerance and flexibility of the detection.

[0010] Furthermore, in step S2, the pre-set duration is the length of the first quarter of the current receiving time slot.

[0011] According to the present invention, the decision window is limited to the first quarter of the time slot length, leaving ample time for subsequent calculations and channel detection, up to three-quarters of the time slot length. Since channel detection takes a very short time relative to the data frame length, this 1 / 4 decision and 3 / 4 detection window division ensures that even when synchronized to the signal, the remaining time is sufficient to support high-precision channel detection, achieving refined and maximized utilization of time slot resources.

[0012] Furthermore, if the signal is synchronized within the first quarter of the time slot length, then the remaining channel detection time within the latter three-quarters of the time slot length is used for channel detection.

[0013] Furthermore, in step S1, before obtaining the channel detection enable signal, the method further includes: performing frequency planning on the TDMA system, dividing the frequency bands available for communication into N channel numbers, wherein the frequency point to be detected is selected from the N channel numbers.

[0014] According to the scheme of the present invention, by performing scientific frequency allocation and channel number mapping globally, the distribution and management of the frequency points to be detected have a standardized discrete structure, which reduces the number of parameters of system interaction and is conducive to realizing fast polling scheduling of multiple channels.

[0015] Furthermore, the channel detection of the frequency to be detected includes: switching to the frequency to be detected, receiving signal energy, and calculating the received signal strength index (RSSI).

[0016] Furthermore, the formula for calculating the received signal strength index (RSSI) is: RSSI = rx gain +rssi index +lna data +cst data Among them, rx gain This represents the chip gain value, rssi index The index of the decibel value corresponding to the average energy of the received IQ data, lna data cst is the value of the low-noise amplifier (LNA). data This is the calibration value.

[0017] According to the present invention, a precise digital mathematical model for calculating the Received Signal Strength Indication (RSSI) over the air interface is provided. By performing full-path fusion compensation of chip gain, IQ data decibel value, LNA value, and calibration value, the influence of dynamic fluctuations in hardware gain of the front-end hardware on energy assessment is eliminated, making the final calculated air interface energy value closer to the real physical environment and greatly improving the accuracy of channel detection.

[0018] Furthermore, in step S5, the reporting of the detection frequency point and the corresponding energy value includes: reporting the frequency point to be detected and the corresponding average and maximum RSSI values ​​through the direct memory access (DMA) channel.

[0019] According to the present invention, a direct memory access channel is used for data reporting, enabling channel detection results to bypass the CPU and be directly transmitted to the system storage area. This significantly reduces the real-time interrupt overhead of the communication node's CPU, ensures extremely high real-time performance of detection data reporting, and meets the system-level requirements for rapid detection and rapid reporting.

[0020] Furthermore, after reporting the detection frequency and corresponding energy value, the method further includes: analyzing the reported detection frequency and corresponding energy value to obtain the energy distribution of each channel frequency, thereby determining the interference level of each channel.

[0021] Furthermore, after analyzing the reported detection frequency points and corresponding energy values, the method further includes using the interference level as prior information for selecting the transmission and reception channels; and the planning of the next round of channel detection frequency is as follows: based on the pre-defined channel numbers, the channel detection is performed by sequentially polling as the frequency points to be detected in the next round.

[0022] According to the scheme of the present invention, intelligent closed-loop iteration of detection and planning is realized. By statistically analyzing the reported energy values, the energy distribution spectrum of the current communication environment in each frequency band can be drawn, and the interference level of each channel can be accurately determined, providing extremely reliable prior information for the avoidance or optimal selection of subsequent transmission and reception channels; at the same time, the next round of detection is planned through a sequential polling mechanism, ensuring the completeness and balance of the full-band scanning.

[0023] In a second aspect, the present invention also provides a fast channel detection device suitable for TDMA systems, comprising: a processor; and a memory storing computer program instructions, wherein when the processor executes the computer program instructions, it implements a fast channel detection method suitable for TDMA systems as described in one or more of the preceding embodiments.

[0024] The beneficial effects of this invention are as follows: This invention makes full use of the receiving time slot resources. Based on the characteristics of multi-node networking, it utilizes the idle state of the receiving time slot for channel detection, which not only saves time slot resources and ensures the real-time performance of channel detection, but also quickly reflects the channel status, providing a decision-making reference for subsequent tasks. Attached Figure Description

[0025] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein: Figure 1 This is a schematic diagram illustrating the principle of existing channel detection methods; Figure 2 This is a flowchart illustrating a fast channel detection method according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the execution steps of a channel detection method applying an embodiment of the present invention; Figure 4This is a schematic diagram illustrating the composition of a fast channel detection device according to an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Based on the characteristics of multi-node networks, only a limited number of nodes are receiving signals, while the rest are in an idle receiving state. Furthermore, the signal reception time of receiving nodes may be short, leaving remaining time in the receiving time slot for channel detection. Therefore, this invention fully utilizes receiving time slot resources, leveraging the idle state of these slots for channel detection. This not only saves time slot resources but also quickly reflects the channel status, providing a decision-making reference for subsequent tasks.

[0028] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] Figure 2 This is a flowchart illustrating a fast channel detection method according to an embodiment of the present invention.

[0030] This embodiment provides a fast channel detection method suitable for TDMA systems, the main implementing entity of which is the wireless communication node (such as a mobile terminal, gateway, base station, or network node) in the TDMA communication system. Figure 2 As shown, the main steps include: Step S1: In the receiving time slot, obtain the channel detection enable signal sent by the system according to the current network node status and the frequency point to be detected that needs to be detected for channel detection.

[0031] Furthermore, before acquiring the channel detection enable signal, the process includes frequency planning for the TDMA system, dividing the available frequency bands for communication into N channel numbers. The frequency to be detected is selected from these N channel numbers.

[0032] In some embodiments, the TDMA system performs frequency planning for the channel, dividing the frequency band available for communication into N channel numbers, F0, F1, F2, F3, ..., FN-1. During the receive time slot, the system sends a channel detection command based on the current network node status. If channel detection is performed, it also sends parameters such as the frequency points that need to be detected (e.g., F0, F1).

[0033] Step S2: Determine whether a signal has been synchronized within the first quarter of the current receiving time slot. This first quarter of the current receiving time slot is used as a decision window to determine whether channel detection can be performed. If a signal is synchronized within the first quarter of the time slot, channel detection is performed using the remaining channel detection time in the last three-quarters of the time slot.

[0034] It should be noted that the setting of the first quarter of the time slot is only illustrative and not restrictive. Those skilled in the art can set other durations according to actual needs, such as the first fifth of the time slot, or a fixed duration.

[0035] Step S3: If no signal is synchronized, channel detection is performed directly on the frequency point to be detected within the current receiving time slot. No signal synchronization indicates that the current channel is idle. In this case, there is no need to wait for the time slot to end; the channel detection task can be performed directly, effectively improving the efficiency and flexibility of channel detection.

[0036] Step S4: If a synchronization signal is obtained, the received frame length is calculated based on the received control information to obtain the remaining channel detection time of the current receiving time slot, and channel detection is performed on the frequency point to be detected within the remaining channel detection time.

[0037] When a synchronization signal is received, it indicates that a wireless data frame has arrived. At this point, it is necessary to wait for the current data frame to complete its transmission before performing channel detection. Based on this, it is necessary to calculate the remaining time slots available for channel detection using the frame header control field (i.e., control information) in the currently received wireless data frame.

[0038] The control information is the frame header control field in the current radio data frame synchronized by the communication node. Specifically, it may include a frame length indicator, data packet length information, or control signaling indicating the length of the current transmission frame. The communication node obtains the number of bytes or the time domain length of the current transmission frame by parsing the frame header control field, thereby calculating the exact duration required for the data frame in the current reception time slot. Then, by subtracting the exact duration from the total time slot duration, the remaining time available for channel detection in the latter half of the time slot is calculated.

[0039] In some embodiments, channel detection of the frequency to be detected includes: switching to the frequency to be detected, receiving signal energy, and calculating the Received Signal Strength Indicator (RSSI). Specifically, the formula for calculating the RSSI is as follows: RSSI=rx gain +rssi index +lna data +cst data ; Among them, rxgain This represents the chip gain value, rssi index The index of the decibel value corresponding to the average energy of the received IQ data, lna data cst is the value of the low-noise amplifier (LNA). data This is the calibration value.

[0040] Step S5: After the channel detection is completed, report the detection frequency and the corresponding energy value so that the system can plan the channel detection frequency for the next round.

[0041] To reduce the real-time interrupt overhead of the communication node's CPU and ensure high real-time performance of the reported detection data, the reported detection frequency and corresponding energy value include the frequency to be detected and the corresponding average and maximum RSSI values ​​reported through the Direct Memory Access (DMA) channel.

[0042] Furthermore, after reporting the detection frequency points and corresponding energy values, the method also includes analyzing the reported detection frequency points and corresponding energy values ​​to obtain the energy distribution of each channel frequency, thereby determining the degree of interference of each channel.

[0043] Furthermore, after analyzing the reported detection frequency points and corresponding energy values, the method also includes using the degree of interference as prior information for selecting the transmission and reception channels.

[0044] In some embodiments, the planning of the frequency for the next round of channel detection is as follows: based on the pre-defined channel numbers, the channels are sequentially polled as the frequency points to be detected in the next round for channel detection.

[0045] The above is a brief description of the solution of the present invention. The channel detection method of the present invention will be described in detail below in conjunction with a specific application process.

[0046] 1. Triggering and determination of dynamic channel detection.

[0047] In a TDMA system, time resources are divided into different time segments such as transmit time slots and receive time slots. For example... Figure 2 As shown, this embodiment completes the channel detection task by multiplexing the receive time slots.

[0048] After entering the current receiving time slot, the communication node first performs the following preparation and determination process: Step S101: Obtain the channel detection enable signal sent by the system based on the current network node status, as well as the parameters of the frequency points to be detected (e.g., known channel frequencies F0, F1, etc. planned by the system). In a multi-node network environment, typically only a limited number of nodes are in actual receiving state, while the remaining nodes are in idle receiving state. The system dynamically sends enable signals based on this status.

[0049] Step S102: After acquiring the enable signal, the communication node does not blindly start detection, but first starts a time window determination mechanism to determine whether the signal has been synchronized within the set time period before the current receiving time slot.

[0050] To ensure accurate judgment and allow sufficient time for subsequent actions, in this embodiment, the pre-set duration is preferably the first quarter (1 / 4) of the current receiving time slot. The communication node detects whether it has successfully captured the preamble or triggered a synchronization interrupt within this 1 / 4 time slot through its baseband physical layer.

[0051] 2. Dual-path adaptive detection mechanism.

[0052] Based on the determination result of step S102, the communication node dynamically selects two mutually exclusive fast detection paths: Path 1: Direct detection when there is no signal: If no signal is synchronized within the first quarter of the time slot, it means that there is no wireless data transmission for this node in the current receiving time slot, and the time slot is completely idle. At this time, the communication node does not need to wait for the time slot to end, and can directly perform channel detection on the frequency point to be detected in the current receiving time slot (that is, perform multi-frequency scanning using the remaining time in the time slot).

[0053] Path 2: Detecting remaining time during signal conflict: If signal synchronization is successfully achieved within the first quarter of the time slot, it indicates that a wireless data frame has arrived. At this point, the communication node uses the frame header control field (i.e., control information) of the currently received wireless data frame to perform online real-time calculations: (1) The node parses the control field in the header of the data frame, extracts the frame length indicator or modulation code and byte number information, and calculates the actual communication frame length T of the current data frame. frame .

[0054] (2) Given that the total duration of the current receiving time slot is T slot The node uses the formula: Remaining channel detection time = T slot -T frame This allows for the precise determination of the remaining channel detection time exposed at the end of the receive time slot after the current data frame has been transmitted.

[0055] (3) Subsequently, after the data frame is received, the communication node immediately and seamlessly switches to perform channel detection on the frequency point to be detected within the remaining channel detection time. Since the channel detection time is relatively short compared to the frame length, after deducting the first 1 / 4 time slot and the actual data frame length, as long as there is blank space at the end of the time slot, the remaining time within the last 3 / 4 time slot is sufficient to support the completion of the channel detection task.

[0056] 3. Accurate calculation and reporting of air interface energy values.

[0057] When performing channel detection in any of the above paths, the radio frequency front-end of the communication node quickly switches to the frequency to be detected and receives air interface signal energy.

[0058] To accurately and objectively eliminate the absolute error caused by different hardware amplification gains, this embodiment uses the following normalized calculation formula to calculate the received signal strength index (RSSI): RSSI=rx gain +rssi index +lna data +cst data ; Among them, rx gain This represents the chip gain value, rssi index The index of the decibel value corresponding to the average energy of the received IQ data, lna data cst is the value of the low-noise amplifier (LNA). data This is the calibration value.

[0059] In this formula, the RSSI unit on the left side of the equal sign is decibel-milliwatt (dBm). rx gain This refers to the internal amplifier gain of the current wireless chip, expressed in decibels (dB); rssi index This is the dB index corresponding to the average energy of the received IQ data demodulated from the baseband; it is itself a dB value obtained after logarithmic calculation; lna data cst represents the stepped or cascaded gain of the low-noise amplifier (LNA) at the radio frequency front end, in decibels (dB). data The full-band calibration compensation value of the RF path is pre-written into the memory, in decibels (dB).

[0060] After calculating the RSSI of each frequency point to be detected, the communication node uses the direct memory access (DMA) channel to directly transfer and report the detection frequency point number, the calculated average RSSI value, and the maximum RSSI value to the system side, thereby avoiding the occupation and consumption of the node's CPU operation cycle.

[0061] 4. Closed-loop analysis and polling planning.

[0062] After receiving data such as ((F0, RSSI0), (F1, RSSI1)) reported by the communication nodes, the system enters the closed-loop planning process: (1) Channel interference analysis: The system collects the energy values ​​corresponding to each frequency and performs statistical analysis in the time and frequency domains to obtain the energy distribution map of each frequency of the channel. This allows for a precise understanding of the severity of interference from external noise or other communication systems to each channel. This result serves as crucial prior information for the subsequent selection of transmission and reception channel numbers by the system.

[0063] (2) Next round detection planning: For the next round of time slots, the system uses a polling mechanism to perform dynamic planning based on the N channel numbers that have been allocated. For example, if F0 and F1 are detected in this round, and they are severely interfered with, the next round of planning will prioritize polling F2 and F3, thereby realizing dynamic adaptive tracking of channel quality across the entire network.

[0064] This invention proposes real-time channel detection during the idle state of the receive time slot, directly reusing the receive time slot resources of the TDMA system. Utilizing the characteristic that some nodes in a multi-node network are idle or have short receive durations, detection is completed within the remaining time of the receive time slot, significantly improving time slot utilization. A "first 1 / 4 time slot length" window determination mechanism ensures the flexibility and high fault tolerance of the detection. Furthermore, this invention provides a specific RSSI back-calculation formula (combining chip gain, IQ data, LNA value, and calibration value), and uses the reported energy value distribution as prior information to provide a reference for transmit / receive channel selection, while also guiding the polling planning of the channel detection frequency in the next round. This forms a closed loop of "detection-analysis-planning-re-detection," effectively improving the reliability of the wireless transmission process.

[0065] Figure 4 This is a schematic diagram illustrating the composition of a fast channel detection device according to an embodiment of the present invention.

[0066] This invention also provides a fast channel detection device suitable for TDMA systems. For example... Figure 4 As shown, the device includes a processor and a memory, the memory storing computer program instructions, which, when executed by the processor, implement the fast channel detection method for TDMA systems described above.

[0067] The device also includes other components well known to those skilled in the art, such as communication buses and communication interfaces, the settings and functions of which are known in the art and will not be described in detail here.

[0068] While this specification has shown and described numerous embodiments of the invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of this invention.

Claims

1. A fast channel detection method suitable for TDMA systems, characterized in that, include: Step S1: In the receiving time slot, obtain the channel detection enable signal sent by the system according to the current network node status and the frequency point to be detected that needs to be detected for channel detection. Step S2: Determine whether a signal has been synchronized within the pre-set time period of the current receiving time slot; Step S3: If no signal is synchronized, channel detection is performed directly on the frequency point to be detected within the current receiving time slot; Step S4: If a signal is synchronized, calculate the received frame length based on the received control information to obtain the remaining channel detection time of the current receiving time slot, and perform channel detection on the frequency point to be detected within the remaining channel detection time; the control information is the frame header control field in the current wireless data frame synchronized by the communication node. Step S5: After the channel detection is completed, report the detection frequency and the corresponding energy value so that the system can plan the channel detection frequency for the next round.

2. The fast channel detection method for TDMA systems according to claim 1, characterized in that, In step S2, the pre-set duration is the length of the first quarter of the current receiving time slot.

3. The fast channel detection method for TDMA systems according to claim 2, characterized in that, If the signal is synchronized within the first quarter of the time slot, then the remaining channel detection time within the second three-quarters of the time slot is used for channel detection.

4. The fast channel detection method for TDMA systems according to claim 1, characterized in that, In step S1, before obtaining the channel detection enable signal, the method further includes: Frequency planning is performed on the TDMA system, dividing the frequency band available for communication into N channel numbers, and the frequency point to be detected is selected from the N channel numbers.

5. The fast channel detection method for TDMA systems according to claim 1, characterized in that, The channel detection of the frequency point to be detected includes: Switch to the frequency to be detected, receive the signal energy and calculate the over-the-air received signal strength indicator (RSSI).

6. The fast channel detection method for TDMA systems according to claim 5, characterized in that, The formula for calculating the received signal strength index (RSSI) over the air interface is as follows: RSSI=rx gain +rssi index +lna data +cst data ; Among them, rx gain This represents the chip gain value, rssi index The index of the decibel value corresponding to the average energy of the received IQ data, lna data cst is the value of the low-noise amplifier (LNA). data This is the calibration value.

7. The fast channel detection method for TDMA systems according to claim 5, characterized in that, In step S5, the reported detection frequency point and corresponding energy value include: The frequency point to be detected, along with the corresponding average and maximum RSSI values, are reported via the Direct Memory Access (DMA) channel.

8. The fast channel detection method for TDMA systems according to claim 1, characterized in that, Following the reporting of the detection frequency and corresponding energy value, the following is also included: By analyzing the reported detection frequencies and corresponding energy values, the energy distribution of each channel frequency is obtained, thereby determining the degree of interference to each channel.

9. The fast channel detection method for TDMA systems according to claim 8, characterized in that, After analyzing the reported detection frequency points and corresponding energy values, the method further includes using the interference level as prior information for selecting the transmission and reception channels; and the planning of the next round of channel detection frequency is as follows: according to the pre-divided channel numbers, the channel detection is carried out by sequentially polling as the frequency points to be detected in the next round.

10. A fast channel detection device suitable for TDMA systems, characterized in that, include: processor; A memory storing computer program instructions, which, when executed by the processor, implement a fast channel detection method for a TDMA system as described in any one of claims 1-9.

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