Multi-parameter joint adaptive power control method for short-range wireless IoT chips

Abstract

The present invention discloses a short-distance wireless Internet of Things chip and a multi-parameter joint adaptive power control method thereof, which determines the modulation index of the short-distance wireless Internet of Things chip, determines the sensitivity threshold according to the relationship between the packet error rate and the sensitivity threshold of the receiving link under different modulation indexes, and determines the critical value of the received signal strength; if the receiving end continuously and correctly receives packets, it starts to judge whether the transmission power needs to be lowered, and judges whether the transmission power needs to be lowered according to the comprehensive judgment of the multi-parameters of the receiving end. The present invention can realize the power adaptation of wireless communication more quickly, and the response is more sensitive; it has high flexibility and a wider range of applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of short-distance wireless communications, and in particular relates to a multi-parameter joint adaptive power control method for a short-distance wireless Internet of Things chip. Background Art

[0002] In the unlicensed 2.4GHz and Sub-1GHz bands, consumer electronic devices are widely available, such as short-range wireless communication devices based on Bluetooth and other protocols. A large part of these devices are battery-powered, so they are very sensitive to power consumption. Adaptive transmit power control is a very important and effective way to reduce power consumption. This is because communication chips usually have certain reliability design indicators. Under the condition of meeting the reliability requirements of the service and having a certain amount of redundancy, excessive transmit power is undoubtedly a huge waste. Because under the condition of a certain transmit power, the received power decays exponentially with the distance. Therefore, adaptive control of the transmit power is one of the key methods to reduce chip power consumption. Taking a Bluetooth chip with good performance as an example, its sensitivity index at 1M rate is -97dBm. This means that the demodulation performance required by the protocol can still be achieved when the received signal power is -97dBm. That is, when the load of the PDU packet is 37 bytes, the bit error rate is 0.1%, and the corresponding packet error rate (PER) is 30%. If the real-time requirements of a certain type of service are not high, the packet error rate is 30%, and retransmission can meet the application requirements, then the signal power reaching the receiving end is -97dBm. If the redundancy index is 10dB, the receiving power is most suitable at -87dBm. For the transmitter, try to ensure that the power reaching the receiving end is as high as -87dBm, otherwise it will be a waste.

[0003] In order to meet the needs of different communication distances, several levels of transmission power are usually set at the transmitter of the chip. In the signal amplification link at the receiver of the chip, there is usually a dynamic range of several dozen dB. For example, Bluetooth chips generally have a dynamic range of 80 dB or more. Existing power adaptation methods generally adjust the transmission power by the accuracy of the received signal and the packet signal strength (RSSI), but the accuracy judgment takes a long time, making the response slow; and the packet signal strength threshold is also difficult to determine. Summary of the invention

[0004] Purpose of the invention: In order to solve the problem of slow adaptive response of wireless communication transmission power in the prior art, the present invention provides a multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip.

[0005] Technical solution: A multi-parameter joint adaptive power control method for a short-range wireless IoT chip, comprising the following steps:

[0006] Step 1: Determine the modulation index of the short-range wireless IoT chip, and determine the sensitivity threshold based on the relationship between the packet error rate and the sensitivity threshold of the receiving link under different modulation indices. , according to the sensitivity threshold and redundancy Determine the received signal strength threshold ;

[0007] Step 2: During the communication process, if the receiving end receives the Groups, , then the judgment of whether to reduce the transmission power is started, specifically including:

[0008] Acquisition of multiple parameters at the receiving end, including the gain adjustment of the AGC module, the overflow of the ADC module, and the signal strength of the received packet;

[0009] According to multiple parameters and the received signal strength threshold , comprehensively judge whether it is necessary to reduce the transmit power.

[0010] Furthermore, in step 2, the method for comprehensively judging whether it is necessary to reduce the transmission power includes:

[0011] If the AGC module adjusts the gain downward because the monitoring level of the LGMT module exceeds the upper limit, the transmission power is adjusted downward, and the LGMT module includes a low noise amplifier and a transconductance + mixer + transimpedance module;

[0012] If the LGMT module monitoring level does not exceed the upper limit, but the ADC module overflows, then calculate The average received signal strength of the packets , calculate the difference ,like , the transmit power is reduced; if the ADC module does not overflow, there is no need to reduce the transmit power.

[0013] Furthermore, in step 1, the method for determining the modulation index includes:

[0014] At the receiving end, multiple local reference sequences are set according to different modulation indices, which are recorded as: , is the number of modulation indices, For the The conjugate value of the transmitted signal of the address sequence portion corresponding to the modulation index, is the length of the reference sequence;

[0015] Get the received signal after frequency offset correction, denoted as ;

[0016] Calculate the correlation sequence , the modulation index of the reference sequence corresponding to the correlation sequence with the largest peak value is taken as the final modulation index.

[0017] Furthermore, in step 1, the relationship between the packet error rate and the sensitivity threshold of the receiving link under different modulation indices is obtained by querying the measured performance curves of different modulation indices.

[0018] Furthermore, the method for obtaining the measured performance curve is:

[0019] Under the condition of known modulation index, change the received signal strength, test the packet error rate of the receiving link at different signal strengths, and draw the measured performance curve, with the horizontal axis representing the received signal strength and the vertical axis representing the packet error rate.

[0020] Furthermore, in step 2, the number of steps for reducing the transmit power is determined as follows:

[0021] Assume that the AGC module gain is The minimum amount of downgrade in each group is The transmitting power is also reduced. steps, one step is ;

[0022] When the LGMT module monitors the level and the upper limit is not exceeded, and the ADC module overflows, the transmit power is reduced. stairs, symbol Indicates rounding down.

[0023] Furthermore, step 2 also includes determining whether the transmit power is increased, specifically including:

[0024] If the recently received In the groups, more than If there are error packets, the judgment of whether to increase the transmission power is turned on and the calculation is The average received signal strength of the packets , calculate the difference ,like , the transmit power is increased steps, where the symbol Indicates rounding up; if , then there is no need to increase the transmit power, where, represents the number of groups for one observation, express The number of error packets in the group, , .

[0025] Further, in step 2, continuously observations, and the number of groups per observation is ,like In the observation The judgment of whether the transmission power is increased is turned on for the second time, and the transmitting end is notified to jump to other frequencies, among which, is the number of consecutive observations, for The number of times the transmit power is increased in the observation. , .

[0026] Further, .

[0027] Compared with the prior art, the multi-parameter joint adaptive power control method of a short-range wireless Internet of Things chip provided by the present invention has the following beneficial effects:

[0028] (1) There is no need to adjust the power after transmitting a large amount of packet data. By obtaining the indication signal of the amplified part of the receiving link, the power adaptation of wireless communication can be achieved more quickly and the response is more sensitive;

[0029] (2) The received signal strength threshold is determined according to specific business requirements. When the business requirements are different, the received signal strength threshold is also different, which improves the flexibility of the product and has a wider range of applications;

[0030] (3) A specific method for determining the received signal strength threshold is given, which is more accurate than determining it based on experience and ensures the accuracy of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for determining whether the transmission power needs to be lowered;

[0032] Figure 2 This is a schematic diagram of the structure of the 2.4G IoT chip receiving end;

[0033] Figure 3 When the actual modulation index is 0.32, the correlation sequence is calculated according to the modulation indexes of 0.375, 0.5, and 0.625 respectively. DETAILED DESCRIPTION

[0034] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments.

[0035] A multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip comprises the following steps:

[0036] Step 1: Determine the modulation index of the short-range wireless IoT chip, and determine the sensitivity threshold based on the relationship between the packet error rate and the sensitivity threshold of the receiving link under different modulation indices. , according to the sensitivity threshold and redundancy Determine the received signal strength threshold .

[0037] Since different services have different real-time requirements, the tolerable packet error rate is different. For example, some services have low real-time requirements, and a PER of 30% is acceptable; some services have high real-time requirements, and a PER of less than 1% is required. Therefore, compared with the former, the latter's transmission power obviously needs to be set higher. Therefore, it is necessary to determine the sensitivity threshold according to the packet error rate requirement.

[0038] 2.4G custom short-distance IoT chips usually use GFSK modulation, but the modulation index varies, typically 0.32, 0.5, 0.75, etc. Therefore, from the perspective of the matching and adaptability of communication products, the designed chip needs to have strong adaptability to multiple modulation indexes. Signals with different modulation indexes have different sensitivity indicators. The smaller the modulation index, the more serious the phase interference of the previous and next symbols on the phase of the transmitted signal of the current symbol. Therefore, while ensuring that the demodulation complexity is appropriate, its sensitivity index is worse. Therefore, the modulation index is also a factor in determining the sensitivity threshold.

[0039] The relationship between the packet error rate and the sensitivity threshold of the receiving link under different modulation indices can be obtained by querying the measured performance curves of different modulation indices. The method for obtaining the measured performance curves is:

[0040] Under the condition of known modulation index, change the received signal strength, test the packet error rate of the receiving link at different signal strengths, and draw the measured performance curve, with the horizontal axis representing the received signal strength and the vertical axis representing the packet error rate.

[0041] For example, a service requires PER to be below 1%, and the modulation index of the transmitted signal is 0.5. Based on the performance curve of the chip measured on the relationship between received power and PER, the sensitivity threshold is determined. ,For example . And determine the amount of redundancy ,For example . The received signal strength is required to be And set the group counter , used to receive packet counts.

[0042] Step 2: During the communication process, if the receiving end receives the ( ,For example =16) packets, the judgment on whether to reduce the transmission power is started, including:

[0043] Get multiple parameters of the receiving end. The structure of the receiving end is as follows Figure 2 As shown in the figure, two level detection points are set, one is located behind the LGMT module (LGMT module is the abbreviation of the combination of LNA module and Gm+Mixer+TIA module, LNA module is low noise amplifier, Gm is transconductance, Mixer is mixing, TIA is transimpedance), that is, Figure 2 The first level monitoring point in the ADC module. Figure 2 The chip's AGC (Auto Gain Controlling) module will adjust the gain according to the situation that the first level monitoring point (LGMT level monitoring point) exceeds the upper limit and the ADC module overflow occurs at the second level monitoring point. Multiple parameters include the level of the LMGT module, the overflow of the ADC module, and the signal strength of the received packet;

[0044] According to multiple parameters and the received signal strength threshold , comprehensively judge whether it is necessary to reduce the transmission power, such as Figure 1 As shown, specifically including:

[0045] If the AGC module adjusts the gain down because the LGMT module monitoring level exceeds the upper limit, it means that the sending end must have too high a sending power, so the sending power is adjusted down. (For example ) is a step, and the adjustment amount is several steps at a time. Assume that the AGC module gain is The minimum amount of downgrade in each group is The transmitting power is also reduced. steps;

[0046] If the LGMT module monitoring level does not exceed the upper limit, but the ADC module overflows, it is necessary to combine the RSSI estimation value to determine whether the transmit power can be reduced. The average received signal strength of the packets , calculate the difference ,like , the transmit power is reduced stairs, symbol Indicates rounding down; if the ADC module does not overflow, there is no need to reduce the transmit power.

[0047] In addition to reducing the transmit power when the transmit power is too large, sometimes the transmit power may be too small, which requires a judgment on whether to increase the transmit power. Specifically, the following are included:

[0048] If the recently received (For example =128) groups, more than If there are error packets, the judgment on whether to increase the transmission power is started. represents the number of groups for one observation, Indicates the number of error packets, value range: , , in fact, it must also meet .calculate The average received signal strength of the packets , calculate the difference ,like , the transmit power is increased steps, where the symbol Indicates rounding up; if , there is no need to increase the transmit power. The value of the parameter is related to the PER requirement of the service. For example, if the PER is required to be below 1%, then Desirable .

[0049] Can be performed continuously observations, and the number of groups per observation is ,like (For example =4) in observations (For example =2) If the judgment on whether to increase the transmission power is turned on for the second time, it means that there is serious interference on the communication frequency. At this time, it is necessary to notify the sending end to jump to other frequencies. is the number of consecutive observations, for The number of times the transmit power is increased in the observation. , .

[0050] In step 1, if the modulation index is a priori information, the sensitivity threshold can be determined directly based on the modulation index; but if the modulation index is unknown, it is necessary to estimate the modulation index. The existing technology estimates it through methods such as high-order statistics, but its calculation is relatively complicated and requires a sufficient number of sample points involved in the estimation. It is not suitable for use in power control and affects the rapid adjustment of the transmission power. Therefore, this embodiment provides a modulation index estimation method based on phase trajectory correlation, which can quickly estimate the modulation index with fewer sample points and lower computational complexity. Specifically including:

[0051] Since the address sequence is known to both the sender and the receiver, the phase trajectory of the GFSK signal is obviously different when the modulation parameters are different. Therefore, multiple local reference sequences are set at the receiving end according to different modulation indices, which are recorded as: , is the number of modulation indices, For the The conjugate value of the transmitted signal of the address sequence portion corresponding to the modulation index, is the length of the reference sequence. For example, if the address sequence length is 32 and the oversampling factor is 4, then L The length of is 128;

[0052] Get the received signal after frequency offset correction, denoted as ;

[0053] Calculate the correlation sequence , Indicates that through i Reference sequences and receive signals The modulation index of the reference sequence corresponding to the correlation sequence with the largest peak value is taken as the final modulation index.

[0054] For example, when the actual modulation index of the transmitted signal is 0.32 and the received signal strength is -94dBm, Figure 3 (a), (b), and (c) are the results of correlation with three local reference sequences with modulation indexes of 0.375, 0.5, and 0.625, respectively. It can be clearly seen from the figure that when the modulation index of the reference sequence is close to the actual modulation index, a very large correlation peak appears; the greater the difference between the two, the smaller the correlation peak. Therefore, the modulation index of the received signal can be quickly estimated by the method based on the correlation of the phase trajectory, thereby determining the sensitivity threshold.

[0055] A short-range wireless Internet of Things chip adopts the multi-parameter joint adaptive power control method of the short-range wireless Internet of Things chip to achieve power adaptation.

[0056] Through the above solution, the signal transmission power can be kept within an appropriate range, thereby achieving the purpose of reducing power consumption while meeting the PER requirements of the service.

Claims

1. A multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip, characterized in that: The following steps are involved: Step 1: Determine the modulation index of the short-range wireless IoT chip, and determine the sensitivity threshold based on the relationship between the packet error rate and the sensitivity threshold of the receiving link under different modulation indices. , according to the sensitivity threshold and redundancy Determine the received signal strength threshold ; Step 2: During the communication process, if the receiving end receives the Groups, , then the judgment of whether to reduce the transmission power is started, specifically including: Acquisition of multiple parameters at the receiving end, including the gain adjustment of the AGC module, the overflow of the ADC module, and the signal strength of the received packet; According to multiple parameters and the received signal strength threshold , comprehensively judge whether it is necessary to reduce the transmit power, including: If the AGC module adjusts the gain downward because the monitoring level of the LGMT module exceeds the upper limit, the transmission power is adjusted downward, and the LGMT module includes a low noise amplifier and a transconductance + mixer + transimpedance module; If the LGMT module monitoring level does not exceed the upper limit, but the ADC module overflows, then calculate The average received signal strength of the packets , calculate the difference ,like , the transmit power is reduced; if the ADC module does not overflow, there is no need to reduce the transmit power.

2. The multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip according to claim 1 is characterized in that: In step 1, the method for determining the modulation index includes: At the receiving end, multiple local reference sequences are set according to different modulation indices, which are recorded as: , is the number of modulation indices, For the The conjugate value of the transmitted signal of the address sequence portion corresponding to the modulation index, is the length of the reference sequence; Get the received signal after frequency offset correction, denoted as ; Calculate the correlation sequence , the modulation index of the reference sequence corresponding to the correlation sequence with the largest peak value is taken as the final modulation index.

3. The multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip according to claim 1 is characterized in that: In step 1, the relationship between the packet error rate and the sensitivity threshold of the receiving link under different modulation indices is obtained by querying the measured performance curves of different modulation indices.

4. The multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip according to claim 3 is characterized in that: The method for obtaining the measured performance curve is: Under the condition of known modulation index, change the received signal strength, test the packet error rate of the receiving link at different signal strengths, and draw the measured performance curve, with the horizontal axis representing the received signal strength and the vertical axis representing the packet error rate.

5. The multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip according to claim 1 is characterized in that: In step 2, the number of steps for reducing the transmit power is determined as follows: Assume that the AGC module gain is The minimum amount of downgrade in each group is The transmitting power is also reduced. steps, one step is ; When the LGMT module monitors the level and the upper limit is not exceeded, and the ADC module overflows, the transmit power is reduced. stairs, symbol Indicates rounding down.

6. The multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip according to claim 5 is characterized in that: Step 2 also includes determining whether the transmit power is increased, specifically including: If the recently received In the groups, more than If there are error packets, the judgment of whether to increase the transmission power is turned on and the calculation is The average received signal strength of the packets , calculate the difference ,like , the transmit power is increased steps, where the symbol Indicates rounding up; if , then there is no need to increase the transmit power, where, represents the number of groups for one observation, express The number of error packets in the group, , .

7. The multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip according to claim 6 is characterized in that: In step 2, continue observations, and the number of groups per observation is ,like In the observation The judgment of whether the transmission power is increased is turned on for the second time, and the transmitting end is notified to jump to other frequencies, among which, is the number of consecutive observations, for The number of times the transmit power is increased in the observation. , .

8. The multi-parameter joint adaptive power control method for a short-range wireless Internet of Things chip according to claim 6 is characterized in that: 。

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