Power compensation determination for radio frequency cables

Abstract

The embodiment of the invention relates to power compensation determination for a radio frequency cable. In an embodiment of the present disclosure, a power compensation determination mechanism for a radio frequency cable is provided. An access point (AP) determines a time slot for RF cable loss measurements on an RF cable and sends a test signal over the RF cable to an antenna module at a first TX power. The AP also obtains a second TX power transmitted by the antenna module and determines an RF cable loss based on the first TX power and the second TX power. The AP also determines a power compensation for the RF cable based on the determined RF cable loss, the first TX power, and an antenna gain of the antenna module. The AP sends a signal over the RF cable to the antenna module based on the determined power compensation. Embodiments of the present disclosure may automatically determine power compensation based on RF cable loss.

Description

Background Art

[0001] In the Wi-Fi world, Multiple Input Multiple Output (MIMO) technology refers to the practice of housing two or more antennas in a single wireless device. The access point (AP) has multiple antennas that can be used to receive and send data simultaneously, enabling faster data transfer rates. In modern society, the speed at which data is sent is critical to any network device, so MIMO technology has become commonplace in network devices since it was adopted in the Wi-Fi 4 standard.

[0002] As smartphones are becoming more and more popular among people nowadays, wireless access is always necessary in outdoor environments. For example, when a group of people have a party or work in the garden or wirelessly connect outdoor cameras or outdoor speakers, Wi-Fi coverage is very important. APs installed indoors cannot provide a smooth Wi-Fi experience outdoors due to limited coverage and signal attenuation. Therefore, installing outdoor Wi-Fi access points is a common way to provide outdoor Wi-Fi. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] When read in conjunction with the accompanying drawings, embodiments of the present disclosure can be understood from the following detailed description. According to standard practice in the industry, various features are not drawn to scale. In fact, for the sake of clarity of discussion, the dimensions of various features can be increased or reduced arbitrarily. Some examples of the present disclosure are described with reference to the following drawings.

[0004] Figure 1 illustrates an example network environment in which example implementations of the present disclosure may be implemented;

[0005] Figure 2 illustrates an example diagram of a smart antenna module (SMA) used as a power meter according to an embodiment of the present disclosure;

[0006] Figure 3 An example flow chart illustrating an example process for determining transmit power compensation according to an embodiment of the present disclosure is illustrated;

[0007] Figure 4 An example block diagram of performing RF cable loss measurement without a SAM according to an embodiment of the present disclosure is illustrated;

[0008] Figure 5 illustrates an example relationship between RF cable loss and frequency related to embodiments of the present disclosure;

[0009] Figure 6 illustrates an example graph of RF cable loss determined by an interpolation algorithm according to an embodiment of the present disclosure;

[0010] Figure 7 An example flow chart illustrating an example method for determining transmit power compensation according to an embodiment of the present disclosure; and

[0011] Figure 8 An example AP according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0012] In Wi-Fi deployments, it is necessary to balance the AP transmit (TX) power across all radio frequency (RF) chains. It should be understood that the TX power values ​​of signals sent from different antennas should be the same. Otherwise, the MIMO transmit performance and / or efficiency will be affected. The traditional barrel theory describes that for an upright barrel with different wall lengths, the contents that the barrel can hold are not determined by the taller planks, but by its shortest planks. Similarly, the lowest power value across all RF chains will determine the AP throughput value, as the lowest power value will affect the TX performance. For example, the modulation coding scheme (MCS), number of spatial streams (NSS), and bandwidth (BW) in the rate control module can be lowered or reduced.

[0013] There are several reasons that may cause unbalanced TX power per chain. The first reason is unknown RF cable loss. RF cable loss can refer to the amount of power lost over the length of the cable. For example, the longer the cable, the more power is lost. The second reason is an aging or loosely mounted antenna. This situation can often occur in actual deployment sites because the antennas and RF cables are located outdoors. The third reason is regulations or requirements, such as the automatic frequency coordination (AFC) requirement for the 6 Gigahertz (GHz) band.

[0014] Therefore, in order to solve the problem that it is difficult to determine the unknown RF cable and the output power is different from the target transmission power, it is necessary to introduce a solution for automatically determining the power compensation based on the determined RF cable loss. In some example embodiments, the proposed solution can further ensure that the impact on MIMO transmission is small due to less gain variation. In some example embodiments, the proposed solution can further ensure the throughput efficiency or performance of the AP system. In some example embodiments, the proposed solution can further improve the competitiveness with other manufacturers in using smart antenna modules.

[0015] In general, according to an embodiment of the present disclosure, an AP determines a time slot for performing RF cable loss measurement on an RF cable of the AP. The AP is coupled to a plurality of RF cables, and the plurality of RF cables include the RF cable. The AP transmits a test signal to an antenna module at a first TX power through the RF cable during the time slot. The AP obtains a second TX power transmitted by the antenna module during the time slot. The AP determines the RF cable loss based on the first TX power and the second TX power. The AP determines a power compensation for the RF cable based on the determined RF cable loss, the first transmit power, and the antenna gain of the antenna module. The AP transmits a signal to the antenna module on the RF cable based on the determined power compensation.

[0016] As an example, if RF cable loss measurement is required, the AP can be set to test mode when the AP starts up. The AP can define a time slot, such as a time during the AP startup process, and switch the operating mode to test mode. The AP can send a fixed duty cycle signal on a single chain. The AP knows the TX power value and records it as P1. During the test mode, the antenna module (working as an RF power detector) can report the RF power as P2. By calculating the value of P1-P2, the RF cable loss can be determined. In some example embodiments, the RF cable loss measurement can be performed multiple times, and the average value can be used as the RF cable loss. Then, by switching the RF chain switch, the RF cable loss measurement process can be completed on other RF chains until all RF chains are tested. After measuring the RF cable loss of all RF chains, the AP can determine the power compensation for each RF chain, and the AP can send a signal on each RF chain to the antenna module based on the power compensation determined respectively.

[0017] This RF cable power compensation determination mechanism can automatically determine the power compensation based on the RF cable loss. In some embodiments, for a MIMO AP, this mechanism can be used for each of the multiple RF cables, and then the corresponding RF cable loss can be determined. Therefore, the power compensation for each RF cable can be determined, so that the transmit power balance can be automatically maintained. It can be used to ensure a high throughput value sent on the AP. The advantages of the embodiments of the present disclosure will be described below with reference to example embodiments. Figures 1 to 8 Reference is made to illustrate the general principles and several example implementations disclosed herein.

[0018] Reference now Figure 1 , which illustrates an example network environment 100 in which example implementations of the present disclosure may be implemented. Figure 1As shown in FIG. 1 , network environment 100 includes AP 102 and multiple antennas, such as antenna 106, antenna 108, and antenna 110. AP 102 supports MIMO, and AP 102 can operate on the 2.4 GHz band. AP 102 can also operate on the 5 GHz band and the 6 GHz band.

[0019] For each frequency band, the AP may use a corresponding RF cable to send a signal. For example, the AP 102 may use the RF cable 112 to send a 2.4 GHz frequency band signal. The AP 102 may use the RF cable 114 to send a 5 GHz frequency band signal. The AP 102 may use the RF cable 116 to send a 6 GHz frequency band signal. It is understood that, with the development of Wi-Fi technology in the future, there may be more frequency bands, and the present disclosure supports such future development.

[0020] The AP 102 may include a compensation module 104. The compensation module 104 may have features that enable implementations of the present disclosure. For each RF chain (such as 2.4 GHz, 5 GHz, and 6 GHz), the compensation module 104 may measure their respective RF cable losses, and the compensation module 104 may determine a respective transmit power compensation for each RF cable. The AP 102 may transmit signals on the RF cables based on the respective transmit power compensation for each RF cable.

[0021] It should be understood that the order of the RF cables used for different RF frequency bands is not limited to the order in which they are used. Figure 1 In addition, it should be understood that Figure 1 In the present disclosure as a whole, the number of any elements is for illustrative purposes only and does not imply any limitation.

[0022] In order to better understand the embodiments of the present disclosure, it is necessary to introduce the smart antenna module (SMA) related to the embodiments of the present disclosure. Figure 2 , which illustrates an example diagram 200 of an SMA being used as a power meter according to an embodiment of the present disclosure.

[0023] like Figure 2 As shown in , SMA 212 can enable AP 202 to automatically adjust antenna parameters based on client location and channel information to improve signal quality and stability. SMA 212 can improve signal strength at the same location as before and improve the Wi-Fi speed experienced by the user. In this way, fewer APs are required, thereby reducing the customer's investment. However, in an embodiment of the present disclosure, SMA 212 can be used as a power meter or power detector.

[0024] As shown inside the SMA 212, there is a chain switch 216. The chain switch 216 can be connected to the antenna element 214, where the signal will be sent to the antenna element 214 into the air. By switching the chain switch 216, the corresponding RF cable can be connected to the analog-to-digital converter (ADC) 218. The ADC 218 can convert the RF signal into a digital value of the RF signal and report the value of the RF signal to a bus (such as an inter-integrated circuit (IIC) bus). The AP 202 can check the IIC bus to read the value.

[0025] Similarly, AP 202 also includes a chain switch 210. By switching the chain switch 210, a corresponding signal is sent on a corresponding RF cable. For example, a 2.4 GHz signal may be sent on RF cable 220, and a 5 GHz signal may be sent on RF cable 222. RF cable 220 may be connected to AP 202 via port 204, such as an MMCX connector.

[0026] In some cases, for the RF cable installed between the AP Reverse Polarity Subminiature Type A (RPSMA)(N) and the N-type connector of the outdoor AP, customers are allowed to equip RF cables of different types or lengths for different outdoor user scenarios, and the AP equipment installer must enter the RF cable loss values ​​of different RF cables by themselves. After the RF cable loss values ​​of different RF cables are entered, static cable loss values ​​and antenna gain values ​​will be provided to supply or configure the AP. This is a relatively rough measurement process. For example, people have to connect both ends of the RF cable to the power meter equipment, and it may take a long time to measure. This is another reason why it is difficult to determine the RF cable loss.

[0027] RF cable 222 may be connected to AP 202 via port 206. AP 202 may include CPU 208. It should be understood that CPU 208 is shown for illustrative purposes. AP may include other processors capable of implementing embodiments of the present disclosure. Figure 2 For reference.

[0028] After introducing SAM 212, now refer to Figure 3 , which illustrates an example flow chart of an example process 300 for determining a transmit power offset according to an embodiment of the present disclosure. In process 300, two scenarios for determining a transmit power offset are described. One scenario describes determining a transmit power offset using a SAM (such as steps 310, 312, and 314), and the other scenario describes determining a transmit power offset without a SAM (such as steps 316, 318, and 320).

[0029] At 302, the AP 202 may be started before Wi-Fi is available. In some example embodiments, the AP 202 may transition from an operational mode to a test mode. In the test mode, the AP 202 may define a time slot during the startup process. At 304, the AP 202 may check whether an RF cable loss table is available. The RF cable loss table may record the RF cable loss for each RF cable. Therefore, if the RF cable loss table is available, then the RF cable loss may not need to be measured again. Therefore, the process 300 may continue to 306. At 306, the AP 202 may continue to start up, and the AP 202 may transition to an operational mode.

[0030] If it is determined at 304 that the RF cable loss meter is not available, process 300 may continue to 308. At 308, AP 202 may check whether SAM 212 is available. If SAM 212 is available, SAM 212 may be used as a power meter, and thus process 300 may continue to 310. If SAM 212 is not available, process 300 may continue to 316, where a nearby AP may be used to measure RF cable loss.

[0031] At 310, the AP may measure RF cable loss using the SAM 212. RF cable loss may refer to the amount of power lost in a cable over its length. For example, the longer the cable, the more power is lost. Another term for cable loss is "insertion loss." Cable loss may be a factor to consider in system design for outdoor Wi-Fi deployments. Signal leakage may be caused by loose connectors, damaged equipment or cables, or unterminated cables (not connected to a device, panel, or wall outlet).

[0032] For example, AP 202 may select RF cable 220 for measurement. During the time slot, AP 202 may send a fixed duty cycle signal. In some example embodiments, the fixed duty cycle signal may be a sine wave. In some example embodiments, the duty cycle signal may be a (802.11n, HT20, mcs0, TX99) signal (a designated TX signal as defined in the 802.11n specification). It should be understood that other fixed duty cycle signals may also be suitable for test mode.

[0033] The test signal transmitted by AP 202 may be at a TX power referred to as P1. During the test, for one time slot (such as 100 milliseconds), SAM 212 may report the received RF power to ADC 218. In some example embodiments, the received RF power may have an accuracy of 1 dB, but this is only an example and not a limitation.

[0034] AP 202 (e.g., CPU 208) may check the IIC bus to read the power value and record the power value as P2. By calculating P1-P2 as the RF cable loss, the RR cable loss may be determined. In some example embodiments, this measurement may be repeated multiple times, such as 5 times. AP 202 may take the average value as the final RF cable loss of RF cable 220.

[0035] After measuring the RF cable loss of RF cable 220, AP 202 may select other RF cables by switching chain switch 216. For example, RF cable 222 may be selected for measurement. These measurements may be performed until all RF cables are tested.

[0036] At 312, AP 202 may save the measured RF cable loss of each RF cable into its flash memory as an RF cable loss table. At 314, AP 314 may continue the startup process, and a basic service set (BSS) may be started.

[0037] In some example embodiments, after determining the RF cable loss of the RF cable, the power compensation may be further determined. In some example embodiments, if the RF cable loss table already exists, the power compensation may also be determined. According to example embodiments of the present disclosure, an RF loss compensation algorithm is proposed. Before introducing the RF loss compensation algorithm, some terms are introduced to help understand the RF loss compensation algorithm.

[0038] As used herein, the target power may be a user-configured power value in equivalent isotropic radiated power (EIRP) in decibels relative to one milliwatt (dBm). It is also referred to as software-programmed TX power. This is the user's target power value and may be changed after power compensation.

[0039] The antenna gain may be the actual antenna gain (dB) value on different chains. The antenna gain value is related to the channel frequency. Different antenna gain values ​​may be used in different APs. The external antenna gain connected to the AP may be stored as a supply parameter, and the internal antenna gain may be defined in the AP configuration table. The antenna gain value table may be provided by the factory, and therefore the values ​​are static. In some older designs, only one maximum antenna gain value is required for all RF chains and all frequencies, taking into account the requirements of the Federal Communications Commission (FCC).

[0040] The RF cable loss may be a negative gain (dB) value in the RF cable. The compensated target power may be a TX power value (in dBm) programmed using compensation software of the antenna connector. The output power may be an actual TX power output value using the antenna. The maximum output power limit may be limited by board limitations, area, AFC requirements, etc. If the actual output power value reaches the maximum output power limit, the actual output power value needs to be limited to a certain value, and thus it may be considered as a threshold.

[0041] For example, the Automatic Frequency Coordination (AFC) requirement for the 6GHz band. It should be understood that AFC is a system that calculates available frequencies based on the location information of unlicensed devices. The AFC system can use information about existing systems to determine the operating channels and different TX power limits for the availability of the standard power (SP) TX mode in a specific location, so AFC-certified APs need to correct their equivalent isotropic radiated power (EIRP) to comply with the requirements of the AFC system.

[0042] Antenna gain and RF cable loss are on a per-channel and per-chain basis, and the goal is to achieve equal actual transmit power at the antenna, and for a particular channel, the output power can be described as follows by equations (1)–(3):

[0043] CompTarge tPower = target power - antenna gain - RF cable loss (1)

[0044] powerLimit = Min (board, area, AFC, etc.) (2)

[0045] Output power = Min (target power, power limit) (3) Where CompTargetPower represents the target power after compensation; Min represents the operation of determining the minimum value. It should be understood that when performing calculations, all unit-related formulas can be unified into the same unit system.

[0046] As an example, before compensation, if the target power is 20dB, the RF cable loss is -3dB, the antenna gain is 5dB, and the actual output power is 20-3+5=22dB. According to formula (1), the target power after compensation is 20-5-(-3)=18dB. According to formula (2), the power limit in this example is 25dB. Therefore, after compensation, according to formula (3), the output power is the minimum of 20 and 25, which is 20dB in this example. Therefore, the actual TX power sent by the final antenna is the compensated target power-RF cable loss+antenna gain, which is equal to 18-3+5=20dB, which meets the required output power.

[0047] As a detailed example, Tables 1 and 2 show the case of a 4x4 MIMO AP operating on 5G channel 36. Assuming that all power values ​​are less than the power limit, the following power relationship may be present, as shown in Table 1 below.

[0048] Table 1 Before compensation

[0049]

[0050]

[0051] Table 2 shows how to determine the compensation target power value after compensation.

[0052] Table 2 After compensation

[0053]

[0054] It can be seen that before compensation, the output power of all RF chains is different. After compensation, the output power of all RF chains is balanced to 20dB. The factory or manufacturer can perform full-band TX power calibration on the antenna gain, so the antenna gain value is a known value, but the RF cable loss value is determined based on the actual RF cable usage in the customer's product environment, and therefore a solution needs to be designed for measuring the RF cable loss even without SMA.

[0055] As discussed above, if SAM 212 is not available, process 300 may continue to 316 where a nearby AP may be used to measure RF cable loss. At 306, AP 202 may continue to the startup process. At 318, AP 202, after being prepared, performs RF cable loss measurements without SAM. Figure 4 The details of the method for performing RF cable loss measurements without SAM are described and therefore are not discussed here for the sake of brevity.At 320, AP 202 may save the RF cable loss table to its flash memory.

[0056] Now to Figure 4 Reference is made, which illustrates an example block diagram 400 of performing RF cable loss measurements without a SAM according to an embodiment of the present disclosure. Figure 4 The high-level idea is that if you set the transmit power of a frame and try to get its received signal strength indication (RSSI) signal from a monitoring device, you can check the RF cable loss measurement. Since the user sets the absolute transmit power of each RF chain, the final test process can be to measure the absolute power of the frame generated by the AP, and this test process can be completed after the AP starts Wi-Fi service.

[0057] like Figure 4As shown in FIG. , AP 402 may correspond to Figure 1 The compensation module 404 may correspond to Figure 1 1. The compensation module 104 in FIG. RF cables 412, 414, and 416 may correspond to RF cables 112, 114, and 116, respectively. Antennas 406, 408, and 410 may correspond to antennas 106, 108, and 110. For the sake of brevity, these similar elements will not be described again.

[0058] AP 402 may select a nearby AP (e.g., AP 418) as a monitoring AP. In this case, AP 402 may be referred to as a working AP. AP 402 may attempt to estimate the air path loss from working AP 402 to monitoring AP 418. The air path loss estimation algorithm method is related to parameters such as distance, channel band, channel frequency, etc. Air path loss is the loss of signal strength as the signal travels through free space (such as air). This value is typically calculated by deducting any obstacles or reflections that may appear in its path. These parameters are used as inputs, and an estimate of the air path loss can be calculated.

[0059] AP 402 may select an appropriate test time and duration. This may require negotiation between the working AP 402 and the monitoring AP 418. The monitoring AP 418 may need to capture a test frame from the working AP 402. In some example embodiments, some suggestions may be used to avoid traffic interruption. For example, the test frame may be unicast, fixed rate, fixed TX power value for a single chain (power limit not reached), and traditional (non-high throughput (HT), non-very high throughput (VHT), or non-high efficiency (HE)). For another example, the test process may be within the scan dwell time on the working AP 402. For another example, before testing on the working AP 402, multi-user (MU) may be temporarily disabled, and the client does not need to be deauthenticated after disabling the MU function (MIMO / orthogonal frequency division multiple access (FDMA)). For another example, a request to send / clear to send (RTS / CTS) or a quiet Internet browser (IE) cycle may be used to protect the test process.

[0060] AP 402 can adjust the TX chain mask to single chain mode on the working AP 402, and can capture packets on the monitoring AP 418 when it is time to test and all chains need to be tested. AP 418 can decode the RSSI value from the captured packet and the noise factor (NF) value (in dBm, here a positive value) on the monitoring AP 418 from the air path 420. AP 402 can calculate the received (RX) signal strength based on the signal-to-noise ratio (SNR) value, and the value can be an average, maximum, or minimum value. The formula is as follows:

[0061] RSSI = RX signal strength = NF + SNR (4)

[0062] AP 402 can calculate the TX signal strength (output power of the working AP 402) value and RF cable loss by using equations (5)-(6) as follows:

[0063] TX signal strength = RX signal strength - air path loss (5)

[0064] RF cable loss = output power - antenna gain (6) Formula (6) can be rewritten as formula (7) as follows:

[0065] RF cable loss = NF + SNR - air path loss - antenna gain (7)

[0066] It is important to understand that the NF, RSSI, and air path loss values ​​may introduce unwanted bias, and more testing can be done to ensure the accuracy of the RF cable loss.

[0067] By implementing Figure 4 According to the example implementation of , even without SMA, RF cable loss can still be estimated. Therefore, the use case is extended to almost all outdoor Wi-Fi deployments, because almost all outdoor Wi-Fi deployments have two or more APs.

[0068] Now refer to Figure 5 , which illustrates an example relationship 500 between RF cable loss and frequency related to embodiments of the present disclosure. As discussed above, for a MIMO AP, assuming the number of channels is N, and the number of RF chains is C, the value required to perform RF cable loss measurements is N times C. To speed up this process, according to some embodiments of the present disclosure, N can be reduced by using an interpolation algorithm for some test point values ​​at different frequencies. Figure 5 The relationship between RF cable loss and frequency is shown.

[0069] like Figure 5 As shown in FIG. 5 , curve 502 represents the RF cable loss of RF cable 1 and curve 514 represents the RF cable loss of RF cable 2. Points 504, 506, 508, 510, and 512 are points that have been measured. Curve 502 is determined by using an interpolation algorithm based on points 504, 506, 508, 510, and 512. Similarly, points 504, 506, 508, 510, and 512 are points that have been measured. Curve 514 is determined by using an interpolation algorithm based on points 516, 518, 520, 522, and 524.

[0070] from Figure 5 As can be seen in Table 3, the relationship between RF cable loss and frequency is nonlinear. Therefore, the interpolation algorithm is more accurate than the combination method, and it is necessary to ensure that all test point values ​​are correct with the test results. For example, for RF cables 1 and 2, the test point values ​​are shown in Table 3.

[0071] Table 3 Frequency and RF cable loss at test points

[0072] frequency 5.25 5.75 6.25 6.75 7.25 RF Cable Loss for Cable 1 -13 -18 -12 -13 -14 RF Cable Loss for Cable 2 -13 -10.5 -12 -17 -14

[0073] See also Figure 5 , points 504 and 516 represent 5.25 GHz. Points 506 and 518 represent 5.75 GHz, etc. Therefore, each cable has five test results over the entire 5 GHz and 6 GHz bands (five test points are sufficient for curve interpolation calculations).

[0074] Reference now Figure 6 , which illustrates an example graph 600 of RF cable loss determined by an interpolation algorithm according to an embodiment of the present disclosure. Figure 5 Based on this, since the relationship between RF cable loss and frequency is nonlinear, an interpolation algorithm such as Lagrange or Newton interpolation polynomials is recommended.

[0075] like Figure 6 As shown in FIG. 6 , dashed lines 602 and dashed lines 604 are determined by using the Newton interpolation method. The dashed portions of curves 602 and 604 can be used to fill in the full-band RF cable loss calculation. Therefore, the number of RF cable loss measurements can be saved. For example, for an AP, the number of channels is 16, and the number of RF chains is 3, then 16 x 3 = 48 RF cable loss measurements need to be performed. However, by using the Newton interpolation method, the number of times the RF cable loss measurement is performed is reduced to 10.

[0076] In some example embodiments, by using the above results, if any RF cable loss is much higher than other values, it may mean that the deviation value has reached a predefined threshold, then it may be necessary to try to perform a compensation process and warn the customer about the event, and the customer may need to be notified of the compensation results. In some example embodiments, some SMAs already have features for antenna and RF filter damage detection. However, this feature can be improved by RF cable loss compensation.

[0077] Reference now Figure 7 , which illustrates an example flow chart of an example method 700 for determining a transmit power compensation according to an embodiment of the present disclosure, and the method 700 may be performed by an access point such as AP 102. For clarity, reference will be made to Figure 1 .

[0078] At 702, the AP 102 determines a time slot for performing an RF cable loss measurement on an RF cable of the AP 102. As an example, the time slot for performing an RF cable loss measurement on the RF cable 112 of the AP 102 may be determined. At 704, the AP 102 transmits a test signal to the antenna module at a first TX power through the RF cable during the time slot. As an example, the AP 102 may transmit a sine wave signal to the antenna module 106 at a power P1 through the RF cable 112 during the time slot.

[0079] At 706, the AP 102 obtains a second TX power transmitted by the antenna module during the time slot. As an example, the AP 102 may obtain a power value of P2 as the second TX power transmitted by the antenna module 106 during the time slot. At 708, the AP 102 determines an RF cable loss based on the first TX power and the second TX power. As an example, the RF cable loss may be determined by calculating a value of P1-P2.

[0080] At 710, the AP 102 determines a power compensation for the RF cable based on the determined RF cable loss, the first TX power, and the antenna gain of the antenna module. Figure 3 Referring to equation (1), AP 102 may determine the power value by subtracting the determined RF cable loss and antenna gain from P1.

[0081] At 712, the AP 102 sends a signal to the antenna module based on the determined power compensation. As an example, the AP 102 may determine to send the signal 106 to the antenna module by adding the determined RF cable loss to the compensated TX power. For the sake of brevity, the details of the RF cable loss determination process and the RF cable loss compensation process have been referred to. Figure 3 and Figure 4 was discussed and therefore will not be repeated here.

[0082] According to an embodiment of the present disclosure, a power compensation determination mechanism for an RF cable can automatically determine power compensation based on RF cable loss. In some example embodiments, it can further automatically maintain TX power balance. In some example embodiments, it can be used to ensure high throughput values ​​sent on the AP. Since the gain variation is small, the impact on MIMO transmission can be reduced. In some example embodiments, the throughput efficiency or performance of the AP system can be guaranteed. In some example embodiments, the proposed solution can improve competitiveness with other manufacturers in using smart antenna modules.

[0083] Now to Figure 8 Reference is made to , which illustrates an example access point 800 according to an embodiment of the present disclosure. Figure 8 As shown in FIG. 8 , the AP 800 includes at least one processor 810 and a memory 820 coupled to the at least one processor 810. The memory 820 stores instructions 822, 824, 826, 828, 830, and 832 to enable the processor 810 to perform actions according to an exemplary embodiment of the present disclosure. Figure 8 As shown in , the memory 820 stores instructions 822 for determining a time slot for performing RF cable loss measurement on an RF cable of an AP, wherein the AP is coupled to a plurality of RF cables, and the plurality of RF cables include the RF cable. The memory 820 also stores instructions 824 for sending a test signal to the antenna module at a first TX power through the RF cable during the time slot.

[0084] The memory 820 also stores instructions 826 to obtain a second TX power transmitted by the antenna module during the time slot. The memory 820 also stores instructions 828 to determine an RF cable loss based on the first TX power and the second TX power. The memory 820 also stores instructions 830 to determine a power compensation for the RF cable based on the determined RF cable loss, the first TX power, and the antenna gain of the antenna module. The memory 820 also stores instructions 832 to send a signal to the antenna module on the RF cable based on the determined power compensation.

[0085] The stored instructions and the functions that the instructions can perform can be referred to Figure 2-Figure 7 For the sake of brevity, the details of instructions 822, 824, 826, 828, 830 and 832 will not be discussed here.

[0086] The program code or instructions for executing the method of the present disclosure can be written in any combination of one or more programming languages. These program codes or instructions can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code enables the function / operation specified in the flow chart and / or block diagram to be realized when executed by the processor or controller. The program code or instructions can be executed completely on the machine, partially on the machine, executed as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0087] The program code or instructions for executing the method of the present disclosure can be written in any combination of one or more programming languages. These program codes or instructions can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code enables the function / operation specified in the flow chart and / or block diagram to be realized when executed by the processor or controller. The program code or instructions can be executed completely on the machine, partially on the machine, executed as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0088] In the context of the present disclosure, a machine-readable medium may be any tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or apparatus. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, equipment, or any suitable combination of the foregoing. More specific examples of machine-readable storage media will include: an electrical connection with one or more wires, a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0089] In addition, although the operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in a continuous order, or that all illustrated operations be performed to achieve the desired result. In some scenarios, multitasking and parallel processing may be advantageous. Certain features described in the context of separate embodiments may also be combined in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be separately implemented in multiple embodiments or in any suitable sub-combination.

[0090] In the foregoing detailed description of the present disclosure, reference is made to the accompanying drawings which form a part thereof and in which are shown by way of illustration examples of how the present disclosure may be practiced. These examples are described in sufficient detail to enable one of ordinary skill in the art to practice the examples of the present disclosure, and it is understood that other examples may be utilized and process, electrical and / or structural changes may be made without departing from the scope of the present disclosure.

Claims

1. A method comprising: determining, by an access point AP, a time slot for performing RF cable loss measurement on a radio frequency RF cable of the AP, wherein the AP is coupled to a plurality of RF cables, and the plurality of RF cables includes the RF cable; The AP transmits a test signal to the antenna module at a first transmit TX power through the RF cable during the time slot; acquiring, by the AP, a second TX power transmitted by the antenna module during the time slot; determining, by the AP, an RF cable loss based on the first TX power and the second TX power; determining, by the AP, power compensation for the RF cable based on the determined RF cable loss, the first TX power, and an antenna gain of the antenna module; as well as A signal is sent by the AP to the antenna module over the RF cable based on the determined power offset.

2. The method according to claim 1, further comprising: selecting, by the AP, a second RF cable from the plurality of RF cables, wherein the second RF cable is different from the RF cable; determining, by the AP, a second power offset for the second RF cable; as well as A signal is sent, by the AP, to the antenna module over the second RF cable based on the second power compensation for the second RF cable.

3. The method of claim 1 , wherein determining the power compensation for the RF cable based on the determined RF cable loss comprises: determining, by the AP, a power value by subtracting the determined RF cable loss and the antenna gain from the first TX power; as well as In response to determining that the power value is greater than a predetermined power limit, determining, by the AP, the predetermined power limit as the compensated TX power; or In response to determining that the power value is less than the predetermined power limit, the determined power value is determined by the AP as the compensated TX power. 4 . The method according to claim 3 , wherein the predetermined power limit comprises a minimum power value among at least the following: a board limit power, an area limit power, and an automatic frequency coordination (AFC) required power.

5. The method of claim 4, wherein sending the signal to the antenna module based on the determined power offset comprises: The signal is sent, by the AP, to the antenna module by adding the determined RF cable loss to the compensated TX power.

6. The method of claim 1 , wherein determining the RF cable loss based on the first TX power and the second TX power comprises: iteratively determining, by the AP, a set of second TX powers for a predetermined number of times; as well as The AP determines a difference between the first TX power and an average value of the set of second TX powers as the RF cable loss. 7 . The method of claim 6 , wherein RF cable losses for other RF cables of the plurality of RF cables are estimated based on a first RF cable loss for the first RF cable and a second RF cable loss for the second RF cable using an interpolation method.

8. The method according to claim 1, further comprising: The AP selects a second AP adjacent to the AP; Acquiring, by the AP, an air path loss from the AP to the second AP; The AP sends a test packet to the second AP; as well as The RF cable loss is determined by the AP based on a received signal strength indication RSSI value of the test packet received by the second AP, the air path loss, and a noise factor NF value of the second AP.

9. The method of claim 8, wherein the RF cable loss is determined by subtracting the air path loss and the antenna gain from a sum of the NF value and a signal-to-noise ratio (SNR) value associated with the RSSI value.

10. An access point AP, comprising: at least one processor; as well as a memory coupled to the at least one processor, the memory storing instructions to cause the at least one processor to: determining a time slot for performing RF cable loss measurements on a radio frequency (RF) cable of the AP, wherein the AP is coupled to a plurality of RF cables and the plurality of RF cables includes the RF cable; transmitting a test signal to an antenna module at a first transmit TX power through the RF cable during the time slot; obtaining a second TX power transmitted by the antenna module during the time slot; determining an RF cable loss based on the first TX power and the second TX power; determining a power compensation for the RF cable based on the determined RF cable loss, the first TX power, and an antenna gain of the antenna module; as well as A signal is sent to the antenna module over the RF cable based on the determined power offset.

11. The AP of claim 10, wherein the memory further stores instructions to cause the at least one processor to: selecting a second RF cable from the plurality of RF cables, wherein the second RF cable is different from the RF cable; determining a second power offset for the second RF cable; as well as A signal is sent to the antenna module over the second RF cable based on the second power compensation for the second RF cable.

12. The AP of claim 10, wherein the instructions for determining power compensation for the RF cable based on the determined RF cable loss include instructions for causing the at least one processor to: determining a power value by subtracting the determined RF cable loss and the antenna gain from the first TX power; and In response to determining that the power value is greater than a predetermined power limit, determining the predetermined power limit as the compensated TX power; or In response to determining that the power value is less than the predetermined power limit, the determined power value is determined as the compensated TX power.

13. The AP according to claim 12, wherein the predetermined power limit comprises a minimum power value of at least the following: a board limit power, an area limit power, and an automatic frequency coordination (AFC) required power.

14. The AP of claim 13, wherein the instructions for sending the signal to the antenna module based on the determined power offset include instructions for causing the at least one processor to: The signal is transmitted to the antenna module by adding the determined RF cable loss to the compensated TX power.

15. The AP of claim 10, wherein the instructions for determining the RF cable loss based on the first TX power and the second TX power comprise instructions for causing the at least one processor to: iteratively determining a set of second TX powers a predetermined number of times; and A difference between the first TX power and an average value of the set of second TX powers is determined as the RF cable loss.

16. The AP of claim 15, wherein RF cable losses for other RF cables of the plurality of RF cables are estimated based on a first RF cable loss for the first RF cable and a second RF cable loss for the second RF cable using an interpolation method.

17. A non-transitory computer-readable medium comprising instructions stored thereon, which when executed by an access point (AP) cause the AP to: determining a time slot for performing RF cable loss measurements on a radio frequency (RF) cable of the AP, wherein the AP is coupled to a plurality of RF cables and the plurality of RF cables includes the RF cable; transmitting a test signal to an antenna module at a first transmit TX power through the RF cable during the time slot; obtaining a second TX power transmitted by the antenna module during the time slot; determining an RF cable loss based on the first TX power and the second TX power; determining a power compensation for the RF cable based on the determined RF cable loss, the first TX power, and an antenna gain of the antenna module; as well as A signal is sent to the antenna module over the RF cable based on the determined power offset.

18. The non-transitory computer readable medium of claim 17, wherein the memory further stores instructions to cause the AP to: selecting a second RF cable from the plurality of RF cables, wherein the second RF cable is different from the RF cable; determining a second power offset for the second RF cable; as well as A signal is sent to the antenna module over the second RF cable based on the second power compensation for the second RF cable.

19. The non-transitory computer readable medium of claim 17, wherein the instructions for determining the power compensation of the RF cable based on the determined RF cable loss comprise instructions for causing the AP to: determining a power value by subtracting the determined RF cable loss and the antenna gain from the first TX power; and In response to determining that the power value is greater than a predetermined power limit, determining the predetermined power limit as the compensated TX power; or In response to determining that the power value is less than the predetermined power limit, the determined power value is determined as the compensated TX power.

20. The non-transitory computer readable medium of claim 19, wherein the predetermined power limit comprises a minimum power value of at least: a board limit power, an area limit power, and an automatic frequency coordination (AFC) required power.

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