Method for measuring power of received signal

Abstract

A method for measuring power of a received signal includes the following steps: determining N type(s) of sampling rate(s) of an analog-to-digital converter (ADC) according to a theoretical minimum sampling rate of the received signal; using the ADC to sample the received signal according to the N type(s) of sampling rate(s) within a period of sampling time and thereby obtaining sampling results; and measuring the power of the received signal according to the sampling results and the period of sampling time, wherein the theoretical minimum sampling rate is corresponding to a signal cycle of the received signal, the N is a positive integer, the N type(s) of sampling rate(s) is/are corresponding to N type(s) of sampling cycle(s), and any of the N type(s) of sampling cycle(s) and the signal cycle are coprime.

Claims

1. A method for measuring power of a received signal comprising: determining N type(s) of sampling rate(s) of an analog-to-digital converter (ADC) according to a theoretical minimum sampling rate of the received signal; obtaining sampling results from the ADC sampling the received signal according to the N type(s) of sampling rate(s) within a period of sampling time; and measuring the power of the received signal according to the sampling results and the period of sampling time, wherein the theoretical minimum sampling rate corresponds to a signal cycle of the received signal, the N is a positive integer, the N type(s) of sampling rate(s) correspond(s) to N type(s) of sampling cycle(s), the signal cycle is equivalent to a product of a signal-cycle coefficient and a unit of time, any of the N type(s) of sampling cycle(s) is equivalent to a product of a sampling-cycle coefficient and the unit of time, and the signal-cycle coefficient and the sampling-cycle coefficient are coprime.

2. The method of claim 1, wherein the theoretical minimum sampling rate is equal to two times a bandwidth of the received signal.

3. The method of claim 1, wherein when the N is equal to one, the N type of sampling cycle is a certain sampling cycle, and a total number of the sampling results is not less than a numerical value of the certain sampling cycle; and when the N is greater than one, the total number of the sampling results is not less than a numerical value of a maximum sampling cycle of the N types of sampling cycles.

4. The method of claim 1, wherein the step of measuring the power of the received signal includes: calculating and adding up power according to the sampling results and thereby obtaining total power; and dividing the total power by the period of sampling time and thereby obtaining average power as the power of the received signal.

5. A method for measuring power of a received signal, the method being performed by a wireless receiver and comprising: using an analog-to-digital converter (ADC) to sample the received signal according to multiple types of sampling rates within a period of sampling time and thereby obtaining sampling results, wherein the multiple types of sampling rates are corresponding to multiple types of sampling cycles, and the multiple types of sampling cycles are coprime to one another; and measuring the power of the received signal according to the sampling results and the period of sampling time.

6. The method of claim 5, wherein the period of sampling time is not shorter than a maximum sampling cycle of the multiple types of sampling cycles.

7. The method of claim 5, wherein the step of measuring the power of the received signal includes: calculating and adding up power according to the sampling results, and thereby obtaining total power; and dividing the total power by the period of sampling time and thereby obtaining average power as the power of the received signal.

8. A method for measuring power of a received signal, the method being performed by a wireless receiver and comprising: using an analog-to-digital converter (ADC) to sample the received signal according to N types of sampling intervals within a period of sampling time and thereby obtaining sampling results, wherein the N types of sampling intervals are randomly determined and the N is an integer greater than one; and measuring the power of the received signal according to the sampling results and the period of sampling time.

9. The method of claim 8, wherein the period of sampling time is not shorter than a maximum value of the N types of sampling intervals.

10. The method of claim 8, wherein the step of measuring the power of the received signal includes: calculating and adding up power according to the sampling results, and thereby obtaining total power; and dividing the total power by the period of sampling time and thereby obtaining average power as the power of the received signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 shows an exemplary wireless receiver for performing the method of the present disclosure.

[0011] FIG. 2 shows a received signal and incomplete sampling results of the received signal.

[0012] FIG. 3 shows an embodiment of the method of the present disclosure for measuring the power of a received signal.

[0013] FIG. 4 shows sampling results obtained with the method of FIG. 3.

[0014] FIG. 5 shows another embodiment of the method of the present disclosure for measuring the power of a received signal.

[0015] FIG. 6 shows yet another embodiment of the method of the present disclosure for measuring the power of a received signal.

[0016] FIG. 7 shows sampling results obtained with the method of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present specification discloses a method for measuring the power of a received signal. This method can measure the power of the received signal at an extraordinarily low sampling rate regardless of the Sampling Theorem.

[0018] FIG. 1 shows an exemplary wireless receiver for performing the method of the present disclosure. The wireless receiver 100 of FIG. 1 includes a mixer 110, a filter 120, a low sampling rate analog-to-digital converter (ADC) 130, and a power measurement circuit 140. The mixer 110 is configured to generate a low frequency signal S.sub.LF according to a high frequency signal S.sub.HF, wherein the high frequency signal S.sub.HF originates from a wireless signal received by an antenna (not shown in FIG. 1). The filter 120 is configured to generate a received signal S.sub.RX according to the low frequency signal S.sub.LF. The low sampling rate ADC 130 is configured to sample the received signal S.sub.RX according to one or multiple sampling rate(s) fs (i.e., one or multiple sampling cycle(s) Ts) and thereby generate sampling results S.sub.SPL. The power measurement circuit 140 is configured to measure the power of the received signal S.sub.RX according to the sampling results S.sub.SPL. It is noted that if the bandwidth of the received signal S.sub.RX is BW, the minimum sampling rate ƒ.sub.S_MIN (hereinafter referred to as “the theorical minimum sampling rate”) for sampling the received signal S.sub.RX is supposed to be not lower than 2BW (when the low sampling rate ADC 130 uses a real-number sampler) or BW (when the low sampling rate ADC 130 uses a complex-number sampler composed of a real-part sampler and an imaginary-part sampler) according to the Sampling Theorem; however, the present method allows the low sampling rate ADC 130 to sample the received signal at a sampling rate ƒ.sub.S lower than the theorical minimum sampling rate ƒ.sub.S_MIN to reduce the total sampling times and consequently reduce the power consumption of the wireless receiver 100. It is also noted that even though the theorical minimum sampling rate ƒ.sub.S_MIN is uncertain, a possible value of the theorical minimum sampling rate ƒ.sub.S_MIN can be estimated according to the design and purpose of the wireless receiver 100; accordingly, the low sampling rate ADC 130 can use the sampling rate(s) ƒ.sub.S lower than the possible value to reduce the power consumption of the wireless receiver 100.

[0019] On the basis of the above description, the low sampling rate ADC 130 is allowed to sample the received signal S.sub.RX at a sampling rate ƒ.sub.S lower than the theorical minimum sampling rate ƒ.sub.S_MIN; however, this sampling rate ƒ.sub.S should be determined conditionally rather than arbitrarily. To be more specific, if the low sampling rate ADC 130 samples the received signal S.sub.RX at an inadequate sampling rate

[00001]$\left(\text{e}\text{.g}\text{.,}\frac{f_{S\text{\_}MIN}}{2}\right)$

lower than the theorical minimum sampling rate ƒ.sub.S_MIN, the low sampling rate ADC 130 will generate incomplete sampling results S.sub.SPL incapable of representing the received signal S.sub.RX; as a result, the power measurement circuit 140 cannot measure the power of the received signal S.sub.RX correctly. For example, FIG. 2 shows a first group of incomplete sampling results of the received signal S.sub.RX and a second group of incomplete sampling results of the received signal S.sub.RX. As shown in FIG. 2, the received signal S.sub.RX is a periodic signal (as illustrated with the dashed box in FIG. 2) and can be represented by four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4, wherein the height of each sampling result is linearly/nonlinearly proportional to the power of this sampling result. The first group of incomplete sampling results is obtained according to a sampling rate

[00002]$\frac{f_{S\text{\_}MIN}}{2}$

and only includes the first sampling result S.sub.1 and the third sampling result S.sub.3 of the four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4; since the average power of the two sampling results S.sub.1 and S.sub.3 is higher than the average power of the four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4, an average power of the received signal S.sub.RX measured by the power measurement circuit 140 according to the first group of incomplete sampling results is higher than the actual average power of the received signal S.sub.RX. The second group of incomplete sampling results is obtained according to a different starting sampling point but the same sampling rate

[00003]$\frac{f_{S\text{\_}MIN}}{2},$

and only includes the second sampling result S.sub.2 and the fourth sampling result S.sub.4 of the four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4; since the average power of the two sampling results S.sub.2 and S.sub.4 is lower than the average power of the four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4, an average power of the received signal S.sub.RX measured by the power measurement circuit 140 according to the second group of incomplete sampling results is lower than the actual average power of the received signal S.sub.RX. In consideration of the above, although the first/second group of incomplete sampling results is obtained according to a sampling rate

[00004]$\frac{f_{S\text{\_}MIN}}{2}$

lower than the theorical minimum sampling rate ƒ.sub.S_MIN, each of the first and second groups of incomplete sampling results cannot fully represent the received signal S.sub.RX.

[0020] In light of the above, the sampling rate ƒ.sub.S of the low sampling rate ADC 130 should be lower than the theorical minimum sampling rate fs ƒ.sub.S_MIN to reduce the power consumption of the wireless receiver 100, and should be determined adequately as mentioned in the following paragraphs to ensure that the low sampling rate ADC 130 generates adequate sampling results S.sub.SPL of the received signal S.sub.RX.

[0021] FIG. 3 shows an embodiment of the method of the present disclosure for measuring the power of a received signal. This embodiment can be performed by the wireless receiver 100 of FIG. 1 or the equivalent thereof, and it is applicable to a circumstance that the signal cycle of the received signal can be ascertained. The embodiment includes the following steps:

[0022] S310: determining N type(s) of sampling rate(s) of an ADC (e.g., the low sampling rate ADC 130 in FIG. 1) according to a theoretical minimum sampling rate (e.g., the aforementioned ƒ.sub.S_MIN) of the received signal, wherein the theoretical minimum sampling rate corresponds to the signal cycle of the received signal, the N is a positive integer, the N type(s) of sampling rate(s) correspond(s) to N type(s) of sampling cycle(s), and the signal cycle (i.e., a product of a signal-cycle coefficient and a unit of time) and each of the N type(s) of sampling cycle(s) (i.e., a product of a sampling-cycle coefficient and the unit of time, wherein the sampling-cycle coefficient varies with the type of sampling cycle) are coprime (i.e., the signal-cycle coefficient and the sampling-cycle coefficient are coprime). For example, when the N is one, the signal cycle is T.sub.S, and the sampling cycle is T.sub.1, the signal cycle T.sub.S (i.e., α × ΔT, wherein α is a signal-cycle coefficient and ΔT is a unit of time) and the sampling cycle T.sub.1 (i.e., β × ΔT, wherein β is a sampling-cycle coefficient and ΔT is the unit of time) are coprime (i.e., α and β are coprime). For example, when the N is greater than one, the signal cycle is T.sub.S, and the N types of sampling cycles are T.sub.1, T.sub.2, ..., and T.sub.N, the signal cycle T.sub.S and each of the N types of sampling cycles T.sub.1, T.sub.2, ..., and T.sub.N are coprime.

[0023] S320: obtaining sampling results from the ADC sampling the received signal according to the N type(s) of sampling rate(s) within a period of sampling time. To be more specific, the ADC obtains one or more sampling result(s) according to each sampling rate within the period of sampling time, and thereby the ADC obtains the sampling results according to all sampling rate(s) (i.e., the N type(s) of sampling rate(s)). For example, the N type(s) of sampling rate(s) correspond(s) to N type(s) of sampling cycle(s); when the N is one, the N type(s) of sampling cycle(s) is a certain sampling cycle, and the total number of the sampling results is not less than the numerical value of the certain sampling cycle. For example, the N type(s) of sampling rate(s) correspond(s) to N type(s) of sampling cycle(s); when the N is greater than one, the total number of the sampling results is not less than the numerical value of the maximum sampling cycle of the N types of sampling cycles. It is noted that the unit of each sampling cycle is centisecond/millisecond/microsecond or determined according to implementation needs.

[0024] S330: measuring the power of the received signal according to the sampling results and the period of sampling time. For example, the step S330 includes: calculating and adding up power according to the sampling results and thereby obtaining total power; and dividing the total power by the period of sampling time and thereby obtaining average power as the power of the received signal.

[0025] FIG. 4 shows the sampling results obtained with the method of FIG. 3. In regard to the embodiment of FIG. 3, the theoretical minimum sampling rate of the received signal is ƒ.sub.S_MIN, the signal cycle of the received signal is

[00005]$\frac{1}{f_{S\text{\_}MIN}}=T_S,$

the ADC mentioned in the step S310 samples the received signal according to a single sampling rate

[00006]$\frac{f_{S\text{\_}MIN}}{3},$

and the corresponding sampling cycle is

[00007]$\frac{3}{f_{S\text{\_}MIN}}=K\times T_S=3T_S.$

The received signal is periodic (as illustrated with the dashed box in FIG. 4) and can be represented by four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4 which repeat periodically. As shown in FIG. 4, the sampling results of the ADC includes the first sampling result S.sub.1, the fourth sampling result S.sub.4, the third sampling result S.sub.3, the second sampling result S.sub.2, and so on and so forth. Accordingly, the sampling results of the ADC include the four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4 and are sufficient to represent the received signal. As a result, the power measurement circuit 140 can correctly measure the power of the received signal according to the sampling results of the ADC. It is noted that the signal cycle T.sub.S (i.e., T.sub.S = 1 × ΔT, wherein 1 is the signal-cycle coefficient and ΔT is the unit of time) and the sampling cycle 3T.sub.S (i.e., 3T.sub.S = 3 × ΔT, wherein 3 is a sampling-cycle coefficient and ΔT is the unit of time) are coprime, which means that T.sub.S is not divisible by 3T.sub.S.

[0026] FIG. 5 shows another embodiment of the method of the present disclosure for measuring the power of a received signal. This embodiment can be performed by the wireless receiver 100 of FIG. 1 or the equivalent thereof, and it is applicable to a circumstance that the signal cycle of the received signal is uncertain or not required. The embodiment includes the following steps:

[0027] S510: using an ADC (e.g., the low sampling rate ADC 130 in FIG. 1) to sample the received signal according to multiple types of sampling rates within a period of sampling time and thereby obtaining sampling results, wherein the multiple types of sampling rates are corresponding to multiple types of sampling cycles (e.g., 3T.sub.S, 7T.sub.S, 11T.sub.S,...), and the multiple types of sampling cycles are coprime to one another. For example, the period of sampling time is not shorter than the maximum sampling cycle of the multiple types of sampling cycles. For example, the multiple types of sampling cycles are 2T.sub.S, 3T.sub.S, and 5T.sub.S, and the ADC sampled the received signal every 2T.sub.S, every 3T.sub.S, and every 5T.sub.S.

[0028] S520: measuring the power of the received signal according to the sampling results and the period of sampling time. This step is similar to the step S330.

[0029] FIG. 6 shows yet another embodiment of the method of the present disclosure for measuring the power of a received signal. This embodiment can be performed by the wireless receiver 100 of FIG. 1 or the equivalent thereof, and it is applicable to a circumstance that the signal cycle of the received signal is uncertain or not required. The embodiment includes the following steps:

[0030] S610: using an ADC (e.g., the low sampling rate ADC 130 in FIG. 1) to sample the received signal according to N types of sampling intervals (e.g., 2T, 3T, and 5T, wherein 2, 3, and 5 are coefficients, and T is a given unit of time) within a period of sampling time and thereby obtaining sampling results, wherein the N types of sampling intervals are randomly determined and the N is an integer greater than one. In an exemplary implementation, the total number of the sampling results is not less than the maximum value of the N types of sampling intervals. It is noted that the N types of sampling intervals can be determined in a pseudo-random manner or in a true-random manner. It is also noted that the ADC can be a known ADC or a self-developed ADC.

[0031] S620: measuring the power of the received signal according to the sampling results and the period of sampling time. This step is similar to the step S330.

[0032] FIG. 7 shows sampling results obtained with the method of FIG. 6. Regarding the embodiment of FIG. 6, the theoretical minimum sampling rate of the received signal is ƒ.sub.S_MIN, the signal cycle of the received signal is

[00008]$\frac{1}{f_{S\text{\_}MIN}}=T_S,$

and the ADC mentioned in the step S610 samples the received signal according to sampling intervals that are determined randomly. The received signal is periodic (as illustrated with the dashed box in FIG. 7) and can be recovered by at least four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4. As shown in FIG. 7, the sampling results of the ADC includes the first sampling result S.sub.1, the third sampling result S.sub.3, the second sampling result S.sub.2, the second sampling result S.sub.2, the fourth sampling result S.sub.4, the third sampling result S.sub.3, etc. Accordingly, the sampling results of the ADC include the four sampling results S.sub.1, S.sub.2, S.sub.3, and S.sub.4 and are sufficient to represent the received signal provided that the period of sampling time is long enough, that is to say that the N is great enough. As a result, the power measurement circuit 140 can correctly measure the power of the received signal according to the sampling results of the ADC.

[0033] It is noted that people having ordinary skill in the art can selectively use some or all of the features of any embodiment in this specification or selectively use some or all of the features of multiple embodiments in this specification to implement the present invention as long as such implementation is practicable; in other words, the way to implement the present invention can be flexible based on the present disclosure.

[0034] To sum up, the method of the present disclosure can measure the power of a received signal at an extraordinarily low sampling rate and thereby allow a wireless receiver using the method to reduce its power consumption.

[0035] The aforementioned descriptions represent merely the preferred embodiments of the present invention, without any intention to limit the scope of the present invention thereto. Various equivalent changes, alterations, or modifications based on the claims of the present invention are all consequently viewed as being embraced by the scope of the present invention.