DPD temperature compensation method

Abstract

The invention discloses a DPD (Digital Pre-Distortion) temperature compensation method. The method comprises the following steps: S1, generating a temperature compensation coefficient offline; and S2, performing temperature compensation on a DPD result by using the temperature compensation coefficient online. According to the invention, the DPD compensation value can be corrected according to the temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of communication signals, and in particular to a DPD temperature compensation method. Background Art

[0002] Affected by the non-ideal temperature characteristics of RF devices such as PA, the DPD compensation value changes with temperature. Therefore, the DPD compensation value needs to be corrected according to the temperature.

[0003] Therefore, a DPD temperature compensation method is proposed. Summary of the invention

[0004] The object of the present invention is to provide a DPD temperature compensation method.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A DPD temperature compensation method proposed by the present invention comprises the following steps:

[0007] S1, generate temperature compensation coefficient offline;

[0008] S2. Use the temperature compensation coefficient online to perform temperature compensation on the DPD result.

[0009] Preferably, the specific steps of step S1 are as follows:

[0010] S1.1. Obtain two sets of DPD compensation curves at different temperatures T1 and T2, where the input signal amplitude is recorded as X and AM-AM is recorded as AM-PM is recorded as

[0011] X=[x1,x2,…,x N ]

[0012]

[0013] S1.2. Offline calculation of the temperature measurement compensation curve of the AM-AM curve is AmComp, and the temperature measurement compensation curve of the AM-PM curve is PmComp.

[0014]

[0015] PmComp=[d1-b1,d2-b2,…,d N -b N ];

[0016] S1.3. According to the AmComp curve, select 3 points X A1 , X A2 , X A3 ∈X, and x1≤XA1 ≤X A2 ≤X A3 ≤x N To generate an approximate quadratic interpolation curve, X A1 , X A2 , X A3 The corresponding value is AmComp A1 , AmComp A2 , AmComp A3 , let the generated quadratic curve coefficients be α1, α2, α3 to satisfy:

[0017]

[0018] S1.4. According to the PmComp curve, select 3 points X P1 , X P2 , X P3 ∈X, and x1≤X P1 ≤X P2 ≤X P3 ≤x N To generate an approximate quadratic interpolation curve, X P1 , X P2 , X P3 The corresponding value is PmComp P1 ,PmComp P2 ,PmComp P3 , let the generated quadratic curve coefficients be β1, β2, β3 to satisfy:

[0019]

[0020] Preferably, the specific steps of step S2 are as follows:

[0021] S2.1, when the machine is powered on, obtain the current temperature T DPD DPD compensation curve under the condition of AM-AM is recorded as DPD AM , AM-PM is recorded as DPD PM

[0022] DPD AM =[a1, a2, a3, ..., a N ], DPD PM =[b1, b2, b3, ..., b N ];

[0023] S2.2, when the chip is working, send data Signal after DPD compensation

[0024]

[0025] S2.3, according to the current chip temperature TCur Further temperature compensation is performed on the DPD compensation result.

[0026] t AM =min(max(|D in |, X A1 ), X A3 )

[0027]

[0028] t PM =min(max(|D in |, X P1 ), X P3 )

[0029]

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention can correct the DPD compensation value according to the temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The PA AM-AM response curves of the same PA measured at two temperatures in the present invention;

[0033] Figure 2 Based on Figure 1 The PA response is calculated to obtain the DPD compensation curves at two temperatures;

[0034] Figure 3 This is a diagram showing the PA characteristic changes due to temperature during actual measurement of the present invention;

[0035] Figure 4 Temperature compensation curve obtained for DPD measurement;

[0036] Figure 5 It is the DPD temperature compensation quadratic interpolation curve;

[0037] Figure 6 This is the AM-AM response diagram from DPD input to PA output after DPD temperature compensation. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] A DPD temperature compensation method proposed by the present invention comprises the following steps:

[0040] 1. Generate temperature compensation coefficient offline

[0041] 1) Obtain two sets of DPD compensation curves at different temperatures T1 and T2, where the input signal amplitude is recorded as X and AM-AM is recorded as AM-PM is recorded as

[0042] X=[x1,x2,…,x N ]

[0043]

[0044] 2) The temperature measurement compensation curve for the offline calculation of the AM-AM curve is AmComp, and the temperature measurement compensation curve for the AM-PM curve is PmComp

[0045]

[0046] PmComp=[d1-b1,d2-b2,…,d N -b N ]

[0047] 3) According to the AmComp curve, select 3 points X A1 , X A2 , X A3 ∈X, and x1≤X A1 ≤X A2 ≤X A3 ≤x N To generate an approximate quadratic interpolation curve, X A1 , X A2 ,X A3 The corresponding value is AmComp A1 , AmComp A2 , AmCom pA3 , let the generated quadratic curve coefficients be α1, α2, α3 to satisfy

[0048]

[0049] 4) Similarly, according to the PmComp curve, select 3 points X P1 , X P2 , X P3 ∈X, and x1≤X P1 ≤X P2 ≤X P3 ≤x N To generate an approximate quadratic interpolation curve, X P1 , X P2, X P3 The corresponding value is PmComp P1 ,PmComp P2 ,PmComp P3 , let the generated quadratic curve coefficients be β1, β2, β3 to satisfy

[0050]

[0051] 2. Use the temperature compensation coefficient online to compensate the DPD results

[0052] 1) When the machine is powered on, obtain the current temperature T DPD DPD compensation curve under the condition of AM-AM is recorded as DPD AM , AM-PM is recorded as DPD PM

[0053] DPD AM =[a1, a2, a3, ..., a N ], DPD PM =[b1, b2, b3, ..., b N ]

[0054] 2) When the chip is working, it sends data Signal after DPD compensation

[0055]

[0056] 3) According to the current chip temperature T Cur Further temperature compensation is performed on the DPD compensation result.

[0057] t AM =min(max(|D in |, X A1 ), X A3 )

[0058]

[0059] t PM =min(max(|D in |, X P1 ), X P3 )

[0060]

[0061] Using the above steps to conduct experiments, the data are as follows:

[0062] Figure 1 This is the measured PA AM-AM response curve of the same PA at two temperatures, namely T1=35 degrees and T2=70.

[0063] Figure 2 is based on Figure 1 The PA response is calculated to obtain the DPD compensation curves at two temperatures, namely:

[0064] X=[x1,x2,…,x N ]yes Figure 2 The horizontal axis in and There are two curves in the figure.

[0065] Depend on Figure 2 It can be seen that due to the non-ideal temperature characteristics of PA, Figure 2 The DPD compensation curve changes with temperature.

[0066] Figure 3 The DPD and PA joint response is given when PA T1=35 and T2=70 degrees, using the DPD curve directly obtained with T1=35 (without temperature compensation).

[0067] Figure 3 It can be seen that due to the change in PA characteristics caused by temperature, when the DPD curve obtained using T1 = 35 degrees at T2 = 70 degrees, the DPD and PA joint response of the PA in the large signal part shows obvious nonlinearity.

[0068] Depend on Figure 3 The data shown can be obtained Figure 4 of

[0069] According to the AmComp curve, select 3 points And according to Figure 3 Set the corresponding AmComp A1 =--0.004,AmComp A2 =-0.045,AmComp A3 = 0, generates an approximate piecewise quadratic interpolation curve such as Figure 5 .

[0070] at last, Figure 6 The DPD curve obtained when T2 = 70 degrees using T1 = 35 degrees is given and Figure 5 After DPD temperature compensation, the AM-AM response from DPD input to PA output is shown in the figure. The linearity of the curve is obviously due to the lack of DPD temperature compensation. Figure 3 curve.

[0071] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0072] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for DPD temperature compensation, characterized in that: The following steps are involved: S1, generate temperature compensation coefficient offline; S2. Use the temperature compensation coefficient online to perform temperature compensation on the DPD result.

2. The DPD temperature compensation method according to claim 1, characterized in that: The specific steps of step S1 are as follows: S1.

1. Obtain two sets of DPD compensation curves at different temperatures T1 and T2, where the input signal amplitude is recorded as X and AM-AM is recorded as AM-PM is recorded as X=[x1,x2,…,x N ] S1.

2. Offline calculation of the temperature measurement compensation curve of the AM-AM curve is AmComp, and the temperature measurement compensation curve of the AM-PM curve is PmComp. PmComp=[d1-b1,d2-b2,...,d N -b N ]; S1.

3. According to the AmComp curve, select 3 points X A1 , X A2 , X A3 ∈X, and x1≤X A1 ≤X A2 ≤X A3 ≤x N To generate an approximate quadratic interpolation curve, X A1 , X A2 , X A3 The corresponding value is AmComp A1 , AmComp A2 , AmComp A3 , let the generated quadratic curve coefficients be α1, α2, α3 to satisfy: S1.

4. According to the PmComp curve, select 3 points X P1 , X P2 , X P3 ∈X, and x1≤X P1 ≤X P2 ≤X P3 ≤x N To generate an approximate quadratic interpolation curve, X P1 , X P2 , X P3 The corresponding value is PmComp P1 ,PmComp P2 ,PmComp P3 , let the generated quadratic curve coefficients be β1, β2, β3 to satisfy:

3. The DPD temperature compensation method according to claim 1, characterized in that: The specific steps of step S2 are as follows: S2.1, when the machine is powered on, obtain the current temperature T DPD DPD compensation curve under the condition of AM-AM is recorded as DPD AM , AM-PM is recorded as DPD PM <h2 style=";text-align:left;direction:ltr">DPD<h2 style=";text-align:left;direction:ltr"> AM <h2 style=";text-align:left;direction:ltr"> (a1, a2, a3,..., a)<h2 style=";text-align:left;direction:ltr"> N <h2 style=";text-align:left;direction:ltr"> ],DPD<h2 style=";text-align:left;direction:ltr"> PM <h2 style=";text-align:left;direction:ltr"> (b1, b2, b3,..., b)<h2 style=";text-align:left;direction:ltr"> N <h2 style=";text-align:left;direction:ltr"> ]; S2.2, when the chip is working, send data Signal after DPD compensation S2.3, according to the current chip temperature T Cur Further temperature compensation is performed on the DPD compensation result. t AM =min(max(|D in |,X A1 ),X A3 ) t PM =min(max(|D in |,X P1 ),X P3 )

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