OXX B66 Rx sensitivity issue debug and Desense Analysis

1. OXX B66 Rx Sensitivity
Issue Debug
Jay Chang
1

2. 2
B66 channel number
B66_20MHz
RB ch.132072 ch.132322 ch.132572
1@0 -95.2 -94.8 -91.6
HB1 (iLNA)
1@49 -93.3 -92.6 -93.1
1@99 -95.1 -94.7 -90.7
100@0 -98.5 -98 -97.5
1@0 -97.4 -98.2 -96.6
MB4 (mLNA)
1@49 -94.4 -94.8 -94.6
1@99 -97.8 -97.8 -96.9
100@0 -99.4 -99.7 -99.4
2 port for testing (default matching) 阿娟的結果

3. 3
B66_20MHz
RB ch.132072 ch.132322 ch.132572
1@0 -95.2 -94.8 -91.6
HB1 (iLNA)
1@49 -93.3 -92.6 -93.1
1@99 -95.1 -94.7 -90.7
100@0 -98.5 -98 -97.5
1@0 -97.4 -98.2 -96.6
MB4 (mLNA)
1@49 -94.4 -94.8 -94.6
1@99 -97.8 -97.8 -96.9
100@0 -99.4 -99.7 -99.4
2 port for testing (default matching)

4. 4
B66_20MHz
RB ch.132072 ch.132322 ch.132572
1@0 -96.1 -95.7 -92.6
1@49 -94.2 -93.5 -94.1
1@99 -96.1 -95.7 -91.8
100@0 -98.9 -98.2 -98.3
• Default radio default matching only change in B66 Rx
SAW 3.5n(M)_SAW_3.5n(M)
• The corresponding PRx sensitivity as below (use 2 ports
for testing) (default matching)
Rx SAW的問題嗎 ?

5. 5
SAW filter for B66 Rx : frequency response
R1 = R2 = 50 Ohm
L1 = L2 = 3.6 nH

6. 6
SAW filter for B66 Rx Spec.

7. 7
SAW filter for B1/B4 Rx Spec.
R1 = R2 = 50 Ohm

8. 8
SAW filter for B1/B4 Rx: frequency response
R1 = R2 = 50 Ohm
Rx SAW的問題嗎 ?
嘿嘿!! 當然不是.

9. 9
根據阿娟的結果B66 PRx 2根 sensitivity由iLNA改接到mLNA為啥會有如此大的差異呢?
(大家都講 因為mLNA gain比iLNA gain大十幾dB, 53 - 38.7 =14.3, 降講合理嗎? 這樣講有甚麼盲點盲點盲點盲點呢…
我們直接算一下)
根據sensitivity [dBm] = -174 + 10log10(BWin Hz) + loss + RxNF + C/N
where loss = total loss before LNA., RxNF = receiver noise figure (ex: SDR660)
上面公式適用於沒有external LNA (eLNA).
那有eLNA公式變成怎樣呢
loss + RxNF 這兩項就合併成cascade NF了嘛!!
所以只要計算cascade NF就能得知有eLNA的sensitivity了.
B66_20MHz
RB ch.132072 ch.132322 ch.132572
1@0 -95.2 -94.8 -91.6
HB1 (iLNA)
1@49 -93.3 -92.6 -93.1
1@99 -95.1 -94.7 -90.7
100@0 -98.5 -98 -97.5
1@0 -97.4 -98.2 -96.6
MB4 (mLNA)
1@49 -94.4 -94.8 -94.6
1@99 -97.8 -97.8 -96.9
100@0 -99.4 -99.7 -99.4
2 port for testing (default matching) 阿娟的結果
計算一下linkbudget看有沒有調到極值…

10. 10
計算OXX_B66_PRx black diagram cascade NF如下
計算iLNA and mLNA 20MHz 單根 sensitivity
iLNA: -174 + 10log10(20MHz) + 6.3 + (-1) = -95.7
mLNA: -174 + 10log10(20MHz) + 5 + (-1) = -97
(如果要跟阿娟結果雙根比較, 自己再各加個2.5-3 dB進去)

11. 11
所以接到mLNA sensitivity 理論上會變好1.3 dB, 阿娟20M FRB的結果在計算預期內.
此次的驗證假設
Trace loss 估計0.8 dB.
所有元件insertion loss使用datasheet Typical的值 不考慮Worst case.
所有的mismatch loss沒有考慮進去 (都假設stage 1 2 3皆咩到50 Ohm, 再用靠近SDR的兩三顆轉到
SDR LNA NF min處) i.e. 算出來的sensitivity是極值.
所以再回過頭來看”mLNA gain比iLNA gain大十幾dB”, 這樣講顯然有盲點盲點盲點盲點
因為除非你要算cascade NF到stage 5, 不然NF公式是不會出現G4(就是mLNA gain or iLNA gain)的.
真要說應該說”iLNA NF (分子分子分子分子)太大太大太大太大, 使得使得使得使得eLNA gain已經很大了但已經很大了但已經很大了但已經很大了但(分母分母分母分母)稀釋不掉稀釋不掉稀釋不掉稀釋不掉, 造成造成造成造成cascade NF
變大變大變大變大, sensitivity變差變差變差變差”
なるほどですね !! 除了Rx沒調到極值外, 原來sensitivity跟iLNA NF和eLNA gain有著極大關係阿!!

12. 12
OXX

13. 13
20M 單根 B66 PRx
Bypass [eLNA+SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 4 + 2.3 + (-1) = -95.7
With [eLNA +SAW] + iLNA in SDR660
-174 + 10log10(20MHz) + 6.3 + (-1) = -95.7
With [eLNA +SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 5 + (-1) = -97
20M 單根 B66 DRx
Bypass [eLNA+SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 3.5 + 2.3 + (-1) = -96.2
With [eLNA +SAW] + iLNA in SDR660
-174 + 10log10(20MHz) + 5.82 + (-1) = -96.2
With [eLNA +SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 4.5 + (-1) = -97.5
接著比較各種topology的sensitivity…

14. 14
Bypass eLNA 接mLNA tuning B66 PRx matching 2種不同topology 任君比較
To mLNA
RAC142 RAC138 RAC143 RAL264 RAL125 channel 132072 132322 132572 20M FRB 單根單根單根單根
0.5p 22p 2.4p 0 Ohm 3n 95.1 95.3 95 Q = 1.65
0.5p 22p 5.6n 33p 1.2n 95.2 95.4 94.9 Q = 1.12
有L+C組合
也有L+L組合
順便附上Q值
怎麼選: 選Q越大, Q = f0/Δf, Δf越小, 窄帶濾波好 BUT 注意1RB@0 and 1RB@99會不會被砍掉, 所
以要trade off (RF最愛玩的槌豆腐 XD).
如果不行就選Q次大的.
Sensitivity = -174 + 10log10(20MHz) + 4 + 2.3 + (-1) = -95.7
實際去bypass eLNA, Rx切mLNA調到極值比較一下

15. 15
DRx調到極值比較一下

16. 16
接著我們來算一下大家長 Q社的ref. design B66 PRx and DRx

17. 17
PRx

18. 18
接著我們來算一下大家長 Q社的ref. design B66 PRx and DRx

19. 19
DRx

20. 20
20M 單根 B66 PRx
Bypass [eLNA+SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 4 + 2.3 + (-1) = -95.7
With [eLNA +SAW] + iLNA in SDR660
-174 + 10log10(20MHz) + 6.3 + (-1) = -95.7
With [eLNA +SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 5 + (-1) = -97
Q-ref Quadplexer + mLNA in SDR660
-174 + 10log10(20MHz) + 3.63 + 2.3 + (-1) = -96
20M 單根 B66 DRx
Bypass [eLNA+SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 3.5 + 2.3 + (-1) = -96.2
With [eLNA +SAW] + iLNA in SDR660
-174 + 10log10(20MHz) + 5.82 + (-1) = -96.2
With [eLNA +SAW] + mLNA in SDR660
-174 + 10log10(20MHz) + 4.5 + (-1) = -97.5
Q-ref Quadplexer + QLN + iLNA in SDR660
-174 + 10log10(20MHz) + 4.9 + (-1) = -97.1 接著比較各種topology的sensitivity…

21. 21
なるほどですね !! 除了Rx沒調到極值外, 原來sensitivity跟iLNA NF和eLNA gain有著極大關係阿!!
接著看一下eLNA spec

22. 22
I社 eLNA

23. 23
Q社 eLNA

24. 24
Q社 eLNA

25. 25
OXX B66 Desense Analysis

26. 26
OXX B66 PRx sensitivity analysis
LTE B66 ANT0 Coupler Diplexer ASM Quadplexer e-LNA NF Rx SAW
Trace +
mismatch loss
Loss before LNA Rx NF Rx BW CN Sensitivity
Typ 0 0.2 0.42 0.98 1.7 0.8 0.8 4.9 2.3 10 -1 -100.10
Worst 0.1 0.2 0.6 1.05 2.8 1.2 1 6.95 3 10 -1 -98.05
Rx
SAW

27. 27
Calculate OXX B66 PRx desense Tx leakage in Rx band
sensitivity = equivalent noise floor @ the LNA input due to thermal noise and Tx noise in Rx band +
10 × log(BW) + NF + C/N + IL_FE.
The equivalent noise floor @ the LNA input due to thermal noise and Tx noise in Rx band is the
power sum of the thermal noise floor and Tx noise in Rx band.
Thermal noise floor @ the LNA input is about -174 dBm/Hz.
Tx noise in Rx band @ the LNA input = Σ(WTR RxBN + PA RxB gain, PA RxBN) - DPx TRx isolation at Rx
frequency.
NF is the WTR noise figure.
C/N is the required SNR for demodulation.
IL_FEis the RF front-end IL.
LTE B66 ANT0 Coupler Diplexer ASM Quadplexer e-LNA NF Rx SAW
Trace +
mismatch loss
Loss before LNA Rx NF Rx BW CN Sensitivity
Typ 0 0.2 0.42 0.98 1.7 0.8 0.8 4.9 2.3 10 -1 -100.10
Worst 0.1 0.2 0.6 1.05 2.8 1.2 1 6.95 3 10 -1 -98.05

28. 28
DONE
T W T W T W T W T W T W T W T W T W T W T W T W T W
B1 2110–2170 10 54 54 -150 -150 -136 -136 29 32.5 59 52 54 50 -167.15 -165.20 -120.86 -117.44 4.55 5.80 -170.31 -161.64 -165.44 -160.05 -96.44 -91.05 -1.71 -5.15
B2 1930–1990 10 54 54 -148 -148 -133 -133 30.5 34 66.8 55 65.6 55 -169.09 -166.80 -117.38 -113.95 4.91 7.20 -178.07 -161.75 -168.57 -160.57 -99.57 -91.57 -0.52 -6.23
B3 1805–1880 10 54 54 -148 -148 -135 -135 29.5 33 56 52 56 50 -166.75 -164.40 -118.40 -114.96 4.95 6.60 -169.45 -158.36 -164.88 -157.39 -95.88 -88.39 -1.87 -7.01
B66 2110–2200 10 54 54 -150 -150 -138 -138 28 31.5 63.5 55 63.5 55 -169.10 -167.05 -121.89 -118.45 4.90 6.95 -180.49 -166.50 -168.80 -163.76 -99.80 -94.76 -0.30 -3.29
B12 729–746 10 54 54 -151 -151 -120 -120 27 30.5 63 60 58 55 -169.23 -167.55 -118.54 -117.23 4.77 6.45 -171.77 -165.78 -167.31 -163.57 -98.31 -94.57 -1.92 -3.98
Noise floor at
antenna
with RXBN
(dBm/Hz)
Sensitivity with
RXBN
(max Tx
power)(dBm)
Desense due
to
RXBN (dB)
RXBN due to Tx
at antenna
(dBm/Hz)
Desense due to Rx band noise of Tx leakage calculation
Band
Rx
frequency
(MHz)
BW (MHz)
SDR IP2
(dBm)
SDR RBN
(dBm/Hz)
PA RBN
(dBm/Hz)
PA Rx band
gain (dB)
DPx Tx-Rx
isolation
at Tx
frequency
(dB)
DPx Tx-Rx
isolation
at Rx
frequency
(dB)
Noise floor
(dBm/Hz) at
antenna
connector
without Tx noise
Total RXBN
at PA output
(dBm/Hz)
Loss from
Rx DPx
to antenna
(dB)
OXX B66 PRx desense analysis Tx leakage in Rx band
Rx
SAW

29. 29
Calculate OXX B66 PRx desense Tx IP2 noise
Sensitivity = equivalent noise floor @ the LNA input due to thermal noise and Tx leakage IP2 noise
(IM2) + 10 × log(BW) + NF + C/N + IL_FE.
The equivalent noise floor @ the LNA input due to thermal noise and IM2 is the power sum of the
thermal noise floor and Tx leakage IP2 noise.
Thermal noise floor @ the LNA input is about -174 dBm/Hz.
IM2 @ the LNA input = 2 × (Tx level @ the DPx Tx input - DPx TRx isolation @ Tx frequency) - WTR Rx
IP2 - the correction factor.
NF is the WTR noise figure.
C/N is the required SNR for demodulation.
IL_FEis the total RF front-end IL.
LTE B66 ANT0 Coupler Diplexer ASM Quadplexer e-LNA NF Rx SAW
Trace +
mismatch loss
Loss before LNA Rx NF Rx BW CN Sensitivity
Typ 0 0.2 0.42 0.98 1.7 0.8 0.8 4.9 2.3 10 -1 -100.10
Worst 0.1 0.2 0.6 1.05 2.8 1.2 1 6.95 3 10 -1 -98.05

30. 30
OXX B66 PRx desense analysis Tx IP2 noise
DONE
T W T W T W T W T W T W T W T W T W T W T W T W T W
B1 2110–2170 10 54 54 -150 -150 -136 -136 29 32.5 59 52 54 50 -167.15 -165.20 -31.58 -22.50 -198.16 -180.00 -193.61 -174.20 -167.14 -164.69 -98.14 -95.69 -0.01 -0.51
B2 1930–1990 10 54 54 -148 -148 -133 -133 30.5 34 66.8 55 65.6 55 -169.09 -166.80 -39.97 -26.10 -214.94 -187.20 -210.03 -180.00 -169.09 -166.60 -100.09 -97.60 0.00 -0.20
B3 1805–1880 10 54 54 -148 -148 -135 -135 29.5 33 56 52 56 50 -166.75 -164.40 -28.63 -22.10 -192.26 -179.20 -187.31 -172.60 -166.71 -163.79 -97.71 -94.79 -0.04 -0.61
B66 2110–2200 10 54 54 -150 -150 -138 -138 28 31.5 63.5 55 63.5 55 -169.10 -167.05 -36.30 -25.55 -207.60 -186.10 -202.70 -179.15 -169.10 -166.79 -100.10 -97.79 0.00 -0.26
B12 729–746 10 54 54 -151 -151 -120 -120 27 30.5 63 60 58 55 -169.23 -167.55 -36.23 -31.75 -207.46 -198.50 -202.69 -192.05 -169.23 -167.53 -100.23 -98.53 0.00 -0.02
Desense due to IP2 noise of Tx leakage calculation
Band
Rx
frequency
(MHz)
BW (MHz)
SDR IP2
(dBm)
SDR RBN
(dBm/Hz)
PA RBN
(dBm/Hz)
PA Rx band
gain (dB)
DPx Tx-Rx
isolation
at Tx
frequency
(dB)
DPx Tx-Rx
isolation
at Rx
frequency
(dB)
Noise floor
(dBm/Hz) at
antenna
connector
without Tx noise
Tx leakage power
at LNA (dBm)
IP2 noise
at LNA in
(dBm/Hz)
IP2 noise
at antenna
(dBm/Hz)
Noise floor at
antenna
with IP2 noise
(dBm/Hz)
Sensitivity with
IP2
(max Tx
power)(dBm)
Desense due
to IP2 (dB)
Rx
SAW

31. 31
DONE
T W T W T W T W T W T W T W T W T W T W T W T W T W
B1 2110–2170 10 54 54 -150 -150 -136 -136 29 32.5 59 52 54 50 -167.15 -165.20 -120.86 -117.44 4.55 5.80 -170.31 -161.64 -165.44 -160.05 -96.44 -91.05 -1.71 -5.15
B2 1930–1990 10 54 54 -148 -148 -133 -133 30.5 34 66.8 55 65.6 55 -169.09 -166.80 -117.38 -113.95 4.91 7.20 -178.07 -161.75 -168.57 -160.57 -99.57 -91.57 -0.52 -6.23
B3 1805–1880 10 54 54 -148 -148 -135 -135 29.5 33 56 52 56 50 -166.75 -164.40 -118.40 -114.96 4.95 6.60 -169.45 -158.36 -164.88 -157.39 -95.88 -88.39 -1.87 -7.01
B66 2110–2200 10 54 54 -150 -150 -138 -138 28 31.5 63.5 55 63.5 55 -169.10 -167.05 -121.89 -118.45 4.90 6.95 -180.49 -166.50 -168.80 -163.76 -99.80 -94.76 -0.30 -3.29
B12 729–746 10 54 54 -151 -151 -120 -120 27 30.5 63 60 58 55 -169.23 -167.55 -118.54 -117.23 4.77 6.45 -171.77 -165.78 -167.31 -163.57 -98.31 -94.57 -1.92 -3.98
Noise floor at
antenna
with RXBN
(dBm/Hz)
Sensitivity with
RXBN
(max Tx
power)(dBm)
Desense due
to
RXBN (dB)
RXBN due to Tx
at antenna
(dBm/Hz)
Desense due to Rx band noise of Tx leakage calculation
Band
Rx
frequency
(MHz)
BW (MHz)
SDR IP2
(dBm)
SDR RBN
(dBm/Hz)
PA RBN
(dBm/Hz)
PA Rx band
gain (dB)
DPx Tx-Rx
isolation
at Tx
frequency
(dB)
DPx Tx-Rx
isolation
at Rx
frequency
(dB)
Noise floor
(dBm/Hz) at
antenna
connector
without Tx noise
Total RXBN
at PA output
(dBm/Hz)
Loss from
Rx DPx
to antenna
(dB)
Conclusion: OXX B66 PRx desense analysis Tx leakage in Rx band
Rx
SAW

32. 32
Conclusion: OXX B66 PRx desense analysis Tx IP2 noise
DONE
T W T W T W T W T W T W T W T W T W T W T W T W T W
B1 2110–2170 10 54 54 -150 -150 -136 -136 29 32.5 59 52 54 50 -167.15 -165.20 -31.58 -22.50 -198.16 -180.00 -193.61 -174.20 -167.14 -164.69 -98.14 -95.69 -0.01 -0.51
B2 1930–1990 10 54 54 -148 -148 -133 -133 30.5 34 66.8 55 65.6 55 -169.09 -166.80 -39.97 -26.10 -214.94 -187.20 -210.03 -180.00 -169.09 -166.60 -100.09 -97.60 0.00 -0.20
B3 1805–1880 10 54 54 -148 -148 -135 -135 29.5 33 56 52 56 50 -166.75 -164.40 -28.63 -22.10 -192.26 -179.20 -187.31 -172.60 -166.71 -163.79 -97.71 -94.79 -0.04 -0.61
B66 2110–2200 10 54 54 -150 -150 -138 -138 28 31.5 63.5 55 63.5 55 -169.10 -167.05 -36.30 -25.55 -207.60 -186.10 -202.70 -179.15 -169.10 -166.79 -100.10 -97.79 0.00 -0.26
B12 729–746 10 54 54 -151 -151 -120 -120 27 30.5 63 60 58 55 -169.23 -167.55 -36.23 -31.75 -207.46 -198.50 -202.69 -192.05 -169.23 -167.53 -100.23 -98.53 0.00 -0.02
Desense due to IP2 noise of Tx leakage calculation
Band
Rx
frequency
(MHz)
BW (MHz)
SDR IP2
(dBm)
SDR RBN
(dBm/Hz)
PA RBN
(dBm/Hz)
PA Rx band
gain (dB)
DPx Tx-Rx
isolation
at Tx
frequency
(dB)
DPx Tx-Rx
isolation
at Rx
frequency
(dB)
Noise floor
(dBm/Hz) at
antenna
connector
without Tx noise
Tx leakage power
at LNA (dBm)
IP2 noise
at LNA in
(dBm/Hz)
IP2 noise
at antenna
(dBm/Hz)
Noise floor at
antenna
with IP2 noise
(dBm/Hz)
Sensitivity with
IP2
(max Tx
power)(dBm)
Desense due
to IP2 (dB)
Rx
SAW

33. 33
B12 Tx 3rd harmonic
ANT-Tx att = 35~43 dB
B12 Tx 3f0 = -30~-24 dBm
att = 35 dB
FE loss = 5 dB
-99.97 dBm/Hz – 43 – 35 + 5 = -173 dBm/Hz
B12
TRx
B66
DRx
-100 dBm/Hz
-121.9 dBm/Hz
OXX B12+B66 CA desense analysis
Rx
SAW
ANT-ANT iso = 10~15 dB

34. 34