CFR Results
Hardware Setup
Equipment used:
Agilent PSA spectrum analyzer.
Ubuntu PC equipped by LimeSDR-QPCIe board. Runs either Lime Suite GUI or real life BTS based on Amarisoft LTE stack, depending on test case scenario.
Windows 10 PC running Keysight Vector Signal Analyzer (VSA) software for modulation analyses.
In the test cases 1-4 the CFR algorithm is checked against 5MHz, 10MHz, 15MHz and 20MHz 64 QAM LTE modulated signals, with 20MHz being the most challenging one.
In test cases presented below, the signals are generated in different ways:
The waveforms are generated using the Test Model 3.1 (E-TM 3.1) test specification, which applies to most LTE modulation schemes. The test waveform is upload into WFM RAM block of LimeSDR-QPCIe board and played. One of the TX RF outputs is connected to PSA for the modulation analysis. In the reference point, the CFR block is bypassed. In the further measurement points, CFR block is enabled. Different CFR options are considered: CFR order L, threshold Th and interpolation.
Real BTS is constructed using Linux Ubuntu PC running Amarisoft LTE stack in FDD mode. This scenario checks the performance of Amarisoft LTE stack working together with LimeSDR-QPCIe hardware. Antennas are connected to LimeSDR-QPCIe RF ports. One of the TX outputs is connected to PSA via RF coupler. Data payload is generated by connecting mobile phone(s) to BTS and executing Magic Iperf application on both sides. The case when CFR is bypassed is used as the reference point for the final comparison. In the further measurement points, the CFR block is enabled.
Test Case 1: LTE 5MHz
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
10.38 |
0.91 |
-56.00 |
0.00 |
0.00 |
CFR |
21 |
0 |
0.75 |
8.12 |
2.18 |
-55.00 |
2.26 |
1.27 |
19 |
0 |
0.75 |
8.12 |
2.12 |
-55.00 |
2.26 |
1.21 |
|
17 |
0 |
0.75 |
8.20 |
2.05 |
-55.00 |
2.18 |
1.14 |
|
15 |
0 |
0.75 |
8.42 |
1.96 |
-55.00 |
1.96 |
1.05 |
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
10.62 |
0.61 |
-56.00 |
0.00 |
0.00 |
CFR |
21 |
0 |
0.66 |
8.48 |
2.06 |
-55.00 |
2.14 |
1.45 |
Test Case 2: LTE 10 MHz
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
10.38 |
0.98 |
-54.00 |
0.00 |
0.00 |
CFR |
19 |
0 |
0.75 |
8.28 |
2.28 |
-54.00 |
2.04 |
1.3 |
17 |
0 |
0.75 |
8.34 |
2.23 |
-54.00 |
1.98 |
1.25 |
|
15 |
0 |
0.75 |
8.38 |
2.19 |
-54.00 |
1.94 |
1.21 |
|
13 |
0 |
0.75 |
8.52 |
2.12 |
-54.00 |
1.80 |
1.14 |
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
10.74 |
0.55 |
-54.00 |
0.00 |
0.00 |
CFR |
17 |
0 |
0.66 |
8.42 |
2.30 |
-54.00 |
2.32 |
1.75 |
Test Case 3: LTE 15 MHz
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
10.54 |
1.03 |
-52.00 |
0.00 |
0.00 |
CFR |
19 |
1 |
0.75 |
8.34 |
2.22 |
-52.00 |
2.20 |
1.19 |
17 |
0 |
0.75 |
8.34 |
2.17 |
-52.00 |
2.20 |
1.14 |
|
15 |
0 |
0.75 |
8.48 |
2.11 |
-52.00 |
2.06 |
1.08 |
|
13 |
0 |
0.75 |
8.48 |
2.06 |
-52.00 |
2.06 |
1.03 |
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
10.94 |
0.62 |
-52.00 |
0.00 |
0.00 |
CFR |
17 |
0 |
0.66 |
8.44 |
2.19 |
-52.00 |
2.50 |
1.57 |
Test Case 4: LTE 20 MHz
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
10.54 |
1.15 |
-51.00 |
0.00 |
0.00 |
CFR |
17 |
1 |
0.75 |
8.24 |
2.33 |
-52.00 |
2.30 |
1.18 |
15 |
1 |
0.75 |
8.24 |
2.29 |
-52.00 |
2.30 |
1.14 |
|
13 |
0 |
0.75 |
8.24 |
2.22 |
-52.00 |
2.30 |
1.07 |
|
11 |
1 |
0.75 |
8.38 |
2.15 |
-52.00 |
2.16 |
1.00 |
CFR L |
CFR Int. |
CFR Th |
PAPR (dB) |
EVM (%) |
ACPR (dBc) |
° PAPR (dB) |
° EVM (%) |
|
|---|---|---|---|---|---|---|---|---|
No CFR |
/ |
/ |
/ |
11.20 |
0.60 |
-52.00 |
0.00 |
0.00 |
CFR |
13 |
1 |
0.66 |
8.42 |
2.30 |
-52.00 |
2.78 |
1.78 |