The effects of DC offset in direct-conversion receivers for WLAN systems

Abstract

In this paper, the effects DC offset in direct-conversion receivers for WLAN systems are analyzed using both experimental and simulation data. DC offset estimation is performed by using data-aided methods which are based on the short training sequence of WLAN preamble. In the simulations, DC offset and frequency offset estimations are carried out on the signals affected by frequency selective Rayleigh fading channel and additive white Gaussian noise. Estimation performance of the methods is compared for different SNR levels and frequency offset values in terms of mean square error. Experimental data which is in the form of WLAN packets and transmitted through a wireless channel is captured by using a software defined radio. The experimental performance of the DC offset compensation methods is evaluated in terms of transmission success ratio.

Keywords

• DC offset
• direct-conversion receivers
• frequency offset
• WLAN
• software defined radio

References

1. Bronckers, S., Roch, A., Smolders, B., Wireless receiver architectures towards 5G: Where are we?, IEEE Circuits Syst. Mag., 17 (3) (2017), 6-16, https://doi.org/10.1109/MCAS.2017.2713306.
2. Mirabbasi, S., Martin, K., Classical and modern receiver architectures, IEEE Commun. Mag., 38 (11) (2000), 132–139, https://doi.org/10.1109/35.883502.
3. Razavi, B., Design considerations for direct-conversion receivers, IEEE Trans. Circuits Syst. II: Analog Digit. Signal Process., 44 (6) (1997), 428–435, https://doi.org/10.1109/82.592569.
4. Abidi, A. A., Direct-conversion radio transceivers for digital communications, IEEE J. Solid-State Circuits, 30 (12) (1995), 186–187, https://doi.org/10.1109/4.482187.
5. Yih, C. -H., Analysis and compensation of DC offset in OFDM systems over frequency selective Rayleigh fading channels, IEEE Trans. Veh. Technol., 58 (7) (2009), 3436–3446, https://doi.org/10.1109/TVT.2009.2014240.
6. Xiangning, F., Yutao, S., Yangyang, F., A CMOS DC offset cancellation (DOC) circuit for PGA of low IF wireless receivers, 2010 International Symposium on Signals, Systems and Electronics, (2010), 1-4, https://doi.org/10.1109/ISSSE.2010.5607078.
7. Sohn, I. -H., Jeong, E. -R., Lee, Y. H., Data-aided approach to I/Q mismatch and DC offset compensation in communication receivers, IEEE Commun. Lett., 6 (12) (2002),547-549, https://doi.org/10.1109/LCOMM.2002.806451.
8. Tseng, H. -Y., Cho, W. -J., Chang, T. -K., Phoong, S. -M., Lin, Y. -P., Compensation of IQ Imbalance and DC Offset for OFDM Transmission over Frequency Selective Channels, 2008 IEEE International Conference on Communications, (2008), 641–645, https://doi.org/10.1109/ICC.2008.126.

9. Lin, H., Wang, X. and Yamashita, K., A Low-Complexity Carrier Frequency Offset Estimator Independent of DC Offset, IEEE Commun. Lett., 12 (7) (2008), 520-522, https://doi.org/10.1109/LCOMM.2008.080408.
10. Xia, Y., Ren, G., A high accuracy DC offset estimation scheme for OFDM based WLAN, 2011 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC), (2011), 1-4, https://doi.org/10.1109/ICSPCC.2011.6061726.
11. Marsili, S., DC offset estimation in OFDM based WLAN application, IEEE Global Telecommunications Conference, GLOBECOM'04., 6 (2004), 3531–3535, https://doi.org/10.1109/GLOCOM.2004.1379023.
12. IEEE Std. 802.11, IEEE Standard for Information technology-Telecommunications and information exchange between systems Local and metropolitan area networks-Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, 2016.
13. Lin, H., Sankassa, H. M., Senevirathna, B., Yamashita K., Blind Estimation of Carrier Frequency Offset and DC Offset for OFDM Systems, IEEE Trans. Commun., 56 (5) (2008), 704-707, https://doi.org/10.1109/TCOMM.2008.060215.
14. MathWorks, https://www.mathworks.com/help/wlan/, 2022.
15. Bar-Shalom, Y., Kirubarajan, T., Li, X. -R., Estimation with Applications to Tracking and Navigation, Wiley, New York, 2001.
16. MathWorks, https://www.mathworks.com/help//supportpkg/plutoradio/ug/transmission and-reception-of-an-image-using-wlan-system-toolbox-and-a-single-pluto-radio.html, 2022.