Impacts of multipath fading on the timing synchronization of IEEE 802.11a wireless LANs

Based on the maximum-likelihood principle and the preamble structure of IEEE 802.11a WLAN standard, this paper proposes a new symbol synchronization algorithm for IEEE 802.11a WLANs over frequency-selective fading channels. In addition to the physical channel, the effects of filtering and unknown sampling phase offset are also considered. Loss in system performance due to synchronization error is used as a performance criterion. Computer simulations show that the proposed algorithm has comparable performances to the algorithm based on the generalized Akaike information criterion (GAIC), but the proposed algorithm exhibits reduced complexity.

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Design and implementation in USRP of a preamble-based synchronizer for OFDM systems

Herrera-Bustamante¹,

Rodríguez-Ludeña²,

Correa-Mena³

et al. 2020

2020 Ieee Andescon

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The Orthogonal Frequency Division Multiplexing (OFDM) is one of the most widely adopted schemes in wireless technologies such as Wi-Fi and LTE due to its high transmission rates, and the robustness against Intersymbol Interference (ISI). However, OFDM is highly sensitive to synchronism errors, which affects the orthogonality of the carriers. We analyzed several synchronization algorithms based on the correlation of the preamble symbols through the implementation in Software-Defined Radio (SDR) using the Universal Software Radio Peripheral (USRP). Such an implementation was performed in three stages: frame detection, comparing the autocorrelation output and the average power of the received signal; time synchronism, where the crosscorrelation based on the short and long preamble symbols was implemented; and the frequency synchronism, where the Carrier Frequency Offset (CFO) added by the channel was detected and corrected. The synchronizer performance was verified through the USRP implementation. The results serve as a practical guide to selecting the optimal synchronism scheme and show the versatility of the USRP to implement digital communication systems efficiently.

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Impacts of multipath fading on the timing synchronization of IEEE 802.11a wireless LANs

Cited by 17 publications

References 7 publications

Symbol Timing Synchronization Algorithms for Wireless LAN Systems in Multipath Channels

Symbol Timing Synchronization Algorithms for Wireless LAN Systems in Multipath Channels

ML symbol synchronization for OFDM-based WLANs in unknown frequency-selective fading channels

Design and implementation in USRP of a preamble-based synchronizer for OFDM systems

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