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In telecommunications, the term cyclic prefix refers to the prefixing of a symbol with a repetition of the end. The receiver is typically configured to discard the cyclic prefix samples, but the cyclic prefix serves two purposes: It provides a guard interval to eliminate intersymbol interference from the previous symbol.
In wireless communication, the term numerology refers to "waveform parametrization, e.g., cyclic prefix, subcarrier spacing." [1] The waveform selection is subject to a set of real-world restrictions, so a practical mobile communication system (with signal propagation conditions that tend to vary significantly from one location to another), utilizes a set of different waveforms, or "multiple ...
American wireless carrier Nextel Communications field tested wireless broadband network technologies including Flash-OFDM in 2005. [53] Sprint purchased the carrier in 2006 and decided to deploy the mobile version of WiMAX, which is based on Scalable Orthogonal Frequency-Division Multiple Access (SOFDMA) technology. [54]
After removing the cyclic prefix at the receiver, a DFT is applied to arrive in the frequency domain, where a simple single-carrier frequency-domain-equalization (SC-FDE) scheme can be employed, followed by the IDFT operation. DFT: Discrete Fourier Transform; IDFT: Inverse Discrete Fourier Transform; CP: Cyclic Prefix; PS: Pulse Shaping
In OFDM, the beginning of each symbol is preceded by a guard interval.As long as the echoes fall within this interval, they will not affect the receiver's ability to safely decode the actual data, as data is only interpreted outside the guard interval.
In wireless communications, sequences are usually chosen for their spectral properties and for low cross correlation with other sequences likely to interfere. In the 802.11 standard, an 11-chip Barker sequence is used for the 1 and 2 Mbit/s rates.
DECT-2020 is compliant with the requirements for Ultra Reliable Low Latency Communications URLLC and massive Machine Type Communication (mMTC) of IMT-2020. DECT-2020 NR has new capabilities [44] compared to DECT and DECT Evolution: Better multipath operation (OFDM Cyclic Prefix) Better radio sensitivity (OFDM and Turbocodes)
But in long-range Wi-Fi, special technologies are used to get the most out of a Wi-Fi connection. The 802.11-2007 standard adds 10 MHz and 5 MHz OFDM modes to the 802.11a standard, and extend the time of cyclic prefix protection from 0.8 μs to 3.2 μs, quadrupling the multipath distortion protection. Some commonly available 802.11a/g chipsets ...