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The concept of using unique word (UW) prefixes instead of cyclic prefixes (CPs) is already well investigated for single carrier systems with frequency domain equalization (SC/FDE). In OFDM (orthogonal frequency division multiplexing), where the data symbols are specified in frequency domain, the introduction of UWs - which are specified in time domain - is not that straight forward. In this paper...
FFH-OFDM combines fast frequency hopping (FFH) with regular OFDM symbols and it shows better performance in time-varying multi-path fading environments. This paper considers the precoding matrix and its receiver algorithm, simulation results show the difference. An implementation method of precoding in field programmable gate array (FPGA) is also discussed.
A differential cross-correlation cell ID identification algorithm is proposed for IEEE 802.16e OFDMA cellular system. First, we construct the downlink (DL) preamble structure and signal model with carrier frequency offset (CFO) and channel effects. Next, in order to achieve the initial synchronization, a differential receiver with cross correlation for all preamble patterns is proposed to search cell...
In OFDM systems, since carrier frequency offset (CFO) destroys the orthogonality among subcarriers, whose estimation/compensation is a critical problem. However, the CFO estimation suffers from DC offset (DCO) generated in low-cost direct-conversion receivers (DCRs). More seriously, in general, DCO is time-varying due to the automatic gain control. In this paper, we propose a novel CFO estimator in...
This paper analyzed the performance of a detection algorithm using MB-OFDM UWB receiver based on silent time when the victim signal is received by detection limit of -80 dBm/MHz proposed in Korea for DAA. Simulation results show that the performance of the proposed detection algorithm is enough to detect the victim signal with 95% detection probability within the +/-0.5 dB error range if repeat Number...
WiMAX is one of the most promising technologies for broadcast wireless communication and based on the IEEE 802.16 standards. The WiMAX networks support high speed transmission. But some hardware design, such as the IQ (inphase quadrature) imbalance due to direct conversion in RF front-end, limits their throughput. This problem is especially serious in high-order modulation. Most current papers of...
Effects of improved channel estimation are studied for a proposed IEEE 802.11n OFDM MIMO system. Three channel estimation methods are considered: maximum likelihood (ML), time-domain truncation (TDT) and model-based (MB). TDT and MB are particularly useful when the channel delay spread is short. For an MMSE receiver, MB shows a 1-2.5 dB improvement over ML on the packet error rate performance for...
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