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The Fourth generation (4G) wireless networks are expected to afford high data rate transmission of multimedia services such as wireless video, wireless Internet access and mobile computing. Orthogonal frequency division multiplexing (OFDM) is an effective technique for the future 4G communications because of its great immunity to impulse noise and intersymbol interference. Ultra wide band (UWB) wireless...
A channel estimation approach yielding both channel gains and the number of multi-paths is presented. The algorithm is based on a variation of conditional model order estimation (CME), and is proposed for MIMO-OFDM systems. The CME based estimator is shown to be viable in both fixed and mobile broadband MIMO-OFDM wireless applications, and takes advantage of determining the nonzero taps as well. The...
This article researches the channel estimation algorithm based on multi-input multi-output & orthogonal frequency division multiplexing (MIMO-OFDM) system. It is mainly working on the research of channel estimation algorithm based on training sequence least square (LS) criterion. On the basis of introducing the LS time domain channel estimation algorithm, it brings about an improved LS time domain...
In this paper, an adaptive detection technique for MIMO-OFDM system is proposed. To execute the adaptive detection, existing SMLD technique is considered. The proposed technique selects proper values of V of the SMLD scheme to each subcarrier according to its estimated received power. To estimate the received power, two estimation modes are presented (noise value estimation mode with a preamble and...
Multiple input-multiple output (MIMO) systems hold the potential to drastically improve the spectral effciency and link reliability in future wireless communications systems. A particularly promising candidate for next-generation fixed and mobile wireless systems is the combination of MIMO with Orthogonal Frequency Division Multiplexing (OFDM). OFDM has become the standard method because of its advantages...
Some communication applications, like multimedia, deliver data of different importance classes allowing unequal error protection (UEP) levels. In this paper, a multiple-input multiple-output (MIMO) system using orthogonal frequency division multiplexing (OFDM) is considered with a new UEP bit-loading algorithm based on the non-UEP algorithm by Chow, Cioffi, and Bingham. In the proposed bit-loading...
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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