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The mobile WiMAX standard (802.16e) uses multiple-input multiple-output (MIMO) limited feedback linear precoding to exploit the channel state information at the transmitter. Although the performance of limited feedback linear precoding in relation to traditional open-loop MIMO-OFDM has been extensively studied in the literature, these studies commonly assume perfect channel estimation at the receiver...
In this paper, we consider a 2-hop downlink point-to-multipoint fixed relay systems and propose a novel linear processing strategy at the base station and relay station to improve the reliability of the source-relay and relay-to-destination links. When coupled with a soft-decode-and-forward protocol, the proposed scheme leads to significant performance gain compared to the conventionl solutions for...
3GPP LTE is the evolution of UMTS which will make possible to deliver next generation high quality multimedia services according to the users' expectations. The flexibility of the downlink OFDM radio interface with Adaptive Modulation and Coding (AMC), MIMO and H-ARQ plays a crucial role in achieving the low latency and high spectral efficiency promised by the new radio access standard. This paper...
Channel estimation of coded multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) in fast time-varying channels are considered. Maintaining high performance with manageable complexity relies on iterative soft-in soft-out equalization and decoding. Conventional frequency domain channel estimation methods have an irreducible error floor due to unaccounted intercarrier...
According to BPSK + STBC and QPSK + STBC (space-time block codes) wireless transmission system of two launch antenna and one or two receiving antenna, 8PSK+STBC high-speed wireless transmission system is proposed first in the research, and the transmission scheme is compared and simulated with Monte Carlo simulation from two aspects of noise performance and spectrum efficiency. The research results...
In mobile WiMAX systems, uplink collaborative MIMO (multiple input multiple output) performs spatial multiplexing with two PSSs (portable subscriber stations), each with one antenna. As two PSSs transmit collaboratively on the same sub-channel, the overall uplink capacity will be doubled. To perform this interesting technique with high performance, most system venders demand the optimal MLD (maximum-likelihood...
In mobile WiMAX systems, uplink collaborative MIMO (Multiple Input Multiple Output) performs spatial multiplexing with two MSs (Mobile Stations), each with one antenna. As two MSs transmit collaboratively on the same subchannel region, the overall uplink capacity will be doubled. To perform this interesting technique with high performance, most system venders demand the optimal MLD (Maximum-Likelihood...
The decision-directed space-alternating generalized expectation-maximization (SAGE) algorithm is introduced in [1] to estimate the channel and track the channel varying for OFDM systems with transmitter diversity. However, this method is based upon a discrete Fourier transform (DFT), which will cause power leakage and result in an error floor in a multipath channel with non-sample-spaced time delays...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H), which is required to operate under high mobility conditions resulting in significant Inter-carrier Interference (ICI). To mitigate ICI, several cancellation schemes have been proposed but they require reliable channel information at the receiver which is quite challenging...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H) which is required to operate under high mobility conditions resulting in significant Inter-Carrier Interference (ICI). Under these conditions, the conventional one-tap per subcarrier channel estimation and equalization is suboptimal since it does not account for ICI...
Correlative minimum shift keying (MSK), a second order polynomial modulation scheme known as tamed frequency modulation (TFM), is a constant envelope type of modulation with a perfect peak to average power ratio (PAPR), besides the property of low out of band power. We apply the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept. We then obtain a...
This paper studies efficient complex valued matrix manipulations for multi-user STBC-MIMO decoding. A novel method called Alamouti blockwise analytical matrix inversion (ABAMI) is proposed for the inversion of large complex matrices that are based on Alamouti sub-blocks. Another method using a variant of Givens rotation is proposed for fast QR decomposition of this kind of matrices. Our solutions...
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