A single-carrier quasi-orthogonal distributed block space-time coding scheme for a wireless collaborative network with one relaying stage composed of four nodes is proposed. This block quasi-orthogonal design can atta...
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ISBN:
(纸本)9781617388767
A single-carrier quasi-orthogonal distributed block space-time coding scheme for a wireless collaborative network with one relaying stage composed of four nodes is proposed. This block quasi-orthogonal design can attain full diversity and maximum rate, and is based on simple amplify-and-forward processing at the relay nodes. A cyclic prefix is introduced into the block transmission to overcome channel delay mismatches in the paths through the four relays. In single-carrier operation, these delays are shown to introduce inter-symbol-interference (ISI) in the destination signal. A linear pre-processing scheme is therefore designed to mitigate this ISI through maximizing signal-to-interference-plus-noise ratio (SINR) at the receiver in combination with iterative equalization. To reduce the computational complexity of this scheme the underlying interference matrices are rendered sparse by the pre-processing operation. Simulation studies confirm the improvement in SINR of the proposed approach as compared to one which only uses rectangular pre-windowing.
space-time transmit diversity, as an effective scheme to mitigate multipath fading, has been proposed for IMT-2000 systems. space-time Transmit Diversity(STTD) has been adopted as an open loop diversi
space-time transmit diversity, as an effective scheme to mitigate multipath fading, has been proposed for IMT-2000 systems. space-time Transmit Diversity(STTD) has been adopted as an open loop diversi
In multi-antenna transmission systems, multiple parallel radio implementations are needed. To keep the overall transceiver implementation feasible, this poses big restrictions on the size and cost of individual radios...
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In multi-antenna transmission systems, multiple parallel radio implementations are needed. To keep the overall transceiver implementation feasible, this poses big restrictions on the size and cost of individual radios, resulting in various imperfections in the analog radio front-ends. One good example is the so-called I/Q imbalance problem related to the amplitude and phase matching of the transceivers I and Q chains. This paper considers this I/Q mismatch problem in space-time coded multi-antenna OFDM system context, taking both transmitter and receiver sides into account and assuming the challenging yet practical case of frequency-dependent I/Q mismatches. Practical pilot-based I/Q imbalance compensation scheme is proposed, stemming from the derived signal and system models and proper pilot allocation. The performance of the compensator is analyzed using extensive computer simulations and shown to virtually reach the perfectly matched reference system performance with low pilot overhead. Also some important practical issues such as pilot interpolation as well as the effects of channel estimation errors in the imbalance compensation context are addressed.
In this paper,we consider the spacetime spreading in forward links of the MC-DS-CDMA system when random signature sequences are *** performance of the system with different diversity order has also been *** numerical...
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In this paper,we consider the spacetime spreading in forward links of the MC-DS-CDMA system when random signature sequences are *** performance of the system with different diversity order has also been *** numerical results show that considerable performance gain can be obtained by transmit diversity when the active user number is relatively *** the number of the users increases, the diversity gain will *** also suggests that it require multiuser interference cancelation when the active user number is relatively large.
Gallager's bounding techniques are employed to derive tight upper bounds on the decoding error probability Of space-time codes in quasi-static Rayleigh fading channels. The bounds converge rapidly and are within a...
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Gallager's bounding techniques are employed to derive tight upper bounds on the decoding error probability Of space-time codes in quasi-static Rayleigh fading channels. The bounds converge rapidly and are within a few decibels from simulation results. Moreover, they permit efficient numerical computation, which represents a major advantage over the existing limit-before-average technique. Therefore, the proposed bounds are a meaningful and practical tool for performance analysis and computer search of good space-time codes.
In this paper, a simple subspace based semi-blind channel estimator is developed for precoded OFDM systems. This channel estimator relies on redundant linear precoding. With this proposed channel estimator, the channe...
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In this paper, a simple subspace based semi-blind channel estimator is developed for precoded OFDM systems. This channel estimator relies on redundant linear precoding. With this proposed channel estimator, the channel identifiability is guaranteed up to one scalar ambiguity, regardless of the channel zero locations and the underlying signal constellations. The ambiguity can be resolved with the known pilots inserted in the transmitted sequences. Computer simulations are conducted to support our analysis. The simulation results show that, compared with the well known LS estimator, the proposed estimator achieves higher estimation accuracy and is capable of tracking slow channel variations.
This paper presents a closed-form power allocation scheme for space-time coded multiple-antenna systems with imperfect channel state information at the transmitter. The proposed scheme is based on a so-called compress...
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ISBN:
(纸本)9781424442959
This paper presents a closed-form power allocation scheme for space-time coded multiple-antenna systems with imperfect channel state information at the transmitter. The proposed scheme is based on a so-called compressed signal-to-noise ratio (CSNR) criterion, where a single compression factor is used to minimize the bit-error-rate (BER). The obtained closed-form solution is computational efficient and achieves almost the same performance as the existing optimal approach which requires numerical search, and outperforms the existing suboptimal closed-form algorithm.
In this paper we analyze the performance of a general user cooperative space-time coded system in wireless network. The upper bound of the pairwise error probability (PEP) is derived, on slow, quasi-slow and fast fadi...
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In this paper we analyze the performance of a general user cooperative space-time coded system in wireless network. The upper bound of the pairwise error probability (PEP) is derived, on slow, quasi-slow and fast fading channels. From the upper bounds, we show that cooperative space-time coded system in wireless network can achieve full cooperation diversity gain and coding gain. Based on the performance analysis, we formulate a generalized space-time code design criteria to construct better codes for user cooperation systems.
D An OFDM system of concatenating Trellis coded modulation with space-time block coding is proposed. The analysis of pairwise error probability (PEP) shows that if TCM is properly designed the maximum
D An OFDM system of concatenating Trellis coded modulation with space-time block coding is proposed. The analysis of pairwise error probability (PEP) shows that if TCM is properly designed the maximum
In this paper,an image communication system isproposed over time-selective fading channels based onmulti-antennas and Kalman filter *** extend the Liu'smethod to 2-2 antennas and add the channel coding;comparedwit...
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In this paper,an image communication system isproposed over time-selective fading channels based onmulti-antennas and Kalman filter *** extend the Liu'smethod to 2-2 antennas and add the channel coding;comparedwith the case of no channel coding,the coding gain of the systemcan be improved about *** proposed scheme improves theperformance of the bit error rate(BER)of the system at lowersignal to noise ratios(SNR);when BER is about 1.E-4,and SNRmore than 3dB,the received image can be satisfied.
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