An improved linear dispersion codes transmission scheme based on OSIC detection

Linear dispersion codes (LDCs) were originally designed based on maximum likelihood detection. They do not have good performance when using ordered successive interference cancellation (OSIC) detection. In this paper,we propose a new improved linear dispersion codes transmission scheme to combat performance loss of original LDCs when using OSIC detection. We introduce an interleaver to each data substream transmitted over different antennas after LDCs encoder. Furthermore,a new computer search criterion for a linear transformation matrix is also proposed. New search criterion is to minimize the symbol error rate based on OSIC detection. Computer simulations show that the performance of proposed LDCs transmission scheme is better than the original LDCs.

AN IMPROVED AND EFFICIENT DETECTION SCHEME FOR V-BLAST SYSTEMS WITH QAM MODULATION

The paper proposed an improved Ordered Successive Interference Cancellation(OSIC) detection scheme for V-BLAST systems with square/rectangular Quadrature Amplitude Modulation(QAM) modulation.It utilizes an equivalent real-valued vector expression of relationship between transmit signals and received signals,exploits the constellation's product-form structure and can eventually make the order,in which components of the transmit signals vector are extracted,more "optimal" in some sense.Thereby,it can offer an improved error probability as compared to the conventional OSIC detection scheme.In addition,the paper also proposes an efficient projection al-gorithm to calculate nulling vectors in a simple recursive fashion in order to avoid the vast increase of complexity,which is due to the fact that the original complex N -dimensional data vector and M×N channel matrix are transformed into a real 2N -dimensional data vector and a real 2M ×2N channel matrix respectively.A scrutinous complexity analysis shows that the complexity increases by only 33% as compared to the conventional scheme.

SER bound for ordered ZF-SIC receiver in M-QAM MIMO system

With the advances of the 4th generation （4G） mobile communications targeting multi-user QoS-guaranteed multimedia services, multiple input multiple output （MIMO） combined with multi-level quadrature amplitude modulation （M-QAM） technique gains great popularity for its capability of supporting high data rate. In this article, the statistical distribution of signal to noise plus interference ratio （SINR） in each recursive step of optimal ordered zero-forcing perfect successive interference cancellation （ZF-OOPSIC） detection is deduced based on order statistics theory. The symbol error rate （SER） of M-QAM MIMO system with ZF-OOPSIC detector is analyzed under fiat Rayleigh fading channel. This precise analytical SER result could be taken as the lower bound of various zero-forcing ordered successive interference cancellation （ZF-OSIC） receivers. Combining the analytical SER expression for linear zero-forcing （ZF） receiver as upper bound, the rough range of SER for various ZF-OSIC detectors could be obtained. Monte Carlo （MC） simulations validate the analytical results and prove the conclusions.

Realization of Magnetic Signal Acquisition Scheme for Banknotes

In order to solve the problem of low signal-to-noise ratio（about 15 d B） in magnetic signal acquisition of banknotes, a new method of magnetic signal acquisition and processing is proposed taking RMB as an example. In this method, weak signa detection is performed to reduce the noise accompanied with the signal. Seven orders of Chebyshev（Ⅰ） filter and the anti-jamming technology are used in the PCB layout, and grounding modes are introduced to reduce the noise of the amplitude waveform. The proposed method reduce the final output noise by 2/3 and the sig nal-to-noise ratio is increased to 24 d B. The experimental results show that the magnetic signal of RMB banknotes are acquired by the circuit stability, which provides an important guarantee for the improvements of the anti-counterfeit and discrimination for banknotes performance.

Simplified MMSE Detectors for Turbo Receiver in BICM MIMO Systems

In this article, two methods adopting simplified minimum mean square error （MMSE） filter with soft parallel interference cancellation （SPIC） are discussed for turbo receivers in bit interleaved coded modulation （BICM） multiple-input multiple-output （MIMO） systems. The proposed methods are utilized in the non-first iterative process of turbo receiver to suppress residual interference and noise. By modeling the components of residual interference after SPIC plus the noise as uncorrelated Gaussian random variables, the matrix inverse for weighting vector of conventional MMSE becomes unnecessary. Thus the complexity can be greatly reduced with only slight performance deterioration. By introducing optimal ordering to SPIC, performance gap between simplified MMSE and conventional MMSE further narrows. Monte Carlo simulation results confirm that the proposed algorithms can achieve almost the same performance as the conventional MMSE SPIC in various MIMO configurations, but with much lower computational complexity.