Symbol Error Ratio Research Articles

Structured dispersion matrices from division algebra codes for space-time shift keying

We propose a novel method of constructing Dispersion Matrices (DM) for Coherent Space-Time Shift Keying (CSTSK) relying on arbitrary PSK signal sets by exploiting codes from division algebras. We show that classic codes from Cyclic Division Algebras (CDA) may be interpreted as DMs conceived for PSK signal sets. Hence various benefits of CDA codes such as their ability to achieve full diversity are inherited by CSTSK. We demonstrate that the proposed CDA based DMs are capable of achieving a lower symbol error ratio than the existing DMs generated using the capacity as their optimization objective function for both perfect and imperfect channel estimation.

Performance Analyses of the N–Rth Dual Best Relays Opportunistic Cooperation with Amplify-and-Forward Protocols

To overcome the loss in the outage probability and symbol error ratio (SER) caused by the Nth single relay opportunistic relaying (OR), in this paper, we present the N---Rth dual best relays OR sch...

16-QAM 신호에 대한 이중 구조 CR-CMA 적응 등화기의 성능

In this paper, the concerned existing blind equalizer convergence rate and residual inter-symbol interference using constellation reduced and cost function by separation the real part and an imaginary part, the dual structure CR-CMA(constellation Reduction CMA). The CMA methed compensates amplitude but does no compensate phase, On the other hand, The CMA method compensates both the amplitude and the phase but it has the convergence rate problem, and the MCMA method is a way to solve the phase problem of CMA method compensates both the amplitude and the phase after respectively calculating the real part and imaginary part components. Proposal a new method that the dual structure of CR-CMA, the cost function and error function and respectively calculating the real part and imaginary part components can advantages by improving the CMA and the MCMA algorithms so that the amplitude and phase retrieval and constellation reduce the residual ISI and faster convergence rate and performance is good SER (Symbol Error Ratio) was confirmed by computer simulations.

RCA 비용 함수를 개선한 Advanced CMA 등화기 알고리즘

In this paper, the concerned CMA (Constant Modulus Algorithm) adaptive equalizer convergence rate and residual inter-symbol interference using cost function in order to improved to the ACMA (Advanced CMA). The CMA method compensates amplitude but does not compensate phase. On the other hand, The RCA (Reduced Constellation Algorithm) method compensates both the amplitude and the phase but it has the convergence rate problem. MCMA method is a way to solve the phase problem of CMA method compensates both the amplitude and the phase after respectively calculating the real and imaginary components. But it is more than poor CMA method in the complexity of hardware and the compensation performance. The cost function can advantages by improving the CMA and a MCMA (Modified CMA) equalizer so that the amplitude and phase retrieval the equalization steady-state to reduce the error by using ISI and faster convergence rate and performance is good SER (Symbol Error Ratio) was confirmed by computer simulations.

Performance analysis of network coding for multicast relay system over Nakagami-m fading channels

The outage probability performance of network coding for multicast relay system is analyzed in Nakagami-m fading channels. Two transmission strategies, i.e., complex field network coding (CFNC) and amplify-and-forward network coding (AFNC), are applied in the system, and the approximate expressions of outage probability are derived at high SNR and the conclusion is reached that the system diversity gains of two transmission strategies are both 2m, as is verified by numerical simulations. Simulation results also show that CFNC can outperform both AFNC and direct transmission without relay in the performances of system outage probability, sum rate and symbol error ratio.

Theoretical analysis of ICI self-cancellation in OFDM systems over Rayleigh flat-fading channels

Orthogonal frequency division multiplexing (OFDM) has been widely used for its robustness against multipath fading and low-complexity implementation. However, OFDM system, especially with large number of subcarriers and high modulation order, is severely affected by the phase noise of oscillators and carrier frequency offset (CFO). On the other hand, self-cancellation schemes have received a lot of attention due to their simple implementation and high efficiency to suppress inter-carrier interference (ICI) in OFDM systems. Among those ICI self-cancellation methods, symmetric conjugate symbol repetition (SCSR) has been proven to have the best bit error ratio (BER) performance for phase noise suppression. In this paper, the performance of OFDM systems with SCSR ICI self-cancellation in the presence of both phase noise (PHN) and CFO are investigated, and analytical expressions are derived to calculate error probability evaluated by symbol error ratio (SER) over additive white Gaussian noise (AWGN) and Rayleigh flat fading channels. An approach of second order approximation of PHN/CFO has been performed to estimate the residual ICI, which could provide more accurate results. Simulation results show perfect agreement with those obtained by theoretical analysis, which could be used to estimate OFDM system error probability, facilitating the design of the overall system.

Unified Bit-Based Probabilistic Data Association Aided MIMO Detection for High-Order QAM Constellations

A unified bit-based probabilistic data association (B-PDA) detection approach is proposed for multiple-input-multiple-output (MIMO) systems employing high-order rectangular quadrature amplitude modulation (QAM). The new approach transforms the symbol detection process of QAM to a bit-based process by introducing a unified matrix representation (UMR) of QAM. Both linear natural and nonlinear binary reflected Gray bit-to-symbol mappings are considered. With the aid of simulation results, we demonstrate that the linear-natural-mapping-based B-PDA approach typically attained an improved detection performance [measured in terms of both bit error ratio (BER) and symbol error ratio (SER)] in comparison with the conventional symbol-based probabilistic data association (PDA)-aided MIMO detector, despite its dramatically reduced computational complexity. The only exception is that, at low SNRs, the linear-natural-mapping-based B-PDA is slightly inferior in terms of its BER to the conventional symbol-based PDA using binary reflected Gray mapping. Furthermore, the simulation results show that the linear-natural-mapping-based B-PDA MIMO detector may approach the best-case performance provided by the nonlinear binary reflected Gray-mapping-based B-PDA MIMO detector under ideal conditions. Additionally, the implementation of the B-PDA MIMO detector is shown to be much simpler in the case of the linear natural mapping. Based on these two points, we conclude that, in the context of the uncoded B-PDA MIMO detector, it is preferable to use the linear natural bit-to-symbol mapping, rather than the nonlinear Gray mapping.

Channel estimation technique in multi-antenna AF relay communication systems

The channel estimation technique is investigated in OFDM communication systems with multi-antenna Amplify-and-Forward (AF) relay. The Space-Time Block Code (STBC) is applied at the transmitter of the relay to obtain diversity gain. According to the transmission characteristics of OFDM symbols on multiple antennas, a pilot-aided Linear Minimum Mean-Square-Error (LMMSE) channel estimation algorithm with low complexity is designed. Simulation results show that, the proposed LMMSE estimator outperforms least-square estimator and approaches the optimal estimator without error in the performance of Symbol Error Ratio (SER) under several modulation modes, and has a good estimation effect in the realistic relay communication scenario.

Performance Analysis of OFDM-Based Decode-and-Forward Relay Network with Multiple Interferers over Rayleigh Fading Channels

We consider an OFDM-based decode-and-forward relay network with multiple uncorrelated equal power interferers over frequency-selective Rayleigh fading channels and derive a unified closed-form expression of average symbol-error ratio for M- ary phase-shift-keying (M-PSK) modulation. Simulations are carried out to validate our analyses.

PLL demodulation technique for M-ray Position Phase Shift Keying

The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying (MPPSK) to send data and Phase Locked Loop (PLL) based techniques for data retrieve. With a single PLL, MPPSK demodulation is achieved, as well as carrier recovery and symbol synchronization. Firstly, MPPSK modulation method is briefly introduced. 2PPSK’s PSD expression is given with its optimization result. Orthogonal Phase Detector (PD) and static threshold are used for the purpose of wider phase range and simplicity in demodulation. The data rate is alterable, which is 4.65 kbps for 2PPSK and 9.3 kbps for 4PPSK in the paper. Then some indicative comparisons in Signal to Noise Ratio Symbol Error Rate (SNR-SER) are made among 2PPSK, 3PPSK and 4PPSK, of which 4PPSK has proved to be optimal in ten slots each symbol conditions. And finally, it is demonstrated by system simulations that lower than 10−4 Symbol Error Rate (SER) performance can be obtained at 13 dB symbol SNR.

Iteratively Decoded Variable Length Space-Time Coded Modulation: Code Construction and Convergence Analysis

An iteratively decoded variable length space time coded modulation (VL-STCM-ID) scheme capable of simultaneously providing both coding and iteration gain as well as multiplexing and diversity gain is proposed. Non-binary unity-rate precoders are employed for assisting the iterative decoding of the VL-STCM-ID scheme. The discrete-valued source symbols are first encoded into variable-length codewords that are mapped to the spatial and temporal domains. Then the variable-length codewords are interleaved and fed to the precoder assisted modulator. More explicitly, the proposed VL-STCM-ID arrangement is a jointly designed iteratively decoded scheme combining source coding, channel coding, modulation as well as spatial diversity/multiplexing. As expected, the higher the source correlation, the higher the achievable performance gain of the scheme becomes. Furthermore, the performance of the VL-STCM-ID scheme is about 14.6 dB better than that of the fixed length STCM (FL-STCM) benchmarker at a source symbol error ratio of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup>

Channel Estimation and Interference Cancellation for MIMO-OFDM Systems

This paper proposes a new channel estimation method and a new interference cancellation scheme for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems in the presence of intersymbol interference (IS1). The proposed channel estimation method uses special training sequences (TSs) to have a desirable crest-factor of the transmitted training signal, and to prevent the influence of ISI on the channel estimation performance. By using the recommended training sequences, the ill-conditioned problem of the least square (LS) filter integrated in the proposed channel estimator can be avoided. The proposed interference cancellation scheme uses the estimated channel coefficients and the channel state information (CSI) to reproduce the interference components, which are then iteratively cancelled from the received signals. To reduced the error-floor of the demodulated symbols using for the calculations of the interference components, the so-called remodulation technique is also included in the proposed interference cancellation scheme. Simulation results show that the proposed channel estimation method outperforms conventional channel estimation methods, especially in the presence of ISI and if the signal-to-noise ratio (SNR) is larger than 15 dB. The combination of the proposed method with a space-time block code (STBC) to combat the interference influences results in an excellent system performance in terms of symbol error ratio (SER). In comparison with a STBC MIMO-OFDM system with sufficient guard interval (GI), this combination gains 1.52 dB of SNR at the same SER of 1.1 10 -6 even after performing only one iteration of interference cancellation.

Multichannel joint detection of multicarrier 16-qam ds/cdma system for high-speed data transmission

We propose a multichannel joint detector which eliminates other user, multipath, and intercarrier interference through a decorrelating process in a multicarrier 16-QAM direct-sequence code-division multiple-access system. The performance of the proposed detector under a frequency-selective fading channel is analytically derived and compared to that of a conventional single-user detector. The symbol error ratio curve of the proposed detector does not show the error floor that is seen in the conventional detector, and the resultant performance is close to that of a multicarrier 16-QAM system without any interference.