Low complexity link level performance prediction for SIMO systems

Expressions are derived for the coverage probability and average rate of both multi-user multiple input multiple output (MU-MIMO) and single input multiple output (SIMO) systems in the context of a fractional frequency reuse (FFR) scheme. In particular, given a reuse region of $\frac{1}{3}$ (FR3) and a reuse region of 1 (FR1) as well as a signal-to-interference-plus-noise-ratio (SINR) threshold $S_{th}$ , which decides the user assignment to either the FR1 or FR3 regions, we theoretically show that: $1)$ the optimal choice of $S_{th}$ which maximizes the coverage probability is $S_{th} = T$ , where $T$ is the target SINR required for ensuring adequate coverage, and $2)$ the optimal choice of $S_{th}$ which maximizes the average rate is given by $S_{th}= T^{\prime}$ , where $T^{\prime}$ is a function of the path loss exponent, the number of antennas and of the fading parameters. The impact of frequency domain correlation amongst the OFDM sub-bands allocated to the FR1 and FR3 cell-regions is analysed and it is shown that the presence of correlation reduces both the coverage probability and the average throughput of the FFR network. Furthermore, the performance of our FFR-aided MU-MIMO and SIMO systems is compared. Our analysis shows that the (2 $\times$ 2) MU-MIMO system achieves 22.5% higher rate than the (1 $\times$ 3) SIMO system and for lower target SINRs, the coverage probability of a (2 $\times$ 2) MU-MIMO system is comparable to a (1 $\times$ 3) SIMO system. Hence the former one may be preferred over the latter. Our simulation results closely match the analytical results.

Massive multiple input multiple output (MIMO) is the key technology in the 5G communication network. Blind source separation (BSS) plays an important role in MIMO communication when information about the transmitted signals or channel is not available. Independent component analysis (ICA) is one of the well-known BSS technique applied in MIMO wireless communication. Existing BSS techniques like ICA assumes number of receiving antennas to be greater than or equal to the number of transmit antennas and hence cannot be applied to multiple input single output (MISO) communication scenario, that happens during downlink massive MIMO communication. In single channel blind source separation (SCBSS) the source signals are retrieved from a single observed mixture (single channel or single receiving antenna) of the source signals. In this paper, we investigate the application of SCBSS to MISO communication system. Using ensemble empirical mode decomposition (EEMD), the MISO communication system is converted to a pseudo MIMO system followed by the application of principal component analysis (PCA) and ICA algorithms to separate the transmitted signals. The algorithm is successfully applied to 2 X 1 MISO system and with a slight modification to n X 1 MISO system. Simulation results are provided to validate the performance of the algorithm.

The synthesis of mechanisms has an important effect in the product development. A mechanism has two basic kinds of functions, i.e. to transform motion and to transform force. However, current methods always focus on either motion synthesis or force synthesis. The paper proposed a dynamic programming-based synthesis of multi-input or multi-output mechanisms with the simultaneous consideration of motion and force transmission. A general function model is proposed with a result of function matrix of mechanisms. After the solving process of single input and single output (SISO) system using dynamic programming algorithm is proposed, the single input and multiple outputs (SIMO) system, and the multiple inputs and single output system (MISO) are also discussed in detail, together with design evaluation. The synthesis of mechanisms for jacking up system in offshore platform is taken as an example, which demonstrates that the methodology is helpful to produce valuable mechanisms.

In this paper, we consider Single Input Multiple Output (SIMO) systems with Maximum Ratio Combining(MRC) and Equal Gain Combining (EGC). We assume spatially independent and timely correlated Rayleigh flat fading channels, modeled by AR2 processes. We consider a frame of N+2 symbols, where Channel State Information at Receiver (CSIR) is available in the beginning for two consecutive symbols, also called as partial CSIR. Using this CSIR, we predict CSIR for the remaining N symbols and detect them. For this partially coherent systems, we have derived closed-form expressions of BER for BPSK constellation. We have also presented simulation results and verified our analytical expressions. We have shown the effects of frame size N, time varying condition of channel by doppler frequency ω <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</sub> on BER. We have compared performance of the SIMO systems with SISO system and shown significant improvement in BER over SISO systems.

In this paper, we have implemented high performance FPGA based pipelined tree architectures for a combined unsigned and two's complement comparator, and an equality comparator which checks whether the sum of two numbers is equal to a third number. The comparator architectures deviate from the combined Look-Up Table (LUT) and carry chain based implementation which is inferred by the Xilinx Synthesis Tool. The feasibility of this work comes from the increased device density offered by the 6 and 7 series FPGA architectures from Xilinx, where every dual output function derived from a single LUT can be registered using a flip-flop present within the same slice as that of the LUT. Pipelining a tree based architecture completely eliminates the requirement of any synchronization registers for balancing the arrival time of the inputs and outputs, and their associated placement and routing challenges. The architecture has been realized through primitive instantiation of the logic elements to ensure packing of the dual output functions into a single LUT wherever possible, and the placement of the LUTs on the FPGA fabric using appropriate placement constraints. Implementation results clearly reveal the superiority of our design paradigm over behavioral style of modeling, where our proposed architectures consume less area, and operates at a higher speed in comparison to an identical circuit realized using behavioral descriptions.

We evaluate the performance of single- and multi-antenna multi-carrier code division multiple access (MC-CDMA) downlink (base station to mobile terminal) systems in multi-cell environments. We first propose a minimum mean square error (MMSE) filter for a single input single output (SISO) MC-CDMA downlink system. Then, we apply it to a SIMO (single input multiple output) system with a conventional turbo coding. Furthermore, we compare the performance of SISO (1 /spl times/ 1) and SIMO (1 /spl times/ 2) MC-CDMA systems with that of a multiple input multiple output (MIMO) (2 /spl times/ 2) system employing space-time turbo coded modulation (STTuCM) in a multi-cell environment with 7 cells by computer simulation. Based on the computer simulation results, it is found that the considered MIMO system can achieve twofold capacity with the same transmission power in the multi-cell environment.

Modulation identification (MI) of an unknown communication signal plays a key role in various civilian and military applications, such as cognitive radio, spectrum surveillance, and electronic warfare systems. In this paper, a new MI algorithm for Ricean fading channel signals in wireless single input multiple output systems is proposed, which employs high-order moments as features for identification. The second-order moment and the fourth-order cross-moment matrix of the received signal envelope are used to estimate the moments of the transmitted data. The performance of the proposed algorithm is investigated through numerical simulations and compared with the MI algorithm in the literature.

In this paper, a single input multiple output system is considered with L receive antennas and the underlying channels are assumed to be time varying with temporal correlation coefficient a and spatially correlated with correlation coefficient $$\rho $$ . Further, the channel is assumed to be identically distributed using Rayleigh fading channels and characterized by first order autoregressive model. For the detection, we assume partial channel state information (CSI) available at the receiver. The partial CSI is in the form of a known preamble (one symbol) only before beginning of a frame of size N symbols. Further, the preamble is imperfectly known with a variance of error $$\sigma _e^2$$ . For the assumed system, closed form expressions of symbol error rate (SER) are derived for M-PSK and M-QAM constellations under the compound effect of spatially correlated channels, temporally correlated channels and partial CSI at the Receiver. The derived expressions are functions of average SNR per symbol, $$\rho $$ , a, $$\sigma _e^2$$ , N, L and modulation order M. Further, these expressions are reduced for some special cases and compared with prevailing results in literature. The analytical expressions are also validated by comparing them with the corresponding simulation results. The derived expressions are very useful to select N, L and M to overcome the deterioration in SER due to adverse effects of $$\rho $$ , a and $$\sigma _e^2$$ .

This study proposes a stripe artifact removal method based on robust principal component analysis (RPCA) for millimeter wave (MW) automotive radar images. With the development of MW radar detection technology, there is a demand for installing obstacle detectors on vehicular for safety. From this background, the authors developed squint-mode synthetic aperture radar (SAR) with MW (MW-SAR) as a high-resolution imaging technique. For synthesizing radar images, a back-projection algorithm (BPA) is adopted because of its real-time processing nature with high accuracy. However, SAR images obtained with Single Input and Single Output (SISO) systems are prone to be contaminated by a stripe-shaped artifact and can affect to the obstacle detection performance. Thus, to reduce the structured noise, this paper proposes successive RPCA on the assumption that the stripe artifacts and obstacle reflection are low-rank and sparse, respectively. As a solver, the alternating direction method of multipliers (ADMM) is adopted. The main contribution of this work is to initialize the ADMM state by taking account of the similarity of low-rank components between adjacent segments. Through simulations with experimental data, the significance of the proposed method is verified.

Interference caused by other users in a multi-user environment degrades the system performance significantly. Conventionally, user separation in a multi-user environment is achieved by signal separation in time, frequency or code. The use of multiple elements antenna (MEA) systems can apply separation of the users in space by targeting the transmitted power to the user of interest. Inevitably in that case, the separation is not ideal and there is interference on the other users in the systems. Moreover in a wideband transmission, frequency selective fading causing inter symbol interference (ISI) is a big challenge for point to point wireless communications. In this paper, we study the feasibility of applying the time reversal technique (TR) in multiple input single output (MISO) systems to alleviate the effect of ISI. The ability of TR to focus the signal on the receiver of interest in a multi-user environment is also considered. The studies are supported by measured complex channel impulse responses with 10 MHz bandwidth centered at 2.14 GHz. For an 8/spl times/1 MISO system, using TR the root mean square delay spread is reduced by a factor of 2. To evaluate the capability of the TR in reducing the ISI, simulation of the bit error rate (BER) was made. The irreducible BER of the TR-MISO system was shown to be lower than that of the SISO system by at least an order of magnitude. By using TR and assuming that two users are communicating simultaneously with the same BS the two signals have 17 dB of isolation.

Joint Beamforming and power allocation schemes are considered for cognitive radio (CR) multiple input single output (MISO) system in this paper. We considered the robust downlink beamforming and power allocation problem with per-antenna power constraints which is more realistic in practice, instead of sum-power constraint, under the imperfect channel state information (CSI). Since the given optimization problem is a non-convex problem which is difficult to handle, we transformed it into second order cone program (SOCP) problem, which can be solved efficiently. Simulation shows that the proposed scheme indeed has a better performance in CR system.

This letter presents a bit to symbol mapping scheme for spatial modulation multiple input single output systems. The proposed scheme relies on the transmitter knowledge of partial information about the channel’s magnitude and the phase for each transmit antenna. The aim of the proposed mapping is to minimize the hamming distance between adjacent symbols, which consequently, reduces the average bit error rate at the receiver. Monte Carlo simulation results corroborate the effectiveness of the proposed scheme as compared with the conventional and hybrid mapping schemes in the literature. As well, the proposed scheme is shown to be less complex as compared with the transmit antenna selection algorithms.

The interpolation functions of interval type-2 fuzzy systems and their universal approximation are investigated in this paper. Two types of fuzzification methods are designed to construct the antecedents and consequents of the type-2 inference rules. Then the properties of the fuzzy operator and the type-reduction algorithm are used to integrate all parts of the fuzzy system. Interpolation functions of interval type-2 fuzzy systems, which are proved to be universal approximators, are obtained based on three models, namely single input and single output, double inputs and single output, and multiple inputs and single output. The proposed approach is applied to approximate experiments of dynamic systems so as to evaluate the system performance. The system parameters are optimized by the QPSO algorithm. Experimental results for several data sets are given to show the approximation performances of the proposed interpolation functions are better than those of the interpolation function of the classical type-1 fuzzy system.

The objective of this research project is to develop an Active Noise Control (ANC) system based on the Filtered-X Least Mean Square algorithm. The ANC system developed here will be installed in a rocket engine testing facility of SpaceX Company near McGregor, Texas. As the SpaceX Company’s rocket engines have been increased in their powers, the engine noise from the testing facility is increasing rapidly. Although there is no noise complain currently from the nearby communities in McGregor, concerns are expected in the near future that the noise could possibly disturb people in McGregor. The ANC system can reduce the noise level using a few microphones and speakers connected to a DSP frontend, while a Passive Noise Control system would be much larger and require a higher cost to be implemented. This ANC system is currently implemented as a Single Input and Single Output system in a laboratory, effectively reducing the noise generated from a loudspeaker driven by the recorded rocket engine noise signal. Then, the system will be improved and operated as a Multiple Inputs and Multiple Outputs system to successfully adapt various wind, temperature, and humidity changes, leading to the maximum noise reduction toward McGregor.

Multiband simultaneous transmission (MST) system has been studied to enhance the spectral efficiency of wireless local area network (WLAN). In this system, information bits are divided into multiple bands and appropriately modulated taking account for the channel condition of each frequency band, and then a transmission frame consists of differently modulated symbols. To achieve higher spectrum efficiency, it is important to select an appropriate modulation and coding scheme satisfying an allowable frame error rate (FER). It means that FER prediction is a key technique to avoid low rate transmission and the frequent frame error. In this paper, we propose a FER prediction method for MST system. To predict the FER, we derive pairwise error probability (PEP) for this system. Moreover, we also consider the FER calculation based on the PEP for the WLAN system with a block interleaver. Furthermore, in order to improve prediction accuracy, we consider the impact of symbol error occurring beyond adjacent symbols on the PEP derivation. The simulation results show the accuracy of the proposed FER prediction method for both the additive white Gaussian noise channel and a multipath channel.