Scalable Architecture of MIMO Multi-carrier CDMA System on Programmable Logic

In this paper, a scalable architecture of the multicarrier CDMA system using Multiple-Input-Multiple-Output (MIMO) technology is designed in the programmable logic array. The system-level partitioning with different architecture design entries is described. The overall computing architecture for complex signal processing blocks, e.g., channel estimation, frequency domain equalization, demodulation etc is described. The MIMO architecture is easily extended from a SISO system with single antenna. This scalable architecture demonstrates resource utilization efficiency and easy extension to MIMO configurations

Probabilistically Bounded Soft Sphere Detection for MIMO-OFDM Receivers: Algorithm and System Architecture

Iterative soft detection and channel decoding for MIMO OFDM downlink receivers is studied in this work. Proposed inner soft sphere detection employs a variable upper bound for number of candidates per transmit antenna and utilizes the breath-first candidate-search algorithm. Upper bounds are based on probability distribution of the number of candidates found inside the spherical region formed around the received symbol-vector. Detection accuracy of unbounded breadth-first candidate search is preserved while significant reduction of the search latency and area cost is achieved. This probabilistically bounded candidate-search algorithm improves error-rate performance of non-probabilistically bounded soft sphere detection algorithms, while providing smaller detection latency with same hardware resources. Prototype architecture of soft sphere detector is synthesized on Xilinx FPGA and for an ASIC design. Using area-cost of a single soft sphere detector, a level of processing parallelism required to achieve targeted high data rates for future wireless systems (for example, 1 Gbps data rate) is determined.NokiaNational Science Foundatio

Reconfigurable Multi-Standard Uplink MIMO Receiver with Partial Interference Cancellation

As HSPA/HSPA+ and LTE/LTE-A evolve in parallel, the reconfigurability of a receiver to support multiple standards has become more and more important, especially for small cells. In this paper, we first suggest a reconfigurable multistandard uplink MIMO receiver based on a frequency domain equalizer. Then, to improve the performance, we propose two low-complexity partial iterative interference cancellation (IC) schemes to deal with the residual inter-chip and inter-antenna interference in HSPA/HSPA+ and the residual inter-symbol and inter-antenna interference in LTE/LTE-A. Compared with a receiver consisting of separate HSPA/HSPA+ and LTE/LTE-A uplink receivers, this reconfigurable receiver can save up to 66.9% complexity. Moreover, the two partial IC schemes have negligible performance loss compared with full IC scheme. They can achieve 2 dB gains in both standards with only 15.2% additional complexity to no IC scheme.Renesas MobileTexas InstrumentsXilinxSamsungHuaweiNational Science Foundatio

Structured Parallel Architecture for Displacement MIMO Kalman Equalizer in CDMA Systems

A reduced complexity MIMO Kalman equalizer architecture is proposed in this brief by jointly considering the displacement structure and the block-Toeplitz structure. Numerical matrix–matrix multiplications with O(F3) complexity are eliminated by simple data loading process, where is the spreading factor. Finally, an iterative Conjugate-Gradient based algorithm is proposed to avoid the inverse of the Hermitian symmetric innovation covariance matrix in Kalman gain processor. The proposed architecture not only reduces the numerical complexity from O(F2) to O(Flog2F) per chip, but also facilitates the parallel and pipelined VLSI implementation in real-time processing

High-Throughput Contention-Free Concurrent Interleaver Architecture for Multi-Standard Turbo Decoder

To meet the higher data rate requirement of emerging wireless communication technology, numerous parallel turbo decoder architectures have been developed. However, the interleaver has become a major bottleneck that limits the achievable throughput in the parallel decoders due to the massive memory conflicts. In this paper, we propose a flexible Double-Buffer based Contention-Free (DBCF) interleaver architecture that can efficiently solve the memory conflict problem for parallel turbo decoders with very high parallelism. The proposed DBCF architecture enables high throughput concurrent interleaving for multi-standard turbo decoders that support UMTS/HSPA+, LTE and WiMAX, with small datapath delays and low hardware cost. We implemented the DBCF interleaver with a 65nm CMOS technology. The implementation of this highly efficient DBCF interleaver architecture shows significant improvement in terms of the maximum throughput and occupied chip area compared to the previous work.HuaweiNational Science Foundatio

Rapid Industrial Prototyping and SoC Design of 3G/4G Wireless Systems Using an HLS Methodology

Many very-high-complexity signal processing algorithms are required in future wireless systems, giving tremendous challenges to real-time implementations. In this paper, we present our industrial rapid prototyping experiences on 3G/4G wireless systems using advanced signal processing algorithms in MIMO-CDMA and MIMO-OFDM systems. Core system design issues are studied and advanced receiver algorithms suitable for implementation are proposed for synchronization, MIMO equalization, and detection. We then present VLSI-oriented complexity reduction schemes and demonstrate how to interact these high-complexity algorithms with an HLS-based methodology for extensive design space exploration. This is achieved by abstracting the main effort from hardware iterations to the algorithmic C/C++ fixed-point design. We also analyze the advantages and limitations of the methodology. Our industrial design experience demonstrates that it is possible to enable an extensive architectural analysis in a short-time frame using HLS methodology, which significantly shortens the time to market for wireless systems.National Science Foundatio

Influence of soil qualities on intra- and interspecific competition dynamics of Larix kaempferi and L. olgensis

Forest management has potential to detrimentally impact long-term plantation productivity. Establishment of mixed plantations and fertilization are two important management approaches When trying to maintain soil qualities and productivity. In this study, two types of experiments were conducted to investigate the influence of soil qualities on intra- and interspecific competition dynamics in two larch species. Experiment 1: We transplanted two deciduous larch species, Larix kaempferi and L. olgensis, to study intra- and interspecific competition dynamics in two different types of soil: one from a c. twenty years old L kaempferi plantation (named larch soil) and another from a secondary natural forest (named mixed-forest soil). Experiment 2: Effects of N fertilization on the competition dynamics of the two larch species were tested in the larch soil. In the experiment 1, we hypothesized that the growth of L. kaempferi in the larch soil under no fertilization is inhibited when competing with L olgensis, and their competition relationships may be different in the mixed-forest soil. In both species, the starch and TNC (total nonstructural carbohydrate) concentrations of roots and shoots were significantly higher in the mixed-forest soil when compared to the concentrations in the larch soil without N fertilization (N). The relative competition intensity (RCI) was affected by the soil type. RCI of L. olgensis Was higher than that of L kaempferi in the larch soil N- condition, and RCI of L. kaempferi was higher than that of L. olgensis in the mixed-forest soil in 2015. However, the RCI values did not show significant differences in 2014. In the experiment 2, L. kaempferi showed superior competitiveness in the larch soil N+ condition, with the highest RCI value in 2014, but the RCI value of L kaempferi declined while the RCI value of L. olgensis increased from 2014 to 2015. Both experiments indicated that the benefiting species had higher element (C, N and P) and non-structural carbohydrate (starch and soluble sugar) content accumulation ratios from 2014 to 2015. We found that competition relationships changed between years and depending on conditions. We suggest that mixed plantations and N fertilization together could effectively promote the productivity of Larix. (C) 2016 Elsevier B.V. All rights reserved.Peer reviewe

Advanced MIMO-CDMA Receiver for Interference Suppression: Algorithms, System-on-Chip Architectures and Design Methodology

PhD ThesisMIMO (Multiple Input Multiple Output) technology is proposed in CDMA systems for much higher rate packet services. The receiver architecture is essential for the mobile devices to support high speed multimedia service. The design challenges come from both detection algorithms and hardware architectures. Much more complicated algorithms are required to suppress various interferences. However, the current hardware design archi-tecture and methodology is falling far behind the requirements of small size, low cost and power consumption. System-On-Chip (SoC) architectures are a major revolution taking place in the design of integrated circuits due to many advantages in the power consumption and compact size. The VLSI-oriented complexity reduction of the numerical algorithms plays an essential role to design efficient real-time architectures. Thus, the thesis contributes to three major as-pects: to propose high performance algorithms with realistic complexity in different chan-nel conditions; to propose real-time SoC architectures with area/speed/power efficiency; and to propose an efficient design methodology for modelling, partitioning/binding, verifi-cation and synthesis of the wireless systems. Specifically, to cut the design cycle and enable extensive architecture tradeoff study, an integrated wireless development methodology by High-Level-Synthesis for joint algorithm and architecture optimization is proposed. To address the performance/complexity tradeoff, we propose two LMMSE equalizer algorithms and SoC architectures for different channel conditions. Both an FFT circulant MIMO equalizer and a frequency domain iterative equalizer are proposed to avoid Direct-Matrix-Inverse for the well-conditioned channel as well as long channels working in bad conditions respectively. We then propose a displacement Kalman equalizer with VLSI-oriented architectural optimization for better performance in fast fading environments. For systems with the multi-usersâ signaling, we propose an adaptive Parallel-Residue-Compensation architecture with stage and user spe-cific weights by viewing the multiple transmitter antennas as virtual users to cancel the interferences explicitly. The increased accuracy in interference cancellation leads to signif-icant performance gain over both the complete and partial PIC. The complexity is reduced by using the commonality to avoid the direct interference cancellation. Finally, dynamic power management schemes are proposed to reduce the power consumption in the VLSI architectures using the inherent features of the interference suppression algorithms

Modeling of Welkin RF in a DSSS System

Elec 599 Project ReportIn this report, the author studied the methodology of distortion-true software modeling for RF (radio frequency) in a DSSS W-CDMA system. A complete end-to-end testbed based on the Welkin RF system is built by SystemView with specifications from real world RF components. This testbed includes digital baseband transmitter, RF transmitter, wireless channel, RF receiver, and baseband receiver for WLAN applications. Several implementation issues will be discussed. Various time/frequency domain analysis methods help to understand the non-linearity of real RF components in each stage and provide a reference to the hardware design. To support the capability of multi-domain simulation, Matlab custom tokens were integrated. The simulation results show the effects of noise figure introduced by RF on the receiver's sensitivity