Walsh Codes

. The design is synthesized using Xilinx Virtex4 XC4VLX200 device. The functional behavior is verified using Modelsim XE III 6.2 C. The delay and throughput values are obtained for variable payload sizes. Throughput-Power and Delay-Power characteristics are also verified for NoC.

Complex Hadamard matrices, consisting of unimodular entries with arbitrary phases, play an important role in the theory of quantum information. We review basic properties of complex Hadamard matrices and present a catalogue of inequivalent cases known for dimension N = 2, . . . , 16. In particular, we explicitly write down some families of complex Hadamard matrices for N = 12, 14 and 16, which we could not find in the existing literature.

. The design is synthesized using Xilinx Virtex4 XC4VLX200 device. The functional behavior is verified using Modelsim XE III 6.2 C. The delay and throughput values are obtained for variable payload sizes. Throughput-Power and Delay-Power characteristics are also verified for NoC.

Constant modulus transforms like discrete Fourier transform (DFT), Walsh transform, and Gold codes have been successfully used over several decades in several engineering applications, including discrete multi-tone (DMT), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) communications systems. In this paper, we present a generalized framework for DFT called Generalized DFT (GDFT) with nonlinear phase by exploiting the phase space. We show that GDFT offers sizable correlation improvements over DFT, Walsh, Oppermann and Gold codes, leading to better performance in all multi-carrier communications scenarios investigated. We also highlight how known constant modulus orthogonal transforms are special solutions of the proposed GDFT framework. Moreover, we introduce practical design methods offering computationally efficient implementations of GDFT as enhancements to DFT. We conclude the paper with examples of communications applications where GDFT is shown to outperform DFT and other known constant modulus bases.

NoC(network On Chip) is an efficient approach to design the communication subsystem between IP Cores in SoC(System On Chip). In this paper a CDMA(code division multiple access)bus is proposed as a communication interconnect for different IP cores. CDMA has been proposed as an alternative way for interconnect of IP cores in a SoC design, or as a solution for interconnecting modules within a system realized in several PCBs. Compared to a conventional TDMA-based bus this paper present how a multiprocessor system can benefit from the use of concurrent data transfers. The simulation of the system using VHDL code is carried out. The performance of the system and is evaluated.

Generalized Discrete Fourier Transform (GDFT) with non-linear phase is a complex valued, constant modulus orthogonal function set. GDFT can be effectively used in several engineering applications, including discrete multi-tone (DMT), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) communication systems. The constant modulus transforms like discrete Fourier transform (DFT), Walsh transform, and Gold codes have been successfully used in above mentioned applications over several decades. However, these transforms are suffering from low crosscorrelation features. This problem can be addressed by using GDFT transform. This paper describes the optimization of Generalized Discrete Fourier Transform with Non-Linear Phase for code division multiple access (CDMA). We have also implemented Gold, Walsh and DFT codes. Their performance is analyzed and compared on the basis of various parameters such as Maximum Value of Out-of-Phase Auto-Correlation, Maximum Value of Out-of-Phase Cross-Correlation, Mean-Square Value of Auto-Correlation, Mean-Square Value of Cross-Correlation and merit factor. The result of simulation in the form o f co mparison of Bit-error-rate (BER) and Signal-to-noise (SNR) ratio for various spreading codes is presented.

On-chip interconnects are the performance 1 bottleneck in modern system-on-chips. Code-division multiple 2 access (CDMA) has been proposed to implement on-chip 3 crossbars due to its fixed latency, reduced arbitration overhead, 4 and higher bandwidth. In CDMA, medium sharing is enabled 5 in the code space by assigning a limited number of N-chip 6 length orthogonal spreading codes to the processing elements 7 sharing the interconnect. In this paper, we advance overloaded 8 CDMA interconnect (OCI) to enhance the capacity of CDMA 9 network-on-chip (NoC) crossbars by increasing the number of 10 usable spreading codes. Serial and parallel OCI architecture 11 variants are presented to adhere to different area, delay, and 12 power requirements. Compared with the conventional CDMA 13 crossbar, on a Xilinx Artix-7 AC701 FPGA kit, the serial 14 OCI crossbar achieves 100% higher bandwidth, 31% less 15 resource utilization, and 45% power saving, while the parallel 16 OCI crossbar achieves N times higher bandwidth compared 17 with the serial OCI crossbar at the expense of increased area 18 and power consumption. A 65-node OCI-based star NoC is 19 implemented, evaluated, and compared with an equivalent space 20 division multiple access based torus NoC for various synthetic 21 traffic patterns. The evaluation results in terms of the resource 22 utilization and throughput highlight the OCI as a promising 23 technology to implement the physical layer of NoC routers. 24 Index Terms-Code-division multiple access (CDMA) 25 interconnect, CDMA router, network-on-chip (NoC), NoC 26 physical layer, overloaded CDMA crossbar. 27 I. INTRODUCTION 28 O N-CHIP communications profoundly impact the overall 29 area, performance, and power consumption of modern 30 system-on-chips (SoCs). Increasing the communication over-31 head degrades the speedup achieved by parallel computing 32 according to Amdahl's law [1]. Therefore, developing effi-33 cient high-performance on-chip interconnects has been of 34 paramount importance for the parallel and high-performance 35 computing technologies. Networks-on-chips (NoCs) are the 36 most scalable interconnection paradigm that is capable of 37 addressing various application needs and meet different perfor-38 mance requirements of heavy workloads [2], including latency 39 via adaptive routing [3], throughput via improved path diver-40 sity [4], power dissipation by optimizing the NoC to targeted 41 workloads [5], and flexibility by run-time configuration [6]. 42 In NoCs, data are treated as packets, while on-chip process-43 ing elements (PEs) are considered as network nodes inter-44 connected via routers and switches. NoCs provide a scalable 45

In this work, chaotic sequences with good auto-correlation properties are presented. The studied sequences are synthesized by means of the logistic map function and, been chaotic but fully deterministic, become a good alternative for well-known sequences, for example the Zadoff-Chu sequences, especially for small size sequences commonly used for frame synchronization purposes in digital communications systems. A new auto-correlation goodness metric is proposed, and it is employed as objective function in order to maximize the correlation goodness for short synchronization sequences synthesized by means the logistic map function.

A method to generate a large number of M-ary Perfect Periodic Autocorrelation (PPAC) codes of length N, with good correlation properties, is presented. N+1 perfect sequences are obtained if an inverse discrete Fourier transform (IDFT) is applied to a specific subset of N+1 bipolar sequences derived from maximal-length sequences. This set of perfect sequences has a maximum absolute value of periodic cross-correlation equal to the square root of N+1. Moreover, this absolute value is equal to 1 when all perfect sequences are in-phase.

In this paper, we present our solution to the Traffic4cast2020 traffic prediction challenge. In this competition, participants are to predict future traffic parameters (speed and volume) in three different cities: Berlin, Istanbul and Moscow. The information provided includes nine channels where the first eight represent the speed and volume for four different direction of traffic (NE, NW, SE and SW), while the last channel is used to indicate presence of traffic incidents. The expected output should have the first 8 channels of the input at six future timing intervals (5, 10, 15, 30, 45, and 60min), while a one hour duration of past traffic data, in 5mins intervals, are provided as input. We solve the problem using a novel sedenion U-Net neural network. Sedenion networks provide the means for efficient encoding of correlated multimodal datasets. We use 12 of the 15 sedenion imaginary parts for the dynamic inputs and the real sedenion component is used for the static input. The sede...

Recently, a theoretical framework for Generalized DFT (GDFT) with nonlinear phase functions exploiting the phase space to design various constant modulus orthogonal transforms was introduced. This paper extends prior work to design longer bases widely used in real world communications systems. GDFT provides flexibilities in phase space yielding performance improvements over other code families including DFT in correlation metrics. GDFT phase functions are optimally designed in order to reduce inter carrier interference (ICI) and inter-symbol interference (ISI) that dictate the performance of a multiuser channel. It is presented in the paper that superior correlation of GDFT over DFT manifests itself in improved BER performance in direct sequence CDMA based multiuser communications systems.

Complex Hadamard matrices, consisting of unimodular entries with arbitrary phases, play an important role in the theory of quantum information. We review basic properties of complex Hadamard matrices and present a catalogue of inequivalent cases known for the dimensions N = 2,…,16. In particular, we explicitly write down some families of complex Hadamard matrices for N = 12, 14 and 16, which we could not find in the existing literature.

Salah satu kelebihan utama sistem komunikasi Spread Spectrum adalah kemampuannya mengirimkan data informasi disertai kode-kode unik sehingga hanya perangkat penerima tertentu saya yang mampu mendeteksinya. Sangat banyak metode pembangkitan kode unik pada spread spectrum ini, salah satunya adalah direct sequence. Penerapan metode ini banyak direalisasikan pada teknologi CDMA, dikarenakan kesederhanaan rancangan dan relatif mudah dalam menganalisis karakteristik kerja sistemnya, terutama bagian sebaran kode unik pada sebuah lebar pita transmisi radio. Sumber kode unik dalam penelitian ini berasal dari data acak yang dihasilkan oleh pembangkit derau semu atau pseudo noise generator melalui pengaturan panjang kodenya sebesar 16, dengan tingkat kestabilan frekuensi sistem pembangkit kode unik dan frekuensi pembawa masing-masing sebesar 15,020 kHz dan 499,9419 kHz. Kedua frekuensi ini masing-masing menghasilkan nilai persen kesalahannya sebesar 0,0412 % dan 0,000049 %, sehingga dampaknya masih cukup baik bagi metode ini, apabila diimplementasikan pada teknologi CDMA, khususnya diperuntukan untuk laju kecepatan data rendah.

In this work, we consider design questions for an active optical lattice filter, which is being manufactured at the University of Texas at Dallas, and which has proven to be useful in the signal processing task of RF channelization. The filter can be described by a linear, discrete time state space model. The controlling agents, the gains, are embedded in the matrices intervening in this state space model. Consequently, techniques from linear feedback control theory do not apply. We concentrate on the question of finding real valued gains so that the A matrix of the state space model has a prescribed characteristic polynomial. We find that three of the coefficients can be arbitrarily picked, but that the remaining are constrained by these and the other system parameters. Our techniques use methods from constructive algebraic geometry.

Constant modulus transforms like discrete Fourier transform (DFT), Walsh transform, and Gold codes have been successfully used over several decades in several engineering applications, including discrete multi-tone (DMT), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) communications systems. In this paper, we present a generalized framework for DFT called Generalized DFT (GDFT) with nonlinear phase by exploiting the phase space. We show that GDFT offers sizable correlation improvements over DFT, Walsh, Oppermann and Gold codes, leading to better performance in all multi-carrier communications scenarios investigated. We also highlight how known constant modulus orthogonal transforms are special solutions of the proposed GDFT framework. Moreover, we introduce practical design methods offering computationally efficient implementations of GDFT as enhancements to DFT. We conclude the paper with examples of communications applications where GDFT is shown to outperform DFT and other known constant modulus bases.