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Wireless transceiver is a mandatory component of any kind of wireless sensors. Inside wireless transceiver, Viterbi decoder (VD) is needed to improve the decoding performance of the transceiver. In this paper, we propose a low complexity Viterbi decoder algorithm for wireless sensors that aim to support Internet of Thing (IoT) applications. Our algorithm is named as K-min Viterbi decoder because only...
To develop IoT sensor, research on low-cost and low-power wireless transceiver is necessary. Inside wireless transceiver, Viterbi decoder (VD) is one of the most complex but important block. VD is used in a receiver for decoding convolutional code from the transmitter and simultaneously correct bit errors. In addition, it is ceaselessly working circuit in a wireless transceiver, therefore it consumes...
Error-Control Coding (ECC) now plays an important role in wireless transceivers because it helps to increase link reliability and lower required transmit power. One popular problem of ECC implementation is the trade-off between high coding-gain and decoder's complexity. In this paper, we propose a serial concatenated ECC solution which is a combination of truncated-iteration layered-decoding LDPC...
In this paper, we propose a multiplier-reduction (MUL-RED) Radix-2 Pipeline FFT processor for 802.11ah IoT sensors. Utilizing the symmetry of Twiddle factors we show two ideas to reduce the hardware cost and power consumption. Firstly, the complex-multipliers in the last 4 layers are replaced by gain blocks. Secondly, in the remained layers we store only one fourth of the required Twiddle factors...
This research is our first step on the purpose of developing low-complex Viterbi decoder for IoT applications. We evaluate how the values of Viterbi decoder's parameters such as trace back length (L), input data bit-width (D), and LLR truncated value (E), affects to BER and PER of a communication system. The IEEE 802.11ah simulator is used with AWGN channel and BPSK modulation. Our simulation results...
In Multiple Input Multiple Output (MIMO) decoders, soft decision in the form of Log Likelihood Ratio (LLR) is often used to enhance the error correction probability of the Forward Error Correction (FEC). In order to compute the LLR, the zero's probability and the one's probability of an information bit must be known. In case of using the K-best maximum likelihood detection (MLD), only a subset of...
Although the K-best algorithm is well-known as an efficient suboptimal version of the maximum likelihood detection (MLD), its complexity is still significantly affected by the constellation size W. Especially, its sorting task is known as the major bottleneck. In this paper we propose a two dimensional (2D) sorter-based K-best algorithm, whose complexity is negligibly affected by W. Instead of considering...
In this paper, we propose a multi-mode low density parity check (LDPC) decoder architecture for high throughput wireless communication systems. Throughput of our decoder depends on code rate. The main blocks of our architecture are independent from value of the check matrix. Based on the proposed architecture, we design a twelve-mode Min-Sum LDPC decoder for IEEE 802.11ac system and synthesize it...
This paper proposes a hardware architecture of K-best-based 4 × 4 MIMO decoder that supports up to 256-QAM. The novelties such as Direct Expansion, and 2D Sorter play important roles on reducing the complexity of the decoder. In addition, the most complex operators such as divider and multiplier are eliminated in this design. As compared to the previous works, the proposed decoder achieves the highest...
In the field of multiple input multiple output (MIMO) decoder, K-best has been well investigated because it guarantees an SNR-independent fixed-throughput with a performance close to the optimal maximum likelihood detection (MLD). However, the complexity of its expansion and sorting tasks is significantly affected by the constellation size W. In this paper, we propose an algorithm and hardware design...
In this paper, we propose a low complexity algorithm for the maximum likelihood detection (MLD) of MIMO systems. Our algorithm separates the In-phase and Quadrature-phase components of a complex signal into two independent real numbers before calculating the Euclidean distance. Whereby, it is able to determine the closest constellation points directly without: 1) searching all of the candidates and...
Quantum surface effects (new emission bands, blueshifts, intensity enhancement) were observed in SPAN-80 activated ZnS nanocolloids and explained in terms of time-dependent density functional theory. The experimental evidences were demonstrated for both undoped and Cu, Mn-doped colloidal phases. The photoluminescence spectra of these materials showed a new green band at 520nm (ZnS:Cu) and a yellow-orange...
In this paper, we present an efficient and high throughput hardware implementation of the RC4 algorithm. The main idea of the proposed architecture is the utilization of a tri-port RAM to reduce the memory resource and to increase throughput. The proposed design requires two clock cycles for generating one byte of ciphering key and uses only a block of 256 bytes RAM. These result in 50% increment...
This paper shows the design and ASIC implementation of a 802.11n WLANs 4×4 MIMO OFDM PHY transceiver. The system supports the maximum data rate of 600Mbps. The MMSE-SQRD SIC MIMO decoder scheme, which has high BER performance and acceptable hardware cost, is implemented. To meet the required high throughput rate, parallel processing Scrambler/Descrambler, parallel processing BCC, and radix-4 soft-decision...
Changes in organic matter degradation and microbial communities during thermophilic composting were compared using two different types of anaerobic sludge, one from mesophilic methane fermentation, containing a high concentration of proteins (S-sludge), and the other from thermophilic methane fermentation, containing high concentrations of lipids and fibers (K-sludge). The difference in the organic...
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