• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.3
• /
• pp.1140-1155
• /
• 2021

Up to now, many state-of-arts have been proposed for two-way relaying system with linear modulations. The performances of antenna selection (AS) at both transmit and relay nodes need to be investigated in some two-way relaying multiple-input multiple-output (TWRM) systems. In this paper, the goal is focused on the study of nonlinear modulations, i.e., continuous phase modulation (CPM) in TWRM systems. Firstly, the joint phase trellis are simplified by reversed Rimoldi processing so as to reduce the systems' complexity. Then the performances of joint transmit and receive antenna selection (JTRAS) with CPM modulations in two-way relaying MIMO systems are analyzed. More exactly, the pair wise probability (PEP) is used to evaluate the error performance based on the CPM signal matrix, which is calculated in terms of Laurent expression. Since the channels subject to two terminal nodes share common antennas at relay node R in multiple-access scheme, we revise the JTRAS algorithm and compare it to existing algorithm via simulation. Finally, the error performances for various schemes of antenna selection are simulated and compared to the analysis in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.5
• /
• pp.504-511
• /
• 2016

In this paper, MIMO system based on turbo equalization techniques which LDPC codes were outer code and space time trellis codes (STTC) were employed as an inner code are studied. LDPC decoder and STTC decoder are connected through the interleaving and de-interleaving that updates each other's information repeatedly. In conventional turbo equalization of MIMO system, BCJR decoder which decodes STTC coded bits required two-bit wise decoding processing. Therefore duo-binary turbo codes are optimal for MIMO system combined with STTC codes. However a LDPC decoder requires bit unit processing, because LDPC codes can't be applied to these system. Therefore this paper proposed turbo equalization for MIMO system based on LDPC codes combined with STTC codes. By the simulation results, we confirmed performance of proposed turbo equalization model was improved about 0.6dB than that of conventional LDPC codes.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.3 s.333
• /
• pp.15-18
• /
• 2005

Multiple space-time codes (M-STTC) is composed of several space-time codes. That provides high transmission rate as well as diversity and coding gain without bandwidth expansion. In this paper, the layered receiver structures employing whitening process for M-STTC is proposed. The proposed receiver is composed of the decoding order decision block and the layered detection block. The whitening process in the latter is utilized to maximize the receive diversity gain in the layered detection. The layered receiver employing whitening process has more diversity gain and advantage of the required number of receive antenna over the layered detection with MMSE nulling. The proposed scheme achieves a 5dB gain compared to the coded layered space-time processing at the FER of $10^{-2}$.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.3A
• /
• pp.188-195
• /
• 2002

The M-algorithm for decoding convolutional codes can significantly reduce the complexity of the Viterbi algorithm by tracking a fixed number of survivor paths in each level of the decoding trellis. It is an easily-implementable algorithm suited for real-time processing of high-speed data. The algorithm, however, generates a sequence of catastrophic errors when the correct path is not included in the set of survivor paths. In this paper, the performance of the M-algorithm obtained from using various decoding complexity levels, frame lengths, and code constraint lengths is presented. The performance gain is quantified when the algorithm is used in conjunction with codes of increased constraint length. In particular, it is demonstrated the gain from the increased code free distance overcompensates the loss from the correct path being excluded from the survivors, when the frame length is short to moderate. Using 64 survivor paths, the signal-to-noise ratio gain obtained by increasing the constraint length from K=7 to K=9, 11, 15 is respectively 0.6, 0.75, and 08dB, when the frame of length L=100 has the frame error rate of 0.01%.

• The KIPS Transactions:PartC
• /
• v.11C no.1
• /
• pp.141-148
• /
• 2004

Recently, the demand of broadband communications such as high-speed internet, HDTV, 3D-HDTV and ATM backbone network has been increased drastically. For transmitting the broad-bandwidth data using wireless network, it is needed to use ka-band frequency. However, the use of this ka-band frequency is seriously affected to the received data performance by rain fading and atmospheric propagation loss at the Ka-band satellite communication link. So, we need adaptive MODEM to endure the degraded performance by channel environment. In this paper, we will present the structure and design of the 155Mbps adaptive Modem adaptively compensated against channel environment. In order to compensate the rain attenuation over the ka-band wireless channel link, the adaptive coding schemes with variable coding rates and the multiple modulation schemes such as trellis coded 8-PSK, QPSK, and BPSK are adopted. And the blind demodulation scheme is proposed to demodulate without Information of modulation mode at the multi-mode demodulator, and the fast phase ambiguity resolving scheme is proposed. The design and simulation results of adaptive Modem by SPW model are provided. This 155Mbps adaptive MODEM was designed and implemented by single ASIC chip with the $0.25\mu{m}$ CMOS standard cell technology and 950 thousand gates.

• Journal of Bio-Environment Control
• /
• v.18 no.4
• /
• pp.502-507
• /
• 2009

This study was conducted to establish the minimum harvesting time of 'Campbell Early' grape with girdling of 8 years old vines by the investigation of fruit quality. Girdling was performed as 5~7mm width at 1.0m height with a Y-trellis system on July 5th at Gimcheon, Gyeongbuk province. Skin color, soluble solids contents, sugar content, organic acid, and titratable acidity were analyzed every seven days period after the girdling. From 14 days after the girdling, pericarp color changed quickly as compared to the control, and also decreased b value and increased a value of Hunter L were observed. The content of organic acids decreased quickly as 0.85% as compared to the control's one, 1.10%. Sugar-acid ratio increased rapidly from the 21days as 15.1 against 10.8 of the control at harvesting time. After 14days, sugar content was abruptly increased such as fructose and glucose, that is 7days faster than the control. In harvesting time, their contents were high as $64.5mg{\cdot}g^{-1}FW$ and $61.0mg{\cdot}g^{-1}FW$ as compared to $56.1mg{\cdot}g^{-1}FW$ and $53.7mg{\cdot}g^{-1}FW$ of the control respectively. Among the content of organic acids, malic acid decreased quickly than the control's one in coloring time. The content of tartaric acid was obviously lower as $4.13mg{\cdot}g^{-1}FW$ than the control's one, $5.96mg{\cdot}g^{-1}FW$ in harvesting time. From these results, we assume that the harvesting of girdled 'Campbell Early' grape should be started in 42days after the girdling, when sugar-acid ratio is above 15.