• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.295-297
• /
• 2007

We design a new rate-3/2 full-diversity orthogonal space-time block code (STBC) for QPSK and 2 transmit antennas (TX) and 4 transmit antennas (TX) by enlarging the signalling set from the set of quaternions used in the Alamouti[I] and extendedcode and using additional members of the set of orthogonal matrices or Quasi-orthogonal matrices and higher than rate-5/4. Selective power scaling of information symbols is used to guarantee full-diversity while maximizing the coding gain (CG) and minimizing the transmitted signal peak-to-minimum power ratio (PMPR). The optimum power scaling factor is derived analytically and shown to outpetform schemes based only on constellation rotation while still enjoying a low-complexity maximum likelihood (ML) decoding algorithm.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04a
• /
• pp.511-513
• /
• 2004

IMT-2000 시스템에서 직교 STBC (Space-Time Block Code)와 같은 송신 다이버시티(diversity) 기법은 순방향 링크용량을 향상시킬 수 있다. 그러나 완벽한 다이버시티 (full diversity) 이득과 코드율 1 (full code rate)을 갖는 직교 STBC는 송신안테나 개수가 2개일 경우만 존재한다. 이 논문에서는 4개의 송신안테나와 1개의 수신안테나를 갖는 시스템에서 코드율 1 을 갖는 준직교 STBC를 사용할 경우 안테나 선택적 feedback 정보를 이용하여 완벽한 다이버시티 이득을 얻는 동시에 feedback 정보량은 줄일 수 있음을 보여 준다.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.6
• /
• pp.43-49
• /
• 2014

In this paper, we consider the performance evaluation of space time block code (STBC)) with coordinate interleaved orthogonal design (CIOD) over time selective channel. In case of quasi static channel, STBC-CIOD satisfies full rate and full diversity (FRFD) property with the single symbol decoding. However in the time selective channel, the symbol interference degrades the system performance when we employ the single symbol decoding. We derive the union bound of the symbol error probability by evaluating the pairwise error probability in the first order Markov channel. We also present simulation results of STBC-CIOD with QPSK.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.12A
• /
• pp.933-940
• /
• 2009

This paper proposes a robust detection scheme for quasi-orthogonal space-time block code over time-selective fading channels. The proposed detector performs interference cancellation and decision feedback equalization to remove the inter-antenna interference and inter-symbol interference when the channel varies from symbol to symbol. Cholesky factorization is used on the channel Gram matrix after performing interference cancellation to obtain feed forward equalizer and feedback equalizer. It is shown by simulations that the proposed detection scheme outperforms the conventional detection schemes and the exiting detection schemes to time-selectivity.

• ETRI Journal
• /
• v.28 no.1
• /
• pp.87-90
• /
• 2006

In this letter, we propose a quasi-orthogonal space-time-frequency (QOSTF) block coded orthogonal frequency division multiplexing (OFDM) that can achieve full symbol rate with four transmit antennas. Since the proposed QOSTF-OFDM cannot achieve full diversity, we use a diversity advantage collection with zero forcing (DAC-ZF) decoder to compensate the diversity loss at the receiving side. Due to modulation advantage and collected diversity advantage, the proposed scheme exhibits a better bit-error rate performance than other orthogonal schemes.

• Journal of information and communication convergence engineering
• /
• v.20 no.1
• /
• pp.1-7
• /
• 2022

Herein, a new space-time block coding technique is proposed for a MIMO 2 × 2 multiple-input multiple output (MIMO) system to minimize the bit error rate (BER) in Rayleigh fading channels with reduced decoding complexity using ZF and MMSE linear detection techniques. The main objective is to improve the service quality of wireless communication systems and optimize the number of antennas used in base stations and terminals. The idea is to exploit the correlation product technique between both information symbols to transmit per space-time block code and their own orthogonal Walsh-Hadamard sequences to ensure orthogonality between both symbol vectors and create a full-rate orthogonal STBC code. Using 16 quadrature amplitude modulation and the quasi-static Rayleigh channel model in the MATLAB environment, the simulation results show that the proposed space-time block code performs better than the Alamouti code in terms of BER performance in the 2 × 2 MIMO system for both cases of linear decoding ZF and MMSE.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.5C
• /
• pp.415-422
• /
• 2010

In this paper, we derive exact closed-form formulas, in terms of Meijer's G-function, for the ergodic capacity of space-time block codes (STBCs) from generalized linear complex orthogonal designs (GLCODs) and generalized coordinate interleaved orthogonal designs (GCIODs) in quasi-static frequency-nonselective i.i.d. Nakagami-m fading channels. The derived analytical results show an excellent agreement with Monte-Carlo simulation results. Thus, a useful means for analyzing and predicting the ergodic capacity performance of STBCs from GLCODs or GCIODs can be provided in various antenna configurations and different channel conditions without extensive Monte-Carlo simulations. We present some numerical results to verify the accuracy of the derived formulas.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.1
• /
• pp.21-26
• /
• 2013

In this paper we propose a system where we divide the group with 2 symbols. The two added symbols are separated by multiplexing and later added using the DE-multiplexing technique. In our proposed system a simple Partial Interference Cancelation (PIC) group decoding scheme is used for Double-ABBA(D-ABBA) Quasi-Orthogonal Space Time Code, which reduces the decoding complexity for the higher order Multiple Input Multiple Output (MIMO) space time block coding. Finally we compare the proposed scheme performance using the different modulation schemes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.12C
• /
• pp.1062-1067
• /
• 2008

ABBA codes, a class of quasi-orthognal space-time block codes (QoSTBC) proposed by Tirkkonen and others, allow full rate and a fast maximum likelihood (ML) decoding, but do not have full diversity. In this paper, a linear complex precoder is proposed for ABBA codes to achieve full rate and full diversity. Moreover, the same diversity produce as that of orthogonal space-time block code with linear complex precoder (OSTBC-LCP) is achieved. Meanwhile, the size of the linear complex precoder can be reduced by half without affecting performance, which means the same complexity of decoding as that of the conventional ABBA code is guaranteed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.8
• /
• pp.1785-1796
• /
• 2015

In this paper, we investigate achieving the full diversity order and power gains in case of using OSTBCs and quasi-OSBCs in the x channel system with interference alignment with more than 2 antennas at each terminal. A slight degradation is remarked in the case of quasi-OSTBCs. In terms of receiver structure, we show that due to the favorable structure of the channel matrices, the simple zero-forcing receiver achieves the full diversity order, while the interference cancellation receiver leads to degradations in performance. As compared to the conventional scheme, simulation results demonstrate that our proposed schemes achieve 14dB and 16.5dB of gain at a target bit error rate (BER) of 10^-4 in the case of OSTBCs with 3 and 4 antennas at each terminal, respectively, while achieving the same spectral efficiency. Also, a gain of 10dB is achieved at the same target BER in the case of quasi-OSTBC with 4 antennas at each terminal.