Wireless Communications and Networking, IEEE Conference, 2007
The rate-one semi-orthogonal algebraic space-time (SAST) codes is recently introduced. In this pa... more The rate-one semi-orthogonal algebraic space-time (SAST) codes is recently introduced. In this paper, the authors propose a new signal design method for SAST codes so that the transmitted symbols can be divided into four groups for maximum likelihood (ML) detection; the authors call this new design of SAST codes four-group decodable SAST (4Gp-SAST) codes. The decoding complexity of 4Gp-SAST codes is greatly reduced compared with that of the original SAST codes, where the ML decoding of the transmitted symbols is made into two groups. The exact pair-wise error probability of 4Gp-SAST codes is derived and it is used to optimize the signal designs. Simulation results show that 4Gp-SAST codes perform better than several low complexity space-time block codes such as orthogonal and quasi-orthogonal codes.
Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed rec... more Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed recently by Khan and Rajan allow single-complex symbol decoding while offering higher data rates than orthogonal STBC. In this paper, we present the equivalent channels of CIOD codes. A new maximum likelihood metric is also derived, which is simpler than the one shown by Khan and Rajan. The exact symbol pair-wise error probability and a tight union bound on symbol error rate are derived. The tight union bound can be used to analyze the performance of CIOD codes with arbitrary constellations. We provide new optimal rotation angles based on minimizing the union bound for various constellations. Furthermore, a new signal design combining signal rotation and power allocation is presented for rectangular quadrature amplitude modulation.
Global Telecommunications Conference, . GLOBECOM . IEEE, 2006
ABBA codes are an important class of quasi- orthogonal space-time block codes proposed by Tirkkon... more ABBA codes are an important class of quasi- orthogonal space-time block codes proposed by Tirkkonen et al.. Recently, they have become more attractive for practical applications because Yuen et al. have shown that ABBA codes allow pair-wise real-symbol decoding (or equivalently, single-complex symbol decoding) complexity; it is the minimum decoding complexity (MDC) achievable by any non-OSTBC. Additionally, MDC-ABBA codes can achieve full diversity while their code rate is higher than that of OSTBC. In this paper, we present a new, general, simple, and closed-form method to decode MDC-ABBA codes. We explicitly derive the equivalent channel of MDC-ABBA codes and the maximum mutual information of MDC-ABBA. Furthermore, we prove that MDC-ABBA codes can achieve full diversity with transmit and/or receive antenna selection and full or limited feedback.
Global Telecommunications Conference, . GLOBECOM . IEEE, 2005
Quasi-orthogonal space-time block codes (QSTBC) achieve full diversity by constellation rotations... more Quasi-orthogonal space-time block codes (QSTBC) achieve full diversity by constellation rotations. Several authors have introduced optimal rotation angles, found either by computer search or by analytical derivation. However, existing analytical methods do not seem general enough to analyze optimal rotations for arbitrary constellations, and some previous results seem to conflict. We present a novel method to exactly derive the coding gain of QSTBC as a function of the rotation angle and the minimum Euclidean distance of two-dimensional constellations such as the ones carved from lattices of squares and triangles, and phase-shift keying (PSK) constellations. The upper bound of coding gain for amplitude PSK (APSK) is also obtained. We find the whole range of optimal rotations for maximizing the coding gain of QSTBC. Simulation results confirm the theoretical analysis
Global Telecommunications Conference, . GLOBECOM . IEEE, 2005
A new class of full-diversity space-time block codes (STBC) called semi-orthogonal algebraic spac... more A new class of full-diversity space-time block codes (STBC) called semi-orthogonal algebraic space-time block codes (SAST codes) with rate one symbol per channel use is proposed. The SAST codeword matrix has a generalized Alamouti code structure where the transmitted symbols are replaced by circulant matrices. Properties of rate-one linear threaded algebraic space-time (LTAST) codes are exploited to construct SAST codes with maximal coding gain. SAST codes attain nearly 100% of the Shannon capacity of open-loop multiple-input single-output (MISO) channels. Our theoretical analysis and simulation results show that SAST codes gain several dB over LTAST codes and also outperform other STBC
Global Telecommunications Conference, . GLOBECOM . IEEE, 2006
ABBA codes, a class of quasi-orthogonal space-time block codes (STBC) proposed by Tirkkonen et al... more ABBA codes, a class of quasi-orthogonal space-time block codes (STBC) proposed by Tirkkonen et al., have been studied extensively for various applications. Yuen et al. have recently shown that a refined version of ABBA codes admit pair-wise real-symbol decoding, i.e. with minimum decoding complexity (MDC) achievable by non-orthogonal STBC. In this paper, we derive the exact symbol pair-wise error probability and the union bound on the symbol error rate (SER). The union bound is only 0.1 dB from the simulated SER at medium or high SNR < 10-2. Thus, by minimizing the SER union bound, we can find the optimal signal designs for any constellation with an arbitrary geometrical shape. Furthermore, we propose a new method combining signal rotation and power allocation for inphase-quadrature power-unbalanced constellations such as rectangular QAM. Our new optimal signal designs perform better than the existing ones and offer lower encoding/decoding complexities.
IEEE Transactions on Wireless Communications, 2008
This letter presents a new method to directly analyze and optimize symbol error rate (SER) perfor... more This letter presents a new method to directly analyze and optimize symbol error rate (SER) performance of minimum decoding complexity (MDC) ABBA space-time block codes based on a tight union bound on SER. Additionally, a new signal transformation for rectangular quadrature amplitude modulation is proposed to provide better performance than the existing ones with lower encoding/decoding complexities. It is also shown that MDC-ABBA codes achieve full-diversity with antenna selection and limited feedback.
IEEE Transactions on Wireless Communications, 2008
Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed rec... more Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed recently by Khan and Rajan allow single-complex symbol decoding and offer higher data rates than orthogonal STBC. In this paper, we present the channel decoupling property of CIOD codes. A new general maximum likelihood method is derived, enabling the calculation of the symbol pair-wise error probability and union bound (UB) on symbol error rate (SER). Extensive simulation results show that the UB is within 0.1 dB from the simulated SER when SER < 10 −2 . The UB thus can be used to accurately predict and optimize the performance of CIOD codes. Furthermore, a new signal design combining signal rotation and power allocation is presented for constellations with uneven powers of real and imaginary parts such as rectangular quadrature amplitude modulation.
Wireless Communications and Networking, IEEE Conference, 2007
The rate-one semi-orthogonal algebraic space-time (SAST) codes is recently introduced. In this pa... more The rate-one semi-orthogonal algebraic space-time (SAST) codes is recently introduced. In this paper, the authors propose a new signal design method for SAST codes so that the transmitted symbols can be divided into four groups for maximum likelihood (ML) detection; the authors call this new design of SAST codes four-group decodable SAST (4Gp-SAST) codes. The decoding complexity of 4Gp-SAST codes is greatly reduced compared with that of the original SAST codes, where the ML decoding of the transmitted symbols is made into two groups. The exact pair-wise error probability of 4Gp-SAST codes is derived and it is used to optimize the signal designs. Simulation results show that 4Gp-SAST codes perform better than several low complexity space-time block codes such as orthogonal and quasi-orthogonal codes.
Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed rec... more Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed recently by Khan and Rajan allow single-complex symbol decoding while offering higher data rates than orthogonal STBC. In this paper, we present the equivalent channels of CIOD codes. A new maximum likelihood metric is also derived, which is simpler than the one shown by Khan and Rajan. The exact symbol pair-wise error probability and a tight union bound on symbol error rate are derived. The tight union bound can be used to analyze the performance of CIOD codes with arbitrary constellations. We provide new optimal rotation angles based on minimizing the union bound for various constellations. Furthermore, a new signal design combining signal rotation and power allocation is presented for rectangular quadrature amplitude modulation.
Global Telecommunications Conference, . GLOBECOM . IEEE, 2006
ABBA codes are an important class of quasi- orthogonal space-time block codes proposed by Tirkkon... more ABBA codes are an important class of quasi- orthogonal space-time block codes proposed by Tirkkonen et al.. Recently, they have become more attractive for practical applications because Yuen et al. have shown that ABBA codes allow pair-wise real-symbol decoding (or equivalently, single-complex symbol decoding) complexity; it is the minimum decoding complexity (MDC) achievable by any non-OSTBC. Additionally, MDC-ABBA codes can achieve full diversity while their code rate is higher than that of OSTBC. In this paper, we present a new, general, simple, and closed-form method to decode MDC-ABBA codes. We explicitly derive the equivalent channel of MDC-ABBA codes and the maximum mutual information of MDC-ABBA. Furthermore, we prove that MDC-ABBA codes can achieve full diversity with transmit and/or receive antenna selection and full or limited feedback.
Global Telecommunications Conference, . GLOBECOM . IEEE, 2005
Quasi-orthogonal space-time block codes (QSTBC) achieve full diversity by constellation rotations... more Quasi-orthogonal space-time block codes (QSTBC) achieve full diversity by constellation rotations. Several authors have introduced optimal rotation angles, found either by computer search or by analytical derivation. However, existing analytical methods do not seem general enough to analyze optimal rotations for arbitrary constellations, and some previous results seem to conflict. We present a novel method to exactly derive the coding gain of QSTBC as a function of the rotation angle and the minimum Euclidean distance of two-dimensional constellations such as the ones carved from lattices of squares and triangles, and phase-shift keying (PSK) constellations. The upper bound of coding gain for amplitude PSK (APSK) is also obtained. We find the whole range of optimal rotations for maximizing the coding gain of QSTBC. Simulation results confirm the theoretical analysis
Global Telecommunications Conference, . GLOBECOM . IEEE, 2005
A new class of full-diversity space-time block codes (STBC) called semi-orthogonal algebraic spac... more A new class of full-diversity space-time block codes (STBC) called semi-orthogonal algebraic space-time block codes (SAST codes) with rate one symbol per channel use is proposed. The SAST codeword matrix has a generalized Alamouti code structure where the transmitted symbols are replaced by circulant matrices. Properties of rate-one linear threaded algebraic space-time (LTAST) codes are exploited to construct SAST codes with maximal coding gain. SAST codes attain nearly 100% of the Shannon capacity of open-loop multiple-input single-output (MISO) channels. Our theoretical analysis and simulation results show that SAST codes gain several dB over LTAST codes and also outperform other STBC
Global Telecommunications Conference, . GLOBECOM . IEEE, 2006
ABBA codes, a class of quasi-orthogonal space-time block codes (STBC) proposed by Tirkkonen et al... more ABBA codes, a class of quasi-orthogonal space-time block codes (STBC) proposed by Tirkkonen et al., have been studied extensively for various applications. Yuen et al. have recently shown that a refined version of ABBA codes admit pair-wise real-symbol decoding, i.e. with minimum decoding complexity (MDC) achievable by non-orthogonal STBC. In this paper, we derive the exact symbol pair-wise error probability and the union bound on the symbol error rate (SER). The union bound is only 0.1 dB from the simulated SER at medium or high SNR < 10-2. Thus, by minimizing the SER union bound, we can find the optimal signal designs for any constellation with an arbitrary geometrical shape. Furthermore, we propose a new method combining signal rotation and power allocation for inphase-quadrature power-unbalanced constellations such as rectangular QAM. Our new optimal signal designs perform better than the existing ones and offer lower encoding/decoding complexities.
IEEE Transactions on Wireless Communications, 2008
This letter presents a new method to directly analyze and optimize symbol error rate (SER) perfor... more This letter presents a new method to directly analyze and optimize symbol error rate (SER) performance of minimum decoding complexity (MDC) ABBA space-time block codes based on a tight union bound on SER. Additionally, a new signal transformation for rectangular quadrature amplitude modulation is proposed to provide better performance than the existing ones with lower encoding/decoding complexities. It is also shown that MDC-ABBA codes achieve full-diversity with antenna selection and limited feedback.
IEEE Transactions on Wireless Communications, 2008
Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed rec... more Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed recently by Khan and Rajan allow single-complex symbol decoding and offer higher data rates than orthogonal STBC. In this paper, we present the channel decoupling property of CIOD codes. A new general maximum likelihood method is derived, enabling the calculation of the symbol pair-wise error probability and union bound (UB) on symbol error rate (SER). Extensive simulation results show that the UB is within 0.1 dB from the simulated SER when SER < 10 −2 . The UB thus can be used to accurately predict and optimize the performance of CIOD codes. Furthermore, a new signal design combining signal rotation and power allocation is presented for constellations with uneven powers of real and imaginary parts such as rectangular quadrature amplitude modulation.
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