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Multigroup ML Decodable Collocated and Distributed Space Time Block Codes
"... In this paper, collocated and distributed spacetime block codes (DSTBCs) which admit multigroup maximum likelihood (ML) decoding are studied. First the collocated case is considered and the problem of constructing spacetime block codes (STBCs) which optimally tradeoff rate and ML decoding complexi ..."
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Cited by 27 (19 self)
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In this paper, collocated and distributed spacetime block codes (DSTBCs) which admit multigroup maximum likelihood (ML) decoding are studied. First the collocated case is considered and the problem of constructing spacetime block codes (STBCs) which optimally tradeoff rate and ML decoding complexity is posed. Recently, sufficient conditions for multigroup ML decodability have been provided in the literature and codes meeting these sufficient conditions were called Clifford Unitary Weight (CUW) STBCs. An algebraic framework based on extended Clifford algebras is proposed to study CUW STBCs and using this framework, the optimal tradeoff between rate and ML decoding complexity of CUW STBCs is obtained for few specific cases. Code constructions meeting this tradeoff optimally are also provided. The paper then focuses on multigroup ML decodable DSTBCs for application in synchronous wireless relay networks and three constructions of fourgroup ML decodable DSTBCs are provided. Finally, the OFDM based Alamouti spacetime coded scheme proposed by LiXia for a 2 relay asynchronous relay network is extended to a more general transmission scheme that can achieve full asynchronous cooperative diversity for arbitrary number of relays. It is then shown how differential encoding at the source can be combined with the proposed transmission scheme to arrive at a new transmission scheme that can achieve full cooperative diversity in asynchronous wireless relay networks with no channel information and also no timing error knowledge at the destination node. Fourgroup decodable DSTBCs applicable in the proposed OFDM based transmission scheme are also given.
On Full Diversity SpaceTime Block Codes with Partial Interference Cancellation Group Decoding
"... In this paper, we propose a partial interference cancellation (PIC) group decoding strategy/scheme for linear dispersive spacetime block codes (STBC) and a design criterion for the codes to achieve full diversity when the PIC group decoding is used at the receiver. A PIC group decoding decodes the ..."
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Cited by 18 (6 self)
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In this paper, we propose a partial interference cancellation (PIC) group decoding strategy/scheme for linear dispersive spacetime block codes (STBC) and a design criterion for the codes to achieve full diversity when the PIC group decoding is used at the receiver. A PIC group decoding decodes the symbols embedded in an STBC by dividing them into several groups and decoding each group separately after a linear PIC operation is implemented. It can be viewed as an intermediate decoding between the maximum likelihood (ML) receiver that decodes all the embedded symbols together, i.e., all the embedded symbols are in a single group, and the zeroforcing (ZF) receiver that decodes all the embedded symbols separately and independently, i.e., each group has and only has one embedded symbol, after the ZF operation is implemented. The PIC group decoding provides a framework to adjust the complexityperformance tradeoff by choosing the sizes of the information symbol groups. Our proposed design criterion (group independence) for the PIC group decoding to achieve full diversity is an intermediate condition between the loosest ML full rank criterion of codewords and the strongest ZF linear independence condition of the column vectors in the equivalent channel matrix. We also propose asymptotic optimal (AO) group decoding algorithm which is an intermediate decoding between the MMSE decoding algorithm and the ML decoding algorithm. The design criterion for the PIC group decoding can be applied to the AO group decoding algorithm because of its asymptotic optimality. It is wellknown that the symbol rate for a full rank linear STBC can be full, i.e., nt, for nt transmit antennas. It has been recently shown that its rate is upper bounded by 1 if a code achieves full diversity with a linear receiver. The intermediate criterion proposed in this paper provides the possibility for codes of rates between nt and 1 that achieve full diversity with the PIC group decoding. This therefore provides a complexityperformancerate tradeoff. Some design examples are given.
FastGroupDecodable SpaceTime Block Code
"... Abstract—To make the implementation of highrate STBC realistic in practical systems, groupdecodable and fastdecodable code structures have been separately introduced into STBC to reduce the sphere decoding complexity. However, no STBC has both the two code structures until now. In this paper, hig ..."
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Cited by 17 (1 self)
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Abstract—To make the implementation of highrate STBC realistic in practical systems, groupdecodable and fastdecodable code structures have been separately introduced into STBC to reduce the sphere decoding complexity. However, no STBC has both the two code structures until now. In this paper, highrate fastgroupdecodable STBC (FGDSTBC, which has both fastdecodable and groupdecodable code structures) is proposed for the first time. We first derive the condition for fastdecodable code structure with the lowest sphere decoding complexity, then we prove that such fastdecodable code structure can be integrated with the groupdecodable STBC for FGDSTBC construction. Analysis and simulation show that the proposed FGDSTBC has much lower decoding complexity and comparable performance with the existing fastdecodable STBC (FDSTBC). I.
FastGroupDecodable STBCs via Codes over GF(4)
"... Abstract—In this paper we construct low ML decoding complexity STBCs by using the Pauli matrices as linear dispersion matrices. In this case the HurwitzRadon orthogonality condition is shown to be easily checked by transferring the problem to F4 domain. The problem of constructing low ML decoding c ..."
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Cited by 7 (2 self)
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Abstract—In this paper we construct low ML decoding complexity STBCs by using the Pauli matrices as linear dispersion matrices. In this case the HurwitzRadon orthogonality condition is shown to be easily checked by transferring the problem to F4 domain. The problem of constructing low ML decoding complexity STBCs is shown to be equivalent to finding certain codes over F4. It is shown that almost all known low ML decoding complexity STBCs can be obtained by this approach. New classes of codes are given that have the least known ML decoding complexity in some ranges of rate. I.
2Group MLDecodable STBCs for 2 m Transmit Antennas
 Proceedings of IEEE International Symposium on Information Theory, (ISIT 2009), Seoul, South Korea
"... is said to be gGroup MLDecodable (GMLD) if its Maximum Likelihood (ML) decoding metric can be written as a sum of 9 independent terms, with each term being a function of a subset of the K variables. In this paper, a construction method to obtain highrate, 2GMLD STBCs for 2 m transmit antennas, m ..."
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Cited by 4 (3 self)
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is said to be gGroup MLDecodable (GMLD) if its Maximum Likelihood (ML) decoding metric can be written as a sum of 9 independent terms, with each term being a function of a subset of the K variables. In this paper, a construction method to obtain highrate, 2GMLD STBCs for 2 m transmit antennas, m> 1, is presented. The rate of the STBC obtained for 2 m transmit antennas is 2 m 2 + 2 ~ complex symbols per channel use. The design method is illustrated for the case of 4 and 8 transmit antennas. The code obtained for 4 transmit antennas is equivalent to the rate5/4 QuasiOrthogonal design (QOD) proposed by Yuen, Guan and Tjung. I. INTRODUCTION AND BACKGROUND For STBCs in MIMO systems, rate, diversity and coding gain are three of the most important performance parameters.
BlockOrthogonal SpaceTime Code Structure and Its Impact on QRDM Decoding Complexity Reduction
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A class of fourgroup QuasiOrthogonal STBC achieving full rate and full diversity for any number of antennas
 PROCEEDINGS OF PIMRC 2005
, 2005
"... We propose and construct a new class of fullrate fulldiversity QuasiOrthogonal SpaceTime Block Code (QOSTBC), namely FourGroup QOSTBC (4GpQOSTBC), which can support any number of transmit antennas. 4GpQOSTBC can linearly separate the symbols into four independent groups, such that symbols wi ..."
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Cited by 1 (0 self)
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We propose and construct a new class of fullrate fulldiversity QuasiOrthogonal SpaceTime Block Code (QOSTBC), namely FourGroup QOSTBC (4GpQOSTBC), which can support any number of transmit antennas. 4GpQOSTBC can linearly separate the symbols into four independent groups, such that symbols within a group is orthogonal to all other symbols in another groups, and the maximumlikelihood (ML) decoder of the code only needs to jointly decode the symbols within the same group. The number of symbols required for joint detection of the newly proposed 4GpQOSTBC is half of that required by the existing QOSTBCs with the same code rate, and their fulldiversity decoding performances are comparable. We also extend the proposed code construction to obtain 6GpQOSTBC and 8GpQOSTBC, which have even lower decoding complexity, albeit at a slight loss in code rate.
FourGroup Decodable SpaceTime Block Codes
, 707
"... Abstract — Two new rateone fulldiversity spacetime block codes (STBC) are proposed. They are characterized by the lowest decoding complexity among the known rateone STBC, arising due to the complete separability of the transmitted symbols into four groups for maximum likelihood detection. The fi ..."
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Abstract — Two new rateone fulldiversity spacetime block codes (STBC) are proposed. They are characterized by the lowest decoding complexity among the known rateone STBC, arising due to the complete separability of the transmitted symbols into four groups for maximum likelihood detection. The first and the second codes are delayoptimal if the number of transmit antennas is a power of 2 and even, respectively. The exact pairwise error probability is derived to allow for the performance optimization of the two codes. Compared with existing lowdecoding complexity STBC, the two new codes offer several advantages such as higher code rate, lower encoding/decoding delay and complexity, lower peaktoaverage power ratio, and better performance. Index Terms — Orthogonal designs, performance analysis, quasiorthogonal spacetime block codes, spacetime block codes. I.
On Decoding and Performance Optimizing of FourGroup Decodable SpaceTime Block Codes
"... Abstract — A class of rateone spacetime block codes (STBC) allowing the decoding of transmitted symbols into four groups is recently proposed by Yuen, Guan and Tjhung. This code is called fourgroup decodable STBC (4GpSTBC). In this paper, the equivalent channel of 4GpSTBC is derived and a new m ..."
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Abstract — A class of rateone spacetime block codes (STBC) allowing the decoding of transmitted symbols into four groups is recently proposed by Yuen, Guan and Tjhung. This code is called fourgroup decodable STBC (4GpSTBC). In this paper, the equivalent channel of 4GpSTBC is derived and a new method to decode 4GpSTBC based on sphere decoders is proposed. Furthermore, the performance of 4GpSTBC is analyzed. A New signal rotation method is proposed, which performs better than the existing one. KeywordsSpacetime block codes, quasiorthogonal, performance analysis, low decoding complexity. I.