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This letter presents a novel detection strategy for Spatially-Multiplexed
Generalized Spatial Modulation systems. It is a multi-stage detection that
produces a list of candidates of the transmitted signal vector, sorted
according to the proximity of the data vector to one of the possible vector
subspaces. The quality metric and list-length metric s...
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Citations
... Optimal and suboptimal detection schemes have been proposed for the point-to-point SM/GSM MIMO context [2]- [5]. When the uplink communication of a multiuser system is considered, significant developments focus on single-activeantenna SM, such as [6], that presented the optimal detector in this scenario, and [7], that proposes a hybrid-processing-based approach for the SM uplink system in millimeter wave communication. ...
... This suboptimal detector, proposed in [5], performs separately the detection of the transmit antenna combination and the symbol vector, implementing a list-detection scheme that generates candidates to the GSM information vector of the nth user. In the first stage, the BS applies a filter bank on the received vector. ...
... Details about the operation of the dynamic control of the list size are found in [5]. The expressions for c oi , oi and λ are sequentially repeated until that the number of processed candidates is equal or higher than the list size. ...
Generalized spatial modulation is envisioned as a promising communication paradigm for the next communication systems, in which high data rates and reliability are important features, but also energy and infrastructure-saving solutions are sought. This work presents a variety of efficient suboptimal signal detection strategies for the uplink of multiuser GSM MIMO systems. They are comprised of user decoupling strategies followed by GSM signal detection schemes, and offer different balances of detection performance and computational complexity. Simulation results exhibit the performance of these strategies under different system scenarios and channel propagation effects.
... This detector, proposed in [6], [7], operates in two phases: 1-sorting of the transmit antenna combinations and 2-detection of transmitted symbols, being that the number of repetitions occurred in the Phase 2 is controlled by a variablesize list. Consider that the antenna combinations used by the users of the n-th class in one transmission can be represented for the D n -tuple q = (p 1 , p 2 , . . . ...
... In [6] is observed that the performance of the ML-W detector without the use of decoupling is superior in comparison to the performance ot the Projection-Based List detectors with and without lattice reduction. Meanwhile, in terms of computational complexity, is evidenced that the cost of the ML detector is much higher than the cost of other detectors. ...
This paper presents the results obtained from the conjunction of two techniques proposed for use in modern communication systems: Spatial Modulation (SM) and decoupled signal detection. Theoretical fundamentals of Spatial Modulation signal detection are covered, in addition to signal decoupling techniques that enable the separation at the base station of signals transmitted from different users, aiming at the simplification and utilization of detection procedures best suited to each user in the network. Performance analyses, in terms of bit error rate, and computational complexity, in terms of the average number of flops per detected symbol vector are carried out for the different associations of decoupling techniques and SM detectors.
... Further, a suboptimal nested maximum likelihood group detection algorithm, which greatly reduces the complexity of the optimal ML detector, was proposed for GSM scheme [10]. In [11], a projection-based list detector was proposed for GSM scheme, which was shown to significantly reduce the gap to the optimal ML detector with dramatically reduced computational complexity. Although these detectors have low complexity, a significant detection performance gap to the optimal detector still is observed. ...
Generalized spatial modulation (GSM) is a spectral and energy efficient multiple-input multiple-output (MIMO) transmission scheme. It will lead to imperfect detection performance with relatively high computational complexity by directly applying the original QR-decomposition with M algorithm (QRD-M) to the GSM scheme. In this paper an improved QRD-M algorithm is proposed for GSM signal detection, which achieves near-optimal performance but with relatively low complexity. Based on the QRD, the improved algorithm firstly transforms the maximum likelihood (ML) detection of the GSM signals into searching an inverted tree structure. Then, in the searching process of the M branches, the branches corresponding to the illegitimate transmit antenna combinations (TACs) and related to invalid number of active antennas are cut in order to improve the validity of the resultant branches at each level by taking advantage of characteristics of GSM signals. Simulation results show that the improved QRD-M detection algorithm provides similar performance to maximum likelihood (ML) with the reduced computational complexity compared to the original QRD-M algorithm, and the optimal value of parameter M of the improved QRD-M algorithm for detection of the GSM scheme is equal to modulation order plus one.
... After the pilots, the detected symbols in previous time instants are used. After the first iteration, the soft cancellation MMSE performs PIC by subtracting the soft replica of interference components from the received vector aš y = y − Hǔ, (33) whereǔ = [u 1 , u 2 , . . . , u k−1 , 0, u k+1 , . . . ...
In this paper, we propose a list detection scheme for the uplink scenario of multiuser MIMO (MU-MIMO) systems. The proposed technique employs a single lattice reduction (LR) transformation to modify the channel matrix between the users and the base station (BS), that produces a new nearly orthogonal channel matrix and allows a more efficient detection. After the LR transformation, a reliable candidate for the transmitted signal vector, provided by successive interference cancellation (SIC) detection with a cancellation ordering strategy based on the mean square error (MSE) in the LR domain, is obtained. An algorithm to decide if the current candidate has good quality or if it is necessary to further explore different orderings to improve the estimation quality is employed. The proposed algorithm sets a minimum number of candidates to be tested and employs a stopping criterion to keep the number of candidates from growing excessively. Simulation results indicate that the proposed variable list detection (VLD) scheme has a near-optimal performance while keeping its computational complexity well below that of the ML detector. An iterative detection and decoding (IDD) scheme based on the VLD algorithm is also developed, producing an excellent performance that approaches the single user (SU) scenario. Keywords—Multiuser multiple-input multiple-output (MU-MIMO), variable list detection (VLD), lattice reduction (LR), successive interference cancellation (SIC), iterative detection and decoding (IDD).
... It can be shown that if a system with equal-length orthogonal-columns channel matrix hypotheses is considered, the application of the normalized matched-filter, as given by (10) and (11), or of the projection matrix of the data vector y into the vector space spanned by H (i) , output vectors with equal Euclidean norm. This observation traces a link between the matchedfilter sorting presented here and the projection-matrix sorting employed in uncoded Generalized-SM systems [9]. ...
... The candidate quality is used to decide the amount of candidates that should be considered to perform a detection. This scheme has been applied in Spatial Modulation uncoded systems [9]. The length of the candidate list may be expressed in terms of a cost function that represents the closeness of the solution. ...
In this paper, we present a detection algorithm for single-carrier generalized spatial modulation in frequency-selective fading channels. We extend the ordered-block minimum mean square error (OB-MMSE) detector, originally conceived for flat fading channels, to frequency-selective fading channels by exploiting the format of unique word-based single-carrier block transmission and incorporating decision feedback. Moreover, a frequency-domain prefilter is used to ameliorate error propagation and simplify the operation of OB-MMSE detector. Simulation results show the efficacy of the proposed algorithm.
Generalized spatial modulation (GSM), a special case of index modulation (IM), is a promising transmission scheme for the next-generation multiple-input-multiple-output (MIMO) communication network. By an encoding part of the information on the subsets of activated antennas, the GSM-MIMO is capable of achieving high energy efficiency with only a small number of radio-frequency (RF) chains. A modified computational efficient concentrated maximum likelihood (CECML) algorithm is first proposed to enable an efficient index sharing mechanism, which reduces computational complexity and facilitates parallelism for high-throughput detection. In addition, a joint subset QR preprocessing and successive interference cancellation (SIC) detection algorithm is developed to avoid matrix inversion operations in the minimum mean square error (MMSE) equalization. The proposed detector with QR preprocessing is capable of achieving near-optimal error rate performance as demonstrated by the numerical simulations. This paper also designed the GSM-MIMO detector chip based on the CECML-QRSIC algorithm for 4 x 64 GSM-MIMO systems with two active antennas using TSMC 40-nm CMOS technology. The synthesis and post-layout simulation results show that the proposed GSM-MIMO detection chip achieves a better normalized throughput, hardware efficiency, and energy efficiency than a previous SM-MIMO detector chip.
Spatial-Multiplexing aided Spatial Modulation (SMx-SM) is proposed, which intrinsically amalgamates the concept of Vertical Bell Labs Space-Time (V-BLAST) and Spatial Modulation (SM) to attain a high transmission rate, despite its low number of Radio Frequency (RF) chains at the transmitter. Specifically, in the SMx-SM scheme, the Transmit Antennas (TAs) are partitioned into groups and the SM technique is applied individually to each group. Furthermore, low-complexity threshold-aided Compressive Sensing (CS) based and Message Passing (MP) based detectors are derived for our SMx-SM system. Our simulation results show that the proposed SMx-SM system exhibits a better performance despite its lower complexity than the Conventional Generalized Spatial Modulation (CGSM) system. More importantly, the proposed SMx- SM system is capable of providing considerable performance gains over the V-BLAST system at the same number of RF chains and throughput. Finally, an upper bound is derived for the Average Bit Error Probability (ABEP), which is confirmed by our simulation results.
The generalized spatial modulation (GSM) is a new transmission technique that can realize high-performance multiple-input multiple-output (MIMO) communication systems with a low RF complexity. This paper presents an efficient sphere decoding method used to perform the symbol detection for the generalized spatial modulation (GSM) multiple-input multiple-output (MIMO) systems. In the proposed method, the cost metric is modified so that it does not include the cancellation of the nonexistent interference. The modified cost metric can be computed by formulating a detection tree that has a regular structure representing the transmit antenna combinations as well as the symbol vectors, both of which are detected efficiently by finding the shortest path on the basis of an efficient tree search algorithm. As the tree search algorithm is performed for the regular detection tree to compute the modified but mathematically-equivalent cost metric, the efficiency of the sphere decoding is improved while the bit-error rate performance is not degraded. The simulation results show that the proposed method reduces the complexity significantly when compared with the previous method: for the 6 × 6 64QAM GSM-MIMO system with two active antennas, the average reduction rate of the complexity is as high as 45.8% in the count of the numerical operations.
Generalized spatial modulation (GSM) is a recently proposed appealing multi-input multi-output (MIMO) transmission technique, which is capable of striking a tradeoff between the achievable transmission rate and the cost of radio frequency (RF) chains. In this letter, a novel low-complexity near-optimal soft decision (SoD)-aided detector is proposed for GSM, which considerably reduces the search space by employing a block minimum mean-squared error (B-MMSE) algorithm. Our simulation results show that the proposed detector is capable of achieving a better tradeoff between bit-error-rate (BER) performance and computational complexity compared with the existing matched filter (MF)-based SoD algorithms.
