A low-complexity semi-blind joint channel estimation and data detection scheme is proposed for space-time shift keying (STSK) based multiple-input multiple-output systems. The minimum number of STSK training blocks, w...
详细信息
A low-complexity semi-blind joint channel estimation and data detection scheme is proposed for space-time shift keying (STSK) based multiple-input multiple-output systems. The minimum number of STSK training blocks, which is related to the number of transmitter antennas, is first utilized to provide a rough initial least square channel estimate (LSCE). Then low-complexity single-stream maximum likelihood (ML) data detection is carried out based on the initial LSCE and the detected data are employed to refine the decision-directed LSCE. It is demonstrated that a few iterations are sufficient to approach the optimal ML detection performance obtained with the perfect channel state information.
This paper considers the use of an antenna selection mechanism to reduce the cost of multiple analog transmit/receive chains in multiple-input multiple-output (MIMO) systems. With the optimal antenna selection scheme,...
详细信息
This paper considers the use of an antenna selection mechanism to reduce the cost of multiple analog transmit/receive chains in multiple-input multiple-output (MIMO) systems. With the optimal antenna selection scheme, radio-frequency chains can optimally connect with the best subset of transmitter and/or receiver antennas. However, the optimal antenna selection algorithm requires an exhaustive search of all possible combinations to find the optimum subset at the transmitter and/or receiver, thus resulting in high complexity. In order to reduce the computational load while still maximizing channel capacity, we introduce the simulated annealing (SA) method, an effective algorithm that solves various combinatorial optimization problems, to search the optimal subset. The simulation results show that the performance of the proposed SA method provides almost the same channel capacity as that of the optimal exhaustive search algorithm while maintaining low complexity.
Linear Dispersion Codes (LDCs) have recently attracted numerous research interests. Thanks to their efficient spreading of data across both the time and spatial domains, LDCs are capable of achieving a desired Diversi...
详细信息
Linear Dispersion Codes (LDCs) have recently attracted numerous research interests. Thanks to their efficient spreading of data across both the time and spatial domains, LDCs are capable of achieving a desired Diversity-multiplexing Trade-off (DMT) in multipleinputmultipleoutput (MIMO) broadband wireless access systems. This paper proposes a novel LDC design method, which relies on the unitary matrix theory combined with a Genetic Algorithm (GA) aided optimization procedure. The proposed design provides a flexible framework, where new LDCs attaining higher data rates and better error resilience than a number of classic MIMO schemes can be generated.
We derive the exact and asymptotic symbol error rate (SER) of multiple-input multiple-output (MIMO) relaying with a fixed gain amplify-and-forward (AaF) relay in Nakagami-m fading channels. We demonstrate that both fi...
详细信息
We derive the exact and asymptotic symbol error rate (SER) of multiple-input multiple-output (MIMO) relaying with a fixed gain amplify-and-forward (AaF) relay in Nakagami-m fading channels. We demonstrate that both fixed and variable gain relaying achieve the same diversity, which is jointly determined by the number of antennas and the per-hop fading parameters. We further quantify the performance gap between fixed and variable gain relaying in terms of their array gains. We prove that this gap diminishes as the first and the second hops exhibit highly asymmetric channel qualities.
In this paper two complexity efficient soft sphere-decoder modifications are proposed for computing the max-log LLR values in iterative MIMO systems, which avoid the costly, typically needed, full enumeration and sort...
详细信息
In this paper two complexity efficient soft sphere-decoder modifications are proposed for computing the max-log LLR values in iterative MIMO systems, which avoid the costly, typically needed, full enumeration and sorting (FES) procedure during the tree traversal without compromising the max-log performance. It is shown that despite the resulting increase in the number of expanded nodes, they can be more computationally efficient than the typical soft sphere decoders by avoiding the unnecessary complexity of FES.
In this correspondence, we consider the optimality of beamforming for achieving the ergodic capacity of multiple-input multiple-output (MIMO) multiple access channel (MAC) via virtual representation (VR) model. We ass...
详细信息
In this correspondence, we consider the optimality of beamforming for achieving the ergodic capacity of multiple-input multiple-output (MIMO) multiple access channel (MAC) via virtual representation (VR) model. We assume that the receiver knows the channel state information (CSI) perfectly but that the transmitter knows only partial CSI, i.e., the channel statistics. For the single-user case, we prove that the capacity-achieving beamforming angle (c.b.a.) is unique, and there exists a signal-to-noise ratio (SNR) threshold below which beamforming is optimal and above which beamforming is strictly suboptimal. For the multi-user case, we show that the c.b.a is not unique and we obtain explicit conditions that determine the beamforming angles for a special class of correlated MAC-VR models. Under mild conditions, we show that a large class of power allocation schemes can achieve the sum-capacity within a constant as the number of users in the system becomes large. The beamforming scheme, in particular, is shown to be asymptotically capacity-achieving only for certain MAC-VR models.
This paper considers an optimized limited feedback design for a multi-antenna system serving multiple users under different types of channels: Rayleigh distributed and line-of-sight distributed channels. Since the use...
详细信息
This paper considers an optimized limited feedback design for a multi-antenna system serving multiple users under different types of channels: Rayleigh distributed and line-of-sight distributed channels. Since the users are asymmetric, we propose an optimized feedback bandwidth allocation scheme for users under a total feedback rate constraint. The allocation scheme is designed according to the long-term channel type information of users, and thus it can be efficiently implemented. Numerical results verify the effectiveness of our proposed scheme.
Unitary space-time modulation(USTM) fits for rapid Rayleigh flat fading channels as it can realize wireless communication when neither the transmitter nor the receiver knows the channel state information(CSI).However,...
详细信息
Unitary space-time modulation(USTM) fits for rapid Rayleigh flat fading channels as it can realize wireless communication when neither the transmitter nor the receiver knows the channel state information(CSI).However,an intrinsic problem is that only when the signal-to-noise ratio(SNR) is high can it give an ideal bit error rate(BER) *** existing bit-wise processing scheme of the combination of turbo code and USTM improves the BER performance and results in an unacceptable calculation complexity,storage and time delay *** this paper,we propose a multiary processing scheme and its corresponding multiary MAP decoding *** results verify that our scheme can reduce the system complexity while keep a good BER ***,we present the first analysis of the reason for the BER performance deterioration of the combination scheme at low SNR with the help of the definition of USTM.
A novel approach to joint blind channel estimation and data recovery is presented for high date rate multiple-input multiple-output (MIMO) systems operating over flat Rayleigh channels. The technique is based on indep...
详细信息
ISBN:
(纸本)9781424463985
A novel approach to joint blind channel estimation and data recovery is presented for high date rate multiple-input multiple-output (MIMO) systems operating over flat Rayleigh channels. The technique is based on independent component analysis (ICA) with particle filtering to track the time-varying channel. Given one value from the channel matrix coefficients' second-order statistics, non-stationary independent component analysis with a generalized exponential density function is used to separate each source signal. The performance is evaluated by simulation and is compared with optimal coherent detection as benchmark. Improved performance is demonstrated over the "conventional" blind approach with Kalman-based estimation, and over two known pilot-aided systems. Finally, the effect of time-selectivity of the channel on error performance is also assessed by simulation.
multiple-input multiple-output (MIMO) and Multi-User MIMO (MU-MIMO) systems have been expected to improve the channel capacity over a limited bandwidth of existing networks [1], [2]. The effects on channel capacity of...
详细信息
ISBN:
(纸本)9781424449682
multiple-input multiple-output (MIMO) and Multi-User MIMO (MU-MIMO) systems have been expected to improve the channel capacity over a limited bandwidth of existing networks [1], [2]. The effects on channel capacity of Single-User MIMO (SU-MIMO) systems in urban scenarios have been previously studied [3]. It has been clarified that the larger number of antennas cannot contribute the improvement on the channel capacity in urban SU-MIMO scenarios due to very high spatial correlation. In this paper, we focus on the MU-MIMO transmission because it can discriminate multiple users by the difference of Angle of Arrival (AoA). We compare the Multi Access Channel (MAC) capacity in uplink with the channel capacity in SU-MIMO by setting the total numbers of transmitting and receiving antennas of SU-MIMO and MU-MIMO to be the same. When the same numbers of antenna elements are used, the better performance is obtained with MU-MIMO in urban scenarios, unlike identical independent distributed (i.i.d.) channels which are generally assumed in MIMO transmission. We also clarify an interesting relationship between the channel capacity improvement of MU-MIMO compared with SU-MIMO and a path visibility.
暂无评论