This paper proposes a new multiple-input–multiple-output (MIMO) technique called quadrature spatial modulation (QSM). QSM enhances the overall throughput of conventional SM systems by using an extra modulation spatial dimension. The current SM technique uses only the real part of the SM constellation, and the proposed method in this paper extends this to in-phase and quadrature dimensions. It is shown that significant performance enhancements can be achieved at the expense of synchronizing the transmit antennas. Additionally, a closed-form expression for the pairwise error probability (PEP) of generic QSM system is derived and used to calculate a tight upper bound of the average bit error probability (ABEP) over Rayleigh fading channels. Moreover, a simple and general asymptotic expression is derived and analyzed. Obtained Monte Carlo simulation results corroborate the accuracy of the conducted analysis and show the significant enhancements of the proposed QSM scheme.

Quadrature Spatial Modulation

A novel multiple-input multiple-output (MIMO) transmission scheme, called space-time block coded spatial modulation (STBC-SM), is proposed. It combines spatial modulation (SM) and space-time block coding (STBC) to take advantage of the benefits of both while avoiding their drawbacks. In the STBCSM scheme, the transmitted information symbols are expanded not only to the space and time domains but also to the spatial (antenna) domain which corresponds to the on/off status of the transmit antennas available at the space domain, and therefore both core STBC and antenna indices carry information. A general technique is presented for the design of the STBC-SM scheme for any number of transmits antennas. Besides the high spectral efficiency advantage provided by the antenna domain, the proposed scheme is also optimized by deriving its diversity and coding gains to exploit the diversity advantage of STBC. A low-complexity maximum likelihood (ML) decoder is given for the new scheme which profits from the orthogonality of the core STBC. The performance advantages of the STBC-SM over simple SM and over V-BLAST are shown by simulation results for various spectral efficiencies and are supported by the derivation of a closed form expression for the union bound on the bit error probability.

Space-Time Block Coded Spatial Modulation

The ITU-T draft H.264 video coding standard has been designed enabling a new generation of digital video applications.While the basic coding framework of the standard is similar to that of currently popular video standard, H.264 includes many coding features not present in earlier standard. We firstly introduces the important features and key techniques in H.264. Then, we presents the performance of it. Study on the new generation ITU-T draft H.264 is of great importance in application field.

Overview of the H.264 / AVC Video Coding Standard

http://ieeexplore.ieee.org/iel5/5/31328/01456984.pdf

Analog filter design

Generalized spatial modulation (GSM) uses N antenna elements but fewer radio frequency (RF) chains (R) at the transmitter. In GSM, apart from conveying information bits through R modulation symbols, information bits are also conveyed through the indices of the R active transmit antennas. In this letter, we derive lower and upper bounds on the the capacity of a (N, M, R)-GSM MIMO system, where M is the number of receive antennas. Further, we propose a computationally efficient GSM encoding method and a message passing-based low-complexity detection algorithm suited for large-scale GSM-MIMO systems.

On the Capacity and Performance of Generalized Spatial Modulation

Spatial Modulation (SM) is a newly introduced wireless transmission scheme, and Space Shift Keying (SSK) is its simplified version. Their capacity performance has not been well examined to date. Starting from basic definitions of information theory, through theoretical analyses and numerical calculations, this paper evaluates the capacity of SM systems in various channels. Our conclusion is that under Rayleigh fading channels, the capacity of the SSK system is limited by the Signal-to-Noise Ratio (SNR) or the number of transmit antennas, whichever one is smaller. From the capacity point of view, the SM system is better than the Single-Input and Single-Output (SISO) system, but worse than the Multiple-Input and Single-Output (MISO) system. The correlation between transmit antennas will degrade the performance of the SSK system. Line-of-Sight (LOS) may cause performance degradation for SSK, but capacity increases for SM.

Ergodic capacity analysis of spatially modulated systems

Orthogonal frequency division multiplexing (OFDM) systems based on discrete cosine transform (DCT) is proposed for the first time in this paper in order to solve the distortion due to great Peak-to-Average Power Ratio (PAPR) of OFDM systems signals. The character of the DCT energy focused is made use of in the frequency domain, and it helps to reduce the PAPR engendered by IFFT at the transmitter statistically, avoiding the nonlinear distortion in OFDM systems due to great change of PAPR. In this paper, the characters of DCT algorithm are analyzed first, and then the algorithm is applied to signal processing in OFDM systems. It is mathematically verified that this method is potent to reduce the PAPR. Lastly, the simulation results show that the proposed scheme in reducing the threshold of PAPR statistically is feasible.

A Novel Method Based DCT to Reduce PAPR of OFDM Systems

In this paper, two pilot-aided channel estimation methods are proposed, which use time frequency and frequency-transform domain methods. Their performance was contrasted by using them in the same channel conditions, their favorite application environments were analyzed and the effect of estimation error on system performance was studied. Theoretical analyses and mathematical simulation show that the time frequency domain method has wider application environment and its performance in channel estimation is better as well. Having applied this method to an adaptive OFDM system it is found that although the estimation error would reduce the system performance in some degree, the reduction is tolerable and with the increase of system SNR, the error would decrease simultaneously.

Two novel transform domain estimation methods for OFDM system and their application environment

Phase noise of transceiver local oscillator disturbs the orthogonality among subcarriers and causes inter-subcarrier-interference (ICI), which results in the significant degradation in the performance of wireless communication systems based on orthogonal frequency division multiplexing (OFDM). We observe that the inverse Fourier transform coefficient of the discrete phase noise varies gradually from a subcarrier to the next one in the middle subcarriers and is to be symmetric conjugate for the two end subcarriers. Based on this property, a novel ICI self-cancellation method is proposed in this paper to reduce the phase noise. Every data symbol is mapped onto a pair of adjacent subcarriers for the middle subcarriers and is mapped onto a pair of symmetric subcarriers for the two end subcarriers. As a result, it can be shown that common phase noise (CPE) becomes zero in the OFDM with the proposed method. Compared with other ICI self-cancellation method under the Spatial Channel Model (SCM) proposed by the Third Generation Partnership Project (3GPP), the bit error rate (BER) performance of the proposed method is much better. The simulations results show that it needs less signal-to-noise ratio to achieve the same BER performance in three environments of SCM: urban microcell, urban macrocell and suburban macrocell.

An improved OFDM phase noise cancellation method

To achieve an optimal trade-off between video quality and energy efficiency in the uplink streaming of multi-user Scalable Video Coding (SVC) videos in relay-based Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks, a cross-layer design framework that jointly selects the Transmission Policy (TP) for SVC video frames, assigns OFDMA subcarriers, and allocates power for each subcarrier is proposed. We apply the dual decomposition method to the problem, and obtain a TP selection subproblem for each SVC video adaptation and a resource allocation subproblem of Joint Subcarrier, Relay and Power Allocation (JSRPA). A second level of dual decomposition is used to divide the JSRPA problem into independent subcarrier subproblems. The proposed Cross-layer Trade-off Optimization (CTO) algorithm is sub-distributed with significantly low complexity. A performance evaluation with typical SVC video traces demonstrates that the proposed algorithm is able to converge and efficiently achieve the optimal trade-off between the video quality and energy consumption at the MSs for uplink SVC streaming.

Hou Chun-ping

Papers

Ergodic capacity analysis of spatially modulated systems

A Novel Method Based DCT to Reduce PAPR of OFDM Systems

Two novel transform domain estimation methods for OFDM system and their application environment

An improved OFDM phase noise cancellation method

Trade-off optimization for scalable video coding streaming in relay-based OFDMA networks