Analog communication over selective fading channels Interim technical report

Demodulators for analog communication over slowly time varying, frequency selective fading channel

A Differential Feedback Scheme Exploiting the Temporal and Spectral Correlation

Channel state information (CSI) provided by limited feedback channel can be utilized to increase the system throughput. However, in multiple input multiple output (MIMO) systems, the signaling overhead realizing this CSI feedback can be quite large, while the capacity of the uplink feedback channel is typically limited. Hence, it is crucial to reduce the amount of feedback bits. Prior work on limited feedback compression commonly adopted the block fading channel model where only temporal or spectral correlation in wireless channel is considered. In this paper, we propose a differential feedback scheme with full use of the temporal and spectral correlations to reduce the feedback load. Then, the minimal differential feedback rate over MIMO doubly selective fading channel is investigated. Finally, the analysis is verified by simulations

Mobile Radio Channels Modeling in MATLAB

In this paper, a MATLAB based approach for mobile radio channels modeling is presented. Specifically, the paper introduces the basic concepts for modeling flat fading channels in MATLAB by means of user-defined m-files. Typical small-scale fading channel models are derived such as uncorrelated Rician fading channel and Rayleigh fading channel with Doppler shift. Further, simple and useful MATLAB constructions for approximation of cumulative distribution functions (CDFs) and probability density functions (PDFs) are also given. Finally, a MATLAB based Monte Carlo simulation example is presented, which comprises performance estimation of phase shift keying (PSK) signaling over a Rician fading channel

Energy Efficient Scheduling for Loss Tolerant IoT Applications with Uninformed Transmitter

In this work we investigate energy efficient packet scheduling problem for the loss tolerant applications. We consider slow fading channel for a point to point connection with no channel state information at the transmitter side (CSIT). In the absence of CSIT, the slow fading channel has an outage probability associated with every transmit power. As a function of data loss tolerance parameters and peak power constraints, we formulate an optimization problem to minimize the average transmit energy for the user equipment (UE). The optimization problem is not convex and we use stochastic optimization technique to solve the problem. The numerical results quantify the effect of different system parameters on average transmit power and show significant power savings for the loss tolerant applications.Comment: Published in ICC 201

Performance evaluation of 4-quadrature amplitude modulation over orthogonal frequency division multiplexing system in different fading channels scenarios

Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation (MCM) technique that divides the wide bandwidth into parallel narrow bands, each of which is modulated by orthogonal subcarriers. Currently, OFDM is a high-spectral efficiency modulation technique that is used in a variety of wired and wireless applications. The transmitted signal in a wireless communication channel spreads from transmitter to receiver through multiple reflective paths. This triggers multipath fading, which causes variations in the received signal's amplitude and phase. Slow/fast and frequency-selective/frequency-nonselective are the main types of multipath fading channels. Therefore, in this paper, we proposed new models for modeling multipath fading channels, such as the exponential fading channel and the Gamma fading channel. In addition, new bit-error-rate (BER) derivations have been derived. The performance of the OFDM system over proposed channel models has been evaluated using Monte-Carlo simulation and compared to the Rayleigh fading channel model. The obtained results via simulations show that the exponential fading channel at a rate parameter (λ=0.5) outperforms the Rayleigh fading channel by 6 dB for all values of Eb/No, while the Gamma fading channel at (α=2) outperforms the Rayleigh fading channel by 3 dB for all values of Eb/No

A novel scheme to aid coherent detection of GMSK signals in fast Rayleigh fading channels

A novel scheme to insert carrier pilot to Gaussian Minimum Shift Keying (GMSK) signal using Binary Block Code (BBC) and a highpass filter in baseband is proposed. This allows the signal to be coherently demodulated even in a fast Rayleigh fading environment. As an illustrative example, the scheme is applied to a 16 kb/s GMSK signal, and its performance over a fast Rayleigh fading channel is investigated using computer simulation. This modem's 'irreducible error rate' is found to be Pe = 5.5 x 10(exp -5) which is more than that of differential detection. The modem's performance in Rician fading channel is currently under investigation

Simulation of Doubly-Selective Compound K Fading Channels for Mobile-to-Mobile Communications

A computer simulation model is proposed for discrete-time doubly-selective compound-K fading channel. It first generates multiple independent mobile-to-mobile Rayleigh fading Channel Impulse Response (CIR) using the non-isotropic scattering model, then generates the cross- and auto-correlated gamma shadowing matrix using the combination of the memoryless nonlinear transformation (MNLT) method and the decomposition methods. It then combines the complex Rayleigh CIR with the gamma shadowing matrix to yield the doubly-selective fading channel CIR whose envelop follows the compound K distribution. Simulation examples demonstrate that the proposed method can effectively produce compound K fading channel responses with satisfactory statistical properties