Allowable Outage Probability Research Articles

Secure-Reliable Transmission Designs for Full-Duplex Receiver With Finite-Alphabet Inputs

This paper studies a convincingly secure transmission framework under an allowable outage probability for practical finite-alphabet inputs, where a full-duplex receiver (Bob) is taken into account to emit the artificial noise for deteriorating the eavesdropper’s decoding performance. We develop a secure-reliable mechanism to take the place of prior secrecy rate (SR) maximization strategy, where a closed form expression is invoked for substituting the non-closed SR expression upon exploiting the multi-exponential decay fitting approach. Hence, the intractable expectation operation over a large number of noise samples is circumvented. Moreover, a pair of critical probabilities of the reliable transmission and secure outage are first analyzed, and then a low-complexity optimization scheme is formulated. Apart from designing the transmission scheme for classically secure networks consisting of a transmitter, Bob and an eavesdropper, we further carry out an investigation on conceiving a secure-reliable strategy against multiple Eves for improving the system’s extensibility. To this end, analytical expressions of both the reliability outage and secrecy outage probabilities for multiple-Eve scenarios are also derived. Furthermore, a pragmatic iterative solution is conceived for addressing the corresponding max-min optimization problem. Finally, the simulation results validate the significance of our considered secure-reliable transmission in terms of the average SR performance attained.

Optimal Energy Efficiency Based Power Adaptation for Downlink Multi-Cell Massive MIMO Systems

In this paper, the power transmission and energy efficiency (EE) in downlink multi-cell massive multiple-input-multiple-output (MIMO) systems are investigated and optimized. Most of the existing works do not take into account different user's quality of service (QoS) requirements. These models also depend on a fixed transmit power consumption, which cannot reflect the actual EE levels concerning QoS. Therefore, in this paper, a new base station (BS) transmit power adaptation is firstly introduced, termed the BSTPA method. The transmitted power is adapted to channel condition and user-level QoS including data rate requirement and maximum allowable outage probability to minimize the total BS radiated power. An analytical closed-form expression of the average BS transmit power adaptation is derived. Then, a corresponding iterative optimization algorithm is proposed to maximize the average EE per BS and obtain the optimal design parameters. The proposed optimization algorithm aims to globally achieve the optimal EE value with the optimal amount of data rate, the number of BS antennas, and users. Simulation results are demonstrated to verify our analytical findings. For a wide range of different design parameters, the results indicate that the proposed method obtains remarkably higher EE levels compared to the conventional scenario, particularly if per-antenna circuit power is very small. The optimization results show that the case with lower per-antenna circuit power can achieve about 4.5 times better EE gain than the case with higher per-antenna circuit power with 13.3% optimum data rate improvement.

Inverse Moment Matching Based Analysis of Cooperative HARQ-IR over Time-Correlated Nakagami Fading Channels

This paper analyzes the performance of cooperative hybrid automatic repeat request with incremental redundancy (HARQ-IR) and proposes a new approach of outage probability approximation for performance analysis. A general time-correlated Nakagami fading channel covering fast fading and Rayleigh fading as special cases is considered here. An efficient inverse moment matching method is proposed to approximate the outage probability in a closed form. The effect of approximation degree is theoretically analyzed to ease its selection. Moreover, diversity order of cooperative HARQ-IR is analyzed. It is proved that the diversity order is irrelevant to the time correlation coefficient $\rho$ , as long as $\rho , and full diversity from both spatial and time domains can be achieved by cooperative HARQ-IR under time-correlated fading channels. The accuracy of the analytical results is verified by computer simulations, and the results reveal that cooperative HARQ-IR scheme can benefit from high fading order and low channel time correlation. Optimal rate selection to maximize the long-term average throughput given a maximum allowable outage probability is finally discussed as one application of the analytical results.

Theoretical evaluation of spectral efficiency and outage probability of TDMA multihop cellular systems

AbstractFor TDMA cellular systems that introduced multihop transmission, the spectral efficiency and outage probability in a single‐cell environment are formulated and evaluated numerically. By using approximations, the numerical evaluation is also conducted in an interference‐limited multicell environment and compared to simulation results. In formulating these performances, the focus is on the common points of multihop transmission and symbol rate control, and a method similar to the performance evaluation method of rate‐adaptive TDMA cellular systems is applied. In particular, the opposite effects of multihop transmission on the spectral efficiency are explicitly considered. In a single cell environment, instead of lowering the spectral efficiency somewhat by the introduction of multihop transmission, the cell coverage satisfying the allowable outage probability could be clearly expanded. A multicell environment could be implemented with cell reuses with a smaller allowable outage probability resulting from the introduction of multihop transmission. Consequently, an improved spectral efficiency is expected. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(4): 1–10, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20366