Network coding has become a prominent approach to improve throughput of wireless networks. However, most of work in the literature concentrates mainly on 802.11-like random access networks. New technologies such as OFDMA (orthogonal frequency division multiple access), offer new opportunities for employing network coding. This paper considers how to apply the practical network coding scheme in ...

In previous studies on the capacity of orthogonal frequency division multiple access (OFDMA) systems, it is usually assumed that co-channel interference (CCI) from adjacent cells is a Gaussian-distributed random variable. However, very-little work shows that the Gaussian assumption does not hold true in OFDMA systems. In this paper, the statistical property of CCI in downlink OFDMA systems is s...

در این مقاله یک مدل ریاضی برای مسئله سیستم تولیدی همکارانه ساخت بر اساس سفارش با رعایت انصاف تخصیص بار‌های تولید طراحی شده است. اهداف اصلی مدل، کمینه‌سازی هزینه‌‌های کل و حداکثر استفاده از منابع به‌منظور عادلانه شرایط عدم­قطعیت کنترل پارامتر‌های غیرقطعی روش برنامه‌ریزی فازی ‌شده نتایج نشان می‌دهد افزایش نرخ عدم‌قطعیت، می­یابد. ازآنجاکه ظرفیت کارخانه‌ها ثابت است، مقدار تقاضا، هر کارخانه نیز می­ی...

In 4G technology especially LTE relaying and orthogonal frequency division multiple access (OFDMA) are widely accepted techniques in downlink. To obtain ubiquitous coverage with high data rate to user terminals even in difficult channel conditions (e.g. cell edge) a centralized RRM algorithm has been proposed for cellular fixed relay networks in downlink OFDMA. The

This paper proposes a general framework for the energy efficiency analysis of hybrid visible light communication (VLC) and Radio Frequency (RF) wireless system, in which both VLC RF subsystems utilize non-orthogonal multiple access (NOMA) technology. The proposed is based on realistic scenarios as it takes into account mobility users assumes imperfect channel-state information (CSI). In this co...

Radio link adaptation, multiple antenna techniques, relaying methods and dynamic radio resource assignment are among the key methods used to improve the performance of wireless communication networks. Opportunistic resource block (RB) allocation in downlink orthogonal frequency division multiple access (OFDMA) with limited feedback is considered. The spectral efficiency analysis of multiuser OF...

In this paper, we propose a new subcarrier allocation algorithm for a downlink OFDMA relay network with multicells. In the proposed algorithm, subcarriers are allocated to users and relays to maximize the overall sum of the achievable rate under fairness constraints. Simulation results show that the proposed algorithm achieves higher data rate than the static algorithm and reduces the outage pr...

a novel distributed frequency allocation scheme named as exponential distribution based frequency allocation (EDFA) is proposed in Fractional Frequency Reuse (FFR) aided OFDMA networks. EDFA has a flexible adjustment between fairness and throughput. Simulation results demonstrate that compared to the proportional fairness (PF) allocation and equal rate allocation (ERA) schemes, EDFA could achie...