A number of inter-cell interference coordination schemes have been proposed to mitigate the inter-cell interference problem for orthogonal frequency division multiple access (OFDMA) systems and among them, partial frequency reuse is considered one of the most promising approaches. In this paper, we propose an inter-cell interference mitigation scheme for an OFDMA downlink system, which makes us...

This paper investigates the adaptive subcarrier and bit allocation algorithm for OFDMA systems. To minimize overall transmitted power, we propose a novel adaptive subcarrier and bit allocation algorithm based on channel state information (CSI) and quality state information (QSI). A suboptimal approach that separately performs subcarrier allocation and bit loading is proposed. It is shown that a...

The 5th generation mobile communication system (5G) incorporates the latest technologies such as OFDMA, LDPC codes and millimeter wave in addition to MIMO. In order evaluate propagation characteristics of a complex system, it is very difficult at multiple frequencies. this paper, we propose method for estimating datarate wideband MIMO systems 5G using narrowband signals CW signals. an extension...

In recent years many papers have been published for energy-efficient resource allocation in a cellular OFDMA system. In this paper we carried out combined user scheduling and power optimization based on per subcarrier or per base station for each with maximum transmits power in coordinated BS. Here three definitions of the energy efficiency are considered for system design with channel rate and...

Relay assisted OFDMA networks are promising solutions for provision of high-data-rate services in wide coverage areas. However, the deployment of relays makes the resource allocation a more challenging and complex task. In this paper we study dynamic allocation of power and subchannels in an OFDMA downlink system with regenerative relays which have the capability of buffering the users’ data to...

Random medium access control (MAC) plays a critical role in OFDMA wireless networks to support services with bursty traffic. However, the existing OFDMA random access protocols suffer from low efficiency due to the constraints in half-duplex communications. In this paper, the capability of full-duplex communications is leveraged to propose novel mechanisms such as full duplex carrier sensing, c...

Deployment of relay nodes (RNs) in cellular orthogonal frequency division multiple access (OFDMA) systems provides an effective solution to increase high data rate coverage and improve cell throughput. However, a challenging issue is that additional interferences caused by RNs may substantially compromise the performance gain if no measure is taken. In this study, the authors address the proble...

This thesis deals with multiuser multicarrier communications over unknown time and frequency selective fading channels. Since there is a growing demand for capacity, especially in mobile communications, wireless multiuser communications experiences increasing interest in recent year. The wireless channel in general is a time and frequency selective fading channel. In that case, orthogonal frequ...

Introduction: Efficient packet based transmission with high data rate and high quality is considered as one of the requirements for future mobile communication systems [1]. In addition, a frequency reuse factor of one is preferred to make the cell planning and spectrum allocation easier. Frequency hopping orthogonal frequency division multiple access (FH-OFDMA) is among the multiple access cand...