In previous literature on adaptive transmission in multiuser OFDMA systems, only uncoded case or capacity (coded with infinite length of codeword) has been considered. In this paper, an adaptive transmission algorithm for coded OFDMA systems with practical codeword lengths is investigated. Also, in order to keep the feedback overhead within a practical range, a two-step partial CQI scheme is ad...

Previous research efforts on OFDMA resource allocation have typically assumed the availability of perfect channel state information (CSI). Unfortunately, this is unrealistic, primarily due to channel estimation errors, and more importantly, channel feedback delay. In this paper, we develop optimal resource allocation algorithms for OFDMA systems assuming the availability of only partial (imperf...

In this paper, design and implementation of 4G SC-FDMA transceiver on FPGA is done and explained. Long Term Evolution (LTE) is next generation mobile communication standard from 3GPP, it is based on OFDMA) in Downlink Transmission and SC-FDMA in uplink Transmission. SC-FDMA is based on Frequency Division Multiple Access scheme. When compared with other multiple access scheme, it deals with the ...

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 OFDMA networks. The proposed method provides the ...

In recent, orthogonal frequency division multiple access (OFDMA) has been used for a multiuser wireless communication. In a wireless network, the transmitted signal of each user has independent channel fluctuation characteristic. By using this characteristic, OFDMA can achieve the multiuser diversity (MUDiv). Until this time, to achieve a low complexity and performance improvement, the adaptive...

The allocation of subcarriers and power to users is an important issue for exploiting the advantages of OFDMA systems. The main objective of the traditional OFDMA uplink resource allocation focuses on two aspects: one is to maximize the transmission rate of each user, the other is to minimize power. In this paper, we proposed the joint subcarrier and power allocation in the uplink of an OFDMA s...

In this work, we propose a Decision feedback equalizer (DFE) for Multiple Input Multiple Output (MIMO) DFT-spread OFDMA. This DFE can handle Multiple users, multiple antennas at the transmitter and receiver and the intersymbol interference in the received symbols of the DFT-spread OFDMA. The conventional method used in DFT-spread OFDMA is linear Frequency domain equalization (FDE). The DFE, wit...

OFDMA is the access scheme used in the third and fourth generation wireless cellular networks. Proper allocation of bandwidth and power is essential for ensuring the optimal performance and utilization of the resources in the OFDMA based cellular networks. The resource allocation in uplink direction and downlink directional will need different approaches. In uplink direction, different categori...

Orthogonal Frequency Division Multiple Access (OFDMA) is the promising technique for ever increasing demand of high data rate services. This paper proposes the Resource allocation issues for multiuser wireless transmissions, based on orthogonal frequency division multiple Access (OFDMA) and convex optimization techniques which are widely used in the design and analysis of variety of communicati...

Orthogonal frequency division multiple access (OFDMA) is a promising technique for high data rate communications in future cellular systems. Since frequency resources are universally reused in every cell in a system, a typical OFDMA system tries to maximize the spectral efficiency. Users located near the cell-edge tend to have the weakest signal strength. So they might experience severe inter-c...