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...

Cooperative communication has characteristics of offering spatial diversity by employing relays to improve communication efficiency significantly in wireless networks. One of the important design issues in cooperative communication is to optimize the power allocated to source and relay. The problem of allocating optimal power significantly affects the performance of the network as more power ra...

The rapidly growing demand for wireless communication makes efficient power allocation a critical factor in the network’s efficient operation. Power allocation in cellular networks with interference, where users are selfish, has been recently studied by pricing methods. However, pricing methods do not result in efficient/optimal power allocations for such systems for the following reason. Becau...

optimal allocation of water resources is an essential service in agriculture that must be considered by farmers. one of the most significant factors in optimal allocation of water resources in agriculture is to define optimal farm cropping pattern. in this study, in order to determine optimal cropping pattern and water resources allocation in central district of mashhad city (toos village), the...

In this paper, we study resource allocation problem in orthogonal frequency division multiple access multiple-input multiple-output (OFDMA-MIMO) relay systems and formulate the optimal instantaneous resource allocation problem including subcarrier assignment, relay selection and power allocation to maximize system capacity. Based on the assumption that the availability of perfect channel state ...

Restructuring of Electricity supply industry introduced many issues such as transmission pricing, transmission loss allocation and congestion management. Many methodologies and algorithms were proposed for addressing these issues. In this paper a power flow tracing based method is proposed which involves Matrices methodology for the transmission usage and loss allocation for generators and dema...

We propose a new scheme for multiple antenna transmission in the context of spread-spectrum signaling. The new scheme consists of using shifted Gold sequences to modulate independent information on the multiple antennas. We show that this strategy of using multiphase spreading (MPS) on different antennas greatly improves the throughput over currently known spread-spectrum multiple-antenna metho...

The paper examines multi-modulation schemes (MMSs) to increase the rate of our two new Complex Orthogonal Designs (CODs) proposed for eight transmit antennas, namely C1 and C2, corresponding to the Amicable Orthogonal Designs (AODs) (8;1,1,2,2;1,1,2,2) and (8;1,1,1,4;1,1,1,4), respectively. In addition, the optimal inter-symbol power allocation in the proposed codes in single modulation as well...

We formulate two versions of the power control problem for wireless networks with latency constraints arising from duty cycle allocations In the first version, strategic power optimization, wireless nodes are modeled as rational agents in a power game, who strategically adjust their powers to minimize their own energy. In the other version, joint power optimization, wireless nodes jointly minim...

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...