Yong Huat Chew

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We model and study the amount of supported secondary system traffic for three opportunistic spectrum access schemes. We assume that the spectrum band is partitioned into C frequency bins, and whenever all are occupied, spectrum access by secondary radio (SR) will be blocked. On the other hand, an SR transmission is forced to terminate whenever a primary(More)
We address the adaptive allocation of subcarrier, bit and power in the downlink of multicell OFDMA systems which are operating at a frequency reuse factor of one. When a centralized scheduler is used, the presence of co-channel cell interference inter-relates the assignment of the subcarriers and powers in all the cells, making the optimal allocation of(More)
We use a Bayesian game-theoretic approach to model transmission control in energy-harvesting wireless sensor networks. In general, the energy state of an energy-harvesting sensor varies more dramatically with time as compared to traditional battery-powered sensors. Therefore, each energyharvesting sensor is aware of its instantaneous energy state, which is(More)
In this paper, we consider a scenario where distributed users in an OFDM-based system share the spectrum for transmission. Each network user (player) comprises a pair of transmit and receive nodes and will be allocated a given number of subcarriers. We propose a utility function that aims at efficiently allocating subcarriers to all players by minimizing(More)
In this letter, two direction-of-arrival (DOA) estimators are proposed: one is a new fourth-order cumulant-based technique, and the other is a joint second- and fourth-order cumulant technique. Using the full set of cumulants for DOA estimation is computationally expensive; conversely, using a downsized quadricovariance matrix leads to poor DOA estimates.(More)
Wireless orthogonal frequency-division multipleaccess (OFDMA) networks, where distributed users can access the spectrum dynamically, offer great flexibility and the potential for the efficient utilization of scarce spectrum resources. Despite that, managing such large-scale networks while maintaining fair and efficient spectrum usage poses a great(More)