Learn More
— In a frequency reusing wireless local area network (WLAN), the co-channel interference (CCI) environment will change when new access points (APs) join the network. Therefore, the user throughput reduces if the available channels are not properly re-allocated. A newly joined AP is designed to measure the CCI levels on the available channels to select the(More)
For the realization of future wireless networks, gigabit wireless technology, which can achieve higher-than-1 Gbps data transmission with extremely low transmit power, is indispensable. We have been studying the distributed antenna network (DAN) and the frequency domain wireless signal processing. In DAN, many antennas or clusters of antennas are spatially(More)
The frequency-domain received single-carrier (SC) signal can be expressed using the matrix representation similar to the multiple-input multiple-output (MIMO) multiplexing. The signal detection schemes developed for MIMO multiplexing can be applied to the SC transmissions. In this paper, we apply maximum likelihood detection employing QR decomposition and(More)
Depth analysis of the optic nerve head (ONH) in the retinal fundus is important for the early detection of glaucoma. In this study, we investigate an automatic reconstruction method for the quantitative depth measurement of the ONH from a stereo retinal fundus image pair. We propose a technique to obtain the depth value from the stereo retinal fundus image(More)
Retinal image examination is useful for early detection of glaucoma, which is a leading cause of permanent blindness. In order to evaluate the presence of glaucoma, ophthalmologists may determine the cup and disc areas and diagnose glaucoma using a vertical cup-to-disc ratio. However, determination of the cup area based on computation algorithm is very(More)
— In this paper, we propose a direct/cooperative amplify-and-forward relay (D/AR) switching using a spectrum division/adaptive subcarrier allocation (SDASA) for increasing the uplink capacity of single carrier-frequency division multiple access (SC-FDMA). In the D/AR switching, switching between direct communication and cooperative AF relay is done so that(More)
—Multiple-input multiple-output (MIMO) spatial multiplexing is known to increase the transmission rate without bandwidth expansion. However, in cellular networks (CNs), the transmission rate of a user close to the cell edge significantly degrades because the received signal-to-interference plus noise power ratio (SINR) degrades due to the presence of strong(More)
—One-tap frequency-domain equalization (FDE) can significantly improve the bit error rate (BER) performance of single-carrier (SC) transmission in a frequency-selective fading channel. However, a big performance gap from the theoretical lower bound still exists due to the presence of residual inter-symbol interference (ISI) after FDE. In this paper, we(More)