Escalating demand of higher data rate in progressive generations for wireless environment involve work towards modification of modulation schemes over air interface. Beginning from TDMA/FDMA/CDMA based 2nd generation to highly complicated Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Interleaved FDMA (IFDMA) and Multicarrier CDMA (MC-CDMA) which are gaining attention for 4G networks. ...

A microstrip structure with a narrow return plane generates large common-mode radiation. The guard trace attached near the signal line can reduce common-mode radiation. In general, the guard trace needs a lot of via connections to the return plane for keeping the guard trace grounded. The guard trace with long intervals of vias causes resonance and additional radiation. We propose a novel techn...

We present a novel bandwidth (BW) efficient orthogonal frequency division multiplexing (OFDM) scheme with adaptive zeropadding (AZP-OFDM) for wireless transmission. Redundancy issues in OFDM based on cyclic prefix (CP), zero-padding (ZP), as well as no guard interval (NGI) systems are analyzed. A novel system design criterion based on the channel matrix condition is studied and applied to the d...

OFDM systems enable simple and e ective schemes to mitigate frequency selective fading channels. However, they are extremely sensitive to multiplicative uctuations induced by time-varying multipath delays, carrier o sets and oscillators' phase noise. Although the duration of OFDM symbols is chosen smaller than the channel coherence time to avoid, or reduce, channel time variations, this choice ...

This paper illustrates a channel sub-rating allocation policy for finite population cellular system. In this policy, certain channels are permitted to transiently divide into two channels at half the original rate to adapt handoff calls. As a result, one half can be employed to serve the existing call and the other half to serve the handoff request so that we can get rid of forced termination o...

In mobile radio communication, the fading channels generally exhibit both time-selectivity and frequencyselectivity. Orthogonal frequency division multiplexing has been proposed to combat the frequency-selectivity, but its performance is also affected by the timeselectivity. In this paper, we investigate how various parameters, such as the number of carriers, the guard time length and the sampl...