Abdulla Firag

Learn More
The queueing system considered is essentially a M/M/N/N queue where two types of users compete for the N resources. The users may have different arrival and service rates and are denoted as primary or secondary users. The primary users have priority access to the resources, and three levels of priority are considered: perfect priority, partial priority, and(More)
We develop practical time- and frequency-domain adaptive equalizers for distributed time-reversal space-time block-coded (TR-STBC) systems. The adaptive equalizers eliminate the need for explicit channel impulse response estimation at the receiver. The length of the time-domain adaptive equalizer is also independent of the data block length, making it(More)
This paper presents an ergodic capacity analysis of an amplify-and-forward multiple-input, multiple-output two-hop system including the source to destination (direct) link. We first derive an expression for the probability density function of an unordered eigenvalue of the system. Then, using this result, a closed form expression for the ergodic capacity of(More)
Reconfigurable antenna arrays offer advantages over traditional antenna selection in terms of requiring fewer physical antennas and the use of fixed antenna feeds. Hence, in this paper we analyze the signal to noise ratio (SNR) improvement offered by reconfigurable antennas and compare it to traditional selection. Both the distribution and the mean value of(More)
Keyhole fading present in some relay based applications can degrade the system performance. In this paper, we investigate the effect of multi-keyhole fading on the ergodic capacity of fixed infrastructure based multiple-input multipleoutput (MIMO) amplify-and-forward (AF) relaying systems. Specifically, considering a Rayleigh-multi-keyhole MIMO AF relay(More)
We propose a double-cap differential codebook (DCB) design for multiuser (MU) multiple-input-single-output systems. The MU transmission uses signal-to-leakage-and-noise ratio (SLNR) precoding. The double-cap DCB is designed for temporally/spatially correlated channels and is based on a combined spherical and polar cap structure. We consider an inner,(More)
The paper presents an ergodic capacity analysis of MIMO three product channels. We first derive the exact non-asymptotic and asymptotic probability density functions of the arbitrary eigenvalue of the system. From these, a non-asymptotic and asymptotic expression for the ergodic capacity of the system is derived. The non-asymptotic results involve several(More)