High Data Rate Mobile Communication Research Articles

Optical Mobile Communications: Principles, Implementation, and Performance Analysis

Owing to the rapid growth of mobile data communication and spectrum crunch at lower radio frequency, utilizing high frequency spectrum such as millimeter wave for ultra-high data rate mobile communications becomes necessary. Yet the propagation behaviors of high frequency radio waves make mobile communications rather challenging with a lot of technical problems, such as very large propagation loss. In this paper, we propose a novel approach, referred to as optical mobile communications (OMC), to cater to the need for high data rate mobile communication by exploiting optical beams. Taking spatial light modulator as an exemplary means of laser beam adaptation, we first present the system model of OMC. It is shown that the downlink channels in OMC are different from that in a system equipped with antennas emitting radio frequency signals. That is, the OMC channels for different mobile terminals are controllable to a large extent. This new feature creates a new dimension for performance optimization of OMC. We then investigate the achievable rate region of OMC using different multiple access schemes in a two-user downlink system. Numerical results show that expanded rate region can be achieved in OMC compared to the case where channels are not controllable, which shows the potential of OMC as a promising technique.

Impact of Group Mobility on QoS of Mobile WiMAX (IEEE 802.16e) Network with CBR Application

IEEE 802.16e is a wireless broadband network standard aimed at providing robust, high data rate mobile communication. With a modified IEEE 802.16e standard, it becomes possible to provide robust group mobility in battle zone or emergency operations that require centralized control. In these situations, the group mobility issues are very important to support the military and emergency applications, in which multiple mobile stations (MSs) could move in the same direction with short separations as a group. In this paper we designed a system to analyze the performance of mobile WiMAX network (IEEE 802.16e) based on QoS parameters (Throughput, Average jitter and Average end-to-end delay) in group mobility environment having different group size, while CBR application is going on. Keywords: - Group mobility, CBR, IEEE 802.16e, Group size, QoS

OFDM-Based Overlay Systems: A Promising Approach for Enhancing Spectral Efficiency [Topics in Radio Communications

Recently, several approaches for increasing spectral efficiency have been proposed to overcome the scarcity of spectral resources and to ensure that the ever-growing demand for high-data rate mobile communications can be met in the future. In this article, we focus on OFDM-based overlay systems that share a frequency band with already existing systems without degrading their performance. This is achieved by temporarily using those parts of the common frequency band that are currently not used by the licensed system. In particular, we focus on design issues for the physical layer as well as the medium access control layer and propose appropriate solutions for enabling coexistence. As a result, our investigations show that OFDM-based overlay systems are a promising approach for enhancing spectral efficiency.