Ramoni Adeogun

Joint resource allocation for dual — Band heterogeneous wireless network

In this paper, we investigate downlink resource allocation in two-tier OFDMA heterogeneous networks comprising a macrocell transmitting at a microwave frequency and dual band small cells utilizing both microwave and millimeter wave frequencies. A non — cooperative game theoretic approach is proposed for adaptively switching the small cell transmission frequency based on the location of small cell users and interference to macrocell users. We propose a resource allocation approach which maximizes the sum rate of small cell users while minimizing interference to macrocell users and the total power consumption. The performance of the proposed resource allocation solution is evaluated via rigorous MATLAB simulations.

A Novel Game Theoretic Method for Efficient Downlink Resource Allocation in Dual Band 5G Heterogeneous Network

Hybrid heterogeneous wireless networks utilizing both traditional microwave frequency band and millimetre wave band are currently been investigated as a potential approach to meet the increasing demand for ultra-high rate transmission with the severe microwave spectrum scarcity and requirement for low power network devices. In this paper, we investigate downlink resource allocation in two-tier heterogeneous networks comprising of a macrocell transmitting at a microwave frequency and dual-band small cells utilizing both microwave and millimetre wave frequencies. We present a novel architecture with dual band small cell base stations. The small cell coverage area is divided into two regions where the users in the inner and outer regions are served by the associated small cells on millimetre wave and microwave frequencies, respectively. We formulate a two layer game theory based approach for maximizing energy efficiency and spectral efficiency of the system with optimal usage of available radio resources. The proposed game theoretic approach comprises of a non-cooperative frequency assignment game as its first layer and a multi-objective optimization based game as the second layer. In the frequency assignment game, each small cell base station selects a frequency band from either the microwave band or millimetre wave band for each of its associated users by maximizing the data rate of its users. The solution to the frequency assignment game is obtained via Pure Strategy Nash Equilibrium. The utility function of the game in the second layer involves power and sub-carrier allocation via the joint maximization of both energy efficiency and spectral efficiency of the network. The utility function is formulated as a multi-objective optimization problem which is converted into a single objective problem and solved using Lagrangian dual relaxation. Simulations results show that the proposed dual band heterogeneous network with game theoretic resource allocation offers improved sum rate, energy efficiency and spectral efficiency compared to classical shared spectrum heterogeneous network utilizing only microwave frequency band.

Channel prediction for millimeter wave MIMO systems in 3D propagation environments

This paper presents a channel prediction method for MIMO systems operating at millimeter wave (mmWave) frequencies in 3D propagation environments. Based on recent 3D model for mmWave channels, an ESPRIT/Unitary ESPRIT approach is proposed for jointly extracting the azimuth, elevation and Doppler parameters of the channel. The MMSE minimum description length (MMDL) criterion is utilize for proper selection of the number of dominant paths. Temporal extrapolation of the estimated model is then performed to obtain future states of the channel. A closed form expression for the performance bound on the estimation and prediction of 3D multiantenna channels with uniform planar array is also derived. The performance of the method is evaluated via numerical simulations.

Performance analysis of two-tier multiantenna 5G heterogeneous wireless networks with dual band transmission

The goal of this paper is to present and analyze the performance of new multiantenna heterogeneous network architectures utilizing both the microwave and millimeter wave frequency bands. Two new architectures are presented viz: microwave macrocell base station with dual band small cell base stations and dual band macrocell base station with mmWave small cell base stations. The effect of dynamically selecting transmission frequency and adjusting coverage regions for each frequency band on the proposed architectures is evaluated via rigorous simulation. We perform simulations to study the performance of Zero Forcing (ZF) based transmit beamforming for interference coordination on the two architecture and compare with classical single band heterogeneous network architecture. Our results show that the proposed dual band architectures offer improved sum rate performance over classical single band networks. The performance gain increases with increasing network densification. We observe that the architecture with dual band small - cell base stations offer better performance when compared with the architecture utilizing dual band air interface at the macro-cell base station. The effect of varying mmWave coverage distance on the performance of the proposed network architectures is also evaluated. Our simulation results shows that decreasing/increasing the inner radius of the small - cells results in significant decrease/increase in both sum rate and per user rate. However, no significant change in rate is observed with similar variation in the macro - cell millimeter wave coverage area.

An adaptive parametric prediction method for mobile MIMO wireless systems

In this paper, we investigate the prediction of mobile MIMO channels with varying multipath parameters. Based on the PAST algorithm, we propose a multidimensional adaptive ESPRIT approach for jointly tracking the evolution of the Doppler frequencies and spatial directions of arrival and departure of the propagation paths. Future states of the channel are predicted using the last estimate of the propagation parameters. We show via simulation that the proposed adaptive method outperforms existing static approaches with varying channel parameters. Our results indicate that the performance improvement from parameter tracking is dependent on the rate of variation of the underlying multipath parameters.