Jialai Weng

Indoor Massive MIMO Channel Modelling Using Ray-Launching Simulation

Massive multi-input multioutput (MIMO) is a promising technique for the next generation of wireless communication networks. In this paper, we focus on using the ray-launching based channel simulation to model massive MIMO channels. We propose one deterministic model and one statistical model for indoor massive MIMO channels, both based on ray-launching simulation. We further propose a simplified version for each model to improve computational efficiency. We simulate the models in indoor wireless network deployment environments and compare the simulation results with measurements. Analysis and comparison show that these ray-launching based simulation models are efficient and accurate for massive MIMO channel modelling, especially with application to indoor network planning and optimisation.

Coverage Performance Analysis of FeICIC Low-Power Subframes

Although the almost blank subframes (ABSFs) proposed in heterogeneous cellular networks can enhance the performance of the cell range expansion (CRE) user equipments (UEs), it significantly degrades the macro-cell total throughput. To address this problem, the low power subframes (LPSFs) are encouraged to be applied in the macro-cell center region by the further-enhanced inter-cell interference coordination. However, the residual power of the LPSF, which interferes with the CRE UEs, and the proportion of the LPSF affect the downlink throughput together. To achieve a better rate coverage probability, the appropriate LPSF power and the proportion are required. In this paper, the analytical results of the overall signal to interference and noise ratio coverage probability and the rate coverage probability are derived under the stochastic geometric framework. The optimal region bias ranges for maximizing the rate coverage probability are also analyzed. The results show that the ABSF still outperform the LPSF in terms of rate with the optimal range expansion bias, but lead to a heavier burden on the backhaul of the pico-cell. However, with a static range expansion bias, the LPSF provide better rate coverage than the ABSF. In addition, in a low-range expansion scenario, the reduced power of the LPSF has negligible effect on the rate coverage with the optimal resource partitioning.

Realistic prediction of BER and AMC with MRC diversity for indoor wireless transmissions

Bit Error Rate (BER) is a key parameter used to evaluate the performance of radio communication systems. In this paper, a realistic BER of radio MRC diversity systems is predicted based on the Multi-Resolution Frequency Domain ParFlow (MRFDPF) model. The prediction takes into account the correlations among diversity branches and makes no assumptions of the correlation model. The predicted realistic BER for MRC diversity systems can be very useful to many wireless applications, such as, adaptive modulation and coding (AMC) scheme, or optimal power allocation.

A network deployment strategy for home area networks in smart grid

Reliability is one of the most concerned issues in wireless communications for smart grid, especially in the home area network(HAN) where the smart meter data are collected. In this paper, we model the HAN as a wireless mesh network that deploys cooperative transmissions for improving link reliability. We then define a new reliability performance metric that depends not only on the channel model but also on the locations of smart meters. Based on the reliability performance metric, we propose a smart meter deployment strategy to maximize the communication reliability. The performance of the proposed HAN deployment strategy is applied to a real home environment. The simulation results show that the proposed deployment strategy is effective in guaranteeing reliability for smart-grid communications.

How Densely Should Networks Be Deployed

In this work we try to answer the question how densely the wireless networks should be deployed. We modelled the base stations as a Poisson Point Process and derived an analytical form of the coverage probability under the path loss only channel condition. Surprisingly our result shows that the coverage probability is independent of the base station density. This suggests that when only considering distance-dependence path loss channel, the density of the networks has no influence on the network performance.

A mathematical formulation for MIMO channel map

Channel map has been widely used as an effective tool in network planning and deployment. However, there is a lack of mathematical formulation of the channel map as a tool for multiple-input multiple-output (MIMO) networks planning. In this work, we define and construct a MIMO channel map based on the extension of a mathematical formulation for the conventional single antenna channel map. We demonstrate the effectiveness of the constructed MIMO channel map in planning a distributed MIMO channel network through a numerical example. The results show that location optimisation in distributed MIMO systems gains significantly from an abstract formulation of the channel map.

On the use of an intelligent ray launching in MIMO channel modelling for network planning

Ray launching methods are not widely used in MIMO channel modelling due to its lack of complete channel characteristics, e.g. phase information, for the sake of computational efficiency. They usually calculate only mean-power loss at receiver locations. In this work, a fast MIMO channel modelling method is proposed based on a ray launching method. The model generates the phase information in a semi-random way and is combined with a ray launching model to get the MIMO channel state information.

A dual-polarisation modelling method for simulation-based propagation models

In this paper, we propose a universal dual-polarisation modelling method for the simulation-based propagation models. We adopt the universal definition of dual-polarisation radiation pattern and apply the definition to model the dual-polarised propagation channel. By adopting the universal definition of dual-polarisation using the ray reference, we clarify the misunderstanding caused by the widely accepted polarisation definition using ground reference. Furthermore, we integrate the universal dual-polarised model to a simulation-based propagation model. Simulation results demonstrate the effectiveness and potential of this dual-polarisation model in the simulation-based propagation models.