The simulation of vehicular wireless channels using geometry-based radio channel models is computationally intensive when the number of scatterers is significantly high. In this paper, we propose a new geometry-based stochastic channel model to simulate and analyze the aforementioned channels based on a framework developed from the theory of ambit processes. Under reasonable assumptions, the underlying mathematical structure of the proposed channel model enables the characterization of high mobility channels in terms of fading statistics, spatiotemporal channel correlation, and Doppler spectrum, besides ensuring tractable analysis. The developed algorithm facilitates fast simulation of high mobility channels and accounts for key features of vehicular channels including appearance and disappearance of multi-path components, spatial consistency, and captures the correlation between time-evolving delay and Doppler associated with multi-path components. Finally, we carry out simulations to obtain crucial insights about the characteristics of typical vehicle-to-infrastructure channels based on the proposed channel model.

Developing accurate and computationally efficient channel models for mobile wireless channels poses a formidable challenge, primarily due to the highly dynamic nature of such environments and the involvement of a large number of modeling parameters. In this paper, we propose a novel geometrical model to simulate mobile wireless channels based on a framework developed from the theory of ambit processes. Under reasonable assumptions, the underlying mathematical structure of the proposed channel model enables the characterization of mobile wireless channels in terms of fading statistics, spatio-temporal channel correlation, and Doppler spectrum, besides ensuring tractable analysis. Using the ambit process model, we develop an algorithm that enables fast simulation of macro-cellular channels and accounts for key features of such channels including the appearance and disappearance of multi-path components, spatial consistency, and further captures the correlation between time-evolving delay and Doppler associated with multi-path components. Finally, we simulate macro-cellular channels using the proposed algorithm to obtain crucial insights about the channel characteristics. Numerical results indicate that the proposed channel modeling approach serves as a fairly accurate and computationally efficient design framework for wireless communication systems.

Vehicle-to-infrastructure (V2I) and vehicle-to- vehicle (V2V) communications find extensive applications, particularly for congestion avoidance and road safety. However, development of such communication systems require accurate modeling of the wireless channel. This paper presents a methodology to simulate cross-road environments involving vehicular traffic. We propose a novel modeling approach for vehicular traffic based on a non-stationary one-dimensional Poisson arrival process which is represented by a M/M/infty queuing model. The joint ray-tracing of the stationary scatterers such as surrounding buildings along with stochastic modeling of mobile scatters such as vehicles reduces simulation time significantly, and yields relevant statistics of channel parameters with a minor compromise in accuracy.

Directional antennas in millimeter wave (mmWave) communication networks enable spatial reuse by reducing interference during concurrent transmission. However, higher spatial multiplexing gain is realized at the cost of increased power consumption in antenna arrays. In this paper, we develop a multi-slot scheduling scheme based on mixed integer linear programming (MILP) for energy efficient scheduling in mmWave concurrent transmission. Energy efficiency (EE) is defined as the ratio of data rate achieved to the sum of circuit power consumption and transmit power. EE is achieved by the joint optimization of data rate and power consumption; while the optimum data rate request is calculated using a reinforced learning strategy, power consumption is minimized through antenna beamwidth control. We also prove that the energy efficient scheduling problem is NP-complete, and propose three novel low complexity energy efficient scheduling algorithms for mmWave networks - energy efficient directional medium access control (EEDMAC)-Naive, EEDMAC-Greedy, and EEDMAC-Double Greedy (DGreedy). The proposed multi-slot scheduling scheme is seen to outperform the existing protocol in terms of EE, and delay fairness. We further analyze the degradation in system performance due to antenna scanning range. The simulation results provide fresh insights into resource allocation and scheduling for mmWave directional communications.

Millimeter wave (mmWave) communications utilizing directional antennas are capable to support multi-Gbps data rate spanning indoor short range to outdoor cellular scenarios. However, unique channel characteristics of mmWave channels including high pathloss, penetration loss and sparse multi-path characteristics requires new channel models for mmWave network design. In this paper, a novel geometry based model is introduced for outdoor directional non-line-of-sight (NLOS) mmWave channels. By approximating signal propagation with first order reflections from buildings, a more tractable analytical expression for average NLOS received signal power is obtained. Further, the accuracy of the model is tested using exhaustive simulations for different input parameters such as building density, antenna beamwidth etc.

Due to the large swath of available bandwidth, millimeter wave (mmWave) spectrum is potentially suitable to meet enhanced network capacity requirements of future generation communication systems. However, the high Analog to Digital Converter (ADC) sampling rate required to process wide band signals in the mmWave regime results in significant power consumption in the receiver hardware. In this work, an Orthogonal Frequency Division Multiplexing (OFDM) based subsampling architecture is proposed to achieve power efficient receiver design. Subbanding in association with orthogonal spreading codes using subsampling technique reduces the high sampling rate requirement of the receiver. Power consumption in the receiver is further reduced by utilizing low resolution ADC with minimal degradation in Bit Error Rate (BER) performance. In addition to this, OFDM transmission with reduced number of Fast Fourier transform (FFT) points alleviates the multi-path effects significantly, and improves the spectral efficiency. The combined effect of ADC bit resolution and subsampling on the system error performance and power consumption is studied.

Millimetre wave bands are envisaged to be utilised for next generation ultra‐high data rate communications due to the availability of large bandwidths. However, high sampling rate requirement at these frequencies leads to significant power consumption in the devices. In this study, a subband‐based subsampled radio architecture is proposed for indoor millimetre wave communications with the objective of improving power efficiency along with scalable data rates and multi‐user support under varying Quality of Service (QoS) requirements. An optimum bandwidth partitioning scheme is presented to support the proposed architecture. Subbanding in association with orthogonal spreading codes enables the reduction of sampling rate requirement at the receiver, resulting in significant power savings for medium data rate communication systems. Furthermore, the performance evaluation of the scheme is performed by deriving closed‐form analytical expressions for probability of bit error under line‐of‐sight (LOS) and non‐LOS conditions considering the effect of antenna half‐power beamwidth. The analytical expressions and simulation results for different requirements including maximum data rate, variable number of users, and variable QoS are evaluated and compared.

Millimeter wave communications is a promising technology for future multi-Gbps wireless networks. However, the wide bandwidth and high sampling rate requirement involved leads to significant power consumption in the communication systems. In this paper we propose a subband based subsampled system architecture for indoor millimeter wave communications with a primary objective of improving energy efficiency in the transceiver with scalable data rates and multi-user support for varying Quality of Service (QoS) requirements. An optimum bandwidth partitioning scheme in support of proposed system architecture is also presented. Subbanding in association with orthogonal spreading codes enables the reduction of sampling rate requirement at the receiver, resulting in significant power savings for medium data rate communication systems. The BER simulation results for variable data rate, number of users, and QoS support are presented for the proposed scheme.