Average Error Probability Analysis in mmWave Cellular Networks

In this paper, a mathematical framework for the analysis of average symbol error probability (ASEP) in millimeter wave (mmWave) cellular networks with Poisson Point Process (PPP) distributed base stations (BSs) is developed using tools from stochastic geometry. The distinguishing features of mmWave communications such as directional beamforming and having different path loss laws for line-of-sight (LOS) and non-line-of-sight (NLOS) links are incorporated in the average error probability analysis. First, average pairwise error probability (APEP) expression is obtained by averaging pairwise error probability (PEP) over fading and random shortest distance from mobile user (MU) to its serving BS. Subsequently, average symbol error probability is approximated from APEP using the nearest neighbor (NN) approximation. ASEP is analyzed for different antenna gains and base station densities. Finally, the effect of beamforming alignment errors on ASEP is investigated to get insight on more realistic cases.Comment: Presented at IEEE VTC2015-Fal

A Normalization Model for Analyzing Multi-Tier Millimeter Wave Cellular Networks

Based on the distinguishing features of multi-tier millimeter wave (mmWave) networks such as different transmit powers, different directivity gains from directional beamforming alignment and path loss laws for line-of-sight (LOS) and non-line-of-sight (NLOS) links, we introduce a normalization model to simplify the analysis of multi-tier mmWave cellular networks. The highlight of the model is that we convert a multi-tier mmWave cellular network into a single-tier mmWave network, where all the base stations (BSs) have the same normalized transmit power 1 and the densities of BSs scaled by LOS or NLOS scaling factors respectively follow piecewise constant function which has multiple demarcation points. On this basis, expressions for computing the coverage probability are obtained in general case with beamforming alignment errors and the special case with perfect beamforming alignment in the communication. According to corresponding numerical exploration, we conclude that the normalization model for multi-tier mmWave cellular networks fully meets requirements of network performance analysis, and it is simpler and clearer than the untransformed model. Besides, an unexpected but sensible finding is that there is an optimal beam width that maximizes coverage probability in the case with beamforming alignment errors.Comment: 7 pages, 4 figure

A grid-based coverage analysis of urban mmWave vehicular ad hoc networks

In this letter, a tractable coverage model, specifically designed for urban vehicular ad hoc networks, is presented to aid a better system designer. This is achieved through the use of a model based upon line processes, which simplifies the analysis. It is found, that even in crowded interferer scenarios, mmWave vehicular communications can establish reliable links with an SINR threshold of around 5 dB, with a coverage probability of approximately 0.8 at 50 m separation between a typical transmitter and a typical receiver. These results, and their inference towards the design and deployment of urban vehicular ad-hoc networks, may impact the developments of future vehicle- to-vehicle (V2V) applications and services

Capacity and Outage of Terahertz Communications with User Micro-mobility and Beam Misalignment

User equipment mobility is one of the primary challenges for the design of reliable and efficient wireless links over millimeter-wave and terahertz bands. These high-rate communication systems use directional antennas and therefore have to constantly maintain alignment between transmitter and receiver beams. For terahertz links, envisioned to employ radiation patterns of no more than few degrees wide, not only the macro-scale user mobility (human walking, car driving, etc.) but also the micro-scale mobility - spontaneous shakes and rotations of the device - becomes a severe issue. In this paper, we propose a mathematical framework for the first-order analysis of the effects caused by micro-mobility on the capacity and outage in terahertz communications. The performance of terahertz communications is compared with and without micro-mobility illustrating the difference of up to 1 Tbit/s or 75%. In response to this gap, it is finally shown how the negative effects of the micro-mobility can be partially addressed by a proper adjustment of the terahertz antenna arrays and the period of beam realignment procedure.Comment: Accepted to IEEE Transactions on Vehicular Technology on April 9, 2020. Copyright may be transferred without further notice after which this version may become non-availabl

Joint power and beamwidth optimization for full duplex millimeter wave indoor wireless systems

In this paper, a joint power and beam-level beamwidth control scheme is proposed for full duplex (FD) millimeter wave (mmWave) indoor wireless systems. Energy efficiency of the proposed scheme is investigated considering various system parameters, such as maximum transmit power level, level of self-interference cancellation and pilot transmission overhead. With this analysis for a realistic indoor wireless communication scenario, the feasibility of FD is studied for mmWave links, considering their specific propagation characteristics, namely, narrow transmission and reception beam-level beamwidths and high absorption losses, as well as massive bandwidth which is much larger than the existing sub 6 GHz bands. We evaluate the performance of the proposed FD mmWave system for three power budget schemes (low, moderate and high) in terms of average total energy efficiency. Our simulation results show that, for currently available state-of-the-art self-interference cancellation levels, FD mmWave with proposed joint power and beam-level beamwidth control outperforms the smart half duplex (HD) mmWave with joint transmission slot and beam-level beamwidth control by a factor of up to four times and improves FD mmWave with only power control by up to 33.92 %. If higher (close to ideal) selfinterference cancellation can be achieved, the net average total energy efficiency improvements over existing abovementioned schemes, are up to 4.8 times and 26.45 %, respectively. It is concluded that with the proposed joint power and beamwidth control, the current FD mmWave technology promises a good potential for indoor wireless networks