Interference and SINR in Dense Terahertz Networks

Transcription

1 Interference and SINR in Dense Terahertz Networks V. Petrov, D. Moltchanov, Y. Koucheryavy Nano Communications Center Tampere University of Technology

2 Outline 1. Introduction to THz communications 2. Problem statement a. Recalling THz PHY b. Considered scenario c. Metrics of interest 3. System-level analysis a. Total interference b. SINR distribution 4. Numerical results a. Model validation b. Performance evaluation 5. Major outcomes

3 Immersive terahertz networks Illustration from Akyildiz et al. Terahertz band: Next frontier for wireless communications, 2014 Link level characteristics: q Extensive bandwidth: THz q Theoretical capacity: Tbits/s q Effective communication range: 1-5 m Truly 5G (Beyond 5G) technology System-level performance analysis is required

4 Problem statement q State of the Art: - Point-to-point THz communications ü Theoretically evaluated ü Experimentally validated - System-level aspects of THz communications Insufficiently studied q Problem: Existing models for free space propagation are not applicable due to special propagation properties of the THz waves q Goal: Design an analytical model for interference and SINR evaluation in THz networks

5 Recalling terahertz propagation Limited applicability of existing system-level models

6 Considered scenario q Random deployment in the cell q Poisson process with pin out infinitesimal neighbourhood q R cell radius (PL) q d 0 distance between Tx and Rx q d i distances from interferers, i [ 1: N] q λ nodes density q r minimum distance between nodes

7 Metrics of interest q Interference q SINR Densities are obtained using stochastic geometry

8 Analytical model (1) Total interference estimation q Based on Poisson deployment approximation q Let s now estimate the total interference level p kr 2 where probability of exactly k interferers being in, and G =1/ D 2 q The interference from each station is q Finally leading to

9 Analytical model (2) SINR distribution q The integral for SINR does not converge q However, the integral for log(sinr) does q In log scale division is replaced by substitution q Average SINR is given by q SINR pdf has the form

10 Numerical results (1) Total interference distribution q Transmit power 10dBm q Assumption: normal distribution of interference (lognormal in db scale) Used further q Perfect match with simulation results q Interference level grows with the nodes density Metric variance decreases as well

11 Numerical results (2) SINR distribution q Non-elementary distribution q Both mean and variance grow with the nodes density q Matches the simulation results as well Only analytical values on further plots

12 Numerical results (3) Interference + noise vs nodes density q Let s compare: Signal level degradation Interference level degradation q Interference grows with nodes density q Decreases with frequency (due to absorption) q But received power decreases as well (!)

13 Numerical results (4) SINR vs distance between Tx and Rx q Decreases fast with distance q Decreases with nodes density q Depends on the chosen frequency (due to absorption) q 20 db difference between 0.1THz and 1THz q (!)Difference tends to 0 at high nodes density q Interference level plays a substantial role in dense deployments

14 Conclusions q Major contributions: Analytical models for Interference and SINR in dense terahertz networks is developed The accuracy of the model is validated via extensive numerical simulations q Obtained results: Interference level must be taken into account even in low-dense THz networks Molecular noise level does not have any notable effect on the dense network scenario o Some simplifications in the propagation model can be performed