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Javad Sayehvand

Publications and source records attributed to Javad Sayehvand.

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Interference and Coverage Analysis in Coexisting RF and Dense TeraHertz Wireless Networks

This paper develops a stochastic geometry framework to characterize the statistics of the downlink interference and coverage probability of a typical user in a coexisting terahertz (THz) and radio frequency (RF) network. We first characterize the exact Laplace Transform (LT) of the aggregate interference and coverage probability of a user in a THz-only network. Then, for a coexisting RF/THz network, we derive the coverage probability of a typical user considering biased received signal power association (BRSP). The framework can be customized to capture the performance of a typical user in various network configurations such as THz-only, opportunistic RF/THz, and hybrid RF/THz. In addition, asymptotic approximations are presented for scenarios where the intensity of THz BSs becomes large or molecular absorption coefficient in THz approaches to zero. Numerical results demonstrate the accuracy of the derived expressions and extract insights related to the significance of the BRSP association compared to the conventional reference signal received power (RSRP) association in the coexisting network.

cs.NI

Performance analysis of hybrid FSO/RF communication systems with Alamouti Coding or Antenna Selection

In this work a novel dual-hop relay-assisted hybrid Free Space Optical / Radio Frequency (FSO / RF) communication system is presented. In this system, RF signal is transmitted from two antennas, and then forwarded by a single antenna relay through FSO channel. This is the first time that performance of using Alamouti Coding (AC) or Antenna Selection (AS) at the transmitter of a hybrid FSO / RF system is investigated. FSO link has Gamma-Gamma atmospheric turbulence, and in order to get closer to the actual results, the effect of pointing error is also considered. For the first time closed-form expressions are derived for Bit Error Rate (BER) and Outage Probability of the proposed system and validated through MATLAB simulations. Results indicate that in this structure, there is slight performance difference between AC and AS schemes. Hence due to more complexity, power consumption and latency of AC, AS is recommended. Dual-hop, hybrid FSO / RF system significantly improves performance and reliability of the system, and is particularly suitable for long-range applications that direct RF communication between source and destination is not possible. Considering these advantages this structure is particularly suitable for mobile communications which has power and processing limitations.

eess.SP