Joint Radar–Communications Exploiting Optimized OFDM Waveforms

We propose novel joint radar–communication spectrum sharing strategies exploiting orthogonal frequency-division multiplexing (OFDM) waveforms that concurrently achieve the objectives of both radar and communication systems. An OFDM transmitter is considered that transmits dual-purpose OFDM subcarriers such that all the subcarriers are exploited for the primary radar function and further exclusively allocated to the secondary communication function serving multiple users. The waveform optimization is performed by employing mutual information (MI) as the optimization criterion for both radar and communication operations. For the purpose of radar performance optimization, we consider the MI between the frequency-dependent target response and the transmit OFDM waveforms. On the other hand, communication system performance is evaluated in terms of the MI between the frequency-dependent communication channels of communication users with the transmit OFDM subcarriers. These optimization objectives not only enable the transmit power allocation of the OFDM subcarriers, but also govern the subcarrier distribution among the communication users. Two resource optimization scenarios are considered, resulting in radar-centric and cooperative resource allocation strategies that exploit convex and mixed-integer linear programming optimization problems for power allocation and subcarrier distribution, respectively. We further present a chunk subcarrier allocation approach that applies to both optimization strategies to reduce the computational complexity with a trivial performance loss. Simulation results are presented to illustrate the effectiveness of the proposed strategies.

A New Twofold Bargaining Game Paradigm for Wireless Energy Harvesting Algorithm

Considering the characteristics of radio-frequency-based energy harvesting technology, a number of smart devices are assisted by energy-constrained relays, which need to harvest energy from the hybrid access point (HAP). To design a novel energy harvesting mechanism, we investigate the integration of simultaneous wireless information and power transfer (SWIPT) and wireless powered communication network (WPCN) for dual-hop wireless communications. In our proposed scheme, we design a twofold bargaining game paradigm to adaptively make control decisions for conflicting requirements. According to two different bargaining solutions, we reveal the conflicting relationship of energy harvesting and information transferring and develop two time sharing procedures. In a compact iterative manner, these procedures work together to maximize the dual-hop communication system performance. Through simulation results, we conduct a numerical analysis and prove that our twofold bargaining approach leads to a higher system performance compared with the existing state-of-the-art protocols.

Focused and collimated Gaussian laser beam scintillation in weakly turbulent marine atmospheric medium

The scintillation index on the axis for Gaussian beams focused and collimated in weak marine turbulence is formulated via the usage of Rytov method. The average bit error rate <BER> is evaluated using this formulation. The scintillation index and <BER> versus propagation distance and source size are determined by using the log-normal distributed. Intensity for the collimated and focused. Gaussian beams, which are exhibited for wavelength, source size, focal length, and <SNR>. The focused beams are revealing more advantageous than collimated beams in an atmospheric marine environment. The findings of this study are significant for optical communication system performance in this layer.

3D Air-Ground Channel Model Reconstruction Based on the Experimental Data and Q-D Method

This paper proposes to use the Q-D (Quasi-Deterministic) method for reconstructing the angular and frequency characteristics of the 3D Air-to-Ground (A-G) channel from the available experimental data. This method allows to expand the applicability of tapped delay line (TDL) channel models for performance investigation of the aviation radio systems with directional antennas and multi-element antenna arrays. The developed 3D A-G channel models also give opportunity to take into account Doppler spread impact on the communication system performance.

Model Kanal 5G Frekuensi 28 GHz dengan Pengaruh Suhu di Kota Yogyakarta

ABSTRAKPenelitian ini melakukan pengujian pada model kanal 5G di jaringan masa depan. Karakteristik model kanal sangat mempengaruhi performansi jaringan pada penggunakan frekuensi mmWave di atas 6 GHz yang sensitif terhadap pengaruh alam. Oleh karena itu perlu untuk mengetahui karakteristik kanal agar menghasilkan performansi yang optimal. Evaluasi kerja pada penelitian ini menggunakan frekuensi 28 GHz, modulasi 16-QAM, bandwidth 50 MHz dan CPOFDM. Hasil penelitian menunjukkan perbandingan model kanal 5G untuk mendapatkan outage probability sebesar 10^-4 pada suhu maksimum dan minimum sehingga didapatkan Eb/No yang dibutuhkan untuk coding rate 1:2 adalah 17,26 dB dan 15,25 dB, coding rate 3:4 adalah 19,53 dB dan 17,45 dB dan coding rate 1 adalah 22,11 dB dan 19,82 dB. Hal ini menunjukkan bahwa suhu mempengaruhi performansi sistem komunikasi pada 5G dan menunjukkan bahwa dengan coding rate setengah lebih efisien dalam kualitas dan kapasitas kanal.Kata kunci: 5G, Model Kanal, Suhu, 28 MHz, CP-OFDM ABSTRACTThis research is testing the 5G channel model in the future network. The characteristics of the channel model greatly affect network performance in the use of mmWave frequencies above 6 GHz which are sensitive to natural influences. Therefore it is necessary to know the characteristics of the channel in order to produce optimal performance. The work evaluation in this study uses 28 GHz frequency, 16-QAM modulation, 50 MHz bandwidth and CP-OFDM. The results showed a comparison of the 5G channel model to get an outage probability of 10^-4 at maximum and minimum temperatures so that the Eb / No needed for coding rate 1:2 was 17.26 dB and 15.25 dB, coding rate 3:4 was 19.53 dB and 17.45 dB and coding rate 1 are 22.11 dB and 19.82 dB. This shows that the temperature affects the communication system performance at 5G and shows that with coding rate ½ and the minimum temperature is more efficient in the quality and capacity of the channel.Keywords: 5G, Channel Model, Temperature, 28 MHz, CP-OFDM