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Showing results 41 to 43 of 43
   Hybrid Analog-Digital Transceiver Designs for Cognitive Radio Millimiter Wave SystemsTsinos, Christos  ; Maleki, Sina ; Chatzinotas, Symeon et alin Hybrid Analog-Digital Transceiver Designs for Cognitive Radio Millimiter Wave Systems (2016) Recent advances in Milimeter wave (mmWave) band mobile communications may provide solutions to the increasing traffic demand in modern wireless systems. Even though mmWave bands are scarcely occupied, the ... [more ▼] Recent advances in Milimeter wave (mmWave) band mobile communications may provide solutions to the increasing traffic demand in modern wireless systems. Even though mmWave bands are scarcely occupied, the design of a prospect transceiver should guarantee the efficient coexistence with the incumbent services in these bands. To that end, in this paper, two underlay cognitive transceiver designs are proposed based on a hybrid Analog/Digital transceiver architecture that enables the mmWave spectrum access while controlling the interference to the incumbent users with low hardware complexity and power consumption. The first cognitive solution designs a codebook free cognitive hybrid pre-coder by maximizing the mutual information between its two ends subject to interference, power and hardware constraints related to the analog counterpart. The second solution is codebook based and exhibits less complexity than the first one at the cost of inferior spectral efficiency. A novel codebook free solution for the post-coder at the cognitive receiver part is further proposed, based on a hardware constrained Minimum Mean Square Error criterion. Simulations study the performance of both the proposed hybrid approaches and compare it to the one of a fully digital solution for typical wireless environments. [less ▲] Detailed reference viewed: 310 (28 UL)On-board the Satellite Interference Detection with Imperfect Signal CancellationPolitis, Christos ; Maleki, Sina ; Tsinos, Christos et alin 2016 IEEE 17th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC) (2016) Interference issues have been identified as a threat for satellite communication systems and services, resulting in throughput degradation and revenue loss to the satellite operators. In this context, an ... [more ▼] Interference issues have been identified as a threat for satellite communication systems and services, resulting in throughput degradation and revenue loss to the satellite operators. In this context, an on-board spectrum monitoring unit (SMU) can be used to detect interference reliably. Current satellite SMUs are deployed on the ground and the introduction of an in-orbit SMU can bring several benefits, e.g. simplifying the ground based station in multibeam systems. This paper proposes a two-step algorithm for on-board interference detection, exploiting the frame structure of DVB-S2X standard, which employs pilot symbols for data transmission. Assuming that the pilot signal is known at the receiver, it can be removed from the total received signal. Then, an Energy Detection (ED) technique can be applied on the remaining signal in order to decide the presence or absence of interference. The simulation results show that the proposed technique outperforms the conventional ED in low interference-to-signal and noise ratios (ISNRs). [less ▲] Detailed reference viewed: 297 (30 UL)Harmful Interference Threshold and Energy Detector for On-Board Interference DetectionPolitis, Christos ; Maleki, Sina ; Tsinos, Christos et alin 22nd Ka and Broadband Communications Conference 2016 (2016) Detailed reference viewed: 214 (15 UL) |
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