Refine
Department, Institute
Document Type
- Conference Object (7)
- Article (1)
- Part of a Book (1)
Keywords
- Chaotic Transceiver (1)
- FM Modulation (1)
- On-Off Keying (1)
- cognitive radio (1)
- cooperative sensing (1)
- energy detection (1)
- fusion centre (1)
- spectrum sensing (1)
- throughput maximization (1)
The paper presents the design of a baseband pi/4-DQPSK complex wavelet packet modulation CWPM transceiver and the results of its FPGA implementation. The design uses 8-point Discrete Wavelet Packet Transform (DWPT) and its inverse as core processing modules. All modules have been designed using VHDL programming language together with the Altera software tools Quartus II 9.1 and ModelSim 6.5b. The transceiver was implemented on a Cyclone III board.
High peak to average power ratio (PAPR) of a transmitted signal is one of the major drawbacks of the complex wavelet packet modulation (CWPM) as usual in any multicarrier communication system. Utilizing the advantage of concentrating the energy to certain subspaces of the discrete wavelet transform, many PAPR reduction techniques are proposed to solve this problem like threshold and clipping methods. In this paper a novel hybrid PAPR reduction method for CWPM called Threshold-Clipping (TC) method has been proposed. The simulation results in Rayleigh multipath fading channel show that the proposed scheme has achieved 4.5 dB and 3 dB reduction in PAPR over the traditional threshold and clipping methods respectively with less than 0.5 dB degradation in bit error probability.
The requirements of an efficient communication scheme for wireless sensing applications have been investigated. The noncoherent direct chaotic communication scheme called chaos on-off keying (COOK) has presented itself as a promising candidate. This paper proposes a modified version of the COOK scheme to improve its performance in noisy and fading environments. The proposed scheme is designed to increase the signal space of the decision variable by using the concept of differential correlation keeping implementation requirements simple. The results show that the proposed modified version of the COOK scheme achieves less bit-error probability in noisy and fading channels at moderate signal-to-noise ratio values and almost constant detection threshold as compared with the original version.
This paper presents the design procedure and implementation results of an amplitude modulation (AM) double sideband – Large carrier (DSB-LC) receiver using an Altera FPGA EP3C120 development board. The design is first implemented in MATLAB/Simulink(TM) using also embedded MATLAB(TM) blocks. It is then automatically converted to VHDL level with the Simulink HDL coder. The VHDL code is then synthesized and fitted with QuartusII ®; software and downloaded to the Altera CycloneIII EP3C120 FPGA development board. The results show that this approach makes it is easy for students to understand and develop the reception of AM signals using programmable logic tools. It also presents an efficient design flow for realizing design modules using MATLAB.
Cost efficient energy monitoring in existing large buildings demands for autonomous indoor sensors with low power consumption, high performance in multipath fading channels and economic implementation. Good performance in multipath fading channels can be achieved with noncoherent chaotic modulation schemes such as chaos on-off keying (COOK) or differential chaos shift keying (DCSK). While COOK stands out in the area of power consumption, DCSK excels when it comes to its performance in noisy and multipath fading channels. This paper evaluates a combination of both schemes for autonomous indoor sensors. The simulation results show 50% less power consumption than DCSK and more than 3dB SNR gain in Rayleigh fading channels at BER=10-3 as compared to COOK, making it a promising candidate for low power transmission in autonomous wireless indoor sensors. We further present an enhanced version of this scheme showing another 1 dB SNR improvement, but at 25% less power consumption than DCSK.
In this paper, the performance evaluation of Frequency Modulated Chaotic On-Off Keying (FM-COOK) in AWGN, Rayleigh and Rician fading channels is given. The simulation results show that an improvement in BER can be gained by incorporating the FM modulation with COOK for SNR values less than 10dB in AWGN case and less than 6dB for Rayleigh and Rician fading channels.
