Cognitive Ultra Wideband Radio Research Articles

Green cognitive communication approaches

Generally one of the reasons for global warming is Co2 emission. The rapid growth of wireless communication is the reason for more emission. This creates more health issues, especially children. To reduce the issues, now the wireless communication is tilted towards green communication. Green communication cannot be achieved in single step. In this paper some of techniques are followed to achieve sustainable communication. The main objective of this paper is cognitive radio (CR), which makes use of spectrum in efficient way. In our proposed system, we focused on green cognitive cycle, Cognitive radio-Ultra wide band (CR-UWB) and Cognitive radio-Orthogonal Frequency Division Multiplexing (CR-OFDM). With these above methods we achieved better achievements in terms of efficiency, less time delay, resource utilization and low power for 5G wireless green communication.

RECONFIGURABLE FILTER ANTENNAS FOR PULSE ADAPTATION IN UWB COGNITIVE RADIO SYSTEMS

The design of fllter antennas with reconflgurable band stops is proposed. They are meant for employment in ultrawideband cognitive radio (UWB-CR) systems, where unlicensed users communi- cate using adaptive pulses that have nulls in the bands used by licensed users. Neural networks or circuits implementing the Parks-McClellan algorithm can generate such pulses. With fllter antennas, reconflg- urable bandstop fllters are flrst designed, to induce adaptive nulls in UWB pulses, and are then integrated in the feed line of a UWB an- tenna. The advantages of this combination are discussed. The fllters are based on split-ring resonators (SRRs) and complementary split-ring resonators (CSRRs). The relationship between the SRR and CSRR parameters and the stop band is also studied.

Spatial Capacity of Narrowband vs. Ultra-wideband Cognitive Radio Systems

Cognitive radio (CR) networks have emerged as attractive candidates to enhance radio spectral utilization efficiency on both licensed bands and license-free bands. This paper investigates the achievable sum capacity of spectrum-sharing CR networks, taking into account of channel multipath profiles, transmit power constraints, as well as the outage probability requirements from primary users holding spectrum licenses. Two transmission formats, narrowband versus ultra-wideband, are compared for adoption in CR networks. Capacity analysis indicates that ultra-wideband CRs are in general more suitable for networks operating over licensed bands, when strict outage requirements are imposed for protecting primary users. On license-free bands, on the other hand, narrowband CRs employing orthogonal channelization offer higher network capacity, while its ultra-wideband counterparts become competitive only when the multipath effect is moderate. In the presence of primary users, the interference temperature constraint limits the narrowband network more than its ultra-wideband counterpart.

ITERATIVE SOLUTION TO THE NOTCHED WAVEFORM DESIGN IN COGNITIVE ULTRA-WIDEBAND RADIO SYSTEM

Cognitive Ultra Wideband Radio is proposed to exploit the advantages of combining Cognitive Radio with Ultra Wideband technologies, so as to solve the problems of coexistence and compatibility between UWB and other existing narrowband wireless systems. A novel adaptive UWB pulse shaping algorithm with low complexity, instead of notch filter, is presented for producing the expected spectral notches right in the frequency band occupied by the nearby wireless devices. Simulation results show that the proposed UWB waveform has better single-link BER performances in AWGN channel and stronger anti-jamming ability than other conventional waveforms such as Scholtz’s monocycle, etc. Besides, the power spectral density of UWB pulse does not need to be reduced over the whole frequency band. Therefore, it is possible to expand the communication range of UWB systems by increasing the transmitted power of UWB pulse.

Research advances in cognitive ultra wide band radio and their application to sensor networks

The paper illustrates the novel concept of Cognitive UWB Radio, a wireless system based on UWB transmission able to self-adapt to the characteristics of the surrounding environment. First, salient features of UWB transmission are reviewed, and then, application of UWB characteristics to the problem of cognitive radio systems is discussed. Current ongoing studies and achieved results on a possible physical layer based on Prolate Spheroidal Wave Functions and consistent with the Cognitive UWB Radio paradigm are presented and analyzed, and their application to the sensor network scenario is discussed.

Multiple signal waveforms adaptation in cognitive ultra-wideband radio evolution

Cognitive ultra-wideband (UWB) radio is proposed to exploit the advantages and the unique features of enhancing UWB wireless technologies by utilizing cognitive radio functionality. In order to achieve the cognitive UWB radio, multiple pulse waveforms adaptation has been investigated for producing the expected spectral notches while matching with the Federal Communications Commission (FCC) spectral mask. Then the specifically designed pulse waveform with adaptive spectral notches is tested by high-speed digital processing unit for implementation estimation. To verify the pulse distortion effects of UWB antenna in the cognitive UWB radio, the generalized pulse waveform is further transferred through an actual UWB antenna. Furthermore, a pulse waveform predistortion scheme is considered before antenna transmission, so as to compensate the pulse distortion effects.