RO-like ring-based TRNG with adaptive mode switching for enhanced entropy Harvesting

The video performance benefits of burst-by-burst adaptive modulation are studied, employing a higher-order modulation mode, when the channel is favourable, in order to increase the system's bits per symbol throughput and conversely, invoking a more robust, lower-order modulation mode, when the channel exhibits inferior channel quality. It is shown that due to the proposed adaptive modem mode switching regime a seamless video-quality versus channel quality relationship can be established, resulting in error-free video quality right across the operating channel signal-to-noise ratio (SNR) range.

A discrete wavelet transform (DWT) based codec with EBCOT/adaptive coding mode switching/low-band-shift (LBS) is presented in this paper. The adaptive coding mode switching is used for both intra- and inter-frame coding, respectively, to improve the rate vs. distortion (R-D) performance. EBCOT, the coding engine used in JPEG2000 is adopted in this framework because of its embedded R-D optimization capability which is most suitable for the application of a perceptual distortion measure (PDM). LBS is used for motion estimation (ME) in DWT domain, while context based MQ coding is adopted to code the motion vector (MV). The context design of MV coding is derived from H.264.

In this paper, we propose a mechanism to switch between multiple-input multiple-output (MIMO) with two transmit antennas and single-input multiple-output (SIMO) to conserve mobile terminals' energy. We focus on saving uplink RF transmission energy of mobile terminals in cellular systems supporting best effort traffic. The key idea is to judiciously slow down transmission rates when a base station is underutilized. We show that there exists a crossover point on the transmission rate below which SIMO consumes less power than MIMO when circuit power is included. The crossover point is an increasing function of the circuit power, the number of receive antennas and channel correlation, all of which increase the potential energy savings resulting from mode switching. We propose an adaptive mode switching algorithm combined with rate selection to maintain a user's target throughput while achieving energy efficiency. Extensive flow-level simulations under dynamic loads confirm that the proposed technique can reduce the transmission energy by more than 50% and enables an effective tradeoff between file transfer delay and energy conservation.

In cognitive radio, the throughput efficiency of the secondary user (SU) is determined by spectrum sensing performance and the secondary user's available power to send data. Because the secondary user expends energy for spectrum detection and to maintain cooperation among numerous SUs, transmission power can be reduced. To compensate for this energy, cognitive radio has devised an energy harvesting technology in which the SU may harvest energy from the primary (PU) signal and use it to broadcast data and extend the lifetime. In a typical Energy Harvesting Cognitive Radio Network (EHCRN), SU can perform sensing and harvesting in different slots, reducing the secondary user's transmission time and lowering throughput. In a cooperative wireless network with energy detecting spectrum sensing, the RF energy harvesting approach is researched, and various optimization studies are investigated in this work. First, an energy harvesting is considered with the power splitting technique, Power Splitting Energy Harvesting Cognitive Radio Network (PSEHCRN) to measure the residual energy of SU that can be utilize to improve the transmission efficiency of SU and obtained expressions for throughput and lifetime. Further an energy harvesting with adaptive time switching mode of operation namely Adaptive Time Switching Energy Harvesting CRN (ATSEHCRN) has proposed and analyses the performance in terms of harvested energy, transmission power, throughput and lifetime of SU. This research also offers the Optimum Energy Harvesting Cognitive Radio Network (OTEHCRN)., an optimum energy harvesting technique that can perform spectrum sensing and energy harvesting simultaneously, with the entire incoming radio frequency (RF) power being utilised for energy harvesting. Reduced energy consumption paired with higher energy harvesting allows more energy to be accessible for transmission, resulting in increased SU throughput and longevity. Harvested energy, transmission power, throughput and lifetime are analysed with half duplex and full duplex mode of energy harvesting and compared with the different energy harvesting schemes. The cognitive radio performance of all studies has been verified with MATLAB simulation results.

How should females and males move to search for partners whose exact location is unknown? Theory predicts that the answer depends on what they know about where targets can be found, raising the question of how actual animals update their mate search patterns to increase encounter probability when conditions change. Here, we show that termites adaptively alternate between sexually monomorphic and dimorphic movements during mate search. When the location of potential mates was completely unpredictable, both sexes moved in straight lines to explore widely. In contrast, when the stray partner was at least nearby, males moved while females paused. Data-based simulations confirmed that these movements increase the rate of successful encounters. The context-dependent switch of search modes is a key to enhance random encounters.

A 5.0-V 2.0-A flyback power supply controller providing constant-voltage (CV) and constant-current (CC) output regulation without the use of an optical coupler is presented. Dual-close-loop control is proposed here due to its better regulation performance of tolerance over process and temperature compared with open loop control used in common. At the same time, the two modes, CC and CV, could switch to each other automatically and smoothly according to the output voltage level not sacrificing the regulation accuracy at the switching phase, which overcomes the drawback of the digital control scheme depending on a hysteresis comparator to change the mode. On-chip compensation using active capacitor multiplier technique is applied to stabilize the voltage loop, eliminate an additional package pin, and save on the die area. The system consumes as little as 100 mW at no-load condition without degrading the transient response performance by utilizing the adaptive switching frequency control mode. The proposed controller has been implemented in a commercial 0.35-μm 40-V BCD process, and the active chip area is 1.5 × 1.0 mm2. The total error of the output voltage due to line and load variations is less than ±1.7%.