In the current age of advanced technologies, there is an escalating demand for reliable wireless systems, catering to the high data rates of mobile multimedia applications. This article presents a novel approach to the concept of Self-Concatenated Convolutional Coding (SECCC) with Sphere Packing (SP) modulation via Differential Space-Time Spreading- (DSTS-) based smart antennas. The two transmitters provide transmit diversity which is capable of recuperating the signal from the effects of fading, even with a single receiving antenna. The proposed DSTS-SP SECCC scheme is probed for the Rayleigh fading channel. The SECCC structure is developed using the Recursive Systematic Convolutional (RSC) code with the aid of an interleaver. Interleaving generates randomness in exchange for extrinsic information between the constituent decoders. Iterative decoding is invoked at the receiving side to enhance the output performance by attaining fruitful convergence. The convergence behaviour of the proposed system is investigated using EXtrinsic Information Transfer (EXIT) curves. The performance of the proposed system is ascertained with the H.264 standard video codec. The perceived video quality of DSTS-SP SECCC is found to be significantly better than that of the DSTS-SP RSC. To be more precise, the proposed DSTS-SP SECCC system exhibits an E b / N 0 gain of 8 dB at the PSNR degradation point of 1 dB, relative to the equivalent rate DSTS-SP RSC. Similarly, an E b / N 0 gain of 10 dB exists for the DSTS-SP SECCC system at 1 dB degradation point when compared with the SECCC scheme dispensing with the DSTS-SP approach.

In this research work, we have presented an iterative joint source channel decoding- (IJSCD-) based wireless video communication system. The anticipated transmission system is using the sphere packing (SP) modulation assisted differential space-time spreading (DSTS) multiple input-multiple output (MIMO) scheme. SP modulation-aided DSTS transmission mechanism results in achieving high diversity gain by keeping the maximum possible Euclidean distance between the modulated symbols. Furthermore, the proposed DSTS scheme results in a low-complexity MIMO scheme, due to nonemployment of any channel estimation mechanism. Various combinations of source bit coding- (SBC-) aided IJSCD error protection scheme has been used, while considering their identical overall bit rate budget. Artificial redundancy is incorporated in the source-coded stream for the proposed SBC scheme. The motive of adding artificial redundancy is to increase the iterative decoding performance. The performance of diverse SBC schemes is investigated for identical overall code rate. SBC schemes are employed with different combinations of inner recursive systematic convolutional (RSC) codes and outer SBC codes. Furthermore, the convergence behaviour of the employed error protection schemes is investigated using extrinsic information transfer (EXIT) charts. The results of experiments show that our proposed R a t e − 2 / 3 SBC-assisted error protection scheme with high redundancy incorporation and convergence capability gives better performance. The proposed R a t e − 2 / 3 SBC gives about 1.5 dB E b / N 0 gain at the PSNR degradation point of 1 dB as compared to R a t e − 6 / 7 SBC-assisted error protection scheme, while sustaining the overall bit rate budget. Furthermore, it is also concluded that the proposed R a t e − 2 / 3 SBC-assisted scheme results in E b / N 0 gain of 24 dB at the PSNR degradation point of 1 dB with reference to R a t e − 1 SBC benchmarker scheme.

Summary Recently, we have witnessed a remarkable proliferation of wearables in various smart applications. These applications include smart healthcare, smart military, smart infotainment, and smart industries, to name a few. However, wearables suffer from significant energy limitations. To cope with this challenging issue, energy harvesting can be a viable solution. In this paper, various ambient sources like heat, vibration, radio waves, and solar energy are compared and critically analyzed based on size, voltage, frequency, power density, and power. Critical analysis of vibrational, solar, heat, radiofrequency, and hybrid show convincing output results, but a hybrid solar wearable energy harvester (SWEH) and thermoelectric wearable energy harvester (TWEH) give a maximum output power of 501 mW. However, piezoelectric clothes fabrication is growing and coming out to be a good competitor because of flexibility and comfort. Work has been done on the hybridization of wearable clothes to generate maximum power and is good enough for wearable applications. On the other side, solar individually is enough to power wearable devices but for a specific time. In the radiofrequency still, research is required because of very low power generation or a flexible array can be integrated into a dress or certain other technique maybe adapted for flexible yet more power generation capability. Overall sizes of the reported wearable energy harvesters are in the millimeter to centimeter scale, with resonant frequencies in the range of 1 to 1400 Hz, while rectenna wearable energy harvester (RWEH) exceeds the limit and is reported in the range of 1.8 to 3.2 GHz. A maximum energy conversion for a piezoelectric wearable energy harvester can potentially reach up to 29.7 μW/cm3 and 14.28 μW/cm2. The power produced by the reported hybrid energy harvesters (HEHs) is in the range of 0.00012 to 501 mW. Due to the combined solar‐thermoelectric energy conversion in HEHs, these systems are capable of producing the highest power densities.

This work presents modeling, simulation, fabrication, and testing of a novel flow-based electromagnetic energy harvester (F-EMEH) for producing usable electrical energy from the pulsating fluid pressure levels within the pipeline. The power produced by the developed harvester can be effectively utilized for the operation of the wireless monitoring system of pipeline networks. The devised F-EMEH harvester consists of a stationary magnet positioned in the upper cap of the harvester and directly facing the wound coil that is fixed to a flexible latex membrane. The membrane along the coil when exposed to the pulsating fluid flow in the pipeline oscillates with respect to the stationary magnet. This relative motion of the membrane induced the voltage across the coil terminals. The harvester when applied to a pressure amplitude of 625 Pa generated an open circuit voltage of 1.2 V and a maximum load power of 18.6 μW when connected to 4.3 Ω load. Furthermore, when integrated to a voltage rectifier, an open circuit output of 4 V DC is achieved by the device at a pressure of 625 Pa. In addition, with the developed prototype, a 3.6 V, battery is charged up to 3.2 V within 30 min of duration. The voltage and power levels attained by the energy harvester can provide an easy solution for powering wireless sensor nodes mounted on a pipeline network for condition monitoring.

The development of special wearable/portable electronic devices for health monitoring is rapidly growing to cope with different health parameters. The emergence of wearable devices and its growing demand has widened the scope of self-powered wearable devices with the possibility to eliminate batteries. For instance, the wearable thermoelectric energy harvester (TEEH) is an alternate to batteries, which has been used in this study to develop four different self-powered wearable jacket prototypes and experimentally validated. It is observed that the thermal resistance of the cold side without a heat sink of prototype 4 is much greater than the rest of the proposed prototypes. Besides that, the thermal resistance of prototype 4 heat sinks is even lower among all proposed prototypes. Therefore, prototype 4 would have a relatively higher heat transfer coefficient which results in improved power generation. Moreover, an increase in heat transfer coefficient is observed with an increase in the temperature difference of the cold and hot sides of a TEEH. Thus, on the cold side, a heat flow increases which benefits heat dissipation and in turn reduces the thermal resistance of the heat sink. Besides that, the developed prototypes on people show that power generation is also affected by factors like ambient temperature, person’s activity, and wind breeze and does not depend on the metabolism. A different mechanism has been explored to maximize the power output within a 16.0 cm2 area, in order to justify the wearability of the energy harvester. Furthermore, it is observed that during the sunlight, any material covering the TEEH would improve the performance of prototypes. Prototypes are integrated into jacket and studied extensively. The TEEH system was designed to produce a maximum delivering power and power density of 699.71 μW and 43.73 μW/cm2, respectively. Moreover, the maximum voltage produced is 62.6 mV at an optimal load of 5.6 Ω. Furthermore, the TEEH (prototype 4) is connected to a power management circuit of ECT310 and LTC3108 and has been able to power 18 LEDs.