Diversity Combining for RF Energy Harvesting

RF energy harvesting (RFEH) is a promising technology for energy requirements of wireless communication nodes. However, providing sufficient amount of energy to ensure self-sufficient devices based on RFEH may be challenging. In this paper, the use of diversity combining in RFEH systems is proposed to increase the amount of harvested energy. The power consumption of diversity combining process is also taken into account to analyze the net benefit of diversity combining. Performances of RFEH systems are investigated for selection combining (SC), equal gain combining (EGC), and maximal ratio combining (MRC) techniques. Simulations are conducted to compare the numerical results of SC, EGC, and MRC, and the results show that although the diversity combining techniques can improve the energy harvesting performance, the power consumption parameters have a critical importance while determining the suitable technique

Diversity Combining for Fast Frequency Hopping Multiple Access Systems Subjected to Nakagami-m Fading

The achievable performance of various diversity combining schemes used in fast frequency hopping (FFH) aided M-ary frequency shift keying (MFSK) systems operating in a multiple access scenario subjected to Nakagami-m fading is investigated. Specifically, linear, self-normalization, hard limiting majority vote, soft limiting, product combining and order statistics-normalized envelope detection based diversity combining schemes are considered. The comparison of various diversity combining schemes is based on the achievable bit error rate versus the number of simultaneous users supported. It is shown using simulation results that although some of the combining schemes considered result in an inferior performance compared to the optimum soft limiting combiner, they offer the advantage of achieving an acceptable interference suppression performance without requiring side information

Soft-decision Viterbi decoding with diversity combining

Diversity combining methods for convolutional coded and soft-decision Viterbi decoded channels in mobile satellite communications systems are evaluated and it is clarified that the pre-Viterbi-decoding maximal ratio combining shows better performance than other methods in Rician fading channels by computer simulation. A novel practical technique for maximal ratio combining is proposed, in which the coefficients for weighting are derived from soft-decision demodulated signals only. The proposed diversity combining method with soft-decision Viterbi decoding requires simple hardware and shows satisfactory performance with slight degradation of 0.3 dB in Rician fading channels compared with an ideal weighting scheme. Furthermore, this diversity method is applied to trellis coded modulation and significant Pe performance improvement is achieved

Optimum predetection diversity receiving system Patent

Development of optimum pre-detection diversity combining receiving system adapted for use with amplitude modulation, phase modulation, and frequency modulation system

Diversity Combining Using Maxima Ratio Combining for All Modulation Mode

The destruction caused by channel can be seen by the existence of Amplitude and Phase Shift. By using the 6 Ways Diversity Combining method (6 Antennas/Receivers), it is expected that the disruption caused by Amplitude and Phase Shift can be suppressed as small as possible. In addition, by using diversity combining module, we will get a large SNR output which has a value sum of SNR of each diversity path. The design of Diversity combining module begins with MATLAB functional design as a big picture of the whole system. Subsequently, it will be made the hardware based on the MATLAB functional. This architectural design that will be the cornerstone in the MATLAB bit precision manufacturing. Then MATLAB bit precision will be designed as the foundation of the VHDL design. Diversity combining the output module meets the standards specified by the DVB consortium. In the hardware (FPGA) test results of diversity combining, the maximum working frequency is 44.56 MHz which has shown that is qualified with the standard sampling clock (9.142 MHz). This design also needs 4% of total FPGA Cyclone II 484I8 combinational units which is 2499 units and it needs also 3% of total register of FPGA Cyclone II 484I8 which is 1720 register units

Order Statistics Based Diversity Combining for Fading Channels

In this paper we present a new order statistics based diversity combining scheme (OSDC) for combining a set of independently fading signal amplitudes. The OSDC orders all the received signal amplitudes and uses only the two strongest signals in the combining process. The decision as to whether to use only the strongest or both the strongest and the next strongest is made depending on the relative strengths of these two highest order statistics. Signal-to-noise ratio performance of the new scheme is compared with that of the traditional schemes such as, selection combining, maximal ratio combining, equal gain combining, and a second order selection combining (SC2), for three channels, namely Rayleigh, Nakagami and exponential. The results show that OSDC performs as well as SC2